Effect of gamma irradiation on physico-mechanical and structural properties of basil seed mucilage-chitosan films containing Ziziphora clinopodioides essential oil and MgO nanoparticles for rainbow trout packaging

摘要

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 mucilagechitosan- 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).