Rice Properties and Processing Bienvenido O

This article was downloaded by: [Tomsk State University of Control Systems and Radio] On: 17 February 2013, At: 04:31 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK

Food Reviews International Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/lfri20 Rice properties and processing Bienvenido O. Juliano a a Cereal Chemistry Department, The International Rice Research Institute, Los Baños, Laguna, Philippines Version of record first published: 03 Nov 2009.

To cite this article: Bienvenido O. Juliano (1985): Rice properties and processing, Food Reviews International, 1:3, 423-445 To link to this article: http://dx.doi.org/10.1080/87559128509540778

PLEASE SCROLL DOWN FOR ARTICLE

Full terms and conditions of use: http://www.tandfonline.com/page/terms-and-conditions This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae, and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand, or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material. Food Reviews International, 1(3), 423-445 (1985-86)

RICE PROPERTIES AND PROCESSING

BIENVENIDO O. JULIANO Cereal Chemistry Department The International Rice Research Institute Los Baños, Laguna, Philippines

RICE PROPERTIES Morphology

Several reviews on rice chemistry and technology have appeared during the last two decades, with emphasis on different aspects of the subject (1-5). The present review deals with rice grain properties and their effects on rice processing. The rice grain (rough rice or paddy) consists of an outer protective covering, the hull, and the rice caryopsis (brown rice or dehulled or husked rice) (Figure 1). Brown rice consists of the outer layers of pericarp, seedcoat, and nucellus, and the germ or embryo, which are maternal tissues, and the endosperm. The endosperm consists of the aleurone layer, with the endosperm proper consisting of the subaleurone layer and the starchy or inner endosperm. The aleurone layer encloses the embryo. The aleurone layer varies from 1 to 5 cell layers, thicker at the dorsal than at the ventral side, and thicker in short-grain than in long-grain rices. The Downloaded by [Tomsk State University of Control Systems and Radio] at 04:32 17 February 2013 aleurone cells are rich in protein bodies (containing globoids or phytate bodies) and in lipid bodies (6). Phytate is mainly the potassium magnesium salt of myo- inosital hexaphosphate.

423

Lemma Palea

Caryopsis

Subaleurone —Pericarp layer _Seedcoat —Nucellus Starchy endosperm ^—Aleurone layer

Embryo

Rachilla Sterile lemmae

Figure 1. Longitudinal structure of the rice grain.

The endosperm cells are thin-walled and packed with amyloplasts containing 3-9 /zni compound starch granules. The two outermost cell layers (the subaleurone layer) are rich in protein and have smaller amyloplasts and compound starch granules. Protein occurs mainly in the form of spherical protein bodies 1-4 fim in size throughout the endosperm (7,8). But crystalline protein bodies and small spherical protein bodies are localized in the subaleurone layer (8). Rice starch granules are polyhedral and mainly 3-9 /xm in size.

Postharvest Technology

Conditions during grain ripening and drying in the field affect the processing characteristics of the rice grain. Evenness of flowering affects the percentage of

Downloaded by [Tomsk State University of Control Systems and Radio] at 04:32 17 February 2013 immatures in the harvest crop, with photosensitive rices having more synchron- ous anthesis than nonsensitive varieties. However, among nonsensitive rices, early-maturing (90-110 days) rices tended to have more immature grains than medium-maturing rices (130-140 days). Immature grains reduce milling quality (9). Dormancy is a desirable trait because it prevents germination of wet grain in the field, but it is a nuisance if the harvested crop is to be immediately used as RICE PROPERTIES AND PROCESSING 425

seed. Dormancy in rice is not true embryo dormancy, because removing the covering hull and bran layers breaks dormancy (10). Storing 3-4 weeks at ambient temperature breaks dormancy, probably due to a temporary barrier to oxygen and water uptake by the embryo (10,11). Stack burning occurs when wet grain, particularly unthreshed grain, is piled without provision for aeration. Microbial respiration causes the mass to heat to over 60°C (12). The resulting milled rice becomes yellow, regardless of variety, due to the heating effect rather than direct microbial infestation, since the yellowing can be simulated even for milled rice in a laboratory oven. Yellowing reduces the lysine content of rice about 10% with a resultant drop in net protein utilization (NPU) in rats (10). Hull tightness is a desirable storage trait of rough rice because a tight hull protects the brown rice from infestation by insects and microorganisms.

Milling and Milling Fractions

Rice is consumed mainly as whole-grain cereal. Rough rice processing consists of dehulling followed by abrasive milling of the brown rice to produce milled or polished or white rice and bran and polish. In the Engelberg or huller- type mills, dehulling and milling are done in one step with greater grain breakage. The by-product is a mixture of hull and bran-polish, which is usually used for animal feed. Modern rice mills produce separate fractions consisting of bran, hull, and milled grain. For modern plants, hull disposal is a problem. An important factor contributing to grain breakage during milling is pre- formed fissures or cracks in brown rice resulting from moisture adsorption stress during drying, storage, and milling (13). Varietal differences in suscep- tibility to fissuring have been demonstrated for both rough rice and brown rice (13,14). Hull tightness would affect the rate of moisture adsorption of rough rice. Immature grains result in small, chalky brokens. Chalky portions in nonwaxy endosperm contribute also to grain breakage (15). Chalky portions correspond to loose arrangement of the cell contents (air spaces) (7). Yellow grains resulting from stack burning are resistant to breakage during milling. Parboiled rice also requires greater pressure to mill because of a harder endosperm. The bran from parboiled rice also tends to clog the sieves (16). Starch is localized mainly in the endosperm of the mature rice grain (Fig- ure 1). Starch is classified based on amylose (linear fraction) content into waxy Downloaded by [Tomsk State University of Control Systems and Radio] at 04:32 17 February 2013 (0-2% amylose) and nonwaxy-low (10-20%), intermediate (20-25%), and high (25-33%) (17). Amylose content is measured by the iodine colorimetry of alkali-dispersed milled rice with iodine-potassium iodide solution in acetate buffer of pH 4.5-4.8 (18). Rice starch granules also differ in final gelatinization temperature (GT), classified as low (<70°C), intermediate (70-74.5°C), and high (75-80°C) (17). Not all combinations of amylose content and GT are r

Table I. Comparative Properties of Rough Rice and Its Fractions at 14% Moisture

Property Rough Rice Brown Rice Milled Rice Rice Bran Rice Hull

Crude protein (% N X 5.95) 5.8-7.7 7.1-8.3 6.3-7.1 11.3-14.9 2.0-2.8 Crude fat (%) 1.5-2.3 1.6-2.8 0.3-0.5 15.0-19.7 0.3-0.8 Crude fiber (%) 7.2-10.4 0.6-1.0 0.2-0.5 7.0-11.4 34.5-45.9 Crude ash (%) 2.9-5.2 1.0-1.5 0.3-0.8 6.6-9.9 13.2-21.0 Available carbohydrates (%) 64-73 73-87 77-89 34-62 22-35 Neutral detergent fiber (%) 16.4 3.9 0.7-2.3 24-29 66-74 Energy content (kJ/g) 15.8 15.2-16.1 14.6-15.6 16.7-19.9 11.1-13.9 Density (g/ml) 1.17-1.23 1.31 1.44-1.46 1.16-1.29 0.67-0.74 Bulk density (g/ml) 0.56-0.64 0.68 0.78-0.85 0.20-0.40 0.10-0.16

