Research On Preparation Of Antioxidant Peptides By Sesame 11s Protein

A large amounts of sesame cake are produced during sesame oil processing.It contains rich sesame protein.In order to avoid the waste of protein resources,and increase its utilization value,The development and utilization of sesame protein is becoming more and more important.At present,the sesame whole protein research has many reports,there are few studies on the specific components.Sesame 11 S protein is the main body of sesame protein,accounting for about 60 %.Therefore,The study of sesame 11 S protein has a positive effect on the further exploration of sesame protein.In this paper,the preparation,structure and function properties,hydrolysis preparation and purification of antioxidant peptides of sesame 11 S protein were studied.Taken defatted sesame cake deriving from subcritical extraction as the raw material,the performance of preparation of sesame 11 S globulin by salting out,combination of alkali extraction and salting out,combination of alkali extraction,ultrafiltration and salting out was investigated,the structure and property of sesame 11 S globulin were also analyzed.Results showed that the method composed of alkali extraction,ultrafiltration and salting-out was suitable to prepare sesame 11 S globulin due to high protein yield and purity(the yield rate of 75.47 % and the purity of 83.18 %),and nearly same with the ratio of acid subunits to alkali subunits of sesame 11 S globulin in raw material.Sesame 11 S globulin showed some difference with sesame protein in the amino acid composition,especially high side-chain amino acid content found.There were basic similar in secondary structure between sesame protein and sesame 11 S globulin,however contents of β-sheet,β-turn,β-antiparallel in sesame 11 S globulin were slightly high.Sesame 11 S globulin exhibit the high surface hydrophobicity.The water holding capacity,emulsifying capacity,foam stability of sesame 11 S globulin were weaker than these of sesame protein.the performance of antioxidant peptide generated from sesame 11 S protein hydrolyzed by single or complex protease in six common proteases was evaluated by yield of peptide,degree of hydrolysis,antioxidant capability.Results showed that compared with papain,neutral protease and bromelain,Alcalase,Alkaline protease 2709,Trypsin could producehigher antioxidant hydrolysate.The collaborative hydrolysis of bienzyme enabled to increase the degree of hydrolysis and antioxidant capacity,the optimal hydrolysis conditions was the enzyme activity rate of Alcalase to trypsin was 1:1.The optimum conditions for the preparation of antioxidant peptides by hydrolyzing sesame 11 S protein by single factor and response surface test were as follows: enzyme content 10000 u/g protein,substrate concentration 3 %,hydrolysis p H 8.60,temperature 44.81 ℃,time 1.96 h.Under these conditions,the yield of the polypeptide was(77.41±0.30)%,the total antioxidant capacity is(1.40±0.02)mmol/L,the IC50 of DPPH and ABTS radical scavenging capacity were 1.41 mg/m L and 1.06 mg/m L.According to the results of Ultrafiltration separation,Molecular weight under 3 k Da component has better oxidation resistance,the IC50 of DPPH and ABTS radical scavenging capacity were decreased by 12.77 %,10.38 %.The results of HPLC separation show that The best antioxidant components,The total antioxidant capacity was(1.72±0.03)mmol/L,the IC50 of DPPH and ABTS radical scavenging capacity were 0.99 mg/m L and 0.85 mg/m L.Finally,collected and concentrated,freeze-dried.To obtain the target extract of Sesame 11S Protein Antioxidant Peptide.