The influence of bleeding on post-mortem tenderization of fish muscle during storage was studied. Six fish species were used for the present study. Among them, delay of post-mortem tenderization of muscle by bleeding was shown in the pelagic fishes: yellowtail, horse mackerel, and striped jack. On the other hand, bleeding had no influence on the muscle firmness of the bottom fishes: red sea bream, flatfish, and rudder-fish. According to transmission electron microscopy, degradation of pericellular collagen fibrils was delayed in bled yellowtail and horse mackerel. In the case of striped jack, though, collagen fibril degradation could not be observed; slower weakening of the pericellular connective tissue was detected by compression tests on the bled sample. On the contrary, no structural difference was observed between the tested and the control samples in the bottom fishes during storage. According to these results, the delay of muscle tenderization of pelagic fishes would be due to the outflow of a collagenolytic factor contained in blood.
Ando, M.; Nishiyabu, A.; Nakagawa, T.; and Makinodan, Y.
"Influence of Bleeding on Post-Mortem Tenderization of Fish Muscle During Chilled Storage,"
Scanning Microscopy: Vol. 10
, Article 24.
Available at: https://digitalcommons.usu.edu/microscopy/vol10/iss3/24