Gamma-irradiation induced effects on biogenic amine formation and quality of frog legs (Rana esculenta) during storage

Chemical, microbiological and sensorial properties were investigated depending on the storage time to understand the impacts of gamma irradiation at doses of 4 and 5 kGy on frog legs (Rana esculenta) during storage at 2 °C. While TVB-N values of control groups found as 50.11 mg/100 g after a 10 day storage period, 4 and 5 kGy frog legs were found as 48.08 and 43.29 mg/100 g respectively after 17 days. TBA values for irradiated frog legs were observed to be higher at the end of their storage periods. Salmonella was totally eliminated by 4 kGy irradiation. A total of seven biogenic amines; putrescine, cadaverine, spermidine, spermine, histamine, serotonin and agmatine were recorded in frog legs. Ammonia, putrescine, cadaverine and agmatine contents of non-irradiated group were significantly increase during storage period. Other microbiological analysis showed that irradiation at 5 kGy was the best at eliminating bacteria. Consequently, the treatment of irradiation as a preservation method was found to prolong the shelf life of frog legs 7 days longer than the usual methods in cold storage.