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Physico-Chemical Characteristics of Rice BranProcessed by Dry Heating and Extrusion CookingH R Sharma a G S Chauhan a amp Kuldeep Agrawal aa Department of Food Science and Technology G B Pant University of Agriculture andTechnology Pantnagar US Nagar UA IndiaPublished online 06 Feb 2007

To cite this article H R Sharma G S Chauhan amp Kuldeep Agrawal (2004) Physico-Chemical Characteristics of Rice BranProcessed by Dry Heating and Extrusion Cooking International Journal of Food Properties 73 603-614 DOI 101081JFP-200033047

To link to this article httpdxdoiorg101081JFP-200033047

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INTERNATIONAL JOURNAL OF FOOD PROPERTIES

Vol 7 No 3 pp 603ndash614 2004

Physico-Chemical Characteristics of Rice Bran

Processed by Dry Heating and Extrusion Cooking

H R Sharma G S Chauhan and Kuldeep Agrawal

Department of Food Science and Technology G B Pant University of

Agriculture and Technology Pantnagar US Nagar UA India

ABSTRACT

Rice bran was stabilized by dry heat and extrusion cooking method Physico-

chemical functional and storage characteristics of stabilized rice bran were

evaluated The rice bran stabilization affected its crude fat and crude ash contents

significantly whereas the other constituents remained almost unchanged The

content of reducing nonreducing and total sugars remained unaffected and

did not differ significantly from raw rice bran The neutral detergent fiber (NDF)

contents of raw and dry-heat treated rice bran did not differ significantly

However after extrusion stabilization the NDF increased significantly Similar

effects were observed in composition of gum fiber and total fiber The

stabilization of rice bran had a significant reduction in lysine and phytic acid

content Bulk density and water absorption were higher in extruded stabilized rice

bran than dry-heat treated bran Protein solubility was maximum in raw bran

whereas damaged starch content was higher in stabilized bran Color of the

extruded bran was dark brown whereas that of dry-heat stabilized was light

brown It was observed that dry-heat treated bran was stored up to 30 days

Correspondence G S Chauhan Department of Food Science and Technology G B Pant

University of Agriculture and Technology Pantnagar-263 145 US Nagar UA India E-mail

gschauhan46yahoomailcoin

603

DOI 101081JFP-120040213 1094-2912 (Print) 1532-2386 (Online)

Copyright amp 2004 by Marcel Dekker Inc wwwdekkercom

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whereas extruded bran was stored up to 60 days without any changes in the free

fatty acid content

Key Words Rice bran stabilization Composition Functional properties

Nurtitional properties Storage

INTRODUCTION

Rice is a major food commodity throughout the world India is the largest

producer of rice in the world outside main land of China in productionwise For value

addition low grade rice have been used for extrusion cooking to manufacture

expanded crunchy snacks[1] Based on production the potential availability of rice

bran a by-product of rice milling industry was estimated to be about 5 million metric

tonnes per annum[2] The rice bran refers to the coating removed from brown rice

during the process of milling The bran constitutes nearly 85of the total grain and is

highly nutritious[3] Raw rice bran has ac characteristic bland flavor slightly bitter

and sweet taste Bran flavor is frequently descried as incipient rancid musty and sour

because of its readily deterioration in commercial lots[4] It contains 12ndash25 fat 10ndash

16 protein 10ndash20 starch 3ndash8 reducing sugars 8ndash11 hemicelluloses 10ndash12

celluloses 6ndash15 crude fiber and 65ndash10 ash content Rice bran is abundant in

vitamins of the B group and tocopherols and is poor in vitamins A and C[5] Several

human and animal studies conducted to date suggest that rice bran has interesting

health benefits It appears to be as effective as wheat bran as a laxative aid effective

hypocholesterolmic agent as well as several other health benefits reported in

literature[67] Since rice bran contains less soluble fiber its cholesterol lowering and

other health enhancing properties may be related to associated compounds These

include rice bran oil plant sterols tocopherols oryzanol and b-sitosterol[8] Although

the nutritional and food potential of rice bran have been recognized the consumption

of rice bran in human foods has been limited to a very small quantity This may be

partially due to the result of lipid deterioration by the enzymes such as lipase growth

inhibitors microorganisms and insects in rice bran[6] Several types of heat

stabilization procedures have been mentioned which involve the application of dry

or moist heat treatments for a sufficient time to arrest the activity of spoilage agencies

such as lipases and destroy the antinutritional factors[9] Baked foods provide one of

the most potential possibilities of utilizing rice bran in foods Uses of rice bran are

advocated in making breads muffins pan cakes cookies cakes pies extruded

snacks and breakfast cereals The stabilization of rice bran by using extrusion

cooking and dry heat treatment is practical and has the commercial potential

therefore these two method of stabilization were compared[10] The stabilization of

rice bran has been reported to improve nutritional functional and keeping quality of

rice bran[11] Considering the nutritional and food potential and associated health

benefits of consuming rice bran the present investigation was planned to compare the

effects of dry heat treatment with that of extrusion cooking on the physico-chemical

characteristics of rice bran and their stability during storage

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MATERIALS AND METHODS

Fresh rice bran was procured from MS Shakti Rice Mills Rudurpur (UA)India Rice bran was stabilized immediately after procurement using dry-heat andextrusion cooking as described below

Dry Heat Stabilization

Rice bran was transferred to open shallow pans and spreaded uniformly in thinlayers The pans were then placed in the oven maintained at 120C and dried for30min The dried bran was ground to pass through screen (032mm) of the Fitz(Fitz company USA) mill to produce particle size close to wheat flour The branwas stored at an ambient temperature in polyethylene bags for further use

Extrusion Stabilization

It was preformed using a Wenger X-5 Laboratory Extruder (Wenger Mfg CoSabetha KS USA) with the following conditions Water flow rate 0000038m3sfeed rate 27 kghr steam supply 27580 kPa die opening 00078m temperature135ndash140C Extrudates were air dried at 50C for 24 h and ground in a Fitz Millto pass through 032mm screen of the mill as in dry heat method The bran wasstored at an ambient temperature in polyethylene bags for further use

Chemical Composition

The samples of bran were analyzed for moisture protein (N 595) crude fattotal ash crude fibre calcium and sugars according to AACC[12] methods Thepercent values of moisture protein fat ash and crude fiber were subtracted from100 and the remainder was expressed as carbohydrates (by difference) Calorificvalue (kJ100 g) was calculated from the physiological fuel values of protein fatand carbohydrates While the color of different bran samples was noted visuallyNeutral detergent fiber was determined according the method described by theworker[13] The method is based on the extraction of the food with hot neutraldetergent solution The residues (NDF) contain lignin cellulose hemicellulose andcell wall protein

Gum fiber was determined according to the procedure described by Sharma[14]

One gram sample was extracted with 25mL of acetic acid solution by stirring atroom temperature for 30min The contents were centrifuged for 20min at 6500 rpmand the supernatant recovered The process of extraction and centrifugation wasrepeated four times and supernatants were pooled Gum was precipitated frompooled acetic acid extract by the addition of ethanol with stirring till 50concentration of ethanol was reached The suspension was centrifuged and thesupernatants were decanted The precipitate was again washed with ethanol andacetone and dried at 50C to a constant weight Total fiber was roughly calculated

Physico-Chemical Characteristics of Rice Bran 605

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as the sum of neutral detergent fiber and gum fiber according to the methoddescribed by worker[14]

Available lysine was determined by Carpenter method[15] which is based on thereaction of fluorodinitrobenzene (FDNB) with the epsilon-NH2 group of lysine inthe proteins and the colorimetric determination of the DNP-lysine obtained bysubsequent acid hydrolysis Method of Haug and Lantzsch[16] was used to estimatethe phytic acid content in rice bran sample In this method sample extract washeated with acidic iron (ferric) solution of a known iron content The decrease in iron(determined colorimetrically with 2ndash2 bipyridine) in supernatant is a measure ofphytic acid content Free fatty acid contents of raw and stabilized rice bran weredetermined by AACC method[12]

Functional Characteristics

Bulk density of raw and stabilized bran were determined by method ofNarain et al[17] Water absorption capacities of raw and stabilized rice bran weremeasured by a modified method reported by Sosuliski[18] Sample of 25 g wasdispersed with 25mL of water in a 50mL centrifuge tube and allowed the mixtureto stand for 15min at 25C then centrifuged the sample at 3200 rpm for 15minThe amount of water retained by the solids was measured Fat absorption of ricebran were estimated by mixing 5 g sample with 50mL corn oil allowing the mixtureto stand for 15min at room temperature and then centrifuging at 3200 rpm for15min The fat retained by the solids was measured[19]

Fortuin method[20] was followed to determine the protein solubility of branWeighed sample (25 g) was dispersed in 100mL distilled water and stirred for 1 h ata controlled temperature of 50C The solution was then centrifuged for 30min at3200 rpm The supernatant was collected in a flask and the nitrogen content wasdetermined by Kjeldahl method[12] Damaged starch in rice bran was determinedaccording the AACC method[12] The method determines the percentage of starchgranules which are susceptible to hydrolysis by amylase Reducing sugars resultingfrom the enzymatic action on damaged starch are measured by ferrycyanide methodand converted to damage starch by using a factor of 0082

RESULT AND DISCUSSION

Proximate compositions and calorific value of dry heat treated and extruded ricebran comparable to raw rice bran are presented in Table 1 From the table it can bereveled that only the crude fat and crude ash contents were affected significantly( plt 005) by the method of stabilization whereas the other constituents and calorificvalue remained almost unchanged after stabilization The extruded rice bran hadsignificantly ( plt 005) higher ash content (862) than did the dry heat treated ricebran (81) A slight increase in ash content after extrusion may be due to thecontamination of extrudates with mineral present in water used in wet extrusionprocessing of bran Crude fat content of extrusion stabilized rice bran wassignificantly ( plt 005) higher than raw rice bran This indicated that stabilization

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Table

1

Effectofmethodofstabilizationontheproxim

ate

compositionandcalorificvalueofrice

bran

Methodsof

stabilization

Crudeprotein

(kg100kgbran)

Crudefat

(kg100kgbran)

Crudefiber

(kg100kgbran)

Crudeash

(kg100kgbran)

Carbohydrates

(kg100kgbran)

Calorificvalue

(KJ100gbran)

RRB

1605

1472

720

840

3972

1486

DHTRB

1590

1506

719

817

3980

1502

ERB

1601

1569

733

862

3995

1504

CD

atP005

NS

0484

NS

022

NS

NS

Data

reported

are

theaverageoftriplicate

determinations

NSNonsignificant

RRBraw

rice

branDHTdry

heattreatedrice

branERBextruded

rice

bran

Physico-Chemical Characteristics of Rice Bran 607

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process of rice bran cause fat cells to coalesce into oil droplets and rapture cellstructure thereby improving the speed of oil extraction[2122] However extrusioncooking appeared to be more effective than the dry heat method and theprocess may have great economic benefits for rice growing region in India Theresults of the proximate compositions of rice bran are in agreement with thosereported by worker[68]

Table 2 displays the effects of method of stabilization on sugars fiber availablelysine and phytic acid contents of rice bran The contents of reducing nonreducingand total sugars remained unaffected and did not differ significantly ( pgt 005) fromraw rice bran It has been reported that starch and nonreducing sugars such assucrose might be degraded during extrusion to form reducing sugars[23] But in thepresent investigation it appeared that the extent of heat processing applied on ricebran was not severe enough to cause this change or some reducing sugars might havebeen formed and took part in the browning reaction as observed from the color ofthe stabilized rice bran which were significantly more than the raw rice bran Theneural detergent fiber (NDF) contents of raw and dry heat treated rice bran didnot differ significantly However after extrusion stabilization the NDF wassignificantly increased Similar effects were observed in gum fiber and total fiberEarlier workers[2425] also reported that neutral detergent fiber increased after heatprocessing due to the formation of compounds which were insoluble in detergentsHeat treatment also exhibited a significant effect on the contents of gum fiberExtrusion stabilized rice bran showed highest content of gum fiber followed bydry heat stabilized rice bran Increased gum fiber in extruded rice bran could bethe result of disruption of covalent and noncovalent bonds of the complexmoeties leading to the formation of more water soluble and alcohol precipitablefragments Almost similar results were also reported by various[26ndash28] researchersAs the contents of NDF and gum fiber increased the increase in total fibercalculated as the sum of NDF and gum fiber was also evident[29] Although somedifferences existed in the fiber constituents of rice bran the values observed in thisstudy were in close agreement with those reported by other workers[830] Thestabilization of rice bran had a significant effect ( plt 005) on lysine responseFDNB-reactive lysine contents of dry heat treated rice bran and extruded rice were369 g and 395 g16 g N compared to 409 g16 g N in raw bran indicating a greaterloss of lysine availability by dry heat method Higher temperature short timeextrusion processing when carried out under wet conditions has been reported to befavorable in terms of lysine retention[31] Heat stabilization of rice bran significantly( plt 005) reduced the phytic acid content of rice bran from 293mgg in raw rice to2650mgg in dry heat treated rice bran and 2466mgg in extruded rice branrespectively Earlier work[3233] showed a significant reduction in phytic acid duringextrusion processing of foods

Functional characteristics of rice bran as summarized in Table 3 showed thatthe bulk density of stabilized rice bran increased significantly ( plt 005) Earlierworkers[2122] also reported similar findings and the higher bulk density of extrudedrice bran was observed to increase percolation rate of the solvent through theextrudates and hence better efficiency of oil extraction

Extruded rice bran had the highest water absorption (1709 g100 g) followed bydry-heat treated rice bran (14378 g100 g) these figure are lower than whereas water

608 Sharma Chauhan and Agrawal

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Table

2

Effectofmethodofstabilizationonsugarandfiber

compoundsavailable

lysine

andphyticacidcontents

ofrice

bran

Methodsof

stabilization

Sugars

Fiber

Available

lysine

g16gN

(notclear)

Phytic

acid

(mgg

bran)

Reducing

sugars

(kg100kg

bran)

Nonreducing

sugars

(kg100kg

bran)

Total

sugars

(kg100kg

bran)

NDF

(kg100kg

bran)

Gum

fiber

(kg100kg

bran)

Total

fiber

(kg100kg

bran)

RRB

090

231

311

2363

095

2458

409

2933

DHTRB

089

212

300

2486

153

2625

369

2450

ERB

087

212

301

272

182

2898

395

2466

CD

atP005

NS

NS

NS

138

023

120

024

295

Data

reported

are

theaverageoftriplicate

determinations

NSNonsignificant

RRBraw

rice

branDHTdry

heattreatedrice

branERBextruded

rice

bran

Physico-Chemical Characteristics of Rice Bran 609

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Table

3

Effectofmethodofstabilizationonthefunctionalcharacteristics

ofrice

Methodsof

stabilization

Bulk

density

(gm

L)

Waterabsorption

(g100g)

Watersolubility

(g100g)

Fatabsorption

(g100g)

Protein

solubility

(g100g)

Damaged

starch

(g100g)

Visual

color

RRB

0500

14368

757

9632

732

082

Lighttan

DHTRB

0548

15691

934

8128

444

325

Brown

ERB

0593

17093

933

7260

303

507

Dark

brown

CD

atP005

0026

3696

0608

2756

0635

0300

mdash

Data

reported

are

theaverageoftriplicate

determinations

RRBraw

rice

branDHTdry

heattreatedrice

branERBextruded

rice

bran

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absorptions in the range of 2131ndash1822 of edible stabilized rice bran as reportedearlier[34] The variation may be attributed to the source of bran and their processing

conditions Similar trend was observed for water solubility Increase in watersolubility of stabilized rice bran may be due to the solubilization of the starchcomponent during heat processing of rice bran by dry heat and extrusion

stabilization A significant decrease in fat absorption characteristics of rice branafter heat treatment was observed which may be due to the changes in bed porosity

and pore size of rice branProtein solubility was highest (732 g100 g ) in raw rice bran and lowest (303)

in extruded rice bran indicating the occurrence of protein denaturation during heatstabilization of rice bran as has been reported earlier[3135] also Heat stabilization

of significantly ( p 005) increased the damaged starch (enzyme susceptible starch)content in rice bran as compared to raw rice bran Result of worker[35] also indicatedhigher content of damaged starch in extruded wheat bran than the raw bran The

formation of damaged starch during extrusionheat processing may be important inyeast fermentation and can act as a functional agent in bran dough[36] Color of the

bran as observed visually extruded bran was dark brown in color whereas the dryheat treated bran was just brown and the raw bran was light tan in color Thechanges in color upon heating may be attributed to the formation of Maillard

reaction compounds during extrusion and partly to the solubilization of colorpigments of raw bran

To evaluate the effectiveness of rice bran stabilization methods (dry heat andextrusion processing) a storage study was carried out The changes in free fatty

acid (FFA) contents recorded during storage are presented in Table 4 Stabilizationmethods and storage period significantly ( plt 005) affected the rate of production offree fatty acids A highly significant increase in FFA was observed in raw rice bran

during storage period FFA content in raw rice bran increased from an initial level of405ndash6460 at 60 days of storage This phenomena is typical of raw rice bran and

results in the development of hydrolytic rancidity in unstabilized rice bran[11] Thishas been attributed to the presence of active inherent lipase system of rice bran whichhydrolyses the oil free fatty acids and glycerol and renders bran unfit for oil

Table 4 Effect of the methods of stabilization and storage period on the development

of free fatty acids (FFAs) in rice bran

Methods of

stabilization

Free fatty acids kg100 kg bran

storage period (days)

0 15 30 45 60

RRB 405 1358 2046 3775 6460

DHTRB 366 375 379 570 915

ERB 385 408 422 420 410

CD at P 005 methods of stabilizationfrac14 0399

CD at P 005 storage periodfrac14 0515

CD at P 005 methods storage periodfrac14 0893

RRB raw rice bran DHT dry heat treated rice bran ERB extruded rice bran

Physico-Chemical Characteristics of Rice Bran 611

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extraction and human consumption Dry heat method of stabilization restricted thedevelopment of FFAs up to 30 days of storage and thereafter a significant increasewas observed This increase in FFAs content of bran may be attributed to thepresence of residual lipolytic activity of enzyme lipase which increased underfavorable conditions during storage Bran might have absorbed some moistureduring storage thereby favoring the lipolytic activity This type of behavior withdry-heat treated rice bran was attributed to the incomplete destruction of lipase bydry heat method and increase in moisture content of rice bran during storage[37]

By extrusion stabilization method the free fatty acid content of rice bran did notincrease significantly ( pgt 005) even at 60 days of storage indicating that theextrusion processing of rice bran is more effective in destroying the lipolytic systemof rice bran than the dry heat method The capability of the extruder in inactivat-ing the fat hydrolyzing enzymes of rice bran has also been reported earlier[911]

Less then 5 FFAs are stated to be desirable in economic refining of oil[38]

Sensory analysis[11] revealed that experienced panelists could not distinguish rancidbran from nonrancid bran until the level of free fatty acids exceeded 15However the level of fatty acids in bran that is considered acceptable for humanconsumption is 4 according to US Standards[8]

CONCLUSION

From the present investigation it can be concluded that the functional propertiessuch as water absorption water solubility bulk density and enzyme susceptiblestarch of rice bran improved significantly after stabilization However the increaseswere more pronounced in extrusion stabilized rice bran On the other hand extrusionstabilized rice bran exhibited lower fat absorption and fat solubility than dryheat stabilized rice bran The improvement in shelf life was also much higher forthe rice bran stabilized by using extrusion technology than by dry heat treatment

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3 Pillaiyar P Rice bran as feed and food The Int J Nutr Dietet 1981 18 1094 Mitsuda H Yasumato K Iwami K Analysis of volatile components in

rice bran Agric Biol Chem 1968 32 4535 Sharma HR Effect of Stabilized Rice Bran and Fenugreek (Trigonella foenum

graecum) Flour on the Physico-Chemical Rheological and BakingCharacteristics of Wheat Flour PhD theses G B Pant University of Agricamp Tech Pant Nagar Pantnagar-263 145 India

6 Luh BS Introduction In Rice Utilization Luh BS Ed AVI PublishingCompany Inc Westport CT 1991 Vol II 1ndash7

612 Sharma Chauhan and Agrawal

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ORDER REPRINTS

7 Slavin JL Lampe JW Health benefits of rice bran in human nutrition

Cereal Foods World 1992 37 7608 Saunders RM Rice bran composition and potential food uses Food Reviews

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Tribelhorn RE Saunders RM Rice bran stabilization by extrusion cooking

for extraction of edible oil Journal of Food Science 1985 50 36110 Desikachar HSR Status Report Preservation of byproducts of rice milling

In Rice Byproducts Preservation Proceedings of Byproducts Utilization

International Conference Valencia Spain Sept 30ndashOct 2 1974 Barber S

Tortosa E Eds Valencia Institute for Agriculture Chemistry and Food

Technology 1977 Vol II 1ndash3211 Martin D Gober JS Selhako G Verma L Wells JH Optimizing rice

bran stabilization by extrusion cooking Lousiana Agraculture 1993 30 1312 AACC Approved Methods of the American Association of Cereal Chemist 8th

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Research 1986 4 38115 Carpenter KJ Corrected straight acids Procedure for determination of

available lysine in foods Biochem Journal 1960 77 60416 Haug W Lantzsch HJ Sensitive method for the determination of phytate

in cereal and cereal products J Sci Food Agric 1983 34 142317 Narain M Siripurapu SCB Jha M Dwiviedi VK Physico-thermal

properties of rice bran J Food Sci Technol 1978 15 1818 Sosuliski FW The centrifuge method for the flour water absorption in hard

red spring wheat Cereal Chem 1962 39 34419 Lin MJ Humbert ES Sosuliski FW Certain functional properties of

sunflower meal products J Food Sci 1974 39 36820 Inklaar PA Fortuin J Determining the emulsifing and emulsion stabilizing

capacity of protein meal additives Food Technology 1969 23 10321 Kim CJ Byun SM Cheigh HS Kwon TW Optimization of extrusion

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extraction characteristics of rice bran pre-treated by hot air drying steam

cooking and extraction J Am Oil Chem Soc 1987b 64 51423 Camire ME Flint SI Thermal processing effects on dietary fiber

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meals Cereal Chem 1991 68 64524 Van Soest PJ Use of detergents in the analysis of fiberous feeds 2 A rapid

method for the determination of fiber and lignin J Assoc Off Anal Chem

1963 66 93325 Matthee V Appledorff H Effect of cooking on vegetable fiber Journal of

