67B-7 |
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M. CHA, Dept. of Hotel Restaurant Institution Management & Dietetics, Kansas State Univ., 245 Justin Hall, Manhattan, KS 66502 and J. R. Park, Dept. of Food & Nutrition, Yeungnam Univ., Daedong, Gyeongsan, South Korea. Research has shown that Korean traditional soy fermented foods have many health promoting effects, such as ACE(Angiotensin Converting Enzyme) inhibitory activity, derived from peptides and hydrolysates. ACE inhibitory peptides inhibit the angiotensin converting enzyme and then contribute to reducing blood pressure. Daily consumption of food that has some peptides with potent ACE inhibitory activity could be effective in maintaining healthy blood pressure, and thus have potential for commercialization, because of their health benefits. The preparation and properties of the soy-protein-derived ACE inhibitory hydrolysates by Bacillus subtilis SS103 screened through Korean traditional soy sauce are investigated in this study. Angiotensin I-converting enzyme (ACE) inhibitory hydrolysates were prepared from soy protein digested by Bacillus subtilis SS103 after ultrafiltration and cation exchange fractionation. ACE inhibition was assayed by a modification of the method of Cheung and Cushman. Stability of hydrolysates was measured at various temperatures and pH values, and also examined by treatment with pepsin and pancreatin. The degree of hydrolysis was assessed at different reaction time. Inhibitory kinetics of hydrolysates were verified at various substrate(HHL) concentrations incubating with ACE solution in soy-derived ACE inhibitory hydrolysates. The final yield was 7.6% (protein basis), purification fold was 18.6 and IC50 value was 0.045 mg of protein/ml. High ACE inhibitory activity was shown at the optimal condition of enzyme concentration and reaction time, 1 wt% and 2hrs, respectively. ACE inhibitory activity was maintained after incubation at various temperatures and pH values, and treatment by gastric enzymes in vitro. These hydrolysates were shown to be a competitive inhibitors as evaluated by the Lineweaver-Bulk Plot. Result indicated that the protease in this study could serve for producing the ACE inhibitory hydrolysates. These ACE inhibitory hydrolysates from soybean protein could be also serve as a strong biofunctional food having much more economic advantages than purified one peptide to lower the blood pressure in the food market.
Session 67B, Food Chemistry: Antioxidants and bioactive agents
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