Abstract:The frozen Longissimus dorsi (LD) of yak meat were taken as the experimental objects to investigate the effects of different thawing methods on the protein oxidation, functional properties and freshness of yak meat. The results showed that the myofibrillar protein carbonyl groups were the highest of 9.80nmol/mg, surface hydrophobicity was the highest of 48.53μg and the total sulfhydryl groups were the lowest of 41.73nmol/mg and Ca2+-ATPase activity was the lowest of 0.245U/mg protein in the air thawing yak meat, which was significantly different from other thawing methods (p<0.05), indicating that the meat protein oxidation was the heaviest after air thawing. And the other thawing methods resulting in protein oxidation in descending order were refrigerated thawing, hydrostatic thawing, microwave thawing, and room temperature thawing. The protein solubility was 109.28mg/g, MP solubility was 69.16mg/g and EAI was 31.51m2/g in the air thawing yak meat, all of which were significantly lower than those of other thawing methods (p<0.05), indicating that air thawing was most unfavorable to meat proteolysis and emulsification. Meanwhile, the lipid peroxidation of refrigerated thawed yak meat was the lowest as well as the TVB-N of microwave thawed yak meat was the lowest. There was a significant correlation between protein oxidation and lipid oxidation in thawed yak meat, and also between protein solubility and emulsifying ability (p<0.01). These above results indicated that the air thawing was most detrimental to the quality of thawed yak meat, followed by thawing at room temperature. However, refrigerated thawing, microwave thawing and hydrostatic thawing respectively can delay the onset of meat quality decline process effectively in different levels, and can maintain the defrosted meat quality to some extent. The findings can provide data support and theory reference for illustrating the mechanism of different thawing methods on defrosted meat quality in the future.