Preparation of antioxidant peptide from walnut protein by enzymatic hydrolysis

It was studied that the technique of the enzymatic hydrolysis of walnut to prepare the peptide with low-molecular weights,antioxidant activities of which were also determined.The optimum hydrolysis conditions(pH8.5,temperature 50℃,the ratio of enzyme concentration to substrate concentration [E]/[S]=3:100,substrate concentration[S]=3.5g/100mL,time 5h)were obtained through single factor test and orthogonal test.Walnut peptides were isolated into 3 parts by ultrafiltration membranes with 3kDa MWCO(Molecular Weight Cutoff),10kDa MWCO respectively.The antioxidant activities of different parts of walnut peptides were studied,which revealed that the part of walnut peptides with molecular weight 3kDa showed the best antioxidant activities.