逆流超声辅助酶解法制备大米ACE抑制肽

研究逆流超声预处理大米蛋白对其碱性蛋白酶酶解制备血管紧张素转换酶(Angiotensin-I Converting Enzyme,ACE)抑制肽的影响。首先从米渣中提取大米蛋白,以ACE抑制率为主要指标,水解度为辅助指标,运用单因素逐级优化法对酶解反应的底物浓度、时间、温度、加酶量和pH进行参数优化,在此基础上筛选逆流超声模式的最佳超声参数。结果表明最佳酶解参数为底物浓度30 g/L、加酶量(E/S)7.5%、温度50 ℃、pH8.5和酶解时间60 min,此时酶解产物ACE抑制率为45.59%,水解度为21.49%。最佳超声参数为超声频率20 kHz、功率密度170 W/L、时间12.5 min。此时酶解液ACE抑制率达72.24%,水解度为21.64%,相较于未超声组ACE抑制率提高了57.42%,相较于传统超声组,ACE抑制率提高了11.36%。结果表明逆流超声波辅助酶解法能有效提高酶解效率、减少能耗、促进ACE抑制肽制备。

Preparation of rice ACE inhibitory peptide by countercurrent ultrasonic assisted enzymatic hydrolysis

The study investigated the effect of countercurrent ultrasound pretreatment of rice protein on the preparation of ACE peptides by enzymatic hydrolysis of alkaline proteases. First,the rice protein was extracted from the rice residue. With the ACE inhibition rate as the main index and the degree of hydrolysis as the auxiliary index,the single factor stepwise optimization method was used to optimize the substrate concentration,time,temperature and pH of the enzymatic reaction. On this basis,the optimal ultrasonic parameters of the countercurrent ultrasound mode were screened out. The results showed that the optimum conditions were as follows:substrate concentration was 30 g/L,enzyme dosage(E/S)was 7.5%,temperature was 50 ℃,pH was 8.5 and enzymolysis time was 60 min,under this conditions,the ACE inhibition rate was 45.59% and the degree of hydrolysis was 21.49%. The optimal ultrasonic parameters were as follows:ultrasonic frequency was 20 kHz,power density was 170 W/L,time was 12.5 min. Under this conditions,the inhibition rate of ACE was 72.24% and the degree of hydrolysis was 21.64%. Compared with the untreat group,the ACE inhibition rate increased by 57.42%. Compared with the traditional ultrasound group,ACE inhibition rate increased by 11.36%. The results showed that the countercurrent ultrasonic assisted enzymatic hydrolysis method could effectively improve the enzymolysis efficiency,reduce the energy consumption and promote the preparation of ACE inhibitory peptide.