Ghoneum M, Jewett A Department of Otolaryngology, Charles R. Drew University of Medicine and Science, Los Angeles, CA 90059, USA.

Cancer Detect Prev 2000;24(4):314-24
Recently, we presented evidence for the role of MGN-3, an enzymatically modified arabinoxylan extracted from rice bran, in potent activation of human natural killer (NK) cell function in vivo and in vitro. In the current study, we examined the mechanism by which MGN-3 elevated NK cytotoxic activity. We did this by testing the action of MGN-3 on the levels of both tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) secretions and MGN-3 function on the expression of key cell surface receptors. Peripheral blood lymphocytes were treated with MGN-3 at concentrations of 0.1 mg/ml and 1 mg/ml, and supernatants were subjected to enzyme-linked immunosorbent assay. Results showed that MGN-3 is a potent TNF-alpha inducer. The effect was dose-dependent. MGN-3 concentration at 0.1 and 1 mg/ml increased TNF-alpha production by 22.8- and 47. 1-fold, respectively. MGN-3 also increased production of IFN-gamma but at lower levels as compared to TNF-alpha With respect to key cell surface receptors, MGN-3 increases the expression of CD69, an early activation antigen at 16 hours after treatment. Furthermore, the interleukin-2 receptor CD25 and the adhesion molecule ICAM-1 (CD54) were upregulated after treatment with MGN-3. Treating highly purified NK cells with MGN-3 also resulted in increased levels of TNF-alpha and IFN-gamma secretion in conjunction with augmentation of NK cell cytotoxic function. Furthermore, addition of MGN-3 to interleukin-2-activated NK cells resulted in a synergistic induction of TNF-alpha and IFN-gamma secretion. Overall, our data suggest that MGN-3, a novel biological response modifier, can be used as a safe alternative or as an adjuvant to the existing immunotherapeutic modalities.

Akihisa T, Yasukawa K, Yamaura M, Ukiya M, Kimura Y, Shimizu N, Arai K College of Science and Technology, Nihon University, Tokyo, Japan. akihisa@chem.cst.nihon-u.ac.jp

J Agric Food Chem 2000 Jun;48(6):2313-9
Six novel feruloyl esters of triterpene alcohols and sterols, viz., two trans-ferulates, cycloeucalenol and 24-methylenecholesterol trans-ferulates, and four cis-ferulates, cycloartenol, 24-methyelenecycloartanol, 24-methylcholesterol, and sitosterol cis-ferulates, besides five known trans-ferulates, cycloartenol (CAR), 24-methylenecycloartanol (24-MCA), 24-methylcholesterol, sitosterol, and stigmastanol trans-ferulates, and one known cis-ferulate, stigmastanol cis-ferulate, were isolated from the methanol extract of edible rice bran. These and eight other synthetic trans- and cis-ferulates of triterpene alcohols and sterols, along with the corresponding free alcohols, were evaluated with respect to their anti-inflammatory activity against 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation (1 microg per ear) in mice. All of the ferulates showed marked inhibitory activity, and their 50% inhibitory dose (ID(50)) was 0. 1-0.8 mg per ear. On the other hand, whereas two free triterpene alcohols, CAR and 24-MCA, showed strong inhibition (ID(50) 0.2-0.3 mg/ear), eight free sterols examined showed weaker activity (ID(50) 0.7-2.7 mg/ear) than their corresponding ferulates.

Fan H, Morioka T, Ito E First Department of Pathology, University of the Ryukyus, Okinawa, 903-0215, Japan.

