Investigations on the shelf life of rainbow trout fillets covered by quinoa biofilms enriched with different essential oils ( Nigella sativa and Mentha piperita )

Having no adverse effects on the consumer's health, causing zero or minimal damage to the environment, and maintaining the nutritional quality of the product are too important criteria for food packaging materials. Edible biofilm packaging techniques are successful to meet many of these features. To strengthen this claim, rainbow trout (Oncorhynchus mykiss) fillets were coated with an edible film solution (obtained from quinoa starch), which attracted a lot of attention in terms of nutritional value. The prepared biofilm solutions were applied in four different groups (control, quinoa, quinoa + black seed oil, and quinoa + mint oil) and stored in refrigerator conditions (4 ± 1 °C) for 15 days. Microbiological (total aerobic mesophilic bacteria, psychrophilic bacteria, Pseudomonas, lactic acid bacteria, and Enterobacteriaceae) and chemical analyses (TBARS, TVB-N, pH) were performed on certain days of storage. At the end of the study, it was stated that coating fish fillets with edible quinoa, which was enriched by black cumin and mint essential oils, had positive chemical and microbiological results. The highest value for pH was 7.03 ± 0.09 obtained in the control group. It was found that black seed oil has antimicrobial specifications via slowing the microorganism development and prolongs the storage time. The TVB-N value was below the consumable limit value (25 mg/100 g) in the treatment groups and the TBARS value was lowest (1.62 ± 0.21 μmolMA/kg) in the black seed oil group. Consequently, it is suggested that black seed oil may be used on trout fillets to prolong storage time.