Title: Effects of salt and protein injection on yield and quality changes during storage of chilled and frozen saithe fillets

Protein solutions prepared from saithe cut offs was used to inject saithe fillets. Weight gain, drip loss, fillet yield, cooking yield, colour, WHC, sensory evaluation, chemical and microbiological properties of chilled and frozen saithe fillets were investigated after chilled ( 2 and7 days) and frozen conditions ( 14 and 49 days). The results showed that injection of protein isolate resulted in higher drip loss but also higher fillet yield compared with the control. No difference was found in lightness (L value) and whiteness among the groups except that whiteness of frozen fillets injected with frozen isolate after 49 days was lower than that of the control. Frozen protein isolate injections resulted in a higher water holding capacity (WHC) but fresh protein injections in the lowest WHC of the frozen fillets. No difference was observed in sensory attributes, TVC, H2S, TVB-N, TMA and pH between the groups during chilled and frozen storage. Protein isolates showed positive effects on the sensory attributes such as texture attributes like tenderness and juiciness, and also on odour attributes like meat and vanilla. Based on these results, injection of protein isolate into saithe fillets is considered as an effective means to improve or stabilize the yield and the quality of saithe fillets.