不同预处理牦牛乳在冻藏期间脂肪酸品质变化研究

Changes in Fatty Acid Quality of Yak Milk with Different Pretreatments during Frozen Storage

冷冻贮藏是克服牦牛乳生产的季节性、产量低、泌乳期短等问题的重要手段,本研究的目的是明确经过不同预处理下牦牛乳在冻藏期间脂肪酸的变化规律。采用GC-MS等方法,探讨冷鲜牦牛乳(4℃,预冷4 h)和巴氏杀菌牦牛乳(63℃下杀菌,30 min)贮藏于-18℃保存0 d、3 d、6 d、9 d、12 d、15 d、18 d、21 d脂肪酸的变化。冷鲜和巴氏杀菌牦牛乳中26种饱和脂肪酸含量贮藏期间无显著变化(P>0.05)。牦牛乳中单不饱和脂肪酸以油酸为主,而多不饱和脂肪酸以亚油酸为主,经巴氏杀菌后在贮藏过程中总含量变化均不显著。巴氏杀菌促进了牦牛乳在冷冻贮藏过程中饱和脂肪酸的稳定性,并最大限度保留易被人体吸收的不饱和脂肪酸。巴氏杀菌与冷冻贮藏技术的联用对于提升牦牛乳贮藏品质具有积极作用。本研究结果可为牦牛乳贮藏加工技术的开发提供重要的理论依据。

Frozen storage is an important means to overcome the problems of seasonality,low yield and short lactation period of yak milk production.The aim of this study was to clarify the changes of fatty acids during frozen storage of yak milk after different pretreatments.The changes of fatty acids in cold fresh yak milk(4℃,precooled for 4h)and pasteurized yak milk(sterilized at 63℃,for 30 min)stored at-18℃for 0,3,6,9,12,15,18 and 21 days were investigated by GC-MS.The contents of 26 saturated fatty acids in the cold fresh yak milk and pasteurized yak milk had no significant change during storage(P>0.05).The total content of monounsaturated fatty acids in yak milk,mainly oleic acid,and polyunsaturated fatty acids,mainly linoleic acid,did not change significantly during storage after pasteurization.Pasteurization promoted the stability of saturated fatty acids in yak milk during frozen storage,and retained the unsaturated fatty acids that are easily absorbed by humans.The combination of pasteurization and frozen storage technology played a positive role in improving the storage quality of yak milk.The combination of pasteurization and frozen storage technology had a positive effect on improving the storage quality of yak milk.The results of this study can provide an important theoretical basis for the development of yak milk storage and processing technology.