Browning Potential of C₆-α-Dicarbonyl Compounds under Maillard Conditions

In this work, the three major C₆-α-dicarbonyl compounds glucosone (GLUC), 1-deoxyglucosone (1-DG), and 3-deoxyglucosone (3-DG) were synthesized and examined under Maillard conditions (aqueous solutions with the addition of l-alanine at 130 °C and pH 5/8). For the first time, the resulting color formation, antioxidant activity, and generation of short-chained α-dicarbonyls were investigated and compared to incubations of d-glucose and d-fructose. An additive effect on the formation of color, an antagonistic effect on the generation of α-dicarbonyl compounds, and a synergistic effect on the antioxidant activity could be observed for the 1-DG/GLUC combination. Despite their common degradation products, different extinctions could be measured, with 3-DG showing the strongest color formation, followed by GLUC and 1-DG. The analyzed α-dicarbonyl compounds have no direct impact on the formation of color but are precursors for most of the colored compounds. The main difference between the three substances is their ability to form different heterocyclic degradation products, such as pyranones (1-DG), furanones (1-DG), furans (GLUC and 3-DG), and the corresponding N-heterocycles in the presence of amino components. This seems to be the main reason for their varying browning potential and antioxidant activity.