Navigation Links

Starch is a complex carbohydrate which is insoluble in water. Starch (in particular cornstarch) is used in cooking for thickening sauces. In industry, it is used in the manufacture of adhesives, paper, and textiles.



In biochemistry, starch is a mix of two polymeric carbohydrates (polysaccharides) called amylose and amylopectin, in which the monomers are glucose units joined to one another head-to-tail forming alpha-1,4 linkages. The overall structure of amylopectine is not, however, simply a linear polysaccharide chain, since occasionally, two glucose units are joined to one in an alpha-1,6 linkage, forming a branch point. Structurally, the starch forms clusters of linear polymers, where the alpha-1,4 linked chains form linear columns of glucose units branching at the alpha-1,6 links. The relative content of amylose and amylopectin varies between species. The primary function of starch is to act as an energy storage molecule for the organism. In plants starch for storage is produced in specialized cellular organs, amyloplasts.

Starch is often found in the fruit, seeds, or tubers of plants. The four major resources for starch production and consumption in the USA are corn, potatoes, rice, and wheat. As an additive for food processing you will find; arrowroot, guar gum, locust bean, and tapioca commonly used as well. Commonly used starches around the world are: arracacha, buckwheat, cassava, konnyaku, kudzu, oca, and sago.

When a starch is pre-cooked it can then be used to thicken chilled foods. This is referred to on packaging as modified food starch. Agar, carrageenan, gelatins and pectins are used in very much the same way.


Clothing starch or laundry starch is a liquid that is prepared by mixing a vegetable starch in water (earlier preparations also had to be boiled), and is used in the laundering of clothes. During the 19th century and early 20th century, it was stylish to stiffen the collars and sleeves of men's shirts and the ruffles of girls' petticoats by applying starch to them as the clean clothes were being ironed.

Aside from the smooth, crisp edges it gave to clothing, it served a practical purpose as well. Dirt and sweat from a person's neck and wrists would stick to the starch rather than fibers of the clothing, and would easily wash away along with the starch. Then, after each laundering, the starch would be reapplied.


Animal starch is the common name of glycogen. It is not the same as ordinary starch.

Tests for Starch

A solution of Iodine and Potassium iodide in water, when added to a sample containing starch (specifically amylose) will turn an intense blue-black colour, otherwise it will stay yellow-orange.

Under the microscope, starch grains show a distinctive Maltese Cross effect (also known as 'extinction cross') under polarised light.

External links


(Date:9/1/2014)... Mass-- Conventional wisdom has long held that corals ... coral reefs are passive organisms that rely ... such as nutrients and oxygen. But now scientists ... (WIS) in Israel have found that they are ... water into turbulent patterns that greatly enhance their ...
(Date:9/1/2014)... About 50 years ago, electron microscopy revealed the presence ... around and disappear. But scientists still don,t know what ... of proteins are believed to be crucial to the ... new approach to disease treatment., In the Journal ... call to investigators from various backgrounds, from biophysics to ...
(Date:8/31/2014)... A new blood test provides a fast and ... new proof-of-concept study shows. The newly developed test ... to detect active tuberculosis in children. The test ... tests in combination with speed of a blood ... for the diagnosis of tuberculosis in children, particularly ...
Breaking Biology News(10 mins):Nature's tiny engineers 2Nature's tiny engineers 3Scientists call for investigation of mysterious cloud-like collections in cells 2New tuberculosis blood test in children is reliable and highly specific 2
... German . , EASY-HIT** is a new cell-based ... This system was developed under the leadership of Professor Ruth ... the system are cultured human cells that allow HIV to ... producing a red fluorescent protein. The EASY-HIT technology can be ...
... Colo. (December 1, 2010) A major new study ... fetus to those smells and flavors, but physically changes the ... the future. "This highlights the importance of eating ... and nursing," said Josephine Todrank, PhD, who conducted the two-year ...
... from the UC Davis Health System have found that ... are significantly reduced in patients in the Sacramento area ... that affects about one in three U.S. adults and ... The study is the first to examine vitamin-D ...
Cached Biology News:A powerful new technology to identify HIV inhibitors 2Study shows pregnant mother's diet impacts infant's sense of smell 2Study finds low vitamin-d levels in northern California residents with metabolic syndrome 2Study finds low vitamin-d levels in northern California residents with metabolic syndrome 3Study finds low vitamin-d levels in northern California residents with metabolic syndrome 4
Other biology definitionOther Tags