Gynecol Oncol 2000 Feb;76(2):170-5
OBJECTIVE: A lipoprotein fraction extracted from rice bran (RBF) has been proved to be nontoxic to normal cells and to possess the ability to derange energy metabolism and induce apoptosis in Ehrlich ascites tumor cells. This study is designed to investigate the therapeutic effects of RBF as an antitumor substance on endometrial adenocarcinoma cells (Sawano). METHODS: Cultured human endometrial adenocarcinoma cells were treated with medium only (untreated), DMSO, or RBF at 100, 200, and 300 microg/ml. Mitotic indexes were counted by Giemsa stain and apoptotic index by fluorescent TUNEL stain for confocal laser scanning microscopy. DNA fragments were examined by agarose gel electrophoresis. RESULTS: Characteristic apoptotic morphology was observed in Giemsa-stained cells and further confirmed by confocal laser scanning microscopy in RBF-treated cells. Growth of Sawano cells was inhibited by RBF in a dose- and time-dependent manner. Apoptotic indexes (AI) showed an increasing tendency, and mitotic indexes (MI) showed a downward tendency. In 300 microg/ml RBF-treated Sawano cells, AI even reached 41.62 2. 23% and MI decreased to 0.79 0.08% at 96 h. Both showed significant differences from to controls and other RBF-treated groups. DNA agarose electrophoresis revealed DNA fragmentation in a ladder pattern. CONCLUSIONS: RBF can induce apoptosis of cultured human endometrial adenocarcinoma cells (Sawano) and inhibit its cell proliferation as an antitumor substance.

Ogawa S Department of Applied Chemistry, Faculty of Science and Technology, Keio University, Yokohama, Japan.

Anticancer Res 1999 Sep-Oct;19(5A):3635-44
This review first concentrates on chemical and biochemical aspects of myo-inositol derivatives, as major components of rice bran, in order to give some help for understanding the roles of the biologically important phosphates. In addition, many biologically active compounds which include inositols and inositol derivatives have also been introduced for a better understanding of cyclitol chemistry.

Wang M, Hettiarachchy NS, Qi M, Burks W, Siebenmorgen T Department of Food Science, University of Arkansas, Fayetteville, 72703, USA.

J Agric Food Chem 1999 Feb;47(2):411-6
Rice bran protein isolate (RBPI) containing approximately 92.0% protein was prepared from unstabilized and defatted rice bran using phytase and xylanase. The yield of RBPI increased from 34% to 74.6% through the use of the enzymatic treatment. Nitrogen solubilities of RBPI were 53, 8, 62, 78, 82, and 80% at pHs 2.0, 4.0, 6.0, 8.0, 10.0, and 12.0, respectively. Differential scanning calorimetry showed that RBPI had denaturation temperature of 83.4 degrees C with low endotherm (0.96 J/g of protein). RBPI had similar foaming properties in comparison to egg white. But emulsifying properties of RBPI were significantly lower than those of bovine serum albumin. The result of amino acid analysis showed that RBPI had a similar profile of essential amino acid requirements for 2-5-year-old children in comparison to that of casein and soy protein isolate.

Ghoneum M Department of Otolaryngology, Drew University of Medicine and Science, Los Angeles, California 90056, USA.

Biochem Biophys Res Commun 1998 Feb 4;243(1):25-9
MGN-3 an arabinoxylane from rice bran that has been enzymatically modified with extract from Hyphomycetes mycelia, was tested for anti-HIV activity in vitro. MGN-3 activity against HIV-1 (SF strain) was examined in primary cultures of peripheral blood mononuclear cells. MGN-3 inhibited HIV-1 replication by: (1) inhibition of HIV-1 p24 antigen production in a dose dependent manner--MGN-3 concentrations of 12.5, 25, 50, and 100 micrograms/ml showed 18.3, 42.8, 59, and 75% reduction in p24 antigen, respectively; and (2) inhibition of syncytia formation maximized (75%) at concentrations of 100 micrograms/ml. Further studies showed that ingestion of MGN-3 at concentration of 15 mg/kg/day resulted in a significant increase in T and B cell mitogen response at 2 months after treatment: 146% for PHA, 140% for Con A, and 136.6% for PWM mitogen. We conclude that MGN-3 possesses potent anti-HIV activity and in the absence of any notable side effects, MGN-3 shows promise as an agent for treating patients with AIDS.

