Effects of oleic acid on the formation and kinetics of Nε-(carboxymethyl) lysine

The contents of glucose, N-epsilon-(carboxymethyl)lysine (CML), and two main intermediate products, glyoxal (GO) and fructoselysine (FL), were determined, and the corresponding mathematical models were established to investigate the formation and kinetics of CML in a glucose-lysine model heated at 80 degrees C for 50 h. The effects of oleic acid (OA), temperature, and energy on CML formation were considered in the kinetic models. The mathematical modeling results suggested that glucose consumption was incomplete at 50 h and 80 degrees C. Although OA contributed to the formation of GO, CML was primarily formed from FL via the Maillard reaction, not from GO. The Arrhenius model was used to deduce that FL is the main pathway in the glucose-lysine-OA system because 88.39 kJ/mol of activation energy via the GO pathway was significantly higher than the 73.97 kJ/mol of activation energy via the FL pathway, and because the rate constant k(4) was higher than k(3) at different temperatures. OA (50 mmol/L) acted as a catalyst as well as a reactant in CML formation. This is the first study in which CML formation has been determined by both multi-response modeling and kinetic models based on glycation and lipid oxidation.