World Bank DocumentBran A milling by-product consisting of the outer layers of the kernel and part of the germ. Brewers The smallest fragments of broken rice kernels after milling;

THE WORLD BANK FAU 8

FA U-08

I.

SECTORAL LIBRARYINTERNATIONAL BANK

FORRECONSTRUC1TON AND DFVELOPMENT

FEB 121986

Agro-Industry ProfflesRICE

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PROFILES IN THIS SERIES:

OILCROPS - OVERVIEW ........... FAU-01

OIL SEEDS ................... . FAU-02

OIL PALM. . *. *.... . . .o......... .FAU-03

COCONUT. .e. .... . . . ..**** *..... FAU-04

SUGAR. .. .... .......e.o......... FAU-05

ETHANOL. . .e. .o.o................ .FAU-06

WHEAT. ..... ....... e.....e.....o. FAU-07

RICE .eee...e. .o. . . . .e.. ... .FAU-08

CORN ..oo...................o...FAU-09

CASSAVA ........................ FAU-10

ANIMAL FEEDS ...... ....... .FAU-11

FRUITS AND VEGETABLES.........FAU-12

RUBBER. ... .. . ............. e.e.. FAU-13

COFFEE .o.e..................... FAU-14

TEAo...o..e.o...eoe.ee........e.FAU-15

COCOA. .. ................e.e.ees o . FAU-16

COTTON .. o.e...................... FAU-17

MEAT. .. . . . e... . .. ...e...e . FAU-18

SPICES AND ESSENTIAL OILS ..... FAU-19

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ABSTRACT

The objective of this Profile is to provide a review of the riceprocessing industry. It provides basic data on rice productionand discusses in detail the milling system, from drying to finalscreening. It outlines the major features of rice storage andmarketing, including quality/grade factors and the uses of bothrice and its milling by-products. A bibliography of usefulreferences is provided. Annexes showing investment and operatingcosts of sample milling operations, and conversion tables areincluded at the end of the Profile.

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FOREWORD

The nature of project and sector work in the World Bank is suchthat staff are often called upon to work outside their majorfields of specialization, if only to make an initial judgement onthe utility of further, often costly, investigation. Under thesecircumstances, up-to-date and authoritative reference material isessential.

The profiles in this series are designed for use by operationalstaff with experience in the agricultural sector but who do nothave a technical knowledge of the particular commodity underdiscussion. Their purpose is not to substitute for technicalexpertise but to provide a reliable inhouse reference which willhelp Bank staff to determine when and what expertise is needed inthe detailed evaluation of investment proposals in agro-processing.

The conditions for any particular proposal are bound to be uniquein a number of respects, and the use of norms and general data inproject analyses could give rise to significant errors. On theother hand, by providing responsible staff with a guide to theissues on which appropriate expertise should be sought, theseprofiles can contribute to the overall quality of agro processinginvestment. Used with care, they should also facilitate broadpre-screening such as may occur during sector work andreconnaissance.

Questions, comments and further inquiries should be addressed to:

Agro-Industries AdviserFinance and Agro Industry UnitAgriculture and Rural Development Department

The contribution of Ibberson International, Inc. in the review ofthis profile is gratefully acknowledged.

September 1985

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Rice

CONTENTS

DATA SHEET .

INTRODUCTION .1

GLOSSARY .1

RAW MATERIALS .4

MILLING .6

MARKETING ASPECTS. 13

OTHER FACTORS .16

0BIBLIOGRAPHY ... 19

ANNEX I EXAMPLES OF INVESTMENT AND OPERATING COSTS

ANNEX II CONVERSION TABLES (METRIC/US)

ANNEX III RICE CONVERSION FACTORS

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Rice

DATA SHEET

Grain Characteristics: Dimensions and shape (of grain, brownrice, or milled rice). Measurements given: length, width, andthickness in millimeters. Shape can be expressed by the length-width ratio.

FAO scale USDA IRTP-IRRIfor worker's scale scale

milled rice for brown rice for brown rice

Length class (80% of - - - - - - - mm - - - - - - - - - -sample or more)

Extra long 7.0 and over over 7.5Long 6.0-6.99 6.6-7.5 6.61-7.50Medium 5.0-5.99 5.5-6.6 5.51-6.60Short less than 5.0 less than 5.5 less than 5.51

Shape class (80% of - - - - - length/width ratio - - - - -sample or more)

Slender (long) over 3.0 over 3.0 over 3.0Medium -- 2.1-3.0 2.1-3.0Bold 2.0-3.0 less than 2.1 1.1-2.0Round (short) less than 2.0 -- less than 1.1

Table 1: Grain characteristics of rice(Source: IRRI)

Pound and Kilogram equivalents of international units of measureare listed in Table 2 on the following page.

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Table 2: Rice -- Units of Measure-----------------------------------------------------------

Measure Product Weight per UnitPoundrs - Kilograms

BUSHELAustralia paddy 42 19.05Brazil paddy 45 20.41Cambodia milled 46 20.86Sierra Leone paddy 60 27.21

milled 84 38.10Sri Lanka paddy 46 20.86United States paddy 45 20.41

BAG OR SACKBrazil paddy 110.23 50.00milled 88.18 40.00Burma milled 225 102.6Egypt milled 220.11 99.84Gnana milled 240 108.86Guyana paddy 140 63.50

milled 180 81.65Malawi paddy 150 68.04milled 200 90.72Surinam paddy 154.32 70milled 220.46 100United States (cwt) paddy 100 45.36milled 100 45.36

