Evaluation of antibacterial and antioxidant effect of gelatin-chitosan bilayer edible coating containing nanoemulsion of Perovskia abrotanoides Kar. essential oil on growth control of Aeromonas hydrophila inoculated into rainbow trout fillet

In this study, the effect of bilayer edible coating of gelatin-chitosan containing nanoemulsion of Perovskia abrotanoides Kar. essential oil on growth control of Aeromonas hydrophila inoculated into rainbow trout fillets over a 12-day period at 4 °C was investigated. The chemical composition of the essential oil was evaluated by GC-MS, its antibacterial properties by disk diffusion, plate well and micro-dilution broth, and its antioxidant properties by DPPH.Treatments included control, gelatin, chitosan, gelatin+essential oil, chitosan+essential oil and gelatin-chitosan+essential oil. After preparation, the treatments were packed in sterile polyethylene bags in laboratory conditions and stored for 12 days at 4 °C and their microbial, chemical and sensorial properties were evaluated every 3 days. The results of GC-MS showed that eucalyptol (24.51%) and camphor (22.02%) are the main components. The MIC and MBC of Perovskia abrotanoides Kar. essential oil nanoemulsions were reported to be 0.0625 and 0.125%, respectively. The amount of TVB-N and POV increased during the study period. According to the results of POV and pH measurements, there was a significant difference between all treatments and control treatment (P<0.05). The mean reduction log of bacteria was significantly different between all treatments and the highest antibacterial effect was observed in the gelatin-chitosan coating containing nanoemulsion of Perovskia abrotanoides Kar. essential oil. According to the results, Perovskia abrotanoides Kar. essential oil has good antioxidant and antimicrobial properties and according to the test results, it was found that chitosan-gelatin coating containing nanoemulsion of  Perovskia abrotanoides Kar. essential oil has an effective antimicrobial effect against Aeromonas hydrophila and can protect sensory properties and increase shelf life of rainbow trout fillets as well as useful coating to increase the shelf life of food products.