What is galactose in chemistry


Generally: D-galactose (mucous sugar) is created when -> lactose (milk sugar) is broken down after it is absorbed through dairy products. It is metabolized in the liver to -> glucose. Various algae ingredients that are used as thickeners in the food industry also consist of the basic building block galactose and related substances that form mucilage as long-chain polysaccharides (galactans) in the cell walls of the algae.

Dietetics: Galactose has no effect on insulin release. After ingestion, it reaches the liver very quickly and almost completely. In the case of a congenital galactose metabolic disorder (galactosemia), there is a lack of an enzyme that converts galactose into glucose. As a result, the sugar is converted into a sugar alcohol (galactitol), which is toxic to the nervous system. Infants with galactose intolerance cannot tolerate breast milk or conventional baby milk products, as the lactose present there is broken down into harmful galactose and glucose. The diet can be switched to soy milk-based, for example.

Chemistry: Chemically, galactose is a stereoisomer of glucose and is also one of the hexoses with the empirical formula C.6H12O6.
In aqueous solution, as with -> glucose, there is sometimes an intramolecular ring closure, so that an equilibrium is established between the chain shape and the two ring shapes (furanose form and pyranose form). In galactans (mucilage of algae, see) L-galactose also occurs, which is arranged in a mirror image. (L means left-handed in the Fischer projection and R means right-handed).

Use: Galactose is almost exclusively used clinically, so it occurs e.g. in parenteral nutrition (artificial nutrition directly into the bloodstream) for certain purposes.