Combined impacts of zein coating enriched with methanolic and ethanolic extracts of sour orange peel and vacuum packing on the shelf life of refrigerated rainbow trout

Abstract

AbstractIn this study, the antioxidant potency of aqueous ethanolic and methanolic extracts of sour orange peel was assessed. The antioxidant and antibacterial characteristics of zein coating enriched with these extracts were then evaluated for refrigerated fish stored with vacuum packing (VP). The antioxidant activities of the hydroalcoholic extract were more potent than those of the methanolic extract. The total viable counts of Enterobacteriaceae, Pseudomonas spp., and psychrotrophic bacteria in all of the samples were significantly decreased, compared with the control, for the storage period. Thiobarbituric acid reactive substances, peroxide, total volatile basic nitrogen, and free fatty acids were significantly lower in all treated samples, compared with the control. In the sensorial assessment, the coated samples enriched with different concentrations of extracts were mostly preferred by the sensory analyst. In combination, the coating layers increased the shelf life of fish for 12 days. Edible coatings are significant protective agents for perishable foods such as seafood. Longer shelf lives are feasible with different processing methods, such as edible coatings and plant extracts, and with suitable combinations of these agents. The enrichment of zein coatings by essential oils or extracts can improve the sensory attributes (such as flavour, taste, and colour), as well as antioxidant and antimicrobial characteristics.