Mechanisms of lipid peroxidation in meats from different animal species

The objectives of this study were (1) to determine the elements that make differences in the oxidative stability of meats from different animal species and (2) to determine the major catalysts of lipid peroxidation in meat and meat products. The most important difference in the susceptibility of meat from different animal species to lipid peroxidation was the balance between anti- and pro-oxidative factors in meat. Raw and cooked ground beef were the most susceptible to lipid peroxidation, followed by chicken thigh meat, pork, and chicken breast meat. The high storage stability of chicken breast meat was attributed to a very low concentration of myoglobin and high total antioxidant capacity (TAC), which prevented the release of free ionic iron from myoglobin and inhibited free radical chain reactions. The high susceptibility of beef to lipid peroxidation was due to the imbalance of pro- and anti-oxidant factors caused by relatively low TAC and high amount of myoglobin, which served as a major source of catalysts such as ferrylmyoglobin, hematin, and/or free ionic iron. The level of lipid peroxidation catalyzed by diethylenetriamine pentaacetic acid (DTPA)-chelatable iron released from myoglobin in the water-soluble high molecular weight (HMW) fraction from beef significantly decreased with the addition of water-soluble low molecular weight (LMW) and water-insoluble (P) fractions, indicating that most of the free ionic iron released from myoglobin were chelated by LMW and P fractions. Therefore, it is suggested that ferrylmyoglobin and/or hematin, rather than free ionic iron, are the major catalysts of lipid peroxidation in raw beef during "normal" storage conditions. Beef showed a significantly higher level of "stable" ferric iron reducing capacity (FRC) than did chicken breast under conditions that can induce the generation of sufficient amounts of free ionic iron, indicating that reduced iron also played an important role in lipid peroxidation of beef.