Carbohydrate Properties

The term carbohydrate literally means ‘carbon + water’ and partially describes its chemical makeup. All carbohydrates contain carbon, hydrogen and oxygen and are typically found in a ration of 1:2:1 resulting in the chemical formula (CH2O)n.

The modern definition of carbohydrate is that it is a polyhydroxy aldehyde or ketone, or a compound that can be derived from them by any of several means including
1. Reduction to give sugar alcohols
2. Oxidation to give sugar acids
3. Substitution of one or more of the hydroxyl groups by various chemical groups
4. Derivation of the hydroxyl groups by various moieties

Carbohydrates are also called saccharides (from the Greek word ‘sakcharon’ meaning sugar) and are usually divided into three groups: monosaccharides, disaccharides and polysaccharides.

The term monosaccharide refers to a carbohydrate derivative possessing a single carbon chain. Since monosaccharides are polyhydroxylated aldehydes and polyhydroxylated ketones, all can be divided broadly into:
1. Aldoses
2. Ketoses
The most common monosaccharides are glucose, fructose and galactose.

Disaccharide and disaccharide refer to molecules containing two or three such monosaccharides units joined.

Oligosaccharide and polysaccharide refer to larger such aggregates with a few and many monosaccharide units, respectively.

Carbohydrate posses a large number of functionalities, at least one carbonyl and several hydroxyl functions per monosaccharide and often carry further kinds of functional groups.

They are compounds with several stereocenters and thus the carbohydrate group consists of a large number of stereoisomers.
Carbohydrate Properties