OTHER MEASURESBurma : Basket paddy 46 20.86Basket milled 75 34.02China PR : Catty 1.1 0.5Colombia : Arroba 27.6 12.50Egypt : Darriba paddy 2083.37 945Korea : Suk paddy 220.5 100

milled 317.5 144husked 330.7 150India : Maund 1/ 82.28 37.4Japan : Koku husked 330.69 150Malaysia : Picul 2/ 133.33 60.48Gantang 5.60 2.54Mexico : Carga paddy 304.24 138milled 352.74 160Panama : Lata paddy 24.99 11.33milled 35.99 16.32Philippines : Cavan paddy 97.00 44milled 123.46 56*Sri Lanka : Measure milled 2 0.91Swaziland : Pocket 100 45.36Thailand : Kwien paddy 2226.67 1010Picul 3/ milled 132.28 60Kwien husked 2910.11 1320Uruquay : Bolsa 110.23 50United states : Barrel paddy 162 73.48

-1/ Also Pakistan2/ Also Brunei, Honq Kong, Macau, Sarawak, Singapore3/ Also Cambodia and Laos

Source: FAO Rice report 1974/75; Reprinted in World Bank, 1981

INTRODUCTION

Rice is the staple food for about half of the world's population.It is grown on all continents, under a range of climaticconditions. Yields under irrigated conditions range from anaverage of about two tons/ha in developing countries to fivetons/ha in Japan and the United States.

Milling is the term applied to the collective operations of arice processing plant, or, to the specific operation involvingseparation of the outer bran from the rice. The former includesremoval of foreign matter, outer hulls, bran, and germ, followedby polishing and glazing to add to consumer appeal.

The vast majority of the world's production of rice is consumedin kernel form, making further processing unnecessary.

A current, detailed coverage of rice milling techniques isprovided in Technical Handbook for the Paddy Rice Post-HarvestIndustry in Developing Countries by J.E. Wimberly (1983).

GLOSSARY

Bran A milling by-product consisting of the outerlayers of the kernel and part of the germ.

Brewers The smallest fragments of broken rice kernelsafter milling; used in brewing.

Brown bran Bran obtained from the milling of parboiledrice.

Brown rice Rice from which hulls have been removed.(Cargo Rice)

Dwarf rice Rice plants characterized by their relativelyshort stalks, resistance to lodging, and* adaptability to mechanical harvesting.

Early variety Fast maturing rice, requiring 100-140 daysfrom seeding to maturity.

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Extracted rice Residue remaining after the extraction ofbran rice pollards.

Fortified rice Milled rice which has been treated to improve(Enriched rice) its nutritive value.

Glazed rice Milled rice which has been coated with a(Coated rice) talc and glucose mixture to enhance shine.

Glutinous rice Rice with a chalky, opaque endosperm, which(Waxy rice) is stickier when cooked.

Head yield Post-milling yield of unbroken kernels andthose of 3/4 length or more.

High yielding Systematically developed rice varietiesvarieties (HYVs) known for their superior yields. May also

have improved disease resistance andtolerance to climatic variation.

Hull The thick outer covering of paddy, alsoknown as husk.

IRRI International Rice Research Institute,located in the Philippines.

Late maturing Varieties which require 155 days or morevarieties from seeding to maturity.

Lowland rice Rice grown in a flood culture during mostor all of its growing period.

Milled rice Rice from which the husk and most of the(white rice) bran layers have been removed.

Midseason Rice requiring 140-155 days from seeding tovarieties maturity.

Paddy Refers to either the entire growing plant or(rough rice) the threshed grains with their hulls intact.

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Parboiling An optional pre-milling treatment of soaking,steaming, and drying which gelantinizes thestarch, and increases the nutritive value ofthe rice, as water-soluble vitamins andminerals from the bran penetrate theendosperm.

'Pecky' rice Milled rice containing distinctly discoloredkernels, which lower the quality.

Polished rice Milled rice which is scoured to remove theinnermost bran layer and is polished in theprocess.

Quick-cooking Cooked, dehydrated rice that can be reconsti-rice tuted in 5 minutes with the addition of boil-

ing water.

Rice mill feed A mixture of rice pollards and ground ricehulls, used for animal feed.

Rice pollards A mixture of rice bran and rice polishings,comparable to wheat when used as a high-energy, high-protein feed.

Rice polishings The inner layers of bran, part of the germ,and a small amount of the starchy interior,removed during polishing; also known as ricemeal, rice flour.

Screenings Medium-sized fragments of broken rice kernelsfollowing milling.

Second head The largest fragments of broken rice kernelsfollowing milling.

Stalk paddy Rice plants which have been cut, but notthreshed.

Upland rice Rice produced under rainfed conditions.

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RAW MATERIALS

Most cultivated rice is of the species oryza sativa. It is ashallow-rooted annual grass, with stems growing from 2-6 feet ormore in height. Rice is commonly self-pollinating, and, unlikeother cereals, it is able to germinate when submerged in water.

The mature rice seed is composed of a seed coat, embryo, andendosperm. The rice grain is normally light brown in color, buthas been known to range from red and purple to golden and grey.It varies with respect to translucency, presence or absence ofchalky spots, and hardness.

Two types of rice are dominant. Indica is predominately grown inSouth and Southeast Asia and China. While it is well-suited toareas of low soil fertility, uncertain weather conditions, poorwater control, and is resistant to many pests, it is notwell-adapted to modern farming techniques (Considine, 1982).

Japonica, on the other hand, grows well in temperate zoneconditions in, for example, Korea, Japan, Europe, and parts ofthe United States and Australia. It is characterized by ashorter, stiffer stalk; a shorter growing period; and resistanceto lodging, hence it is well-suited to modern agriculturalmethods (Ibid).

The growing season for rice is normally four to six months; theaverage temperature during this period should be no lower than 70F (21.1 C) (Ibid). While the optimal soil pH is 6.5 for ricecultivation, more rice-growing soils worldwide tend to be acidic,with a pH ranging from 4-6 (Ibid).

Cultivation methods are broadly classified as Upland and Lowland.

Upland rice is that which is grown under rainfed conditions whenflooding is not possible. High humidity and substantial rainfall(at least 40 inches per year) are required. Direct seeding,mechanical harvesting, and relatively lower yields (usually 1/3to 1/2 those of Lowland) are frequently associated with this typeof cultivation (Ibid). Yield is largely determined by amount anddistribution of rainfall during the growing season.

