Study On Preparation Of Antioxidant Peptide From Safflower Seed Protein And Its Application

Safflower production in China ranks the top in the world,and safflower processing enterprises emerge one after another,but they mainly focus on the development of safflower seed oil,and 25%?40%of the high-quality plant protein resources in safflower seed meal,a by-product of safflower processing,have not been reasonably and efficiently utilized.Food-derived peptides have the advantages of high safety,low production cost,easy absorption and a variety of functional activities,so safflower seed peptides have broad market prospects.In this study,safflower seed protein was extracted from safflower seed meal,and safflower seed antioxidant peptides were prepared by compound enzymatic hydrolysis with antioxidant activity and hydrolysis degree as evaluation indexes.The stability of antioxidant activity of polypeptides with different molecular weights was studied.The polypeptide components with high activity and strong stability were obtained,and the antioxidant activity of polypeptides in vivo was studied by mouse model.Finally,a functional polypeptide beverage was developed with safflower seed antioxidant peptides as the main raw materials.The main results are as follows:(1)The compound protease was screened by the degree of hydrolysis(DH)and the scavenging rate of many kinds of free radicals.Through single factor test and response surface optimization of compound enzymatic hydrolysis process,the best enzymatic hydrolysis conditions were obtained as follows:substrate concentration 5%,p H 8.0,alkaline protease?neutral protease 2?1,temperature 50?,enzyme addition 7000 U/g,hydrolysis 2 h.The DPPH radical scavenging rate of safflower seed protein hydrolysate was 75.66%.(2)The stability of strong antioxidant components(<3 k Da,3?5 k Da)after ultrafiltration separation of safflower seed protein hydrolysate was studied.The results showed that both groups could maintain free radical scavenging rate under high temperature,weak acid and weak alkali environment.The addition of Na Cl,citric acid and glucose had synergistic effect on free radical scavenging rate,but sucrose and preservatives had no significant effect.Metal ions such as Zn²⁺,Cu²⁺and K⁺significantly decreased the antioxidant activity of the two components.After simulated gastrointestinal digestion.Antioxidant peptides<3 k Da were more stable,and the effect of gastric digestion on antioxidant activity was less than that of intestinal digestion.(3)The experiment of oxidative damage induced by safflower seed antioxidant peptide(<3 k Da)in mice showed that the body weight of the mice increased steadily during the whole cycle,and there were significant differences between the model group and the normal group.The safflower seed antioxidant peptide group could significantly improve the organ index of the mice compared with the model group.Compared with the model group,each test group could significantly increase the activities of total antioxidant capacity(T-AOC),and antioxidant enzymes in serum,liver and heart,and decrease the content of malondialdehyde(MDA)in mice.There was no significant difference between safflower seed antioxidant peptide high dose group and Vc group,which could reduce oxidative stress and promote the growth and metabolism of mice.(4)The best proportion of safflower seed antioxidant peptide beverage products was0.1%of edible salt,0.1%of potassium sorbate,0.2%of carboxymethyl cellulose-Na(CMC-Na),8%of sweetener(sucrose?glucose=1?3),0.4%of citric acid and 10%of safflower seed antioxidant peptide.The sensory score of antioxidant peptide beverage was 95.17.