D-tagatose is a monosaccharide and belongs to the group of ketohexoses with six carbon atoms; it is structurally similar to fructose. D-galactose is a monosaccharide and belongs to the group of hexoses with six carbon atoms. As a sugar, it primarily serves as a source of energy for the body's cells.
Compared to household sugar, D-galactose and D-tagatose have lower sweetening capabilities and lower calorie values. The melting point of D-galactose is around 160°C and that of D-tagatose is 130°C, making them suitable for preparing hot meals or baking.
Some key bacterial strains can utilise D-tagatose and D-galactose as food sources.