酪蛋白酶解物的分离及其抗氧化活性

采用胃蛋白酶和胰蛋白酶(P+T)先后连续水解酪蛋白,采用001阳离子交换树脂分离该酶解液得到多肽;以酪蛋白的单一胃蛋白酶(P)和单一胰蛋白酶(T)酶解液为对照,系统评价酪蛋白不同酶解液及分离所获得的酪蛋白多肽的抗氧化活性。结果表明,阳离子交换树脂对(P+T)酶解液具有较好的分离作用,洗脱曲线共有4个峰,分别为P1、P2、P3、P4,收集冻干制得4个多肽。抗氧化性评价显示,P1、P2、P3、P4的还原力和DPPH自由基清除能力远高于未经分离的P、T和(P+T)酶解液。多肽P4表现出极高的Fe²⁺螯合能力,螯合率高达94.95%;P、T和(P+T)酶解液的Fe²⁺螯合力相当,螯合率达31%～33%,而P1、P2、P3不具备Fe²⁺螯合能力。在脂质过氧化抑制方面,P酶解液表现出较好的抑制力,其次为T酶解液,多肽P1、P2、P3、P4及(P+T)不具有脂质过氧化抑制力。由此可见,(P+T)连续水解液经阳离子交换树脂分离可制备具有较高自由基清除力及Fe²⁺螯合力的肽段,研究结论可为酪蛋白抗氧化肽的制备及分离提供参考依据。

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 Fe^2+chelating capacity than others,which was 94.95%.The Fe^2+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 Fe^2+chelating capacity.The results could provide the references for process and separation of casein antioxidant peptides.