Starch is one of the most common types of carbohydrates found in potatoes, cassava, wheat, rice and corn. It is also known as amylum and comprises a huge number of glucose units held close by glycosidic bonds. In its pure form, this carbohydrate is white in color and has no taste or odor. Pure starch is in powdered form and does not dilute in alcohol or cold water. Starch is consumed all over the world due to its easy availability. Also, it is richer in nutrition than protein and is available at a cheaper price. There are two types of molecules present in the starch, namely, branched amylopectin and amylose. The content of both molecules differ and is usually in the ratio of eighty is to twenty. Starch is used by the plants as a source of energy. The processing of starch is commonly done for the production of sugar. It is also used a binding, stiffening and thickening agent.
The word starch is said to have originated from the word “sterchen” which means “to stiffen.” Amylum is a Latin name for starch and means “not ground at a mill”. In biochemistry, amylum is used as a root for several starch related compounds.
The first grains of starch from Typha rhizomes were identified as flour 30,000 years ago in Europe. The paste of wheat starch was used for binding papyrus in Ancient Egypt. The first mention of starch extraction was done in the Natural History of Pliny by Pliny the Elder in around 77- 79 AD.
In Rome, starch was used as a component of cosmetic creams, and as a thickener for sauces. In India and Persia, starch was used as a culinary ingredient and was used for making halwa dishes, a type of desserts.
From 700 AD, starch was started being used in China for producing paper.
The records of 2008 reveal that approximately 66 million tons of starch was produced worldwide in the given year.
Starch is commonly found in foods such as cereals and root vegetables. It is present in rice, maize and wheat. Also, in root vegetables such as potato and cassava, it is found in abundance. Besides, it is also present in foods such as banana, colacasia, sorghum, millet, arrowroot, barley, sago, oats, sweet potatoes, yams, rye, water chestnuts and beans such as lentils, fava beans, mung beans, chick peas and beans. Additionally, it is also there in prepared foods such as tortilla, cereals, noodles, bread, pasta and porridge.
The production of starch is usually done by extracting the starch from roots, tubers and seeds and then refining them. The extraction of starch is done from more than 50 plant types. Wet grinding, rinsing, sieving and drying are some of the methods involved in starch extraction. Potato starch, tapioca starch, corn starch and wheat starch are some of the major commercially refined starches. Rice starch, sago starch and sweet potato starch are also used at many places.
- Food processing -Starch is commonly used as a food additive while processing of foods. The starch is used for preparation of foods like noodles and pasta
- Thickening agent –The food starches are primarily used for thickening and stabilizing the foods such as gravies, puddings, custards.
- For making gummed sweets – The conventional method of making gummed sweets like wine gums and jelly beans calls for the starch being used as one of the major ingredients.
One of the most common industrial uses of starch is in the non-food industry, which is as follows –
- Pharmaceutical industry – Starch is often used as a binder or disintegrator in the pharmacy industry.
- Papermaking – Besides being used a culinary ingredient, starch is used largely bythe paper making industry. The industry makes use of both modified and unmodified forms of starch. An usual sheet of notebook paper may content 8 percent starch.
- Adhesive for corrugated boxes – Nonfood starches are often used for gluing the corrugated boxes.
- For laundry purpose – Laundry starch is used widely as a cloth stiffener and is prepared by mixing vegetable starch in water.