ON THE ROLE OF ,3-DIHYDRO-3,5-DIHYDROXY-6-METHYL-4(H)-PYRAN-4-ONE IN THE MAILLARD REACTION

To investigate the thermal degradation pathways of ,3-dihydro-3,5-dihy droxy-6-methyl-4(H)-pyran-4-one (1) in the Maillard reaction, the C-13 -labeled and unlabeled 1 were synthesized and heated in model systems of food processing. The extent and position of the labeling of the rea ction products were interpreted by the mass spectroscopy data. The vol atiles identified were, among others, 2,4-dihydroxy-2,5-dimethyl-3(2H) -furanone (2), 2,5-dimethyl-4-hydroxy-3(2H)-n-furanone, cyclotene, mal tol, 5-hydroxymaltol, and some acyclic carbonyls. Under roasting condi tions, 2 was formed as a major product. It was concluded that 1 might be transferred to highly reactive open-chain intermediates like the en olic forms of 1-deoxyosone. The further reaction pathways varied with the reaction conditions. Possible degradation pathways of 1 that resul ted from the labeling experiments as well as the formation of the desc ribed products are discussed.