Carbohydrates Classifications

Carbohydrates are the organic molecules that are composed of elements carbon, hydrogen  and oxygen. These carbohydrates are referred to as saccharides. Carbohydrates are defined as polyhydroxy-aldehydes or polyhydroxy ketones or compounds, which produce them on hydrolysis. They supply energy and serve as structural constituents.

Carbohydrates have the general formula Cx(H2O)y. They are the ultimate source of most of our food. We clothe ourselves with cellulose in the form of cotton, linen and rayon. We build furniture and houses from cellulose in the form of wood.

Carbohydrates classifications

Carbohydrates classification are explained into three groups based on the number of sugar units and upon their behaviour towards hydrolysis. They are

  1. Monosaccharides
  2. Oligosaccharides and
  3. Polysaccharides.

1.Monosaccharides :

These are simplest group of carbohydrates and are referred as simple sugars as they are sweet in taste. They cannot be further hydrolyzed to simpler compounds. They have the general formula Cn(H2O)n. Examples: Glucose and fructose.

Read this: What Happened When Fructose Overload in our Body? (Infographics)

Depending upon the total number of carbon atoms in monosaccharides and aldehyde and ketone functional groups present they are classified using terms shown in the below table.

Carbohydrates Classifications

2. Oligosaccharides:
These carbohydrates liberate two to ten monosaccharide molecules on hydrolysis. They are further classified as disaccharides, trisaccharides, tetrasaccharides, etc. based on the number of monosaccharide units. For e.g., disaccharides like sucrose produce two molecules of monosaccharides on hydrolysis. A trisaccharide like Raffinose on hydrolysis gives glucose, fructose and galactose.

3.Polysaccharides:

These carbohydrates liberate a large number of monosaccharide molecules on hydrolysis. They are usually amorphous, insoluble in water and tasteless and are called non-sugars. They are again sub-divided into two types. They are homopolysaccharides and heteropolysaccharides.

a. Homopolysaccharides: They possess only a single type of monosaccharide units. Examples: Starch, cellulose and glycogen.
b. Heteropolysaccharides: They possess two or more types of monosaccharide units. Examples: Heparin and chondroitin sulphate.

Carbohydrates may also be classified as either reducing or non-reducing sugars.

Reducing Sugars: All those carbohydrates which contain free aldehyde or ketonic group and reduce Fehling’s solution and Tollen’s reagent referred to as reducing sugars.

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Non-Reducing Sugars: All monosaccharides whether aldose or ketose are reducing sugars. In disaccharides if the reducing group of monosaccharides i.e., aldehydic or ketonic groups are bonded, these are non reducing sugars e.g., sucrose, while others in which these functional groups are free are reducing sugars. Examples: Maltose and lactose.

The above Carbohydrates classification is universal accepted classification. If you have any doubts about this please use the below comment box (or) use Contact Us form.

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