Downloaded by [Tomsk State University of Control Systems and Radio] at 04:32 17 February 2013 o RICE PROPERTIES AND PROCESSING 427

known: waxy starch is mainly low GT with some high GT as with low amylose starch. High GT is rare among intermediate- and high-amylose rices. Bran is richer in minerals, vitamins, protein, fat, and fiber than milled rice (5) (Table 1). Bran proteins are rich not only in the lysine-rich proteins albumin (water-soluble) and globulin (salt-soluble), but also in antinutrition factors—trypsin inhibitor and hemagglutinin or lectin, mainly in the embryo. By contrast, milled rice (endosperm) is rich in glutelin (~80% of total), 15% albumin-globulin, and less than 5% prolamin (alcohol-soluble). Crystalline protein bodies are rich in albumin-globulin, whereas spherical protein bodies are rich in prolamin (19). Protein complexed with starch granules not removed by protease or dodecylbenzene sulfonate (0.1-0.7%) is mainly the Wx gene product (20), which is proportionate to amylose content (21). The lipid content is mainly in the bran fraction (20% dry basis) (see Table 1), but about 1.5-1.7% is present in milled rice, mainly as nonstarch lipids extracted by ether, chloroform-methanol, and cold water-saturated butanol (22, 23). Protein bodies, particularly the core, are rich in lipids which are readily extracted (22,24). Starch lipids are mainly monoacyl lipids (fatty acids and lysophosphatides) complexed with amylose (22). The lipid content of starch is lowest for waxy starch granules (about 0.2%) and highest for intermediate- amylose rices (1.0%) and may be slightly lower in high-amylose rice (22,23). Nonstarch lipids are involved in fat rancidity, since amylose protects starch lipids from oxidation (25). Dietary fiber content as indexed by neutral detergent fiber is also higher (about 30%) in bran (26) than in milled rice (0.5- 0.8%) (27) (see Table 1).

Aging and Parboiling

During ambient temperature storage of rough or brown rice, the endosperm undergoes an aging process, particularly during the first 3-4 months after harvest (28,29) (postharvest ripening). The endosperm becomes harder, resulting in better milling recoveries and more flaky cooked rice with less solids in cooking gruel. Parboiling is practiced in India, Pakistan, Sri Lanka, and Bangladesh (where up to 50% of the rice is consumed as milled parboiled rice), probably to accelerate aging of freshly harvested rice (16). Parboiling is also a "salvage" process to upgrade chalky and wet, fermented, discolored paddy, which otherwise Downloaded by [Tomsk State University of Control Systems and Radio] at 04:32 17 February 2013 would produce unacceptably low milling recoveries. The process consists of steeping rough rice to equilibrium water content at a temperature below starch GT, steaming with or without pressure for several minutes with minimum caryopsis expansion, followed by cooling and slow drying (16,30). The endosperm may become discolored, depending on severity of heating, and B 428 JULIANO

vitamins diffuse inward from bran to endosperm. The resultant gelatinization of starch results in a clear, harder endosperm, which resists breakage during milling. However, parboiling results in slightly open hull and destroys antioxidants (16), but inactivates lipoxygenase and other enzymes. In modern parboiling processes using vacuum and steam under pressure, endosperm dis- coloration is minimized. Dry-heat methods may also be used to accelerate aging with the precaution of retaining grain moisture, such as sealed containers, to minimize grain breakage (31,32). Rice is stored mainly as brown rice in Japan but as rough rice in most of tropical Asia. Rubber rollers are used in Japan for dehulling to minimize damage to or bruising of the brown rice surface. Stone dehullers damage the brown rice surface, necessitating immediate milling; otherwise lipase action of bran lipids proceeds readily as in the bran. Within a few weeks milled rice storage results in the loosening of starch granules on the open surface cells, which become powdery. In addition, off-flavors are produced, mainly from oxidation of unsaturated fatty acids on the surface of milled rice, the major carbonyl compound being hexanal (33).

Market Quality

Consumer preference studies and studies of market samples showed a consumer preference and premium for whiteness or well-milled rice with minimum brokens (34,35). Various markets prefer specific sizes and shapes. Fine-grain varieties are preferred in the Philippines and Thailand, whereas shorter-grain javanica or bulu varieties are preferred in Indonesia. Aromatic or scented fine varieties are preferred in India and Pakistan, but small-grain samba varieties are prized in Sri Lanka. Variety name is also sought, relative to cooking and eating qualities. Certain aromatic varieties are prized, such as Khao Dawk Mali 105 in Thailand, Basmati in India and Pakistan, aromatic upland rices in the Phil- ippines, and Rojolele and Seratus Malam in Indonesia, all of which have 2-acetyl-l-pyrroline as the principal aroma compound of cooked rice (36). Pandan (Pandanus amaryllifolius Roxb.) leaves, used to impart aroma to non- aromatic rice during cooking in India and the Philippines, contain 2-acetyl- l-pyrroline (37). Pigmented rices, such as red rice, are common in Sri Lanka and among Downloaded by [Tomsk State University of Control Systems and Radio] at 04:32 17 February 2013 African O. glaberrima rices. RICE PROPERTIES AND PROCESSING 429

Cooking and Eating Qualities

Cooking time is directly affected by GT and by protein content and grain thickness (38,39). Differences in GT were shown to influence the cooking rate constants and enthalpy of cooking (40), particularly at temperatures of 80- 90°C. Rice is cooked either in an optimum amount of water to produce soft- cooked rice (optimum-water method) or in excess water until the core of grain is gelatinized (excess-water method). In the excess-water method, cooking time ranges from 15 to 25 min to achieve 72-75% moisture wet basis. In the optimum-water method, water/rice ratio increases with amylose content, as does volume expansion. Cooked rices differ vastly in texture properties—softness, stickiness, gloss, and whiteness—which are related to the amylose/amylopectin ratio of milled rice (17,38). Waxy rice is very soft, cohesive, tacky, glossy, but darker colored than nonwaxy rice. Waxy rice is the staple food in north and northeast Thailand (Figure 2) and Laos. Low-amylose rice is consumed in most temperate countries producing japonica rice. Intermediate-amylose rice is preferred over high-amylose rice in Indonesia, Thailand, Malaysia, Philippines, Vietnam, and Burma because of its softer texture. High-amylose rices predominate in Bangla- desh, Sri Lanka, India, and Pakistan, except for the intermediate-amylose, aromatic fine rices grown in the Punjab area. Preferred high-amylose varieties have intermediate GT and soft gel consistency and are softer-textured than cooked, hard-gel, high-amylose rices. Unlike in the U.S. market, where low- and medium-grain rices have low amylose and low GT and long-grain rices have intermediate amylose and intermediate GT, the grain size and shape of indica rices are not related to starch type in tropical rices. Waxy rices are preferred for the preparation of sweets and desserts because of their sticky, soft texture and the stability of their starch gel, even when refrigerated.

