酶解与体外模拟胃肠消化对脱脂羊奶粉ACE抑制活性的影响

Effect of Enzymolysis and in Vitro Simulated Gastrointestinal Digestion on the ACE Inhibitory Activity of Defatted Goat Milk Powder

本研究旨在探究商业蛋白酶酶解与体外模拟胃肠消化对高消化率的脱脂羊奶粉释放ACE抑制肽的影响,以评价脱脂羊奶粉酶解必要性及所需酶解程度。采用中性蛋白酶、碱性蛋白酶、复合蛋白酶和风味蛋白酶对脱脂后的圭山羊奶粉进行酶解反应,并对脱脂羊奶粉及其酶解物进行体外模拟胃肠消化,测定酶解液及模拟胃肠消化液的多肽含量、ACE抑制活性以及分子量分布。研究发现,羊奶粉经过体外模拟胃肠消化后,消化液的多肽含量与ACE抑制率分别达到20.81 mg/mL和62.55%;而经过碱性蛋白酶和风味蛋白酶的适度酶解,其模拟胃肠消化液多肽含量与ACE抑制活性反而下降;经过复合蛋白酶的适度酶解,其模拟胃肠消化液的多肽含量与ACE抑制活性小幅度提高,分别达到22.67 mg/mL和69.29%;经过中性蛋白酶的适度酶解,其模拟胃肠消化液多肽含量与ACE抑制活性均显著提高,分别达到23.76 mg/mL和81.10%。分子量分布结果显示,经过体外模拟胃肠消化后,<1000 Da的小分子肽由酶解液中的70.77%提高到90%。综上,圭山羊奶粉经过体内胃肠消化就可以释放出较多的ACE抑制肽,而经过中性蛋白酶酶解至水解度8%后,ACE抑制活性还可以再提升28.83%,因此在一定程度上具有进一步酶解的必要性。

This study aimed to investigate the effect of commercial protease enzymolysis and in vitro simulated gastrointestinal digestion on the release of ACE inhibitory peptides from the defatted goat milk powder with high digestibility,and to evaluate the necessity and the extent of enzymatic hydrolysis.Neutrase,alcalase,protamex,and flavourzyme were used for the enzymolysis of the defatted Kuishan goat milk powder.The goat milk and its enzymatic hydrolysates were further digested via simulated gastrointestinal digestion in vitro.The peptide content,ACE inhibitory activity and molecular weight distribution of the enzymatic hydrolysates and the simulated gastrointestinal digests were determined.Results showed that after the simulated gastrointestinal digestion in vitro,the peptide content and ACE inhibitory activity of the goat milk powder digests were 20.81 mg/mL and 62.55%,respectively.However,after moderate enzymatic hydrolysis by alcalase and flavourzyme,the peptide content and ACE inhibitory activity of simulated gastrointestinal digests decreased.After moderate enzymolysis by protamex,the peptide content and ACE inhibitory activity of simulated gastrointestinal digests were increased slightly to 22.67 mg/mL and 69.29%,respectively.After moderate enzymolysis by neutrase,the peptide content and ACE inhibitory activity of simulated gastrointestinal digests were significantly increased to 23.76 mg/mL and 81.10%,respectively.The molecular weight(MW)distribution results showed that after in vitro simulated gastrointestinal digestion,the amount of the small molecular peptides with MW<1000 Da increased from 70.77%to 90%.Above results indicate that Kuishan goat milk powder can exert ACE inhibitory activity after gastrointestinal digestion,and the ACE inhibitory activity can be further increased by 28.83%after neutral protease hydrolysis to degree of hydrolysis of 8%.Therefore,it was necessary to further enzymatic hydrolysis to a certain extent.