Lowland rice is that which is grown in submerged fields for agood part, if not all, of its growing period. Water depth rangesfrom 5-15cm (shallow) to more than one meter (deep-water).

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Lowland rice cultivation usually involves the transplanting ofnursery-grown seedlings by hand. The surface water must bedrained for application of fertilizers and pesticides (Ibid). Inthe U.S., rice is direct-seeded to obtain stands of 15 to 20plants per square foot. Fields are flooded when the plants aresix to ten inches high and drained about two weeks prior toharvest.

Presently there are over 8,000 types of rice, including a largenumber of high yielding varieties (HYVs) (Ibid). The latter,when combined with fertilizers, controlled water, and pesticides,contribute significantly to increased rice yields.

Rice is ready for harvest when about 80% of the plant is straw-colored, i.e., when the lower kernels are in the hard-dough stage(DeDatta, 1981). When harvested too early, there is a highproportion of weak, immature, and chalky grains which have atendency to break during milling. When harvested too late, fieldlosses are greater, as is the percentage of stress-cracked grainswhich are also more likely to break during milling.

Harvesting can be done mechanically or manually. When a combineis used, the stalk is severed just below the grain so as tominimize the passage of straw through the thresher. In hand-harvesting, the straw is cut with a sickle 15-25 cm above theground.

Threshing, or removal of the grain by impact from the harvestedplant, is accomplished manually, by beating the panicles on aslotted platform, by animals which tread on the harvested crops,or by machines which range in size from a small, portablethresher (such as that designed by the International RiceResearch Institute - IRRI) to a large thresher with an outputcapacity which exceeds 1.5 tons/hr. Threshing losses, i.e.,grain which remains on the panicle following threshing, rangefrom 8% for a large stationary machine to 7% for manual threshingto less than 2% for the IRRI-designed portable threshers(DeDatta, 1981)

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MILLING

Milling methods range from traditional pounding with mortar andpestle, to the use of fully-mechanized, large-scale processingplants. The only processing required prior to consumption isremoval of the hull, germ, and bran. Since most rice is consumedin grain form, it is important to minimize breakage. Brokengrains detract from cosumer appeal and are more susceptible toinfestation, and the percentage of broken grains is a majordeterminant of grade and price.

Rice milling involves the collective operations of drying,cleaning, shelling, separation of kernels, bran removal,brushing, trumbling, and final screening, as illustrated in theflowchart below.

Riec tlour A IgC$ tiour

Tlc/G Ucole Polistie rice

R ecycit Undermlad

f; _s * _~~~~~~~~~~~~SeaaTn

Drown r Pce n

l I

Flowchart 1: Rice MillingSource: Considine (1982)

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Drying

Harvested paddy normally contains 18-25% moisture. In order toavoid deterioration, drying must begin no more than 24 hoursafter harvesting (DeDatta, 1981). For short-term storage (two tothree months), the moisture content should be reduced to 13-14%;for long-term storage (more than three months), it should notexceed 12-12.5% (Wimberly, 1983).

In many parts of the world paddy is either left in the fieldprior to threshing or spread on waterproof threshing floors todry in the sun. This is a labor-intensive method requiringconstant turning. Losses from sun-drying are relatively high dueto (1) exposure to the vagaries of weather over the four-to-fiveday period required for proper drying; (2) consumption by insectsand rodents; and (3) stress produced in the grain as a result ofuneven drying and changes in temperature from day to night.

Mechanical driers are of three basic types: Batch-in-bin,recirculating batch, and continuous flow. Typicalspecifications, performance, and estimated costs of each aredetailed in Table 3 below.

Batch-in-bin' Pczltr Batch Contin-xs FlawSmall lare Smail Iarme Small LargeDrywSeifica1i

Cacity (t) 2 100 5 10 5-10 10-25Aprmdnate hp 3 10 15 25 15-20 25-50Aoprt,x. airflcw (m3/nin per t) 50 23 56-85 70-100 85-L15 115-140Approx. drying air terp. (C) 43 43 60-80 60-80 60-80 60-80Ap= burrer capacity (Bbtl.) 100,000 4.0 M a/ 2.0 M 4.0 M 4.0 M 8.0 M

Estimatid PerrfclDying city (t/day) 6 10 15 30 60 100fran 20% to 14 % M b/Anrnal dryirg city (t) 240 400 600 1,200 2,400 4,000

(40 days/year cDraticn)

Estifte Oot C/ (US;$)Irves t dryirrjegaipTet 800 6,000 15,000 24,000 40,000 50,000Anral fixed cst 240 1,800 4,500 7,200 12,000 15,000Arial variable cat 720 1,200 1,800 3,600 7,200 12,000Arnual total ct 960 3,000 6,300 10,800 19,200 27,000* Ct/t 4.00 7.50 10.50 9.00 8.00 6.75

a' Wl,000,000 b/ Moisture Catent c/ Basd on 1978 Price Data

Table 3: Dryer Specifications, Performance, and Cost for DryingRaw Paddy from 20% to 14% Moisture.

Source: Wimberly (1983)

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In a batch-in-bin dryer, paddy is spread to a depth of 0.6-3.0meters over a perforated floor. Heated air is forced into thecompartment, to be released following passage through the paddy.(Relative humidity of the forced air should be below 60%.) Thegrain is stirred regularly to ensure more even drying.

A recirculating batch dryer forces hot air through a batch of wetpaddy as it falls from the top of the unit. It is then liftedback up to the top and the process is repeated until drying iscomplete.

Continuous flow dryers are used in conjunction with conveyingequipment, by means of which the paddy input is regulated. Wetpaddy is introduced into the top of the unit in a thin layer (nomore than 10-25 cm thick). Large volumes of heated air areforced through this layer as it descends through a large verticalcolumn. Continuous-flow driers are often combined with temperingbins, since tempering between drying passes serves to equalizethe uneven moisture content.

