Cobalt-60 and electron beam irradiation-induced lipid oxidation in largemouth bass (Micropterus salmoides).

Background: Irradiation can cause lipid oxidation of fish. This study aimed to examine the effect of radiation (method, dose and dose rate) on the acid value (AV), peroxide value (PV), thiobarbituric acid reactive substances (TBARS) content and fatty acid profile of fresh and freeze-dried largemouth bass flesh.

Results: AV, PV and TBARS presented a dose-dependent increase in fish meat for both cobalt-60 ( Co) and electron beam (EB) irradiation. With a 6 kGy dose of radiation, all measured indices in the Co group were significantly higher than those in the EB group (P < 0.05 or P < 0.01). With a 3 kGy dose of radiation, AV, PV and TBARS in the 200 Gy min dose rate group were significantly lower than those in the 2 and 80 Gy min groups (P < 0.05). After Co irradiation, AV, PV and TBARS in most fresh samples were significantly higher than those in freeze-dried samples (P < 0.01). And Co irradiation decreased the unsaturated fatty acid (UFA) content in fresh samples and increased the UFA content in freeze-dried samples. Our study indicated that Co irradiation, particularly at a low dose rate, accelerated lipid oxidation in fish meat. A large amount of muscle moisture enhances the amount of UFA loss in fish meat during Co irradiation.

Conclusions: A low dose (3 kGy) of EB irradiation, a high dose rate (200 Gy min ) of Co irradiation or freeze-drying treatment can alleviate the lipid oxidation of largemouth bass meat. © 2020 Society of Chemical Industry.