Oil and Fat Technology Lectures III

8/14/2019 Oil and Fat Technology Lectures III

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OIL AND FATIL AND FATTECHNOLOGYECHNOLOGY

LECTURESECTURESIIII

( H a n d l in g & S t o r a g e o fH a n d l in g & S t o r a g e o f

O i l - B e a r i n g M a t e r i a l s - P r e t r e a t m e n t s )i l - B e a r i n g M a t e r i a l s - P r e t r e a t m e n t s ) Prof.Dr.Ayta SAYGIN GMKESENProf.Dr.Ayta SAYGIN GMKESEN

Yrd.Do.Dr.Fahri YEMOLU Yrd.Do.Dr.Fahri YEMOLU


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Handling & Storage ofandling & Storage of

Oil-Bearing Materialsil-Bearing MaterialsThe handling and storage of oil-bearing materialsThe handling and storage of oil-bearing materialsis one of the most important phases of oil seedis one of the most important phases of oil seedprocessing.processing.

The vegetable oils and feed industries areThe vegetable oils and feed industries aredependent for successful operation upondependent for successful operation uponobtaining high yields and product of goodobtaining high yields and product of goodquality from their raw material.quality from their raw material.

Excessive biological activity in the seeds, either Excessive biological activity in the seeds, either in the field prior to harvesting or subsequentlyin the field prior to harvesting or subsequentlyduring storage, will result in a reduction both induring storage, will result in a reduction both inthe quality and the yield of oil and meal.the quality and the yield of oil and meal.


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The handling and control of the rawThe handling and control of the raw

materials for the oil seed industry canmaterials for the oil seed industry canbe primarily characterized by the shortbe primarily characterized by the shortharvest season, by the necessity toharvest season, by the necessity tomove them into protected storage inmove them into protected storage inminimum time, and by the required careminimum time, and by the required carebefore they can be processed. But theybefore they can be processed. But theycan be treated and stored successfullycan be treated and stored successfullywith minimal deterioration long enoughwith minimal deterioration long enoughto allow the processing industry toto allow the processing industry tooperate throughout the year.operate throughout the year.


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Effects accompanying deterioration of seed duringEffects accompanying deterioration of seed duringstoragestorage

Respiration :Respiration : In the presence of oxygen as the oxidizingIn the presence of oxygen as the oxidizingagent, organic food stuffs are oxidized to form water andagent, organic food stuffs are oxidized to form water andcarbon dioxide as the end product.carbon dioxide as the end product.

exothermic reactionexothermic reaction

CC66 HH1212 OO66 + O+ O22 6 CO6 CO22 + 6 H+ 6 H22O + energyO + energy

Respiration intensity;Respiration intensity;

Sound seed low m.c. 0.1ml COSound seed low m.c. 0.1ml CO 22 /g seed.day /g seed.day

Damaged seed high m.c. 5.0ml CODamaged seed high m.c. 5.0ml CO 22 /g seed.day /g seed.day


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Enzymes :Enzymes :

(a)(a) LipaseLipase .. This enzyme catalyzes the reaction;This enzyme catalyzes the reaction;

11glycerol + 3 fatty acid triglycerid + 3 water glycerol + 3 fatty acid triglycerid + 3 water

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1 synthesis t.g 2 hydrolysis t.g 1 synthesis t.g 2 hydrolysis t.g

(b)(b) Catalase and peroxidaseCatalase and peroxidase .. Both of these enzymes reactBoth of these enzymes reactwith hydrogen peroxide.Catalase will decomposewith hydrogen peroxide.Catalase will decomposehydrogen peroxide while peroxidase utilizes it for hydrogen peroxide while peroxidase utilizes it for further oxidation.further oxidation.