Drying should be slow and uniform to avoid grain stress, whichleads to breakage during milling. For this reason, hightemperatures should be avoided.

Cleaning

Paddy often contains quantities of straw, soil particles, weed,seeds, small stones, and other debris which must be removed priorto milling. Cleaning serves to reduce drying and storagerequirements and costs, and to remove matter which could reducethe grade of the rice, damage the milling equipment, or lead tothe deterioration of the paddy.

Scalping is a pre-drying operation, in which large foreign matteris removed by screening, and dust and light-weight matter areremoved by aspiration. Scalper cleaner (or scalperator)capacities range from two-six tons/hour to 20-50 tons/hour(Wimberly, 1981).

A second cleaning takes place as the first step in the millingoperation to remove remaining impurities. This employs the useof sieves, aspirators, magnetic separators, and sometimesde-stoners. Capacity is usually geared to rice mill capacity,and ranges from one-four tons/hour.

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Shelling (De-husking)

Traditionally the hull was removed manually, by hand-pounding thepaddy. The principal disadvantages of this method are therelatively low yields (about 50%) and low throughput (50 kg ofpaddy/person/day) (Esmay, et al, 1979). Except in remotesubsistance communities hand-pounding has been replaced by steelhullers, disk shellers, or rubber rollers.

Steel hullers remove both hull and bran by means of a shearingaction resulting from the rotation of the rollers. Bran andground hulls then pass through a fine screen. While thesemachines are relatively simple to manufacture, operate, andmaintain. Milling efficiency is low (total yield is about 46-47%head rice and 17% brokens), as is throughput (100-500 kgoutput/hr), and power requirements are high (Ibid).

Disk shellers consist of two abrasive-surfaced disks, one ofwhich rotates while the other remains stationary, dehulling paddyplaced between the two upon contact. Hulls are later removed byaspiration. Disk sheller capacity ranges from 500-5000kg of* paddy/day (Ibid). The advantages of this system lie in its easeof maintenance and repair, higher milling efficiency (up to 56%head, 11-12% brokens), and adaptability for large-scalecommercial processing (Ibid).

Rubber rollers are used in most modern rice mills. Paddy ispassed through a number of pairs of rubber rolls which revolve atdifferent speeds. One roller tends to hold the kernel while theother pulls at the hull. The distance between rollers isregulated according to grain size. Although initial capitalcosts are high, so, too, is milling efficiency: head rice yieldis up to 62% while total hulled rice recovery can be about 70%(Ibid). Aside from the high investment cost involved, theprincipal disadvantage of the rubber roller is that rollersurfaces wear out quickly and must be replaced frequently.

Milling efficiencies of different methods, with uniform properlydried paddy, are compared in Table 4 on the next page.

Following de-hulling, the grain passes through a paddy machine,which culls out unhulled kernels. These are then recycled to thesheller, while brown rice (de-hulled paddy) goes on to the mill.

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Table 4: Rice Milling EfficiencySource: Esmay, et al (1979).

Tbtal Husk Total HaHusk Bran ard Bran Head Bken and BrknMillinProcesgs (% f% 1% (% M% (%)

Harl prdin - - 40 40 20 60Steel Hullers - - 36.6 46.5 16.9 63.4Disk sellers - - 32.5 55.9 11.6 67.5RlSber rollers 22 8 30 62 8.0 70.0

Bran Removal (Milling)

Milling removes the outer bran coat of the brown rice. Thedegree of milling affects the nutritional value of the finalproduct. While well-milled, whiter rice is preferred by mostconsumers, less-milled rice actually contains more protein,vitamins, and minerals. Disadvantages of less-milled riceinclude increased cooking time required, chewier texture, a lowermarket price for processors, and reduced storage life. (Brownrice tends to become rancid after about two months, due to theoil content of the bran.)

Bran is removed by friction or by abrasion. Abrasive-type mills(also referred to as 'pearlers' or 'whiteners') such as thevertical cone mill and the horizontal abrasive mill, remove theouter bran layers as the rice kernels come into contact with amoving abrasive surface. Calcium carbonate may be added as anagent to facilitate the process. Generally there are two, three,or four mills in a series.

In friction-type mills, the bran is removed as kernels rubagainst one another under slight pressure conditions. One or twocycles of milling is sufficient to produce well-milled rice.

Solvent extraction milling (SEM) is a relatively new method inwhich bran layers are chemically softened with a spray of warmrice oil and then milled in the presence of an oil solvent. Themilled rice is screened, rinsed, and dried. The solvent is thenremoved in a two-stage process. The advantages of this processare fivefold (Kent, 1983):

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(1) The head rice yield is about 10% higher.(2) The rice produced is almost fat-free, and can, as a result,

be stored for longer periods.(3) The bran by-product has a much higher protein content.(4) The stability of the bran is higher.(5) About two kg of rice oil is obtainqd from each 100 kg of

brown rice milled.

Brushing/Polishing

Brushing or polishing removes the innermost bran coat (known aspolish) by means of mild abrasion. One type of brushing machineis similar in principle to a vertical cone mill. Instead of anabrasive cone, however, leather strips are used. The milled riceis rolled under mild pressure between the leather and a filteringscreen. The result is polished rice. Polishing lowers the riskof developing oxidative rancidity, thereby extending the storagelife of the rice.

O Trumbling/Coating

Trumbling is the coating of polished rice with a mixture of talc(magnesium silicate) and syrup sugar in order to increase riceshine. Rotation of a trumble evenly distributes the talc/glucosemixture over the rice. The possibility of a causal relationshipbetween asbestos-contaminated talc and stomach cancer in Japanhas resulted in reduced talc usage (Kent, 1981). Possiblesubstitutes include calcium phosphate, calcium acetate, calciumlactate, and calcium citrate.