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Physico-Chemical Characteristics of Rice Bran 613

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26 Bajorck I Nyman M Asp NG Extrusion cooking and dietary fiber Effectson dietary fiber contents and degradation in the rat intestinal tract CerealChem 1984 57 448

27 Siljestrom M Westerlund E Bjorck I Holm J Asp NG Theander PThe effect of various thermal processes on dietary fiber and starch content ofwhole grain wheat and white flour J Cereal Sci 1986 4 315

28 Aoe S Nakapka M Ido K Tamai Y Ohata F Anano Y Availability ofdietary fiber in extruded wheat bran and apparent digestibility in rates ofcoexisting nutrients Cereal Chem 1989 66 252

29 Theander O Torrie JH Studies on chemical modifications in heat processedstarch and wheat flour StarchStaerke 1987 39 88

30 Babcock D Rice bran as a source of dietary fiber Cereal Foods World 198732 538

31 Cheftel JC Nutritional aspects of extrusion cooking Food Chem 198630 263

32 Chauhan GS Verma NS Bains GS Effect of extrusion process on thenutritional quality of rice legume blend Die Nahrung 1988 32 43

33 Asp NG Bjorck IB Nutritional properties of extruded foods In ExtrusionCooking Mercier C Linko P Harper JM Eds American Association ofCereal Chemists St Paul MN 1989 399ndash434

34 James C Sloan S Functional properties of rice bran in model system Journalof Food Science 1984 49 310

35 Wang WM Klopfestein CF Ponte JG Jr Effects of twin screw extrusionon the physical properties of dietary fiber and other components of wholewheat and wheat bran and on the baking quality of wheat bran Cereal Chem1993 76 707

36 Defloor I De Geest C Schellenkens M Martens A Delour JAEmulsifiers andor extruded starch in the production of bread from cassavaCereal Chem 1991 68 323

37 Loeb JE Mayne RY Effect of moisture on micro flora and formation offree fatty acids in rice bran Cereal Chem 1952 29 163

38 Sayre RN Saunders RM Enochian RV Shultz WG Beagle ECReview of rice bran stabilization systems with emphasis on extrusion cookingCereal Food World 1982 7 317

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whereas extruded bran was stored up to 60 days without any changes in the free

fatty acid content

Key Words Rice bran stabilization Composition Functional properties

Nurtitional properties Storage

INTRODUCTION

Rice is a major food commodity throughout the world India is the largest

producer of rice in the world outside main land of China in productionwise For value

addition low grade rice have been used for extrusion cooking to manufacture

expanded crunchy snacks[1] Based on production the potential availability of rice

bran a by-product of rice milling industry was estimated to be about 5 million metric

tonnes per annum[2] The rice bran refers to the coating removed from brown rice

during the process of milling The bran constitutes nearly 85of the total grain and is

highly nutritious[3] Raw rice bran has ac characteristic bland flavor slightly bitter

and sweet taste Bran flavor is frequently descried as incipient rancid musty and sour

because of its readily deterioration in commercial lots[4] It contains 12ndash25 fat 10ndash

16 protein 10ndash20 starch 3ndash8 reducing sugars 8ndash11 hemicelluloses 10ndash12

celluloses 6ndash15 crude fiber and 65ndash10 ash content Rice bran is abundant in

vitamins of the B group and tocopherols and is poor in vitamins A and C[5] Several

human and animal studies conducted to date suggest that rice bran has interesting

health benefits It appears to be as effective as wheat bran as a laxative aid effective

hypocholesterolmic agent as well as several other health benefits reported in

literature[67] Since rice bran contains less soluble fiber its cholesterol lowering and

other health enhancing properties may be related to associated compounds These

include rice bran oil plant sterols tocopherols oryzanol and b-sitosterol[8] Although

the nutritional and food potential of rice bran have been recognized the consumption

of rice bran in human foods has been limited to a very small quantity This may be

partially due to the result of lipid deterioration by the enzymes such as lipase growth

inhibitors microorganisms and insects in rice bran[6] Several types of heat

stabilization procedures have been mentioned which involve the application of dry

or moist heat treatments for a sufficient time to arrest the activity of spoilage agencies

such as lipases and destroy the antinutritional factors[9] Baked foods provide one of

the most potential possibilities of utilizing rice bran in foods Uses of rice bran are

advocated in making breads muffins pan cakes cookies cakes pies extruded

snacks and breakfast cereals The stabilization of rice bran by using extrusion

cooking and dry heat treatment is practical and has the commercial potential

therefore these two method of stabilization were compared[10] The stabilization of

rice bran has been reported to improve nutritional functional and keeping quality of

rice bran[11] Considering the nutritional and food potential and associated health

benefits of consuming rice bran the present investigation was planned to compare the

effects of dry heat treatment with that of extrusion cooking on the physico-chemical

characteristics of rice bran and their stability during storage

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MATERIALS AND METHODS

Fresh rice bran was procured from MS Shakti Rice Mills Rudurpur (UA)India Rice bran was stabilized immediately after procurement using dry-heat andextrusion cooking as described below

Dry Heat Stabilization

Rice bran was transferred to open shallow pans and spreaded uniformly in thinlayers The pans were then placed in the oven maintained at 120C and dried for30min The dried bran was ground to pass through screen (032mm) of the Fitz(Fitz company USA) mill to produce particle size close to wheat flour The branwas stored at an ambient temperature in polyethylene bags for further use

Extrusion Stabilization

It was preformed using a Wenger X-5 Laboratory Extruder (Wenger Mfg CoSabetha KS USA) with the following conditions Water flow rate 0000038m3sfeed rate 27 kghr steam supply 27580 kPa die opening 00078m temperature135ndash140C Extrudates were air dried at 50C for 24 h and ground in a Fitz Millto pass through 032mm screen of the mill as in dry heat method The bran wasstored at an ambient temperature in polyethylene bags for further use

Chemical Composition

The samples of bran were analyzed for moisture protein (N 595) crude fattotal ash crude fibre calcium and sugars according to AACC[12] methods Thepercent values of moisture protein fat ash and crude fiber were subtracted from100 and the remainder was expressed as carbohydrates (by difference) Calorificvalue (kJ100 g) was calculated from the physiological fuel values of protein fatand carbohydrates While the color of different bran samples was noted visuallyNeutral detergent fiber was determined according the method described by theworker[13] The method is based on the extraction of the food with hot neutraldetergent solution The residues (NDF) contain lignin cellulose hemicellulose andcell wall protein

Gum fiber was determined according to the procedure described by Sharma[14]

One gram sample was extracted with 25mL of acetic acid solution by stirring atroom temperature for 30min The contents were centrifuged for 20min at 6500 rpmand the supernatant recovered The process of extraction and centrifugation wasrepeated four times and supernatants were pooled Gum was precipitated frompooled acetic acid extract by the addition of ethanol with stirring till 50concentration of ethanol was reached The suspension was centrifuged and thesupernatants were decanted The precipitate was again washed with ethanol andacetone and dried at 50C to a constant weight Total fiber was roughly calculated

Physico-Chemical Characteristics of Rice Bran 605

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as the sum of neutral detergent fiber and gum fiber according to the methoddescribed by worker[14]

Available lysine was determined by Carpenter method[15] which is based on thereaction of fluorodinitrobenzene (FDNB) with the epsilon-NH2 group of lysine inthe proteins and the colorimetric determination of the DNP-lysine obtained bysubsequent acid hydrolysis Method of Haug and Lantzsch[16] was used to estimatethe phytic acid content in rice bran sample In this method sample extract washeated with acidic iron (ferric) solution of a known iron content The decrease in iron(determined colorimetrically with 2ndash2 bipyridine) in supernatant is a measure ofphytic acid content Free fatty acid contents of raw and stabilized rice bran weredetermined by AACC method[12]

Functional Characteristics

Bulk density of raw and stabilized bran were determined by method ofNarain et al[17] Water absorption capacities of raw and stabilized rice bran weremeasured by a modified method reported by Sosuliski[18] Sample of 25 g wasdispersed with 25mL of water in a 50mL centrifuge tube and allowed the mixtureto stand for 15min at 25C then centrifuged the sample at 3200 rpm for 15minThe amount of water retained by the solids was measured Fat absorption of ricebran were estimated by mixing 5 g sample with 50mL corn oil allowing the mixtureto stand for 15min at room temperature and then centrifuging at 3200 rpm for15min The fat retained by the solids was measured[19]

Fortuin method[20] was followed to determine the protein solubility of branWeighed sample (25 g) was dispersed in 100mL distilled water and stirred for 1 h ata controlled temperature of 50C The solution was then centrifuged for 30min at3200 rpm The supernatant was collected in a flask and the nitrogen content wasdetermined by Kjeldahl method[12] Damaged starch in rice bran was determinedaccording the AACC method[12] The method determines the percentage of starchgranules which are susceptible to hydrolysis by amylase Reducing sugars resultingfrom the enzymatic action on damaged starch are measured by ferrycyanide methodand converted to damage starch by using a factor of 0082

RESULT AND DISCUSSION

Proximate compositions and calorific value of dry heat treated and extruded ricebran comparable to raw rice bran are presented in Table 1 From the table it can bereveled that only the crude fat and crude ash contents were affected significantly( plt 005) by the method of stabilization whereas the other constituents and calorificvalue remained almost unchanged after stabilization The extruded rice bran hadsignificantly ( plt 005) higher ash content (862) than did the dry heat treated ricebran (81) A slight increase in ash content after extrusion may be due to thecontamination of extrudates with mineral present in water used in wet extrusionprocessing of bran Crude fat content of extrusion stabilized rice bran wassignificantly ( plt 005) higher than raw rice bran This indicated that stabilization

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Table

1

Effectofmethodofstabilizationontheproxim

ate

compositionandcalorificvalueofrice

bran

Methodsof

stabilization

Crudeprotein

(kg100kgbran)

Crudefat

(kg100kgbran)

Crudefiber

(kg100kgbran)

Crudeash

(kg100kgbran)

Carbohydrates

(kg100kgbran)

Calorificvalue

(KJ100gbran)

RRB

1605

1472

720

840

3972

1486

DHTRB

1590

1506

719

817

3980

1502

ERB

1601

1569

733

862

3995

1504

CD

atP005

NS

0484

NS

022

NS

NS

Data

reported

are

theaverageoftriplicate

determinations

NSNonsignificant

RRBraw

rice

branDHTdry

heattreatedrice

branERBextruded

rice

bran

Physico-Chemical Characteristics of Rice Bran 607

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process of rice bran cause fat cells to coalesce into oil droplets and rapture cellstructure thereby improving the speed of oil extraction[2122] However extrusioncooking appeared to be more effective than the dry heat method and theprocess may have great economic benefits for rice growing region in India Theresults of the proximate compositions of rice bran are in agreement with thosereported by worker[68]

Table 2 displays the effects of method of stabilization on sugars fiber availablelysine and phytic acid contents of rice bran The contents of reducing nonreducingand total sugars remained unaffected and did not differ significantly ( pgt 005) fromraw rice bran It has been reported that starch and nonreducing sugars such assucrose might be degraded during extrusion to form reducing sugars[23] But in thepresent investigation it appeared that the extent of heat processing applied on ricebran was not severe enough to cause this change or some reducing sugars might havebeen formed and took part in the browning reaction as observed from the color ofthe stabilized rice bran which were significantly more than the raw rice bran Theneural detergent fiber (NDF) contents of raw and dry heat treated rice bran didnot differ significantly However after extrusion stabilization the NDF wassignificantly increased Similar effects were observed in gum fiber and total fiberEarlier workers[2425] also reported that neutral detergent fiber increased after heatprocessing due to the formation of compounds which were insoluble in detergentsHeat treatment also exhibited a significant effect on the contents of gum fiberExtrusion stabilized rice bran showed highest content of gum fiber followed bydry heat stabilized rice bran Increased gum fiber in extruded rice bran could bethe result of disruption of covalent and noncovalent bonds of the complexmoeties leading to the formation of more water soluble and alcohol precipitablefragments Almost similar results were also reported by various[26ndash28] researchersAs the contents of NDF and gum fiber increased the increase in total fibercalculated as the sum of NDF and gum fiber was also evident[29] Although somedifferences existed in the fiber constituents of rice bran the values observed in thisstudy were in close agreement with those reported by other workers[830] Thestabilization of rice bran had a significant effect ( plt 005) on lysine responseFDNB-reactive lysine contents of dry heat treated rice bran and extruded rice were369 g and 395 g16 g N compared to 409 g16 g N in raw bran indicating a greaterloss of lysine availability by dry heat method Higher temperature short timeextrusion processing when carried out under wet conditions has been reported to befavorable in terms of lysine retention[31] Heat stabilization of rice bran significantly( plt 005) reduced the phytic acid content of rice bran from 293mgg in raw rice to2650mgg in dry heat treated rice bran and 2466mgg in extruded rice branrespectively Earlier work[3233] showed a significant reduction in phytic acid duringextrusion processing of foods

Functional characteristics of rice bran as summarized in Table 3 showed thatthe bulk density of stabilized rice bran increased significantly ( plt 005) Earlierworkers[2122] also reported similar findings and the higher bulk density of extrudedrice bran was observed to increase percolation rate of the solvent through theextrudates and hence better efficiency of oil extraction

Extruded rice bran had the highest water absorption (1709 g100 g) followed bydry-heat treated rice bran (14378 g100 g) these figure are lower than whereas water

608 Sharma Chauhan and Agrawal

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Table

2

Effectofmethodofstabilizationonsugarandfiber

compoundsavailable

lysine

andphyticacidcontents

ofrice

bran

Methodsof

stabilization

Sugars

Fiber

Available

lysine

g16gN

(notclear)

Phytic

acid

(mgg

bran)

Reducing

sugars

(kg100kg

bran)

Nonreducing

sugars

(kg100kg

bran)

Total

sugars

(kg100kg

bran)

NDF

(kg100kg

bran)

Gum

fiber

(kg100kg

bran)

Total

fiber

(kg100kg

bran)

RRB

090

231

311

2363

095

2458

409

2933

DHTRB

089

212

300

2486

153

2625

369

2450

ERB

087

212

301

272

182

2898

395

2466

CD

atP005

NS

NS

NS

138

023

120

024

295

Data

reported

are

theaverageoftriplicate

determinations

NSNonsignificant

RRBraw

rice

branDHTdry

heattreatedrice

branERBextruded

rice

bran

Physico-Chemical Characteristics of Rice Bran 609

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Table

3

Effectofmethodofstabilizationonthefunctionalcharacteristics

ofrice

Methodsof

stabilization

Bulk

density

(gm

L)

Waterabsorption

(g100g)

Watersolubility

(g100g)

Fatabsorption

(g100g)

Protein

solubility

(g100g)

Damaged

starch

(g100g)

Visual

color

RRB

0500

14368

757

9632

732

082

Lighttan

DHTRB

0548

15691

934

8128

444

325

Brown

ERB

0593

17093

933

7260

303

507

Dark

brown

CD

atP005

0026

3696

0608

2756

0635

0300

mdash

Data

reported

are

theaverageoftriplicate

determinations

RRBraw

rice

branDHTdry

heattreatedrice

branERBextruded

rice

bran

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absorptions in the range of 2131ndash1822 of edible stabilized rice bran as reportedearlier[34] The variation may be attributed to the source of bran and their processing

conditions Similar trend was observed for water solubility Increase in watersolubility of stabilized rice bran may be due to the solubilization of the starchcomponent during heat processing of rice bran by dry heat and extrusion

stabilization A significant decrease in fat absorption characteristics of rice branafter heat treatment was observed which may be due to the changes in bed porosity

and pore size of rice branProtein solubility was highest (732 g100 g ) in raw rice bran and lowest (303)

in extruded rice bran indicating the occurrence of protein denaturation during heatstabilization of rice bran as has been reported earlier[3135] also Heat stabilization

of significantly ( p 005) increased the damaged starch (enzyme susceptible starch)content in rice bran as compared to raw rice bran Result of worker[35] also indicatedhigher content of damaged starch in extruded wheat bran than the raw bran The

formation of damaged starch during extrusionheat processing may be important inyeast fermentation and can act as a functional agent in bran dough[36] Color of the

bran as observed visually extruded bran was dark brown in color whereas the dryheat treated bran was just brown and the raw bran was light tan in color Thechanges in color upon heating may be attributed to the formation of Maillard

reaction compounds during extrusion and partly to the solubilization of colorpigments of raw bran

To evaluate the effectiveness of rice bran stabilization methods (dry heat andextrusion processing) a storage study was carried out The changes in free fatty

acid (FFA) contents recorded during storage are presented in Table 4 Stabilizationmethods and storage period significantly ( plt 005) affected the rate of production offree fatty acids A highly significant increase in FFA was observed in raw rice bran

during storage period FFA content in raw rice bran increased from an initial level of405ndash6460 at 60 days of storage This phenomena is typical of raw rice bran and

results in the development of hydrolytic rancidity in unstabilized rice bran[11] Thishas been attributed to the presence of active inherent lipase system of rice bran whichhydrolyses the oil free fatty acids and glycerol and renders bran unfit for oil

Table 4 Effect of the methods of stabilization and storage period on the development

of free fatty acids (FFAs) in rice bran

Methods of

stabilization

Free fatty acids kg100 kg bran

storage period (days)

0 15 30 45 60

RRB 405 1358 2046 3775 6460

DHTRB 366 375 379 570 915

ERB 385 408 422 420 410

CD at P 005 methods of stabilizationfrac14 0399

CD at P 005 storage periodfrac14 0515

CD at P 005 methods storage periodfrac14 0893

RRB raw rice bran DHT dry heat treated rice bran ERB extruded rice bran

Physico-Chemical Characteristics of Rice Bran 611

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extraction and human consumption Dry heat method of stabilization restricted thedevelopment of FFAs up to 30 days of storage and thereafter a significant increasewas observed This increase in FFAs content of bran may be attributed to thepresence of residual lipolytic activity of enzyme lipase which increased underfavorable conditions during storage Bran might have absorbed some moistureduring storage thereby favoring the lipolytic activity This type of behavior withdry-heat treated rice bran was attributed to the incomplete destruction of lipase bydry heat method and increase in moisture content of rice bran during storage[37]

By extrusion stabilization method the free fatty acid content of rice bran did notincrease significantly ( pgt 005) even at 60 days of storage indicating that theextrusion processing of rice bran is more effective in destroying the lipolytic systemof rice bran than the dry heat method The capability of the extruder in inactivat-ing the fat hydrolyzing enzymes of rice bran has also been reported earlier[911]

Less then 5 FFAs are stated to be desirable in economic refining of oil[38]

Sensory analysis[11] revealed that experienced panelists could not distinguish rancidbran from nonrancid bran until the level of free fatty acids exceeded 15However the level of fatty acids in bran that is considered acceptable for humanconsumption is 4 according to US Standards[8]

CONCLUSION

From the present investigation it can be concluded that the functional propertiessuch as water absorption water solubility bulk density and enzyme susceptiblestarch of rice bran improved significantly after stabilization However the increaseswere more pronounced in extrusion stabilized rice bran On the other hand extrusionstabilized rice bran exhibited lower fat absorption and fat solubility than dryheat stabilized rice bran The improvement in shelf life was also much higher forthe rice bran stabilized by using extrusion technology than by dry heat treatment

REFERENCES

1 Gujral HS Singh N Extrusion behavior and product characteristics of brawnand milled rice grits International Journal of Food Properties 2002 5 307

2 Gupta HP Rice bran offers India and oil source J Am Oil Chem Soc 198966 (1) 62

3 Pillaiyar P Rice bran as feed and food The Int J Nutr Dietet 1981 18 1094 Mitsuda H Yasumato K Iwami K Analysis of volatile components in

rice bran Agric Biol Chem 1968 32 4535 Sharma HR Effect of Stabilized Rice Bran and Fenugreek (Trigonella foenum

graecum) Flour on the Physico-Chemical Rheological and BakingCharacteristics of Wheat Flour PhD theses G B Pant University of Agricamp Tech Pant Nagar Pantnagar-263 145 India

6 Luh BS Introduction In Rice Utilization Luh BS Ed AVI PublishingCompany Inc Westport CT 1991 Vol II 1ndash7

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7 Slavin JL Lampe JW Health benefits of rice bran in human nutrition

Cereal Foods World 1992 37 7608 Saunders RM Rice bran composition and potential food uses Food Reviews

International 1986 1 4659 Randall JM Sayre RN Schultz WG Fong RY Mossman AP

Tribelhorn RE Saunders RM Rice bran stabilization by extrusion cooking

for extraction of edible oil Journal of Food Science 1985 50 36110 Desikachar HSR Status Report Preservation of byproducts of rice milling

In Rice Byproducts Preservation Proceedings of Byproducts Utilization

International Conference Valencia Spain Sept 30ndashOct 2 1974 Barber S

Tortosa E Eds Valencia Institute for Agriculture Chemistry and Food

Technology 1977 Vol II 1ndash3211 Martin D Gober JS Selhako G Verma L Wells JH Optimizing rice

bran stabilization by extrusion cooking Lousiana Agraculture 1993 30 1312 AACC Approved Methods of the American Association of Cereal Chemist 8th

Ed The Association St Paul MN 198313 Goering HK Soest PJ Forage fiber analysis (apparatus reagent processing

and some applications) Agriculture Handbook No 379 Agricultural Research

Series United States Department of Agriculture 1970 11214 Sharma RD Hypocholesterolemic activity of some Indian gums Nutrition

