Disaccharides consist of two monosaccharides joined by glycosidic linkage. The disaccharide maltose contains two D-glucose residues joined by a glycosidic linkage, which is a covalent bond formed by joining of –OH group of one monosaccharide with the anomeric carbon of the other sugar unit. Â
Disaccharides can be hydrolysed to yield their constituent monosaccharides by boiling with dilute acid. Hydrolysis of sucrose yields a mixture of glucose and fructose
Conventionally, oligosaccharides are carbohydrates having two to ten units of monosaccharides joined together by glycosidic bond. Some commonly occurring oligosaccharides are maltose, lactose, sucrose, etc.
- Maltose,
Sucrose and lactose are biologically
important disaccharides. Â
- Maltose: It is called malt sugar. It is produced during the
germination of starchy seeds. Two glucose molecules are joined to
form a molecule of maltose.Â
- Sucrose: It is common cane sugar or table sugar. It is formed by the union of one molecule of glucose and one molecule of fructose. It is a storage product of photosynthesis in sugar cane and sugar beet. It is the sweetest among naturally occurring sugars. Â
- Lactose: It is called milk sugar. It is made up of D-galactose and D-glucose residues.