To investigate the antioxidant capacity of calcium lactate on m-calpain activity, porcine m-calpain was preincubated with various combinations of hydrogen peroxide (H2O2), calcium chloride (CaCl2), and/or different concentrations of calcium lactate (CaLac). The m-calpain was activated by CaLac, and the extent of m-calpain oxidation by H2O2 was decreased with increasing CaLac concentrations. These results suggest that CaLac addition to early postmortem muscle may lead a significant improvement of meat tenderness by providing an activation of endogenous calpain enzymes and protection against protein oxidation.