Post-mortem softening of fish muscle during chilled storage as affected bybleeding

Bleeding caused the delay of muscle softening in yellowtail, horse mackerel , and striped jack, which are pelagic fish. Conversely, bleeding had no inf luence on the muscle firmness of red sea bream, flatfish, and rudder-fish, which are demersal fish. Transmission electron microscopy showed delay of d egradation of pericellular collagen fibrils in bled yellowtail and horse ma ckerel. Striped jack showed slower weakening of the pericellular connective tissue in a compression test. However, the demersal fish had no structural difference due to bleeding. These results indicate that removal of blood c ould delay collagen fibril degradation and muscle softening of pelagic fish .