RB in Poultry Feed_4

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Rice bran: Composition and potentialfood usesR. M. Saunders aa United States Department of Agriculture, Western RegionalResearch Center, Albany, California

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Food Reviews International, 1(3), 465-495 (1985-86)

RICE BRAN: COMPOSITION AND POTENTIALFOOD USES

R.M. SAUNDERSWestern Regional Research CenterUnited States Department of AgricultureAlbany, California

Abstract

Qualitative and quantitative aspects of proteins, carbohydrates,lipids, vitamins, minerals, and antinutritional factors in rice branand its subfractions are described. The nutritional value meas-ured in animal feeding tests is summarized for bran, defattedbran, stabilized bran, and protein concentrates derived by alka-line extraction of bran. Stabilization of rice bran and how thisprocess may lead to a quantum change in its utilization in foodsand for recovery of edible oil is discussed. Present uses of ricebran in foodstuffs are described.

465

Copyright © 1986 by Marcel Dekker, Inc. 8755-9129/85/0103-0465$3.50/0

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466 SAUNDERS

INTRODUCTION

Increased food production is a major focus of development programs in mostcountries. While the primary emphasis of these programs is usually increasedcrop production, improved utilization of available commodities (particularlycommodity processing byproducts) could contribute substantially to increasingfood availability. Current (1984) world production of rice is estimated to be inthe order of 420 million metric tons (MMT). This rice, rough rice or paddy,consists of a white starchy endosperm kernel surrounded by a tightly adheringbran coat, an adhering gram, with the total enclosed within a loose outer hull,or husk. All rice is milled prior to consumption, producing hull, bran, germ,and white rice. While a small amount of rice is consumed as brown rice, whichstill contains the bran and germ, white rice is the principal food staple of over2 billion people worldwide (1-3).

Rice hulls, which comprise about 25% by weight of paddy, are composedmainly of cellulose, lignin, and siliceous ash, and have feed and other industrialuses but no food value (4).

Rice bran and rice germ, on the other hand, are rich in protein, lipids, vita-mins, and trace minerals (2). These qualities lead to a high demand for theserice-milling byproducts as animal feed, and they are used extensively, thoughnot exhaustively, for this purpose throughout the world. Frequently thesemilling byproducts are discarded, or at best used for fuel or fertilizer (5).

The quantity of bran and germ available from rice-milling operationsthroughout the world is estimated to be on the order of 30 MMT, representingapproximately 4.5 MMT each of protein and oil. Yet except for limited excep-tions, notably Japan, neither bran, nor germ, nor their associated nutrients areconsumed as foods. Paradoxically, nutrient deficiencies tend to be concen-trated in areas where rice is consumed heavily (3). Those nutrients present inbran and germ would help alleviate nutritional deficiencies if the means couldbe found to consume them in foods, but with rare exceptions bran is not con-sumed as food. This is due to the high fiber content and possible hull con-tamination and to the rapid development of rancidity and free fatty acids.The properties of rice bran and the obstacles to its utilization as a food arediscussed in this chapter. The technologies developed to overcome theseobstacles are described in varying degrees of detail in order to support thepotential of rice bran and germ for direct food application.

A rice kernel is shown diagrammatically in Figure 1. Figure 2 is a photo-micrograph of a section of a dehulled (brown) rice kernel.

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RICE BRAN: COMPOSITION AND USES 467

PERICARP

STARCHY ENDOSPERM

LEMMA(HULL)

EMBRYO (GERM)

PALEA(HULL)

Figure 1. Diagrammatic representation of a rice kernel.

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BRAN

ALEURONE ENDOSPERM

PERICARP SUBALEURONE

Figure 2. Partial cross-section of a brown rice kernel (light microscopy).

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RICE BRAN

Production and Composition

The term bran1 is generic. The final physical and chemical nature of bran de-pends upon rice variety, treatment of the grain prior to milling, type of millingsystem, degree of milling, and fractionation processes operative during milling.Figures published on the composition of bran show a wide variation (Table 1),which reflects the influence of these variables upon the final bran constituents.Because of such variation it is standard market practice to specify limitcomposition. For example, in the U.S. such limits for rice bran may be fat andprotein not less than 12%, ash not more than 17%, and fiber not more than12%. This practice often leads to deliberate adulteration of clean bran withhulls as a profitable venture. The latter action would negate the use of suchbran for direct food use.

In developing countries and to a considerably lesser extent in developedcountries, rice is milled in one-stage (huller) mills that remove a single by-product mixture of hulls, bran, and germ during the production of white rice.Hand-pounding of rice as a means of milling also produces this same mixture ofhulls, bran, and germ. While it is difficult to assess how much of the world'srice is milled by these one-stage operations, it is likely that 70-80% is milledin this manner (5). It is unlikely that this rice-milling byproduct mixture ofbran and hulls would ever find use as a food source. Even if the mixture isseparated into coarse and fine fractions, little difference is noted in composi-tion between the fractions (7). The apparently insurmountable problem ofremoving hull fragments from bran has led investigators to regard utilizationof bran as a food source from hand-pounding or huller mills as impossible (8,9). In this case, the revised potential for utilization of rice bran as currentlymilled as a food source would realistically be in the order of 25% of the num-bers noted earlier (Introduction), or about 8 MMT bran, containing 1.3 MMTprotein and 1.4 MMT oil.

However, the use of two-stage or multistage rice mills in which bran and hullsare removed and recovered separately during the milling process to producewhite rice is growing. These milling operations first remove the hulls (orhusks), either by a disc husker or a rubber roll husker. The latter unit is thepreferred system in any new modernization of rice-milling operations. Priorremoval of the hulls provides a clean brown rice, which in subsequent debran-ning (whitening) operations yields a bran with minimal hull contamination,

1 Unless specified otherwise, rice bran denotes bran from both raw and parboiled rice and containsgerm and polish. The author is indebted to his colleague De Irving for supplying Figures 1 and 2.

