Oxidative stability of Atlantic salmon (Salmo salar, L.) fillet enriched in α-, γ-, and δ-tocopherol through dietary supplementation

The purpose of this study was to examine the effect of dietary tocopherols on the oxidative stability of Atlantic salmon fillet. The fish were fed four diets supplemented with 150mg kg−1 α-tocopherol and different combinations of γ- and δ-tocopherol (50 or 100mgkg−1) for 10 months, slaughtered, and stored for 16 days on ice, or 48 weeks at −30 °C. Fillet concentrations of tocopherols at slaughter were 0.101 ± 0.001, 0.091 ± 0.004 and 0.025 ± 0.002 times feed concentration for α-, γ- and δ-tocopherol, respectively. Fillet α-tocopherol, but not γ- and δ-tocopherol, was moderately lowered during iced and frozen storage. The non-α-tocopherols protected the fillet against lipid oxidation in a dose-dependent manner during frozen storage, but appeared to act as prooxidants during storage on ice. It is concluded that α-tocopherol may be better suited than mixed tocopherols as a tool to optimize the oxidative stability of Atlantic salmon fillet.