以西农萨能奶山羊和荷斯坦牛为对象,研究山羊乳和牛乳挥发性游离脂肪酸组成的差异,并分析其分子机理.采用固相微萃取/GC-MS分析二者挥发性游离脂肪酸组成,对西农萨能奶山羊脂肪酸合成酶乙酰-CoA/丙二酰-CoA转移酶区域(AT-MT) cDNA克隆,对其AA序列及蛋白二级结构与荷斯坦牛进行比较.结果表明西农萨能奶山羊奶中癸酸(40.89 g/100 g)是影响其风味的主效成分.西农萨能奶山羊AT/MT AA序列、蛋白二级结构与荷斯坦牛存在明显差异.西农萨能奶山羊脂肪合成与代谢相关酶基因应是羊奶膻味形成的关键因素,传统育种和分子育种方法将是提高山羊乳品质的有效途径.%In this mansucript, the milk from Xinong Saanen goat and Holstein cattle was used as the research model to investigate the volatile free fatty acid composition and to elucidate the molecular mechanism. Volatile free fatty acids were extracted by solid-phase microextraction (SPME), were analyzed by gas chromatograph combination with mass spectrophotometer (GO MS). The AT-MT gene sequence of fatty acid synthase from Xinong Saanen goat was cloned, and the AA sequence and protein secondary structure distribution were compared with that of Holstein cattle. The results showed that n-Decanoic acid was the main effect flavor component (40. 89%) in Xinong Saanen goat, there were significant differences in AA sequence and proteinsecondary structure distribution between Xinong Saanen goat and the cattle. It demonstrated thatfat enzyme gene of synthesis and metabolism was responsible for goaty flavor, and breedingmethods of tradition and molecular could be effective ways to improve goat milk quality.
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