Effects of dietary enrichment with alpha-tocopherol acetate and post-harvest filleting on lipid oxidation and flesh quality of tropical farmed barramundi (Lates calcarifer)

Abstract

Pre-harvest dietary enrichment with α-tocopherol acetate in combination with different post-harvest processing techniques was investigated with regard to quality degradation of farmed barramundi (Lates calcarifer), during chilled storage. Fish were fed commercial rearing diets supplemented with two levels of α-tocopherol acetate (standard level 192 mg kg− 1 and enriched level 628 mg kg− 1). During 5 months of feeding, α-tocopherol content of fish fed the enriched diet increased significantly from an initial concentration of 13.67 to 24.18 mg kg− 1 after 56 days. After this period fish were harvested and subjected to 14 day chilled (2 °C) storage as either fillets or whole ungutted fish. Dietary α-tocopherol enrichment in combination with storing fish whole and ungutted constrained lipid oxidation over 14 days of storage, in comparison lipid oxidation was significantly higher in fish fed the standard diet and filleted prior to storage. Filleting also resulted in significant colour changes with reddening and yellowing of the flesh in conjunction with significantly lower flesh pH compared to barramundi stored whole and ungutted. These results indicate that dietary enrichment with α-tocopherol acetate in combination with storing fish whole and ungutted is the most effective strategy in constraining lipid oxidation and colour fluctuations in barramundi flesh during chilled storage.