The temporal increase (P < 0.05) of MGO in Fru-Gly, Fru-Lys and Glu-Gly model systems under prolonged heating is shown in Fig. 4. MGO concentration in the Glu-Lys MR mixtures reached a maximum value of 80.3 μg/g d.m. after heating for 60 min, a distinct difference to the 90.0 μg/g d.m. reached within only 5 min in the Rib-Lys model. There was a relatively greater amount of MGO generated in the Fru-Gly and Fru-Lys MR mixtures compared to both Glu-Gly and Glu-Lys models, respectively when the reaction time is less than 60 min.