Improvement of lipid stability of refrigerated rainbow trout (Oncorhynchus mykiss) fillets by pre-storage α-tocopherol acetate dipping treatment

One of the simplest methods for short-term handling and storage of fish is the refrigeration in combination with dip treatments. This study was conducted to determine the effect of pre-storage α-tocopherol acetate dipping treatments on lipid stability of refrigerated rainbow trout fillets. Trout fillets were dipped in α-tocopherol acetate solutions (200 and 500 mg kg-1 flesh) and subsequently stored in a refrigerator at 4 ˚C for 12 days. Control samples received no α-tocopherol acetate during dip treatment. At the end of 0، 3، 6، 9 and 12 days of storage، lipid damage analysis of trout fillets was performed. A continuous notable increase (p < 0. 05) in peroxide value (PV)، thiobarbituric acid (TBA) and free fatty acid (FFA) was observed for all samples throughout the storage period. Although throughout the storage period the lipid hydrolysis (FFA) of fish fillets was not affected by α-tocopherol acetate solutions، successful (p < 0. 05) inhibition of lipid oxidation (PV and TBA) in refrigerated trout fillets was possible with dip treatment in α-tocopherol acetate solutions (200 and 500 mg kg-1 flesh). There was no significant (p > 0. 05) effect of increasing α-tocopherol acetate concentration on the lipid deterioration of fish fillets. These results indicated that α-tocopherol acetate especially at lower level (200 mg kg-1 flesh) was very effective in retarding the lipid oxidation