Sucrose is a disaccharide and its molecular symbol is C12H24O11. Glucose and fructose combine to form sucrose molecules. The -OH group on the 1st carbon of α-D glucose and the OH group on the 2nd carbon of β-D glucose form a glycosidic bond. A molecule of water is released during the formation of the glycosidic bond. As a result, aldehyde and ketone groups are destroyed. So while glucose and fructose are reducing sugars, sucrose is a non-reducing sugar.