Chitosan nano-coating incorporated with green cumin (Cuminum cyminum) extracts: an active packaging for rainbow trout (Oncorhynchus mykiss) preservation

This study surveyed the effect of chitosan nano-coating (CNC) with green cumin extract (GCE) on the shelf life and quality of rainbow trout fillet (RTF) vacuum packaging during storage at 4 °C. The chemical composition of GCE was determined using GC–MS. The total phenolic content of GCE was 108.65 ± 2.76 mg GAE/g dry sample. GCE demonstrated a potent ability to inhibit DPPH and OH free radicals. The effects of GCE on chitosan coatings were also investigated during storage and on the quality of Oncorhynchus mykiss at 4 °C. The number of aerobic mesophilic bacteria, coliforms, and lactic acid bacteria significantly increased with raising the storage time at 4 °C; this increase was less at higher concentrations of GCE (p < 0.05). The rise in moisture, fat, and ash content of fish fillets was consistent with the rising trend of GCE concentration in the treatments, such that CNC with 2% GCE (T4) was the best treatment. The treatments revealed an inverse trend in the amount of salt and protein, and thus the highest level of parameters was observed in the controls. An increasing trend was observed in PV, TBA, and TVB-N index in the treatments during the storage, but this rising trend decreased with raising the GCE concentration. Finally, T4 with 36.12 ± 0.86 wt% and a score of 4.6 compared to other treatments demonstrated better cooking quality and sensory characteristics and was the best treatment. Therefore, GCE can possess natural antimicrobial and antioxidant properties with a chitosan coating to preserve the quality of O. mykiss fillets.