Flesh quality of raw and smoked fillets of Atlantic salmon as influenced by dietary oil sources and frozen storage

Abstract

The aim of this study was to evaluate the effects of dietary oil source and frozen storage on flesh quality characteristics of Atlantic salmon. Four diets containing either 100% of Peruvian fish oil (PO), capelin oil (CO), soybean oil (SO) or low-erucic acid rapeseed oil (RO) as supplemental oil were fed to triplicate groups of salmon for 135 days. After slaughter, half of the fish were smoked while the rest were analysed when raw. For smoked and raw fish, the left fillet was analysed as fresh fillet while the right fillet was frozen and stored at −20 °C for two or four months before analyses. Fish fed SO and PO diets had firmer texture than fish fed RO diet. Liquid holding capacity (LHC) and colour evaluation were influenced by dietary oil source. Colour of fish fed fish oil-diets had significantly higher colour than fish fed vegetable oil-diets. Frozen storage decreased the firmness of raw fillets and the LHC of raw and smoked fillets. Colour evaluation was affected by frozen storage by increasing L *, a * and b * values whereas muscle carotenoid concentrations slightly decreased. Lipid oxidation was more pronounced in fish fed high levels of n-3 fatty acids and increased with frozen storage.