Studies on the occurrence and formation of 1,2-dicarbonyls in honey

The 1,2-dicarbonyl compounds 3-deoxyglucosulose (3-DG), methylglyoxal (MGO) and glyoxal (GO) were measured for the first time in 21 honey samples as the corresponding quinoxalines after derivatization with orthophenylenediamine using RP-HPLC and UV-detection. Compared to 5-hydroxymethylfural (HMF), which was also quantified, and ranged between 0.6 and 44 mg/kg, up to 100-fold higher amounts of 3-DG were found, ranging from 79 to 1,266 mg/kg. During storage of honey at 35 °C and 45 °C, a linear increase of 3-DG was observed. Values for GO and MGO were in the ranges 0.2-2.7 mg/kg and 0.4-5.4 mg/kg respectively, and were not affected by storage. Using semi-preparative RP-HPLC, glucosone, a 1,2-dicarbonyl compound previously unknown to occur in foods was isolated from a honey sample and characterized by LC-MS and NMR spectroscopy.[PUBLICATION ABSTRACT]