Akiyama T, Shibuya N, Hrmova M, Fincher GB National Hokkaido Agricultural Experimentation Station, Sapporo, Japan.

Carbohydr Res 1997 Feb 14;297(4):365-74
A (1-->3)-beta-glucanase with an apparent M(r) of 29,000 and an isoelectric point of 4.0 has been purified 2000-fold from extracts of rice bran, using fractional precipitation with ammonium sulfate, anion exchange chromatography, size-exclusion chromatography, chromatofocussing, and hydrophobic interaction chromatography. The enzyme can be classified with the EC 3.2.1.39 group, because it releases laminarabiose and higher laminara-oligosaccharides from linear (1-->3)-beta-D-glucans with an action pattern that is typical of (1-->3)-beta-D-glucan endohydrolases. However, the introduction of substituents or branching in the (1-->3)-beta-D-glucan substrates causes a marked decrease in the rate of hydrolysis. Thus, substituted or branched (1-->3)-beta-D-glucans of the kind commonly found in fungal cell walls are less susceptible to hydrolysis than essentially linear (1-->3)-beta-D-glucans. Kinetic analyses indicate an apparent Km of 42 microM, a kcat constant of 67 s-1, and a pH optimum of 5.0 during hydrolysis of the (1-->3)-beta-D-glucan, laminaran, from Laminaria digitata. The first 60 NH2-terminal amino acid residues of the purified rice (1-->3)-beta-glucanase contain blocks of amino acids that are conserved in other cereal (1-->3)-beta-glucanases. Although the precise tissue location and function of the enzyme in rice bran are not known, it is likely that it is concentrated in the aleurone layer and that it plays a preemptive role in the protection of ungerminated grain against pathogen attack.

Tashiro M, Ikegami S Department of Food Science and Nutrition, Kyoto Prefectural University, Japan.

J Nutr Sci Vitaminol (Tokyo) 1996 Aug;42(4):367-76
Rice bran trypsin inhibitor (RBTI) was digested by pepsin alone or by pepsin and pancreatin with or without bovine serum albumin (BSA) to clarify the changes in trypsin inhibitory activity, apparent antigenicity, and molecular size of RBTI. In vitro pepsin digestion of RBTI in the absence of BSA caused the gradual loss of the trypsin inhibitory activity and antigenicity. This was mostly due to a progressive degradation of the native 14.5-kDa RBTI molecule to small molecular mass products. The presence of BSA in the digestion mixture prevented the RBTI degradation and was accompanied with a considerable protection of the activity and antigenicity. Similar results were also given by in vitro pepsin-pancreatin digestion. These findings suggest that RBTI may be present in its active form in the gastrointestinal tract when fed to animals, especially with a dietary protein.

Fukushima M, Nakano M Department of Bioresource Chemistry, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido, Japan.

Br J Nutr 1995 May;73(5):701-10
The effect of a probiotic composed of Bacillus, Lactobacillus, Streptococcus, Saccharomyces and Candida species (each at 10(7-8) colony-forming units (cfu)/g rice bran), given at a level of 150 g/kg diet for 6 weeks, on lipid metabolism was examined in the faeces, serum and liver of male rats. Liver weight decreased 35% in the rats fed on a high-fat, high-cholesterol diet containing the probiotic. Total cholesterol concentration in the serum was significantly lower in the probiotic group than in the control group throughout the experimental period in rats fed on the high-fat, high-cholesterol diet, and HDL-cholesterol concentration was significantly higher (P < 0.05) in the probiotic group than in the control group which was fed for the 6 week experimental period on a basal diet. The serum VLDL'? cholesterol concentration in the probiotic groups were reduced compared with those of the corresponding control groups. The probiotic groups fed on the high-fat, high-cholesterol diet and the basal diet had lower hepatic cholesterol concentrations than did the corresponding control groups (P < 0.05). Hydroxymethylglutaryl coenzyme A reductase (NADPH) (EC 1.1.1.34) activity in the liver was lower in rats fed on the high-fat, high cholesterol diet with the probiotic. The neutral and acidic steroid concentrations in faeces were higher in the probiotic group than in the control group fed on the high-fat, high-cholesterol diet. Escherichia coli decreased and Bifidobacterium and Eubacterium increased in the faecal microflora of rats fed on the dietary probiotic. Lactobacillus in the probiotic groups was higher than that in the control groups. The present study shows that the probiotic promotes Bifidobacterium and Eubacterium in the faecal microflora, and reduces cholesterol levels in the serum and liver of rats.

