Seasonal change in collagen content of red seabream muscle

Abstract

To investigate the correlation between firmness and the collagen content in fish muscle, we evaluated the seasonal change in collagen content of red seabream muscle on the basis of the content of protein-form hydroxyproline. Since a significant difference was observed among the ratios of proline (Pro) hydroxylation in female fish (P<0.05), the collagen content of each sample tested was converted from the ratio of Pro hydroxylation. The collagen content in male fish tended to increase from 0.96 mg/g muscle (March) to 1.27 mg/g (June), and then to decrease to 0.81 mg/g (July). In both male and female fish, the collagen contents tended to increase from July to September. Linear regression analysis revealed that there was a positive correlation between the muscle firmness and the collagen content in each month (P<0.05, male; r=0.686, female; r=0.742). The results suggest that the seasonal change in collagen content in muscle possibly contributes to that in firmness.