Nutritional Value

The nutritional value of milled rice is mainly determined by and predicted from the protein content (41,42). Contributing factors are the high lysine content (3.5-4.0%) of rice proteins (although this decreases with an increase in protein content below 10% protein) and the low level of antinutrition factors in milled

Downloaded by [Tomsk State University of Control Systems and Radio] at 04:32 17 February 2013 rice. Although the first limiting essential amino acid of rice protein is lysine, rice diets are probably not limiting in this amino acid, because the other 430 JULIANO

Bangladesh 8 Burma OQ O China

India

Indonesia o • Japan OOP <9r> Korea O O Malaysia, West . . .. Malaysia, East o * Nepal

Pakistan

Philippines QO Sri Lanka

Thailand

Vietnam

Australia

Brazil $% o 000 Egypt

Italy o o odcro o United States o apt U. S. S. R. J I ,, I I I I I I I I ^ *l ^* P |O I I I I I I I I I I 10 15 20 25 30 Milled rice amylose(%dry basis)

Figure 2. Scattergram of amylose content of milled rice from selected rice-producing countries, o, low GT (alkali spreading value 6-7); •, intermediate or high GT (alkali spreading value <6). Source: IRRI, 1978-1983. Downloaded by [Tomsk State University of Control Systems and Radio] at 04:32 17 February 2013 o pi JO

pi Table 2. Comparative Energy and Protein Availability in Brown Rice and Its Milling Fractions (44,45) jo H Property (Wet Basis) Brown Rice Undermilled Rice Milled Rice Bran Polish pi > LSD Z Wt % of Brown Rice 100 95 91 (5%) o JO A. Rat Data o n Energy value (kj/g) 15.9 15.7 15.5 19.9 17.9 0.3 m Digestible energy (kJ/g) 14.9 15.0 15.0 13.4 13.1 Protein content (% N X 6.25) 8.5 8.3 8.1 16.2 12.9 0.2 z Lysine content (g/16 g N) 3.8 3.6 3.6 5.8 5.0 0.1 o True N digestibility8 (% of intake) 96.9b 97.3ab 98.4a 78.8d 82.5c Biological valuea (% of absorbed N) 68.9c 69.7b 67.5c 86.6a 86.3a NPUa(% of intake) 66.7bc 67.8bc 66.4c 68.3b 71.2a

5. Preschool Children Data* Energy absorbed (%) 90.1 ± 1.0b 92.0 ± 1.0a Fat absorbed (%) 94.3 ± 1.8b — 97.6 ± 1.3a — — N absorbed (% of intake) 59.7 ± 8.6a _ 63.3 +3.3a _ N retained (% of intake) 27.3 ± 9.4a 28.9 ± 2.4a

aMeans in the same line followed by a common letter are not significantly different at the 5% level by Duncan's multiple range test (44). Mean ± s.d., 6 children. 200 mg N/kg daily rice-milk diet with 2/3 of dietaiy N from rice (45). Downloaded by [Tomsk State University of Control Systems and Radio] at 04:32 17 February 2013 432 JULIANO

protein sources in the diet—fish, meat, and legumes—are rich in lysine (43). Although brown rice protein has a slightly higher lysine content than milled rice protein, the NPU of both proteins is similar because of the lower digestibility of bran proteins (44,45) (Table 2). Energy digestibility is also about 3% lower in brown rice. Boiling reduces the digestibility of rice protein, in contrast to other cereal proteins, but it improves the biological value of the protein such that NPU in rats is not reduced (46). The poorly digested protein, which passes out of the alimentary system as fecal protein particles, represents the lipid-rich core proteins of the spherical protein bodies, which are poor in lysine but rich in cystine (24). The major nutritional limitation of milled rice is its low protein content. Efforts to breed rice two percentage points higher in protein have not been successful due to poor heritability of endosperm protein content. However, early-maturing rices (90-110 days) tend to have higher grain protein content than medium-maturity rices (47).

PROCESSED RICE PRODUCTS Introduction

Milled rice for food applications is preferably well milled and freshly milled to ensure low fat content and minimal fat rancidity. The flavor of cooked rice has been attributed to hydrogen sulfide, ammonia, and ethanal (48). Its level decreases during milled-rice aging (49). The level of sulfur volatiles, particularly hydrogen sulfide and dimethyl sulfide, also decreases during storage (50). Dimethyl sulfide is the off-flavor compound in rice wine (sake) prepared from rice stored above 15°C (51).

Parboiled Rice

Parboiled milled rice is preferred to raw milled rice as the staple food in Bangla- desh and Sri Lanka and by 50% of rice consumers in India and Pakistan. Par- boiled rice is also the starting material for canned and quick-cooking rices in the United States and for traditional puffed rice products, discussed in later

Downloaded by [Tomsk State University of Control Systems and Radio] at 04:32 17 February 2013 sections of this review. Although parboiled milled rice takes longer to cook, cooking time may be reduced by presoaking of the rice before cooking. Parboiled rice has a distinctly different taste from that of raw rice. The cooked parboiled rice also does not disintegrate on overcooking in contrast to cooked raw rice, but is firmer. Parboiled rice is no more prone to oxidative rancidity than raw rice, probably RICE PROPERTIES AND PROCESSING 433

because of the inactivation of lipoxygenase and antioxidants during parboiling (16).

Precooked, Quick-Cooking, and Convenience Rice Foods Precooked and Quick-Cooking Rice Quick-cooking rices have been reviewed (52-54). Quick-cooking rices require significantly less cooking time than raw rice (raw milled rice requires 15-25 min and raw brown rice, 45-60 min). Parboiled rice requires a much longer time. The grain is precooked in boiling water, steam, or both, and usually dried in such a way that a porous and open-structured condition, without clumping, is retained (52,54). An exception is the dry-heat treatment, where the grain fissures but the starch granules are not gelatinized. Easy-to-cook brown rice in Japan is prepared by drying brown rice in a countercurrent hot-air stream at 105-130°C for 10-30 min and quickly cooling below 30°C, which makes it cook as fast as milled rice and allows it to be cooked together with milled rice (54). "Cream of rice" is raw milled rice grits from low-GT, low-amylose rice and cooks quicker because of smaller particle size.

