基于GC-MS技术的水牛乳与奶牛乳中长链脂肪酸组成差异分析及掺假识别方法初探

Analysis of the Difference in Long Chain Fatty Acid Composition Between Buffalo Milk and Cow Milk Based on GC-MS Technology and Research on the Identification Method of Adulteration

摘要:

乳脂及乳脂肪酸组成是评价乳的营养价值和功能品质的重要指标,利用气相色谱-质谱法(GC-MS)比较水牛乳跟奶牛乳脂肪酸的组成及含量的差异,旨在筛选出区分两种品种牛乳的标志性化合物。结果表明：共检测出两类乳样品中存在50种脂肪酸,利用正交偏最小二乘判别分析(Orthogonal Partial Least Squares Discriminant Analysis, OPLS-DA)和热图对两种乳的中长链脂肪酸进行了聚类分析,发现基于脂肪酸组成特征能够将水牛乳和奶牛乳显著区分。结合OPLS-DA筛选出23种VIP＞1的差异脂肪酸化合物,其中,水牛乳中有13种差异性脂肪酸的含量显著高于奶牛乳(P＜0.05),这13种物质可作为水牛乳潜在特征性脂质成分。基于以上特征性脂肪酸分析,建立了2种动物乳的中长链脂肪酸的指纹图谱,对乳脂肪酸组成进行差异性分析,找到双指标C13:0/C22:5n-6,C14:1/C22:5n-6特征脂肪酸比值作为差异性指标。基于此比值,建立了一套水牛乳中双指标判定方法用于奶牛乳的掺假识别。

Abstract:

Milk fat and milk fatty acid (FA) compositions are important indicators for evaluating the nutritional value and functional qualities of milk, Gas chromatography-mass spectrometry (GC-MS) was utilized to compare the differences in fatty acid composition and content between buffalo milk and cow milk, with the aim of screening for signature compounds that distinguish the two varieties of cow milk. The results showed that a total of 50 fatty acids were detected in the two types of milk samples, and the medium and long chain fatty acids of the two milks