Sizing

The finished product must be separated according to kernel size.Preliminary sizing is accomplished with the use of screens.Final sizing, where more precision is demanded, requires the useof screens or cylinders, the inside of which is covered withthousands of small indentations or pockets, each large enough tohold a single grain of rice. Both long and short kernels are. picked up in the pockets and, as the wall of the cylinderapproaches a vertical position, the longer kernels, which extendover the edge of the pocket, fall out.

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Milled rice is classified by length as long, medium, and short,and by shape (length/width) as slender, medium, bold, and round.Specifications for each are presented in Table 1, in the Data-Sheet.

Parboiling

Parboiling is an optional process which involves soaking orsteeping paddy in unheated water, heat treatment (steaming orboiling), and drying prior to milling. This results in anincrease in the nutritive value of the grain, since water-solubleminerals and vitamins in the bran are introduced into theendosperm of the kernel. Other advantages include (Considine,1982): (1) strengthening of the grain and reduction of breakagein milling; (2) improved cooking quality, i.e., parboiled rice.isless sticky; (3) improved storing qualities; (4) loosening ofhulls, which facilitates de-hulling; and (5) more resistance toinsect attack. Parboiled rice normally commands a premium in themarket.

Disadvantages include (Wimberly, 1983; Kent, 1983): (1) longercooking time requirements; (2) higher total costs of processing;(3) the possibility of discoloration or deterioration in flavor;(4) increased difficulty and cost in bran removal; (5) greatercapital investment requirement; and (6) an increased tendency tobecome rancid. Steeping in a sodium chromate solution (0.05%)will minimize flavor change; steeping in a metabisulphitesolution (0.3%) will bleach the rice.

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MARKETING ASPECTS

Quality/Grade

Milling quality; cooking, taste and further processing quality;nutritive quality; and specific measures of cleanliness andpurity comprise the four broad categories of rice quality. (Luh,1980). Specific quality determinants include (Ibid):

(1) Type, which is classified according to grain length, shape,weight and uniformity.

(2) Moisture, which affects keeping quality, milling yield, andcooking and processing qualities.

(3) Chalkiness, which is an indicator of grain weakness (leadingto breakage in milling) and detracts from appearance.

(4) Milling yields, as measured primarily by percentage yield ofhead rice.

* (5) Degree of milling, which indicates the extent to which branlayers have been removed.

(6) Color, which varies from greyish to reddish for milled riceand from light to dark for parboiled rice. Rice is gradedvisually.

(7) Dockage, or impurities which can be readily removed bycleaning.

(8) Damaged kernels, which have been discolored or otherwisedamaged by water, insects, or heat.

(9) Red rice, which contains large amounts of red kernels or redbran.

(10) Odors, e.g., musty, sour, earthy, rancid, or any otherconsidered to be objectionable.

(11) Seeds, or grains from any other kind of plant.

* Grades and prices of milled rice are also dependent on brokenkernel content, with classifications ranging from 5% to 45%brokens in intervals of 5-10% in Thai rice, for example.

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Uses

The vast majority of rice is consumed in grain form, either asbrown, milled, parboiled, enriched, quick-cooking or puffed rice.Enriched rice is that which has been fortified with additionalvitamins or minerals to compensate for those lost during milling.Enrichment with B-vitamins is common when rice comprises theprincipal component of the diet, since a vitamin-B deficiency canlead to beri-beri.

Quick-cooking rice takes between one and five minutes to cook, asopposed to 20-30 minutes for milled rice. It is produced by acombination of soaking, pressure-cooking, and air-drying undercontrolled conditions.

Puffed rice is used as a base for breakfast cereals and sweets.Its manufacture involves the injection of steam into the grainunder pressure, expansion of the steam to puff the rice, anddrying of the resultant kernel. A puffed kernel is usually 10times the size of a normal kernel.

By-Products

Rice brokens, bran, hulls, and straw are the by-products of ricemilling.

Brokens are used in flour, starch, and alcoholic beverageproduction. Rice flours can be parboiled or non-parboiled, andenriched or unenriched. Most are ground from second-head rice.Since rice flours contain no gluten they are generally not usedfor bread-baking, except in mixtures with other grain flours.Flour produced from glutinous rice is used in the preparation ofprocessed foods. It is especially well-suited as a thickener insauces, gravies, and puddings, for example, because it reducesseparation following freezing and thawing.

Starch produced from over-boiled rice is used by laundries and infoods, cosmetics, and textile manufacturing.

Fermented rice is used in the production of alcoholic beverages,such as saki in Japan and wang-tsiu in China. It is also used inbrewing because of its good flavor and aroma, and its tendency toextend beer shelf life. In the U.S., for example, 25% of allrice consumed goes to breweries (Grist, 1975).

Rice bran contains 10-13% protein in addition to a range of

14

vitamins and minerals (Ibid). It is generally used as ahigh-nutrition animal feed. Oil can be extracted from the branand refined. It is then used in cooking, in the production ofshortening and margarine, and for industrial purposes.

Hulls are undigestible because of their high silicon content(Ibid). They can be used as fuel for milling operations(according to Grist [1975] they can supply the mill's entireenergy needs). They are also used as stable and poultry litter,fertilizer, a medium for hydroponic cultivation of vegetables,and in making building materials, paper, abrasives, soaps andresins. (Note: 'Rice paper' is not related to the rice grainnor its by-products.)

Rice straw can be used in a mix for cattle feed, as mulch for amushroom culture, in woven craft products, and in the manufactureof building materials.

Substitutes

Most cereals are processed and used as an ingredient in thepreparation of another product, e.g., bread or pasta. For thisreason there is some degree of substitutability among grains.This generally does not hold for rice, however, since most riceis consumed in grain form.

Grist (1975) reports that other grains now compete with rice indifferent areas of the world, e.g., wheat in parts of China,India, and Pakistan; maize in Cambodia, Indonesia, and thePhilippines; beans, maize, and starchy roots in Latin America;and millet, sorghum, and roots in West Africa. These shifts arenormally a cultural reaction to changing incomes.

