Abstract: In order to explore the inhibitory effect of bioactive substances on the degradation of milk fat during simulated gastrointestinal digestion, the impact of bioactive substances on the in vitro digestibility of milk proteins was examined as well as the inhibitory effect on pancreatic lipase activity and the micellar solubility of cholesterol. The results showed that the in vitro digestibility of milk proteins was inversely proportional to the concentration of the tested bioactive compounds, which decreased from 90.94% to 68.37% and 86.00% with increasing concentration of epigallocatechin (EGC) and β-glucan, respectively. The inhibitory effect of EGC on pancreatic lipase activity decreased to different extents with increased amount of added milk proteins, and so did the inhibitory effect of β-glucan and a mixed solution of 2.5 g/L β-glucan, 3.0 g/L epigallocatechin gallate (EGCG) and 2.0 g/L EGC on the micellar solubility of cholesterol. The inhibitory effect of this mixture on the degradation of milk fat was stronger than that of β-glucan.

Key words: milk, protein digestibility in vitro, polyphenols, β-glucan

摘要： 以牛乳为材料，研究模拟胃肠道消化过程中活性物质对牛乳中蛋白质体外消化率、抑制胰脂酶活性及胆固醇胶束溶解度的影响。结果表明：牛乳蛋白质体外消化率与活性物质添加量成反比，随表没食子儿茶素（epigallocatechin，EGC）添加量增加，蛋白质体外消化率从90.94%降至68.37%，随β-葡聚糖添加量的增加，蛋白质消化率从90.94%降至86.00%；当体系中加入乳蛋白时，随着乳蛋白添加量的增大，EGC对胰脂酶活性的抑制率有不同程度下降，β-葡聚糖及功能性成分混合液（β-葡聚糖2.5 g/L、表没食子儿茶素没食子酸酯 3.0 g/L、EGC 2.0 g/L）对胆固醇胶束溶解度的抑制率下降。活性物质对牛乳降脂作用的影响为功能成分混合液＞β-葡聚糖。

关键词: 牛乳, 蛋白质体外消化率, 多酚, β-葡聚糖