INFLUENCE OF SODIUM-CHLORIDE ON ANTIOXIDANT ENZYME-ACTIVITY AND LIPIDOXIDATION IN FROZEN GROUND PORK

Ground pork containing 0-2.0% NaCl was stored at -15 degrees C for 10 weeks. During storage both thiobarbituric acid reactive substances (TB ARS) and lipid peroxides increased with increasing NaCl concentrations . The activity of catalase (CAT), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) decreased 8, 32 and 27%, respectively, afte r 10 weeks of storage. CAT and SOD activity decreased primarily during the first week while GSH-Px activity decreased for up to 4 weeks. To determine if NaCl influenced enzyme inactivation rates, the activity o f the antioxidant enzymes from stored, salted (0.5-2.0%) ground pork w ere determined at equal ionic strengths. Under these conditions, NaCl was not observed to accelerate CAT, SOD and GSH-Px inactivation in gro und muscle during storage. However, altering ionic strength (0.5-2.0% NaCl) in the enzymes assays decreased the activity of muscle-extracted CAT, SOD and GSH-Px suggesting that NaCl could alter the activity of these enzymes in salted pork. The ability of NaCl to reduce the activi ty of the antioxidant enzymes could be partially responsible for the l ower oxidative stability of salted muscle foods. (C) 1997 Elsevier Sci ence Ltd.