Canned Rice The desired canned rice product in the U. S. is white, with separate noncohesive grains, a minimum amount of longitudinal splitting and fraying of edges and ends, and a clear canning liquor (55). Because of the required cooked rice stability, intermediate-amylose rices are used in canned rice. The grain is usually parboiled before canning to produce the desired stability. Cross-linking also improves grain stability, but chemicals used are not approved for food applications. A pH below 4.6 is suggested for canned rice to reduce microbial contamination, because retorted canned rice may not be completely sterilized. In Japan, low-amylose milled rice with water or broth or other seasoning is placed in tin cans, steamed for about 30 min, and sealed and sterilized in a retort at 112°C for 80 min (54). Canned rice is placed in boiling water for 15 min before serving. Seasoned canned rice is marketed primarily as military rations and as emergency foods. Intermediate-amylose rice is also used in

Downloaded by [Tomsk State University of Control Systems and Radio] at 04:32 17 February 2013 canned rice for the military in the Philippines.

Infant Foods Production of precooked infant rice cereal consists of preparing and cooking a cereal slurry, which is then dried in a double-drum atmospheric drier, flaked, 434 JULIANO

and packaged (56). Many of the problems associated with the production of infant rice cereal can be traced to the starch fraction. Hydrated precooked and ready-to-eat baby foods must have the right consistency—soft enough to be swallowed easily but thick enough to feed without spilling. Malt and fungal a-amylase may be added to control the quantity of liquid required to re- constitute the dried cereal by partial hydrolysis of the starch. Rice grits are also used in baby foods to adjust the consistency (57). Low- amylose rices give stable gels and are very efficient stabilizers, unlike intermediate-amylose rices which show syneresis or separation of rigid gel and liquid. Rice flour is not a suitable stabilizer for acid products at pH 4.3 or lower, because of severe thinning due to acid hydrolysis during processing. Free fatty acids protect the starch amylose from liquefaction.

Convenience Rice Foods Precooked rice is used for rice-based convenience food products, wherein non- rice ingredients are packed separately and mixed only during heating. Wild rice (Zizania aquatica) mixed with milled rice is popular in the U.S. Wild rice is not an Oryza species and is closer to oats. Its characteristic flavor is enhanced by curing (short-term wet storage) with active fermentation followed by parch- ing (drying from 35-50% moisture to 7-12% with gelatinization) (58). Retort rice in Japan is made by hermetically sealing cooked nonwaxy and waxy rice in laminated plastic or aluminum-laminated plastic pouches, and pasteurizing at 120°C (54). Steamed waxy rice with red beans accounts for 80% of retort rice in Japan. An aluminum-laminated plastic film pouch is wanned directly in hot water for 10-15 min, whereas plastic pouches may be punctured and heated in a microwave oven for 1-2 min.

Expanded Rice Products Popped and Puffed Rices Popped and puffed rice are traditional breakfast cereals and snack foods (54, 59). In India, Nepal, and Japan, raw rice is traditionally popped by heating rough rice (13-17% moisture) at about 240°C within 30-35 sec, 275°C for 40-45 sec, or in an oil bath at 215-230°C (54,59,60). The hull contributes to

Downloaded by [Tomsk State University of Control Systems and Radio] at 04:32 17 February 2013 pressure retention before popping, because brown rice produces a lower popping percentage than rough rice. Good popping varieties have a tight hull, significant clearance between hull and brown rice, and, freshly harvested, are free of grain fissures. Although waxy rices give high volume expansion, three Nepalese varieties used for popped rice also have high amylose and intermediate GT(61). RICE PROPERTIES AND PROCESSING 435

Puffed- and flaked-rice products are popular snack foods (54). The process consists of steeping rough rice in cold or warm water, toasting the steeped grain, usually in hot sand, at about 250°C to parboil for 40-60 sec, tempering for a few minutes, and flattening with either a wooden mortar and pestle or an edge-runner (62). Nonwaxy rice is used in India and Bangladesh, but waxy rice is used in the Philippines (63). Flaked or beaten rice (brown rice) and parboiled milled rice may be con- verted to puffed rice by heating in hot air or roasting in hot sand (54). With normal parboiled milled rice, puffed volume was directly proportional to severity of parboiling (equilibrium water content of steeped grain) and was highest for waxy rice (64). However, with increasing temperature and period of roasting rough rice, high-amylose rice (specifically 27%) gave the maximum puffed volume on roasting of beaten rice (65). Presumably the minimal retrogradation of parboiled starch in sand roasting allowed the expansion of nonwaxy starch in contrast to normal parboiled rice.

Dry Breakfast Cereals and Snack Foods

In the U.S., dry rice breakfast cereals include rice flakes, oven-, gun-, or extruder-puffed rice, shredded-rice cereal, and multigrain cereals (56). They are of the ready-to-eat type, where rice starch has texture-modifying properties and rice also imparts its own special flavor. Among the important properties is "bowl life," or the ability to retain its texture and crispness in milk while being eaten. Moisture-proof packaging is critical for optimum shelf life. While low-amylose, low-GT rices are used for breakfast cereals in the U.S., intermediate- and high-amylose rices are used in the Philippines, provided the degree of cooking is similarly controlled to obtain an acceptable puffed volume from the grain (54). Gun puffing of raw milled rice preheated with steam has been duplicated by extrusion cooking (54). Aged rice is preferred. Molded, caramelized, puffed nonwaxy and waxy rice is a common snack in the Philippines. Okoshi is a typical Japanese rice cake made of puffed broken rice mixed and molded with millet jelly, sugar, and flavoring (54). "Puffrice Cracker" uses brown rice, mainly immature grains, moistened to about 30%, passed through an extruder where it is cooked 10 sec at 100°C, and extruded as a sheet at a die temperature of 140°C (54). The sheet is then cut into plate-size pieces, dried, and

Downloaded by [Tomsk State University of Control Systems and Radio] at 04:32 17 February 2013 packed.

Extrusion-Cooked Products Extrusion cooking has been used in preparing snack foods. It is also used to prepare precooked, rice-based baby foods, because the extruded product does 436 JULIANO

not require much additional drying before packaging (54). However, optimum conditions for extrusion cooking differ among extruders and are affected by the particle size of dry-milled flour, moisture content of batter, and extrusion temperature and pressure. Starch granules are completely gelatinized, but spherical protein bodies in the protein masses maintain their structure (66). For flours extruded at 15% moisture at 150°C, some (11-13%) decrease in lysine content is noted which corresponds to 3-5% lower true protein digestibility and biological value, and 7-8% lower NPU in growing rats (67). The viscosity in water and 0.2 N KOH dropped drastically. Mung bean and milk showed a greater decrease in lysine content during extrusion cooking with rice to the extent that the lysine content dropped from 6.1 to 3.3 g/16 g N for a rice-mung bean-milk formulation (67).

Rice Dishes, Breads, and Cakes Rice Dishes and Puddings Specific rice types are used for various rice dishes. Waxy rices are commonly used for sweets and desserts. Low-amylose rices are used for Spanish paella and Italian risotto because of the cohesive nature of the cooked rice. Low-amylose, short-grain rice is used in preparing rice pudding in the U.S., Europe, China, etc. (68). The rice is cooked in boiling water, strained, and mixed with milk before the completion of cooking. Egg yolks, sugar, vanilla, and light cream are added together with a variety of fruit combinations. The Japanese rice pudding uiro consists of waxy rice flour, corn starch, sugar, water, and flavoring mixed and steamed for 60 min at 100°C with sweet bean curd, green tea, coffee, cherries, and other fruits (54).

