Effects of gamma irradiation on sensory, chemical and microbiological quality of frog legs (Rana esculenta) during cold storage (2°C)

The effects of gamma irradiation (0, 4 and 5 kGy) on the chemical, microbiological and sensorial quality of frog legs (Rana esculenta) during cold storage (2°C) were investigated. The major fatty acids of frog legs in all groups were found as palmitic acid, stearic acid, oleic acid, linoleic acid ve cis-11,14,17-eicosatrienoic acid. The fatty acids indicated before were not affected by the irradiation process. While TVB-N values of control groups found as 50.11 mg/100 g after a 10 day storage period, 4 and 5 kGy samples were found as 48.08 and 43.29 mg/100 g respectively after 17 days. However, it was observed that TBA values for irradiated frog legs were higher than for unirradiated samples at the end of their storage periods. It was found that Salmonella was totally eliminated by irradiation at a dose of 4 kGy. Other microbiological analysis (TVC, PB, Enterobactericeae) showed that an irradiation at 5 kGy were the best at eliminating bacteria even if a dose of 4 kGy was also eliminated bacteria significantly. On the bases of sensorial evaluation, the shelf life of frog legs during cold storage was 10 days for unirradiated frog legs and 17 days for the irradiated ones. There were no significant differences on shelf life between irradiation at doses of 4 and 5 kGy. It was also observed that sensory assessment results have supported by the chemical and microbiological analyses.