Increasing oxidative stability of precooked trout fillet using herbal essential oils

Abstract

The antioxidant effect of tarragon and summer savory herbal essential oils (EOs) on precooked trout fillets during frozen storage period was investigated in this study. Three groups of fish fillets were treated with tarragon EO and three other groups were treated with summer savory EO and then cooked by different cooking methods (frying, oven baking and steaming). During the storage period, fat hydrolysis was evaluated through measuring free fatty acid value (FFA) and oxidation products were measured via peroxide value (PV) and thiobarbutiric acid reactive substances value (TBARS). During the storage period, the amount of FFA was high in oven baked samples (0.34–0.53% oleic acid) and steamed fillets (0.56–0.84% oleic acid). Following the control, the highest PV was obtained from fried fillets treated with summer savory (4.53–4.67 meq/kg) (P<0.05). Also, TBARS in fried and steamed samples containing summer savory was higher than samples containing tarragon (P<0.05). Overall acceptability score of antioxidant treated samples was higher than that of controls (P<0.05). The results of this study showed that tarragon and summer savory essential oils retarded the oxidation during frozen storage and samples treated with tarragon showed slower hydroperoxide and malonaldehyde formation than those of summer savory-treated or the control samples.