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470

Table 1. Range

Range

MinimumMaximum

in Composition

Protein (%)

6.7d; 11.517.2

of Rice Brana>b

Fat (%)

4.7d; 12.822.6

Fiber (%)

6.214.4;26.9d

Ash (%)

8.0I7.7;22.2d

SAUNDERS

NFEC (%)

33.553.5

aRef. 6; compiled from data from India, Italy, Malaysia, Mexico, Nepal, Philippines, Spain, Sri Lanka,and U.S.A.

bDry basis.cNitiogen-fiee extract.dHuller-type mills.

which is then theoretically suitable for exploitation as a food resource. Whiten-ing (or pearling) of brown rice produces bran. This bran is a fine powderymaterial, made up of pericarp, aleurone, pulverized germ, and some endosperm(white rice fragments). A detailed histological and histochemical study of thecaryopsis fragments in rice bran has been published (6). The amount of brokenrice in the bran depends on the rice variety and care taken during milling but isprimarily influenced by temperature and moisture conditions during the paddydrying cycle (10,11). In most milling operations (>99%) the germ becomespart of the bran stream, although in a few instances the germ is separated.

Whiteners, or removers of bran (and germ) from brown rice, are of twotypes: the abrasion type, such as the cono-mills, and the friction type, such asthe polishers or jet pearlers. Proximate analysis of bran from the two types ofwhiteners is shown in Table 2. In some instances calcium carbonate is added asa milling aid; its presence modifies the resultant bran composition (6).

The yield and composition of bran produced in two-stage or multistagemilling varies with the degree of rice milling practiced. In general, paddy rice

Table 2. Proximate Analysis of Rice Branfrom Friction-Type and Abrasion-TypeMillsa

Component

MoistureProteinFatFiberAshNFE

Friction (%)

11-1314-1618-218-109-12

33-36

Abrasion (%)

12-1413-1614-199-108-9

45-50

aAdapted from Ref. 12.

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Table 3. The Degree of Milling(Percent Removed as Bran) inRice in Different Countries

Country

India3'b

Indonesia8

Japana'c

Koreaa'c

LiberiaPakistana

Perub

Philippines3

Spain"Sri Lankaa>b>c

Taiwana

Thailanda'b'c

U.S.A.

PercentRemoved

4 - 647-97 - 84 - 644 - 678477-98-10

aSeeRef. 13.bSee Ref. 5.cSee Ref. 14.dSeeRef. 12.

yields theoretically 25% hulls, 65% white rice, and 10% bran, which includesgerm and polish. These figures might be encountered in a sophisticated com-mercial enterprise. However, in practice the degree of milling (or the amountof bran removed from the brown rice kernel) varies considerably (Table 3).As a consequence, the yield and amount of germ and/or polish in the branvaries, as does the bran composition. The extent of variation in bran composi-tion as a function of the degree of milling is apparent in Table 4. A low degreeof milling (undermilling) is practiced usually for economic reasons; less branremoval, with low market value, means more rice, with high market value. Ahigh degree of milling tends to be practiced where rice is intended for exportor enters marketing channels in which there is a requirement for considerableshelf storage time. Undermilled rice is less stable than well-milled rice becauseof the bran residues left on the kernel. The consumer of rice does, however,benefit from undermilling, since vitamins, protein, lipids, and trace mineralsare left in the bran fragments still adhering to the kernel.

In those limited instances where polish is separately collected during millingof the rice kernel, the polish composition would approximate (dry basis):protein, 14%; fat, 14%; fiber, 3%; and ash, 8% (2,16). Polish is that fraction of

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Table 4. Variation in Rice Bran Composition as a Function of the Degree of Rice Millinga

Bran Composition

Degree of Milling Protein Fat Fiber Ash NFE

1st cone2nd cone3rd cone4th cone

0-33-66-99-10

17.017.617.016.7

17.717.116.514.2

10.510.35.75.7

9.89.48.47.5

45.045.252.555.9

aAdapted from Ref. 15. Dry basis.

the kernel where the endosperm and pericarp are joined together. Thus, polishwould be relatively rich in aleurone and subaleurone material.

In general, bran from parboiled rice contains substantially more oil than doesbran from raw rice. Raghavendra Rao et al. (17) report oil content of par-boiled rice bran to range from 28.2-34.2% compared to 24.2-25.9% for rawbran at up to 5% degree of milling, although these oil contents are abnormallyhigh in either case. Benedito de Barber et al. (18) reported an oil content in rawbran of 19.9% versus 23.1% for the parboiled bran at 4% degree of milling. At4-9% degree of milling, these oil levels were 12.9% (raw bran) and 13.9% (par-boiled bran). Migration of fat from the aleurone cells to the outer bran layersduring parboiling, while difficult to perceive, is generally accepted as the maincontributor to the phenomenon (19). Bran from parboiled rice contains lessstarch and thus less nitrogen-free extract, but more fiber, ash, and protein.Less endosperm fragments (starch) show up on the bran because parboiled ricesuffers less breakage during mUling.

It must be emphasized that in the following section on rice bran compo-nents, the term bran means the bran stream produced in a two- or multistagerice mill. This bran would be expected to contain the germ.

Protein

Protein distribution within the dehulled rice kernel ranges approximately: bran(including germ and polish), 17-30% (16) and milled rice, 70-83% (16). Thisdistribution varies with the degree of milling, and to a lesser extent with thevariety and protein content of the grain. The distribution of protein solubilityfractions in bran has been reported (20) to be albumin, 37%, globulin, 36%,prolamin, 5%, and glutelin, 22%. Values for albumin, 40%, globulin, 21%,prolamin, 3%, and glutelin, 36% were found elsewhere (21). Resolution of

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albumins and globulins and their molecular weights have been reported (22,23).

The major soluble basic proteins of bran have been described as cytochromeC and a blue, copper-containing glycoprotein (24,25).

Nonprotein nitrogen accounts for approximately 16% of the total nitrogenof rice bran (26). Major free amino acids are glutamic acid, alanine, and serine(27).

Rice bran contains numerous enzymes, some of which are likely to be atleast partly of microbial origin. Akazawa (28) has compiled a list of theseenzymes. The enzyme lipase is the most responsible factor in the nonutiliza-tion of rice bran as a foodstuff (see Rice Bran Stabilization section).

The protein (N X 5.95) content of rice bran usually ranges between 9 and17%, although it can be closer to 20% in defatted bran. Protein content is influ-enced by variety, environment, and nitrogen fertilization.

The amino acid composition of rice bran protein is listed in Table 5.

Carbohydrates

Major carbohydrates in commercial bran are celluloses, hemicelluloses (orpentosans), and starch. Starch is not botanically present in the outer pericarplayers, but because of endosperm breakage during milling appears in the bran.The quantity varies according to the amount of breakage and degree of milling,but values of 5-35% could be expected. In an efficient two-stage millingoperation, values of 5-15% would be more likely. Amylose and amylopectincomponents in the starch depend on the rice variety. In general, amylosecontent would be close to zero in waxy (sweet) varieties, although values ashigh as 5.7% have been reported (29), about 10-20% in short- and medium-grain varieties, and 20-35% in long-grain varieties.