Research 1986 4 38115 Carpenter KJ Corrected straight acids Procedure for determination of

available lysine in foods Biochem Journal 1960 77 60416 Haug W Lantzsch HJ Sensitive method for the determination of phytate

in cereal and cereal products J Sci Food Agric 1983 34 142317 Narain M Siripurapu SCB Jha M Dwiviedi VK Physico-thermal

properties of rice bran J Food Sci Technol 1978 15 1818 Sosuliski FW The centrifuge method for the flour water absorption in hard

red spring wheat Cereal Chem 1962 39 34419 Lin MJ Humbert ES Sosuliski FW Certain functional properties of

sunflower meal products J Food Sci 1974 39 36820 Inklaar PA Fortuin J Determining the emulsifing and emulsion stabilizing

capacity of protein meal additives Food Technology 1969 23 10321 Kim CJ Byun SM Cheigh HS Kwon TW Optimization of extrusion

bran stabilization process Journal of Food Science 1987a 52 135522 Kim CJ Byun SM Cheigh HS Kwon TW Compression of solvent

extraction characteristics of rice bran pre-treated by hot air drying steam

cooking and extraction J Am Oil Chem Soc 1987b 64 51423 Camire ME Flint SI Thermal processing effects on dietary fiber

composition and hydration capacity in corn meal oat meal and potato

meals Cereal Chem 1991 68 64524 Van Soest PJ Use of detergents in the analysis of fiberous feeds 2 A rapid

method for the determination of fiber and lignin J Assoc Off Anal Chem

1963 66 93325 Matthee V Appledorff H Effect of cooking on vegetable fiber Journal of

Food Sciences 1978 43 1344

Physico-Chemical Characteristics of Rice Bran 613

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26 Bajorck I Nyman M Asp NG Extrusion cooking and dietary fiber Effectson dietary fiber contents and degradation in the rat intestinal tract CerealChem 1984 57 448

27 Siljestrom M Westerlund E Bjorck I Holm J Asp NG Theander PThe effect of various thermal processes on dietary fiber and starch content ofwhole grain wheat and white flour J Cereal Sci 1986 4 315

28 Aoe S Nakapka M Ido K Tamai Y Ohata F Anano Y Availability ofdietary fiber in extruded wheat bran and apparent digestibility in rates ofcoexisting nutrients Cereal Chem 1989 66 252

29 Theander O Torrie JH Studies on chemical modifications in heat processedstarch and wheat flour StarchStaerke 1987 39 88

30 Babcock D Rice bran as a source of dietary fiber Cereal Foods World 198732 538

31 Cheftel JC Nutritional aspects of extrusion cooking Food Chem 198630 263

32 Chauhan GS Verma NS Bains GS Effect of extrusion process on thenutritional quality of rice legume blend Die Nahrung 1988 32 43

33 Asp NG Bjorck IB Nutritional properties of extruded foods In ExtrusionCooking Mercier C Linko P Harper JM Eds American Association ofCereal Chemists St Paul MN 1989 399ndash434

34 James C Sloan S Functional properties of rice bran in model system Journalof Food Science 1984 49 310

35 Wang WM Klopfestein CF Ponte JG Jr Effects of twin screw extrusionon the physical properties of dietary fiber and other components of wholewheat and wheat bran and on the baking quality of wheat bran Cereal Chem1993 76 707

36 Defloor I De Geest C Schellenkens M Martens A Delour JAEmulsifiers andor extruded starch in the production of bread from cassavaCereal Chem 1991 68 323

37 Loeb JE Mayne RY Effect of moisture on micro flora and formation offree fatty acids in rice bran Cereal Chem 1952 29 163

38 Sayre RN Saunders RM Enochian RV Shultz WG Beagle ECReview of rice bran stabilization systems with emphasis on extrusion cookingCereal Food World 1982 7 317

614 Sharma Chauhan and Agrawal

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Get permission to lawfully reproduce and distribute the Materials or order reprints quickly and painlessly Simply click on the Request Permission Order Reprints link below and follow the instructions Visit the US Copyright Office for information on Fair Use limitations of US copyright law Please refer to The Association of American Publishersrsquo (AAP) website for guidelines on Fair Use in the Classroom

The Materials are for your personal use only and cannot be reformatted reposted resold or distributed by electronic means or otherwise without permission from Marcel Dekker Inc Marcel Dekker Inc grants you the limited right to display the Materials only on your personal computer or personal wireless device and to copy and download single copies of such Materials provided that any copyright trademark or other notice appearing on such Materials is also retained by displayed copied or downloaded as part of the Materials and is not removed or obscured and provided you do not edit modify alter or enhance the Materials Please refer to our Website User Agreement for more details

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ORDER REPRINTS

MATERIALS AND METHODS

Fresh rice bran was procured from MS Shakti Rice Mills Rudurpur (UA)India Rice bran was stabilized immediately after procurement using dry-heat andextrusion cooking as described below

Dry Heat Stabilization

Rice bran was transferred to open shallow pans and spreaded uniformly in thinlayers The pans were then placed in the oven maintained at 120C and dried for30min The dried bran was ground to pass through screen (032mm) of the Fitz(Fitz company USA) mill to produce particle size close to wheat flour The branwas stored at an ambient temperature in polyethylene bags for further use

Extrusion Stabilization

It was preformed using a Wenger X-5 Laboratory Extruder (Wenger Mfg CoSabetha KS USA) with the following conditions Water flow rate 0000038m3sfeed rate 27 kghr steam supply 27580 kPa die opening 00078m temperature135ndash140C Extrudates were air dried at 50C for 24 h and ground in a Fitz Millto pass through 032mm screen of the mill as in dry heat method The bran wasstored at an ambient temperature in polyethylene bags for further use

Chemical Composition

The samples of bran were analyzed for moisture protein (N 595) crude fattotal ash crude fibre calcium and sugars according to AACC[12] methods Thepercent values of moisture protein fat ash and crude fiber were subtracted from100 and the remainder was expressed as carbohydrates (by difference) Calorificvalue (kJ100 g) was calculated from the physiological fuel values of protein fatand carbohydrates While the color of different bran samples was noted visuallyNeutral detergent fiber was determined according the method described by theworker[13] The method is based on the extraction of the food with hot neutraldetergent solution The residues (NDF) contain lignin cellulose hemicellulose andcell wall protein

Gum fiber was determined according to the procedure described by Sharma[14]

One gram sample was extracted with 25mL of acetic acid solution by stirring atroom temperature for 30min The contents were centrifuged for 20min at 6500 rpmand the supernatant recovered The process of extraction and centrifugation wasrepeated four times and supernatants were pooled Gum was precipitated frompooled acetic acid extract by the addition of ethanol with stirring till 50concentration of ethanol was reached The suspension was centrifuged and thesupernatants were decanted The precipitate was again washed with ethanol andacetone and dried at 50C to a constant weight Total fiber was roughly calculated

Physico-Chemical Characteristics of Rice Bran 605

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as the sum of neutral detergent fiber and gum fiber according to the methoddescribed by worker[14]

Available lysine was determined by Carpenter method[15] which is based on thereaction of fluorodinitrobenzene (FDNB) with the epsilon-NH2 group of lysine inthe proteins and the colorimetric determination of the DNP-lysine obtained bysubsequent acid hydrolysis Method of Haug and Lantzsch[16] was used to estimatethe phytic acid content in rice bran sample In this method sample extract washeated with acidic iron (ferric) solution of a known iron content The decrease in iron(determined colorimetrically with 2ndash2 bipyridine) in supernatant is a measure ofphytic acid content Free fatty acid contents of raw and stabilized rice bran weredetermined by AACC method[12]

Functional Characteristics

Bulk density of raw and stabilized bran were determined by method ofNarain et al[17] Water absorption capacities of raw and stabilized rice bran weremeasured by a modified method reported by Sosuliski[18] Sample of 25 g wasdispersed with 25mL of water in a 50mL centrifuge tube and allowed the mixtureto stand for 15min at 25C then centrifuged the sample at 3200 rpm for 15minThe amount of water retained by the solids was measured Fat absorption of ricebran were estimated by mixing 5 g sample with 50mL corn oil allowing the mixtureto stand for 15min at room temperature and then centrifuging at 3200 rpm for15min The fat retained by the solids was measured[19]

Fortuin method[20] was followed to determine the protein solubility of branWeighed sample (25 g) was dispersed in 100mL distilled water and stirred for 1 h ata controlled temperature of 50C The solution was then centrifuged for 30min at3200 rpm The supernatant was collected in a flask and the nitrogen content wasdetermined by Kjeldahl method[12] Damaged starch in rice bran was determinedaccording the AACC method[12] The method determines the percentage of starchgranules which are susceptible to hydrolysis by amylase Reducing sugars resultingfrom the enzymatic action on damaged starch are measured by ferrycyanide methodand converted to damage starch by using a factor of 0082

RESULT AND DISCUSSION

Proximate compositions and calorific value of dry heat treated and extruded ricebran comparable to raw rice bran are presented in Table 1 From the table it can bereveled that only the crude fat and crude ash contents were affected significantly( plt 005) by the method of stabilization whereas the other constituents and calorificvalue remained almost unchanged after stabilization The extruded rice bran hadsignificantly ( plt 005) higher ash content (862) than did the dry heat treated ricebran (81) A slight increase in ash content after extrusion may be due to thecontamination of extrudates with mineral present in water used in wet extrusionprocessing of bran Crude fat content of extrusion stabilized rice bran wassignificantly ( plt 005) higher than raw rice bran This indicated that stabilization

606 Sharma Chauhan and Agrawal

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Table

1

Effectofmethodofstabilizationontheproxim

ate

compositionandcalorificvalueofrice

bran

Methodsof

stabilization

Crudeprotein

(kg100kgbran)

Crudefat

(kg100kgbran)

Crudefiber

(kg100kgbran)

Crudeash

(kg100kgbran)

Carbohydrates

(kg100kgbran)

Calorificvalue

(KJ100gbran)

RRB

1605

1472

720

840

3972

1486

DHTRB

1590

1506

719

817

3980

1502

ERB

1601

1569

733

862

3995

1504

CD

atP005

NS

0484

NS

022

NS

NS

Data

reported

are

theaverageoftriplicate

determinations

NSNonsignificant

RRBraw

rice

branDHTdry

heattreatedrice

branERBextruded

rice

bran

Physico-Chemical Characteristics of Rice Bran 607

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process of rice bran cause fat cells to coalesce into oil droplets and rapture cellstructure thereby improving the speed of oil extraction[2122] However extrusioncooking appeared to be more effective than the dry heat method and theprocess may have great economic benefits for rice growing region in India Theresults of the proximate compositions of rice bran are in agreement with thosereported by worker[68]

Table 2 displays the effects of method of stabilization on sugars fiber availablelysine and phytic acid contents of rice bran The contents of reducing nonreducingand total sugars remained unaffected and did not differ significantly ( pgt 005) fromraw rice bran It has been reported that starch and nonreducing sugars such assucrose might be degraded during extrusion to form reducing sugars[23] But in thepresent investigation it appeared that the extent of heat processing applied on ricebran was not severe enough to cause this change or some reducing sugars might havebeen formed and took part in the browning reaction as observed from the color ofthe stabilized rice bran which were significantly more than the raw rice bran Theneural detergent fiber (NDF) contents of raw and dry heat treated rice bran didnot differ significantly However after extrusion stabilization the NDF wassignificantly increased Similar effects were observed in gum fiber and total fiberEarlier workers[2425] also reported that neutral detergent fiber increased after heatprocessing due to the formation of compounds which were insoluble in detergentsHeat treatment also exhibited a significant effect on the contents of gum fiberExtrusion stabilized rice bran showed highest content of gum fiber followed bydry heat stabilized rice bran Increased gum fiber in extruded rice bran could bethe result of disruption of covalent and noncovalent bonds of the complexmoeties leading to the formation of more water soluble and alcohol precipitablefragments Almost similar results were also reported by various[26ndash28] researchersAs the contents of NDF and gum fiber increased the increase in total fibercalculated as the sum of NDF and gum fiber was also evident[29] Although somedifferences existed in the fiber constituents of rice bran the values observed in thisstudy were in close agreement with those reported by other workers[830] Thestabilization of rice bran had a significant effect ( plt 005) on lysine responseFDNB-reactive lysine contents of dry heat treated rice bran and extruded rice were369 g and 395 g16 g N compared to 409 g16 g N in raw bran indicating a greaterloss of lysine availability by dry heat method Higher temperature short timeextrusion processing when carried out under wet conditions has been reported to befavorable in terms of lysine retention[31] Heat stabilization of rice bran significantly( plt 005) reduced the phytic acid content of rice bran from 293mgg in raw rice to2650mgg in dry heat treated rice bran and 2466mgg in extruded rice branrespectively Earlier work[3233] showed a significant reduction in phytic acid duringextrusion processing of foods

Functional characteristics of rice bran as summarized in Table 3 showed thatthe bulk density of stabilized rice bran increased significantly ( plt 005) Earlierworkers[2122] also reported similar findings and the higher bulk density of extrudedrice bran was observed to increase percolation rate of the solvent through theextrudates and hence better efficiency of oil extraction

Extruded rice bran had the highest water absorption (1709 g100 g) followed bydry-heat treated rice bran (14378 g100 g) these figure are lower than whereas water

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Table

2

Effectofmethodofstabilizationonsugarandfiber

compoundsavailable

lysine

andphyticacidcontents

ofrice

bran

Methodsof

stabilization

Sugars

Fiber

Available

lysine

g16gN

(notclear)

Phytic

acid

(mgg

bran)

Reducing

sugars

(kg100kg

bran)

Nonreducing

sugars

(kg100kg

bran)

Total

sugars

(kg100kg

bran)

NDF

(kg100kg

bran)

Gum

fiber

(kg100kg

bran)

Total

fiber

(kg100kg

bran)

RRB

090

231

311

2363

095

2458

409

2933

DHTRB

089

212

300

2486

153

2625

369

2450

ERB

087

212

301

272

182

2898

395

2466

CD

atP005

NS

NS

NS

138

023

120

024

295

Data

reported

are

theaverageoftriplicate

determinations

NSNonsignificant

RRBraw

rice

branDHTdry

heattreatedrice

branERBextruded

rice

bran

Physico-Chemical Characteristics of Rice Bran 609

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Table

3

Effectofmethodofstabilizationonthefunctionalcharacteristics

ofrice

Methodsof

stabilization

Bulk

density

(gm

L)

Waterabsorption

(g100g)

Watersolubility

(g100g)

Fatabsorption

(g100g)

Protein

solubility

(g100g)

Damaged

starch

(g100g)

Visual

color

RRB

0500

14368

757

9632

732

082

Lighttan

DHTRB

0548

15691

934

8128

444

325

Brown

ERB

0593

17093

933

7260

303

507

Dark

brown

CD

atP005

0026

3696

0608

2756

0635

0300

mdash

Data

reported

are

theaverageoftriplicate

determinations

RRBraw

rice

branDHTdry

heattreatedrice

branERBextruded

rice

bran

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absorptions in the range of 2131ndash1822 of edible stabilized rice bran as reportedearlier[34] The variation may be attributed to the source of bran and their processing

conditions Similar trend was observed for water solubility Increase in watersolubility of stabilized rice bran may be due to the solubilization of the starchcomponent during heat processing of rice bran by dry heat and extrusion

stabilization A significant decrease in fat absorption characteristics of rice branafter heat treatment was observed which may be due to the changes in bed porosity

and pore size of rice branProtein solubility was highest (732 g100 g ) in raw rice bran and lowest (303)

in extruded rice bran indicating the occurrence of protein denaturation during heatstabilization of rice bran as has been reported earlier[3135] also Heat stabilization

of significantly ( p 005) increased the damaged starch (enzyme susceptible starch)content in rice bran as compared to raw rice bran Result of worker[35] also indicatedhigher content of damaged starch in extruded wheat bran than the raw bran The

formation of damaged starch during extrusionheat processing may be important inyeast fermentation and can act as a functional agent in bran dough[36] Color of the

bran as observed visually extruded bran was dark brown in color whereas the dryheat treated bran was just brown and the raw bran was light tan in color Thechanges in color upon heating may be attributed to the formation of Maillard

reaction compounds during extrusion and partly to the solubilization of colorpigments of raw bran

To evaluate the effectiveness of rice bran stabilization methods (dry heat andextrusion processing) a storage study was carried out The changes in free fatty

acid (FFA) contents recorded during storage are presented in Table 4 Stabilizationmethods and storage period significantly ( plt 005) affected the rate of production offree fatty acids A highly significant increase in FFA was observed in raw rice bran

during storage period FFA content in raw rice bran increased from an initial level of405ndash6460 at 60 days of storage This phenomena is typical of raw rice bran and

results in the development of hydrolytic rancidity in unstabilized rice bran[11] Thishas been attributed to the presence of active inherent lipase system of rice bran whichhydrolyses the oil free fatty acids and glycerol and renders bran unfit for oil

Table 4 Effect of the methods of stabilization and storage period on the development

of free fatty acids (FFAs) in rice bran

Methods of

stabilization

Free fatty acids kg100 kg bran

storage period (days)

0 15 30 45 60

RRB 405 1358 2046 3775 6460

DHTRB 366 375 379 570 915

ERB 385 408 422 420 410

CD at P 005 methods of stabilizationfrac14 0399

CD at P 005 storage periodfrac14 0515

CD at P 005 methods storage periodfrac14 0893

RRB raw rice bran DHT dry heat treated rice bran ERB extruded rice bran

Physico-Chemical Characteristics of Rice Bran 611

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extraction and human consumption Dry heat method of stabilization restricted thedevelopment of FFAs up to 30 days of storage and thereafter a significant increasewas observed This increase in FFAs content of bran may be attributed to thepresence of residual lipolytic activity of enzyme lipase which increased underfavorable conditions during storage Bran might have absorbed some moistureduring storage thereby favoring the lipolytic activity This type of behavior withdry-heat treated rice bran was attributed to the incomplete destruction of lipase bydry heat method and increase in moisture content of rice bran during storage[37]

By extrusion stabilization method the free fatty acid content of rice bran did notincrease significantly ( pgt 005) even at 60 days of storage indicating that theextrusion processing of rice bran is more effective in destroying the lipolytic systemof rice bran than the dry heat method The capability of the extruder in inactivat-ing the fat hydrolyzing enzymes of rice bran has also been reported earlier[911]

Less then 5 FFAs are stated to be desirable in economic refining of oil[38]

Sensory analysis[11] revealed that experienced panelists could not distinguish rancidbran from nonrancid bran until the level of free fatty acids exceeded 15However the level of fatty acids in bran that is considered acceptable for humanconsumption is 4 according to US Standards[8]

CONCLUSION

From the present investigation it can be concluded that the functional propertiessuch as water absorption water solubility bulk density and enzyme susceptiblestarch of rice bran improved significantly after stabilization However the increaseswere more pronounced in extrusion stabilized rice bran On the other hand extrusionstabilized rice bran exhibited lower fat absorption and fat solubility than dryheat stabilized rice bran The improvement in shelf life was also much higher forthe rice bran stabilized by using extrusion technology than by dry heat treatment

REFERENCES

1 Gujral HS Singh N Extrusion behavior and product characteristics of brawnand milled rice grits International Journal of Food Properties 2002 5 307

2 Gupta HP Rice bran offers India and oil source J Am Oil Chem Soc 198966 (1) 62

3 Pillaiyar P Rice bran as feed and food The Int J Nutr Dietet 1981 18 1094 Mitsuda H Yasumato K Iwami K Analysis of volatile components in

rice bran Agric Biol Chem 1968 32 4535 Sharma HR Effect of Stabilized Rice Bran and Fenugreek (Trigonella foenum

graecum) Flour on the Physico-Chemical Rheological and BakingCharacteristics of Wheat Flour PhD theses G B Pant University of Agricamp Tech Pant Nagar Pantnagar-263 145 India

6 Luh BS Introduction In Rice Utilization Luh BS Ed AVI PublishingCompany Inc Westport CT 1991 Vol II 1ndash7

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7 Slavin JL Lampe JW Health benefits of rice bran in human nutrition

Cereal Foods World 1992 37 7608 Saunders RM Rice bran composition and potential food uses Food Reviews

International 1986 1 4659 Randall JM Sayre RN Schultz WG Fong RY Mossman AP

Tribelhorn RE Saunders RM Rice bran stabilization by extrusion cooking

for extraction of edible oil Journal of Food Science 1985 50 36110 Desikachar HSR Status Report Preservation of byproducts of rice milling

In Rice Byproducts Preservation Proceedings of Byproducts Utilization

International Conference Valencia Spain Sept 30ndashOct 2 1974 Barber S

Tortosa E Eds Valencia Institute for Agriculture Chemistry and Food

Technology 1977 Vol II 1ndash3211 Martin D Gober JS Selhako G Verma L Wells JH Optimizing rice

bran stabilization by extrusion cooking Lousiana Agraculture 1993 30 1312 AACC Approved Methods of the American Association of Cereal Chemist 8th

Ed The Association St Paul MN 198313 Goering HK Soest PJ Forage fiber analysis (apparatus reagent processing

and some applications) Agriculture Handbook No 379 Agricultural Research

Series United States Department of Agriculture 1970 11214 Sharma RD Hypocholesterolemic activity of some Indian gums Nutrition

Research 1986 4 38115 Carpenter KJ Corrected straight acids Procedure for determination of

available lysine in foods Biochem Journal 1960 77 60416 Haug W Lantzsch HJ Sensitive method for the determination of phytate

in cereal and cereal products J Sci Food Agric 1983 34 142317 Narain M Siripurapu SCB Jha M Dwiviedi VK Physico-thermal

properties of rice bran J Food Sci Technol 1978 15 1818 Sosuliski FW The centrifuge method for the flour water absorption in hard

red spring wheat Cereal Chem 1962 39 34419 Lin MJ Humbert ES Sosuliski FW Certain functional properties of

sunflower meal products J Food Sci 1974 39 36820 Inklaar PA Fortuin J Determining the emulsifing and emulsion stabilizing

capacity of protein meal additives Food Technology 1969 23 10321 Kim CJ Byun SM Cheigh HS Kwon TW Optimization of extrusion

bran stabilization process Journal of Food Science 1987a 52 135522 Kim CJ Byun SM Cheigh HS Kwon TW Compression of solvent

extraction characteristics of rice bran pre-treated by hot air drying steam

cooking and extraction J Am Oil Chem Soc 1987b 64 51423 Camire ME Flint SI Thermal processing effects on dietary fiber

composition and hydration capacity in corn meal oat meal and potato

meals Cereal Chem 1991 68 64524 Van Soest PJ Use of detergents in the analysis of fiberous feeds 2 A rapid

method for the determination of fiber and lignin J Assoc Off Anal Chem

1963 66 93325 Matthee V Appledorff H Effect of cooking on vegetable fiber Journal of

Food Sciences 1978 43 1344

Physico-Chemical Characteristics of Rice Bran 613

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26 Bajorck I Nyman M Asp NG Extrusion cooking and dietary fiber Effectson dietary fiber contents and degradation in the rat intestinal tract CerealChem 1984 57 448

