Preparation And Purification Of Soybeam Peptides With Anti-oxidant Activity

Soybean peptides, the combination of three to fifty amino acids,are the extraneous active substance after controlled hydrolysis and refining of soybean protein. The research is to find a efficient and cheap way of preparing the anti-oxidant peptides in short time basic on the connection of the molecular structure and the molecular weight of peptides with anti-oxidation. Select the way of purification to get the effect of anti-oxidant peptides improved .Basic on the research, production and development of product of anti-oxidant peptides may go easier.The molecular structure of the anti-oxidant peptides is effected by enzyme but the molecular weight effected by the degree of hydrolysis. Indicate the anti-oxidation of five kinds of hydrolysate hydrolyzed with pepsin, papain, bromelain, neutral protease and alkaline protease respectively in each optimum environment of hydrolysis with soybean protein as substrate. Result shows that hydrolysates hydrolyzed with bromelain, neutral protease and alkaline protease have the strongest reducing capacity and the ability of scavenging superoxide anion radical and hydrogen peroxide. Select hydrolysis conditions for preparing soybean peptides with anti-oxidant activity. Results show that the peptides, which show highest anti-oxidant activity, have been prepared by1000U/g bromelain, 2000U/g neutral protease and 2000U/g alkaline protease together for 4hours under the hydrolysis conditions of pH6.0,temperature at 50℃and substrate concentration at 8.0%.Reducing ability reaches 0.898, ability of scavenging superoxide free radical 40.93% and ability of scavenging hydrogen peroxide 33.37% separately. Decide the hydrolysis time according to the anti-oxidation After selecting temperature, pH and substrate concentration in order to make the enzyme to take a biggest affectionAfter ultra-filtration the peptides (5KDa-10KDa) show stronger reducing ability and the fact that the molecular weight is concentrated is also indentified by tricine -SDS-PAGE electrophoresis. Peptides (<5KDa)show stronger ability of scavenging superoxide free radical and hydrogen peroxide and the molecular weight is not concentrated and there may be many kinds of peptides. The peptides(<5KDa) are separated by high-speed counter-current chromatography(HSCCC),and then purified with RP-HLPC, ability of scavenging superoxide free radical and hydrogen peroxide of the purified peptides separately reaches 50.2%±0.89 and 49.14%±0.11 and increases by 43.72% and 71.64% respectively contrast to the hydrolysate. But the reducing ability of purified peptides is still weaker than the peptides between 5KDa and 10KDa.Take the compound enzyme system of pepsin- compound trypsinase to simulate the digestive system. The result shows that the ability of scavenging superoxide free radical and hydrogen peroxide of purified peptides after hydrolysis becomes little weaker and the anti-oxidation in the body can not be effected.