Iced storage of Atlantic salmon (Salmo salar) – effects on endogenous enzymes and their impact on muscle proteins and texture

Endogenous salmon enzymes and their impact on muscle proteins and texture were studied. To reduce interfering effects of microbial enzymes, the fish were irradiated. Irradiation of salmon fillets resulted in severe inhibition of cathepsin B-like and collagenase-like enzymes. The effect was most pronounced for the cathepsins. The textural properties and amounts of free amino acids and extractable proteins in the irradiated fillets and control group were different after 14 days of iced storage. Even with the increased load of microorganisms seen in the control group, no severe deterioration of fish texture or increase in proteolytic activity was observed during the storage period. It therefore seems that microorganisms are not important for changes in salmon texture.