Products
Pure galactose is available in specialty stores, such as pharmacies and drugstores. The name is derived from the Greek name for milk (galactos).
Structure and properties
The D-galactose (C6H12O6, Mr = 180.2 g/mol) exists as a white, crystalline or fine-grained powder and is readily soluble in water. It is a monosaccharide and an aldohexose (a carbohydrate). Lactose (milk sugar) is a disaccharide consisting of one molecule of galactose and one molecule of glucose covalently linked β-1,4-glycosidically. It is also present in oligosaccharides such as raffinose, polysaccharides, glycoproteins and glycolipids. Lactose is broken down in the intestine by the enzyme lactase into its components, which are absorbed. In lactose intolerance, there is not enough lactose and lactase is bacterially fermented in the intestine, causing gastrointestinal disorders. It is utilized by humans and can also be biosynthesized by humans. It plays an important role in the nutrition of infants and young children.
Effects
Galactose has only about 65% of the sweetening power of sucrose (table sugar). It can be metabolized by the body and has a calorific value of over 400 kcal per 100 g.
Areas of application
As an energy supplier and sweetener.
Cf.
Carbohydrates, monosaccharides, lactose, lactase, lactose intolerance.