Rice Breads A 100% rice-flour, yeast-leavened bread has been successfully developed consisting of 100 parts rice flour, 75 parts water, 7.5 parts sugar, 6 parts oil, 3 parts fresh compressed yeast, 3 parts hydroxypropyl methylcellulose, and 2 parts salt (69). Although all nonwaxy rices produce breads of equivalent ap- pearance, only low-amylose, low-GT rices gave soft-texture bread crumb. Inter- mediate-amylose, intermediate-GT rices gave sandy, dry-crumb characteristics.

Downloaded by [Tomsk State University of Control Systems and Radio] at 04:32 17 February 2013 However, among low-GT rices, low-amylose rice gave lower loaf volume than intermediate- and high-amylose rices (7). Wet-milled flour gave improved texture over dry-milled flour. Rice flour, in addition to sorghum (54), has also been used in making Pakistani bread similar to roti, the flat unleavened bread commonly made from RICE PROPERTIES AND PROCESSING 437

wheat flour. The desired bread similar to wheat chapatti is puffed, semilight, flexible, uniformly round and firm, but not rough. Red rices, such as Dwarf Red Gunja, are preferred in some villages in Sind Pakistan for rice bread. IRRI6 (IR6-159-2 or Mehran 69) also produced better bread than IR8, which remains soft longer. Rice flour may be added in a proportion of up to 15% to wheat flour. The addition of 21% rice in chapatti results in still acceptable but difficult-to-slice bread.

Rice Cakes

An all-rice-flour layer cake formula consists of 100 parts rice flour, 80 parts sugar, 80 parts water, 15 parts oil, and 5-7 parts double-acting baking powder (69). Again, flours from low-amylose, low-GT rices are preferred for the formula; intermediate-amylose, intermediate-GT rices gave sandy, dry texture. Because a high level of sugar markedly increases GT, low-GT rices in 50% sucrose had 80°C GT, but intermediate-GT rices had 92°C GT. Even when sucrose level was reduced to have 80°C GT for the intermediate-GT rice, volume and contour of the cakes improved but sandy texture remained. Hydrating the rice flour by intense mixing of the flour and water and holding of the hydrated mixture improved the texture and volume of the cake. Baked Japanese cakes include senbei and arare (54,68). Senbei is a cracker- like snack made of nonwaxy rice flour baked at 200-260°C. Arare is cracker made from waxy rice. Arare expands more during baking, produces a soft texture, and can be easily dissolved in the mouth. Senbei is harder and rougher. Dryland rices give lower expanded volume of arare than wetland rices (71). Similar dry cakes are traditionally prepared in the Philippines {puto seko) and in China (xianggao). Janapese rice cake or paste (mochi) is traditionally prepared from waxy milled rice by washing, steaming at 100°C for about 15 min to a 40% moisture content, grinding (kneading or mortar and pestle), packing in plastic film, pasteurizing 20 min at 80°C, and cooling (54). Recently, gelatinized waxy rice flour has been manufactured directly by extrusion cooking and has multi- purpose applications including mochi. Mochi is usually cut into pieces, toasted, and seasoned with soy sauce or wrapped in dried laver, and eaten as a snack. Preferred waxy rices have a starch final GT of 66-69°C (72,73). Wet-milled waxy or nonwaxy rice flour may be kneaded with water and con- verted to sweetened rice cake (nenkau in China or puto in the Philippines) Downloaded by [Tomsk State University of Control Systems and Radio] at 04:32 17 February 2013 by adding sugar and other ingredients before steaming (54). A yeast-fermented rice cake is produced in the Philippines for which aged, intermediate-amylose rice yielded the greatest volume expansion and optimum softness of steamed cake (74). Overnight fermentation provides carbon dioxide and flavor. 438 JULIANO

Rice Flours and Starch Rice Flours Dry-milled, waxy and nonwaxy rice flours are available in Japan and other countries together with pregelatinized flours (54,69). Wet-milled rice flour usually produces a finer textured product than dry-milled rice flour, such as in rice cakes and desserts and sweets, because of the reduction of milled rice into discrete starch granules 3-9 jum in size, with damaged starch removed during filtration or centrifugation. The white bran produced from the overmilling of nonwaxy milled rice for sake manufacture is relatively rich in protein and suitable for the preparation of infant food (75).

Rice Starch Rice starch production involves mainly wet milling of broken rice with 0.3- 0.5% NaOH to remove protein (76). Steeping of brokens in an alkali solution for 24 hr is followed by wet milling in pin mills, hammermills, or stone-mill disintegrators with the alkali solution. After storing the batter for 10-24 hr, fiber is removed by passing through screens and the starch is collected by centrifugation, washed with water, and dried. Protein in the effluent is recovered by neutralization and used as an animal feed supplement. In the EEC, about 8,800 t of broken rice is processed to about 7,000 t starch in 5-6 plants in four countries: Belgium, Germany, Italy, and the Netherlands (77). Rice starch is used exclusively in the human food section, largely for baby food. Egypt and Syria also produce rice starch, but Japan and the U.S. are no longer in production because of the prohibitive cost of rice.

Rice Noodles

Rice noodle (Chinese meiri) is the principal form of processed rice product consumed in Southeast Asia. It is served during birthdays and anniversaries to symbolize long life (54). Noodles may be fried, mixed with meat, or used in soups. Noodles prepared from cereals without gluten, such as rice, require some gelatinized starch to act as a binder in place of gluten. They may either be

Downloaded by [Tomsk State University of Control Systems and Radio] at 04:32 17 February 2013 extruded or sheeted. Traditionally, extruded noodles (bihon, bijon, bifun, or vermicelli) are prepared from high-amylose milled rice or brokens by wet milling steeped milled rice, kneading into balls, surface-gelatinizing kneaded flour balls in boiling water bath, remixing, extruding through hydraulic press with die, subjecting extruded noodles to heat treatment for surface gelatinization, soaking in cold RICE PROPERTIES AND PROCESSING 439

water, and drying in racks (54). Freshly milled rice is preferred to minimize lipid rancidity. Although extruded noodles are not gelatinized in Western processes, boiling the extruded noodles improves the boiling-water stability of the noodles. The rice undergoes considerable starch degradation during processing as indexed by gel consistency and viscosity (75). The hard gel consistency of high-amylose rices is preferred for extruded noodles for maximum stability of noodles in boiling water. Low-amylose local rices cannot replace imported high-amylose rice for extruded noodles in Japan (54). Rice grits (dry-milled) and wet-milled flour are starting materials for the preparation of sheeted or flat noodles (54). The traditional Thai process uses wet-milled flour batter placed in a noodle-making machine consisting of a trough with a smooth sealed horizontal drum dipping up to halfway in the rice batter. The smooth drum is then slowly rotated, and the adhering milk layer is scraped by a stainless steel sheet at a 45° angle and allowed to flow onto a taut cotton conveyor into a steam tunnel for gelatinization. The gelatinized sheet (about 1 mm thick) then passes through driers via conveyor belts and through a cutter. The partially dried plates are placed on frames to be further dried and cut into noodle strips with a paper cutter before final drying. The rice undergoes very minimal shear in the process and maintains its gel viscosity. Low-amylose, dry-milled Japanese rice grits with a 100- 150 Mm fraction gave satisfactory sheeted Japanese noodles (79), which are sold at 33-40% moisture just like wheat noodle or udon.