2 hydrogen peroxide 2 water + oxygen2 hydrogen peroxide 2 water + oxygen


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Safe humidity for starchy food grainsSafe humidity for starchy food grains

16%16%

Oil content of soybean . 22%Oil content of soybean . 22%Non-oily part of soybean . 78%Non-oily part of soybean . 78%

Critical moisture level 0.78 x 16% =Critical moisture level 0.78 x 16% = 12.5%12.5%


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CML of oil seedsCML of oil seeds

Hulls (%) Fat (%) CML(%)Hulls (%) Fat (%) CML(%)Rape seedRape seed 14 40 7.014 40 7.0

Palm kernelPalm kernel

- 52 8.0- 52 8.0

Sunflower seedSunflower seed 28 43 8.528 43 8.5CottonseedCottonseed 48 18 10.048 18 10.0Soya beansSoya beans 8 20 12.08 20 12.0


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Influence of temperature.Influence of temperature.

In the case of soya beans and similar oilseeds whereIn the case of soya beans and similar oilseeds wheredeterioration appears to b primarily a result of thedeterioration appears to b primarily a result of thegrowth of microflora, the storage temperature doesgrowth of microflora, the storage temperature doesnot appear to be a major factor.not appear to be a major factor. However, temperatureHowever, temperatureis very important factor in storage of cotton seed. Theis very important factor in storage of cotton seed. Therespiration of cotton seed is markedly temperature-respiration of cotton seed is markedly temperature-dependentdependent .. The insulating effect of linters onThe insulating effect of linters oncottonseed contributes to the peculiar tendency of cottonseed contributes to the peculiar tendency of this seed to heat in storage.this seed to heat in storage.

It is because of the undesirable effect of highIt is because of the undesirable effect of hightemperature that most seed houses are equipped withtemperature that most seed houses are equipped withaeration ducts and large ventilating blowers to coolaeration ducts and large ventilating blowers to coolthe seed.the seed.


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Storage methodStorage method Warehouses (Muskogee type seedWarehouses ( Muskogee type seed

houses)houses)Bulk storage in warehouses on flat floorsBulk storage in warehouses on flat floors

has the advantage of easy control of oilhas the advantage of easy control of oil

seeds, like cottonseeds, sunflower seed,seeds, like cottonseeds, sunflower seed,corn germ, further meals etc. To preventcorn germ, further meals etc. To preventself heating or autocombustion of theself heating or autocombustion of theseeds, recycling by horizantal and verticalseeds, recycling by horizantal and vertical

transportation means is recomended.transportation means is recomended.


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Preparation of Oil-bearingPreparation of Oil-bearingMaterialsMaterials

Cleaning foreign materials

Delinting for cottonseed lintsDehulling hulls

Flaking

Cooking moist


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CLEANING

Cleaning is important not only to ensure the good quality of the final products oil and meal but also to avoid prematurewear of the preparation equipment.

The removal of foreign materials from oil seeds is done bycleaning machines working on mechanical, pneumatic andmagnetic principles.

Cleaning machines;

ScreensAspiratorsMagnetsShape sorters


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SCREENSSCREENS

Screening is the seperation of mixtures of Screening is the seperation of mixtures of different sizes into fractions; the portiondifferent sizes into fractions; the portionstaying behind being oversize, thestaying behind being oversize, theportion passing through beingportion passing through beingundersize.undersize.Rotating screensRotating screensVibrating screensVibrating screens


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Drum screen


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Vibrating screenVibrating screen


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ASPIRATORSASPIRATORSIn order to seperate impurities or fractionsIn order to seperate impurities or fractions

of different density, pneumatic means,of different density, pneumatic means,like air nozzles and aspirators are used.like air nozzles and aspirators are used.


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MAGNETSMAGNETSPermenant or electromagnets enclosed inPermenant or electromagnets enclosed in

a rotating aluminium drum are used ina rotating aluminium drum are used infeeders to distribute the materialfeeders to distribute the materialuniformly over the whole active width of uniformly over the whole active width of the drum.The magnetic material collectedthe drum.The magnetic material collectedis removed by a blade on the ono-is removed by a blade on the ono-

magnetized half and, in this way, itmagnetized half and, in this way, itremains seperated even in the case of remains seperated even in the case of power failurepower failure


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Self cleaning rotary magnetsSelf cleaning rotary magnets

Seed inletaspirator

Rotating drum

Stationarymagnet

ronpartsCleaned seed


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DELINTINGDELINTING(for cottonseed)(for cottonseed)

cottonseed

lints (8-12%)

Hull (40-45%)

