Is galactose a monosaccharide?

Sugar is an essential substance for the human body. It provides energy to the body and is the source of energy for human survival. The human body cannot absorb sugar directly, but instead breaks it down and digests it into lactose-like substances which are transported throughout the body through the blood. However, lactose is divided into several types, among which monosaccharide is the most suitable for absorption. Let’s take a look at whether galactose is a monosaccharide? I hope everyone can understand it.

Galactose (CH2OH(CHOH)4CHO) is a monosaccharide found in milk products and sugar beets. Galactose is a monosaccharide consisting of six carbons and one aldehyde group and is classified as an aldose and a hexose. Galactose is a component of lactose in mammalian milk. Polysaccharides composed of D-galactose have been found in snails, frog eggs and cow lungs. It often exists in the brain and nerve tissue in the form of D-galactoside, and is also an important component of certain glycoproteins. The monosaccharide that is absorbed fastest in the intestine is galactose.

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In the plant kingdom, galactose often exists in the form of polysaccharides in a variety of plant gums. For example, K-carrageenan in red algae is a polysaccharide composed of D-galactose and 3,6-endo-D-galactose. Free galactose is present in ivy berries. Galactose is white crystals. Both D-galactose and L-galactose occur naturally. D-galactose generally exists in milk as a structural part of lactose. The lactose in milk is broken down into glucose and galactose by the human body and absorbed and utilized.

Because it contains calories, it is also used as a nutritional sweetener. Galactose is one half of the lactose molecule, the other half is glucose. Galactose can be obtained from the hydrolysis of lactose under the catalytic action of β-lactase. Bifidobacteria ferment lactose to produce galactose, which is a component of cerebrosides in the brain and nervous system and is closely related to the rapid growth of the brain after birth.

Preparation method

The simplest method for preparing galactose is to hydrolyze lactose to obtain a mixture of equal amounts of D-galactose and D-glucose, and then remove D-glucose by fermentation to obtain pure D-galactose, generally with a very high yield. Galactose can also be prepared from D-lyxose by chemical synthesis to extend the carbon chain.