Effect of bleeding treatment and perfusion of yellowtail on lipid oxidation in post-mortem muscle

The present study investigated the effects of bleeding treatment and perfusion of antioxidant compounds on lipid oxidation in ordinary and dark muscles of yellowtail in the early stage of ice storage. The lipid hydroperoxide contents of dark muscles obtained from yellowtails with and without bleeding treatment were higher and increased more rapidly than those of ordinary muscles. There were no significant differences in the rates of change of the lipid hydroperoxide content (up to 48 h), fatty acid composition and metmyoglobin formation between dark muscles with and without bleeding treatment. Physiological saline containing ascorbic acid or 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox^®) was perfused into live yellowtail or added to minced dark muscle. Trolox^® significantly (P < 0.01) delayed the accumulation of lipid hydroperoxide in dark muscle compared to ascorbic acid in perfusion experiment. These results indicate that simply removing a portion of the blood from live yellowtail by bleeding is not sufficient to prevent lipid oxidation in the early stage of ice storage. Contrary to this, addition of antioxidants into fish flesh is effective to delay lipid oxidation in post-mortem muscle.