Effect of irradiation on Nε-carboxymethyl-lysine and Nε-carboxyethyl-lysine formation in cooked meat products during storage

•The effect of irradiation on CML and CEL formation in meat products is investigated.•CML and CEL contents in irradiated meat products exhibit a higher growth rate than non-irradiated samples.•PUFAs oxidation induced by irradiation promotes CML and CEL formation.•Lipid oxidation pathways are an important pathway for CML and CEL accumulation in irradiated samples during storage.

This study investigated the effects of irradiation on Nε-carboxymethyl-lysine (CML) and Nε-carboxyethyl-lysine (CEL) formation in cooked red and white meats during storage. The results showed that irradiation did not affect CML/CEL formation (0 weeks). After 6 weeks, CML/CEL contents in the irradiated samples exhibited a higher growth rate than the non-irradiated samples, especially the red meat. The results of electron spin resonance spectrometry and 2-Thiobarbituric acid-reactive substances suggested irradiation had induced free-radical reactions and accelerated lipid oxidation during storage. A linear correlation (r=0.810–0.906, p<0.01) was found between the loss of polyunsaturated fatty acids content and increase of CML/CEL content in the irradiated samples after 0 and 6 weeks of storage. The results indicate that irradiation-induced lipid oxidation promotes CML/CEL formation, and CML/CEL formation by the lipid oxidation pathways may be an important pathway for CML/CEL accumulation in irradiated meat products during storage.