以牡丹籽粕为原料,用酶解法制备ACE抑制肽及其稳定性研究。以血管紧张素转化酶(angiotension converting enzyme,ACE)抑制率为指标,从中性蛋白酶、碱性蛋白酶、胃蛋白酶、胰蛋白酶和风味蛋白酶中筛选出最佳ACE抑制肽制备酶为中性蛋白酶。以单因素实验为基础,进行酶解条件的响应面优化,结果显示牡丹籽ACE抑制肽酶法制备的最优条件为:底物浓度2%,pH7.5,加酶量7200 U/g,酶解温度43℃,酶解时间2 h,此时酶解液ACE抑制率可达到86.93%±2.38%。此外,稳定性分析显示该ACE抑制肽具有良好的温度和酸碱稳定性,在温度20~100℃与pH2~10的环境下,ACE抑制活性没有显著变化(P>0.05),并且经过体外胃肠模拟消化后,ACE抑制活性变化不显著(P>0.05),仍能保持良好的抑制活性。
Angiotensin converting enzyme(ACE)inhibitory peptides were prepared by hydrolyzing peony seed meal and its stability was analyzed. Neutral protease hydrolysates were found to have the highest ACE inhibitory activity. Based on the results of single factor experiments,the hydrolysis conditions were optimized by the response surface methodology. The results showed that the optimum conditions for the preparation of ACE inhibitory peptides from peony seed meal were as follows:The concentration of substrate was 2%,pH7.5,dosage of enzyme was 7200 U/g,the temperature was 43℃,enzyme hydrolysis time was 2 h. The ACE inhibition rate of enzymatic hydrolysates could reach 86.93%±2.38% under these conditions. Meanwhile,the ACE inhibitory peptides had good resistance to temperature,acid and alkalinity. The ACE inhibitory activity did not change significantly(P>0.05)at the temperature of 20~100℃ and pH of 2~10(P>0.05).After simulated gastrointestinal digestion in vitro,the ACE inhibitory activity did not change significantly(P>0.05),and it still maintained a good inhibitory activity.