Classification of Carbohydrate

A. Monosaccharides:

• Simple form of sugar and can’t be hydrolyzed into smaller unit.

a. Trioses: Has 3 carbon atoms. Eg: Glycerol dehyde, dihydroxy acetone.

b. Tetrose: Have 4 carbon atoms. Eh: Erythrose.

c. Pentose: Having 5 carbon atoms.

• Arbinose: Component of hemicelluloses and found in silage as result of hydrolysis.
• Xylose: Forms the main chain of grass hemicelluloses and xylose along with arabinose.
• Ribose: Present in all living cells as constitute of RNA and component of several vitamins and co-enzymes.

d. Hexoses:

I. Glucose: Sugar occurs in free plants fruits, honey and oilier body fluid and is soluble in water.

ii. Fructose: Known as fruit sugar occurring in green leaves, fruits and honey.

iii. Mannose: Doesn’t occur free in nature, found in polymerized form as mannose.

Galactose: Constituent of disaccharide lactose which occur in milk and component of gum, mucilage, pigment, etc and doesn’t exist free in nature.

B. Oligosaccharide: Most frequently occurring CHO and produces two molecules of simple sugar after hydrolysis.

1. Sucrose: Found in carrot, fruits and beet sugar.
2. Lactose: Also known as milk sugar and is not soluble as sucrose and is less sweet. On hydrolysis produces one molecule of glucose and one molecules of galactose.
3. Maltose: Produced from starch during the germination of barley and on hydrolysis produces two molecules of glucose.
4. Cellobiose: Is the repeating unit of cellulose and is less soluble and less sweet.
5. Trehalose: Is disaccharides present in fungi and sea weeds.
6. Raffinose: Is trisaccharide and on hydrolysis produces glucose, fructose and galactose.
7. Stachyose: Occurs in seed of legumes, on hydrolysis produces two molecules of galactose, one molecule of glucose and one molecule of fructose.

C. Polysaccharide:

Starch: After hydrolysis change to dextrin, maltose and finally to glucose.

Glycogen: Is main CHOs storage products in animal body and play important role in energy metabolism.

Dextrin: Intermediate product of starch and glucose.

Cellulose: Occurs in nearly pure form in cotton and less digested in non-ruminant but digested in ruminant by microorganism and end product is VFA like acetic propionic and butyric.

Hemicelluloses: Are water insoluble and less resistance chemical agent than cellulose, they form leafy and woody structure of plant.

Pectin: Found in peel of citrus, sugar beet pulp and used as jam making.

Chitin: Major constituent of exoskeleton of insect.

Inulin: Storage form of CHO and after hydrolysis produces fructose.

Lignin: Closely associated with cellulose and is indigestible by animal.