Fermented Rice Foods

Idli (rice pudding) and dosai (rice cake) are prepared in India from a mixture of rice and black gram (Phaseolus mungo), about 3:1 by weight, typically as a breakfast food. Parboiled milled rice and decorticated black gram are washed, soaked 5-10 hr in 1.5-2.2 times by weight of water, and wet-milled separately to give coarse (0.6 mm) rice flour and smooth gelatinous gram paste (80). The flours are mixed together with 0.8% salt, and the thick batter is fermented overnight, steamed, and served hot. Ingredients added to idli for flavor are cashew nut, ghee, pepper, ginger, sour buttermilk, and yeast. Dosai usually contains less black gram and is usually fried, not steamed. Batter quality of idli is attributed to the globulin protein and the arabinogalactan of black gram (81). The globulin helps in raising the dough, but arabinogalactan stabilizes the Downloaded by [Tomsk State University of Control Systems and Radio] at 04:32 17 February 2013 foam network even at steaming temperatures, contributing to the porosity of the steamed idli. Parboiled high-amylose rices are suitable for idli. The rice batter probably contributes also to gas retention as in fermented rice cake. Other fermented rice products are Sierra rice (amarillo or requemado) from Latin America, angkak (anka, red rice), and waxy rice wines (80,82,83). 440 JULIANO

Sierra rice is derived from moist rough rice fermented by the microorganisms with which it is contaminated, with heating up to 50-70°C. The grain becomes yellow to brown, and the grain is precooked and predigested. Angkak may be produced by Monascus purpureus mold on cooked rice at 35% moisture, pH 6.5, at room temperature (84), and is used as a coloring agent for food such as fermented fish (80).

Rice Wines and Beer Adjunct Rice Wines Various fermented, waxy rice wines are prepared by fermenting steamed waxy milled rice with fungi and yeast starter (80,82,83,85). A sweet product is produced first, which then becomes alcoholic as fermentation progresses. The liquid is removed by decantation. Examples are Chinese lao-chao, Thai khaomak, Indonesian tape ketan, and Philippine tapuy. Indian shonti annam uses cooked nonwaxy rice. Starters are readily available in the market. Rice is the sole cereal source in rice wine such as sake (75). The raw material is highly milled rice (to remove 25-30% by weight of brown rice) with a low amylose and low GT and with a white core for ease of swelling, cooking, and penetration by mycelia of Aspergillus oryzae. Overmilling results in lower (5-6%) protein content and only 0.1% nonstarch lipids and 0.7% fat- by-hydrolysis (starch lipids) and lower K and P content. Steamed rice is inocu- lated with koji, a culture of Aspergillus oryzae grown on steam rice and seed mash. Sake yeast is grown on koji and steamed rice containing 70 ml lactic acid/100 liter water at 12°C. Three more additions of materials are made to maintain fermentation. Sugars liberated by A. oryzae enzymes from rice are fermented by yeast and the level of sugars regulates the rate of fermentation by yeast. An ethanol content of up to 20% is tolerated by the sake yeast. After fermentation, ethanol is added to adjust the final ethanol level to 20-22%. The mash is filtered, clarified, pasteurized, and matured or aged for 3-8 months. It is then blended, adjusted to 15-16% ethanol content, filtered through activated carbon, bottled, and pasteurized. Steaming denatures rice protein (24), making it resistant to the action of acid proteases. One of the main flavor components of sake is isoamyl acetate (86). Isoamyl alcohol may be derived by assimilation and metabolism by yeast of leucine from rice protein hydrolysis, followed by acetic acid esterifica- Downloaded by [Tomsk State University of Control Systems and Radio] at 04:32 17 February 2013 tion. Recent developments in sake production are the use of lipase during steeping of rice and dehydration of steamed rice with ethanol (both of which reduce lipid content), the use of raw rice, and the use of saccharified rice bran. Treating rice with the insecticide methyl bromide results in methylation of rice proteins. In. sake mash fermentation, these proteins are decomposed to RICE PROPERTIES AND PROCESSING 441

form methyl methionine, which divides spontaneously into homoserine and dimethyl sulfide while sake is aged (87). Dimethyl sulfide gives an off-flavor to sake.

Beer Adjunct Broken rice, together with corn grits, is an adjunct in beer manufacture (75). Rice is preferable because of its lower protein and lipid content (<1.5%). Broken rice is obtained from regular milling of brown rice in most countries except in Japan, where broken rice is milled from broken brown rice (rice is stored as brown rice in Japan). Broken rice must be free of bran contamination. Low-GT, low-amylose rices are used because intermediate-GT, intermediate- amylose rices are relatively resistant to starch liquefaction. Complete liquefaction is critical, and faster gelatinized low-GT starch of low amylose content is probably hydrolyzed much faster by malt enzymes during mashing. The starch can be gelatinized at temperatures below 70°C and requires less cooling before malt addition. Enzymes are rapidly inactivated at 70°C. A summary of the food and beverages prepared from rice and the usual or preferred amylose type of milled rice for each product is given in Table 3.

Table 3. Rice Food and Beverage Products Prepared from Milled Rice and the Various Amylose Types Usually Used for Their Processing

Nonwaxy Amylose Type

Product Waxy Low Intermediate High

Rice noodles, extruded + Rice noodles, sheeted + + Parboiled rice + + + Quick-cooking rices + + + + Canned rice + + + Desserts and sweets + + Puddings and frozen sauces + + Infant foods + + Dry breakfast cereals + + Popped rice + + Puffed rices + + + Rice cakes +a +a + Downloaded by [Tomsk State University of Control Systems and Radio] at 04:32 17 February 2013 Rice crackers + + + Rice breads +a + Rice wines + + Beer adjunct +a aLow GT desirable. 442 JULIANO

Environmental factors, particularly temperature during ripening, probably affect grain starch properties. High temperature independently decreases amylose content and increases starch GT, while low temperature increases amylose content and decreases starch GT (88-90).

SUMMARY

Milled rice consists of 90% starch, 8% protein, and less than 1% each crude ash, crude fiber, and crude fat. Factors affecting milling quality are variety, maturity, dormancy, fissured and chalky grains, stack burning, aging, and parboiling. Starch properties affecting cooking and eating quality are amylose content and, within the same amylose class, starch final gelatinization temperature and gel consistency. Nutritional value of milled rice is determined by protein content because of its high lysine content and the absence of antinutrition factors. Fresh, highly milled rice is preferred in processed rice products to minimize nonstarch, lipid oxidative and hydrolytic rancidity. Varietal differences in starch properties and cooked rice texture are taken advantage of in preparing quick-cooking rice, cooked rice, popped and puffed rices, rice noodles, infant, breakfast, and snack foods, cakes, pudding and breads, and fermented rice foods and beverages.

