2‑Deoxyglucosone: A New C6‑α-Dicarbonyl Compound in the Maillard Reaction of d‑Fructose with γ‑Aminobutyric Acid

In this study, α-dicarbonyl compounds consisting of a backbone with six carbon atoms resulting from the Maillard reaction of d-fructose with γ-aminobutyric acid were determined. The reaction was carried out under mild reaction conditions at 50 °C and water contents between 0 and 90%. A thus far unknown α-dicarbonyl compound was found as the main product in the first 24 h at water contents below 50%. After isolation of its stable quinoxaline derivative, it was possible to identify the compound as 2-deoxy-d-glycero-hexo-3,4-diulose (2-deoxyglucosone). For the first time, the four C6-α-dicarbonyl compounds, 1-deoxyglucosone, 2-deoxyglucosone, 3-deoxyglucosone, and 4-deoxyglucosone, could be identified in the Maillard reaction of a hexose at the same time. This indicates the formation of a 2,3-eneaminol from the Schiff base of d-fructose and the formation of 2-amino-2-deoxy-3-ketose as an alternative to the Heyns product.