Where rice is the preferred grain, increases in income result inan increase in rice consumption until a 'saturation level' isreached. Beyond this level livestock products and other morecostly food items increasingly displace the share of rice in thediet. The saturation level is being reached in countries such asBurma and Thailand, and has been passed in Japan, where annualper capita consumption has fallen from a 1920 high of 140 kg tothe present (1978) level of 86 kg (World Bank, 1981).

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Market Structure

International trade in rice is small compared to that of manyother grains since most of the world's large-scale producersconsume the majority of their domestic production. According tothe World Bank (1981), 96% of world production is consumeddomestically. Long and medium grains comprise 85% of the totaltraded volume. Rice is generally traded in milled and bag form.

The market structure for rice is characterized by (1) a highproportion of concessionary or subsidized transfers; and (2) ahigh proportion of sales by government contract (Ibid). Theportion of trade conducted through commercial channels is, as aresult, relatively small, and open market rice prices areconsequently unstable. This situation is exacerbated by weatherconditions (especially monsoons) in Asia, where 90% of theworld's rice is grown.

Barriers to Market Entry

Barriers to market entry are numerous; domestic markets areheavily protected due to the importance of rice in the foodsecurity position of many countries. Accumulation of bufferstocks is common to help insure adequate domestic supplies.

The role of the Generalized System of Preferences in rice tradeis limited.

OTHER FACTORS

Location

The overriding concern in the determination of a rice mill siteis the immediate availability of paddy. Mills in close proximityto paddy supplies will minimize transportation costs as well aslosses due to delays between harvest and drying (deteriorationbegins within 24 hours of harvest).

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Storage

Storage capacity requirements are determined to a large extentby: (1) the number of rice crops harvested per year; (2) howthese crops and their harvest are staggered; and (3) therelationship between quantity and timing of consumption versusthat of harvest. (Wimberley, 1983)

To maintain paddy quality during storage it is important that itbe clean and have moisture content of 14% or less. 12% or lessis ideal since that level of grain moisture equates to 70%relative humidity in the air surrounding the grain, below whichmould formation will not occur during long-term storage. Safeshort-term storage life of paddy at higher moisture levels ispresented in Table 5.

once stored, grain must be protected against (Ibid):

(1) Rodents and birds, which not only can consume large amountsof grain, but can also contaminate it with disease-transmitting droppings and urine.

(2) 'Insects, which can contaminate the grain and cause itstemperature and moisture levels to rise. Basic sanitationmeasures combined with chemical sprays or fumigants areeffective in controlling insect damage.

(3) Microorganisms (fungi and bacteria), which can causesubstantial losses through discoloration, and development oftoxins, mustiness, weight loss, and disagreeable odors andflavors. Microorganism growth is a frequent problem in highhumidity, high temperature tropical environments.

Aeration systems which move fresh air through the stored paddyare recommended to (1) cool the grain; (2) minimize odordevelopment; (3) reduce moisture; and (4) introduce fumigants.Common airflow rates range from 0.07 to 0.28 cubicmeters/minute/ton (Ibid).

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Table 5: Safe Storage Life of Paddy at Different MoistureLevels and at Different Grain Temperatures.

Source: Wimberly (1983)

Grain Safe storage life (days) at indicatedTemperature moisture content(degrees C) 14% 15.5% 17% 18.5% 20% 21.5%

38 8 4 2 1 032 16 8 4 2 1 027 32 16 8 4 2 121 64 32 16 8 4 2

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BIBLIOGRAPHY

01.. Araullo, E.V., D.B. de Padua, M. Graham (1976) Rice:Post Harvest Technoloqy.Ottawa: International Development Research Centre.

02. Baron, C.G. (Editor) (1980) Technology, Employment, andBasic Needs in Food Processingq in Developing Countries.Oxford: Pergamon Press.

03. Christensen, C.M. (1982, Third Edition) Storade of CerealGrains and their Products.St. Paul: American Association of Cereal Chemists, Inc.

.04. Clarke, P.A. (1978) Rice Processing: A Check List of Com-mercially Available Machinery.London: Tropical Products Institute.

05. Considine, D.M. (Editor) (1982) Foods and Food ProductionEncyclopedia.New York: Van Nostrand Reinhold Co.

06. DeDatta, S.K. (1981) Principles and Practices of RiceProduction.New York: John Wiley and Sons.

07. Desikachar, H.S.R. (1980) Three Decades of Research on theProcessing and Utilization of Foodgrains.Journal of Food Science and Technology, 17 (1-2):24-32.

08. Esmay, M. Soemangat, Eriyatno, and A. Phillips (1979) RicePostproduction TechnoloQy in the Tropics.Honolulu: University Press of Hawaii.

09. FAO (1971) Report on the Meeting of Experts on the Mech-anization of Rice Production and Processina.Rome: FAO.

10. Flynn, G. and P.A. Clarke (1980) An Industrial Profile ofRice Milling.London: Tropical Products Institute.

11. Grist, D.H. (1975, 5th Edition) Rice.Essex: Longman Group, Ltd.

19

12. Kent, N.L. (1983, 3rd Edition) Technoloav of Cereals: AnIntroduction for Students of Food Science and Agriculture.Oxford: Pergamon Press.

13. Korthals Altes, F.W. (1982) Appropriate Technology forProcessing Agricultural Products in Developing Countries,IN Appropriate Technology for Developin' Countries, W.Riedijk, Editor.Delft: Delft University Press.

14. Luh, B.S. (1980) Rice: Production and Utilization.Westport: Avi Publishing Co., Inc.

15. Osifo, D.E. (1971) Economics of the Rice Industries ofthe Western State of Nigeria.IBADAN (Nigeria): Nigerian Institute of Social and EconomicResearch.

16. Pyke, M. (1981, 4th Edition) Food Science and TechnoloQy.London: John Murray (Publishers) Ltd.

17. UNIDO (1979) Appropriate Industrial TechnoloQy for FoodStorage and Processing.New York: UN.

18. University of the Philippines, College of Agriculture (1970Revised Edition) Rice Production Manual.Laguna: University of the Philippines.

