Effects of added salt, phosphates, and proteins on the chemical and physicochemical charactersitics of frozen cod (Gadus morhua) fillets

Cod fillets were injected with brine, then immersed in brine with the same composition as used for injection, and finally frozen in a plate freezer. The composition of the brine varied with groups, containing phosphates (3%), salt (5%), and/or proteins (10%), soy protein concentrate, or hydrolyzed cod proteins. The fillets were stored at -24°C for 3 mo and then thawed to evaluate the effects on yield after thawing and cooking, drip, water-holding capacity, pH, and chemical composition. Addition of proteins slightly increased the yield of thawed fillets, but salt and phosphates were more effective. Comparison of the different proteins showed that fish proteins were not as effective as soy proteins with respect to the physicochemical parameters evaluated with the exception of water-holding capacity. The use of both type of proteins resulted in a negative appearance of the fillets, such as discoloration and slimy surface.