Sucrose

Sucrose is a disaccharide composed of one glucose unit and one fructose unit joined by a glycosidic bond. It is commonly known as table sugar and occurs naturally in many plants. Because it contains two linked monosaccharides, sucrose must be hydrolyzed into its component sugars before they can be absorbed from the intestine .^1,2

Digestion of sucrose occurs mainly at the brush border of the small intestine. Sucrase, an enzyme within the sucrase-isomaltase complex on enterocytes, hydrolyzes the bond joining glucose and fructose. The released glucose and fructose are then available for intestinal absorption .²

Sucrose is chemically distinct from free glucose and fructose because its two sugar units are covalently linked. It is also distinct from high-fructose corn syrup, which contains glucose and fructose mainly as separate monosaccharides in solution. Once sucrose has been hydrolyzed during digestion, however, it yields the same two monosaccharides, glucose and fructose .^1,2

Sucrose is classified as a nonreducing sugar because the anomeric carbons of both glucose and fructose participate in the glycosidic bond, leaving neither available as a free reducing group. This structural feature distinguishes sucrose from reducing disaccharides such as lactose and maltose .¹