Antioxidative Activities Of Corn Protein And Corn Protein Hydrolysate In Vitro Digests

In this study, Alkali extraction and acid precipitation were employed to produce corn total protein from the corn gluten meal which was pretreated by decolorization and starch removal, then the corn protein hydrolysate with high degree of hydrolysis (DH) was produced with the filtrated protease by response surface methodology; The varise of the antioxidative activities of corn protein and corn protein hydrolysate with high DH in vitro digestion was studied, and the antioxidative activities of both digestive production’s component that separated by Sephadex G-15 also be studied. The results were as follows:Through the analysis of DH, content of amino nitrogen and content of soluble protein of corn protein under Alcalase, neutral protease and papaya protease, the finall choise was Alcalase.The final Optimal hydrolysis conditions were proteases dosage (E/S)3.5%, hydrolysis temperature 49.7℃, substrate concentration 23 g/L, hydrolysis time 4 h, pH 9.0, with the conditions were determined by single factor experiments and response surface experiments.The varise of the antioxidative activities of corn protein (CP) and corn protein hydrolysate with high DH (CPHHDH) in vitro digestion was studied, the final digestive productions’DPPH scavenging rate were 11.33% and 9.72%, O2-· scavenging rate were 11.33% and 9.72%, OH scavenging rate were 44.36% and 46.92%, reduction ability were 0.378å'Œ0.388. In the whole process of digestion, CP always had a higher DPPH scavenging ability than CPHHDH and CPHHDH always had a higher-OH scavenging ability than CP. Comparison of both O2-· scavenging ability, CPHHDH was higher than CP in the gastric digestion stage, while CP was higher than CPHHDH in the intestinal digestion stage. Comparison of both reduction ability, CP was higher than CPHHDH in the gastric digestion stage, while CPHHDH was higher than CP in the intestinal digestion stage.SephadexG-15 gel chromatography was used to separate the final digestive productions of CP and CPHHDH into fractions, respectively got 3 fractions and 4 fractions. The DPPH-scavenging rate and reduction ability of each fraction were determined, test results showed that both their fraction I had the the strongest antioxidant activities, and the antioxidant activities of other fraction decreased in turn respectively. The DPPH scavenging rate of both their fraction I were far higher than the final digestive production without separating; Reduction ability of both their fraction I were lower than the final digestive production without separating.