REFERENCES

1. D. F. Houston, Ed., "Rice Chemistry and Technology," Am. Assoc. Cereal Chemists, St. Paul, Minn., 1972. 2. E. V. Araullo, D. B. de Padua, and M. Graham, Eds., "Rice Postharvest Technology," Int. Dev. Res. Cent., Ottawa, 1976. 3. International Rice Research Institute, "Proceedings of a Workshop on Chemical Aspects of Rice Grain Quality," Los Baños, Laguna, Philippines, 1979. 4. B. S. Luh, Ed., "Rice Production and Utilization," AVI, Westport, Conn., 1980. 5. B. O. Juliano, Ed., "Rice Chemistry and Technology," rev. ed., Am. Assoc. Cereal Chemists, St. Paul, Minn., 1985. 6. K. Tanaka, T. Yoshida, K. Asada, and Z. Kasai, Arch. Biochem. Biophys., 155, 136 (1973). 7. A. R. del Rosario, V. P. Briones, A. J. Vidal, and B. O. Juliano, Cereal Chem., 45, 225 (1968). Downloaded by [Tomsk State University of Control Systems and Radio] at 04:32 17 February 2013 8. D. B. Bechtel and Y. Pomeranz, Am. J. Bot., 64, 966 (1977). 9. Y. M. Indudhara Swamy and K. R. Bhattacharya, J. Food Proc. Eng., 3, 29 (1979). 10. E. P. Navasero, L. C. Baun, and B. O. Juliano, Phytochem., 14, 1899 (1975). 11. G. A. Martires, Ph.D. dissertation, Univ. Santo Tomas, Manila, 1975. 12. B. O. Eggum, B. O. Juliano, C. P. Villareal, and C. M. Perez, Qual. Plant. Plant Foods Hum. Nutr., 34, 261 (1984). RICE PROPERTIES AND PROCESSING 443

13. O. R. Kunze and C. W. Hall, Trans. Am. Soc. Agric. Engr., 21, 361 (1965). 14. T. Srinivas, M. K. Bhashyam, M. K. Mune Gowda, and H. S. R. Desikachar, Indian J. Agric. Sci., 48, 424 (1978). 15. Y. M. Indudhara Swamy and K. R. Bhattacharya, J. Food Sci. Technol., 19, 125 (1982). 16. K. R. Bhattacharya, in "Rice Chemistry and Technology," revised ed., B. O. Juliano, Ed., Am. Assoc. Cereal Chemist, St. Paul, Minn., 1985. 17. B. O. Juliano, in "Proceedings of a Workshop on Chemical Aspects of Rice Grain Quality," International Rice Research Institute, Los Baños, Laguna, Philippines, 1979, p. 69. 18. B. O. Juliano, C. M. Perez, A. B. Blakeney, D. T. Castillo, N. Kongseree, B. Laignelet, E. T. Lapis, V. V. S. Murty, C. M. Paule, and B. D. Webb, Starke, 33, 157 (1981). 19. K. Tanaka, T. Sugimoto, M. Ogawa, and Z. Kasai, Agric. Biol. Chem., 44, 1633 (1980). 20. Y. Sano, Theoret. Appl. Genet., 68, 467 (1984). 21. International Rice Research Institute, "Annual Report for 1984," Los Baños, Laguna, Philippines, 1985. 22. N. H. Choudhury and B. O. Juliano, Phytochem., 19, 1385 (1980). 23. B. O. Juliano and M. S. Goddard, Qual. Plant. Plant Foods Hum. Nutr. (in press). 24. Y. Tanaka, A. P. Resurreccion, B. O. Juliano, and D. B. Bechtel, Agric. Biol. Chem., 42, 2015(1978). 25. W. R. Morrison, J. Sci. Food Agric., 29, 365 (1978). 26. C. C. Maniñgat and B. O. Juliano, Phytochem., 21, 2509 (1982). 27. C. G. Pascual and B. O. Juliano, Phytochem., 22, 151 (1983). 28. R. M. Villareal, A. P. Resurreccion, L. B. Suzuki, and B. O. Juliano, Starke, 28, 88 (1976). 29. C. M. Perez and B. O. Juliano, in "Documentation of the GASCA Seminar Paddy Deterioration in the Humid Tropics," Baguio, 1981, German Agency for Technical Cooperation (GTZ), Eschborn, Germany, 1982, p. 180. 30. S. N. Raghavendra Rao and B. O. Juliano, J. Agric. Food Chem., 18, 289 (1970). 31. K. R. Bhattacharya, H. S. R. Desikachar, and V. Subrahmanyan, Indian J. Technol., 2, 378 (1964). 32. F. L. Normand, J. T. Hogan, and H. J. Deobald, Rice J., 67(13), 7 (1964). 33. T. Tsugita, T. Ohta, and H. Kato, Agric. Biol. Chem., 47, 543 (1983). 34. A. M. del Mundo and B. O. Juliano, J. Texture Stud., 12, 107 (1981). 35. L. J. Unnevehr, B. O. Juliano, and C. M. Perez, International Rice Research Institute (Los Baños, Laguna, Philippines), Res. Paper Ser. No. 116 (1985), 20 pp. 36. R. G. Buttery, L. C. Ling, B. O. Juliano, and J. G. Turnbaugh, J. Agric. Food Chem., 31, 823 (1983). 37. R. G. Buttery, B. O. Juliano, and L. C. Ling, Chem. Ind. London, 478 (1983). 38. B. O. Juliano, L. U. Oñate, and A. M. del Mundo, Food Technol., 19, 1006 (1965). 39. B. O. Juliano and C. M. Perez, J. Texture Stud., 14, 235 (1983). 40. B. O. Juliano and C. M. Perez, Food Chem. (accepted for publication). 41. W. C. MacLean, Jr., G. L. Klein, G. Lopez de Romaña, E. Massa, and G. G. Graham, J. Nutr., 108, 1740 (1978). Downloaded by [Tomsk State University of Control Systems and Radio] at 04:32 17 February 2013 42. B. V. Roxas, C. LI. Intengan, and B. O. Juliano, J. Nutr., 109, 832 (1979). 43. M. Autret, J. Périssé, F. Sizaret, and M. Cresta, Nutr. Newslett. FAO, 6(4), 1 (1968). 44. B. O. Eggum, B. O. Juliano, and C. C. Maniñgat, Qual. Plant. Plant Foods Hum. Nutr., 32, 371 (1982). 45. M. I. C. Santiago, B. V. Roxas, C. LI. Intengan, and B. O. Juliano, Qual. Plant. Plant Foods Hum. Nutr., 34, 15 (1984). 444 JULIANO