Pentosans have been reported to comprise 8.7-11.4% of bran (30). Thewater-soluble hemicelluloses have an arabinose:xylose ratio of 1:8, and containgalactose and protein (31). Alkali-soluble bran hemicelluloses contain 37%arabinose, 34% xylose, 11% galactose, 9% uronic acid, 8% protein, and a traceof glucose (32). Bran cell wall preparations contained hexosans (27-28%),pentosans (30-34%), protein (8-9%), and uronic acid polysaccharides (5-9%)(33). Sugars present in these polysaccharides were arabinose (27-31%), xylose(26-29%), glucose (30-36%), galactose (6-9%), and mannose (2%). Ferulicacid was present in these cell wall preparations. Other works have shown thatpectic polysaccharides containing rhamnose, fucose, arabinose, xylose,galactose, glucose, and uranic acid are present throughout the dehulled ricekernel (34).

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Table 5. Amino Acid Composition ofRice Brana>b

Amino Acid

LysineHistidineAmmoniaArginineAspartic acidThreonineSerineTryptophanGlutamic acidProlineGlycineAlanineValineCysteineMethionineIsoleucineLeucineTyrosinePhenylalanine

% N recovered

Average

3.88C

2.111.726.507.623.06d

4.241.70

12.844.104.525.675.451.632.223.94e

6.963.654.47

85.6

StandardDeviation

0.820.570.961.312.030.690.730.512.861.010.861.220.430.580.350.541.441.280.85

11.3

aAdapted from Ref. 12.bg/16.0gN.cFiist limiting amino acid; Chemical Score 71."Second limiting amino acid; Chemical Score 77.eThiid limiting amino acid; Chemical Score 99.

Cellulose in bran is reported to range from 9.6-12.8% (30) and is concen-trated in the pericarp-seed coat fraction. Beta-glucans appear in endospermcell walls (34). Lignin content of bran ranged from 7.7 to 13.1% (35). Proteo-glycans rich in hydroxyproline and arabinose have been isolated from rice bran(36,37).

Free sugars in rice bran are concentrated in the aleurone layer and are re-ported to range from 3-5%. Glucose, fructose, sucrose, and raffinose have beenreported (38). Nonreducing sugars are more abundant than reducing sugars.Saunders (21) found 8% sugar in bran (dry basis), of which 80% was sucrose,5% raffinose, 15% higher oligosaccharides, and only a trace of glucose andfructose.

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Lipids

Bran typically contains 10-23% oil, although the value may exceed 23% inundermilled, parboiled bran. Three major fatty acids, palmitic, oleic, andlinoleic, make up about 90% of the total fatty acids (Table 6). Rice bran oilis close in composition to sesame, corn, cottonseed, and peanut oils.

Bran lipids are classified into the groups glycerolipids, sterol lipids, andsphingolipids. The glycerolipids comprise glycerides (89%), glycolipids (8%),and phospholipids (2%) (43). The glycolipids include predominantly mono-and diglycosyldiglycerides, the sugars of which are galactose and glucose.Phosphatidyl-choline, -ethanolamine, and -inositol comprise the phospho-lipids (44). In the sterol lipid group, free sterols, sterylglycosides, and acyl-sterylglycosides are present (45). Ceramides and glycosylceramide make upmost of the sphingolipid class (45). Cholesteryl esters and cholesterol have beenidentified in rice lipids (46). A potent antioxidant, oryzanol, is reportedlypresent at 1 - 3 % in bran lipids (47).

Rice bran oil contains wax (2-5%). The major wax acids are behenic, cerotic,isocerotic, and lignoceric, whereas the alcohols include ceryl, isoceryl,montanyl, and myricyl (42).

Lipids in milled bran are rapidly hydrolyzed by the action of lipases. Thissubject will be discussed in detail in the section on Rice Bran Stabilization andRecovery of Edible Oil.

Comprehensive reviews are available on rice lipids (44,48,49).

Table 6. Fatty Acid Composition of Rice Bran Oil

Fatty Acid

Myristic(C14:0)Palmitic (Cl 6:0)Palmitoleic(C16:l)Stearic(C18:0)Oleic (C18:l)Linoleic (Cl8:2)Linolenic(C18:3)Arachidic (C20:0)

Composition (%)

Rangea

0.4-1.012-16

0.2-0.61-3

40-6029-42

0.5-1.00

Typical

tr15.9—1.7

40.737.9

1.40.6

aSeeRefs. 39,40,41,42.

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Vitamins

Vitamins found in rice bran have been tabulated by Juliano (16). Ranges forthese values are listed in Table 7.

Variation in vitamin content undoubtedly reflects analytical methodology,rice variety, degree of milling, and hull contamination. However, it is clear thatall vitamins are concentrated in the outer kernel layers, principally in thealeurone layer and scutellum. By calculation, the bran-germ-polish componentcontains 78% of the rice kernel thiamine, 47% of the riboflavin, and 67% ofthe niacin. It has been reported (50) that rice milling results in the loss tohuman consumption of 76% thiamine, 57% riboflavin, and 63% niacin. Similarlosses would occur in all other vitamins because of their concentration in thebran and germ.

Thiamine, riboflavin, and niacin are substantially lower in parboiled branthan in regular bran (50).

Minerals

Juliano (16) has tabulated mineral analyses for rice bran, the ranges for whichare listed in Table 8. Minerals are concentrated in the kernel bran layers. Thebran-germ-polish fraction contains about three times the mineral content ofmilled white rice. Phosphorus is the major mineral, about 90% of which is

Table 7. Vitamin Content of Rice Brana

Vitamins

Vitamin AThiamineRiboflavinNiacinPyridoxinePantothenic acidBiotinMyoinositolCholinep-Aminobenzoic acidFolic acidVitamin B i2

Vitamin E (tocopherols)

Content(ppm, dry basis)

4.210.1-27.91.7-3.4

236-59010.3-32.127.7-71.30.16-0.60

4,627-9,2701,279-1,7000.75

0.5-1.460.005149.2

aSeeRef. 16.

