细胞凋亡对牦牛肉成熟过程中品质的影响

The Research of Apoptotic in Yak Muscles during Postmortem Aging

摘要:

为研究宰后牦牛肉在成熟过程中前驱肱三头肌（TB）、中部背最长肌（ML）、后驱半膜肌（SM）中细胞凋亡过程对其品质变化的影响，选取24头甘南黑牦牛按照伊斯兰方式进行屠宰，于0~4 ℃、风速0.5 m/s条件下成熟，在成熟过程中不同时间点（1、3、5、7 d）进行剪切力、MFI、肉色、蒸煮损失、细胞凋亡率以及caspase-3活力测定。TB、ML和SM在宰后1~5 d剪切力值显著降低（p<0.05），MFI显著上升（p<0.01）；L*、a*、b*值在宰后3 d显著升高（p<0.01）；蒸煮损失在宰后1~7 d呈先上升后下降的趋势；宰后5-7d TB、SM的细胞凋亡率在是一个极显著增加的过程（p<0.01），宰后7 d，TB和ML中阳性细胞核数量差异极显著（p<0.01）；TB、ML和SM在宰后0.5 h检测到caspase-3活力，宰后12 h ML的caspase-3达到最高活力。相关性分析中宰后牦牛肉中凋亡率的变化、caspase-3活力的变化与成熟过程中嫩度、肉色和持水力的变化是显著相关的。结果说明，牦牛肉宰后成熟过程中细胞凋亡的发生，及其程度的加深与牦牛肉品质变化是同步进行的。

Abstract:

Twenty-four Gannan yak were slaughtered according to Islamic way of slaughtering, then aged at 0~4 ℃ with wind speed of 0.5 m/s . The shear force, MFI, color, apoptotic rate and caspase-3 activity during postmortem aging were determined. The shear force value in triceps brachi (TB), musculus longissimus (ML) and semimembranosus (SM) after slaughtered of 1~5 d was significantly lower (p <0.05), and MFI significantly increased (p <0.01); L *, a *, b * values were significantly higher at the 3rd d of postmortem aging, a *, b * values decreased significantly at 5~7th d of postmortem aging (p <0.01); the cooking loss first increased and then decreased at 1~7th d of postmortem aging; the apoptosis rate in TB and SM had very significant increase in process (p <0.01), the positive nuclei number in TB and ML had difference during postmortem aging (p <0.01); it was detected caspase-3 activity in TB, ML and SM at 0.5 h postmortem, while it was reached the highest in ML at 12 h postmortem. Across correlation analysis, the yak skeletal muscle cell apoptosis and its degree of deepening were related to the changes of tenderness, meat color (L *, a *, b *) and water holding capacity, as well as the yak meat quality change.