Abstract:The effects of different thermal reaction conditions （temperature， pH， reaction duration， and substrate molar ratio） on the simultaneous generation pattern of 3 dicarbonyl key intermediates in a glucose-free ammonia Maillard reaction system were studied. The samples were pretreated by o-phenylenediamine pre-column derivatization， and the content of glyoxal （GO）， methylglyoxal （MGO）， and 3-deoxyglucosone （3-DG）in the system was determined by high performance liquid chromatography （HPLC）. The results showed that temperature greatly influenced the amount of MGO generated， and the generation rate of MGO was significantly increased when the heating temperature exceeded 120 ℃， resulting in a decrease in the content of GO and 3-DG in the system. The generation of 3-DG was greatly affected by pH， with the maximum amount at pH6，whereas the amount of GO and 3-DG increased with the increase in pH in the range of pH 5-9. As the reaction duration extended， the 3 intermediates were gradually accumulated. The accumulation rate of MGO was significantly higher than that of GO and 3-DG， and the content of MGO reached the maximum value firstly at the time point of 90 min. The elevation in the proportion of reducing sugar in the substrate led to a significant increase in the generation of MGO and 3-DG in the system， while it had no significant effect on the generation of GO. During the heating processing of food， the processing conditions can be controlled to reduce the generation of dicarbonyl intermediates and decrease the content of hazardous substances therein.