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Table 8. Minerals in Rice Brana

Component

AluminumCalciumChlorineIronMagnesiumManganesePhosphorusPotassiumSiliconSodiumZinc

Content (ppm)

53-369140-1310510-970190-530

8,650-12,300110-877

14,800-28,68013,650-23,9601,700-16,300

0-29080


phytate phosphorus (16). Silicon would be expected to vary widely since it isa major component of rice hulls.

Mineral concentration varies with the degree of milling. Some elements (P,K, Mg) increase initially, then decrease with increasing degrees of milling;others (Ca, Mn, Fe) show early sharp decreases (51). Mineral composition alsovaries with the soil environment. Milling would result in a loss to human con-sumption of the majority of rice minerals. For example, by calculation, about80% of the iron is in the bran fraction.

RICE BRAN FRACTIONATION

Considerable research has been reported on conversion of rice brans into sub-fractions which may contain more of the desirable nutrients and less of theundesirable components. Protein has been generally used as an index of positiveenrichment, which in some cases has led to the term "protein concentrates"being applied to some bran subfractions. Fiber has generally been consideredan index of undesirable components, although this has been modified to someextent in recent years because of the purported desirability of dietary fiber.

Fractionation processes include specialized dry milling of raw or parboiledbrown rice, air-classification of rice brans, and aqueous extraction of brans atambient or alkaline pH followed by recovery of fractions differing in theirsolubility or emulsification properties. None of these processes has beenadopted by commerce to any great extent.

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Dry Fractionation

The separate collection of individual bran streams from different abrasive(whitening) cones encountered in some milling operations can provide branfractions of differing composition (52). However, with the exception of ricepolish, which is sometimes collected separately, individual collection of branstreams is not practiced. Even the theoretical opportunity to collect bran sub-fractions during milling of brown rice is absent in the majority of rice-millingoperations.

Fractionation of bran via particle size classification has not been particularlysuccessful. Houston and Mohammad (53) sieved a defatted rice bran (10.6%protein) through a 40-mesh screen, providing 52.5% of the material as aproduct containing 13.4% protein and 8.7% fiber. Air-classification of finelyground defatted rice bran (10.6% protein; fiber 11.4%) provided a high protein(12.3%) fraction in a 48% yield, containing 6.9% fiber (53).

Through pin-milling and air-classification, defatted rice bran of original pro-tein and fiber contents of 19.4% and 8.2%, respectively, was converted intosubfractions containing protein as high as 23.5% and fiber as low as 1.9% in50% yield (Table 9). Unfortunately, the ash content of the protein-enrichedsubfractions is probably too high for direct food application.

Fine grinding and air-classification of full-fat rice bran did not provide frac-tions of composition different from that of the starting bran (53,54).

Wet Fractionation

Wet grinding of full-fat rice bran using disk, rotating, or colloidal mills fol-lowed by wet-particle size classification using meshes or hydrocyclones yielded

Table 9. Air-Classification of Pin-Milled Defatted Rice Brana

Fractionb

CoarseFineCoarseFineCoarseFine

Yield(%)

505052488614

Protein(%)

16.723.515.623.619.517.7

Fiber(%)

14.11.9

13.92.68.84.1

Ash(%)

_

21.1—

21.4-—

aSee Ref. 54."Runs at different settings for separation of fractions.

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Table 10. Yield and Composition ofWet Processing of Full-Fat Rice Bran

Material

Starting branHigh-fiber fractionLow-fiber fractionAqueous concentrate

Yield

100325711

Fractionsa

Protein

14.513.116.96.1

Derived by

Fat

14.613.017.16.3

Fiber

9.517.83.00.5


three fractions: (1) a high-fiber fraction, (2) a low-fiber fraction, and (3) anaqueous concentrate of vitamins and minerals (Table 10) (6). Unfortunatelythis process suffers from the associated high drying costs.

Protein concentrates of various compositions have been prepared from full-fat and defatted rice bran by an alkaline extraction technique similar to theprocess of preparing protein isolates from soybeans. Solubilization of nitrogenin rice bran as a function of pH has been investigated (55,56). Earlier, condi-tions had been recommended for alkaline extraction of rice brans, namely pH 9at room temperature for 15 min (57). This process has been patented (58).These conditions were deemed appropriate for economic purposes and for theavoidance of negative amino acid-alkali reaction products. Screening of theaqueous alkaline mixture to remove particulate (fiber) material provides anaqueous phase containing a major portion of the original bran protein, lipid,and starch. A protein-lipid-starch concentrate could be obtained from theaqueous phase by heat or acid precipitation (Table 11). Removal of starch priorto protein precipitation altered the protein composition as shown in Table 11.Lipid extraction from these protein concentrates would increase the final pro-tein level.

The composition of the fatty acids in these subfractions averaged oleic,48.9%, linoleic, 37.0%, palmitic, 14.1%, and traces of steric and linolenic,similar to the rice bran pattern (Table 6) (57). The amino acid patterns ofthese subfractions and those of the bran from which they were prepared arelisted in Table 12. Lysine is no longer the first limiting amino acid in the sub-fractions. The subfractions are enriched in iron (57).

To decrease water required for processing (and hence drying costs), thisprocess was refined to provide a liquids recycle operation (57,58). A formula,y = x (1.97n + 4.35) was determined, where y equals the weight of aqueousalkali, x equals the weight of rice bran, and n equals the recycle batch number.In practice, the solids content of the recycling liquid phase leveled off at cycle

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Table 11. Yield and Composition of Fractions Obtained from Rice Bran byAlkaline Extraction8

Bran Recovery Procedure

Rice branHeatHeat, starch removedAcidAcid, starch removed

Defatted rice branHeatHeat, starch removedAcidAcid, starch removed

Yield(%)

20.512.216.812.3

20.59.3

16.811.0

Protein(%)

22.833.328.235.8

33.758.243.062.3

Fat(%)

32.749.241.750.8

8.216.212.217.7

Fiber(%)

0.70.51.00.6

1.61.01.60.6

Ash(%)

11.74.55.23.3

17.06.15.73.4

Starch(%)

22.91.3

20.41.5

25.53.2

29.71.6

aAdapted from Ref. 57. Dry basis.^This bran actually contained 5.4% fat.

