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.