青海牦牛乳脂肪Sn-2位脂肪酸组成分析

Composition of Sn-2 fatty acids in yak milk fat from Qinghai province

以采自青海地区不同海拔高度的的牦牛乳脂肪为研究对象,利用气相色谱仪及薄层层析法测定牦牛乳脂肪的Sn-2位脂肪酸的组成,并研究不同海拔高度的牦牛乳脂肪的Sn-2位脂肪酸组成是否存在显著性差异,并分析其原因。结果表明青海牦牛乳脂肪的甘油三酯的总脂肪酸共有12种,含量较高的为棕榈酸(31.35%~36.48%),油酸(24.91%~30.99%)和硬脂酸(9.82%~13.87%)。青海牦牛乳脂肪的Sn-2位脂肪酸组成为:己酸(0.66%~1.02%),癸酸(2.46%~3.98%),月桂酸(2.43%~4.88%),十四烷酸(14.66%~20.68%),十五烷酸(1.19%~1.76%),棕榈酸(39.91%~46.23%),棕榈油酸(2.81%~5.35%),硬脂酸(4.75%~8.31%),油酸(17.42%~20.81%),亚油酸(0.00%~1.72%),亚麻酸(0.00%~1.71%)。显著性分析显示:随着海拔的升高,结合在牦牛乳甘油三酯Sn-2位上的饱和脂肪酸(SFA)占比先逐渐升高,后显著降低(P<0.05)。不饱和脂肪酸(UFA)的占比先逐渐降低,趋于平缓后显著升高(P<0.05)。

The composition of Sn-2 fatty acids in yak milk fat was determined by gas chromatograph and TLC. The Sn-2 fatty acid composition of yak milk fat at different altitudes was studied to determine the effect of different altitudes on triglyceride structure. The results showed that there were 12 kinds of total fatty acids of triglyceride in Qinghai yak milk fat, and the highest contents were palmitic acid (31.35%~36.48%), oleic acid ( 24.91%~ 30.99%) and stearic acid (9.82%~13.87%). The composition of Sn-2 fatty acids in Qinghai yak milk fat was as follows: hexanoic acid (0.66%~1.02%), decanoic acid (2.46%~3.98%), lauric acid (2.43%~4.88%), tetradecanoic acid ( 14.66%~ 20.68%), pentadecanoic acid (1.19%~1.76%), palmitoic acid (39.91%~46.23%), stearic acid (4.75%~ 8.31%), oleic acid (17.42%~20.81%), linoleic acid (0.00%~1.72%), and linolenic acid (0.00%~1.71%). The significance analysis showed that the proportion of saturated fatty acids (SFA) binding to the Sn-2 of yak milk triglycerides increased gradually with the elevation, then decreased significantly;the proportion of unsaturated fatty acids (UFA) decreased gradually at first, then decreased gradually and then increased significantly.