Separation of Casein Enzymatic Hydrolysate and Its Antioxidant Activities

Casein was hydrolyzed by three ways,pepsin(P),trypsin(T),pepsin and trypsin(P+T). The hydrolysate(P+T)was separated by cation exchange resin of 001 to obtain casein peptides. The antioxidant activities of casein peptides and P+T were measured,compared with the casein hydrolysate by pepsin(P)or trypsin(T). The results showed that casein peptides were separated originally by 001 resin and four peptides were gained and named P1,P2,P3,P4. The reducing power and DPPH radical scavenging capacity of P1,P2,P3,P4 were significantly higher than P,T and(P+T). P4 had higher Fe²⁺ chelating capacity than others,which was 94.95%. The Fe²⁺ chelating capacities of P,T and(P+T)were similar,in the range of 31%~33%. However,the peptides of P1,P2,P3 did not have Fe²⁺ chelating capacity. P had the best inhibition capacity on lipid peroxidation,followed by T. P1,P2,P3,P4 and(P+T)did not show that capacity on lipid peroxidation. In conclusion,peptides could be gained by cation exchange resin from(P+T),which had high radical scavenging capacity and Fe²⁺ chelating capacity. The results could provide the references for process and separation of casein antioxidant peptides.