[关键词]
[摘要]
本文研究了不同嫩度羊肉肌浆蛋白磷酸化水平随宰后成熟时间的变化。取40只羊宰后0.5 h、1 h、4 h、12 h、24 h背最长肌样品,根据24 h剪切力和肌原纤维小片化指数分为高嫩度组和低嫩度组。采用SDS-PAGE电泳、荧光染色等方法,分析肌浆蛋白的磷酸化水平。研究结果表明在宰后24 h内肌浆蛋白磷酸化水平在不同嫩度和宰后成熟时间处理组之间差异显著(P<0.05),低嫩度组的整体蛋白质磷酸化水平在宰后4 h达到最大,高嫩度组的整体蛋白质磷酸化水平在宰后12 h达到最大。宰后0.5 h、1 h、4 h低嫩度组的肌浆蛋白整体磷酸化水平显著高于高嫩度组(P<0.05)。因此,肌浆蛋白磷酸化水平受不同嫩度和宰后成熟时间处理影响显著(P<0.05),磷酸化可能通过对宰后肌肉糖酵解的作用影响宰后肌肉僵直进程,进而影响肌肉嫩度。
[Key word]
[Abstract]
The major aim of this study was to investigate the changes in the levels of phosphorylation of sarcoplasmic proteins with respect to the postmortem ageing time in mutton with different levels of tenderness. Longissimus muscle samples of 40 sheep were collected at 0.5, 1, 4, 12, and 24 h postmortem, and were divided into two groups (high-level-of-tenderness and low-level-of-tenderness) based on the shear force and myofibrillar fragmentation index (MFI) at 24 h postmortem. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was combined with fluorescence staining in order to analyze the level of phosphorylation of sarcoplasmic proteins. The results of these analyses indicated that groups with different degrees of tenderness and postmortem times showed significantly different levels of sarcoplasmic protein phosphorylation within 24 h (postmortem). The highest levels of protein phosphorylation in the low-level-of-tenderness and high-level-of-tenderness groups were observed at 4 and 12 h postmortem, respectively. In addition, the global levels of sarcoplasmic protein phosphorylation observed in the low-level-of-tenderness group at 0.5, 1, and 4 h postmortem were significantly higher than those observed in the high-level-of-tenderness group. Therefore, the level of sarcoplasmic protein phosphorylation was significantly affected by the varying degrees of tenderness and the different postmortem times (P < 0.05); moreover, it was theorized that protein phosphorylation influences rigor mortis in postmortem muscles through glycolysis, thereby affecting muscle tenderness.
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[基金项目]
公益性行业(农业)科研专项(201303083);国家农业科技创新工程