Table 12. Amino Acid Content of Rice Bran and Subfractions Preparedby Extraction of Rice Bran at pH 9 a 'b

Amino Acid

LysineHistidineAmmoniaArginineAspartic acidThreonineSerineGlutamic acidProlineGlycineAlanineValineIsoleucineLeucineTyrosinePhenylalanineCysteineMethionineNitrogen recovery (%)

Rice Bran

4.41C

2.421.927.199.563.694.52

13.093.795.276.185.853.53d

6.722.544.202.241.83

85.65

Bran Subtraction

Heat-Precipitated

5.192.921.498.808.503.54C

4.6413.624.585.716.236.293.69d

6.973.274.641.721.76

90.68

Acid-Precipitated

5.082.971.498.698.153.62C

4.5514.163.665.546.006.093.72d

6.843.044.151.821.66

88.47

aAdapted from Ref. 57.bg/16gN.cFirst limiting amino acid; Chemical score, 81 (bran); 89 and 91 (subfractions).^Second limiting amino acid; Chemical score, 88 (bran); 92 and 93 (subfractions).

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Table 13. Yield and Compositions of Fractions Prepared from Rice Bran byExtraction with Sweet or Acid Wheya

Whey Type

Sweet wheystarch presentstarch absent

Acid wheystarch presentstarch absent

Yield(%)

23.18.5

21.86.7

Protein(%)

23.347.8

34.054.1

Fat(%)

31.046.4

24.032.1

Fiber(%)

2.00.1

3.20.4

Ash(%)

8.61.5

11.53.2


5, at 6.5% solids, half of which was sucrose, glucose, fructose, and raffinose(57).

Subfractions from bran and defatted bran also have been prepared viaalkaline extraction by Chen and Houston (59) and Lynn (60), respectively.Yield and composition were similar to those products described in detail above.

Whey adjusted to alkaline pH has been used to extract rice bran as a meansof deriving subfractions enriched in protein (61-63). Typical yields and com-positions are reported in Table 13 for these materials with and without starchremoval during the extraction procedure.

Several enzymes have been tested in an effort to improve extractability ofprotein from rice bran. Amylases showed some improvement, whereas cellu-lases, proteases, and pentosanases did not (60,64). Use of hydrogen peroxide(65) or fine grinding (55) did not improve protein extractability from ricebran, although fine grinding did improve extractability from purified rice germ(55).

Mitsuda et al. (66) report high-protein subfractions recoverable from ricebran by extraction with sodium dodecyl sulfate, ammonium hydroxide, sodiumhydroxide, sodium chloride, or urea. Yields ranged from 14 to 30%. Alcoholextraction of the material extracted with sodium hydroxide yielded a proteinisolate, 94-99% protein. Incorporation of an anion-exchange resin in theextraction medium improved protein recovery.

Another process to wet-fractionate rice bran has been described by Mihara(67). Bran is first ground in water, then separated into aqueous and solid phasesby centrifugation. From the aqueous phase, a protein-oil complex is removedby chemical means, then deoiled to produce a protein concentrate and oil.Phytin is recovered by precipitation, leaving a vitamin-enriched aqueous phase.Starch is further fractionated from the solid phase by resuspension and particle-size classification. The yield and composition of subfractions are listed in

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Table 14. Wet Fractionation of

Bran Subfraction

ProteinStarchPhytinOilVitamin concentrateSolids residue

Yield(%)

11.014.58.0

16.522.025.0

Rice Brana

Water(%)

8.65.4n.a.n.a.n.a.2.2

Protein(%)

78.51.60n.a.

11.213.1

Fat(%)

1.80.50n.a.n.a.6.8

Fiber(%)

01.70n.a.0

26.3

Ash(%)

2.90.7

41.2 .n.a.n.a.2.6

SAUNDERS

Carbohydrate(%)

8.390.10n.a.

87.348.8

aAdapted from Ref. 67. n.a., not available.

Table 14. This process is complicated, requiring substantial drying, and is thusnot likely to be economic.

Organic Solvent Fractionation

Rice bran disintegrated in hexane with a high-speed blender was sieved through60-mesh screens. The fraction passing through the 250-mesh screen, afterhexane removal, yielded (35-40%) a product containing 22% protein, 50%carbohydrate (80% starch), 4% fiber, and 20% ash, dry basis (68).

RICE BRAN STABILIZATION

The utilization of rice bran as a food is limited to some extent by its fibercontent, but the major obstacle is its instability. Enzymes, both natural to thebran and of microbial origin, are the major cause of bran deterioration. Lipases,and to a much lesser extent oxidases, are responsible for these deteriorativechanges by promoting hydrolysis of the bran oil into glycerol and free fattyacids (FFA). Hydrolysis and oxidative rancidity are associated with this de-terioration. The consumer experiences bitterness and a soapy taste (6). Withinthe intact rice kernel, lipases are localized in the testa-cross layer region, whilethe oil is localized in the aleurone and germ (69). Thus, the substrate andenzyme are compartmentalized. However, once these regions are disruptedduring the milling process, enzymatic hydrolysis is possible and proceedsrapidly. Microorganisms present on the surface of the kernel would also thenhave access to the bran oil (70).

One process to avoid this problem has been commercialized, namely theX-M Process, in which rice is milled under hexane (71). In this manner, the

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oil is separated from the bran during the milling operation to produce an oilwhich can be directly refined for edible purposes. The bran from this operationcan then be desolventized (via heat) to provide defatted rice bran, which infact has some food applications. Because of poor economics, the X-M Processis no longer in operation.

Thus, throughout the world, lipase and bran oil do come into immediatecontact once the rice is milled. The rate of FFA release is very high and isaffected strongly by environmental temperature and moisture. FFA release of5-7% in a single day or up to 70% in a month has been widely recorded. AsFFAs increase, the refining loss for potential edible oil production increasesmore rapidly since losses during refining are two to three times the FFApercentage (9). Rice bran oil normally contains 1.5-2% FFA at the time ofmilling; less than 5% FFA is desirable in the crude oil for economic recoveryof refined edible oil (9).

These deleterious enzymes in rice bran can be destroyed by heat. In practice,this heating (stabilization) must be done in as short a time as possible aftermilling, and thus prior to appreciable accumulation of FFA. Cost-effectivestabilization of rice bran immediately after milling would singularly transformrice bran into a food resource with worldwide impact (9,72). This has longbeen recognized by investigators, and numerous bran stabilizers have beendeveloped.