Hiraga Y, Nakata N, Jin H, Ito S, Sato R, Yoshida A, Mori T, Ozeki M, Ikeda Y Zeria Pharmaceutical Co., Ltd., Central Research Laboratories, Saitama, Japan.

Arzneimittelforschung 1993 Jul;43(7):715-21
In order to investigate the effect of cycloartenol ferulic acid ester (CFE, CAS 21238-33-5), a component of gamma-oryzanol which is a phytosterol derived from rice bran, on the central nervous system, a variety of pharmacological tests were performed. It was shown that CFE had a suppressant effect on the central nervous system, but its properties were different from those of existing major and minor tranquilizers. In addition, its efficacy in several models of cerebral dysfunction was demonstrated. Since any clear effects could not be obtained under the treatments with gamma-oryzanol, CFE seems to be more useful than gamma-oryzanol. Thus the results of this study suggest that CFE may serve as a new plant-derived cerebral activator possessing a wide range of pharmacological actions.

Tsuji H, Ikeda K, Nomiyama K, Fujishima M Second Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka.

Fukuoka Igaku Zasshi 1993 May;84(5):282-6
To investigate the therapeutic effects of rice bran fiber (30 g/day) and cholestyramine (12 g/day) for Yusho, clinical signs and symptoms, and laboratory examinations were studied before, during and after 14 day-treatment in four patients with Yusho. The increases of bowel movements and abdominal distention were observed in two of these patients, although no effect was seen in physical findings. In peripheral blood cells, red blood cell counts decreased significantly, from 430 47 x 10(4)/mm3 (mean SD) to 378 48 x 10(4)/mm3 (p < 0.01) after therapy. Hemoglobin as well as hematocrit levels were also reduced significantly afer the therapy. However, no significant effect of the treatment was observed in white blood cell counts or platelet counts. In biochemical parameters, a significant depression was observed in total cholesterol levels after the therapy (from 262 31 mg/dl to 179 33 mg/dl; p < 0.005). A significant elevations was observed in serum levels of alanine aminotransferase and sodium, while significant depressions were found in serum levels of cholinesterase, total protein, albumin, gamma-globulin, and potassium.

Aoe S, Oda T, Tojima T, Tanaka M, Tatsumi K, Mizutani T Technical Research Institute, Snow Brand Milk Products, Saitama, Japan.

Nutr Cancer 1993;20(1):41-9
The effect of rice bran hemicellulose (RBH) on 1,2-dimethylhydrazine- (DMH) induced intestinal carcinogenesis was studied in male Fischer 344 rats. Rats were fed a basal control diet or a diet containing 2% or 4% RBH at five weeks of age. At 6 weeks of age, all animals were given an intraperitoneal injection of DMH (20 mg/kg body wt) at weekly intervals for 20 weeks and autopsied 7 weeks after the last injection. The incidence of DMH-induced colon tumors was significantly lower in rats fed the 4% RBH diet than in rats fed the basal control diet (p < 0.05). The number of colon tumors per rat was also significantly lower in rats fed the 4% RBH diet than in rats fed the basal control diet (p < 0.05). The present study suggested that the water-soluble RBH played a preventive role in DMH-induced large bowel carcinogenesis in Fischer 344 rats.

