Source of Carbohydrates – Uses and Types | Biology Ideas

Here are some Sources of Carbohydrates we are going to study…


Botanical name – Saccharum officinarum

Family – Poaceae

Part used – (Cane) stem

Type – Carbohydrate, disaccharide, sucrose

Sucrose- Glucose + Fructose

Source of Carbohydrates, sugarcane

Sugar is a sweet crystalline substance and an important source of energy in the human diet. Sugar is used in the manufacture of alcoholic beverages. Soft drinks, confectionery ice cream and chocolates. It is used as a sweetening agent in many food industries.


By-products of the sugar industry –

The sugar industry has two important by-products called bagasse after extraction of juice and second by-product molasses after crystallization and centrifugation of mother liquor.


1) Bagasse –

  • It is one of the important fibrous material left after the extraction of juice. It is used as boiler fuel for steam raising.
  • It is also used in the manufacture of low-grade paper. Bagasse is also used as insulating wallboards, fibreboard, Cardboard, plastics and furfural.
  • Furfural is important in the oil refining and nylon industries.
  • Bagasse is used as a mulch for plants and as a litter or bedding for poultry and livestock.


2) Molasses –

  • It is another significantly important by-product of the sugar industry that has great industrial value.
  • It is left after separating the sugar crystals after the centrifugation and crystallization process.
  • It contains 60% fermentable sugars and hence has great demand.
  • It is used as livestock feed.
  • It is the important raw material of distilleries of many sugar industries all over the country.
  • In this way, it is used in making alcoholic drinks such as rum and in the manufacture of a number of chemicals as industrial alcohol, vinegar, glycerol, lactic, acetic, aconitic and citric acids, monosodium glutamates, chloroform, plastics etc.


3) Press mud – 

  • The third by-product of the sugar industry is called press mud. It is used in the manufacture of polishes, cosmetics, carbon paper (coatings).



Starch consists of polysaccharide granules which on complete hydrolysis yield glucose.

Starch and amylum, both the names, have historical importance.

Starch was used for giving stiffness or strength to clothes for laundry purposes.

The German name for starch is Starke which means strength Amylum means without a mill.

In the early period, starch was prepared by softening wheat grains with water and crushing without powdering in the mill and hence the name.

Starch is the first or primary product of photosynthesis. According to its origin and size starch is either assimilatory or reserve starch.

Assimilatory starch is produced in chlorophyll-containing parts of plants like stem or leaves and consists of small granules and is again utilized in the metabolism of the plant after formation.

Reserve starch is present in non-chlorophyll parts of the plants like root, rhizome, tuber, and consists of larger granules and usually not utilized or metabolized by the plant.

Read Also: Carbohydrates | Biology Ideas | Types and Uses


Starch is obtained from,

(1) wheat
(2) maize
(3) rice and
(4) potato

The following are the botanical and geographical sources.

Wheat, maize and rice belong to the same family Gramineae.

  1. Wheat – Triticum sativum

Geographical Source: Many temperate countries of the world.

2. Maize – Zea mays

Geographical Source: U.S.A., Argentine and other tropical and sub-tropical countries.

3. Rice – Oryza sativa

Geographical Source: India, China, Japan and other tropical and subtropical countries.

4. Potato – Solanum tuberosum (Tubers)

Family – Solanaceae

Geographical Source – Many countries of the world.


Preparation of Starch –

In wheat, maize and rice starch are present in the endosperm along with the proteins, mainly gliadins and glutelins collectively known as gluten.

In the preparation of starch, it is necessary to remove the protein.

Gluten forms with water sticky, elastic mass or swells with water and can be removed by filtration.

Gluten dissolves in dilute alkali while starch is insoluble.

Starch is heavier than gluten. Thus, by filtration, solubility or centrifugation protein can be separated.


Rice Starch –

Rice starch is prepared from broken pieces of rice which remain behind after polishing rice.

Pieces of rice arc macerated with 0.5% caustic soda solution.

Gluten softens or dissolves. Rice pieces are taken out, crushed and macerated with water.

Starch is separated from the milky starchy liquid by keeping it for some time or by centrifugation.

It is then washed, dried and powdered.

This starch is composed of simple or compound grains.

Compound grains are ovoid and consist of 2 to 150 components. Individual’ grains are small usually 6µ in diameter, polyhedral with pointed angles.

A small hilum is seen in large grains.


Characters –

Starch occurs as a white powder or in irregular angular mass.

It is insoluble in cold water. Its specific gravity is 1.60 to 1.65 and thus being heavier than water it sinks in water.

One part of starch forms a colloidal solution when heated with 15 parts of water which when cooled forms translucent jelly.

With iodine reagent, it gives deep blue colour. The pH of starch depends on its composition or method of preparation.

Maize starch is neutral or slightly alkaline, rice starch is slightly alkaline while wheat and potato starches are slightly acidic.

Starch occurs in simple or compound grains. Characters of starch seen through a microscope like a shape, size, the position of hilum, striations and whether they are concentric or eccentric and in compound starch number of starch grains are characteristic for each starch.

