67B-1 |
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I. PARAMAN1, N. S. Hettiarachchy2, S. A. Heo2, and K. H. Tran1. (1) Department of Food Science, University of Arkansas, 2650 N. Young Ave., Fayetteville, AR 72704, (2) Dept. of Food Science, Univ. of Arkansas, 2650 N. Young Ave., N-218 Food Science Bldg., Fayetteville, AR 72704-5690 Rice bran is acquiring more interest in the food industry because of its unique nutritional value and nutraceutical properties in a co-product after oil extraction. It contains approximately 18-22% high quality, hypoallergenic protein. Peptides produced from proteins have been shown to have several bio-activities and have numerous applications as dietary supplements and pharmaceutical preparations. Literature information is lacking in producing rice bran peptides and demonstrating their health benefits in preventing major chronic diseases. The objective of this study is to produce peptides form rice bran, separate by ultrafiltration, and evaluate peptides for antimutagenic activity. A 3% (W/V) suspension of heat-stabilized defatted rice bran (150 ml) was hydrolyzed with 1% papain at 37°C, pH 8.0 with shaking at 200 rpm for 6 hours, and then the enzyme was inactivated by heat. Hydrolysates were fractionated by ultrafiltration, and fractions with various molecular sizes, F1 (>30 kDa), F2 (10-30 kDa), F3 (5-10 kDa), F4 (3-5 kDa), and F5 (3 kDa<), were freeze-dried and evaluated with an amount of 500 mg for antimutagenic activity by Ames test using Salmonella typhimurium TA 98 (his- mutant/frameshift mutant) against phenazine methosulfate (mutagen, 25 ml, 20 mg/ml). The percentage inhibition of mutagenesis was calculated using the following equation: inhibition %=[1-(number of revertants in the presence of fraction/number of revertants in the absence of fraction)]*100. Among the five fractions, the F3 (5-10 kDa) fraction showed the highest antimutagenic activity of 55.2%. The antimutagenic activities of the F1, F2, F4, and F5 fractions were 7.1, 13.3, 22.2, and 24.0%, respectively. Hydrolysates having high molecular size (> 30 kDa) have less antimutagenic activity. The outcome of this study will result in producing rice bran protein peptides that have antimutagenic activity. These peptides can find application as bio-peptides in nutraceutical and pharmaceutical products.
Session 67B, Food Chemistry: Antioxidants and bioactive agents
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