19. USDA, Economics, Statistics, and Cooperatives Service (1979)Conversion Factors and Weights and Measures forAgricultural Commodities and their Products.Washington: USDA.

20. van Ruiten, H. and H.P. Rozeboom, with the FAO (1980) Post-Production Rice Technologies in the WARDA Region.Monrovia: WARDA.

21. Wimberly, J.E. (1983) Technical Handbook for the Paddy RicePost-Harvest Industry in Developing Countries.Manila: IRRI.

22. World Bank, Commodities and Export Projection Division(1981) Rice Handbook.Washington: World Bank.

20

23. World Bank, South Asia Projects Dept., Agro-Industries andCredit Division (1984) Staff Appraisal Report on Burma:

* Grain Storage and Processing Project.Washington: World Bank.

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ANNEX I:

EXAMPLES OF INVESTMENTS AND OPERATING COSTS

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RICE MILLINGEXAMPLE 1

Page 1 of 2

Representative Investment and Operating Costs---------------------------------------------

RICE MILL

Establishment of a one ton/hour rice milling unit to produce highhigh grade rice (10% broken or less).

COUNTRY: Uganda (Busembatya Millers Ltd.)

NOTE: These data are intended as indicative only and are uniqueto the time, circumstance, and country of the identifiedinvestment. Their applicability to other situations mayvary considerably.

Annual Full Development Production:-----------------------------------

fine rice 1,048.5 metric tonsbroken rice 116.5 metric tons

Capacity Utilization at Full Development: 80.00%

--------US$ '000-------end 1983 prices

Local Foreign TotalI. Investment Costs:____________________

Land and Buildings 8.33 8.33Machinery & Equipment 0.00

(cleaner, husker, whitening 71.33 71.33machine, etc., and 0.00

including transport to site).Installation 0.67 3.77 4.43Import Duties 0.47 0.47Pre-Operating Expenses 17.87 17.87

Total Investment Costs 27.33 75.10 102.43

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Page 2 of 2



US$ '000end 1983 prices

Total Cost

II. Full Development Annual Operating Costs:--------------------------------------------

Variable Costsraw materials

597.33packing materials 21.50utilities 2.83production labor 5.20Sub-Total Variable Costs 626.87

Fixed Costsoverhead labor 6.37depreciation

19.77maintenance 0.83administration 3.03Total Fixed Costs 30.00

Total Operating Costs 656.87

DATA SOURCE: Adapted from World Bank OPEC loan 301P-UG, projectfile for Sub-Project OP-16, Uganda Development Bankappraisal report for the Busembatya Millers Ltd.

NOTES:Exchange rate - Ugandan Shillings 300 = US$ 1.00.Full development is achieved in fourth year after project start-up.Details on local/foreign exchange operating cost breakdown are notpresented in the appraisal report.Data are net of contingencies.


Page 1 of 2

Representative Investment and Operating Costs…--------------------------------------------

RICE MILLING____________

Establishment of a 2 ton/hour rice mill

COUNTRY: Lao PDR (Sanakham Mill, Vientiane Province)


Annual Full Capacity Production:________________________________

milled rice 4800 tons

Capacity Utilization at Full Development: not available

--------US$ 000-------end 1979 prices

Local Foreign Total

I. Investment Costs:____________________

Civil Workssite preparation 1.00 2.00 3.00rice mill building 450 m2 34.00 24.00 58.00paddy operational storage 675 m2 70.00 38.00 108.00rice storage 675 m2 70.00 38.00 108.00miscellaneous 2.00 3.00 5.00

Sub-Total Civil Works 177.00 105.00 282.00Machinery & Equipment

compact type 2 ton/hr mill 200.00 200.00laboratory equipment 5.00 5.00workshop equipment 5.00 5.00water supply equipment 3.00 3.00fork lift 16.00 16.00diesel engine (60 hp) 5.00 20.00 25.00spare parts 40.00 40.00

Sub-Total Machinery & Equipment 5.00 289.00 294.00Installation Charges 5.00 14.00 19.00


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Page 2 of 2



-------- US$ O00-------end 1979 prices

Local Foreign Total

II. Full DevelopmentAnnual Operating Costs(excluding raw materials)

_____________________________

Variable Costsproduction labor 5.04 5.04diesel fuel 5.53 5.53lubricants 0.55 0.55Sub-Total Variable Costs 5.04 6.08 11.12

Fixed Costsoverhead labor 3.40 3.40maintenance 0.80 0.80Sub-Total Fixed Costs 4.20 4.20

Total Operating Costs 9.24 6.08 15.32

DATA SOURCE: Adapted from World Bank project appraisal report No.2842-LA, Lao PDR Agricultural Rehabilitation andDevelopment Project III, Vol. II, Project File,Annex 2.

NOTES:All costs expressed in US $.Details on actual amounts of paddy (raw materials) procured notreadily available.Milling extraction rate is assumed at 67%.Full development is assumed to be second year after installationof mill.Data are net of contingencies.

0 RICE HlILLINGEXAMIPLE 3

Page 1 of 3

Representative Investment and Operating Costs

RICE H4ILL

Establishment of a 150 ton per day capacity rice mill.

COUNTTRY: Burma

NOTE: These data are intended as indicative only, and are uniqueto the time, circumstance, and country of the identifiedinvestment. Their applicability to other situationsmay vary considerably.

Annual Full Development Production(tons):

paddy 33000.00

Capacity utilization at Full Development: not available

--------US$ '000-------mid-1984 prices

Local Foreign TotalI. Investment Costs:

Site Developmentaccess roads 52.83 52.83fencing 43.99 11.00 54.99drainage & sewerage 12.89 12.89other 57.07 57.07

Sub-Tctal Site development 166.78 11.00 177.78Rice Godowns

foundation 47.30 47.30structural steelwork 77.88 69.07 146.95roofing and walling 32.46 28.79 61.25

Sub-Total Rice Godowns 157.65 97.86 255.51Hill Foundation 78.48 78.48Mill Superstructure

structural steelwork 91.99 81.57 173.56roofing and walling 74.89 66.41 141.30.