Qureshi AA, Peterson DM, Hasler-Rapacz JO, Rapacz J Advanced Medical Research, Madison, Wisconsin 53719. U.S. Department of Agriculture, Agricultural Research Service, Cereal Crops Research Unit, Madison, Wisconsin 53705. Department of Agronomy, University of Wisconsin, Madison, Wisconsin 53706 and. Departments of Genetics and Animal Sciences, University of Wisconsin, Madison, Wisconsin.

J Nutr 2001 Feb;131(2):223-230
A tocotrienol-rich fraction (TRF(25)) and novel tocotrienols (d-P(21)-T3 and d-P(25)-T3) of rice bran significantly lowered serum and low density lipoprotein cholesterol levels in chickens. The present study evaluated the effects of novel tocotrienols on lipid metabolism in swine expressing hereditary hypercholesterolemia. Fifteen 4-mo-old genetically hypercholesterolemic swine were divided into five groups (n = 3). Four groups were fed a corn-soybean control diet, supplemented with 50 ?g of either TRF(25), gamma-tocotrienol, d-P(21)-T3 or d-P(25)-T3 per g for 6 wk. Group 5 was fed the control diet for 6 wk and served as a control. After 6 wk, serum total cholesterol was reduced 32-38%, low density lipoprotein cholesterol was reduced 35-43%, apolipoprotein B was reduced 20-28%, platelet factor 4 was reduced 12-24%, thromboxane B(2) was reduced 11-18%, glucose was reduced 22-25% (P: < 0.01), triglycerides were reduced 15-19% and glucagon was reduced 11-17% (P: < 0.05) in the treatment groups relative to the control. Insulin was 100% greater (P: < 0.01) in the treatment groups than in the control group. Preliminary data (n = 1) indicated that hepatic activity of the 3-hydroxy-3-methylglutaryl-coenzyme A reductase was lower in the treatment groups, and cholesterol 7alpha-hydroxylase activity was unaffected. Cholesterol and fatty acid levels in various tissues were lower in the treatment groups than in control. After being fed the tocotrienol-supplemented diets, two swine in each group were transferred to the control diet for 10 wk. The lower concentrations of serum lipids in these four treatment groups persisted for 10 wk. This persistent effect may have resulted from the high tocotrienol levels in blood of the treatment groups, suggesting that the conversion of tocotrienols to tocopherols may not be as rapid as was reported in chickens and humans.

Hudson EA, Dinh PA, Kokubun T, Simmonds MS, Gescher A Medical Research Council Toxicology Unit, University of Leicester, United Kingdom. eah5@le.ac.uk

Cancer Epidemiol Biomarkers Prev 2000 Nov;9(11):1163-70
Rice is a staple diet in Asia, where the incidence of breast and colon cancer is markedly below that in the Western world. We investigated potential colon and breast tumor-suppressive properties of rice, testing the hypothesis that rice contains phenols that interfere with the proliferation or colony-forming ability of breast or colon cells. Brown rice, its white milled counterpart, and bran from brown rice were boiled and extracted with ethyl acetate. The extracts were analyzed by high pressure liquid chromatography-mass spectrometry. Eight phenols, protocatechuic acid, p-coumaric acid, caffeic acid, ferulic acid, sinapic acid, vanillic acid, methoxycinnamic acid, and tricin, were identified in the extracts of bran and intact brown rice. These extracts were separated into nine fractions by column chromatography. The effect of bran extract and its fractions at 100 microg/ml on cell viability and colony-forming ability of human-derived breast and colon cell lines was assessed. Bran extract decreased numbers of viable MDA MB 468 and HBL 100 breast cells and colon-derived SW 480 and human colonic epithelial cells as judged by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4 -sulfophenyl)-2H-tetrazolium assay. It also reduced colony formation of SW 480 colon and MDA MB 468 breast cells. Of the eight phenols identified in the brown rice bran, when applied at 50 microM, caffeic acid decreased numbers of all cell types except HBL 100. Tricin, ferulic acid, and methoxycinnamic acid interfered with cell viability in one or more cell lines. Tricin (50 microM) and the other phenols (200 microM) inhibited colony formation of SW 480 cells. Clonogenicity of MDA MB 468 cells was inhibited by caffeic acid, ferulic acid, and tricin (50 microM). Tricin was the most potent anticlonogenic of the compounds with IC50s of 16 microM in the SW 480 colon cells and 0.6 microM in the MDA MB 468 breast cells. The results suggest that: (a) brown rice and bran contain compounds with putative cancer chemopreventive properties; (b) certain phenols contained in brown rice bran, e.g., tricin, may be associated with this activity; and (c) these phenols are present at much lower levels in white than in brown rice. Thus, the consumption of rice bran or brown rice instead of milled white rice may be advantageous with respect to cancer prevention.

