基于超声预处理的脱脂玉米胚芽ACE抑制肽的制备

为了研究超声辅助酶解制备血管紧张素转化酶(ACE)抑制肽的较优工艺,通过三种超声设备对脱脂玉米胚芽预处理,碱性蛋白酶酶解,酶解液体外模拟胃肠消化,以消化液ACE抑制率和酶解过程中玉米胚芽水解度(DH)为指标对超声预处理和酶解的参数进行单因素逐级优化。实验结果表明,最佳超声工作模式为20~40 kHz聚能式逆流双频交替超声模式;超声工作参数为功率密度120 W/L,超声预处理时间15 min,初始温度30℃,物料浓度5%;酶解条件为加酶量3000 U/g,酶解时间30 min,pH9.0,酶解温度50℃。在此条件下,酶解液的IC₅₀为4.166 mg/mL,比对照组降低了5.08%;胃肠消化液的IC₅₀为3.986 mg/mL,比对照降低了4.44%。制备的酶解产物,经模拟胃肠消化后具有较强的ACE抑制活性。优化获得的制备脱脂玉米胚芽ACE抑制肽的工艺是可行的。

Preparation of ACE Inhibitory Peptide from Defatted Corn Germ Based on Ultrasonic Pretreatment

The superior preparation parameters of angiotensin converting enzyme(ACE)inhibitory peptide were studied by ultrasonic assisted enzymolysis. Defatted corn germ was pretreated under three kinds of ultrasonic equipment,and hydrolyzed by alcalase. The enzymatic hydrolysate was digested in vitro. ACE inhibitory activity of gastrointestinal digestive hydrolysate and degree of hydrolysis(DH)of corn germ in enzymatic hydrolysis process were taken as the indexes for searching for the optimal parameters of ultrasound pretreatment and enzymolysis. The results showed that the best ultrasonic working mode was 20~40 kHz dual-frequency ultrasound,power density was 120 W/L,ultrasound pretreatment time was 15 min,initial temperature of the suspension was 30℃ and substrate concentration was 50 g/L. And enzyme dosage was 3000 U/g,enzymolysis time was 30 min,pH was 9.0 and enzymolysis temperature was 50℃. Under optimal conditions,the enzymatic hydrolysates value of IC₅₀ was 4.166 mg/mL,decreased by 5.08% compared with control. The gastrointestinal digestive hydrolysate value of IC₅₀ was 3.986 mg/mL,decreased by 4.44% compared with control. The gastrointestinal digestive hydrolysate had stronger ACE inhibitory activity. The optimization technology of preparation ACE inhibitory peptide from defatted corn germ was feasible.