27 Siljestrom M Westerlund E Bjorck I Holm J Asp NG Theander PThe effect of various thermal processes on dietary fiber and starch content ofwhole grain wheat and white flour J Cereal Sci 1986 4 315

28 Aoe S Nakapka M Ido K Tamai Y Ohata F Anano Y Availability ofdietary fiber in extruded wheat bran and apparent digestibility in rates ofcoexisting nutrients Cereal Chem 1989 66 252

29 Theander O Torrie JH Studies on chemical modifications in heat processedstarch and wheat flour StarchStaerke 1987 39 88

30 Babcock D Rice bran as a source of dietary fiber Cereal Foods World 198732 538

31 Cheftel JC Nutritional aspects of extrusion cooking Food Chem 198630 263

32 Chauhan GS Verma NS Bains GS Effect of extrusion process on thenutritional quality of rice legume blend Die Nahrung 1988 32 43

33 Asp NG Bjorck IB Nutritional properties of extruded foods In ExtrusionCooking Mercier C Linko P Harper JM Eds American Association ofCereal Chemists St Paul MN 1989 399ndash434

34 James C Sloan S Functional properties of rice bran in model system Journalof Food Science 1984 49 310

35 Wang WM Klopfestein CF Ponte JG Jr Effects of twin screw extrusionon the physical properties of dietary fiber and other components of wholewheat and wheat bran and on the baking quality of wheat bran Cereal Chem1993 76 707

36 Defloor I De Geest C Schellenkens M Martens A Delour JAEmulsifiers andor extruded starch in the production of bread from cassavaCereal Chem 1991 68 323

37 Loeb JE Mayne RY Effect of moisture on micro flora and formation offree fatty acids in rice bran Cereal Chem 1952 29 163

38 Sayre RN Saunders RM Enochian RV Shultz WG Beagle ECReview of rice bran stabilization systems with emphasis on extrusion cookingCereal Food World 1982 7 317

614 Sharma Chauhan and Agrawal

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as the sum of neutral detergent fiber and gum fiber according to the methoddescribed by worker[14]

Available lysine was determined by Carpenter method[15] which is based on thereaction of fluorodinitrobenzene (FDNB) with the epsilon-NH2 group of lysine inthe proteins and the colorimetric determination of the DNP-lysine obtained bysubsequent acid hydrolysis Method of Haug and Lantzsch[16] was used to estimatethe phytic acid content in rice bran sample In this method sample extract washeated with acidic iron (ferric) solution of a known iron content The decrease in iron(determined colorimetrically with 2ndash2 bipyridine) in supernatant is a measure ofphytic acid content Free fatty acid contents of raw and stabilized rice bran weredetermined by AACC method[12]

Functional Characteristics

Bulk density of raw and stabilized bran were determined by method ofNarain et al[17] Water absorption capacities of raw and stabilized rice bran weremeasured by a modified method reported by Sosuliski[18] Sample of 25 g wasdispersed with 25mL of water in a 50mL centrifuge tube and allowed the mixtureto stand for 15min at 25C then centrifuged the sample at 3200 rpm for 15minThe amount of water retained by the solids was measured Fat absorption of ricebran were estimated by mixing 5 g sample with 50mL corn oil allowing the mixtureto stand for 15min at room temperature and then centrifuging at 3200 rpm for15min The fat retained by the solids was measured[19]

Fortuin method[20] was followed to determine the protein solubility of branWeighed sample (25 g) was dispersed in 100mL distilled water and stirred for 1 h ata controlled temperature of 50C The solution was then centrifuged for 30min at3200 rpm The supernatant was collected in a flask and the nitrogen content wasdetermined by Kjeldahl method[12] Damaged starch in rice bran was determinedaccording the AACC method[12] The method determines the percentage of starchgranules which are susceptible to hydrolysis by amylase Reducing sugars resultingfrom the enzymatic action on damaged starch are measured by ferrycyanide methodand converted to damage starch by using a factor of 0082

RESULT AND DISCUSSION

Proximate compositions and calorific value of dry heat treated and extruded ricebran comparable to raw rice bran are presented in Table 1 From the table it can bereveled that only the crude fat and crude ash contents were affected significantly( plt 005) by the method of stabilization whereas the other constituents and calorificvalue remained almost unchanged after stabilization The extruded rice bran hadsignificantly ( plt 005) higher ash content (862) than did the dry heat treated ricebran (81) A slight increase in ash content after extrusion may be due to thecontamination of extrudates with mineral present in water used in wet extrusionprocessing of bran Crude fat content of extrusion stabilized rice bran wassignificantly ( plt 005) higher than raw rice bran This indicated that stabilization

606 Sharma Chauhan and Agrawal

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Table

1

Effectofmethodofstabilizationontheproxim

ate

compositionandcalorificvalueofrice

bran

Methodsof

stabilization

Crudeprotein

(kg100kgbran)

Crudefat

(kg100kgbran)

Crudefiber

(kg100kgbran)

Crudeash

(kg100kgbran)

Carbohydrates

(kg100kgbran)

Calorificvalue

(KJ100gbran)

RRB

1605

1472

720

840

3972

1486

DHTRB

1590

1506

719

817

3980

1502

ERB

1601

1569

733

862

3995

1504

CD

atP005

NS

0484

NS

022

NS

NS

Data

reported

are

theaverageoftriplicate

determinations

NSNonsignificant

RRBraw

rice

branDHTdry

heattreatedrice

branERBextruded

rice

bran

Physico-Chemical Characteristics of Rice Bran 607

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ORDER REPRINTS

process of rice bran cause fat cells to coalesce into oil droplets and rapture cellstructure thereby improving the speed of oil extraction[2122] However extrusioncooking appeared to be more effective than the dry heat method and theprocess may have great economic benefits for rice growing region in India Theresults of the proximate compositions of rice bran are in agreement with thosereported by worker[68]

Table 2 displays the effects of method of stabilization on sugars fiber availablelysine and phytic acid contents of rice bran The contents of reducing nonreducingand total sugars remained unaffected and did not differ significantly ( pgt 005) fromraw rice bran It has been reported that starch and nonreducing sugars such assucrose might be degraded during extrusion to form reducing sugars[23] But in thepresent investigation it appeared that the extent of heat processing applied on ricebran was not severe enough to cause this change or some reducing sugars might havebeen formed and took part in the browning reaction as observed from the color ofthe stabilized rice bran which were significantly more than the raw rice bran Theneural detergent fiber (NDF) contents of raw and dry heat treated rice bran didnot differ significantly However after extrusion stabilization the NDF wassignificantly increased Similar effects were observed in gum fiber and total fiberEarlier workers[2425] also reported that neutral detergent fiber increased after heatprocessing due to the formation of compounds which were insoluble in detergentsHeat treatment also exhibited a significant effect on the contents of gum fiberExtrusion stabilized rice bran showed highest content of gum fiber followed bydry heat stabilized rice bran Increased gum fiber in extruded rice bran could bethe result of disruption of covalent and noncovalent bonds of the complexmoeties leading to the formation of more water soluble and alcohol precipitablefragments Almost similar results were also reported by various[26ndash28] researchersAs the contents of NDF and gum fiber increased the increase in total fibercalculated as the sum of NDF and gum fiber was also evident[29] Although somedifferences existed in the fiber constituents of rice bran the values observed in thisstudy were in close agreement with those reported by other workers[830] Thestabilization of rice bran had a significant effect ( plt 005) on lysine responseFDNB-reactive lysine contents of dry heat treated rice bran and extruded rice were369 g and 395 g16 g N compared to 409 g16 g N in raw bran indicating a greaterloss of lysine availability by dry heat method Higher temperature short timeextrusion processing when carried out under wet conditions has been reported to befavorable in terms of lysine retention[31] Heat stabilization of rice bran significantly( plt 005) reduced the phytic acid content of rice bran from 293mgg in raw rice to2650mgg in dry heat treated rice bran and 2466mgg in extruded rice branrespectively Earlier work[3233] showed a significant reduction in phytic acid duringextrusion processing of foods

Functional characteristics of rice bran as summarized in Table 3 showed thatthe bulk density of stabilized rice bran increased significantly ( plt 005) Earlierworkers[2122] also reported similar findings and the higher bulk density of extrudedrice bran was observed to increase percolation rate of the solvent through theextrudates and hence better efficiency of oil extraction

Extruded rice bran had the highest water absorption (1709 g100 g) followed bydry-heat treated rice bran (14378 g100 g) these figure are lower than whereas water

608 Sharma Chauhan and Agrawal

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Table

2

Effectofmethodofstabilizationonsugarandfiber

compoundsavailable

lysine

andphyticacidcontents

ofrice

bran

Methodsof

stabilization

Sugars

Fiber

Available

lysine

g16gN

(notclear)

Phytic

acid

(mgg

bran)

Reducing

sugars

(kg100kg

bran)

Nonreducing

sugars

(kg100kg

bran)

Total

sugars

(kg100kg

bran)

NDF

(kg100kg

bran)

Gum

fiber

(kg100kg

bran)

Total

fiber

(kg100kg

bran)

RRB

090

231

311

2363

095

2458

409

2933

DHTRB

089

212

300

2486

153

2625

369

2450

ERB

087

212

301

272

182

2898

395

2466

CD

atP005

NS

NS

NS

138

023

120

024

295

Data

reported

are

theaverageoftriplicate

determinations

NSNonsignificant

RRBraw

rice

branDHTdry

heattreatedrice

branERBextruded

rice

bran

Physico-Chemical Characteristics of Rice Bran 609

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Table

3

Effectofmethodofstabilizationonthefunctionalcharacteristics

ofrice

Methodsof

stabilization

Bulk

density

(gm

L)

Waterabsorption

(g100g)

Watersolubility

(g100g)

Fatabsorption

(g100g)

Protein

solubility

(g100g)

Damaged

starch

(g100g)

Visual

color

RRB

0500

14368

757

9632

732

082

Lighttan

DHTRB

0548

15691

934

8128

444

325

Brown

ERB

0593

17093

933

7260

303

507

Dark

brown

CD

atP005

0026

3696

0608

2756

0635

0300

mdash

Data

reported

are

theaverageoftriplicate

determinations

RRBraw

rice

branDHTdry

heattreatedrice

branERBextruded

rice

bran

610 Sharma Chauhan and Agrawal

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absorptions in the range of 2131ndash1822 of edible stabilized rice bran as reportedearlier[34] The variation may be attributed to the source of bran and their processing

conditions Similar trend was observed for water solubility Increase in watersolubility of stabilized rice bran may be due to the solubilization of the starchcomponent during heat processing of rice bran by dry heat and extrusion

stabilization A significant decrease in fat absorption characteristics of rice branafter heat treatment was observed which may be due to the changes in bed porosity

and pore size of rice branProtein solubility was highest (732 g100 g ) in raw rice bran and lowest (303)

in extruded rice bran indicating the occurrence of protein denaturation during heatstabilization of rice bran as has been reported earlier[3135] also Heat stabilization

of significantly ( p 005) increased the damaged starch (enzyme susceptible starch)content in rice bran as compared to raw rice bran Result of worker[35] also indicatedhigher content of damaged starch in extruded wheat bran than the raw bran The

formation of damaged starch during extrusionheat processing may be important inyeast fermentation and can act as a functional agent in bran dough[36] Color of the

bran as observed visually extruded bran was dark brown in color whereas the dryheat treated bran was just brown and the raw bran was light tan in color Thechanges in color upon heating may be attributed to the formation of Maillard

reaction compounds during extrusion and partly to the solubilization of colorpigments of raw bran

To evaluate the effectiveness of rice bran stabilization methods (dry heat andextrusion processing) a storage study was carried out The changes in free fatty

acid (FFA) contents recorded during storage are presented in Table 4 Stabilizationmethods and storage period significantly ( plt 005) affected the rate of production offree fatty acids A highly significant increase in FFA was observed in raw rice bran

during storage period FFA content in raw rice bran increased from an initial level of405ndash6460 at 60 days of storage This phenomena is typical of raw rice bran and

results in the development of hydrolytic rancidity in unstabilized rice bran[11] Thishas been attributed to the presence of active inherent lipase system of rice bran whichhydrolyses the oil free fatty acids and glycerol and renders bran unfit for oil

Table 4 Effect of the methods of stabilization and storage period on the development

of free fatty acids (FFAs) in rice bran

Methods of

stabilization

Free fatty acids kg100 kg bran

storage period (days)

0 15 30 45 60

RRB 405 1358 2046 3775 6460

DHTRB 366 375 379 570 915

ERB 385 408 422 420 410

CD at P 005 methods of stabilizationfrac14 0399

CD at P 005 storage periodfrac14 0515

CD at P 005 methods storage periodfrac14 0893

RRB raw rice bran DHT dry heat treated rice bran ERB extruded rice bran

Physico-Chemical Characteristics of Rice Bran 611

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extraction and human consumption Dry heat method of stabilization restricted thedevelopment of FFAs up to 30 days of storage and thereafter a significant increasewas observed This increase in FFAs content of bran may be attributed to thepresence of residual lipolytic activity of enzyme lipase which increased underfavorable conditions during storage Bran might have absorbed some moistureduring storage thereby favoring the lipolytic activity This type of behavior withdry-heat treated rice bran was attributed to the incomplete destruction of lipase bydry heat method and increase in moisture content of rice bran during storage[37]

By extrusion stabilization method the free fatty acid content of rice bran did notincrease significantly ( pgt 005) even at 60 days of storage indicating that theextrusion processing of rice bran is more effective in destroying the lipolytic systemof rice bran than the dry heat method The capability of the extruder in inactivat-ing the fat hydrolyzing enzymes of rice bran has also been reported earlier[911]

Less then 5 FFAs are stated to be desirable in economic refining of oil[38]

Sensory analysis[11] revealed that experienced panelists could not distinguish rancidbran from nonrancid bran until the level of free fatty acids exceeded 15However the level of fatty acids in bran that is considered acceptable for humanconsumption is 4 according to US Standards[8]

CONCLUSION

From the present investigation it can be concluded that the functional propertiessuch as water absorption water solubility bulk density and enzyme susceptiblestarch of rice bran improved significantly after stabilization However the increaseswere more pronounced in extrusion stabilized rice bran On the other hand extrusionstabilized rice bran exhibited lower fat absorption and fat solubility than dryheat stabilized rice bran The improvement in shelf life was also much higher forthe rice bran stabilized by using extrusion technology than by dry heat treatment

REFERENCES

1 Gujral HS Singh N Extrusion behavior and product characteristics of brawnand milled rice grits International Journal of Food Properties 2002 5 307

2 Gupta HP Rice bran offers India and oil source J Am Oil Chem Soc 198966 (1) 62

3 Pillaiyar P Rice bran as feed and food The Int J Nutr Dietet 1981 18 1094 Mitsuda H Yasumato K Iwami K Analysis of volatile components in

rice bran Agric Biol Chem 1968 32 4535 Sharma HR Effect of Stabilized Rice Bran and Fenugreek (Trigonella foenum

graecum) Flour on the Physico-Chemical Rheological and BakingCharacteristics of Wheat Flour PhD theses G B Pant University of Agricamp Tech Pant Nagar Pantnagar-263 145 India

6 Luh BS Introduction In Rice Utilization Luh BS Ed AVI PublishingCompany Inc Westport CT 1991 Vol II 1ndash7

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7 Slavin JL Lampe JW Health benefits of rice bran in human nutrition

Cereal Foods World 1992 37 7608 Saunders RM Rice bran composition and potential food uses Food Reviews

International 1986 1 4659 Randall JM Sayre RN Schultz WG Fong RY Mossman AP

Tribelhorn RE Saunders RM Rice bran stabilization by extrusion cooking

for extraction of edible oil Journal of Food Science 1985 50 36110 Desikachar HSR Status Report Preservation of byproducts of rice milling

In Rice Byproducts Preservation Proceedings of Byproducts Utilization

International Conference Valencia Spain Sept 30ndashOct 2 1974 Barber S

Tortosa E Eds Valencia Institute for Agriculture Chemistry and Food

Technology 1977 Vol II 1ndash3211 Martin D Gober JS Selhako G Verma L Wells JH Optimizing rice

bran stabilization by extrusion cooking Lousiana Agraculture 1993 30 1312 AACC Approved Methods of the American Association of Cereal Chemist 8th

Ed The Association St Paul MN 198313 Goering HK Soest PJ Forage fiber analysis (apparatus reagent processing

and some applications) Agriculture Handbook No 379 Agricultural Research

Series United States Department of Agriculture 1970 11214 Sharma RD Hypocholesterolemic activity of some Indian gums Nutrition

Research 1986 4 38115 Carpenter KJ Corrected straight acids Procedure for determination of

available lysine in foods Biochem Journal 1960 77 60416 Haug W Lantzsch HJ Sensitive method for the determination of phytate

in cereal and cereal products J Sci Food Agric 1983 34 142317 Narain M Siripurapu SCB Jha M Dwiviedi VK Physico-thermal

properties of rice bran J Food Sci Technol 1978 15 1818 Sosuliski FW The centrifuge method for the flour water absorption in hard

red spring wheat Cereal Chem 1962 39 34419 Lin MJ Humbert ES Sosuliski FW Certain functional properties of

sunflower meal products J Food Sci 1974 39 36820 Inklaar PA Fortuin J Determining the emulsifing and emulsion stabilizing

capacity of protein meal additives Food Technology 1969 23 10321 Kim CJ Byun SM Cheigh HS Kwon TW Optimization of extrusion

bran stabilization process Journal of Food Science 1987a 52 135522 Kim CJ Byun SM Cheigh HS Kwon TW Compression of solvent

extraction characteristics of rice bran pre-treated by hot air drying steam

cooking and extraction J Am Oil Chem Soc 1987b 64 51423 Camire ME Flint SI Thermal processing effects on dietary fiber

composition and hydration capacity in corn meal oat meal and potato

meals Cereal Chem 1991 68 64524 Van Soest PJ Use of detergents in the analysis of fiberous feeds 2 A rapid

method for the determination of fiber and lignin J Assoc Off Anal Chem

1963 66 93325 Matthee V Appledorff H Effect of cooking on vegetable fiber Journal of

Food Sciences 1978 43 1344

Physico-Chemical Characteristics of Rice Bran 613

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26 Bajorck I Nyman M Asp NG Extrusion cooking and dietary fiber Effectson dietary fiber contents and degradation in the rat intestinal tract CerealChem 1984 57 448

27 Siljestrom M Westerlund E Bjorck I Holm J Asp NG Theander PThe effect of various thermal processes on dietary fiber and starch content ofwhole grain wheat and white flour J Cereal Sci 1986 4 315

28 Aoe S Nakapka M Ido K Tamai Y Ohata F Anano Y Availability ofdietary fiber in extruded wheat bran and apparent digestibility in rates ofcoexisting nutrients Cereal Chem 1989 66 252

29 Theander O Torrie JH Studies on chemical modifications in heat processedstarch and wheat flour StarchStaerke 1987 39 88

30 Babcock D Rice bran as a source of dietary fiber Cereal Foods World 198732 538

31 Cheftel JC Nutritional aspects of extrusion cooking Food Chem 198630 263

32 Chauhan GS Verma NS Bains GS Effect of extrusion process on thenutritional quality of rice legume blend Die Nahrung 1988 32 43

33 Asp NG Bjorck IB Nutritional properties of extruded foods In ExtrusionCooking Mercier C Linko P Harper JM Eds American Association ofCereal Chemists St Paul MN 1989 399ndash434

34 James C Sloan S Functional properties of rice bran in model system Journalof Food Science 1984 49 310

35 Wang WM Klopfestein CF Ponte JG Jr Effects of twin screw extrusionon the physical properties of dietary fiber and other components of wholewheat and wheat bran and on the baking quality of wheat bran Cereal Chem1993 76 707

36 Defloor I De Geest C Schellenkens M Martens A Delour JAEmulsifiers andor extruded starch in the production of bread from cassavaCereal Chem 1991 68 323

37 Loeb JE Mayne RY Effect of moisture on micro flora and formation offree fatty acids in rice bran Cereal Chem 1952 29 163

38 Sayre RN Saunders RM Enochian RV Shultz WG Beagle ECReview of rice bran stabilization systems with emphasis on extrusion cookingCereal Food World 1982 7 317

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Table

1

Effectofmethodofstabilizationontheproxim

ate

compositionandcalorificvalueofrice

bran

Methodsof

stabilization

Crudeprotein

(kg100kgbran)

Crudefat

(kg100kgbran)

Crudefiber

(kg100kgbran)

Crudeash

(kg100kgbran)

Carbohydrates

(kg100kgbran)

Calorificvalue

(KJ100gbran)

RRB

1605

1472

720

840

3972

1486

DHTRB

1590

1506

719

817

3980

1502

ERB

1601

1569

733

862

3995

1504

CD

atP005

NS

0484

NS

022

NS

NS

Data

reported

are

theaverageoftriplicate

determinations

NSNonsignificant

RRBraw

rice

branDHTdry

heattreatedrice

branERBextruded

rice

bran

Physico-Chemical Characteristics of Rice Bran 607

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ORDER REPRINTS

process of rice bran cause fat cells to coalesce into oil droplets and rapture cellstructure thereby improving the speed of oil extraction[2122] However extrusioncooking appeared to be more effective than the dry heat method and theprocess may have great economic benefits for rice growing region in India Theresults of the proximate compositions of rice bran are in agreement with thosereported by worker[68]

