Effects of injection of protein solutions prepared from fish by-products on yield and chemical properties of chilled and frozen saithe (Pollachius virens) Fillets

Fish gelatine and protein solutions prepared from saithe by-products were injected into saithe fillets. Effects on weight changes, water holding capacity, and chemical composition of the fillets were investigated after chilled (2, 5, and 7 days) and frozen (14 and 49 days) storage. The results showed that higher weight yields were obtained by adding proteins and salt to the fillets in comparison with only salt, especially in chilled fillets. The drawback of the injection was that higher drip losses were found during storage and thawing than for untreated fillets. Effects of injection on water content were only significant after 2 days of chilled storage, but differences leveled out after longer storage time and with freezing and thawing of the fillets. The procedure applied in this study seems to be promising for utilization of by-products such as trimmings as an ingredient in higher value products like fillets, in comparison to mince products.