THE EFFECT OF METAL CHELATORS, HYDROXYL RADICAL SCAVENGERS, AND ENZYME-SYSTEMS ON THE LIPID-PEROXIDATION OF RAW TURKEY MEAT

The effect of iron chelators, free radical scavengers, and enzyme systems on the formation of hydroxyl radicals and the lipid peroxidation of raw turkey meat was determined. Fresh hand-deboned turkey breast and leg meat without skin or mechanically deboned turkey meat (MDTM) was homogenized with 3 vol of .1 M citrate-phosphate buffer, pH 5.5, or distilled water. Samples were prepared by adding iron chelators, free radical scavengers, or enzyme (xanthine oxidase and superoxide dismutase) systems into the meat homogenate. Free ionic iron was the critical component in the formation of 2-thiobarbituric acid reactive substances (TBARS), and chelation with strong or weak iron chelators was effective in preventing the formation of TBARS in meat, except with weak iron chelators in breast meat. Hydroxyl radical scavengers mannitol, glucose, formic acid, and dimethyl sulfoxide were not effective, but free radical terminators, ascorbate and butylated hydroxyanisol, were very effective antioxidants. Tyrosine had stronger antioxidant effects than hydroxyl radical scavengers. Superoxide dismutase (SOD) and SOD plus catalase had a weak antioxidant effect on lipid oxidation of raw turkey meat but xanthine oxidase had a strong antioxidant effect that could not be explained. The formation of TBARS in meat was mainly catalyzed by the ferryl or perferryl complex-dependent free radicals, not by the superoxide-dependent hydroxyl radicals.