Table 2 displays the effects of method of stabilization on sugars fiber availablelysine and phytic acid contents of rice bran The contents of reducing nonreducingand total sugars remained unaffected and did not differ significantly ( pgt 005) fromraw rice bran It has been reported that starch and nonreducing sugars such assucrose might be degraded during extrusion to form reducing sugars[23] But in thepresent investigation it appeared that the extent of heat processing applied on ricebran was not severe enough to cause this change or some reducing sugars might havebeen formed and took part in the browning reaction as observed from the color ofthe stabilized rice bran which were significantly more than the raw rice bran Theneural detergent fiber (NDF) contents of raw and dry heat treated rice bran didnot differ significantly However after extrusion stabilization the NDF wassignificantly increased Similar effects were observed in gum fiber and total fiberEarlier workers[2425] also reported that neutral detergent fiber increased after heatprocessing due to the formation of compounds which were insoluble in detergentsHeat treatment also exhibited a significant effect on the contents of gum fiberExtrusion stabilized rice bran showed highest content of gum fiber followed bydry heat stabilized rice bran Increased gum fiber in extruded rice bran could bethe result of disruption of covalent and noncovalent bonds of the complexmoeties leading to the formation of more water soluble and alcohol precipitablefragments Almost similar results were also reported by various[26ndash28] researchersAs the contents of NDF and gum fiber increased the increase in total fibercalculated as the sum of NDF and gum fiber was also evident[29] Although somedifferences existed in the fiber constituents of rice bran the values observed in thisstudy were in close agreement with those reported by other workers[830] Thestabilization of rice bran had a significant effect ( plt 005) on lysine responseFDNB-reactive lysine contents of dry heat treated rice bran and extruded rice were369 g and 395 g16 g N compared to 409 g16 g N in raw bran indicating a greaterloss of lysine availability by dry heat method Higher temperature short timeextrusion processing when carried out under wet conditions has been reported to befavorable in terms of lysine retention[31] Heat stabilization of rice bran significantly( plt 005) reduced the phytic acid content of rice bran from 293mgg in raw rice to2650mgg in dry heat treated rice bran and 2466mgg in extruded rice branrespectively Earlier work[3233] showed a significant reduction in phytic acid duringextrusion processing of foods

Functional characteristics of rice bran as summarized in Table 3 showed thatthe bulk density of stabilized rice bran increased significantly ( plt 005) Earlierworkers[2122] also reported similar findings and the higher bulk density of extrudedrice bran was observed to increase percolation rate of the solvent through theextrudates and hence better efficiency of oil extraction

Extruded rice bran had the highest water absorption (1709 g100 g) followed bydry-heat treated rice bran (14378 g100 g) these figure are lower than whereas water

608 Sharma Chauhan and Agrawal

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Table

2

Effectofmethodofstabilizationonsugarandfiber

compoundsavailable

lysine

andphyticacidcontents

ofrice

bran

Methodsof

stabilization

Sugars

Fiber

Available

lysine

g16gN

(notclear)

Phytic

acid

(mgg

bran)

Reducing

sugars

(kg100kg

bran)

Nonreducing

sugars

(kg100kg

bran)

Total

sugars

(kg100kg

bran)

NDF

(kg100kg

bran)

Gum

fiber

(kg100kg

bran)

Total

fiber

(kg100kg

bran)

RRB

090

231

311

2363

095

2458

409

2933

DHTRB

089

212

300

2486

153

2625

369

2450

ERB

087

212

301

272

182

2898

395

2466

CD

atP005

NS

NS

NS

138

023

120

024

295

Data

reported

are

theaverageoftriplicate

determinations

NSNonsignificant

RRBraw

rice

branDHTdry

heattreatedrice

branERBextruded

rice

bran

Physico-Chemical Characteristics of Rice Bran 609

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Table

3

Effectofmethodofstabilizationonthefunctionalcharacteristics

ofrice

Methodsof

stabilization

Bulk

density

(gm

L)

Waterabsorption

(g100g)

Watersolubility

(g100g)

Fatabsorption

(g100g)

Protein

solubility

(g100g)

Damaged

starch

(g100g)

Visual

color

RRB

0500

14368

757

9632

732

082

Lighttan

DHTRB

0548

15691

934

8128

444

325

Brown

ERB

0593

17093

933

7260

303

507

Dark

brown

CD

atP005

0026

3696

0608

2756

0635

0300

mdash

Data

reported

are

theaverageoftriplicate

determinations

RRBraw

rice

branDHTdry

heattreatedrice

branERBextruded

rice

bran

610 Sharma Chauhan and Agrawal

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absorptions in the range of 2131ndash1822 of edible stabilized rice bran as reportedearlier[34] The variation may be attributed to the source of bran and their processing

conditions Similar trend was observed for water solubility Increase in watersolubility of stabilized rice bran may be due to the solubilization of the starchcomponent during heat processing of rice bran by dry heat and extrusion

stabilization A significant decrease in fat absorption characteristics of rice branafter heat treatment was observed which may be due to the changes in bed porosity

and pore size of rice branProtein solubility was highest (732 g100 g ) in raw rice bran and lowest (303)

in extruded rice bran indicating the occurrence of protein denaturation during heatstabilization of rice bran as has been reported earlier[3135] also Heat stabilization

of significantly ( p 005) increased the damaged starch (enzyme susceptible starch)content in rice bran as compared to raw rice bran Result of worker[35] also indicatedhigher content of damaged starch in extruded wheat bran than the raw bran The

formation of damaged starch during extrusionheat processing may be important inyeast fermentation and can act as a functional agent in bran dough[36] Color of the

bran as observed visually extruded bran was dark brown in color whereas the dryheat treated bran was just brown and the raw bran was light tan in color Thechanges in color upon heating may be attributed to the formation of Maillard

reaction compounds during extrusion and partly to the solubilization of colorpigments of raw bran

To evaluate the effectiveness of rice bran stabilization methods (dry heat andextrusion processing) a storage study was carried out The changes in free fatty

acid (FFA) contents recorded during storage are presented in Table 4 Stabilizationmethods and storage period significantly ( plt 005) affected the rate of production offree fatty acids A highly significant increase in FFA was observed in raw rice bran

during storage period FFA content in raw rice bran increased from an initial level of405ndash6460 at 60 days of storage This phenomena is typical of raw rice bran and

results in the development of hydrolytic rancidity in unstabilized rice bran[11] Thishas been attributed to the presence of active inherent lipase system of rice bran whichhydrolyses the oil free fatty acids and glycerol and renders bran unfit for oil

Table 4 Effect of the methods of stabilization and storage period on the development

of free fatty acids (FFAs) in rice bran

Methods of

stabilization

Free fatty acids kg100 kg bran

storage period (days)

0 15 30 45 60

RRB 405 1358 2046 3775 6460

DHTRB 366 375 379 570 915

ERB 385 408 422 420 410

CD at P 005 methods of stabilizationfrac14 0399

CD at P 005 storage periodfrac14 0515

CD at P 005 methods storage periodfrac14 0893

RRB raw rice bran DHT dry heat treated rice bran ERB extruded rice bran

Physico-Chemical Characteristics of Rice Bran 611

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extraction and human consumption Dry heat method of stabilization restricted thedevelopment of FFAs up to 30 days of storage and thereafter a significant increasewas observed This increase in FFAs content of bran may be attributed to thepresence of residual lipolytic activity of enzyme lipase which increased underfavorable conditions during storage Bran might have absorbed some moistureduring storage thereby favoring the lipolytic activity This type of behavior withdry-heat treated rice bran was attributed to the incomplete destruction of lipase bydry heat method and increase in moisture content of rice bran during storage[37]

By extrusion stabilization method the free fatty acid content of rice bran did notincrease significantly ( pgt 005) even at 60 days of storage indicating that theextrusion processing of rice bran is more effective in destroying the lipolytic systemof rice bran than the dry heat method The capability of the extruder in inactivat-ing the fat hydrolyzing enzymes of rice bran has also been reported earlier[911]

Less then 5 FFAs are stated to be desirable in economic refining of oil[38]

Sensory analysis[11] revealed that experienced panelists could not distinguish rancidbran from nonrancid bran until the level of free fatty acids exceeded 15However the level of fatty acids in bran that is considered acceptable for humanconsumption is 4 according to US Standards[8]

CONCLUSION

From the present investigation it can be concluded that the functional propertiessuch as water absorption water solubility bulk density and enzyme susceptiblestarch of rice bran improved significantly after stabilization However the increaseswere more pronounced in extrusion stabilized rice bran On the other hand extrusionstabilized rice bran exhibited lower fat absorption and fat solubility than dryheat stabilized rice bran The improvement in shelf life was also much higher forthe rice bran stabilized by using extrusion technology than by dry heat treatment

REFERENCES

1 Gujral HS Singh N Extrusion behavior and product characteristics of brawnand milled rice grits International Journal of Food Properties 2002 5 307

2 Gupta HP Rice bran offers India and oil source J Am Oil Chem Soc 198966 (1) 62

3 Pillaiyar P Rice bran as feed and food The Int J Nutr Dietet 1981 18 1094 Mitsuda H Yasumato K Iwami K Analysis of volatile components in

rice bran Agric Biol Chem 1968 32 4535 Sharma HR Effect of Stabilized Rice Bran and Fenugreek (Trigonella foenum

graecum) Flour on the Physico-Chemical Rheological and BakingCharacteristics of Wheat Flour PhD theses G B Pant University of Agricamp Tech Pant Nagar Pantnagar-263 145 India

6 Luh BS Introduction In Rice Utilization Luh BS Ed AVI PublishingCompany Inc Westport CT 1991 Vol II 1ndash7

612 Sharma Chauhan and Agrawal

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ded

by [

Nor

thea

ster

n U

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rsity

] at

14

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er 2

014

ORDER REPRINTS

7 Slavin JL Lampe JW Health benefits of rice bran in human nutrition

Cereal Foods World 1992 37 7608 Saunders RM Rice bran composition and potential food uses Food Reviews

International 1986 1 4659 Randall JM Sayre RN Schultz WG Fong RY Mossman AP

Tribelhorn RE Saunders RM Rice bran stabilization by extrusion cooking

for extraction of edible oil Journal of Food Science 1985 50 36110 Desikachar HSR Status Report Preservation of byproducts of rice milling

In Rice Byproducts Preservation Proceedings of Byproducts Utilization

International Conference Valencia Spain Sept 30ndashOct 2 1974 Barber S

Tortosa E Eds Valencia Institute for Agriculture Chemistry and Food

Technology 1977 Vol II 1ndash3211 Martin D Gober JS Selhako G Verma L Wells JH Optimizing rice

bran stabilization by extrusion cooking Lousiana Agraculture 1993 30 1312 AACC Approved Methods of the American Association of Cereal Chemist 8th

Ed The Association St Paul MN 198313 Goering HK Soest PJ Forage fiber analysis (apparatus reagent processing

and some applications) Agriculture Handbook No 379 Agricultural Research

Series United States Department of Agriculture 1970 11214 Sharma RD Hypocholesterolemic activity of some Indian gums Nutrition

Research 1986 4 38115 Carpenter KJ Corrected straight acids Procedure for determination of

available lysine in foods Biochem Journal 1960 77 60416 Haug W Lantzsch HJ Sensitive method for the determination of phytate

in cereal and cereal products J Sci Food Agric 1983 34 142317 Narain M Siripurapu SCB Jha M Dwiviedi VK Physico-thermal

properties of rice bran J Food Sci Technol 1978 15 1818 Sosuliski FW The centrifuge method for the flour water absorption in hard

red spring wheat Cereal Chem 1962 39 34419 Lin MJ Humbert ES Sosuliski FW Certain functional properties of

sunflower meal products J Food Sci 1974 39 36820 Inklaar PA Fortuin J Determining the emulsifing and emulsion stabilizing

capacity of protein meal additives Food Technology 1969 23 10321 Kim CJ Byun SM Cheigh HS Kwon TW Optimization of extrusion

bran stabilization process Journal of Food Science 1987a 52 135522 Kim CJ Byun SM Cheigh HS Kwon TW Compression of solvent

extraction characteristics of rice bran pre-treated by hot air drying steam

cooking and extraction J Am Oil Chem Soc 1987b 64 51423 Camire ME Flint SI Thermal processing effects on dietary fiber

composition and hydration capacity in corn meal oat meal and potato

meals Cereal Chem 1991 68 64524 Van Soest PJ Use of detergents in the analysis of fiberous feeds 2 A rapid

method for the determination of fiber and lignin J Assoc Off Anal Chem

1963 66 93325 Matthee V Appledorff H Effect of cooking on vegetable fiber Journal of

Food Sciences 1978 43 1344

Physico-Chemical Characteristics of Rice Bran 613

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26 Bajorck I Nyman M Asp NG Extrusion cooking and dietary fiber Effectson dietary fiber contents and degradation in the rat intestinal tract CerealChem 1984 57 448

27 Siljestrom M Westerlund E Bjorck I Holm J Asp NG Theander PThe effect of various thermal processes on dietary fiber and starch content ofwhole grain wheat and white flour J Cereal Sci 1986 4 315

28 Aoe S Nakapka M Ido K Tamai Y Ohata F Anano Y Availability ofdietary fiber in extruded wheat bran and apparent digestibility in rates ofcoexisting nutrients Cereal Chem 1989 66 252

29 Theander O Torrie JH Studies on chemical modifications in heat processedstarch and wheat flour StarchStaerke 1987 39 88

30 Babcock D Rice bran as a source of dietary fiber Cereal Foods World 198732 538

31 Cheftel JC Nutritional aspects of extrusion cooking Food Chem 198630 263

32 Chauhan GS Verma NS Bains GS Effect of extrusion process on thenutritional quality of rice legume blend Die Nahrung 1988 32 43

33 Asp NG Bjorck IB Nutritional properties of extruded foods In ExtrusionCooking Mercier C Linko P Harper JM Eds American Association ofCereal Chemists St Paul MN 1989 399ndash434

34 James C Sloan S Functional properties of rice bran in model system Journalof Food Science 1984 49 310

35 Wang WM Klopfestein CF Ponte JG Jr Effects of twin screw extrusionon the physical properties of dietary fiber and other components of wholewheat and wheat bran and on the baking quality of wheat bran Cereal Chem1993 76 707

36 Defloor I De Geest C Schellenkens M Martens A Delour JAEmulsifiers andor extruded starch in the production of bread from cassavaCereal Chem 1991 68 323

37 Loeb JE Mayne RY Effect of moisture on micro flora and formation offree fatty acids in rice bran Cereal Chem 1952 29 163

38 Sayre RN Saunders RM Enochian RV Shultz WG Beagle ECReview of rice bran stabilization systems with emphasis on extrusion cookingCereal Food World 1982 7 317

614 Sharma Chauhan and Agrawal

Dow

nloa

ded

by [

Nor

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n U

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rsity

] at

14

55 1

1 O

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er 2

014

Request PermissionOrder Reprints

Reprints of this article can also be ordered at

httpwwwdekkercomservletproductDOI101081JFP200033047

Request Permission or Order Reprints Instantly

Interested in copying and sharing this article In most cases US Copyright Law requires that you get permission from the articlersquos rightsholder before using copyrighted content

All information and materials found in this article including but not limited to text trademarks patents logos graphics and images (the Materials) are the copyrighted works and other forms of intellectual property of Marcel Dekker Inc or its licensors All rights not expressly granted are reserved

Get permission to lawfully reproduce and distribute the Materials or order reprints quickly and painlessly Simply click on the Request Permission Order Reprints link below and follow the instructions Visit the US Copyright Office for information on Fair Use limitations of US copyright law Please refer to The Association of American Publishersrsquo (AAP) website for guidelines on Fair Use in the Classroom

The Materials are for your personal use only and cannot be reformatted reposted resold or distributed by electronic means or otherwise without permission from Marcel Dekker Inc Marcel Dekker Inc grants you the limited right to display the Materials only on your personal computer or personal wireless device and to copy and download single copies of such Materials provided that any copyright trademark or other notice appearing on such Materials is also retained by displayed copied or downloaded as part of the Materials and is not removed or obscured and provided you do not edit modify alter or enhance the Materials Please refer to our Website User Agreement for more details

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ORDER REPRINTS

process of rice bran cause fat cells to coalesce into oil droplets and rapture cellstructure thereby improving the speed of oil extraction[2122] However extrusioncooking appeared to be more effective than the dry heat method and theprocess may have great economic benefits for rice growing region in India Theresults of the proximate compositions of rice bran are in agreement with thosereported by worker[68]

Table 2 displays the effects of method of stabilization on sugars fiber availablelysine and phytic acid contents of rice bran The contents of reducing nonreducingand total sugars remained unaffected and did not differ significantly ( pgt 005) fromraw rice bran It has been reported that starch and nonreducing sugars such assucrose might be degraded during extrusion to form reducing sugars[23] But in thepresent investigation it appeared that the extent of heat processing applied on ricebran was not severe enough to cause this change or some reducing sugars might havebeen formed and took part in the browning reaction as observed from the color ofthe stabilized rice bran which were significantly more than the raw rice bran Theneural detergent fiber (NDF) contents of raw and dry heat treated rice bran didnot differ significantly However after extrusion stabilization the NDF wassignificantly increased Similar effects were observed in gum fiber and total fiberEarlier workers[2425] also reported that neutral detergent fiber increased after heatprocessing due to the formation of compounds which were insoluble in detergentsHeat treatment also exhibited a significant effect on the contents of gum fiberExtrusion stabilized rice bran showed highest content of gum fiber followed bydry heat stabilized rice bran Increased gum fiber in extruded rice bran could bethe result of disruption of covalent and noncovalent bonds of the complexmoeties leading to the formation of more water soluble and alcohol precipitablefragments Almost similar results were also reported by various[26ndash28] researchersAs the contents of NDF and gum fiber increased the increase in total fibercalculated as the sum of NDF and gum fiber was also evident[29] Although somedifferences existed in the fiber constituents of rice bran the values observed in thisstudy were in close agreement with those reported by other workers[830] Thestabilization of rice bran had a significant effect ( plt 005) on lysine responseFDNB-reactive lysine contents of dry heat treated rice bran and extruded rice were369 g and 395 g16 g N compared to 409 g16 g N in raw bran indicating a greaterloss of lysine availability by dry heat method Higher temperature short timeextrusion processing when carried out under wet conditions has been reported to befavorable in terms of lysine retention[31] Heat stabilization of rice bran significantly( plt 005) reduced the phytic acid content of rice bran from 293mgg in raw rice to2650mgg in dry heat treated rice bran and 2466mgg in extruded rice branrespectively Earlier work[3233] showed a significant reduction in phytic acid duringextrusion processing of foods

Functional characteristics of rice bran as summarized in Table 3 showed thatthe bulk density of stabilized rice bran increased significantly ( plt 005) Earlierworkers[2122] also reported similar findings and the higher bulk density of extrudedrice bran was observed to increase percolation rate of the solvent through theextrudates and hence better efficiency of oil extraction

Extruded rice bran had the highest water absorption (1709 g100 g) followed bydry-heat treated rice bran (14378 g100 g) these figure are lower than whereas water

608 Sharma Chauhan and Agrawal

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ORDER REPRINTS

Table

2

Effectofmethodofstabilizationonsugarandfiber

compoundsavailable

lysine

andphyticacidcontents

ofrice

bran

Methodsof

stabilization

Sugars

Fiber

Available

lysine

g16gN

(notclear)

Phytic

acid

(mgg

bran)

Reducing

sugars

(kg100kg

bran)

Nonreducing

sugars

(kg100kg

bran)

Total

sugars

(kg100kg

bran)

NDF

(kg100kg

bran)

Gum

fiber

(kg100kg

bran)

Total

fiber

(kg100kg

bran)

RRB

090

231

311

2363

095

2458

409

2933

DHTRB

089

212

300

2486

153

2625

369

2450

ERB

087

212

301

272

182

2898

395

2466

CD

atP005

NS

NS

NS

138

023

120

024

295

Data

reported

are

theaverageoftriplicate

determinations

NSNonsignificant

RRBraw

rice

branDHTdry

heattreatedrice

branERBextruded

rice

bran

Physico-Chemical Characteristics of Rice Bran 609

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ORDER REPRINTS

Table

3

Effectofmethodofstabilizationonthefunctionalcharacteristics

ofrice

Methodsof

stabilization

Bulk

density

(gm

L)

Waterabsorption

(g100g)

Watersolubility

(g100g)

Fatabsorption

(g100g)

Protein

solubility

(g100g)

Damaged

starch

(g100g)

Visual

color

RRB

0500

14368

757

9632

732

082

Lighttan

DHTRB

0548

15691

934

8128

444

325

Brown

ERB

0593

17093

933

7260

303

507

Dark

brown

CD

atP005

0026

3696

0608

2756

0635

0300

mdash

Data

reported

are

theaverageoftriplicate

determinations

RRBraw

rice

branDHTdry

heattreatedrice

branERBextruded

rice

bran

610 Sharma Chauhan and Agrawal

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ORDER REPRINTS

absorptions in the range of 2131ndash1822 of edible stabilized rice bran as reportedearlier[34] The variation may be attributed to the source of bran and their processing

conditions Similar trend was observed for water solubility Increase in watersolubility of stabilized rice bran may be due to the solubilization of the starchcomponent during heat processing of rice bran by dry heat and extrusion

stabilization A significant decrease in fat absorption characteristics of rice branafter heat treatment was observed which may be due to the changes in bed porosity

and pore size of rice branProtein solubility was highest (732 g100 g ) in raw rice bran and lowest (303)

in extruded rice bran indicating the occurrence of protein denaturation during heatstabilization of rice bran as has been reported earlier[3135] also Heat stabilization

of significantly ( p 005) increased the damaged starch (enzyme susceptible starch)content in rice bran as compared to raw rice bran Result of worker[35] also indicatedhigher content of damaged starch in extruded wheat bran than the raw bran The

formation of damaged starch during extrusionheat processing may be important inyeast fermentation and can act as a functional agent in bran dough[36] Color of the

bran as observed visually extruded bran was dark brown in color whereas the dryheat treated bran was just brown and the raw bran was light tan in color Thechanges in color upon heating may be attributed to the formation of Maillard

reaction compounds during extrusion and partly to the solubilization of colorpigments of raw bran

To evaluate the effectiveness of rice bran stabilization methods (dry heat andextrusion processing) a storage study was carried out The changes in free fatty

acid (FFA) contents recorded during storage are presented in Table 4 Stabilizationmethods and storage period significantly ( plt 005) affected the rate of production offree fatty acids A highly significant increase in FFA was observed in raw rice bran

during storage period FFA content in raw rice bran increased from an initial level of405ndash6460 at 60 days of storage This phenomena is typical of raw rice bran and

results in the development of hydrolytic rancidity in unstabilized rice bran[11] Thishas been attributed to the presence of active inherent lipase system of rice bran whichhydrolyses the oil free fatty acids and glycerol and renders bran unfit for oil

Table 4 Effect of the methods of stabilization and storage period on the development

of free fatty acids (FFAs) in rice bran

Methods of

stabilization

Free fatty acids kg100 kg bran

storage period (days)