Sub-Total Mill Superstructure 166.87 147.98 314.85Mill Utilities 1.43 4.29

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RICE 1ILLINGEXAIMPLE 3

Page 2 of 3



-------- US$ 000-------mid-1984 prices

Local Foreign Total

Milling Equipmentlntake, cleaning, weighing 46.54 98.89 145.43husking, paddy separation 142.39 302.58 444.98whitening 111.73 237.42 349.15pre-sieving/polishing 48.86 103.83 152.70post sieving/grading 57.80 122.82 180.61grading, mixing, sacking 57.42 122.02 179.45husk refining 12.13 25.78 37.91electrical 53.10 112.84 165.94feed piping 7.06 15.01 22.07other/spare parts 73.75 156.72 230.47

Sub-Total Equipment 610.79 1297.93 1908.72Installation 307.62 307.62 615.25Transport, Insurance, Storage 89.60 89.60


RICE MILLINZGEXANIPLE 3

Page 3 of 3



US $ '000mid-1984 prices

Total

II. Annual Full Development Operating Costs:

Variable Costsproduction labor 15.06auxillary materials (lubrication, spare parts) 18.99power 18.99other 7.59

Sub-Total Variable Costs 60.63

* Fixed Costsmanagement staff 5.44maintenance and repair 2.41building maintenance 4.43mill overheads 14.18

Sub-Total fixed Costs 26.46

Total Operating Costs 87.09

DATA SOURCE: Adapted from Wlorld Bank appraisal report I-o. 5227-BU Burma Grain Storage and Processing Project,Project Implementation Volume, Anne: A FinancialProject Cost Estinates, Sections 1 and 6.

NOTES:Exchange rate - Kyats 7.9 = US $ 1.00Detailed breakdown between local/foreign operating costs notpresented in appraisal report.Data are net of contingencies.

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ANNEX II:

CONVERSION TABLES

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WEIGHTS AND MEASURES

* avoirdupois

Ton: short ton 20 short hundredweight, 2000 pounds;0.907 metric tons;

long ton 20 long hundredweight, 2240 pounds;1.016 metric tons.

Hundredweight cwt;short hundredweight 100 pounds, 0.05 short tons; 45.359

kilograms;long hundred weight 112 pounds, 0.05 long tons; 50.802

kilograms.

Pound lb or lb av; also #;16 ounces, 7000 grains; 0.453 kilograms.

Ounce oz or oz av;16 drams, 437.5 grains; 28.349 grams.

Dram dr or dr av;27.343 grains, 0.0625 ounces; 1.771 grams.

Grain gr;0.036 drams, 0.002285 ounces; 0.0648 grams.

Troy

Pound lb t;12 ounces, 240 pennyweight, 5760 grains; 0.373kilograms.

Ounce oz t;20 pennyweight, 480 grains; 31.103 grams.

Pennyweight dwt also pwt;24 grains, 0.05 ounces; 1.555 grams.

Grain gr;0.042 pennyweight, 0.002083 ounces; 0.0648 grams.

METRIC SYSTEM

Square kilometer sq km or km2 ;1,000,000 square meters;0.3861 square mile.

Hectare ha;10,000 square meters;2.47 acres.

Hectoliter hl;100 liters; 3.53 cubic feet; 2.84 bushels;

Liter 1;1 liter; 61.02 cubic inches; 0.908 quart(dry); 1.057 quarts (liquid).

Deciliter dl;0.10 liters; 6.1 cubic inchs; 0.18 pint(dry); 0.21 pint (liquid).

Centiliter cl;0.01 liters; 0.6 cubic inch; 0.338fluidounce.

Metric ton MT or t;1,000,000 grams; 1.1 US tons.

Quintal q;100,000 grams; 220.46 US pounds.

Kilogram kg;1,000 grams; 2.2046 US pounds.

Gram g or gm;1 gram; 0.035 ounce.

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ANNEX III:

RICE CONVERSION FACTORS

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Factors Relating to Rice Content of Specified Products 1/Source: USDA (1979)

X : Factors for converting--Hundredweight Pounds of Pounds of Pounds of

Product of rough rice product to : milled rice product toto pounds hundredweight to pounds pounds ofof product : of rough rice of product : milled rice

Rice, rough 100.0 0.01000 1.5038 0.6650Brown 82.0 .01220 1.2330 .8110Milled 2/ : 66.5 .01504 1.0000 1.0000Brewers 3.0 .33333 .0451 22.1667Bran : 10.9 .09174 .1639 6.1009Polish 1.6 .62500 .0241 41.5625

Rice grits 69.5 .01439 1.0451 .9568Rice flour 64.2 .01558 .9654 1.0358Rice starch 49.1 .02037 .7383 1.3544

Precooked rice . 63.9 .01565 .9609 1.0407Dehydrated precooked rice 60.5 .01653 .9098 1.0992

Rice cereals, ready-to-serve:Puffed rice 66.5 .01504 1.0000 1.0000Rice flakes 61.2 .01634 .9203 1.0866

1/ Rice conversion factors vary substantially depending on the type and varietyof rice milled. These data are based on national averages over a period of time andare not a perfect measure of any crop's milling yield.

2/ Excluding brewers' rice;

Note: Miscellaneous factors relating to rice:

1 bushel rough rice equals 45 pounds1 hundredweight rough rice equals 100 pounds

or 2.22 bushels1 barrel rough rice equals 162 pounds

or 3.6 bushels

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Documents

World Bank DocumentBran A milling by-product consisting of the outer layers of the kernel and part of the germ. Brewers The smallest fragments of broken rice kernels after milling;