High pressure processing (HPP) of pre-rigor longissimus thoracis (strip loin) from prime and bull animals substantially decreased the shear force and improved consumer eating attributes of the final meat product. The improved tenderness in both prime and bull meat was associated with a lower myofibrillar fragmentation index and reduced calpain 1 activity which indicated the mechanism of tenderisation was different from that which occurred in chill aged meat. Light microscopy showed disruption to the fibre packing within the muscle and electron microscopy confirmed significant disruption of the Z discs and M lines and disappearance of the A lines. Thus, HPP is associated with a reduction in the structural integrity and strength of the sarcomeres. These effects were consistent in strip loins sourced from prime and bull stock. HPP also led to the movement of glycogen phosphorylase from the sarcoplasmic fraction to the insoluble myofibrillar fraction in all animals and this was associated with a higher pH at 24 h.

严格的长经胸廓高压处理（HPP）原始动物和公牛的（腰部里脊）大大降低了最终肉制品的剪切力并改善了消费者的进食特性。初级和公牛肉中嫩度的改善与肌原纤维碎裂指数降低和钙蛋白酶1活性降低有关，这表明嫩化的机理不同于冷鲜肉中的嫩化机理。光学显微镜显示破坏了肌肉内的纤维堆积，电子显微镜确认了Z盘和M线的显着破坏和A线的消失。因此，HPP与肉瘤的结构完整性和强度降低有关。这些效果在来自原始和牛市的带状里脊上是一致的。