Effect of gamma irradiation on physico‐mechanical and structural properties of basil seed mucilage‐chitosan films containingZiziphora clinopodioidesessential oil and MgO nanoparticles for rainbow trout packaging

Abstract

In the present study, it was aimed to evaluate the effect of gamma irradiation (0, 2.5, and 5 kGy) on physico-mechanical and structural properties of basil seed mucilage-chitosan-based films containing Ziziphora clinopodioides essential oil (ZEO: 0%, 1%, and 2%) and magnesium oxide nanoparticles (MgO: 0%, 0.1%, and 0.2%), and their application on trout fillet´s shelf-life during refrigerated storage for 18 days. The irradiated films under the cobalt-60 source at 5 kGy dose had better tensile strength as well as lower swelling index and water vapor transmission rate compared with other prepared films. Therefore, all films selected to package trout fillets were irradiated at 5 kGy dose. Fillets packaged with films containing ZEO 2% + MgO 0.2% and ZEO 2% + MgO 0.1% had the lowest microbial population (total viable count, psychrotrophic count, Pseudomonas spp., P. fluorescens, H2S producing bacteria, and Enterobacteriaceae) and chemical changes (total volatile base nitrogen content and peroxide value) (p < .05). Practical applications Active packaging has been introduced to increase the shelf-life of fresh fishery products during refrigerated storage. Gamma irradiation is a nonthermal method of food preservation and has recently received great interest in betterment of the physico-mechanical properties of packaging biopolymers. Our findings indicated that irradiation at 2.5 and 5 kGy doses can be used as a tool for improvement of the property of basil seed mucilage-chitosan-based films. The designated films containing Ziziphora clinopodioides essential oil (1% and 2%) and MgO nanoparticles (0.1% and 0.2%) could improve the shelf-life of trout fillets up to 18 days during refrigerated storage condition.