This study investigated the relationship between postmortem proteolysis, muscle pH decline, sarcomere length (SL), intramuscular fat (IMF) and Warner-Bratzler shear force (WBSF) in four bovine muscles (biceps femoris (BF), infraspinatus (IS), longissimus lumborum (LL), psoas major (PM). The WBSF was low in BF, IS and PM, while LL had a higher value (P < 0.001), but still considered as tender. The PM had fastest pH decline (P < 0.001), ultimate pH was lowest in LL and PM and highest for IS (P < 0.001), sarcomeres were longest for PM and shortest for BF and LL (P < 0.001), while IS and PM had more IMF than BF and LL (P = 0.038). Troponin T degradation was similar in all muscles after 2d postmortem, however after 13d LL had more degradation than IS (P = 0.003). The MMP-2 activity increased during storage (P = 0.001), while IS had less activity than the other muscles (P = 0.022). Although the variation in proteolytic activity could not explain the variation in WBSF, the study provides useful knowledge for the meat industry for optimising processing and storage procedures for different beef muscles.

本研究调查死后蛋白水解，肌肉pH值下降，肌节长度（SL），肌内脂肪（IMF）和华纳-BRATZLER剪切四个牛肌肉（力（WBSF）之间的关系股二头肌（BF），冈（IS），最长lumborum（LL），腰大肌（下午）。WBSF的BF，IS和PM低，而LL的值较高（P <0.001），但仍被认为是嫩的。PM的pH下降最快（P <0.001），LL和PM的终极pH最低，IS的终极pH最高（P <0.001），PM的肉瘤最长，BF和LL的肉瘤最短（P <0.001），而IS和PM的IMF高于BF和LL（P = 0.038）。死后第2天，所有肌肉中的肌钙蛋白T降解相似，但在第13天后LL的降解比IS多（P = 0.003）。在储存过程中，MMP-2活性增加（P = 0.001），而IS的活性低于其他肌肉（P = 0.022）。尽管蛋白水解活性的变化不能解释WBSF的变化，但该研究为优化不同牛肉肌肉的加工和贮藏程序提供了有用的知识，为肉类工业提供了有用的知识。