探讨牛乳粉中酪蛋白和乳清蛋白的糖基化程度及其水解特性。采用不同方法提取牛乳粉中的酪蛋白和乳清蛋白，SDS3PAGE电泳分析其组成；高碘酸-希夫碱染色法及莫氏试验检测糖基化的酪蛋白和乳清蛋白；木瓜蛋白酶水解牛乳和乳粉中的酪蛋白和乳清蛋白。鞣酸提取酪蛋白的质量分数46.13%显著高于其他方法(p<0.05)，乳酸发酵法是提取乳清蛋白的有效方法；电泳结果表明，酪蛋白有分子质量为24、34和60 ku的3条带，乳清蛋白有分子质量为14和18 ku的2条带；高碘酸-希夫碱糖蛋白染色结果表明，分子质量为24 和34 ku的酪蛋白和分子质量为14 ku的乳清蛋白均是糖基化蛋白；莫氏试验结果表明，乳粉中存在糖基化的酪蛋白和乳清蛋白；乳蛋白木瓜蛋白酶水解结果表明，乳粉酪蛋白和乳清蛋白水解游离氨基酸含量均显著低于鲜乳(p<0.05)。牛乳粉中存在糖基化的酪蛋白和乳清蛋白，前者分子质量分别为24和34 ku，后者为14 ku；乳粉中乳蛋白水解程度较鲜乳低。

The glycosylation of casein and whey protein in milk powder and its enzymatic hydrolysis property were studied. The casein and whey protein in milk powder were extracted by different methods. The compositions of casein and whey protein were analyzed by SDS-PAGE electrophoresis, and glycosylated casein and whey protein were identified by periodate-schiff alkali dyeing and Morse experiment. Amino acid content was determined after papain hydrolysis of casein and whey protein in milk powder and fresh milk. The results showed that the percentage of casein extracted by tannic acid was 46.13%, which was significantly higher than that of other groups (p<0.05). The method of lactic acid fermentation was the most efficient method to extract whey protein. The results of SDS-PAGE showed that the molecular weights of the casein and whey protein were 24, 34, and 60 ku, and 14 and 18 ku, respectively. The casein of 24 and 34 ku, and the whey protein of 14 ku were both glycoproteins by periodate-schiff alkali dyeing. The results of Morse experiment of casein and whey protein showed that milk powder exist glycoprotein. The results of milk protein hydrolysis by papain showed that the content of free amino acid in casein dehydrated from milk powder was significantly lower than that from fresh milk (p<0.05), and the same results to that of whey protein. Milk powder contained glycosylated casein, they were 24 and 34 ku of casein and 14 ku whey protein. The degree of milk protein hydrolysis from milk powder is lower than that from fresh milk.