01 February 2011


What are Carbohydrates?

Carbohydrates are the main source of energy in our body. Carbohydrates are saccharides or sugar which breaks down in the living bodies to release energy. This organic molecule is present in most of the foods. Carbohydrate happens to be the most abundant amongst the important classes of bio-molecules which include lipids, proteins and nucleic acids. Carbohydrates break down immediately to release energy when you are physically active. When the body is not active, Carbohydrates is stored as fat in the body for later use.

Types of Carbohydrates

Carbohydrates can be classified into the following types:
  • Monosaccharides - Monosaccharide means one sugar.
    Examples: galactose, fructose and glucose, fructose. The chemical composition of carbon, hydrogen and oxygen in monosaccharides is in the ratio of 1:2:1.
  • Disaccharides - Disaccharides which means"two sugars. They are formed by glycosidic bonding.
    Examples: maltose, lactose and sucrose
  • Oligosaccharides - These are simple sugars with 3-10 sugar units.
    Examples: stachyose and raffinose
  • Polysaccharides - These are simple sugars with over 3000 sugar units.
    Examples: amylose and amylopectin
  • Nucleotides - These sugars are found in the form of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
    Examples: DNA and RNA

Chemistry of Carbohydrates

Carbohydrate is called in several general names like starch, sugar, saccharide and polysaccharide. Carbohydrate is the name given to "hydrate of carbon". The general formula for carbohydrate is Cx(H2O)y - x. The most common form of carbohydrate is glucose whose chemical formula is C6 (H2O) 6, also written as C6H12O6. The chemistry of carbohydrates is similar to aldehydes, ketones and alcohols.
Carbohydrate is chemically ketone or polyhydroxy aldehyde. Carbohydrate may appear in a straight chain or also in the form of a ring structure. Ring structures feature two acetal or hemiacetal functional groups. Photosynthesis is the process through which carbon dioxide is converted to carbohydrates.

Role of Carbohydrates

In Animals:
  • The most important function of carbohydrates is production of energy. One gram of carbohydrates is equivalent to four calories. They are the best source of instant energy. They provide you with the necessary energy for carrying out physical exercises.
  • Carbohydrates store food in the body in the forms of starch or glycogen and combine with nitrogen when non-essential amino acids are formed.
  • Carbohydrates promote health fitness and build up body strength with the generation of energy.
  • Carbohydrates in the form of fiber keep the bowel function smooth.
  • This macronutrient also regulates blood glucose level in the body and prevents ketosis. It also controls insulin metabolism
  • Carbohydrates also aids in Protein glycosylation, cholesterol and triglyceride metabolism and Bile acid dehydroxylation.
In Plants:
  • In plants, Carbohydrates form the building blocks. This is because they form the cellulose which gives structure and strength to the plants.

Source of Carbohydrates

The plant based foods are the richest source of Carbohydrates. Here is a list of foods with high and low content of carbohydrate per 100 gm of the edible portion. These are some of the items recommended by the nutritionists in India:

High Carbohydrate Content:

Food Item Carbohydrate Content (in gm)
Green gram 59.9
Rajma 60.6
Bengal whole gram 60.9
Whole wheat flour 69.4
Jowar 72.6
Dry Apricot 73.4
Raw Rice 78.2
Honey 79.5
Jaggery 95
Sugarcane 99.4

Low Carbohydrate Content:

Food Item Carbohydrate Content (in gm)
Butter milk 0.5gms
Fish 2gms
Cucumber 2.5gms
Curd 3.0gms
Cauliflower 4gms
Ladies finger 6.4gms
Beet root 8.8gms
Musambi 9.3gms

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