The objective of this study was to determine the proteolytic changes of myofibrillar and small heat shock proteins (HSPs) in different muscles during aging and to evaluate their relevance to meat quality attributes. From 8 beef carcasses, longissimus lumborum (LL), semimembranosus (SM), and psoas major (PM) muscles were obtained, cut into sections and assigned to various aging periods up to 23d. PM exhibited limited aging potential in quality developments shown by lower extents of shear force, water-holding capacity (WHC), and proteolytic changes, including calpain 1 autolysis, troponin T, and HSP27 compared to LL and SM. Conversely, LL had an increase in tenderization and WHC, which was accompanied with more extended calpain 1 autolysis, proteolysis and HSP27 degradation, compared with other muscles. The results of this study suggest that postmortem proteolytic changes of myofibrillar proteins, small HSPs and apoptotic factors occur in a muscle-specific manner, which is likely attributed to different rate and extent of meat quality developments of each muscle during aging.

这项研究的目的是确定衰老过程中不同肌肉的肌原纤维和小的热休克蛋白（HSP）的蛋白水解变化，并评估它们与肉品质属性的相关性。从8个牛肉car体中提取腰肉（LL），半膜（SM）和腰大肌获得（PM）肌肉，将其切成薄片，并分配到长达23天的各种衰老期。PM与LL和SM相比，在质量发展中表现出有限的老化潜力，这表现为较低的剪切力，保水能力（WHC）和蛋白水解变化，包括钙蛋白酶1自溶，肌钙蛋白T和HSP27。相反，与其他肌肉相比，LL的嫩化和WHC升高，钙蛋白酶1的自溶，蛋白水解和HSP27降解更加延长。这项研究的结果表明，肌原纤维蛋白，小的热休克蛋白和凋亡因子的死后蛋白水解改变是以肌肉特有的方式发生的，这很可能是由于衰老过程中每条肌肉的肉质发展的速率和程度不同所致。