美仁牦牛乳品质特性分析

Analysis of Milk Quality Characteristics in Meiren Yak

为深入开发利用美仁牦牛乳产品,2022年5月份采集了10头美仁牦牛的乳样,采用乳成分测定仪、全自动氨基酸分析仪、气相色谱仪和风味分析仪等对其常规营养成分、氨基酸、脂肪酸和挥发性风味物质含量进行检测。结果表明,美仁牦牛乳的主要营养成分含量为脂肪6.43%,蛋白质5.45%,乳糖5.06%,酪蛋白3.97%,非脂乳固体9.57%,总固形物13.97%;氨基酸总量(TAA)为4.78 g/100 g,其中谷氨酸含量最高,为1.03 g/100 g,甘氨酸含量最低,为0.08 g/100 g,必需氨基酸(EAA)为1.81 g/100 g,非必需氨基酸(NEAA)为2.97 g/100 g,EAA/TAA为37.9%,EAA/NEAA为60.9%;脂肪酸主要以不饱和脂肪酸为主,其中主要是单不饱和脂肪酸,占70.58%;多不饱和脂肪酸主要以γ-亚油酸为主,占1.32%;美仁牦牛乳中共检测出34种挥发性风味物质,包括醛类8种,脂类6种,酮类6种,醇类5种,酸类3种以及其他类6种,主要有2,3-丁二酮、乙酸乙酯、异戊醛、2-庚酮、2-丁酮等挥发性物质。

In order to further develop and utilize Meiren yak milk products,the milk samples of 10 Meiren yaks were collected in May 2022.The milk composition analyzer,automatic amino acid analyzer,gas chromatograph and flavor analyzer were used to detect the contents of conventional nutrients,amino acids,fatty acids and volatile flavor substances.The results showed that the main nutritional components of Meiren yak milk were 6.43%fat,5.45%protein,5.06%lactose,3.97%casein,9.57%non-fat milk solids and 13.97%total solids.The total amino acid(TAA)was 4.78 g/100 g,among which the content of glutamic acid was the highest(1.03 g/100 g),the content of glycine was the lowest(0.08 g/100 g),the essential amino acid(EAA)was 1.81 g/100 g,the non-essential amino acid(NEAA)was 2.97 g/100 g,the EAA/TAA was 37.9%,and the EAA/NEAA was 60.9%.Fatty acids were mainly unsaturated fatty acids,of which monounsaturated fatty acids account for 70.58%.Polyunsaturated fatty acids were mainly linoleic acid,accounting for 1.32%.A total of 34 volatile flavor compounds were detected in Meiren yak milk,including 8 aldehydes,6 lipids,6 ketones,5 alcohols,3 acids and 6 others,there were mainly 2,3-butanedione,ethyl acetate,isopentanal,2-heptanone,2-butanone and other volatile substances.