Effects of water holding capacity of snakehead induced by protein oxidation during frozen storage

Snakehead is a kind of fish and its nutritional and economic value is very high, but it is easy to deterioration and lead to the quality problem during the storage.The water retention-related indicators of snakehead fillets were studied after the fillets were oxidized by oxidation system and frozen at-4 ℃, this experiment studied the changes of snakehead muscle water holding capacity.The results showed that there were obvious changes after frozen storage at-4 ℃, thawing loss rate, p H, pressing loss rate, cooking loss rate of oxidized snakehead fillets ( group A) were higher than those of unoxidized snakehead fillets ( group B) .On the 10 th day, the thawing loss rate, pressing loss rate, cooking loss rate of group A was 7.51%, 14.74% and 10.65% higher than that of group B, respectively. Protein carbonyl content, Thiobarbituric acid value ( TBARS) and myofibril fragmentation index ( MFI) increased significantly, demonstrating the water holding capacity dropped. In the correlation analysis, the carbonyl content, TBARS and MFI of oxidized samples with myofibrillar protein structural were significantly correlated with thawing loss rate, pressing loss rate and cooking loss rate, respectively ( p < 0.01) , and MFI were correlated with p H ( p < 0.05) .These results showed that the hydroxyl radical oxidation system coulddamage the structure of myofibrillar proteins and make the proteins oxidative degradation in snakehead, leading to a decline in its water holding capacity.