Influence of bleeding on myoglobin and meat quality changes of Channel catfish muscle during freeze-thaw cycles

The present study investigated the effects of bleeding treatment on myoglobin, color, lipid, and myofibrillar oxidation of Channel catfish fillets during seven freeze-thaw cycles. The oxidation degrees of myoglobin, lipid, and myofibrillar in the samples without bleeding treatment were greater than those in the samples with bleeding treatment during seven freeze-thaw cycles. The L* value of bleeding-treated samples was higher than that of untreated samples, whereas the a* and b* values were lower than those of untreated samples during seven freeze-thaw cycles. Overall, the oxidation of myoglobin exacerbates the oxidation of myofibrillar protein. Moreover, the interaction between the oxidations of myoglobin and the lipid caused changes in the color of Channel catfish fillets. This study reveals the mechanism underlying the complementary oxidation interaction and provides a basis for explaining quality deterioration in fish meat. Our results can be applied for developing strategies to maintain optimal sensory qualities of freshwater fish meat. Novelty Impact Statement Preconditioned aquatic products such as catfish fillets sold by cold chain transportation have a longer shelf life, richer nutritional value, and fresh taste than freshly slaughtered aquatic products, so they are popular among modern consumers. However, insufficient slaughter and bleeding in the preconditioning of aquatic products will cause blood to accumulate in the fish fillets, which will affect the taste and appearance of the product and its shelf life. Therefore, we fully bled the catfish after slaughter and found that the oxidation of lipid, protein, and myoglobin of catfish was delayed, and the color was brighter than that of the no bleeding catfish group. The bleeding treatment after slaughter can be used as an important part of the pretreatment of preconditioned aquatic products to extend the freshness of the conditioned aquatic products.