Study On The Key Technology Of Preparing Germinated Soybean Peptide

Germinated soybean peptide is a kind of bioactive peptide prepared by enzymatic hydrolysis of soybean after germinating.The bioactive peptide is a kind of protein fragment with a variety of bioactive functions,which can be easily absorbed and utilized by the human body.Therefore,they currently become a research hotspot in the fields of food,biology and medicine.In this study,germinated soybean was used as the research object to prepare bioactive peptides and to carry out basic research.The main research contents and results are as follows:Firstly,soybean was germinated at different time lengths,and the changes in moisture content,protein content,amino acid content,isoflavones content and total antioxidant capacity of soybean in different germination states were determined.The results showed that the soybean seeds swelled rapidly in water at the initial soaking stage,and the water content increased gradually to about70%with the extension of germination time.The protein content of soybean increased first and then decreased during germination,and reached the highest value of 40.20±0.86%at 48 h of germination.The content of glutamic acid was the highest and the content of methionine was the lowest in all the germination states.The content of total amino acids increased with the prolonging of germination time.During soybean germination,genistein and daidzein contents were significantly increased,while the other groups showed a trend of increasing at first and then decreasing.36 h before soybean germination,genistein content was the highest,accounting for 40%-60%of the total isoflavonoids content.At 12 h of germination,the total antioxidant capacity of soybean was 5.44±0.08 mmol/gprot.Secondly,germinated soybean peptides were prepared by compound protease,and the process conditions were optimized by response surface test.When the enzymatic hydrolysis time was 4.98 h,the amount of enzyme was2.95%,and the ratio of solid to liquid was 1:11.87,the hydrolysis degree of germinated soybean peptides was 56.49±0.25%at most,and the total antioxidant capacity of germinated soybean peptides was 1.20±0.01 m M.Finally,with ultrafiltration and glucan gel Sephadex G-15 to separate and purify germination soybean peptides,measure the molecular weight and antioxidant activity in vitro of the isolation components.The results showed that the germination soybean peptides in less than 3 k Da peptide accounted for97.73%,has reached the level of commercial soybean peptide,ultrafiltration after germination of soybean peptides antioxidant activity is better than that of commercial soybean peptide and germinated soybean peptide.The total antioxidant capacity,the activity of scavenging ABTS^·+ion and DPPH free radical of GSP3 were significantly better than those of other components.