New insights into the tenderization pattern of yak meat by ROS-ERS: Promotion of ERS-associated apoptosis through feedback regulation of PERK/IRE1/ATF6 and caspase-12 activity.

This study aimed to investigate the molecular mechanisms of reactive oxygen species (ROS)-induced endoplasmic reticulum stress (ERS) in apoptosis and meat tenderization during postmortem aging. Yak longissimus dorsi muscle was incubated with N-acetylcysteine (NAC), 4-phenylbutyric acid (4-PBA) and NAC + 4-PBA, respectively, and stored at 4 °C for 0 h, 12 h, 24 h, 72 h, 120 h and 168 h. The results showed that NAC and 4-PBA treatments significantly reduced ROS content and endoplasmic reticulum stress levels. Meanwhile, the specific inhibitory effect of 4-PBA affected Ca content, caspase-12 activity, endoplasmic reticulum apoptotic cascade reaction and meat tenderization by preventing myogenic fiber degradation. Additionally, the combined treatment of NAC + 4-PBA had a more significant effect than the other groups, confirming the necessity of targeted regulation of the ROS-ERS axis. Overall, our findings provide new insights into the critical role of ROS-mediated ERS in caspase-12-dependent apoptosis and yak meat tenderization during yak meat postmortem.