Effect of chitosan-gelatin film incorporated with ethanolic red grape seed extract and Ziziphora clinopodioides essential oil on survival of Listeria monocytogenes and chemical, microbial and sensory properties of minced trout fillet

The aim of the present study was to evaluate the effects of chitosan-gelatin film incorporated with grape seed extract (GSE) (1 and 2%) and Ziziphora clinopodioides essential oil (ZEO) (1 and 2%), separately and in combination, on survival of Listeria monocytogenes and shelf life extension of minced trout fillet during refrigerated storage (4 +/- 1 degrees C) over a period of 11 days. The control and wrapped fillet samples were analyzed for chemical (PV and TVB-N), microbial (Total mesophilic and psychrotrophic bacteria, Pseudomonas spp., P. fluorescens, Shewanella putrefaciens, lactic acid bacteria and Enterobacteriaceae family) and sensory properties (odor, color and acceptability). The GC-MS analysis of the essential oil components revealed that carvacrol (65.22%) and thymol (19.51%) were the most representative components of the essential oil. In comparison with control group, fish spoilage was significantly delayed in samples wrapped in chitosan-gelatin film containing different concentrations of GSE and/or ZEO (P < 0.05). The lowest bacterial growth, PV and TVB-N content were obtained in fish samples wrapped in film containing ZE02%+GSE2%. The fillets treated with ZEO2%+GSE1% and ZEO2%+GSE2% had the best organoleptic properties. Based on our findings, the antibacterial activity of chitosan-gelatin film incorporated with GSE and ZEO enhanced the shelf life of fish fillet. (C) 2016 Elsevier Ltd. All rights reserved.