不同品种原料乳理化特性分析

主要分析荷斯坦牛、牦牛、娟珊牛、摩拉水牛、尼里-拉菲水牛、Ⅰ代杂交水牛、高代杂交水牛等7个品种的原料乳的常规营养成分，并对原料乳中蛋白质和氨基酸组成及牛乳缓冲能力进行测定。结果显示：摩拉水牛、尼里-拉菲水牛、Ⅰ代杂交水牛和高代杂交水牛的乳脂肪含量分别为6.86%、7.99%、8.34%、8.69%，蛋白质含量分别为5.75%、5.14%、5.78%、5.58%，干物质含量分别为17.07%、18.79%、19.73%、19.88%，显著高于其他3种牛乳；牦牛和娟珊牛乳中乳糖含量分别为5.09%、5.17%，显著高于其他5种牛乳。SDS-PAGE显示：水牛乳中除含有牛乳血清蛋白(BSA)、α-酪蛋白(α-CN)、β-酪蛋白(β-CN)、κ-酪蛋白(κ-CN)、β-乳球蛋白(β-Lg)和α-乳白蛋白(α-La)主要蛋白外，还含有一些未定性蛋白；且水牛乳具有最好的缓冲性能，其次是牦牛乳和娟珊牛乳，荷斯坦牛乳缓冲性能最差。

Analysis of Physico-chemical Properties of Raw Milk of Cattle,Buffalo and Yak

In this study, proximate nutrients of raw milk of Holstein, yak, Jersey cattle, Murrah buffalo, Nili-Ravi buffalo,hybrid F1 buffalo and multiple-generation hybrid buffalo were analyzed, and the contents of proteins and amino acidsas well as the buffer capacity of milk was determined. The results showed that the fat, protein and total solid contents inMurrah, Nili-Ravi, hybrid F1 and multiple-generation hybrid buffalo milk were 6.86%, 7.99%, 8.34%, 8.69%, 5.75%, 5.14%,5.78%, 5.58%, and 17.07%, 18.79%, 19.73% and 19.88%, respectively, all of which were significant higher than those inanother three kinds of raw milk. The lactose contents of yak and Jersey were 5.09% and 5.17%, which were significantlyhigher than those in another five kinds of raw milk. SDS-PAGE showed that milk protein in buffalo had unknown bandsexcept BSA, α-CN, β-CN, κ-CN, β-Lg and α-La. The buffalo milk revealed the best buffer capacity, which was followed byyak and Jersey milk, and Holstein milk exhibited the lowest buffer capacity.