67B-6 |
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K. H. TRAN1, N. S. Hettiarachchy2, and S. A. Heo2. (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 Soy protein has been extensively studied and its nutritional, nutraceutical and health benefits have been documented. Though rice protein is of high quality and is hypoallergenic, little is known about its peptides in comparison to soy protein. Bio-peptides have been documented to have physiological activities. The objective of this study is to prepare soy and rice protein hydrolysates using bromelain and to separate and evaluate peptide fractions for antimutagenic activity. Two percent of soy and rice protein solutions were enzymatically hydrolyzed by bromelain at 37°C at pH 6.0 with shaking at 200 rpm for three hours. Soy and rice protein hydrolysates were fractionated by ultrafiltration. The molecular size of fractions were: F1 (> 30 kDa), F2 (10-30 kDa), F3 (5-10 kDa), F4 (3-5 kDa), and F5 (3kDa <). These fractions were freeze-dried and evaluated for antimutagenic activities with varying concentrations of fractions (10-500 µg) by Ames assay. Salmonella typhimurium strains TA98 and TA100 were used for antimutagenic test. Phenazine methosulfate, consisting of 10 µg per test plate, was used as the mutagen. The percentage of antimutagenic activity was measured by comparing the colony forming units of test plates with/without soy or rice proteins fractionated hydrolysates in the presence of Phenazine methosulfate. Fraction 3 of soy protein and rice protein hydrolysates exhibited the highest inhibition percentage of antimutagenic activity. The antimutagenic activities of F3 fraction from soy and rice protein hydrolysate were 93.5% and 73.5% against the strain of TA98, respectively. The peptides in Fraction 3 hold promises for nutraceutical and pharmaceutical applications.
Session 67B, Food Chemistry: Antioxidants and bioactive agents
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