传统风干牦牛肉加工过程中肌原纤维蛋白氧化对氨基酸的影响

Effects of myofibrillar protein oxidation on amino acids during the processing of traditional air-dried yak meat

以甘肃省甘南州公牦牛半膜肌为研究对象,通过对自然风干40 d过程中肌原纤维蛋白中羰基、巯基、二酪氨酸含量,以及过氧化值(peroxide ralue,POV)和硫代巴比妥酸值(thiobarbituric acid value,TBA)的测定来评价蛋白氧化和脂肪氧化程度,并且通过分析氨基酸的变化规律探讨传统风干牦牛肉在加工过程中肌原纤维蛋白氧化对氨基酸的影响。结果表明,随着风干时间的延长,风干肉羰基含量显著增加,巯基含量显著降低,二酪氨酸含量逐渐升高;POV值和TBA值均呈逐渐升高的趋势;同时酪氨酸、亮氨酸及苯丙氨酸对氧化作用非常敏感,氧化前后其含量变化显著(P<0.05)。综合分析,由相关性分析看出蛋白氧化是由脂肪氧化引起,氧化会在一定程度上破坏肉制品的营养特性和风味,该文结果明确了风干时间对牦牛肉品质的影响,为牧区牦牛肉制品的加工及加工方式提供了理论依据。

With semi-membrane muscles of male yak in Gannan Prefecture of Gansu province as the research object,the carbonyl,sulfhydryl and dityrosine contents of myofibrillar protein were determined to evaluate the degree of protein oxidation,and the degree of fat oxidation was investigated based on peroxide value(POV)and thiobarbituric acid value(TBA)during the process of natural freezing-air-drying for 40 days.Subsequently,by analyzing the changes of amino acids,the effect of myofibrillar protein oxidation on amino acids was discussed.The results showed that with the prolongation of processing time,the carbonyl content of myofibrillar protein in yak increased significantly,while the content of sulfhydryl group decreased significantly.The content of dityrosine gradually increased,and the POV as well as TBA both exhibited an upward trend.In addition,the contents of tyrosine,leucine,and phenylalanine changed significantly before and after oxidation(P<0.05),indicating high sensitivity to oxidation.Correlation analysis showed that protein oxidation was caused by fat oxidation,which could damage the nutritional properties and flavor of meat products to some extent.Therefore,the clarification of effect of air drying time on the quality of yak meat provides a theoretical basis for processing and processing methods of yak beef products in Tibetan region.