采用胃蛋白酶体外消化法和HPLC法测定了茶多酚与牛奶蛋白互作后蛋白质的离体消化率和几种主要儿茶素含量的变化,并用酒石酸铁比色法测定了两者互作后不同结合状态茶多酚的含量。结果表明:在牛奶蛋白含量为0.5%、茶多酚含量在0-10.0 g/kg的模拟奶茶溶液中,蛋白质的离体消化率随茶多酚浓度的增大而下降,茶多酚含量≥2.0 g/kg时牛奶蛋白的离体消化率显著降低;等体积的纯牛奶和茶水同时食用时,茶水中茶多酚含量≥2.5 g/L时牛奶蛋白的离体消化率显著降低。实验结果还表明,食用条件下茶多酚与牛奶蛋白的结合以物理结合为主,而其中EGCG和ECG 2种儿茶素与牛奶蛋白有较强的反应活性,对牛奶蛋白的离体消化率起主要影响作用。

Changes in vitro protein digestibility and contents of catchins in the system of tea polyphenol with milk protein was investigated.The results showed that in the model milk tea which contains 0.5 % milk protein and 0-10.0 g/kg tea polyphenols,the in vitro digestibility of the protein decreased as tea polyphenols content increased.It decreased significantly when the contents of tea polyphenols was more than 2.0 g/kg.When milk and tea mixed together at the same ratio and polyphenols was more than 2.5 g/L,the milk protein digestibility decreased significantly.The results also indicated that the interaction of tea polyphenols with milk protein was mainly physical interaction.The two catechins,EGCG and ECG had higher affinity with milk protein and had major affects on the in vitro digestibility of milk protein.