0 15 30 45 60

RRB 405 1358 2046 3775 6460

DHTRB 366 375 379 570 915

ERB 385 408 422 420 410

CD at P 005 methods of stabilizationfrac14 0399

CD at P 005 storage periodfrac14 0515

CD at P 005 methods storage periodfrac14 0893

RRB raw rice bran DHT dry heat treated rice bran ERB extruded rice bran

Physico-Chemical Characteristics of Rice Bran 611

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extraction and human consumption Dry heat method of stabilization restricted thedevelopment of FFAs up to 30 days of storage and thereafter a significant increasewas observed This increase in FFAs content of bran may be attributed to thepresence of residual lipolytic activity of enzyme lipase which increased underfavorable conditions during storage Bran might have absorbed some moistureduring storage thereby favoring the lipolytic activity This type of behavior withdry-heat treated rice bran was attributed to the incomplete destruction of lipase bydry heat method and increase in moisture content of rice bran during storage[37]

By extrusion stabilization method the free fatty acid content of rice bran did notincrease significantly ( pgt 005) even at 60 days of storage indicating that theextrusion processing of rice bran is more effective in destroying the lipolytic systemof rice bran than the dry heat method The capability of the extruder in inactivat-ing the fat hydrolyzing enzymes of rice bran has also been reported earlier[911]

Less then 5 FFAs are stated to be desirable in economic refining of oil[38]

Sensory analysis[11] revealed that experienced panelists could not distinguish rancidbran from nonrancid bran until the level of free fatty acids exceeded 15However the level of fatty acids in bran that is considered acceptable for humanconsumption is 4 according to US Standards[8]

CONCLUSION

From the present investigation it can be concluded that the functional propertiessuch as water absorption water solubility bulk density and enzyme susceptiblestarch of rice bran improved significantly after stabilization However the increaseswere more pronounced in extrusion stabilized rice bran On the other hand extrusionstabilized rice bran exhibited lower fat absorption and fat solubility than dryheat stabilized rice bran The improvement in shelf life was also much higher forthe rice bran stabilized by using extrusion technology than by dry heat treatment

REFERENCES

1 Gujral HS Singh N Extrusion behavior and product characteristics of brawnand milled rice grits International Journal of Food Properties 2002 5 307

2 Gupta HP Rice bran offers India and oil source J Am Oil Chem Soc 198966 (1) 62

3 Pillaiyar P Rice bran as feed and food The Int J Nutr Dietet 1981 18 1094 Mitsuda H Yasumato K Iwami K Analysis of volatile components in

rice bran Agric Biol Chem 1968 32 4535 Sharma HR Effect of Stabilized Rice Bran and Fenugreek (Trigonella foenum

graecum) Flour on the Physico-Chemical Rheological and BakingCharacteristics of Wheat Flour PhD theses G B Pant University of Agricamp Tech Pant Nagar Pantnagar-263 145 India

6 Luh BS Introduction In Rice Utilization Luh BS Ed AVI PublishingCompany Inc Westport CT 1991 Vol II 1ndash7

612 Sharma Chauhan and Agrawal

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

ORDER REPRINTS

7 Slavin JL Lampe JW Health benefits of rice bran in human nutrition

Cereal Foods World 1992 37 7608 Saunders RM Rice bran composition and potential food uses Food Reviews

International 1986 1 4659 Randall JM Sayre RN Schultz WG Fong RY Mossman AP

Tribelhorn RE Saunders RM Rice bran stabilization by extrusion cooking

for extraction of edible oil Journal of Food Science 1985 50 36110 Desikachar HSR Status Report Preservation of byproducts of rice milling

In Rice Byproducts Preservation Proceedings of Byproducts Utilization

International Conference Valencia Spain Sept 30ndashOct 2 1974 Barber S

Tortosa E Eds Valencia Institute for Agriculture Chemistry and Food

Technology 1977 Vol II 1ndash3211 Martin D Gober JS Selhako G Verma L Wells JH Optimizing rice

bran stabilization by extrusion cooking Lousiana Agraculture 1993 30 1312 AACC Approved Methods of the American Association of Cereal Chemist 8th

Ed The Association St Paul MN 198313 Goering HK Soest PJ Forage fiber analysis (apparatus reagent processing

and some applications) Agriculture Handbook No 379 Agricultural Research

Series United States Department of Agriculture 1970 11214 Sharma RD Hypocholesterolemic activity of some Indian gums Nutrition

Research 1986 4 38115 Carpenter KJ Corrected straight acids Procedure for determination of

available lysine in foods Biochem Journal 1960 77 60416 Haug W Lantzsch HJ Sensitive method for the determination of phytate

in cereal and cereal products J Sci Food Agric 1983 34 142317 Narain M Siripurapu SCB Jha M Dwiviedi VK Physico-thermal

properties of rice bran J Food Sci Technol 1978 15 1818 Sosuliski FW The centrifuge method for the flour water absorption in hard

red spring wheat Cereal Chem 1962 39 34419 Lin MJ Humbert ES Sosuliski FW Certain functional properties of

sunflower meal products J Food Sci 1974 39 36820 Inklaar PA Fortuin J Determining the emulsifing and emulsion stabilizing

capacity of protein meal additives Food Technology 1969 23 10321 Kim CJ Byun SM Cheigh HS Kwon TW Optimization of extrusion

bran stabilization process Journal of Food Science 1987a 52 135522 Kim CJ Byun SM Cheigh HS Kwon TW Compression of solvent

extraction characteristics of rice bran pre-treated by hot air drying steam

cooking and extraction J Am Oil Chem Soc 1987b 64 51423 Camire ME Flint SI Thermal processing effects on dietary fiber

composition and hydration capacity in corn meal oat meal and potato

meals Cereal Chem 1991 68 64524 Van Soest PJ Use of detergents in the analysis of fiberous feeds 2 A rapid

method for the determination of fiber and lignin J Assoc Off Anal Chem

1963 66 93325 Matthee V Appledorff H Effect of cooking on vegetable fiber Journal of

Food Sciences 1978 43 1344

Physico-Chemical Characteristics of Rice Bran 613

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ORDER REPRINTS

26 Bajorck I Nyman M Asp NG Extrusion cooking and dietary fiber Effectson dietary fiber contents and degradation in the rat intestinal tract CerealChem 1984 57 448

27 Siljestrom M Westerlund E Bjorck I Holm J Asp NG Theander PThe effect of various thermal processes on dietary fiber and starch content ofwhole grain wheat and white flour J Cereal Sci 1986 4 315

28 Aoe S Nakapka M Ido K Tamai Y Ohata F Anano Y Availability ofdietary fiber in extruded wheat bran and apparent digestibility in rates ofcoexisting nutrients Cereal Chem 1989 66 252

29 Theander O Torrie JH Studies on chemical modifications in heat processedstarch and wheat flour StarchStaerke 1987 39 88

30 Babcock D Rice bran as a source of dietary fiber Cereal Foods World 198732 538

31 Cheftel JC Nutritional aspects of extrusion cooking Food Chem 198630 263

32 Chauhan GS Verma NS Bains GS Effect of extrusion process on thenutritional quality of rice legume blend Die Nahrung 1988 32 43

33 Asp NG Bjorck IB Nutritional properties of extruded foods In ExtrusionCooking Mercier C Linko P Harper JM Eds American Association ofCereal Chemists St Paul MN 1989 399ndash434

34 James C Sloan S Functional properties of rice bran in model system Journalof Food Science 1984 49 310

35 Wang WM Klopfestein CF Ponte JG Jr Effects of twin screw extrusionon the physical properties of dietary fiber and other components of wholewheat and wheat bran and on the baking quality of wheat bran Cereal Chem1993 76 707

36 Defloor I De Geest C Schellenkens M Martens A Delour JAEmulsifiers andor extruded starch in the production of bread from cassavaCereal Chem 1991 68 323

37 Loeb JE Mayne RY Effect of moisture on micro flora and formation offree fatty acids in rice bran Cereal Chem 1952 29 163

38 Sayre RN Saunders RM Enochian RV Shultz WG Beagle ECReview of rice bran stabilization systems with emphasis on extrusion cookingCereal Food World 1982 7 317

614 Sharma Chauhan and Agrawal

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

Request PermissionOrder Reprints

Reprints of this article can also be ordered at

httpwwwdekkercomservletproductDOI101081JFP200033047

Request Permission or Order Reprints Instantly

Interested in copying and sharing this article In most cases US Copyright Law requires that you get permission from the articlersquos rightsholder before using copyrighted content

All information and materials found in this article including but not limited to text trademarks patents logos graphics and images (the Materials) are the copyrighted works and other forms of intellectual property of Marcel Dekker Inc or its licensors All rights not expressly granted are reserved

Get permission to lawfully reproduce and distribute the Materials or order reprints quickly and painlessly Simply click on the Request Permission Order Reprints link below and follow the instructions Visit the US Copyright Office for information on Fair Use limitations of US copyright law Please refer to The Association of American Publishersrsquo (AAP) website for guidelines on Fair Use in the Classroom

The Materials are for your personal use only and cannot be reformatted reposted resold or distributed by electronic means or otherwise without permission from Marcel Dekker Inc Marcel Dekker Inc grants you the limited right to display the Materials only on your personal computer or personal wireless device and to copy and download single copies of such Materials provided that any copyright trademark or other notice appearing on such Materials is also retained by displayed copied or downloaded as part of the Materials and is not removed or obscured and provided you do not edit modify alter or enhance the Materials Please refer to our Website User Agreement for more details

Dow

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ded

by [

Nor

thea

ster

n U

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rsity

] at

14

55 1

1 O

ctob

er 2

014

ORDER REPRINTS

Table

2

Effectofmethodofstabilizationonsugarandfiber

compoundsavailable

lysine

andphyticacidcontents

ofrice

bran

Methodsof

stabilization

Sugars

Fiber

Available

lysine

g16gN

(notclear)

Phytic

acid

(mgg

bran)

Reducing

sugars

(kg100kg

bran)

Nonreducing

sugars

(kg100kg

bran)

Total

sugars

(kg100kg

bran)

NDF

(kg100kg

bran)

Gum

fiber

(kg100kg

bran)

Total

fiber

(kg100kg

bran)

RRB

090

231

311

2363

095

2458

409

2933

DHTRB

089

212

300

2486

153

2625

369

2450

ERB

087

212

301

272

182

2898

395

2466

CD

atP005

NS

NS

NS

138

023

120

024

295

Data

reported

are

theaverageoftriplicate

determinations

NSNonsignificant

RRBraw

rice

branDHTdry

heattreatedrice

branERBextruded

rice

bran

Physico-Chemical Characteristics of Rice Bran 609

Dow

nloa

ded

by [

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thea

ster

n U

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rsity

] at

14

55 1

1 O

ctob

er 2

014

ORDER REPRINTS

Table

3

Effectofmethodofstabilizationonthefunctionalcharacteristics

ofrice

Methodsof

stabilization

Bulk

density

(gm

L)

Waterabsorption

(g100g)

Watersolubility

(g100g)

Fatabsorption

(g100g)

Protein

solubility

(g100g)

Damaged

starch

(g100g)

Visual

color

RRB

0500

14368

757

9632

732

082

Lighttan

DHTRB

0548

15691

934

8128

444

325

Brown

ERB

0593

17093

933

7260

303

507

Dark

brown

CD

atP005

0026

3696

0608

2756

0635

0300

mdash

Data

reported

are

theaverageoftriplicate

determinations

RRBraw

rice

branDHTdry

heattreatedrice

branERBextruded

rice

bran

610 Sharma Chauhan and Agrawal

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

ORDER REPRINTS

absorptions in the range of 2131ndash1822 of edible stabilized rice bran as reportedearlier[34] The variation may be attributed to the source of bran and their processing

conditions Similar trend was observed for water solubility Increase in watersolubility of stabilized rice bran may be due to the solubilization of the starchcomponent during heat processing of rice bran by dry heat and extrusion

stabilization A significant decrease in fat absorption characteristics of rice branafter heat treatment was observed which may be due to the changes in bed porosity

and pore size of rice branProtein solubility was highest (732 g100 g ) in raw rice bran and lowest (303)

in extruded rice bran indicating the occurrence of protein denaturation during heatstabilization of rice bran as has been reported earlier[3135] also Heat stabilization

of significantly ( p 005) increased the damaged starch (enzyme susceptible starch)content in rice bran as compared to raw rice bran Result of worker[35] also indicatedhigher content of damaged starch in extruded wheat bran than the raw bran The

formation of damaged starch during extrusionheat processing may be important inyeast fermentation and can act as a functional agent in bran dough[36] Color of the

bran as observed visually extruded bran was dark brown in color whereas the dryheat treated bran was just brown and the raw bran was light tan in color Thechanges in color upon heating may be attributed to the formation of Maillard

reaction compounds during extrusion and partly to the solubilization of colorpigments of raw bran

To evaluate the effectiveness of rice bran stabilization methods (dry heat andextrusion processing) a storage study was carried out The changes in free fatty

acid (FFA) contents recorded during storage are presented in Table 4 Stabilizationmethods and storage period significantly ( plt 005) affected the rate of production offree fatty acids A highly significant increase in FFA was observed in raw rice bran

during storage period FFA content in raw rice bran increased from an initial level of405ndash6460 at 60 days of storage This phenomena is typical of raw rice bran and

results in the development of hydrolytic rancidity in unstabilized rice bran[11] Thishas been attributed to the presence of active inherent lipase system of rice bran whichhydrolyses the oil free fatty acids and glycerol and renders bran unfit for oil

Table 4 Effect of the methods of stabilization and storage period on the development

of free fatty acids (FFAs) in rice bran

Methods of

stabilization

Free fatty acids kg100 kg bran

storage period (days)

0 15 30 45 60

RRB 405 1358 2046 3775 6460

DHTRB 366 375 379 570 915

ERB 385 408 422 420 410

CD at P 005 methods of stabilizationfrac14 0399

CD at P 005 storage periodfrac14 0515

CD at P 005 methods storage periodfrac14 0893

RRB raw rice bran DHT dry heat treated rice bran ERB extruded rice bran

Physico-Chemical Characteristics of Rice Bran 611

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

ORDER REPRINTS

extraction and human consumption Dry heat method of stabilization restricted thedevelopment of FFAs up to 30 days of storage and thereafter a significant increasewas observed This increase in FFAs content of bran may be attributed to thepresence of residual lipolytic activity of enzyme lipase which increased underfavorable conditions during storage Bran might have absorbed some moistureduring storage thereby favoring the lipolytic activity This type of behavior withdry-heat treated rice bran was attributed to the incomplete destruction of lipase bydry heat method and increase in moisture content of rice bran during storage[37]

By extrusion stabilization method the free fatty acid content of rice bran did notincrease significantly ( pgt 005) even at 60 days of storage indicating that theextrusion processing of rice bran is more effective in destroying the lipolytic systemof rice bran than the dry heat method The capability of the extruder in inactivat-ing the fat hydrolyzing enzymes of rice bran has also been reported earlier[911]

Less then 5 FFAs are stated to be desirable in economic refining of oil[38]

Sensory analysis[11] revealed that experienced panelists could not distinguish rancidbran from nonrancid bran until the level of free fatty acids exceeded 15However the level of fatty acids in bran that is considered acceptable for humanconsumption is 4 according to US Standards[8]

CONCLUSION

From the present investigation it can be concluded that the functional propertiessuch as water absorption water solubility bulk density and enzyme susceptiblestarch of rice bran improved significantly after stabilization However the increaseswere more pronounced in extrusion stabilized rice bran On the other hand extrusionstabilized rice bran exhibited lower fat absorption and fat solubility than dryheat stabilized rice bran The improvement in shelf life was also much higher forthe rice bran stabilized by using extrusion technology than by dry heat treatment

REFERENCES

1 Gujral HS Singh N Extrusion behavior and product characteristics of brawnand milled rice grits International Journal of Food Properties 2002 5 307

2 Gupta HP Rice bran offers India and oil source J Am Oil Chem Soc 198966 (1) 62

3 Pillaiyar P Rice bran as feed and food The Int J Nutr Dietet 1981 18 1094 Mitsuda H Yasumato K Iwami K Analysis of volatile components in

rice bran Agric Biol Chem 1968 32 4535 Sharma HR Effect of Stabilized Rice Bran and Fenugreek (Trigonella foenum

graecum) Flour on the Physico-Chemical Rheological and BakingCharacteristics of Wheat Flour PhD theses G B Pant University of Agricamp Tech Pant Nagar Pantnagar-263 145 India

6 Luh BS Introduction In Rice Utilization Luh BS Ed AVI PublishingCompany Inc Westport CT 1991 Vol II 1ndash7

612 Sharma Chauhan and Agrawal

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

ORDER REPRINTS

7 Slavin JL Lampe JW Health benefits of rice bran in human nutrition

Cereal Foods World 1992 37 7608 Saunders RM Rice bran composition and potential food uses Food Reviews

International 1986 1 4659 Randall JM Sayre RN Schultz WG Fong RY Mossman AP

Tribelhorn RE Saunders RM Rice bran stabilization by extrusion cooking

for extraction of edible oil Journal of Food Science 1985 50 36110 Desikachar HSR Status Report Preservation of byproducts of rice milling

In Rice Byproducts Preservation Proceedings of Byproducts Utilization

International Conference Valencia Spain Sept 30ndashOct 2 1974 Barber S

Tortosa E Eds Valencia Institute for Agriculture Chemistry and Food

Technology 1977 Vol II 1ndash3211 Martin D Gober JS Selhako G Verma L Wells JH Optimizing rice

bran stabilization by extrusion cooking Lousiana Agraculture 1993 30 1312 AACC Approved Methods of the American Association of Cereal Chemist 8th

Ed The Association St Paul MN 198313 Goering HK Soest PJ Forage fiber analysis (apparatus reagent processing

and some applications) Agriculture Handbook No 379 Agricultural Research

Series United States Department of Agriculture 1970 11214 Sharma RD Hypocholesterolemic activity of some Indian gums Nutrition

Research 1986 4 38115 Carpenter KJ Corrected straight acids Procedure for determination of

available lysine in foods Biochem Journal 1960 77 60416 Haug W Lantzsch HJ Sensitive method for the determination of phytate

in cereal and cereal products J Sci Food Agric 1983 34 142317 Narain M Siripurapu SCB Jha M Dwiviedi VK Physico-thermal

properties of rice bran J Food Sci Technol 1978 15 1818 Sosuliski FW The centrifuge method for the flour water absorption in hard

red spring wheat Cereal Chem 1962 39 34419 Lin MJ Humbert ES Sosuliski FW Certain functional properties of

sunflower meal products J Food Sci 1974 39 36820 Inklaar PA Fortuin J Determining the emulsifing and emulsion stabilizing

capacity of protein meal additives Food Technology 1969 23 10321 Kim CJ Byun SM Cheigh HS Kwon TW Optimization of extrusion

bran stabilization process Journal of Food Science 1987a 52 135522 Kim CJ Byun SM Cheigh HS Kwon TW Compression of solvent

extraction characteristics of rice bran pre-treated by hot air drying steam

cooking and extraction J Am Oil Chem Soc 1987b 64 51423 Camire ME Flint SI Thermal processing effects on dietary fiber

composition and hydration capacity in corn meal oat meal and potato

meals Cereal Chem 1991 68 64524 Van Soest PJ Use of detergents in the analysis of fiberous feeds 2 A rapid

method for the determination of fiber and lignin J Assoc Off Anal Chem

1963 66 93325 Matthee V Appledorff H Effect of cooking on vegetable fiber Journal of

Food Sciences 1978 43 1344

Physico-Chemical Characteristics of Rice Bran 613

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

ORDER REPRINTS

26 Bajorck I Nyman M Asp NG Extrusion cooking and dietary fiber Effectson dietary fiber contents and degradation in the rat intestinal tract CerealChem 1984 57 448

27 Siljestrom M Westerlund E Bjorck I Holm J Asp NG Theander PThe effect of various thermal processes on dietary fiber and starch content ofwhole grain wheat and white flour J Cereal Sci 1986 4 315

28 Aoe S Nakapka M Ido K Tamai Y Ohata F Anano Y Availability ofdietary fiber in extruded wheat bran and apparent digestibility in rates ofcoexisting nutrients Cereal Chem 1989 66 252

29 Theander O Torrie JH Studies on chemical modifications in heat processedstarch and wheat flour StarchStaerke 1987 39 88

30 Babcock D Rice bran as a source of dietary fiber Cereal Foods World 198732 538

31 Cheftel JC Nutritional aspects of extrusion cooking Food Chem 198630 263

32 Chauhan GS Verma NS Bains GS Effect of extrusion process on thenutritional quality of rice legume blend Die Nahrung 1988 32 43

33 Asp NG Bjorck IB Nutritional properties of extruded foods In ExtrusionCooking Mercier C Linko P Harper JM Eds American Association ofCereal Chemists St Paul MN 1989 399ndash434

34 James C Sloan S Functional properties of rice bran in model system Journalof Food Science 1984 49 310

35 Wang WM Klopfestein CF Ponte JG Jr Effects of twin screw extrusionon the physical properties of dietary fiber and other components of wholewheat and wheat bran and on the baking quality of wheat bran Cereal Chem1993 76 707

36 Defloor I De Geest C Schellenkens M Martens A Delour JAEmulsifiers andor extruded starch in the production of bread from cassavaCereal Chem 1991 68 323

37 Loeb JE Mayne RY Effect of moisture on micro flora and formation offree fatty acids in rice bran Cereal Chem 1952 29 163

38 Sayre RN Saunders RM Enochian RV Shultz WG Beagle ECReview of rice bran stabilization systems with emphasis on extrusion cookingCereal Food World 1982 7 317

614 Sharma Chauhan and Agrawal

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

Request PermissionOrder Reprints

Reprints of this article can also be ordered at

httpwwwdekkercomservletproductDOI101081JFP200033047

Request Permission or Order Reprints Instantly

Interested in copying and sharing this article In most cases US Copyright Law requires that you get permission from the articlersquos rightsholder before using copyrighted content

All information and materials found in this article including but not limited to text trademarks patents logos graphics and images (the Materials) are the copyrighted works and other forms of intellectual property of Marcel Dekker Inc or its licensors All rights not expressly granted are reserved

Get permission to lawfully reproduce and distribute the Materials or order reprints quickly and painlessly Simply click on the Request Permission Order Reprints link below and follow the instructions Visit the US Copyright Office for information on Fair Use limitations of US copyright law Please refer to The Association of American Publishersrsquo (AAP) website for guidelines on Fair Use in the Classroom

