新疆山羊肉的食用品质及差异蛋白质分析

Analysis of edible quality and protein of Xinjiang goat

宰后成熟的过程中,肌肉中蛋白质的表达水平和参与的代谢调节不同,均对肉品质的调节起关键作用。为了深入探索宰后成熟过程中的差异蛋白对新疆山羊肉品质的影响,明确肉质较好的最适成熟时间,该研究测定了宰后不同时间下的新疆山羊背部最长肌的pH值,并采用串联质量标签技术比较死后不同成熟时期的蛋白质水平变化。共得到级质谱谱图总数518230个,匹配到的谱图总数量为47666张,唯一肽段总数14466个,蛋白质总数2526个。大多数差异表达在山羊宰后成熟中下调表达,其中只有2个糖酵解相关差异蛋白(PGM1,LDHB)上调表达;且与能量代谢相关的线粒体核糖体蛋白L46(MRPL46)、线粒体核糖体蛋白S15(MRPS15)、39S核糖体蛋白L41(MRPL41)、线粒体核糖体蛋白L22(MRPL22)等差异蛋白显著上调表达。结果表明,山羊肌肉的糖代谢过程能维持到肉质成熟的48 h以后,促进肉色的稳定和肉质的嫩化,而线粒体作为能量代谢的关键部位调节肉质嫩度的变化。在成熟期间的肉质逐渐嫩化,且24 h时嫩化程度最高,进一步表明宰后成熟起到嫩度优化的作用。

In the process of post-mortem maturation,the proteins’expression level and metabolism regulation of muscle are different,which plays a key role in the regulation of meat quality.In order to further explore the effect of maturation after slaughter on the quality of Xinjiang goat meat,the optimal maturation time for meat quality was determined.In this study,the longissimus dorsi muscle of Xinjiang goats was used as the experimental sample to determine the pH value at different postmortem times,and the proteome changes at different postmortem maturation stages were compared by using TMT proteomics technique.A total of 518230 grade mass spectra were obtained.The total number of matched spectra was 47666,including 14466 unique peptides and 2526 proteins.Most of the different expressions were down-regulated in postmortem maturation of goats,and only two glycolysis related differential proteins(PGM1,LDHB)were up-regulated.Mitochondrial ribosomal protein L46(MRPL46),Mitochondrial ribosomal protein S15(MRPS15),39S ribosomal protein L41(MRPL41),mitochondrial ribosomal protein L22(MRPL22)and other differential proteins related to energy metabolism were significantly up-regulated.The results showed that the process of sugar metabolism of goat meat was maintained for 48 hours,which promoted the stability of meat color and the tenderness of meat quality.Mitochondria as a key part of energy metabolism regulated the change of meat tenderness.During the maturation of the meat,the meat was tender gradually,and the tenderness degree was the highest at 24 h,which further indicated that the postmortem maturation played the role of tenderness optimization.