高铁肌红蛋白氧化对牦牛肉肌原纤维蛋白生化特性的影响

为探究高铁肌红蛋白(metmyoglobin,MetMb)氧化处理对宰后牦牛肉成熟24 h肌原纤维蛋白生化特性的影响,以不同浓度(0、0.01、0.05、0.5 mmol/L)MetMb氧化体系氧化孵育24 h的牦牛肉肌原纤维蛋白为研究对象,以未加氧化剂的肌原纤维蛋白为空白对照,测定不同氧化浓度下肌原纤维蛋白的羰基浓度、巯基浓度、二硫键浓度、表面疏水性、Ca/K-ATPase活性、二聚酪氨酸等指标的变化规律。结果表明,随着MetMb浓度的增加,不同处理组间牦牛肉肌原纤维蛋白均表现出不同程度的氧化水平,其中羰基浓度、二硫键浓度、表面疏水性、二聚酪氨酸含量和Ca-ATPase活性均呈显著增加趋势(P<0.05),巯基浓度和K-ATPase活性则显著降低(P<0.05)。当氧化液浓度增加至0.5 mmol/L时,羰基浓度较空白对照组升高了近4倍,而巯基浓度较空白对照组下降31.5%。综上,MetMb氧化促使肌原纤维蛋白发生了不同程度的氧化,增加了蛋白的氧化程度。本研究结果为牦牛肉生产加工过程中蛋白氧化控制提供了一定的参考。

Effect of Metmyoglobin Oxidation on Biochemical Characteristics of Myofibrillar Protein in Yak Meat

In this study,we investigated the effect of metmyoglobin(MetMb)oxidation on the biochemical characteristics of yak muscle myofibrillar proteins at 24 h postmortem.The pattern of change in the contents of carbonyl,sulfhydryl and disulfide bonds,surface hydrophobicity,Ca/K-ATPase activity and dimeric tyrosine in myofibrillar proteins was determined after 24 h of oxidative incubation of MetMb at different concentrations(0,0.01,0.05 and 0.5 mmol/L).A sample without any added oxidant was served as a control.The results showed that with the increase in MetMb concentration,the oxidation level of myofibrillar proteins varied.The contents of carbonyl,disulfide bond and dimeric tyrosine,surface hydrophobicity,and Ca-ATPase activity significantly increased(P<0.05),whilst the opposite was true for sulfhydryl content and K-ATPase activity(P<0.05).When MetMb concentration increased to 0.5 mmol/L,the carbonyl content increased by 5 flod,while the sulfhydryl content decreased by 31.5%as compared with the blank treatment group.In summary,the oxidation of MetMb promotes the oxidation of myofibrillar proteins.The results of this study provide a reference for protein oxidation control during the production and processing of yak meat.