The Materials are for your personal use only and cannot be reformatted reposted resold or distributed by electronic means or otherwise without permission from Marcel Dekker Inc Marcel Dekker Inc grants you the limited right to display the Materials only on your personal computer or personal wireless device and to copy and download single copies of such Materials provided that any copyright trademark or other notice appearing on such Materials is also retained by displayed copied or downloaded as part of the Materials and is not removed or obscured and provided you do not edit modify alter or enhance the Materials Please refer to our Website User Agreement for more details

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

ORDER REPRINTS

Table

3

Effectofmethodofstabilizationonthefunctionalcharacteristics

ofrice

Methodsof

stabilization

Bulk

density

(gm

L)

Waterabsorption

(g100g)

Watersolubility

(g100g)

Fatabsorption

(g100g)

Protein

solubility

(g100g)

Damaged

starch

(g100g)

Visual

color

RRB

0500

14368

757

9632

732

082

Lighttan

DHTRB

0548

15691

934

8128

444

325

Brown

ERB

0593

17093

933

7260

303

507

Dark

brown

CD

atP005

0026

3696

0608

2756

0635

0300

mdash

Data

reported

are

theaverageoftriplicate

determinations

RRBraw

rice

branDHTdry

heattreatedrice

branERBextruded

rice

bran

610 Sharma Chauhan and Agrawal

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

ORDER REPRINTS

absorptions in the range of 2131ndash1822 of edible stabilized rice bran as reportedearlier[34] The variation may be attributed to the source of bran and their processing

conditions Similar trend was observed for water solubility Increase in watersolubility of stabilized rice bran may be due to the solubilization of the starchcomponent during heat processing of rice bran by dry heat and extrusion

stabilization A significant decrease in fat absorption characteristics of rice branafter heat treatment was observed which may be due to the changes in bed porosity

and pore size of rice branProtein solubility was highest (732 g100 g ) in raw rice bran and lowest (303)

in extruded rice bran indicating the occurrence of protein denaturation during heatstabilization of rice bran as has been reported earlier[3135] also Heat stabilization

of significantly ( p 005) increased the damaged starch (enzyme susceptible starch)content in rice bran as compared to raw rice bran Result of worker[35] also indicatedhigher content of damaged starch in extruded wheat bran than the raw bran The

formation of damaged starch during extrusionheat processing may be important inyeast fermentation and can act as a functional agent in bran dough[36] Color of the

bran as observed visually extruded bran was dark brown in color whereas the dryheat treated bran was just brown and the raw bran was light tan in color Thechanges in color upon heating may be attributed to the formation of Maillard

reaction compounds during extrusion and partly to the solubilization of colorpigments of raw bran

To evaluate the effectiveness of rice bran stabilization methods (dry heat andextrusion processing) a storage study was carried out The changes in free fatty

acid (FFA) contents recorded during storage are presented in Table 4 Stabilizationmethods and storage period significantly ( plt 005) affected the rate of production offree fatty acids A highly significant increase in FFA was observed in raw rice bran

during storage period FFA content in raw rice bran increased from an initial level of405ndash6460 at 60 days of storage This phenomena is typical of raw rice bran and

results in the development of hydrolytic rancidity in unstabilized rice bran[11] Thishas been attributed to the presence of active inherent lipase system of rice bran whichhydrolyses the oil free fatty acids and glycerol and renders bran unfit for oil

Table 4 Effect of the methods of stabilization and storage period on the development

of free fatty acids (FFAs) in rice bran

Methods of

stabilization

Free fatty acids kg100 kg bran

storage period (days)

0 15 30 45 60

RRB 405 1358 2046 3775 6460

DHTRB 366 375 379 570 915

ERB 385 408 422 420 410

CD at P 005 methods of stabilizationfrac14 0399

CD at P 005 storage periodfrac14 0515

CD at P 005 methods storage periodfrac14 0893

RRB raw rice bran DHT dry heat treated rice bran ERB extruded rice bran

Physico-Chemical Characteristics of Rice Bran 611

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

ORDER REPRINTS

extraction and human consumption Dry heat method of stabilization restricted thedevelopment of FFAs up to 30 days of storage and thereafter a significant increasewas observed This increase in FFAs content of bran may be attributed to thepresence of residual lipolytic activity of enzyme lipase which increased underfavorable conditions during storage Bran might have absorbed some moistureduring storage thereby favoring the lipolytic activity This type of behavior withdry-heat treated rice bran was attributed to the incomplete destruction of lipase bydry heat method and increase in moisture content of rice bran during storage[37]

By extrusion stabilization method the free fatty acid content of rice bran did notincrease significantly ( pgt 005) even at 60 days of storage indicating that theextrusion processing of rice bran is more effective in destroying the lipolytic systemof rice bran than the dry heat method The capability of the extruder in inactivat-ing the fat hydrolyzing enzymes of rice bran has also been reported earlier[911]

Less then 5 FFAs are stated to be desirable in economic refining of oil[38]

Sensory analysis[11] revealed that experienced panelists could not distinguish rancidbran from nonrancid bran until the level of free fatty acids exceeded 15However the level of fatty acids in bran that is considered acceptable for humanconsumption is 4 according to US Standards[8]

CONCLUSION

From the present investigation it can be concluded that the functional propertiessuch as water absorption water solubility bulk density and enzyme susceptiblestarch of rice bran improved significantly after stabilization However the increaseswere more pronounced in extrusion stabilized rice bran On the other hand extrusionstabilized rice bran exhibited lower fat absorption and fat solubility than dryheat stabilized rice bran The improvement in shelf life was also much higher forthe rice bran stabilized by using extrusion technology than by dry heat treatment

REFERENCES

1 Gujral HS Singh N Extrusion behavior and product characteristics of brawnand milled rice grits International Journal of Food Properties 2002 5 307

2 Gupta HP Rice bran offers India and oil source J Am Oil Chem Soc 198966 (1) 62

3 Pillaiyar P Rice bran as feed and food The Int J Nutr Dietet 1981 18 1094 Mitsuda H Yasumato K Iwami K Analysis of volatile components in

rice bran Agric Biol Chem 1968 32 4535 Sharma HR Effect of Stabilized Rice Bran and Fenugreek (Trigonella foenum

graecum) Flour on the Physico-Chemical Rheological and BakingCharacteristics of Wheat Flour PhD theses G B Pant University of Agricamp Tech Pant Nagar Pantnagar-263 145 India

6 Luh BS Introduction In Rice Utilization Luh BS Ed AVI PublishingCompany Inc Westport CT 1991 Vol II 1ndash7

612 Sharma Chauhan and Agrawal

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

ORDER REPRINTS

7 Slavin JL Lampe JW Health benefits of rice bran in human nutrition

Cereal Foods World 1992 37 7608 Saunders RM Rice bran composition and potential food uses Food Reviews

International 1986 1 4659 Randall JM Sayre RN Schultz WG Fong RY Mossman AP

Tribelhorn RE Saunders RM Rice bran stabilization by extrusion cooking

for extraction of edible oil Journal of Food Science 1985 50 36110 Desikachar HSR Status Report Preservation of byproducts of rice milling

In Rice Byproducts Preservation Proceedings of Byproducts Utilization

International Conference Valencia Spain Sept 30ndashOct 2 1974 Barber S

Tortosa E Eds Valencia Institute for Agriculture Chemistry and Food

Technology 1977 Vol II 1ndash3211 Martin D Gober JS Selhako G Verma L Wells JH Optimizing rice

bran stabilization by extrusion cooking Lousiana Agraculture 1993 30 1312 AACC Approved Methods of the American Association of Cereal Chemist 8th

Ed The Association St Paul MN 198313 Goering HK Soest PJ Forage fiber analysis (apparatus reagent processing

and some applications) Agriculture Handbook No 379 Agricultural Research

Series United States Department of Agriculture 1970 11214 Sharma RD Hypocholesterolemic activity of some Indian gums Nutrition

Research 1986 4 38115 Carpenter KJ Corrected straight acids Procedure for determination of

available lysine in foods Biochem Journal 1960 77 60416 Haug W Lantzsch HJ Sensitive method for the determination of phytate

in cereal and cereal products J Sci Food Agric 1983 34 142317 Narain M Siripurapu SCB Jha M Dwiviedi VK Physico-thermal

properties of rice bran J Food Sci Technol 1978 15 1818 Sosuliski FW The centrifuge method for the flour water absorption in hard

red spring wheat Cereal Chem 1962 39 34419 Lin MJ Humbert ES Sosuliski FW Certain functional properties of

sunflower meal products J Food Sci 1974 39 36820 Inklaar PA Fortuin J Determining the emulsifing and emulsion stabilizing

capacity of protein meal additives Food Technology 1969 23 10321 Kim CJ Byun SM Cheigh HS Kwon TW Optimization of extrusion

bran stabilization process Journal of Food Science 1987a 52 135522 Kim CJ Byun SM Cheigh HS Kwon TW Compression of solvent

extraction characteristics of rice bran pre-treated by hot air drying steam

cooking and extraction J Am Oil Chem Soc 1987b 64 51423 Camire ME Flint SI Thermal processing effects on dietary fiber

composition and hydration capacity in corn meal oat meal and potato

meals Cereal Chem 1991 68 64524 Van Soest PJ Use of detergents in the analysis of fiberous feeds 2 A rapid

method for the determination of fiber and lignin J Assoc Off Anal Chem

1963 66 93325 Matthee V Appledorff H Effect of cooking on vegetable fiber Journal of

Food Sciences 1978 43 1344

Physico-Chemical Characteristics of Rice Bran 613

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

ORDER REPRINTS

26 Bajorck I Nyman M Asp NG Extrusion cooking and dietary fiber Effectson dietary fiber contents and degradation in the rat intestinal tract CerealChem 1984 57 448

27 Siljestrom M Westerlund E Bjorck I Holm J Asp NG Theander PThe effect of various thermal processes on dietary fiber and starch content ofwhole grain wheat and white flour J Cereal Sci 1986 4 315

28 Aoe S Nakapka M Ido K Tamai Y Ohata F Anano Y Availability ofdietary fiber in extruded wheat bran and apparent digestibility in rates ofcoexisting nutrients Cereal Chem 1989 66 252

29 Theander O Torrie JH Studies on chemical modifications in heat processedstarch and wheat flour StarchStaerke 1987 39 88

30 Babcock D Rice bran as a source of dietary fiber Cereal Foods World 198732 538

31 Cheftel JC Nutritional aspects of extrusion cooking Food Chem 198630 263

32 Chauhan GS Verma NS Bains GS Effect of extrusion process on thenutritional quality of rice legume blend Die Nahrung 1988 32 43

33 Asp NG Bjorck IB Nutritional properties of extruded foods In ExtrusionCooking Mercier C Linko P Harper JM Eds American Association ofCereal Chemists St Paul MN 1989 399ndash434

34 James C Sloan S Functional properties of rice bran in model system Journalof Food Science 1984 49 310

35 Wang WM Klopfestein CF Ponte JG Jr Effects of twin screw extrusionon the physical properties of dietary fiber and other components of wholewheat and wheat bran and on the baking quality of wheat bran Cereal Chem1993 76 707

36 Defloor I De Geest C Schellenkens M Martens A Delour JAEmulsifiers andor extruded starch in the production of bread from cassavaCereal Chem 1991 68 323

37 Loeb JE Mayne RY Effect of moisture on micro flora and formation offree fatty acids in rice bran Cereal Chem 1952 29 163

38 Sayre RN Saunders RM Enochian RV Shultz WG Beagle ECReview of rice bran stabilization systems with emphasis on extrusion cookingCereal Food World 1982 7 317

614 Sharma Chauhan and Agrawal

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

Request PermissionOrder Reprints

Reprints of this article can also be ordered at

httpwwwdekkercomservletproductDOI101081JFP200033047

Request Permission or Order Reprints Instantly

Interested in copying and sharing this article In most cases US Copyright Law requires that you get permission from the articlersquos rightsholder before using copyrighted content

All information and materials found in this article including but not limited to text trademarks patents logos graphics and images (the Materials) are the copyrighted works and other forms of intellectual property of Marcel Dekker Inc or its licensors All rights not expressly granted are reserved

Get permission to lawfully reproduce and distribute the Materials or order reprints quickly and painlessly Simply click on the Request Permission Order Reprints link below and follow the instructions Visit the US Copyright Office for information on Fair Use limitations of US copyright law Please refer to The Association of American Publishersrsquo (AAP) website for guidelines on Fair Use in the Classroom

The Materials are for your personal use only and cannot be reformatted reposted resold or distributed by electronic means or otherwise without permission from Marcel Dekker Inc Marcel Dekker Inc grants you the limited right to display the Materials only on your personal computer or personal wireless device and to copy and download single copies of such Materials provided that any copyright trademark or other notice appearing on such Materials is also retained by displayed copied or downloaded as part of the Materials and is not removed or obscured and provided you do not edit modify alter or enhance the Materials Please refer to our Website User Agreement for more details

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

ORDER REPRINTS

absorptions in the range of 2131ndash1822 of edible stabilized rice bran as reportedearlier[34] The variation may be attributed to the source of bran and their processing

conditions Similar trend was observed for water solubility Increase in watersolubility of stabilized rice bran may be due to the solubilization of the starchcomponent during heat processing of rice bran by dry heat and extrusion

stabilization A significant decrease in fat absorption characteristics of rice branafter heat treatment was observed which may be due to the changes in bed porosity

and pore size of rice branProtein solubility was highest (732 g100 g ) in raw rice bran and lowest (303)

in extruded rice bran indicating the occurrence of protein denaturation during heatstabilization of rice bran as has been reported earlier[3135] also Heat stabilization

of significantly ( p 005) increased the damaged starch (enzyme susceptible starch)content in rice bran as compared to raw rice bran Result of worker[35] also indicatedhigher content of damaged starch in extruded wheat bran than the raw bran The

formation of damaged starch during extrusionheat processing may be important inyeast fermentation and can act as a functional agent in bran dough[36] Color of the

bran as observed visually extruded bran was dark brown in color whereas the dryheat treated bran was just brown and the raw bran was light tan in color Thechanges in color upon heating may be attributed to the formation of Maillard

reaction compounds during extrusion and partly to the solubilization of colorpigments of raw bran

To evaluate the effectiveness of rice bran stabilization methods (dry heat andextrusion processing) a storage study was carried out The changes in free fatty

acid (FFA) contents recorded during storage are presented in Table 4 Stabilizationmethods and storage period significantly ( plt 005) affected the rate of production offree fatty acids A highly significant increase in FFA was observed in raw rice bran

during storage period FFA content in raw rice bran increased from an initial level of405ndash6460 at 60 days of storage This phenomena is typical of raw rice bran and

results in the development of hydrolytic rancidity in unstabilized rice bran[11] Thishas been attributed to the presence of active inherent lipase system of rice bran whichhydrolyses the oil free fatty acids and glycerol and renders bran unfit for oil

Table 4 Effect of the methods of stabilization and storage period on the development

of free fatty acids (FFAs) in rice bran

Methods of

stabilization

Free fatty acids kg100 kg bran

storage period (days)

0 15 30 45 60

RRB 405 1358 2046 3775 6460

DHTRB 366 375 379 570 915

ERB 385 408 422 420 410

CD at P 005 methods of stabilizationfrac14 0399

CD at P 005 storage periodfrac14 0515

CD at P 005 methods storage periodfrac14 0893

RRB raw rice bran DHT dry heat treated rice bran ERB extruded rice bran

Physico-Chemical Characteristics of Rice Bran 611

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

ORDER REPRINTS

extraction and human consumption Dry heat method of stabilization restricted thedevelopment of FFAs up to 30 days of storage and thereafter a significant increasewas observed This increase in FFAs content of bran may be attributed to thepresence of residual lipolytic activity of enzyme lipase which increased underfavorable conditions during storage Bran might have absorbed some moistureduring storage thereby favoring the lipolytic activity This type of behavior withdry-heat treated rice bran was attributed to the incomplete destruction of lipase bydry heat method and increase in moisture content of rice bran during storage[37]

By extrusion stabilization method the free fatty acid content of rice bran did notincrease significantly ( pgt 005) even at 60 days of storage indicating that theextrusion processing of rice bran is more effective in destroying the lipolytic systemof rice bran than the dry heat method The capability of the extruder in inactivat-ing the fat hydrolyzing enzymes of rice bran has also been reported earlier[911]

Less then 5 FFAs are stated to be desirable in economic refining of oil[38]

Sensory analysis[11] revealed that experienced panelists could not distinguish rancidbran from nonrancid bran until the level of free fatty acids exceeded 15However the level of fatty acids in bran that is considered acceptable for humanconsumption is 4 according to US Standards[8]

CONCLUSION

From the present investigation it can be concluded that the functional propertiessuch as water absorption water solubility bulk density and enzyme susceptiblestarch of rice bran improved significantly after stabilization However the increaseswere more pronounced in extrusion stabilized rice bran On the other hand extrusionstabilized rice bran exhibited lower fat absorption and fat solubility than dryheat stabilized rice bran The improvement in shelf life was also much higher forthe rice bran stabilized by using extrusion technology than by dry heat treatment

REFERENCES

1 Gujral HS Singh N Extrusion behavior and product characteristics of brawnand milled rice grits International Journal of Food Properties 2002 5 307

2 Gupta HP Rice bran offers India and oil source J Am Oil Chem Soc 198966 (1) 62

3 Pillaiyar P Rice bran as feed and food The Int J Nutr Dietet 1981 18 1094 Mitsuda H Yasumato K Iwami K Analysis of volatile components in

rice bran Agric Biol Chem 1968 32 4535 Sharma HR Effect of Stabilized Rice Bran and Fenugreek (Trigonella foenum

graecum) Flour on the Physico-Chemical Rheological and BakingCharacteristics of Wheat Flour PhD theses G B Pant University of Agricamp Tech Pant Nagar Pantnagar-263 145 India

6 Luh BS Introduction In Rice Utilization Luh BS Ed AVI PublishingCompany Inc Westport CT 1991 Vol II 1ndash7

612 Sharma Chauhan and Agrawal

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

ORDER REPRINTS

7 Slavin JL Lampe JW Health benefits of rice bran in human nutrition

Cereal Foods World 1992 37 7608 Saunders RM Rice bran composition and potential food uses Food Reviews

International 1986 1 4659 Randall JM Sayre RN Schultz WG Fong RY Mossman AP

Tribelhorn RE Saunders RM Rice bran stabilization by extrusion cooking

for extraction of edible oil Journal of Food Science 1985 50 36110 Desikachar HSR Status Report Preservation of byproducts of rice milling

In Rice Byproducts Preservation Proceedings of Byproducts Utilization

International Conference Valencia Spain Sept 30ndashOct 2 1974 Barber S

Tortosa E Eds Valencia Institute for Agriculture Chemistry and Food

Technology 1977 Vol II 1ndash3211 Martin D Gober JS Selhako G Verma L Wells JH Optimizing rice

bran stabilization by extrusion cooking Lousiana Agraculture 1993 30 1312 AACC Approved Methods of the American Association of Cereal Chemist 8th

Ed The Association St Paul MN 198313 Goering HK Soest PJ Forage fiber analysis (apparatus reagent processing

and some applications) Agriculture Handbook No 379 Agricultural Research

Series United States Department of Agriculture 1970 11214 Sharma RD Hypocholesterolemic activity of some Indian gums Nutrition

Research 1986 4 38115 Carpenter KJ Corrected straight acids Procedure for determination of

available lysine in foods Biochem Journal 1960 77 60416 Haug W Lantzsch HJ Sensitive method for the determination of phytate

in cereal and cereal products J Sci Food Agric 1983 34 142317 Narain M Siripurapu SCB Jha M Dwiviedi VK Physico-thermal

properties of rice bran J Food Sci Technol 1978 15 1818 Sosuliski FW The centrifuge method for the flour water absorption in hard

red spring wheat Cereal Chem 1962 39 34419 Lin MJ Humbert ES Sosuliski FW Certain functional properties of

sunflower meal products J Food Sci 1974 39 36820 Inklaar PA Fortuin J Determining the emulsifing and emulsion stabilizing

capacity of protein meal additives Food Technology 1969 23 10321 Kim CJ Byun SM Cheigh HS Kwon TW Optimization of extrusion

bran stabilization process Journal of Food Science 1987a 52 135522 Kim CJ Byun SM Cheigh HS Kwon TW Compression of solvent

extraction characteristics of rice bran pre-treated by hot air drying steam

cooking and extraction J Am Oil Chem Soc 1987b 64 51423 Camire ME Flint SI Thermal processing effects on dietary fiber

composition and hydration capacity in corn meal oat meal and potato

meals Cereal Chem 1991 68 64524 Van Soest PJ Use of detergents in the analysis of fiberous feeds 2 A rapid

method for the determination of fiber and lignin J Assoc Off Anal Chem

1963 66 93325 Matthee V Appledorff H Effect of cooking on vegetable fiber Journal of

Food Sciences 1978 43 1344

Physico-Chemical Characteristics of Rice Bran 613

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] at

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ORDER REPRINTS

26 Bajorck I Nyman M Asp NG Extrusion cooking and dietary fiber Effectson dietary fiber contents and degradation in the rat intestinal tract CerealChem 1984 57 448

27 Siljestrom M Westerlund E Bjorck I Holm J Asp NG Theander PThe effect of various thermal processes on dietary fiber and starch content ofwhole grain wheat and white flour J Cereal Sci 1986 4 315

28 Aoe S Nakapka M Ido K Tamai Y Ohata F Anano Y Availability ofdietary fiber in extruded wheat bran and apparent digestibility in rates ofcoexisting nutrients Cereal Chem 1989 66 252

29 Theander O Torrie JH Studies on chemical modifications in heat processedstarch and wheat flour StarchStaerke 1987 39 88

30 Babcock D Rice bran as a source of dietary fiber Cereal Foods World 198732 538

31 Cheftel JC Nutritional aspects of extrusion cooking Food Chem 198630 263

32 Chauhan GS Verma NS Bains GS Effect of extrusion process on thenutritional quality of rice legume blend Die Nahrung 1988 32 43

33 Asp NG Bjorck IB Nutritional properties of extruded foods In ExtrusionCooking Mercier C Linko P Harper JM Eds American Association ofCereal Chemists St Paul MN 1989 399ndash434