Delinting process to remove the remaining lint from cotton seed

Aims of delinting : 1)increase oil yield 2)obtain first- and second- cut linters


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Delinterelinter


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Cutting operationCutting operation

cottonseed

saws

brushdelintedseed

cut lints

seed feeder

Saw teeth


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Cottonseed Delinting EquipmentCottonseed Delinting Equipment


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DEHULLINGEHULLINGDehulling is a process of removing hulls from the oilseedsDehulling is a process of removing hulls from the oilseeds

for obtaining high quality edible oil by the processing of for obtaining high quality edible oil by the processing of kernels. This reduces fibrous content of the meal andkernels. This reduces fibrous content of the meal andincreases the marketability as stock feed. About 99% of oilincreases the marketability as stock feed. About 99% of oilis stored naturally in kernels and the hulls contain notis stored naturally in kernels and the hulls contain notmore than 1% oil.more than 1% oil.

If the hulls are not removed they reduce the total yield of oilIf the hulls are not removed they reduce the total yield of oilby absorbing or retaining oil in the pressed cake. Inby absorbing or retaining oil in the pressed cake. Inaddition to this the wax and colouring matters present inaddition to this the wax and colouring matters present inthe hulls get mixed with the expressed edible oil.the hulls get mixed with the expressed edible oil. ThisThisnecessitated the refining process, and therefore, increasenecessitated the refining process, and therefore, increasethe production cost of edible oil.the production cost of edible oil.

Moreover, processing oilseeds without dehulling reduces theMoreover, processing oilseeds without dehulling reduces thecapacity of the extraction equipment in addition to morecapacity of the extraction equipment in addition to morerepair and maintenance chargesrepair and maintenance charges ..


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Approximate Hulls and Kernels Percentage in differentApproximate Hulls and Kernels Percentage in differentseedsseeds

% oil% oil % kernel % hull% kernel % hull whole kernel huskwhole kernel husk

Cottonseed 55 45 19 30 1-2Cottonseed 55 45 19 30 1-2

Rapeseed 82 18 42 - -Rapeseed 82 18 42 - -

Sunflower 75 25 22-36 36-55 1-2Sunflower 75 25 22-36 36-55 1-2

Soybean 93 7 18 19 0.6Soybean 93 7 18 19 0.6


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Bar hullerar hullerThe rotating member of a bar huller is a cylinder equipped on itsThe rotating member of a bar huller is a cylinder equipped on its

outer surface with a number of slightly projecting,outer surface with a number of slightly projecting,longitudinally placed, sharply ground, square-edged knives or longitudinally placed, sharply ground, square-edged knives or bars.Opposed to the cylinder over an area corresponding tobars.Opposed to the cylinder over an area corresponding toabout one-third of its surface is a concave member providedabout one-third of its surface is a concave member providedwith similar projecting bars.The seed are fed between thewith similar projecting bars.The seed are fed between the

rotating cylinder and the concave member, and the hulls arerotating cylinder and the concave member, and the hulls aresiplitted as the seeds are caught between the opposedsiplitted as the seeds are caught between the opposedcutting edges.The clearence between the cutting edges maycutting edges.The clearence between the cutting edges maybe adjusted for seed of different sizes.be adjusted for seed of different sizes.

seed

Bars (concave surface 1/3)

Square-edged knives


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Disc hullerisc huller

The disc huller consists of vertically mounted discs,The disc huller consists of vertically mounted discs,

one of which is stationary and the other one of which is stationary and the other rotating.The seeds are fed to the center of the discsrotating.The seeds are fed to the center of the discsand are discharged at their periphery by centrifigaland are discharged at their periphery by centrifigalforce.force.

seedsRotating disc

Stationary disc

Adjust according to seed size


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The moisture content of seed effects theThe moisture content of seed effects theefficiency of dehulling operation.efficiency of dehulling operation.

Wet seedsWet seeds

are difficult to split cleanlyare difficult to split cleanly

and may clog the huller.and may clog the huller.

If If the seeds are very drythe seeds are very dry , the kernels, the kernelsmay disintegrate excessively.may disintegrate excessively.

