苦瓜皂苷与乳清蛋白水解物协同对二肽基肽酶-IV的抑制活性

为评价动植物源天然产物的二肽基肽酶-IV（dipeptidyl peptidase-IV，DPP-IV）抑制活性，以苦瓜皂苷（momordica saponins，MS）、乳清蛋白胃蛋白酶水解物（whey protein pepsin hydrolysates，WPPHs）、乳清蛋白胰蛋白酶水解物（whey protein trypsin hydrolysates，WPTHs）为原料，采用单因素试验和响应面分析优化水解条件，再将MS与WPPHs、WPTH进行复配，结合模拟体外消化，探究DPP-IV抑制活性。结果表明，MS、WPPHs及WPTHs具有DPP-IV抑制活性，最佳水解条件为：当酶添加量4%、pH 2.7酶解2 h时，WPPHs的DPP-IV抑制率最高为15.43%；当酶添加量4%、pH 7.6酶解4 h时，WPTHs的DPP-IV抑制率最高为14.62%。苦瓜皂苷与乳清蛋白水解物具有协同对二肽基肽酶-IV抑制活性作用，当MS与WPPHs、WPTHs的复配体积比均为1:1时，显著高于两者单独累加（p<0.05）。经胃消化后，WPPHs的DPP-IV抑制率降低2.02%，MS和WPTHs的DPP-IV抑制率升高0.99%、7.01%；经肠道消化后，WPPHs的DPP-IV抑制率升高2.23%，而MS和WPTHs的DPP-IV抑制率降低4.12%、2.70%。研究结果可为天然动植物源产物协同对二肽基肽酶-IV抑制活性提供了基础性数据，为降血糖功能性产品的开发提供新的方向。

Synergistic Inhibitory Activity of Momordica charantia Saponin and Whey Protein Hydrolysate on Dipeptidyl Peptidase-IV

To evaluate the inhibitory activity of dipeptidyl peptidase-IV (DPP-IV) from natural animal products, Momordica saponins (MS), whey protein pepsin hydrolysates (WPPHs), and whey protein trypsin hydrolysates (WPTHs) were used as raw materials, and the hydrolysis conditions were optimized by single factor test and response surface analysis, and then MS and WPPHs and WPTH were compounded, combined with simulated in vitro digestion, the inhibitory activity of DPP-IV was explored. The results showed that MS, WPPHs and WPTHs had DPP-IV inhibitory activity. The optimal hydrolysis conditions were as follows: When the enzyme was added at 4% and the pH was 2.7 for 2 h, the highest DPP-IV inhibitory rate of WPPHs was 15.43%; The highest DPP-IV inhibition rate of WPTHs was 14.62% when the addition amount was 4% and pH 7.6 was enzymatically hydrolyzed for 4 h. MS and whey protein hydrolysate had a synergistic effect on inhibitory activity of DPP-IV. When the combined volume ratio of MS, WPPHs and WPTHs is 1:1, it is significantly higher than that of their accumulation alone (p<0.05). After gastric digestion, the DPP-IV inhibition rate of WPPHs decreased by 2.02%, and the DPP-IV inhibition rate of MS and WPTHs increased by 0.99% and 7.01%, respectively; after intestinal digestion, the DPP-IV inhibition rate of WPPHs increased by 2.23%, while the DPP-IV inhibition rate of MS and WPTHs decreased by 4.12% and 2.70%, respectively. The results provide basic data for the synergistic inhibitory activity of natural animal and plant products against dipeptidyl peptidase-IV, and provide a new direction for the development of hypoglycemic functional products.