Stabilization Processes

Procedures to stabilize rice bran through heat-treatment include retained-moisture heating, added-moisture heating, and dry heating. These systems aretabulated in Table 15. With the exception of the microwave and infraredheating devices, the advantages and disadvantages of these various stabilizationsystems have been discussed (72). The microwave system suffers from the highcost of magnetrons, which have a limited life, and the need fo further pelletizethe bran prior to oil extraction. Likewise, the infrared system suffers from theshort life of the infrared lamps, the high cost of replacement, and the needto further pelletize the bran prior to extraction of oil. Perhaps the mostsomber observation is that none of the systems developed during the sixtiesand seventies have been accepted commercially and thus presumably areuneconomic.

Dry heating is attractive because of its simplicity of operation and thegeneral availability of hulls as a fuel source, but reports on effectiveness ofstabilization are conflicting. Added moisture methods are effective, but steamis required, and bran must be dried after steaming. Systems that retain theambient moisture under pressure at high temperature and then utilize the

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484

Table 15. Rice Bran Stabilization Processes

Stabilization Method

Retained-Moisture Heating Methods

Extrusion cookers: Brady extruder (continuous)Extrusion cooker: Kist extruder (continuous)Rotating drum (batch)Microwave tunnel (continuous)Infrared heat (continuous)

Added-Moisture Heating Methods

Screw conveyors (continuous)Extrusion cooker: Anderson extruder (continuous)

Dry-Heat Methods

Open-pan roasting (batch)Stationary bed (batch)Steam-jacketed conveyor (continuous)Flu-gas-jacketed screw conveyor (continuous)Oil-jacketed screw conveyor (continuous)Fluidized bed (batch)

SAUNDERS

References

9,72,7374757677

78-8283

848586878889,90

added heat to drive off some of the moisture as pressure is released appeareffective and efficient.

Extrusion cooking with low-cost extruders, which run on electricity and inwhich heat is generated through friction with no steam or drying requirement,appear most appropriate (72). Preliminary economic analysis indicated that theuse of such an extrusion cooker in rice-milling operations to stabilize bran foredible oil recovery would be financially feasible (9). This prediction appearsto have been borne out in practice (73).

Only in one case has a thorough economic analysis been made of the sta-bilization system, namely the Brady2 extruder system (9). The simplicity ofthis unit, its low cost,3 and effective stabilization at high-quality continuousthroughput seem to predicate its eventual use in developed and third worldcountries, albeit only at multistage rice mills.

2Reference to a company and/or product named is only for purposes of information and does notimply approval or recommendation of the product to the exclusion of others which may also be suitable.

3 U.S. $15,000 in 1985.

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Table 16. Storage Stability of Stabilized Rice Brana

Test

FFA (%)H2O (%)Bacteria (X 102/g)

Raw Bran

Initial

411

82,000

28 Days

5112

7,400

Stabilized Bran

Initial

379

28 Days

410-114

Stabilized on a Brady extruder; stabilized 10 min after milling (see Ref.73).

Barber and Benedito de Barber (12) point out that research and developmentwork on rice bran stabilization had never gone beyond the heat-stabilizationstage. Recent work on stabilization using the Brady extruder has addressedpoststabilization consequences, including handling, storage stability, oil extrac-tion and refining, chick and pig feeding, and incorporation of stabilized bransinto foods. These are described in some detail below.

In practice, it has been recommended that extrusion at 130°C, followed byholding the bran for 3 min at 97-99°C prior to cooling, effectively stabilizesthe bran (73,91). In this process, a temperature of 130°C is attained entirelythrough friction, and the bran is at this temperature only a few seconds. Sim-ilar conditions were noted in another extruder system (74). In addition todestruction of lipase activity, peroxidase activity was also destroyed underthese extrusion conditions. Long-term storage studies (Table 16) indicatedthat stability against FFA development persisted for at least four months,contrary to most processes using dry heat to stabilize (12). Extrusion-stabilized bran was essentially sterile (Table 16). At these stabilization con-ditions, electrical energy requirement was 0.076 kwh/kg (73). Extrusion-stabilized rice bran contained 6-7% moisture and was in the form of smallflakes, with 88% larger than 0.7 mm in diameter. This material could be ex-tracted with hexane to recover oil without further pelleting (92), in contrastto most other stabilized brans, which require agglomeration or pelleting priorto oil extraction (12). The crude oil was refinable using conventional (40)winterizing, dewaxing, neutralization, bleaching, and deodorization (92).The refined oil compared favorably in color and flavor with other vegetableoils. It contained 170 mg/kg of tocopherols (Vitamin E) and would thus beexpected to be stable. Fatty acid composition of refined oil is shown inTable 6 (under Typical).

Stabilized rice bran and extracted stabilized bran in which oil was addedback in the test showed a 20% improvement in feed efficiency compared tounstabilized bran when fed to chicks at 60% of the ration (93). Stabilized bran

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486 SAUNDERS

was marginally inferior to unstabilized bran when fed at high levels (20-40%)to pigs (94). Elsewhere, Tortosa et al. (95) had shown a slight improvement inpig performance when fed rice bran stabilized by another procedure (79) whencompared to the unstabilized bran.

Stabilized and hexane-extracted stabilized rice bran from the Brady ex-trusion system have been tested in food systems (96,97) (see section on FoodUses).

Recovery of Edible Oil

The prime reason for stabilizing rice bran is to convert this resource into oneproviding edible oil. Edible rice bran oil at present is obtained in Japan andIndia only in those cases where the bran can be extracted within a short timeafter milling prior to FFA buildup. In these cases the bran is steam-agglom-erated (Japan) or pelleted (India) prior to hexane extraction. Oil-refining to ahigh degree is practiced in Japan using either alkali-refining or physical-refining.Cost-effective stabilization technology using extrusion is now available on ascale suitable for small and large two-stage or multistage rice-milling opera-tions. Stabilization at single-stage rice mills is considered impossible due to thepoor economics in extracting rice bran containing hulls and thus having low oilcontent. The extrusion process has the advantage of not requiring additionalpelleting prior to extraction, and in fact the cost of stabilizing is probablysimilar to the cost of pelleting. Extrusion conditions have a positive nutritionaleffect upon the bran as far as poultry feeding is concerned, and no negativeeffects upon swine feeding. Most importantly, the stabilized bran can be storedfor long periods prior to extraction without loss of oil quality (92).

Since the economics appear favorable (9), one can expect that productionof edible rice bran oil will increase in the near future through implementationof low-cost extrusion technology.

