Formation of N^ε-(Carboxymethyl)lysine and N^ε-(Carboxyethyl)lysine in Baked Goods and Advances in Their Inhibition by Plant Polyphenols

Baked goods are among the most widely consumed food products worldwide. During thermal processing, the Maillard reaction occurs, resulting in the formation of advanced glycation end products, particularly N^ε-(Carboxymethyl)lysine and N^ε-(Carboxyethyl)lysine. Increasing evidence has indicated that dietary CML and CEL can accumulate in human tissues and may contribute to the development of chronic diseases, including Diabetes Mellitus and Alzheimer's disease. Therefore, effective control of their formation in baked foods is of great importance for improving food safety and nutritional quality. Currently, various strategies have been proposed to inhibit the formation of CML and CEL, including optimization of raw material composition, regulation of thermal processing conditions, and the addition of exogenous inhibitors. Among these approaches, plant polyphenols have attracted increasing attention due to their natural origin and multifunctional properties, such as antioxidant activity and carbonyl-trapping capacity. In this review, the formation mechanisms, occurrence levels, and influencing factors of CML and CEL in baked foods are systematically summarized. Particular emphasis is placed on the inhibitory effects of plant polyphenols. The potential inhibition mechanisms are further discussed, including antioxidant activity, trapping of α-dicarbonyl intermediates, direct scavenging of CML, and interactions with Maillard reaction substrates. It aims to provide theoretical guidance for the development of healthier baked foods through the application of plant polyphenols.