Disaccharide

A disaccharide is a sugar (a carbohydrate) composed of two monosaccharides, such as glucose and fructose that make up the disaccharide sucrose. It is formed when two sugars are joined together and a molecule of water is removed. Due to this, disaccharides cannot hydrolyse, meaning their molecules are unable to be broken down through a reaction with water. For example, milk sugar (lactose) is made from glucose and galactose whereas cane sugar (sucrose) is made from glucose and fructose. 
 Common disaccharides 

 Disaccharide  Unit 1  Unit 2  Bond  Notes
   Sucrose (table sugar, cane sugar, saccharose, or beet sugar)   glucose  fructose  α(1→2)  Sucrose is found naturally in many food plants.
   Lactose (milk sugar)  galactose   glucose  β(1→4)  Lactose is found in milk products.
   Maltose   glucose   glucose   α(1→4)  Produced during the malting of barley 
   Trehalose    glucose   glucose   α(1→1)α  Present in fungi and insects. Successfully produced at an industrial scale by enzymatic treatment of starch for use as a food ingredient.
   Cellobiose  glucose   glucose   β(1→4)  -

Maltose and cellobiose are hydrolysis products of the polysaccharides, starch and cellulose, respectively.
Some common Disaccharides are:  Maltose, Lactose and Sucrose.

Category:Carbohydrates