NUTRITIVE VALUE OF RICE BRAN

The general nutritive value of rice bran has been well established in composi-tional data and pertinent references listed elsewhere in this chapter. Actualstudies on biological value using test animals is severely limited. Some ideaof energy value and nutrient digestibility as a feed is evident in data listed inTable 17, although bran compositions are not defined and these values arelikely to be low compared with those encountered in a good quality bran. Ifone assumes typical starch and sugar contents to be 10% and 5%, respectively,

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Table 17. Energy Values and Digestibilities of Rice Brana

Digestible Metabolizable Protein Total DigestibleAnimal Energy Energy Digestibility NutrientsSpecies (kcal/kg) (kcal/kg) (%) (%)

Cattle 2,910 2,171 65 66Sheep 3,527 2,632 68 80Swine 3,578 3,028 76 81

aAdapted from Ref. 98; dry basis.

the caloric content of the representative friction-milled rice bran (Table 2) cal-culates to 2950 kcal/kg.

The content (Table 2) and amino acid composition (Table 5) of rice branprotein appears favorable compared to other cereal grains, but protein is oflimited digestibility. The reason for this has not been entirely established, norhas it been confirmed in human studies. However, if protein digestibility islow in animals, it can be expected to be low in humans. Nitrogen digestibilityof rice bran in rats was reported to be 58.5% (57). Titus (99) reported a valueof 59% for chicks and Maymone et al. (100) a value of 60.2% for sheep.Measurement of nitrogen digestibility in rice brans and germ using rats (21)recorded values of 59.5-79.3% for five rice brans, 71.2% for defatted bran, and84.9% for rice germ. Nitrogen digestibility in the protein-enriched fractionsprepared by alkaline extraction of rice bran were 83.4% (heat precipitated)and 89.6% (acid precipitated) (57).

These limited rat-feeding data indicated that protein digestibility in rice-milling products is inversely proportional to the fiber content. This relation-ship exists for wheat-milling products (101). Rice bran protein, which ishistologically associated with the fibrous outer pericarp and/or aleuronelayers, is not readily available to digestion. Rice protein bodies contribute tolow protein digestibility. Most protein in the subaleurone layer, and that whichwould be present in the bran to considerable extent, exists as protein bodies(102). These protein bodies have been shown to be not fully digestible, and thedigestibility decreases further after cooking (103). Tanaka et al. (51) havedescribed rice globoid particles in the aleurone layer which contain substantialphytic acid. Phytic acid has a negative effect upon protein digestibility (104).

Protein efficiency ratios (PER) reported for rice bran, rice polish, rice germ,and bran subfractions enriched in protein obtained by alkaline extraction arelisted in Table 18. The high values reported for PER reflect a protein nutritivevalue one would expect from the amino acid chemical score (Table 12) for

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Table 18. PER Values for Rice-Milling Byproducts and Protein-Enriched Fractions Obtained by Alkaline Extraction of Rice Bran

Rice Material

BranBranDefatted branDefatted branAlkaline extracted

protein-enriched bransubfractions

GermGerm

PER

1.61,1.921.591.7-1.92.071.99,2.19a

2.31,2.36,2.37,2.49a

2.24,2.32,2.38b

1.901.74

Reference

105576021572121

10521

aSix subfractions differing in method of preparation and/or drying,prepared from the same rice bran.

"Three subfractions differing in method of preparation and/or dryingprepared from the same defatted bran.

subfractions prepared from bran. These PER values are extraordinarily high fora material derived solely from a cereal source.

Bran stabilized by the Spanish procedure (Table 15) (79) showed a PERvalue in rats of 1.59 compared to 1.66 for the unstabilized bran (21). Thesevalues were not statistically different, and nitrogen digestibility was the same(73%) for both brans. In another study on these same materials, stabilizationresulted in a small though significant improvement in nitrogen balance but nodifference in PER values in rats (106).

Bran stabilized by extrusion (Table 15) (73) showed a 20% improvement infeed efficiency compared to unstabilized bran when fed to chicks at 60% ofthe diet (93), although it was slightly inferior to unstabilized bran when fedto pigs (94).

In those feeding tests using stabilized bran, no adverse effects upon nutritivevalue through the heating process were observed. On the contrary, antinutritivefactors were destroyed (see next section).

Bioavailability of nutrients other than protein from rice bran has not beenstudied to any extent. Maymone et al. (100) report digestibility by sheep oflipids, crude fiber, and organic matter to be 79.5%, 31.2%, and 59.5%, respec-tively. Crampton and Harris (98) list total digestible nutrients to be 60%(cattle), 73% (sheep), and 74% (swine).

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Antinutritive Factors

Enzyme inhibitors noted in rice bran include trypsin inhibitor (107) and pepsininhibitor (66,104). The pepsin inhibition is believed to be caused by phytatein the bran (104). The trypsin inhibitor is proteinaceous (107). Alpha-amylaseinhibitors like those found in wheat are absent (108).

Other potentially deleterious components in rice bran include hemagglutinin(109), an antithiamin factor (110), and estrogenic activity (111). Trypsininhibitor and hemagglutinin activities were destroyed by heat during thestabilization process (112,113). Chicks fed unstabilized raw bran had a sig-nificantly heavier pancreas than chicks fed stabilized bran (93), though nodifference was noted in pancreatic weight between rats fed stabilized or un-stabilized bran (21). Growth depression in chicks fed raw (unstabilized) branhas been noted frequently (93,114) and occasionally in pigs (6,94). Heattreatment invariably improves feed performance in chicks, even though residualtrypsin inhibitor activity may be present (114).

Phosphorus is the most abundant mineral in rice (Table 8). According toMcCall et al. (115), phosphorus occurs as phytic acid (89.9%), nucleic acid(4.4%), inorganic phosphate (2.5%), carbohydrate (2.3%), and phospholipid(1%). Phytic acid, myoinositol hexaphosphate, occurs entirely in the bran(116) and is associated with the aleurone layer. Bran obtained from 4% degreeof milling had phytic acid content of about 3%, 23 times the level found inwhole brown rice (116). The particles isolated from aleurone by Tanaka et al.(51) contained 9.4% myoinositol and 11.6% phosphorus. Aleurone particlesdescribed by Ogawa et al. (117) contained 67.2% phytic acid, 18.9% potassium,and 10.8% magnesium.

