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

Li, Hai-Lan; Yu, Ying-Hui; Xiong, Guang-Quan; Liao, Tao; Zu, Xiao-Yan

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 fleshes. RESULTS The AV, PV and TBARS presented dose dependent increase in fish meat for both cobalt-60 (60 Co) and electron beam (EB) irradiation. With a 6 kGy of radiation, all measured indices in 60 Co group were significantly higher than those in EB group (P<0.05 or P<0.01). With a 3 kGy of radiation, the AV, PV and TBARS in 200 Gy/min dose rate group were significantly lower than those in 2 Gy/min and 80 Gy/min groups (P<0.05). After 60 Co irradiation, the AV, PV and TBARS in most of fresh samples were significantly higher than those in freeze-dried samples (P<0.01). And 60 Co radiation decreased the unsaturated fatty acid (UFA) content in fresh samples and increased the UFA content in freeze-dried samples. Our study indicated that 60 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 60 Co irradiation. CONCLUSION Low dose (3 kGy) of EB irradiation, high dose rate (200 Gy/min) of 60 Co irradiation or freeze-drying treatment can alleviate the lipid oxidation of largemouth bass meat. This article is protected by copyright. All rights reserved.