Combining effect of gamma irradiation, Thyme essential oil and vacuum packaging on shelf life of shrimp during refrigerator storage

Preservation of perishable foods is a major challenge in the food industry. In this research, the effect of gamma irradiation, thyme essential oil (EO) and vacuum packaging treatments on fresh shrimp for a period of 15 days at 4°C during storage was investigated. For this purpose, two concentrations of EO (0.4 and 0.8% v/w) and two doses of radiation (2.5 and 3.5 KGy) were used. Treated shrimps and control sample were subjected to chemical (pH, total volatile basic nitrogen, free fatty acids, peroxide index, thiobarbituric acid reactive substances and color indexes), microbiological (bacteria total count, psychrophilic bacteria and Escherichia coli) and sensory evaluation and analyses performed on certain days (0, 5, 10 and 15) of storage. The obtained results showed that pH, FFA, peroxide, TBARS and TVB-N values of all treatments increased in the duration of storage, significantly (p