Effect of active composite coating enriched with Echinacea purpurea L. Moench extract on the shelf life of Oncorhynchuus mykiss fillet during cold storage

To investigate the effect of active composite coating carboxymethyl cellulose-based on the shelf life of rainbow trout (Oncorhynchuus mykiss) fillet during refrigerator temperature storage, an experiment for 12 days with 5 treatments including uncoated (control), carboxymethyl cellulose 1%, carboxymethyl cellulose-oleic acid 1%, carboxymethyl cellulose-oleic acid-Echinacea extract (0.5% or 1%) and 3 replications was carried out. Chemical (PV, TBARS, and TVN) and microbial (TVC and PTC) tests were performed on the fillets every 3 days. The results showed that oleic acid improved the protective effect of carboxymethyl cellulose coating. The antioxidant and antibacterial effect of Echinacea extract was concentration dependent. At the end of the storage period, the lowest values of PV (3.90±0.11 meq/kg), TBARS (1.24±0.27 mg MDA/kg), TVN (21.90±1.83 mg/100g), TVC (5.10±0.10 log cfu/g) and PTC (5.23±0.06 log cfu/g) were found in fillets containing active composite coating of carboxymethyl cellulose-oleic acid-1% Echinacea extract (P <0.05). Therefore, the composite coating of carboxymethyl cellulose-oleic acid-1% Echinacea extract can be used as an active packaging to maintain the quality and increase the shelf life of rainbow trout fillets during short-term storage at refrigerator temperature.