Akihisa T, Yasukawa K, Yamaura M, Ukiya M, Kimura Y, Shimizu N, Arai K College of Science and Technology, Nihon University, Tokyo, Japan. akihisa@chem.cst.nihon-u.ac.jp

J Agric Food Chem 2000 Jun;48(6):2313-9
Six novel feruloyl esters of triterpene alcohols and sterols, viz., two trans-ferulates, cycloeucalenol and 24-methylenecholesterol trans-ferulates, and four cis-ferulates, cycloartenol, 24-methyelenecycloartanol, 24-methylcholesterol, and sitosterol cis-ferulates, besides five known trans-ferulates, cycloartenol (CAR), 24-methylenecycloartanol (24-MCA), 24-methylcholesterol, sitosterol, and stigmastanol trans-ferulates, and one known cis-ferulate, stigmastanol cis-ferulate, were isolated from the methanol extract of edible rice bran. These and eight other synthetic trans- and cis-ferulates of triterpene alcohols and sterols, along with the corresponding free alcohols, were evaluated with respect to their anti-inflammatory activity against 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation (1 microg per ear) in mice. All of the ferulates showed marked inhibitory activity, and their 50% inhibitory dose (ID(50)) was 0. 1-0.8 mg per ear. On the other hand, whereas two free triterpene alcohols, CAR and 24-MCA, showed strong inhibition (ID(50) 0.2-0.3 mg/ear), eight free sterols examined showed weaker activity (ID(50) 0.7-2.7 mg/ear) than their corresponding ferulates.

Koba K, Liu JW, Bobik E, Sugano M, Huang YS Siebold University of Nagasaki, Nagayo, Japan.

J Nutr Sci Vitaminol (Tokyo) 2000 Apr;46(2):58-64
Rice bran oil (RBO), when blended with safflower oil (SFO) at the ratio of 7 to 3, has been shown to lower serum cholesterol in humans consuming cholesterol. The mechanism as to how this oil blend exerts its effect is not yet clear. This study examined the effect of cholesterol supplementation on the cholesterol-lowering ability of different RBO/SFO blends. Male Sprague Dawley rats (4 wk old) were fed purified diets containing 10% fat with or without the addition of 0.5% cholesterol for 3 wk. The fat was either SFO or RBO alone, or the mixture of these two oils at the ratio of 7: 3 (7S/3R), 5:5 (5S/5R), or 3:7 (3S/7R). Without cholesterol supplementation, there were no significant differences in the serum and liver total cholesterol levels among different dietary fats. However, the HDL cholesterol level of rats fed the RBO-containing diets (especially in rats fed the 3S/7R diet) was higher than that of rats fed the diet containing SFO alone. This resulted in an increase in the ratio of HDL/total cholesterol-a desirable outcome. Supplementation of the diets with 0.5% cholesterol significantly increased the cholesterol level in both the serum and the liver. Increasing the proportion of RBO in the diet further raised the total cholesterol level in the serum whereas it reduced liver cholesterol. Then, the specific effect of the 3S/7R mixture on the ratio of HDL/total cholesterol disappeared. These findings suggest that cholesterol supplemented at the level of 0.5% in this study masked the cholesterol-lowering effect of RBO. Smaller percentages of polyunsaturated fatty acid (i.e., 18:2n-6) in the RBO-containing diets than in the SFO diet might have reduced their ability to dispose the circulating serum cholesterol into the liver.

