Protein composition of yak milk

The protein composition of 24 individual Maiwa yak milk samples that were collected in the Sichuan province of China was determined by reversed-phase high-performance liquid chromatography. Yak milk differed from cow milk by its high concentration of total proteins (46.2– 58.4 g·L), total casein (40.2 g·L on average) and the proportion of individual caseins. The high content of β-casein (more than 45%) and consequently the lower proportion of αs-casein (about 40%) together with a small increase in κ-casein (15%) appear to make this milk more favorable for infant nutrition as used by the Tibetan nomads. Also, the whey proteins, β-lactoglobulin and serum albumin, showed similarities in centesimal composition with the homologous cow whey proteins. However, this initial study on yak milk proteins has highlighted the lack of knowledge in the literature and underlines that much research is required to optimize the utilization of all components of this milk for people living in extreme climatic environments. yak milk / casein / whey protein / HPLC 摘要 – 牦牛乳的蛋白质组成○ 采用 RP-HPLC 方法,对中国四川省麦洼地区的 24 个牦牛乳 样品蛋白质的组成进行了分析○ 牦牛乳与牛乳相比,在总蛋白质含量 (46.2–58.4 g·L)、总 酪蛋白质含量 (40.2 g·L) 和各酪蛋白在总酪蛋白所占的比例方面都存在较大的差异○ 牦牛 乳中 β-酪蛋白在总酪蛋白中的含量很高 (大于 45%),而 αs-酪蛋白约占总酪蛋白的 40%,κ-酪 蛋白约占总酪蛋白的 15%○ 牦牛乳酪蛋白的组成非常适合婴幼儿的营养需要,中国西藏少数 民族地区的人们也通常用牦牛乳来哺育婴幼儿○ 牦牛乳中 β-乳球蛋白和血清白蛋白的组 成与牛乳相似○ 目前关于牦牛乳蛋白质组成方面的知识及可参考的文献非常少,并且为了 使生活在极端环境条件下的人们能更好地开发利用牦牛乳,应该加强并深入对牦牛乳的