Effects of calcium and zinc ions injection on caspase‐3 activation and tenderness in post‐mortem beef skeletal muscles

Summary This study was designed to investigate the effects of Ca 2+ and Zn 2+ ions injection on post‐mortem tenderness and caspase activation by examining the expression of caspase‐3 and cytochrome c in post‐mortem beef skeletal muscles treated with Ca 2+ and Zn 2+ . Results showed that Ca 2+ ions injection accelerated post‐mortem tenderisation of beef skeletal muscles, whereas Zn 2+ retarded the process. In the Ca 2+ ‐injected samples, the level of caspase‐3 precursor decreased markedly without the production of activated caspase‐3, whereas the level of cytochrome c was increased markedly. So, Ca 2+ possibly promoted caspases activation upstream of cytochrome c release, but inactivated caspase activity by calpain and/or fast depletion of ATP ; whereas Zn 2+ blocked the activation of procaspase‐3 with no visible change in the level of cytochrome c, and the block possibly resulted from its direct inhibition on caspase‐3 enzyme.