Development of shelf life kinetic model for fresh rainbow trout (Oncorhynchus mykiss) fillets stored under modified atmosphere packaging

The sensory, chemical (based on the thiobarbituric acid, total volatile basic nitrogen and trimethylamine), and microbial quality (based on the total viable count and lactic acid bacteria count) of the rainbow trout stored under modified atmosphere packaging (MAP) conditions was evaluated. Four different gas combinations, including P1 (80% CO2, 10% N2, 10% O2), P2 (60% CO2, 20% N2, 20% O2), P3 (60% CO2, 40% N2, 0% O2), and P4 (40% CO2, 30% N2, 30% O2), were used. Also, the fish packages were stored at four constant temperatures (including 0, 5, 10, and 15 °C) for 12 days. The absence of oxygen in P3 and high concentration of carbon dioxide in P1 extended the shelf life by delaying the chemical, microbial, and sensory spoilage. Over the storage time of trout fillets in MAP, the rate of chemical reactions significantly increased while the sensory scores decreased. Based on the Arrhenius kinetic modeling for the spoilage reactions of the sensory (total acceptance) and chemical (total volatile basic nitrogen) indices, the shelf life was extended for P3 and succeedingly, for P1 packaging.