母乳、牛乳与主要小品种乳蛋白质组成及乳清蛋白二级结构比较

Comparative study on the composition of protein and secondary structure of whey protein in human milk, milk and main small varieties of milk

中文关键词:  母乳  小品种乳  乳清蛋白  蛋白二级结构

英文关键词:human milk  small varieties of milk  whey protein  secondary structure of protein

中文摘要:

      目的 对比母乳、牛乳、山羊乳、绵羊乳、驼乳和驴乳的蛋白质组成及乳清蛋白二级结构, 厘清主要加工乳种与母乳的蛋白质差异。方法 通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(sodium dodecyl sulfate-polyacrylamide gel electrophoresis, SDS-PAGE)和傅里叶变换红外光谱法(Fourier transform infrared spectroscopy, FTIR)对比各乳种的蛋白质组成和乳清蛋白二级结构。结果 绵羊乳中蛋白质、乳糖、脂肪含量均显著高于母乳、牛乳、山羊乳、驼乳和驴乳(P<0.05), 母乳中蛋白质、乳糖、矿物质与驴乳各对应指标均无显著性差异(P>0.05); 检测结果母乳酪蛋白:乳清蛋白(C:W)为38.58:61.42, 牛乳C:W为81.43:18.57, 山羊乳C:W为61.14:38.86, 绵羊乳C:W为68.42:31.58, 驼乳C:W为56.16:43.84, 驴乳C:W为8.91:91.09; 母乳与驼乳均含有较高的乳铁蛋白与血清白蛋白, 几乎不含β-乳球蛋白, 且乳清蛋白的α?螺旋结构占比较高。结论 母乳与主要加工乳种蛋白质组成与乳清蛋白二级结构不尽相同, 该研究为各种乳源高值化利用和纯度鉴别提供了参考依据。

英文摘要:

      Objective To compare the composition of protein and secondary structure of whey protein in human, cow, goat, sheep, camel, donkey milk and clarify the differences between human milk and main proceeded milk. Methods The composition of protein and secondary structure of whey protein in different milk were investigated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Fourier transform infrared spectroscopy (FTIR). Results The content of lactose, fat and protein in sheep milk was significantly higher than that of human, cow, goat, camel and donkey milk (P<0.05), there was no significant difference in the content of lactose, protein and mineral between human milk and donkey milk (P>0.05). The results showed that the casein:whey protein (C:W) of human milk was 38.58:61.42, the C:W of cow milk was 81.43:18.57, the C:W of goat milk was 61.14:38.86, the C:W of sheep milk was 68.42:31.58, the C:W of camel milk was 56.16:43.84, and the C:W of donkey milk was 8.91:91.09. The content of lactoferrin and serum albumin in human and camel milk was high, they contained no β-lactoglobulin and high ratio of α-helix structure. Conclusion There are differences in the composition of protein and secondary structure of whey protein in human milk and main proceeded milk, which can provide a theoretical basis for high-value utilization and purity identification of different milks.