Effect of Iron-Catalyzed and Metmyoglobin Oxidizing Systems on Amino Acid Changes of Yak Myofibrillar Protein

In this study, the changes in amino acid content of yak meat myofibrillar protein under specific oxidative intensity metabolism were compared and analyzed in yak meat maturation and in the iron-catalyzed oxidizing system (IOS) and the metmyoglobin oxidizing system (MOS). The results showed that the contents of threonine, cysteine, glycine, alanine, leucine and lysine decreased significantly with aging time (P < 0.05). The contents of threonine, cysteine and arginine were significantly reduced with increasing oxidation intensity in both oxidizing systems (P < 0.05). In addition, the contents of methionine and tyrosine decreased significantly in IOS (P < 0.05), while the contents of glycine, leucine and lysine decreased significantly in MOS (P < 0.05). The results showed that different oxidizing systems were specific to the oxidation of amino acids of myofibrillar protein in yak meat. According to the change of amino acid composition and content, greater oxidative damage occurred in MOS compared with IOS.