Abstract: In this study, the effect of thermal modifications (25, 75, 85 and 95 ℃ for 15 min) on the structure and digestibility of milk protein concentrate (MPC70) was evaluated. Results shows that the free sulfhydryl content and surface hydrophobicity increased significantly with temperature up to 95 ℃, reaching the highest value of 42 μmol/L and 1 008, respectively. The contents of α-helix and β-turns decreased, while the contents of β-sheet and random coil increased. sodium dodecyl sulfate polyacrylamide gel electrophoresis after simulating gastrointestinal revealed that a certain degree of heat treatment enhanced the digestibility of milk proteins, which may be attributed to structural changes.

Key words: milk protein; structure; heat treatment; modification; digestibility

摘要： 通过热处理对浓缩乳蛋白70（milk protein concentrate 70，MPC70）进行改性，研究改性对乳蛋白结构及 消化性的影响。结果表明：乳蛋白经过25、75、85、95 ℃分别处理15 min，随着热处理温度的增加，表面巯基含量 和表面疏水性显著升高，在95 ℃时达到最高，分别为42 μmol/L和1 008；经过热处理后，乳蛋白中α-螺旋和β-转角 的含量下降，β-折叠和无规则卷曲含量上升；通过采用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分析模拟胃肠消化样 品发现，一定程度的热处理提升了乳蛋白的可消化性，这可能与其结构变化相关。

关键词: 乳蛋白；结构；热处理；改性；消化性