ALTERATION OF POSTMORTEM AGING IN BEEF BY THE ADDITION OF ENZYME-INHIBITORS AND ACTIVATORS

Twenty-four hours after stunning, slices of beef M. semitendinosus were soaked in buffers at 10 degrees C at different pH values containing enzyme inhibitors or calcium and magnesium salts and their enzyme levels and toughness determined up to 9 days. High pH meat was tender but appeared to have the same rate of ageing as meat of normal pH. Calcium chloride accelerated ageing and produced, after completion of conditioning, more tender meat than controls. In tenderising, sodium and potassium chlorides were 43% and MgCl2 73% as effective as Ca salts. Cysteine proteinase inhibitors were more effective in preventing ageing than serine or aspartate inhibitors. Cysteine and aspartate inhibitors together were the most effective in preventing ageing. The inhibition of ageing by cysteine inhibitors was overcome in the presence of 30 mM CaCl2. The results suggest a main, but not exclusive, role for calpains in meat ageing and showed a synergistic non-enzymic tenderisation by the addition of high concentrations of salts.