A disaccharide is a sugar (a carbohydrate) composed of two monosaccharides. 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[change | change source]
|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.|