Recent Advances in the Analysis of Coloured Maillard Reaction Products

Summary The objective of the work was to separate and identify low molecular weight heterocyclic reaction products from xylose-glycine and glucose-glycine model systems refluxed for 2 h with the pH maintained at 5. Diodearray spectra and HPLC retention times were obtained for the resolved peaks of these model systems and for a series of standard compounds. Two peaks (one of which was coloured) were isolated from the xylose system and five peaks (two of which were coloured) were isolated from the glucose system. They were subjected to 1H- and 13C-NMR and mass spectral analyses. The colourless peaks were identified as the known structures 4-hydroxy-5-methyl-3(2H)-furanone (from xylose), 4-hydroxy-2-(hydroxymethyl)-5-methyl-3(2H)-furanone (from glucose), 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (from glucose) and 5-hydroxymethylfurfural (from glucose). The coloured compounds were the novel structure, 2-acetyl-5-hydroxymethyl-4,5-dihydropyridin-4-one (from xylose) and two isomers of a related acetyldi(hydroxy-methyl)dihydropyridinone (from glucose).