46. B. O. Eggum, A. P. Resurreccion, and B. O. Juliano, Nutr. Rep. Int., 16, 649 (1977). 47. International Rice Research Institute, "Annual Report for 1983," Los Baños, Laguna, Philippines, 1984, p. 69. 48. Y. Obata and H. Tanaka, Agric. Biol. Chem., 29, 191 (1965). 49. S. Moritaka and K. Yasumatsu, Eiyo To Shokuryo, 25, 59 (1972). 50. S. Sato, M. Tadenuma, T. Oba, Y. Takahashi, and K. Koike, Nippon Jozo Kyokai Zasshi, 71, 387 (1976). 51. K. Takahashi, T. Ohba, M. Takagi, S. Sato, and Y. Namba, Hakko Kogaku Zasshi, 57, 148 (1979). 52. R. L. Roberts, in "Rice Chemistry and Technology," D. F. Houston, Ed., Am. Assoc. Cereal Chemists, St. Paul, Minn., 1972, p. 381. 53. B. S. Luh, R. L. Roberts, and C.-F. Li, in "Rice: Production and Utilization," B. S. Luh, Ed., AVI, Westport, Conn., 1980, p. 566. 54. B. O. Juliano and J. Sakurai, in "Rice Chemistry and Technology," revised ed., B. O. Juliano, Ed., Am. Assoc. Cereal Chemists, St. Paul, Minn., 1985. 55. E. E. Burns and D. L. Gerdes, in "Rice Chemistry and Technology," revised ed., B. O. Juliano, Ed., Am. Assoc. Cereal Chemists, St. Paul, Minn., 1985. 56. S. F. Brockington and V. J. Kelly, in "Rice Chemistry and Technology," D. F. Houston, Ed., Am. Assoc. Cereal Chemists, St. Paul, Minn., 1972, p. 400. 57. V. J. Kelly, in "Rice Chemistry and Technology," B. O. Juliano, Ed., Am. Assoc. Cereal Chemists, St. Paul, Minn., 1985. 58. D. B. Lund, R. C. Lindsay, D. A. Stuiber, C. E. Johnson, and E. H. Marth, Cereal Foods World, 20, 150 (1975). 59. T. Srinivas and H. S. R. Desikachar, J. Sci. Food Agric., 24, 883 (1973). 60. International Rice Research Institute, in "Annual Report for 1975," Los Bafios, Laguna, Philippines, 1976, p. 83. 61. International Rice Research Institute, in "Annual Report for 1983," Los Baños, Laguna, Philippines, 1984, p. 21. 62. R. Shankara, T. K. Ananthachar, H. V. Narasimha, H. Krishnamurthy, and H. S. R. Desikachar, J. Food Sci. Technol., 21, 121 (1984). 63. A. A. Antonio and B. O. Juliano, Philipp. Agric., 58, 17 (1974). 64. A. A. Antonio and B. O. Juliano, J. Food Sci., 38, 915 (1973). 65. R. Chinnaswamy and K. R. Bhattacharya, J. Cereal Sci., 2, 273 (1984). 66. M. B. de Mosqueda, C. M. Perez, R. R. del Rosario, B. O. Juliano, and D. B. Bechtel, Food Chem., 19 (in press, 1986). 67. B. O. Eggum, B. O. Juliano, M. G. B. Ibabao, and C. M. Perez, Food Chem., 19 (in press, 1986). 68. C.-F. Li and B. S. Luh, in "Rice: Production and Utilization," B. S. Luh, Ed., AVI, Westport, Conn., 1980, p. 690. 69. M. M. Bean and K. D. Nishita, in "Rice Chemistry and Technology," revised ed., B. O. Juliano, Ed., Am. Assoc. Cereal Chemists, St. Paul, Minn, 1985. 70. International Rice Research Institute, in "Annual Report for 1975," Los Baños, Laguna, Philippines, 1976, p. 83. 71. H. Yanase, I. Endo, N. Shibuya, and K. Ohtsubo, Shokury o Kenkyusho Kenkyu Downloaded by [Tomsk State University of Control Systems and Radio] at 04:32 17 February 2013 Hokoku, 41, 39 (1982). 72. E. P. Palmiano and B. O. Juliano, Agric. Biol. Chem., 36, 157 (1972). 73. H. Yanase, I. Endo, and S. Chikubu, Shokuryo Kenkyusho Kenkyu Hokoku, 40, 8 (1982). 74. A. A. Perdon and B. O. Juliano, Stärke, 27, 196 (1975). RICE PROPERTIES AND PROCESSING 445

75. K. Yoshizawa and S. Kishi, in "Rice Chemistry and Technology," revised ed., B. O. Juliano, Ed., Am. Assoc. Cereal Chemists, St. Paul, Minn., 1985. 76. B. O. Juliano, in "Starch Chemistry and Technology," 2nd ed., R. L. Whistler, J. N. BeMiller, and E. F. Paschall, Eds., Academic Press, Orlando, 1984, p. 507. 77. W. Kempf, Stärke, 36, 333 (1984). 78. A. K. Khandker, M. B. de Mosqueda, R. R. del Rosario, and B. O. Juliano, ASEAN Food J. (submitted for publication). 79. S. Saito, Denpun Kagaku, 27, 295 (1980). 80. C. W. Hesseltine, J. Am. Oil Chemists' Soc., 56, 367 (1979). 81. N. S. Susheelamma and M. V. L. Rao, J. Food Sci., 44, 1309 (1979). 82. A. G. van Veen, in "Rice Chemistry and Technology," D. F. Houston, Ed., Am. Assoc. Cereal Chemists, St. Paul, Minn., 1972, p. 428. 83. H.-H. Wang, in "Rice: Production and Utilization," B. S. Luh, Ed., AVI, Westport, Conn., 1980, p. 650. 84. E. I. Dizon and P. C. Sanchez, Philipp. Agric., 67, 25 (1984). 85. S. Saono, F. G. Winarno, and D. Kardjati, Eds., "Proc. Techn. Seminar, Traditional Food Fermentation as Industrial Resources in ASCA Countries," Medan, Indonesia, 1981, Indonesian Inst. Sci., Jakarta, 1982. 86. T. Ishikawa and K. Yoshizawa, Agric. Biol. Chem., 43, 45 (1979). 87. K. Kitamoto, T. Ohba, and Y. Namba, Agric. Biol. Chem., 45, 1713 (1981). 88. Z. Nikuni, S. Hizukuri, K. Kumagai, H. Hasegawa, T. Moriwaki, T. Fukui, K. Doi, S. Nara, and L. Maeda, Mem. Inst. Sci. Ind. Res. Osaka Univ., 26, 1 (1969). 89. A. P. Resurreccion, T. Hara, B. O. Juliano, and S. Yoshida, Soil Sci. Plant Nutr., 23, 109 (1977). 90. M. Asaoka, K. Okuno, Y. Sugimoto, J. Kawakami, and H. Fuwa, Stärke, 36, 189 (1984). Downloaded by [Tomsk State University of Control Systems and Radio] at 04:32 17 February 2013