Sugano M, Tsuji E Laboratory of Food Science, Kyushu University School of Agriculture, Fuluoka, Japan.

J Nutr 1997 Mar;127(3):521S-524S
A range of human and animal studies have shown that rice bran oil (RBO) is an edible oil of preference for improving serum cholesterol levels and lipoprotein profiles with similarity to the more commonly used vegetable oils such as corn oil and safflower oil. Of particular interest is the observation that blending RBO with safflower oil at a definite proportion (7:3, wt/wt) magnifies the hypocholesterolemic efficacy, compared with the effect of each oil alone. Although the mechanism underlying this effect is not apparent at present, the blending may have a practical significance. The blending effect was reproduced in rats fed a cholesterol-enriched diet, and there was also a decrease in liver cholesterol. The occurrence of peculiar components such as gamma-oryzanol and tocotrienols could be responsible for the hypocholesterolemic effect of RBO.

Sugano M, Tsuji E Laboratory of Food Science, Kyushu University School of Agriculture, Fukuoka, Japan.

Biomed Environ Sci 1996 Sep;9(2-3):242-6
The available data in humans suggest that rice bran oil (RBO) is an edible oil of preference for improving plasma lipid and lipoprotein profiles similar to more commonly used vegetable oils. The observation that blending RBO with safflower oil at a specific proportion magnifies the hypocholesterolemic efficacy is of particular interest with regard to utilization of this oil. The occurrence of peculiar components such as gamma-oryzanol and tocotrienols in RBO might be responsible for its hypocholesterolemic effect.

Prakash J Department of Studies in Food Science and Nutrition, University of Mysore, Manasagangotri, India.

Crit Rev Food Sci Nutr 1996 Jul;36(6):537-52
Rice bran, a good source of protein and fat, is at present underutilized as a food material. The potential of producing rice bran at the global level is 27.3 million t. The presence of enzyme lipase in rice bran causes rapid deterioration of oil to free fatty acids and glycerol. Various stabilization techniques involving heat treatment, low-temperature storage, chemical treatment, control of relative humidity during storage, and simultaneous milling and extraction were evolved to inactivate lipase. Multiple forms of rice bran lipase have been identified. Fractional classification of proteins reveals a high percentage of albumins and globulins. Proteins can be extracted from full-fat or defatted rice bran by alkaline extraction and acid or heat precipitation. Extraction procedures influence the protein content of concentrates, which ranged from 19.4 to 76.1% in concentrates from full-fat rice bran and 17.5 to 85.0% in concentrates from defatted rice bran. The PER of rice bran ranges from 1.59 to 2.04 and that of protein concentrates from 1.99 to 2.19. Available lysine contents of protein concentrates ranged from 54 to 58.8%. The essential amino acid profiles of protein concentrates indicate that threonine and isoleucine are limiting amino acids. Various functional properties of rice bran protein concentrates have also been investigated that are known to be influenced by drying technique and stabilization treatment of rice bran. Rice bran has been used in food as full-fat rice bran, defatted rice bran, and in the form of rice bran oil and protein concentrates. Full-fat and defatted rice bran have been used in bakery products, breakfast cereals, wafers, as a protein supplement, binder ingredients for meats and sausages, and as a beverage base. Incorporation of protein concentrates have been studied in bread, beverages, confections, and weaning foods.