Formation of α-dicarbonyl fragments from mono- and disaccharides under caramelization and Maillard reaction conditions

Glyoxal, methylglyoxal and diacetyl were identified as reaction products from non-enzymatic browning of D-glucose (Glc), D-fructose (Fru), maltose and maltulose. The α-dicarbonyl compounds were quantified throughout the reaction. Monosaccharides formed more dicarbonyl fragments than disaccharides and Glc formed more than Fru. It is suggested that Fru tends to yield cyclic products rather than fragmentation products under the reaction conditions used. Furthermore, a mechanism for the fragmentation of disaccharides is proposed.