Universal dehullingUniversal dehulling


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Universal dehullingUniversal dehullingSeedSeed

First huller (coars huller)First huller (coars huller)

Hull beater Hull beater

KernelKernel HullHull Uncut seedUncut seed

Second huller Second huller

Hull beater Hull beater

KernelKernel HullHull UncutseedUncutseed


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FLAKINGThe extraction of oil from oil seeds,either by mechanical extraction or solvent extraction, is facilitated byreduction of the seed to small particles.

Flaking is achieved on corrugated rollstands. Cracking mills with one or twopairs of rolls are used.

Hammer mills are used for certain rawmaterials like palm kernel.


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Crushing rollsCrushing rollsA roll assembly commonly used for the reduction of oilA roll assembly commonly used for the reduction of oil

seeds consists of a series of five rolls placed oneseeds consists of a series of five rolls placed oneabove the other. The seed is introduced by a feedingabove the other. The seed is introduced by a feedingmechanism between the two top rolls.Seed travelsmechanism between the two top rolls.Seed travelsfrom the top to the bottom of the system, hence it isfrom the top to the bottom of the system, hence it isrolled four times.rolled four times.

Corrugated roll

Speed 0.05 m/sec

knife

Smooth rolls

kernel

flake


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COOKING HEAT TREATMENTCOOKING HEAT TREATMENTEffects of cooking process on the physicalEffects of cooking process on the physical

and chemical properties of oil seeds;and chemical properties of oil seeds;The oil droplets in the oil seed areThe oil droplets in the oil seed areultramicroscopic in size. Because of theultramicroscopic in size. Because of theincrease in temperature they comeincrease in temperature they cometogether and form larger droplets to flowtogether and form larger droplets to flowfrom the seed.from the seed.Heating of the seeds causes the protein toHeating of the seeds causes the protein todenature and as a consequence, thedenature and as a consequence, theemulsion to break and the oil to seperateemulsion to break and the oil to seperatefrom the solid surface of the seed.from the solid surface of the seed.


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Cooking of the seed gives the seed massCooking of the seed gives the seed massthe proper plasticity for efficientthe proper plasticity for efficientpressing.pressing.Insolubulization of phosphatides andInsolubulization of phosphatides andother impurities.other impurities.Destruction of molds and bacteria.Destruction of molds and bacteria.Increase of the fludility of the oil throughIncrease of the fludility of the oil throughincrease in temperature.increase in temperature.In the case of cottonseed, detoxificationIn the case of cottonseed, detoxificationof gossypol or related substances.of gossypol or related substances.

A four high stack cookerA four high stack cooker


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A four high stack cooker A four high stack cooker The cooking of oil seeds is usually carried out in stack cookers.TheseThe cooking of oil seeds is usually carried out in stack cookers.These

consist of a series of four to eight closed, cylindirical kettles. Eachconsist of a series of four to eight closed, cylindirical kettles. Eachkettle is normally jacketed for steam heating on the bottom and iskettle is normally jacketed for steam heating on the bottom and isequipped with a sweep-type stirrer mounted close to the bottom.Thereequipped with a sweep-type stirrer mounted close to the bottom.Thereis an automatically operated gate in the bottom of all kettles. The topis an automatically operated gate in the bottom of all kettles. The topkettle may be provided with spray jets for the addition of moisture tokettle may be provided with spray jets for the addition of moisture tothe seed, and each of the lower kettles is provided with an exhaustthe seed, and each of the lower kettles is provided with an exhaustpipe with natural or forced draft for the removal of moisture, thus it ispipe with natural or forced draft for the removal of moisture, thus it is

possible to control moisture content of the cooked seed.possible to control moisture content of the cooked seed.

Direct steam

Sweeper-type stirrer

Exhaust pipe

T (0C)

Cooked flakes

Seed flakes

gates

2-3.5 m diameter

50-70 cm high


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Cooking of cottonseedCooking of cottonseed

DetoxificationDetoxification

Before cooking, moisture 12.%Before cooking, moisture 12.%

Cooking time 90 mnCooking time 90 mn

Final cooking temperature 115Final cooking temperature 115 00CC

Final moisture 3%Final moisture 3%


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Documents

Oil and Fat Technology Lectures III