Effect of thyme essential oil and packaging treatments on chemical and microbiological properties of fresh rainbow trout (Oncorhynchus mykiss) fillets during storage at refrigerator temperatures

Abstract

In this research, the effect of thyme essential oil (EO) and packaging treatments (vacuum and modified atmosphere) on fresh rainbow trout fillets during storage for a period of 18 days at 4°C was investigated. Fillets were subjected to microbiological (total viable count(TVC), Pseudomonas, lactic acid bacteria, Enterobacteriaceae) and chemical [pH,thiobarbituric acid reactive substances (TBARS), total volatile basic nitrogen (TVB-N)] analyses on certain days (0, 3, 6, 9, 12, 15, 18th) of storage. TBARS and TVB-N values ​​increased in the duration of storage. Bacterial growth was inhibited in samples with increased concentration of thyme oil due to the antimicrobial activity of thyme oil. Overall, the combined use of thyme EO (0.8%, v/w) and modified atmosphere packaging (MAP) showed a synergistic effect for shelf-life extension of rainbow trout fillets. Key words: Modified atmosphere packaging (MAP), rainbow trout, shelf life, thyme essential oil, vacuum.