Disaccharide

A disaccharide or biose is the carbohydrate formed when two monosaccharides undergo a condensation reaction which involves the elimination of a small molecule, such as water, from the functional groups only. Like monosaccharides, disaccharides form an aqueous solution when dissolved in water. Three common examples are sucrose, lactose, and maltose.

Classification

There are two separate sorts of disaccharides: lessening disaccharides, in which one monosaccharide, the decreasing sugar, still has a free hemiacetal unit; and non-diminishing disaccharides, in which the parts security through an acetal linkage between their anomeric focuses and none, of these monosaccharide has a free hemiacetal unit. Cellobiose and maltose are illustrations of lessening disaccharides. Sucrose and trehalose are cases of non-lessening disaccharides.

Properties

The glycosidic bond can be formed between any hydroxyl group on the component monosaccharide. So, even if both component sugars are the same (e.g., glucose), different bond combinations (regiochemistry) and stereochemistry (alpha- or beta-) result in disaccharides that are diastereoisomers with different chemical and physical properties.
Depending on the monosaccharide constituents, disaccharides are sometimes crystalline, sometimes water-soluble, and sometimes sweet-tasting and sticky-feeling.