Antibacterial activity of agar-gelatin Nano-composite film in combination with peppermint essential oil (Mentha piperita) and its effect on the shelf life of rainbow trout (Oncorhynchus mykiss)

The present study was conducted to evaluate the effect of agar-gelatin Nano-composite film with peppermint essential oil (Mentha piperita) on the quality of rainbow trout fillets (Oncorhynchus mykiss .(The samples were divided into 5 groups of agar-gelatin Nano-composite film (treatment 1), agar-gelatin Nano-composite film with 0.5% essential oil (treatment 2), film with 1% essential oil (treatment 3), film with 1.5% essential oil (treatment 4) and film with 2% essential oil (treatment 5). Samples were stored in the refrigerator for 15 days and at certain intervals (days 0, 3, 6, 9, 12 and 15) for microbiological, chemical (pH, TBA, PV, TVB-N) and sensory tests were evaluated. Essential oil analysis showed that menthol with 49.7% of the main composition of peppermint essential oil. Bacterial results showed that treatments 1 and 2 did not significantly reduce the number of bacteria in comparison with 3, 4 and 5 treatments (p<0.05). The pH of the rainbow trout fillets was not significantly affected by essential oil (p>0.05).TVB-N, TBA and FFA showed the least amount of this indicator in both treatments 1 and 2. However, regarding the total peroxide value and total microbial load, adding essential oil to the film caused a significant reduction in this index with non-essential oil. In all parameters, the lowest level was observed in the treatment with the highest level of essential oil. Significant difference was not significant between the 5 treatments. Based on TVB-N and TVC indexes, treatments 1 (agar-gelatin Nano-composite film) and treatment 2 (agar-gelatinNano-composite film) containing 0.5% peppermint essential oil were treated to 6thday and 3, 4 and 5 (Agar-glatin Nano-composite film) containing 1, 1.5 and 2% peppermint essential oil were allowed to use until the 9th day. According to the present study, agar-gelatin film Nano-composite alone did not have the ability to increase the shelf-life of rainbow trout, but the addition of peppermint essential oil (at levels 1, 1.5 and 2%) was able to increase the duration shelf life was effective for 3 days.