Please use this identifier to cite or link to this item: http://hdl.handle.net/1946/4131
The main objective of the project was to study the influence of added ingredients, mainly functional fish proteins, on chemical and physicochemical properties of chilled and frozen whitefish fillets. Fresh saithe and cod fillets and light salted cod fillets were injected with fish protein solutions and compared with salt injected (1.5% and 4%) and untreated control fillets. The fillets were stored at +2°C and -24°C for various times. Evaluations were made on the effects on yield, water holding capacity, chemical composition and T2 transversal relaxation time. Additions of fish proteins increased the weight gain considerably after injection of the fillets, compared with salt injected fillets, but varied with types of fish protein solutions. Adding fish protein solutions into cod fillets before chilled or frozen storage increased the storage yield and reduced drip loss of the fillets, compared with control and salt injected fillets. Addition of fish protein hydrolysate (FPH) and homogenized fish proteins (HFP) were particularly effective. These protein solutions showed also considerable improvement with regard to the total yield of the cod fillets. Addition of fish proteins and/or salt into fillets showed less effect on the water holding capacity of the muscle than expected. The most promising fish protein solutions to increase water holding capacity was the FPH solution. In summary, injection of protein solutions into cod and saithe fillets is an effective means to improve or stabilize the weight and WHC of the fillets, but more optimisation is needed with regards to different raw materials. The cod fillets showed better results than the saithe fillets. The saithe fillets seem to be more sensitive for this kind of treatment (injection and freezing) than cod fillets, but gaping is well known problem for saithe fillets. Addition of fish protein solutions into fish fillets is an option that is worth to take a look at.