Galactose
Galactose is a simple sugar or monosaccharide made up of six carbon atoms or hexose, which is converted into glucose in the liver for energy. In addition, it is part of the glycolipids and glycoproteins of cell membranes, especially neurons.
From a chemical point of view it is an aldose, that is, its functional chemical group is an aldehyde (CHO) located on carbon 1, or anomeric carbon. On the other hand, like glucose, it belongs to the group of hexoses, which are monosaccharides (simple carbohydrates) formed by a chain of six carbon atoms. Its molecular or empirical formula is the same as that of glucose: C6H12O6, although it differs from it because it is an epimer of glucose on Carbon number 4, that is, the alcohol group on this carbon is directed to the left (in the linear formula, in the cyclic form it is directed upwards). Galactose is a pyranose, since it can theoretically be derived from the six-sided ring made up of 5 carbon atoms and 1 oxygen, called a pyran. Therefore, in its cyclic form it will be called galactopyranose, with the β form existing if the -OH attached to the anomeric carbon is facing up, and the α form if the -OH attached to the anomeric carbon is facing down. In the same way, there is the D form and the L form, the first being the most abundant naturally.
Galactose is synthesized by the mammary glands to produce lactose, which is a disaccharide formed by the union of glucose and galactose, therefore the greatest contribution of galactose in nutrition comes from the intake of lactose from milk.