Viewed under polarized light starch granules show a distinct black cross intersecting at the hilum.



Botanical source – Oryza sativa L.

Family – Poaceae

Part used – Grain

Type – Starch – Polysaccharide (Amylose and amylopectin)


Constituents –

Starch contains amylose or β amylose and amylopectin, which are chemically two different substances.

Amylose consists of straight-chained glucose units, present in the inner part of the granule, and is of high molecular weight and responsible for the soluble property of starch.

It is soluble in water and gives bright blue colour with iodine. Amylose undergoes hydrolysis with malt extract or β amylase and forms maltose.

Amylopectin consists of both straight as well as branched chains of glucose units, present in the outer part of granules.

It is insoluble in water and swells with water and is responsible for the gelatinizing property of the starch.

It gives bluish-black colour or precipitate with starch, Amylopectin is more, and it is responsible for the framework of the starch.

Read Also: Carbohydrates | Biology Ideas | Types and Uses


Uses –

Starch is nutritive, demulcent, protective and absorbent.

Starch is an important food of human beings and animals, and during digestion, it is converted into glucose which is absorbed in the small intestine.

Starch has demulcent action on the skin and mucous membrane.

It is used in skin irritation as a dusting powder, in swelling and inflammation.

Starch is used as an antidote in iodine poisoning.

It is used as a disintegrating agent in pills and tablets and as an indifferent diluent in solid extracts of drugs and medicinal powder.

Starch is an important diagnostic agent in the identification of crude drugs in pharmacognosy.

The chief use of rice is as food, and more people use it than any other cereal. The rice is generally eaten with pulses (legumes) or some other

food rich in proteins. A diet of rice and soybeans makes the food of millions.

The Rice straw is used for making straw boards, paper and mats.

Rice bran oil is used for making soaps and cosmetics.

Rice starch is much used in European countries.

In several tropical countries, intoxicating beverages are prepared from rice.

Important beverage of Japan, Sake is prepared by fermenting rice.

In India also in some parts of Orissa and Andhra Pradesh, intoxicating beverages are prepared from rice.



Botanical source – Acacia arabica Wild

Common name – Babul

Family – Leguminosae

Part Used – Dried gummy exudation from the stem and branches

Type – Carbohydrate- complex polysaccharide

Chemically gums are a mixture of calcium, sodium or potassium salts of aldobionic acid. Aldobionic acids on hydrolysis yield monosaccharide such as arabinose, galactose, mannose, xylose and glucuronic acid.

Uses –

Gum is used in the food industry as a stabilizer and ingredient in some foodstuffs.

It is used as an emulsifying agent in paint production.

An important ingredient in ice-creams, syrups, chocolate candies and chewing gum to prevent crystallization of sugars.

Gum is used as viscosity control in inks.

Acacia gum is used in pharmaceuticals, cosmetics and ayurvedic preparations.

It is used as a binder in fireworks and watercolours, as a lickable adhesive on postage stamps

It reduces the surface tension of liquids, which leads to increased fizzing in carbonated beverages.



  • Synonyms – Ispaghula, Isabgul, Indian Psyllium, Isabgol, flea seed.
  • The origin of the word Espagnol lies in the Persian words ISAP (the horse) and GHOL (the ear).
  • Thus, the literal meaning of the word Isapgol is the ear of the horse. The seeds, as well as, husk of the seeds, are used in medicine since the 18th century.
  • About 10 species of drugs are available in India.
  • Seeds are very small in size. One thousand seeds weigh about 1.5g. Isapgol has high export potential.

Read Also: Alkaloids | Biology Ideas | Classification and Properties


Biological Source –

Isapgol consists of dried seeds of the plant known as Plantago ovate (Syn: Plantago indica; Plantago afra) Forskal,

Family – Plantaginaceae.

Part used – In the pharmaceutical field, seeds, as well as, the dried seed coats, known as Espagnol husk, are used.


Geographical Source –

The plant is cultivated largely in Gujarat, Punjab and South Rajasthan.

The factory for the preparation of husk is located at Sidhpur in North Gujarat: In Maharashtra, it is found to be grown successfully near Pune.

About 50 thousand hectares of area is said to be under cultivation for the drug in India.

The world demand for psyllium and Espagnol seeds and husk is increasing (approx. 50,000 tonnes) and the main markets are in U.S.A., France, West Germany, and the U.K.

The export of Espagnol husk and seeds together during 1995-96 was Rs. 155 crores and during 1996-97 it was Rs. 137 crores.


Macroscopic Characters –

Colour – Pinkish-grey to brown.

Odour – None.

Size – 10 to 35 mm in length and 1 to 1.75 mm in width.

Shape – It is ovate cymbiform.

Seeds are hard, transparent and smooth with grey or reddish-brown oval spot in the centre of the convex surface.

The concave surface contains the hilum covered with a thin membrane having two perforations 1 gm. accommodates 500-600 seeds.


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