Thermal processing of food results in the formation of α-dicarbonyl compounds (α-DCs) such as glyoxal (GO), methylglyoxal (MGO), 2,3-butanedione (2,3-BD) and 3-deoxyglucosone (3-DG), which are precursors of potentially harmful advanced glycation end products. Some of the α-DCs found in food products might result from chemical deterioration reactions during storage and reheating. A range of sugary food simulation systems were stored at three different temperatures (4 °C, 25 °C and 37 °C) and reheated using three different processing methods to investigate the formation and migration of α-DCs.During 20 days of storage, the concentration of α-DCs declined, following which the concentration remained approximately constant. MGO was the major α-DCs affected during storage, its relative content being decreased from 233.71 μg/mL to 44.12 μg/mL in the glucose-lysine system. The concentration of α-DCs decreased with increasing temperature. Microwave reheating increased the formation of α-DCs compounds. The largest increases in 3-DG concentrations were observed in the maltose-lysine systems (24.94 to 35.74 μg/mL). The concentration of α-DCs had small difference in response to reheating at 100 °C, but declined when reheated at 150 °C.The concentration of α-DCs following storage and reheating depends on the type of sugar, lysine content, temperature, and method of reheating. This article is protected by copyright. All rights reserved.