34 James C Sloan S Functional properties of rice bran in model system Journalof Food Science 1984 49 310

35 Wang WM Klopfestein CF Ponte JG Jr Effects of twin screw extrusionon the physical properties of dietary fiber and other components of wholewheat and wheat bran and on the baking quality of wheat bran Cereal Chem1993 76 707

36 Defloor I De Geest C Schellenkens M Martens A Delour JAEmulsifiers andor extruded starch in the production of bread from cassavaCereal Chem 1991 68 323

37 Loeb JE Mayne RY Effect of moisture on micro flora and formation offree fatty acids in rice bran Cereal Chem 1952 29 163

38 Sayre RN Saunders RM Enochian RV Shultz WG Beagle ECReview of rice bran stabilization systems with emphasis on extrusion cookingCereal Food World 1982 7 317

614 Sharma Chauhan and Agrawal

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

Request PermissionOrder Reprints

Reprints of this article can also be ordered at

httpwwwdekkercomservletproductDOI101081JFP200033047

Request Permission or Order Reprints Instantly

Interested in copying and sharing this article In most cases US Copyright Law requires that you get permission from the articlersquos rightsholder before using copyrighted content

All information and materials found in this article including but not limited to text trademarks patents logos graphics and images (the Materials) are the copyrighted works and other forms of intellectual property of Marcel Dekker Inc or its licensors All rights not expressly granted are reserved

Get permission to lawfully reproduce and distribute the Materials or order reprints quickly and painlessly Simply click on the Request Permission Order Reprints link below and follow the instructions Visit the US Copyright Office for information on Fair Use limitations of US copyright law Please refer to The Association of American Publishersrsquo (AAP) website for guidelines on Fair Use in the Classroom

The Materials are for your personal use only and cannot be reformatted reposted resold or distributed by electronic means or otherwise without permission from Marcel Dekker Inc Marcel Dekker Inc grants you the limited right to display the Materials only on your personal computer or personal wireless device and to copy and download single copies of such Materials provided that any copyright trademark or other notice appearing on such Materials is also retained by displayed copied or downloaded as part of the Materials and is not removed or obscured and provided you do not edit modify alter or enhance the Materials Please refer to our Website User Agreement for more details

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ded

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rsity

] at

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ctob

er 2

014

ORDER REPRINTS

extraction and human consumption Dry heat method of stabilization restricted thedevelopment of FFAs up to 30 days of storage and thereafter a significant increasewas observed This increase in FFAs content of bran may be attributed to thepresence of residual lipolytic activity of enzyme lipase which increased underfavorable conditions during storage Bran might have absorbed some moistureduring storage thereby favoring the lipolytic activity This type of behavior withdry-heat treated rice bran was attributed to the incomplete destruction of lipase bydry heat method and increase in moisture content of rice bran during storage[37]

By extrusion stabilization method the free fatty acid content of rice bran did notincrease significantly ( pgt 005) even at 60 days of storage indicating that theextrusion processing of rice bran is more effective in destroying the lipolytic systemof rice bran than the dry heat method The capability of the extruder in inactivat-ing the fat hydrolyzing enzymes of rice bran has also been reported earlier[911]

Less then 5 FFAs are stated to be desirable in economic refining of oil[38]

Sensory analysis[11] revealed that experienced panelists could not distinguish rancidbran from nonrancid bran until the level of free fatty acids exceeded 15However the level of fatty acids in bran that is considered acceptable for humanconsumption is 4 according to US Standards[8]

CONCLUSION

From the present investigation it can be concluded that the functional propertiessuch as water absorption water solubility bulk density and enzyme susceptiblestarch of rice bran improved significantly after stabilization However the increaseswere more pronounced in extrusion stabilized rice bran On the other hand extrusionstabilized rice bran exhibited lower fat absorption and fat solubility than dryheat stabilized rice bran The improvement in shelf life was also much higher forthe rice bran stabilized by using extrusion technology than by dry heat treatment

REFERENCES

1 Gujral HS Singh N Extrusion behavior and product characteristics of brawnand milled rice grits International Journal of Food Properties 2002 5 307

2 Gupta HP Rice bran offers India and oil source J Am Oil Chem Soc 198966 (1) 62

3 Pillaiyar P Rice bran as feed and food The Int J Nutr Dietet 1981 18 1094 Mitsuda H Yasumato K Iwami K Analysis of volatile components in

rice bran Agric Biol Chem 1968 32 4535 Sharma HR Effect of Stabilized Rice Bran and Fenugreek (Trigonella foenum

graecum) Flour on the Physico-Chemical Rheological and BakingCharacteristics of Wheat Flour PhD theses G B Pant University of Agricamp Tech Pant Nagar Pantnagar-263 145 India

6 Luh BS Introduction In Rice Utilization Luh BS Ed AVI PublishingCompany Inc Westport CT 1991 Vol II 1ndash7

612 Sharma Chauhan and Agrawal

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rsity

] at

14

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ORDER REPRINTS

7 Slavin JL Lampe JW Health benefits of rice bran in human nutrition

Cereal Foods World 1992 37 7608 Saunders RM Rice bran composition and potential food uses Food Reviews

International 1986 1 4659 Randall JM Sayre RN Schultz WG Fong RY Mossman AP

Tribelhorn RE Saunders RM Rice bran stabilization by extrusion cooking

for extraction of edible oil Journal of Food Science 1985 50 36110 Desikachar HSR Status Report Preservation of byproducts of rice milling

In Rice Byproducts Preservation Proceedings of Byproducts Utilization

International Conference Valencia Spain Sept 30ndashOct 2 1974 Barber S

Tortosa E Eds Valencia Institute for Agriculture Chemistry and Food

Technology 1977 Vol II 1ndash3211 Martin D Gober JS Selhako G Verma L Wells JH Optimizing rice

bran stabilization by extrusion cooking Lousiana Agraculture 1993 30 1312 AACC Approved Methods of the American Association of Cereal Chemist 8th

Ed The Association St Paul MN 198313 Goering HK Soest PJ Forage fiber analysis (apparatus reagent processing

and some applications) Agriculture Handbook No 379 Agricultural Research

Series United States Department of Agriculture 1970 11214 Sharma RD Hypocholesterolemic activity of some Indian gums Nutrition

Research 1986 4 38115 Carpenter KJ Corrected straight acids Procedure for determination of

available lysine in foods Biochem Journal 1960 77 60416 Haug W Lantzsch HJ Sensitive method for the determination of phytate

in cereal and cereal products J Sci Food Agric 1983 34 142317 Narain M Siripurapu SCB Jha M Dwiviedi VK Physico-thermal

properties of rice bran J Food Sci Technol 1978 15 1818 Sosuliski FW The centrifuge method for the flour water absorption in hard

red spring wheat Cereal Chem 1962 39 34419 Lin MJ Humbert ES Sosuliski FW Certain functional properties of

sunflower meal products J Food Sci 1974 39 36820 Inklaar PA Fortuin J Determining the emulsifing and emulsion stabilizing

capacity of protein meal additives Food Technology 1969 23 10321 Kim CJ Byun SM Cheigh HS Kwon TW Optimization of extrusion

bran stabilization process Journal of Food Science 1987a 52 135522 Kim CJ Byun SM Cheigh HS Kwon TW Compression of solvent

extraction characteristics of rice bran pre-treated by hot air drying steam

cooking and extraction J Am Oil Chem Soc 1987b 64 51423 Camire ME Flint SI Thermal processing effects on dietary fiber

composition and hydration capacity in corn meal oat meal and potato

meals Cereal Chem 1991 68 64524 Van Soest PJ Use of detergents in the analysis of fiberous feeds 2 A rapid

method for the determination of fiber and lignin J Assoc Off Anal Chem

1963 66 93325 Matthee V Appledorff H Effect of cooking on vegetable fiber Journal of

Food Sciences 1978 43 1344

Physico-Chemical Characteristics of Rice Bran 613

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

ORDER REPRINTS

26 Bajorck I Nyman M Asp NG Extrusion cooking and dietary fiber Effectson dietary fiber contents and degradation in the rat intestinal tract CerealChem 1984 57 448

27 Siljestrom M Westerlund E Bjorck I Holm J Asp NG Theander PThe effect of various thermal processes on dietary fiber and starch content ofwhole grain wheat and white flour J Cereal Sci 1986 4 315

28 Aoe S Nakapka M Ido K Tamai Y Ohata F Anano Y Availability ofdietary fiber in extruded wheat bran and apparent digestibility in rates ofcoexisting nutrients Cereal Chem 1989 66 252

29 Theander O Torrie JH Studies on chemical modifications in heat processedstarch and wheat flour StarchStaerke 1987 39 88

30 Babcock D Rice bran as a source of dietary fiber Cereal Foods World 198732 538

31 Cheftel JC Nutritional aspects of extrusion cooking Food Chem 198630 263

32 Chauhan GS Verma NS Bains GS Effect of extrusion process on thenutritional quality of rice legume blend Die Nahrung 1988 32 43

33 Asp NG Bjorck IB Nutritional properties of extruded foods In ExtrusionCooking Mercier C Linko P Harper JM Eds American Association ofCereal Chemists St Paul MN 1989 399ndash434

34 James C Sloan S Functional properties of rice bran in model system Journalof Food Science 1984 49 310

35 Wang WM Klopfestein CF Ponte JG Jr Effects of twin screw extrusionon the physical properties of dietary fiber and other components of wholewheat and wheat bran and on the baking quality of wheat bran Cereal Chem1993 76 707

36 Defloor I De Geest C Schellenkens M Martens A Delour JAEmulsifiers andor extruded starch in the production of bread from cassavaCereal Chem 1991 68 323

37 Loeb JE Mayne RY Effect of moisture on micro flora and formation offree fatty acids in rice bran Cereal Chem 1952 29 163

38 Sayre RN Saunders RM Enochian RV Shultz WG Beagle ECReview of rice bran stabilization systems with emphasis on extrusion cookingCereal Food World 1982 7 317

614 Sharma Chauhan and Agrawal

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

Request PermissionOrder Reprints

Reprints of this article can also be ordered at

httpwwwdekkercomservletproductDOI101081JFP200033047

Request Permission or Order Reprints Instantly

Interested in copying and sharing this article In most cases US Copyright Law requires that you get permission from the articlersquos rightsholder before using copyrighted content

All information and materials found in this article including but not limited to text trademarks patents logos graphics and images (the Materials) are the copyrighted works and other forms of intellectual property of Marcel Dekker Inc or its licensors All rights not expressly granted are reserved

Get permission to lawfully reproduce and distribute the Materials or order reprints quickly and painlessly Simply click on the Request Permission Order Reprints link below and follow the instructions Visit the US Copyright Office for information on Fair Use limitations of US copyright law Please refer to The Association of American Publishersrsquo (AAP) website for guidelines on Fair Use in the Classroom

The Materials are for your personal use only and cannot be reformatted reposted resold or distributed by electronic means or otherwise without permission from Marcel Dekker Inc Marcel Dekker Inc grants you the limited right to display the Materials only on your personal computer or personal wireless device and to copy and download single copies of such Materials provided that any copyright trademark or other notice appearing on such Materials is also retained by displayed copied or downloaded as part of the Materials and is not removed or obscured and provided you do not edit modify alter or enhance the Materials Please refer to our Website User Agreement for more details

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

ORDER REPRINTS

7 Slavin JL Lampe JW Health benefits of rice bran in human nutrition

Cereal Foods World 1992 37 7608 Saunders RM Rice bran composition and potential food uses Food Reviews

International 1986 1 4659 Randall JM Sayre RN Schultz WG Fong RY Mossman AP

Tribelhorn RE Saunders RM Rice bran stabilization by extrusion cooking

for extraction of edible oil Journal of Food Science 1985 50 36110 Desikachar HSR Status Report Preservation of byproducts of rice milling

In Rice Byproducts Preservation Proceedings of Byproducts Utilization

International Conference Valencia Spain Sept 30ndashOct 2 1974 Barber S

Tortosa E Eds Valencia Institute for Agriculture Chemistry and Food

Technology 1977 Vol II 1ndash3211 Martin D Gober JS Selhako G Verma L Wells JH Optimizing rice

bran stabilization by extrusion cooking Lousiana Agraculture 1993 30 1312 AACC Approved Methods of the American Association of Cereal Chemist 8th

Ed The Association St Paul MN 198313 Goering HK Soest PJ Forage fiber analysis (apparatus reagent processing

and some applications) Agriculture Handbook No 379 Agricultural Research

Series United States Department of Agriculture 1970 11214 Sharma RD Hypocholesterolemic activity of some Indian gums Nutrition

Research 1986 4 38115 Carpenter KJ Corrected straight acids Procedure for determination of

available lysine in foods Biochem Journal 1960 77 60416 Haug W Lantzsch HJ Sensitive method for the determination of phytate

in cereal and cereal products J Sci Food Agric 1983 34 142317 Narain M Siripurapu SCB Jha M Dwiviedi VK Physico-thermal

properties of rice bran J Food Sci Technol 1978 15 1818 Sosuliski FW The centrifuge method for the flour water absorption in hard

red spring wheat Cereal Chem 1962 39 34419 Lin MJ Humbert ES Sosuliski FW Certain functional properties of

sunflower meal products J Food Sci 1974 39 36820 Inklaar PA Fortuin J Determining the emulsifing and emulsion stabilizing

capacity of protein meal additives Food Technology 1969 23 10321 Kim CJ Byun SM Cheigh HS Kwon TW Optimization of extrusion

bran stabilization process Journal of Food Science 1987a 52 135522 Kim CJ Byun SM Cheigh HS Kwon TW Compression of solvent

extraction characteristics of rice bran pre-treated by hot air drying steam

cooking and extraction J Am Oil Chem Soc 1987b 64 51423 Camire ME Flint SI Thermal processing effects on dietary fiber

composition and hydration capacity in corn meal oat meal and potato

meals Cereal Chem 1991 68 64524 Van Soest PJ Use of detergents in the analysis of fiberous feeds 2 A rapid

method for the determination of fiber and lignin J Assoc Off Anal Chem

1963 66 93325 Matthee V Appledorff H Effect of cooking on vegetable fiber Journal of

Food Sciences 1978 43 1344

Physico-Chemical Characteristics of Rice Bran 613

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

ORDER REPRINTS

26 Bajorck I Nyman M Asp NG Extrusion cooking and dietary fiber Effectson dietary fiber contents and degradation in the rat intestinal tract CerealChem 1984 57 448

27 Siljestrom M Westerlund E Bjorck I Holm J Asp NG Theander PThe effect of various thermal processes on dietary fiber and starch content ofwhole grain wheat and white flour J Cereal Sci 1986 4 315

28 Aoe S Nakapka M Ido K Tamai Y Ohata F Anano Y Availability ofdietary fiber in extruded wheat bran and apparent digestibility in rates ofcoexisting nutrients Cereal Chem 1989 66 252

29 Theander O Torrie JH Studies on chemical modifications in heat processedstarch and wheat flour StarchStaerke 1987 39 88

30 Babcock D Rice bran as a source of dietary fiber Cereal Foods World 198732 538

31 Cheftel JC Nutritional aspects of extrusion cooking Food Chem 198630 263

32 Chauhan GS Verma NS Bains GS Effect of extrusion process on thenutritional quality of rice legume blend Die Nahrung 1988 32 43

33 Asp NG Bjorck IB Nutritional properties of extruded foods In ExtrusionCooking Mercier C Linko P Harper JM Eds American Association ofCereal Chemists St Paul MN 1989 399ndash434

34 James C Sloan S Functional properties of rice bran in model system Journalof Food Science 1984 49 310

35 Wang WM Klopfestein CF Ponte JG Jr Effects of twin screw extrusionon the physical properties of dietary fiber and other components of wholewheat and wheat bran and on the baking quality of wheat bran Cereal Chem1993 76 707

36 Defloor I De Geest C Schellenkens M Martens A Delour JAEmulsifiers andor extruded starch in the production of bread from cassavaCereal Chem 1991 68 323

37 Loeb JE Mayne RY Effect of moisture on micro flora and formation offree fatty acids in rice bran Cereal Chem 1952 29 163

38 Sayre RN Saunders RM Enochian RV Shultz WG Beagle ECReview of rice bran stabilization systems with emphasis on extrusion cookingCereal Food World 1982 7 317

614 Sharma Chauhan and Agrawal

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

Request PermissionOrder Reprints

Reprints of this article can also be ordered at

httpwwwdekkercomservletproductDOI101081JFP200033047

Request Permission or Order Reprints Instantly

Interested in copying and sharing this article In most cases US Copyright Law requires that you get permission from the articlersquos rightsholder before using copyrighted content

All information and materials found in this article including but not limited to text trademarks patents logos graphics and images (the Materials) are the copyrighted works and other forms of intellectual property of Marcel Dekker Inc or its licensors All rights not expressly granted are reserved

Get permission to lawfully reproduce and distribute the Materials or order reprints quickly and painlessly Simply click on the Request Permission Order Reprints link below and follow the instructions Visit the US Copyright Office for information on Fair Use limitations of US copyright law Please refer to The Association of American Publishersrsquo (AAP) website for guidelines on Fair Use in the Classroom

The Materials are for your personal use only and cannot be reformatted reposted resold or distributed by electronic means or otherwise without permission from Marcel Dekker Inc Marcel Dekker Inc grants you the limited right to display the Materials only on your personal computer or personal wireless device and to copy and download single copies of such Materials provided that any copyright trademark or other notice appearing on such Materials is also retained by displayed copied or downloaded as part of the Materials and is not removed or obscured and provided you do not edit modify alter or enhance the Materials Please refer to our Website User Agreement for more details

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

ORDER REPRINTS

26 Bajorck I Nyman M Asp NG Extrusion cooking and dietary fiber Effectson dietary fiber contents and degradation in the rat intestinal tract CerealChem 1984 57 448

27 Siljestrom M Westerlund E Bjorck I Holm J Asp NG Theander PThe effect of various thermal processes on dietary fiber and starch content ofwhole grain wheat and white flour J Cereal Sci 1986 4 315

28 Aoe S Nakapka M Ido K Tamai Y Ohata F Anano Y Availability ofdietary fiber in extruded wheat bran and apparent digestibility in rates ofcoexisting nutrients Cereal Chem 1989 66 252

29 Theander O Torrie JH Studies on chemical modifications in heat processedstarch and wheat flour StarchStaerke 1987 39 88

30 Babcock D Rice bran as a source of dietary fiber Cereal Foods World 198732 538

31 Cheftel JC Nutritional aspects of extrusion cooking Food Chem 198630 263

32 Chauhan GS Verma NS Bains GS Effect of extrusion process on thenutritional quality of rice legume blend Die Nahrung 1988 32 43

33 Asp NG Bjorck IB Nutritional properties of extruded foods In ExtrusionCooking Mercier C Linko P Harper JM Eds American Association ofCereal Chemists St Paul MN 1989 399ndash434

34 James C Sloan S Functional properties of rice bran in model system Journalof Food Science 1984 49 310

35 Wang WM Klopfestein CF Ponte JG Jr Effects of twin screw extrusionon the physical properties of dietary fiber and other components of wholewheat and wheat bran and on the baking quality of wheat bran Cereal Chem1993 76 707

36 Defloor I De Geest C Schellenkens M Martens A Delour JAEmulsifiers andor extruded starch in the production of bread from cassavaCereal Chem 1991 68 323

37 Loeb JE Mayne RY Effect of moisture on micro flora and formation offree fatty acids in rice bran Cereal Chem 1952 29 163

38 Sayre RN Saunders RM Enochian RV Shultz WG Beagle ECReview of rice bran stabilization systems with emphasis on extrusion cookingCereal Food World 1982 7 317

614 Sharma Chauhan and Agrawal

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

Request PermissionOrder Reprints

Reprints of this article can also be ordered at

httpwwwdekkercomservletproductDOI101081JFP200033047

Request Permission or Order Reprints Instantly

Interested in copying and sharing this article In most cases US Copyright Law requires that you get permission from the articlersquos rightsholder before using copyrighted content

All information and materials found in this article including but not limited to text trademarks patents logos graphics and images (the Materials) are the copyrighted works and other forms of intellectual property of Marcel Dekker Inc or its licensors All rights not expressly granted are reserved

Get permission to lawfully reproduce and distribute the Materials or order reprints quickly and painlessly Simply click on the Request Permission Order Reprints link below and follow the instructions Visit the US Copyright Office for information on Fair Use limitations of US copyright law Please refer to The Association of American Publishersrsquo (AAP) website for guidelines on Fair Use in the Classroom

The Materials are for your personal use only and cannot be reformatted reposted resold or distributed by electronic means or otherwise without permission from Marcel Dekker Inc Marcel Dekker Inc grants you the limited right to display the Materials only on your personal computer or personal wireless device and to copy and download single copies of such Materials provided that any copyright trademark or other notice appearing on such Materials is also retained by displayed copied or downloaded as part of the Materials and is not removed or obscured and provided you do not edit modify alter or enhance the Materials Please refer to our Website User Agreement for more details

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014

Request PermissionOrder Reprints

Reprints of this article can also be ordered at

httpwwwdekkercomservletproductDOI101081JFP200033047

Request Permission or Order Reprints Instantly

Interested in copying and sharing this article In most cases US Copyright Law requires that you get permission from the articlersquos rightsholder before using copyrighted content

All information and materials found in this article including but not limited to text trademarks patents logos graphics and images (the Materials) are the copyrighted works and other forms of intellectual property of Marcel Dekker Inc or its licensors All rights not expressly granted are reserved

Get permission to lawfully reproduce and distribute the Materials or order reprints quickly and painlessly Simply click on the Request Permission Order Reprints link below and follow the instructions Visit the US Copyright Office for information on Fair Use limitations of US copyright law Please refer to The Association of American Publishersrsquo (AAP) website for guidelines on Fair Use in the Classroom

The Materials are for your personal use only and cannot be reformatted reposted resold or distributed by electronic means or otherwise without permission from Marcel Dekker Inc Marcel Dekker Inc grants you the limited right to display the Materials only on your personal computer or personal wireless device and to copy and download single copies of such Materials provided that any copyright trademark or other notice appearing on such Materials is also retained by displayed copied or downloaded as part of the Materials and is not removed or obscured and provided you do not edit modify alter or enhance the Materials Please refer to our Website User Agreement for more details

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

14

55 1

1 O

ctob

er 2

014