There is controversy concerning phytic acid and nutrient availability. In vitroobservations suggest it is a protease inhibitor, but whether this plays a rolein vivo needs to be substantiated. Far more prevalent in the literature is thequestion of the influence of phytic acid upon mineral availability (118).Phytates have been considered to prevent absorption of mineral elements,particularly divalent elements, and there are numerous studies to support thisclaim. However, Morris and Ellis (119) reported iron in monoferric phytate tobe totally available to rats, and Graf and Eaton (120) report that phytic acidhad no substantial effect upon absorption of calcium or iron in mice.

Dietary Fiber

Only one study has been carried out on the dietary fiber content of rice bran(121). The results are listed in Table 19. From these limited data, a regression

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Table 19. Crude Fiber and Dietary Fiber of RiceBran Measured by In Vivo and In Vitro Procedures

Rice Material

Bran 12345

Defatted branGermBrown rice

Dietary

In Vivob

(%)

48.642.137.829.525.644.317.76.2

Fiber3

In Vitroc

(%)

n.a.n.a.36.432.2n.a.n.a.20.4

7.2

Crude Fiber(%)

14.511.18.87.94.19.83.01.2

aMoisture-free basis. See Ref. 122. n.a., not available.bRats.cSeeRef. 122.

equation was derived in which in vivo dietary fiber (y) is related to crude fiber(x): y = 3.34x + 5.69 (r2 = 0.931).

FOOD USES

Rice bran finds extremely limited use in foods, primarily because of the asso-ciated oil deterioration problem (see section on Rice Bran Stabilization) andhull contamination. Rice polish, though only manufactured in a few locations,finds use in baby foods. Defatted bran use also is extremely limited, but a widevariety of products exist,4 including specialty breads, a carrier for artificialspices, a protein supplement and binder ingredient for meat and sausageproducts, a raw material for production of hydrolyzed vegetable proteins, abreakfast cereal and snack food ingredient, a tableting excipient, a source ofinositol, and an ingredient in pickles (6).

Stabilized rice bran finds limited use in rice flours and breakfast cereals inthe United States.

Numerous potential food uses for full-fat and defatted rice brans have beenwell proven in laboratory tests but not yet in commercial practice. These

4

The author is indebted to Dr. J. Hunnell of Riviana Foods, Houston, for providing some of thisinformation.

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include bread, muffins, pancakes, cookies, pies, and cakes using raw orstabilized full-fat bran (60,96,97). Protein concentrates from bran have beenextensively studied as ingredients in breads, beverages, pasta, and confections(21,60). Levels of up to 10% tended to give satisfactory products from anorganoleptic viewpoint. Nutritionally, protein content was invariably increased.

Oil extracted from bran in Japan is refined and used as an edible oil.Estimates on actual tonnage vary widely, though 10,000 MT per year seemsreasonable. In India, edible oil production from rice bran seems to vary widelyfrom year to year, with not less than 5000 MT per year being produced.

RICE GERM

Only in rare instances is rice germ separated from bran during the rice-millingoperation. This is the case in Spain and Egypt, where the germ commands apremium price as a feed. It is believed that a very small quantity of purifiedgerm finds specialty food use in Japan. The merits of using rice germ as a food-stuff have been thoroughly documented (6,123). Germ is rich in protein(~25%), oil (~30%), and vitamins and trace minerals. It would seem wise todevise and install germ separators for modern rice-milling operations; thenutritional and economic returns appear to warrant such a move.

REFERENCES

1. D. F. Houston, "Rice Chemistry and Technology," Amer. Assn. Cereal Chemists, St.Paul, Minn., 1972a.

2. D. F. Houston and G. O. Kohler, "Nutritional Properties of Rice," Nat. Acad. Sciences,Washington, D.C., 1970.

3. R. M. Saunders and A. A. Betschart, in "Tropical Foods: Chemistry and Nutrition,"Vol. I, G. E. Inglett and G. Charalambous, Eds., Academic Press, New York, 1979,pp. 191-216.

4. D. F. Houston, in "Rice: Chemistry and Technology," D. F. Houston, Ed., Amer.Assn. Cereal Chemists, St. Paul, Minn., 1972b, pp. 301-352.

5. R. M. Saunders, A. P. Mossman, T. Wasserman, and E. C. Beagle, "Rice PostharvestLosses in Developing Countries, U.S. Dept. Agriculture, Agricultural Reviews andManuals, ARM-W-12, 1980.

6. S. Barber and C. Benedito de Barber, in "Rice: Production and Utilization," B. S. Lah,Ed., AVI Publishing Co., Westport, Conn., 1980, pp. 790-862.

7. J. Duckworth and J. M. Dent, Tropical Agriculture, 23:25 (1946).8. H. G. R. Reddy, "Rice Bran Stabilization," UNIDO Ad-Hoc Expert Group Meeting,

Vienna Report ID/.WG.240/3, 1976.9. R. V. Enochian, R. M. Saunders, W. G. Schultz, E. C. Beagle, and P. R. Crowley,

"Stabilization of Rice Bran with Extruder Cookers and Recovery of Edible Oil: A

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Preliminary Analysis of Operational and Financial Feasibility," U.S. Dept. AgricultureMarketing Research Report 1120, 1981.

10. O. R. Kunze, Trans. Amer. Soc. Agric. Eng., 22:1197 (1979).11. O. R. Kunze and S. Prasad, Trans. Amer. Soc. Agric. Eng., 27:361 (1978).12. S. Barber and C. Benedito de Barber, in "Proc. Rice Byproducts Util. Int. Conf. 1974,"

Valencia, Spain, Vol. IV, Rice Bran Utilization: Food and Feed, S. Barber andE. Tortosa, Eds., Inst. Agric. Chem. Fd. Tech., Valencia, Spain, 1977, pp. 1-99.

13. H. G. R. Reddy, F. Gariboldi, and Y. Joko, "Report of the Expert Study Group on theRice Bran Oil Industry," ECAFE-AIDC, Bangkok, Thailand, 1970.

14. D. Garvie, P. K. Kymal, Y. Koga, T. Watanabe, and K. Kabayashi, "Report of theExpert Study Group on Rice Processing Machinery," ECAFE-AIDC, Bangkok,Thailand, 1971.

15. E. Primo, S. Barber, E. Tortosa, J. M. Camacho, J. Ulldemolins, A. Jimenez, andR. Vega, J. Agric. Chem. Fd. Technol., 10:244 (1970).

16. B. O. Juliano, in "Rice: Chemistry and Technology," Amer. Assn. Cereal Chemists, St.Paul, Minn., 1972, pp. 16-74.

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RB in Poultry Feed_4

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