Short Note on Starch

Topics: Starch, Maize, Glucose Pages: 12 (3440 words) Published: August 21, 2012
From Wikipedia, the free encyclopedia

CAS number


RTECS number
Molecular formula
Molar mass
Appearancewhite powder
1.5 g/cm3
Melting point
Solubility in water
ICSC 1553

EU Indexnot listed
410 °C
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)

Infobox references

Structure of the amylose molecule

Structure of the amylopectin molecule

Granules of wheat starch, stained with iodine, photographed through a light microscope Starch or amylum is a carbohydrate consisting of a large number of glucose units joined by glycosidic bonds. This polysaccharide is produced by all green plants as an energy store. It is the most common carbohydrate in the human diet and is contained in large amounts in such staple foods aspotatoes, wheat, maize (corn), rice, and cassava. Pure starch is a white, tasteless and odorless powder that is insoluble in cold water or alcohol. It consists of two types of molecules: the linear andhelical amylose and the branched amylopectin. Depending on the plant, starch generally contains 20 to 25% amylose and 75 to 80% amylopectin by weight.[1] Glycogen, the glucose store of animals, is a more branched version of amylopectin. Starch is processed to produce many of the sugars in processed foods. Dissolving starch in warm water gives wheatpaste, which can be used as a thickening, stiffening or gluing agent. The biggest industrial non-food use of starch is as adhesive in the papermaking process. Contents

1 Name
2 History
3 Energy store of plants
o3.1 Biosynthesis
4 Properties
o4.1 Structure
o4.2 Hydrolysis
o4.3 Dextrinization
o4.4 Chemical tests
5 Food
o5.1 Starch industry
5.1.1 Starch sugars
5.1.2 Modified starches
5.1.3 Use as food additive
6 Industrial applications
o6.1 Papermaking
o6.2 Corrugated board adhesives
o6.3 Clothing starch
o6.4 Other
7 See also
8 References
9 External links

The word "starch" is derived from Middle English sterchen, meaning to stiffen. "amylum" is Latin for starch, from the Greek αμυλον, "amylon" which means "not ground at a mill". The root amyl is used in biochemistry for several compounds related to starch. [edit]History

Starch grains from the rhizomes of Typha (cattails, bullrushes) as flour have been identified from grinding stones in Europe dating back to 30,000 years ago.[2] Pure extracted wheat starch paste was used in Ancient Egypt possibly to glue papyrus.[3] The extraction of starch is first described in theNatural History of Pliny the Elder around AD 77-79.[4] Romans used it also in cosmetic creams, to powder the hair and to thicken sauces. Persians and Indians used it to make dishes similar to gothumai wheat halva. Rice starch as surface treatment of paper has been used in paper production in China, from 700 AD onwards.[5] In addition to starchy plants consumed directly, 66 million tonnes of starch were being produced per year world-wide by 2008. In the EU this was around 8.5 million tonnes, with around 40% being used for industrial applications and 60% for food uses,[6] most of the latter as glucose syrups.[7] [edit]Energy store of plants

This section does not cite anyreferences or sources. (March 2012)

In photosynthesis, plants use light energy to produce glucose from carbon dioxide. The glucose is stored mainly in the form of starch granules, inplastids such as chloroplasts and especially amyloplasts. Toward the end of the growing season, starch accumulates in twigs of trees near the buds.Fruit, seeds, rhizomes, and tubers store starch to prepare for the next growing season. Glucose is soluble in water, hydrophilic, binds much water and then takes up much space; glucose in the form of...
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