酶解玉米胚芽粕制备ACE抑制肽的条件优化

Optimization of preparation of ACE inhibitory peptides by hydrolysis of corn germ meal

采用碱性蛋白酶酶解玉米胚芽粕制备血管紧张素转化酶(ACE)抑制肽,并以ACE抑制率为指标,在单因素的基础上,通过L9(34)正交试验来确定酶解的最佳工艺条件。最佳酶解条件为:底物浓度5%(w/v)、加酶量3%(w/w)、温度60℃、pH 8.5、水解时间2.5 h,在此条件下,水解物对ACE抑制作用最强,抑制率可以达到86.38%(此时水解度为22.76%)。以截留分子量为6KDa的超滤膜分离该水解物,测定两组分的ACE抑制活性。酶解液经超滤后组分Ⅱ(M<6 kDa)的IC50值达到1.38 mg/mL,优于未超滤的酶解液的IC50值(3.16 mg/mL)。

Corn germ meal was hydrolyzed by alkaline protease to prepare ACE inhibitory peptides. Based on the single -factor experiments, the orthogonal experiment of L9 （34） was used to optimize enzymatic conditions and the ACE inhibitory rate was used as the indicator. The optimal condition was as follows： substrate concentration was 5 % （ w/v）, enzyme concentration 3 % （ w/w）, temperature 60 ℃, pH 8.5, hy- drolysis time 2.5 h. Under the condition the inhibition of the hydrolysate against ACE was the strongest, the inhibitory rate was 86.38% and the degree of hydrolysis was 22.76%. The hydrolysate was separated by the ultrafihration membrane with the molecular weight cutoff 6 KDa. The inhibitory activities of the two fractions were determined. The 50% inhibitory concentration（IC50） of fraction Ⅱ （ M 〈 6 kDa） was 1.38 mg/mL,which was better than that of the un -uhrafiltration fraction（3.16 mg/mL）.