羟自由基氧化对牦牛肉肌原纤维蛋白生化特性的影响

为探究羟自由基(·OH)氧化处理对宰后牦牛肉成熟过程中肌原纤维蛋白氧化特性的影响,以经不同浓度(0、0.5、1、5、10、20 mmol·L^-1)羟自由基氧化体系氧化不同时间(0、0.5、1、12、24、48 h)的牦牛肉为研究对象,以未经处理的牦牛肉为空白对照,测定不同浓度不同氧化时间下肉样肌原纤维蛋白的羰基含量、巯基含量、二硫键含量、表面疏水性、Ca/K-ATPase活性等指标的变化规律。结果表明,随着H₂O₂浓度的增加及氧化时间的延长,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,其中羰基含量、二硫键含量和Ca-ATPase活性均呈显著增加趋势(P<0.01),而表面疏水性呈先上升后下降的趋势,巯基含量和K-ATPase活性则显著降低(P<0.01)。H₂O₂浓度增加至20 mmol·L^-1时,与空白对照组相比,羟自由基处理组羰基含量升高46.03%,而巯基含量下降79.79%。综上,羟自由基促使宰后牦牛肉成熟过程中肌原纤维蛋白发生了显著氧化,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 Hydroxyl Radical Oxidation on the Biochemical Characteristics of Myofibrillar Protein of Yak Meat

To explore the effects of the treatment with the hydroxyl free radical(·OH) on myofibril protein oxidation characteristics during yak meat postmortem. The yak meat oxidized with different concentrations (0, 0.5, 1, 5, 10 and 20 mmol·L^-1) of hydroxyl free radical oxidation system at different times (0, 0.5, 1, 12, 24 and 48 hours) were as the research objects, and untreated yak meat as the control groups. The change rules of myofibril protein carbonyl, thiol and disulfide bond content, surface hydrophobicity, Ca/K- ATPase activity was measured. The results showed that yak meat myofibrin presented different degrees of oxidation levels among different treatment groups with the increase of H₂O₂ concentration and the extension of oxidation time. Furthermore, the content of carbonyl group, disulfide bond and Ca- ATPase activity all presented a significant increase trend (P<0.01), the surface hydrophobicity increased at first but then decreased, and the content of sulfhydryl group and K-ATPase activity decreased significantly (P<0.01). When H₂O₂ concentration was increased to 20 mmol·L^-1, the carbonyl content of the hydroxyl radical treatment group was 46.03%, higher than that of the blank control group, while the sulfhydryl group content was 79.79% lower. In summary, hydroxyl radicals promoted significant oxidation of myofibrillar proteins during the maturation of post-mortem yak meat, increasing the degree of oxidation of the protein. The results of this study provide a reference for protein oxidation control during the production and processing of yak meat.