Kinetic study on the generation of furosine and pyrraline in a Maillard reaction model system of d-glucose and l-lysine

•A Maillard reaction (MR) model system of d-glucose and l-lysine was investigated.•Generation mechanisms of furosine and pyrraline were revealed in the MR model system.•Furosine is preferred to undergo the reaction between methylglyoxal and l-lysine.•Pyrraline is preferentially started from 3-deoxyglucosone through Pyrrole reaction. A kinetic model for Maillard reaction (MR) model system of d-glucose and l-lysine was established; activation energy (Ea) of each step was calculated. Potential generation pathways of furosine and pyrraline were a combination of either 3-deoxyglucosone (3-DG) or methylglyoxal (MG) with l-lysine. Ea value for furosine generated through 3-DG pathway was 81.70 ± 14.01 kJ mol−1, which was significantly higher than that through MG pathway (52.08 ± 4.48 kJ mol−1). As for pyrraline, Ea for the 3-DG pathway (53.45 ± 4.02 kJ mol−1) was significantly lower than that through the MG pathway (110.22 ± 18.77 kJ mol−1). Results of the kinetic study indicated that furosine was preferred to be generated through the MG pathway since MG is more likely to react with each other and form a furan ring as a precursor of furosine. Pyrraline was more easily to be generated from the 3-DG pathway through cyclization of 1,4-dicarbonyl compounds to pyrrole.