Effects of chitosan edible coatings enriched with sumac on the quality and the shelf life of rainbow trout (Oncorhynchus mykiss Walbaum 1792) fillets

Abstract

Effects of chitosan coating combined with sumac on the quality of rainbow trout (Oncorhynchus mykiss) fillets stored in refrigerated condition (4°C) for 12 days were evaluated. The treatments in this study were—T1 control, T2 chitosan: 2% w/v, T3 chitosan: 2% w/v and sumac: 1% w/v, and T4 chitosan: 2% w/v and sumac: 2% w/v. The shelf life of the samples were determined periodically using physicochemical (pH peroxide value [PV] thiobarbituric acid [TBA] and total volatile basic nitrogen [TVB-N]) microbiological (total viable counts [TVCs] and psychrotrophic bacteria) and sensory analyzes. During the storage period T3 and T4 groups showed lower pH PV TBA and TVB-N values than T1 and T2 groups. The sensory results are in line with chemical and microbiological results. Treatment with 2% chitosan + 1% sumac and 2% chitosan + 2% sumac increased the shelf life of rainbow trout fillets by 6 days as compared to the control samples. Practical applications: To avoid the adverse effects of chemical preservatives and to answer natural and reliable product demands of the consumers plant extracts and edible coatings are applied to increase the shelf life and to prevent the spoilage of fresh fish. The results of this study reported the efficacy of chitosan edible coating combined with sumac as a new natural preservative for improving the shelf life of rainbow trout fillets. The findings revealed that sumac extract combined with chitosan coating can be an alternative method to extend the shelf life to preserve the quality and safety of fish as a result of their good antioxidant and antimicrobial activity. © 2019 Elsevier B.V. All rights reserved.