Effects of temperature during frozen storage on lipid deterioration of saithe (Pollachius virens) and hoki (Macruronus novaezelandiae) muscles

•Lipid deterioration of two lean fish species during frozen storage was evaluated.•Lipid composition and degradation were evaluated on both light and dark muscles.•Lower storage temperature (−30°C) showed significantly more preservative effects.•Marked difference observed in the composition of dark muscle of the two species.•Tertiary lipid oxidation and hydrolysis products are strongly correlated to sensory. Lipid deterioration of two lean fish species, saithe (Pollachius virens) and hoki (Macruronus novaezelandiae), during frozen storage at −20 and −30°C (up to 18months) was studied. Lipid composition, lipid oxidation and hydrolysis, and sensory attributes were evaluated on both light and dark muscles of the fish species. Results showed significant lipid deterioration with extended storage time, but lower storage temperature showed significantly more preservative effects. A marked difference was observed between the composition of dark muscle of hoki and saithe. Polyunsaturated fatty acids were the predominant lipids in dark muscle of saithe, while monounsaturated fatty acids were predominant in dark muscle of hoki. Further, the hydrolytic activity differed greatly between dark muscle of hoki and saithe, with significantly lower activity observed in hoki. Present results indicate that both tertiary lipid oxidation and hydrolysis products are appropriate for assessing lipid deterioration of saithe and hoki light muscle during frozen storage.