Abstract: In this study, white yak’s milk samples from three pastoral areas in Tianzhu county, Gansu province, collected at four different growth stages (withering, the final stage of withering, reviving and green) of forage grasses as well as from female yaks of different parity were analyzed by GC–MS for fatty acid composition. The results showed no significant difference in fatty acid content of yak’s milk among three pastoral areas or among 5 parities (P ＞ 0.05). The SFA:USFA ratio of yak’s milk at the withering stage, the final part of withering, the reviving stage and the green stage was 1.86, 1.75, 1.62 and 1.32, respectively. Lower amounts of SFAs but higher amounts of USFAs were found in white yak’s milk as the temperature increased and forage became more mature.

Key words: yak’s milk；milk fat；fatty acids；gas chromatography–mass spectrometer (GC–MS)

摘要： 以甘肃天祝地区3个牧场所产的白牦牛乳为研究对象,采用气相色谱-质谱联用检测方法,测定3个牧场所产白牦牛乳中脂肪酸含量,比较在枯草期、枯草末期、返青期、青草期4个时期及不同胎次的白牦牛所产牦牛乳中脂肪酸的构成及含量.结果表明:3个牧场白牦牛乳中乳脂肪酸含量差异不显著(P＞0.05)；1～5胎次母白牦牛乳中脂肪酸含量差异不显著(P＞0.05).枯草期、枯草末期、返青期、青草期4个时期白牦牛乳中饱和脂肪酸(SFA)、不饱和脂肪酸(USFA)含量比值分别为1.86、1.75、1.62、1.32.随着气温的升高及牧草的成熟,白牦牛乳中饱和脂肪酸含量逐渐降低,而不饱和脂肪酸的含量逐渐升高.

关键词: 白牦牛乳；乳脂肪；脂肪酸；气相色谱-质谱联用