Study On Enzymatic Production Of Soybean Antioxidant Peptides

In this study,11S and 7S soybean globulin were prepared from soybean meal by Nagano method.The purity of 11S and 7S soybean globulin was 86.6%and 73.6%respectively.Through single factor test,trypsinase was selected from five enzymes,including alkaline protease,trypsin,flavor protease,papain and soybean protein modifying enzyme,which had better hydrolysis effect on 11S and 7S soybean globulin.The optimum hydrolysis conditions of 11S and 7S soybean globulin hydrolyzed by trypsin were determined by single factor test and response surface analysis:The optimum conditions for hydrolysis of soybean 11S globulin by trypsin were the ratio of enzyme to substrate 4900 U/g,pH 8.1,temperature 44℃and hydrolysis time 2.6 h,under which the degree of hydrolysis was 89.25%;The optimum conditions for Trypsin Hydrolysis of soybean 7S globulin were the ratio of enzyme to substrate 5900 U/g,pH7.9,temperature 52℃and hydrolysis time 3 h.Under these conditions,the degree of hydrolysis was 94.16%.The antioxidant activities of 11S and 7S soybean globulin trypsin hydrolysates were investigated by pyrogallol method and Rhodamine B-Feton system spectrophotometry.The results showed that soybean 11S globulin hydrolytic peptide,soybean 7S globulin hydrolytic peptide and soybean protein isolate hydrolytic peptide all had good scavenging effect on O₂^-and·OH.The scavenging rate increased with the increase of soybean peptide content.The order of scavenging ability was:7S globulin hydrolytic peptide>11S globulin hydrolytic peptide>soybean protein isolate hydrolytic peptide.When the concentration of peptide solution was 12 mg/mL,the clearance rate of 7S globulin hydrolyzed peptide was the highest,reaching 60.84%;when the concentration of peptide solution was 10 mg/mL,the clearance rate of 11S globulin hydrolyzed peptide was the highest,reaching 46.86%.When the concentration of peptide solution was 0.5 mg/mL,the clearance rate of 7S globulin hydrolyzed peptide was the highest,reaching 42.35%.When the concentration of peptide solution was 0.5mg/mL,the clearance rate of 11S globulin hydrolyzed peptide was the highest,reaching33.73%.A soybean peptide sports drink with quick recovery of physical strength and protein supplement was developed with soybean peptide as the main raw material,sucrose as sweetener,malic acid as an acidifying agent,adding vitamin C,edible salt,lemon flavor and other ingredients.On the basis of single factor test and sensory score as the evaluation index,three factors and three levels of response surface analysis test were designed to determine the optimal formula of soybean peptide sports drink by selecting the factors of soybean peptide,sucrose and malic acid addition:When soybean peptide,sucrose and malic acid were added 3.3%,3.4%and 1.8%,respectively the sensory score of the beverage was 90.33.