Corn starch

Corn starch, cornstarch, cornflour or maize starch or maize is the starch derived from the corn (maize) grain. The starch is obtained from the endosperm of the corn kernel. Corn starch is a popular food ingredient used in thickening sauces or soups, and is used in making corn syrup and other sugars.

History

Advertisement for a Cornflour manufacture, 1894

Cornstarch was discovered in the year 1840 by Thomas Kingsford, whilst he was working as the superintendent of a wheat starch factory in Jersey City, New Jersey. Until 1851, corn starch was used primarily for starching laundry and industrial uses.

Use

Corn starch is used as a thickening agent in liquid-based foods (e.g., soup, sauces, gravies, custard), usually by mixing it with a lower-temperature liquid to form a paste or slurry. It is sometimes preferred over flour alone because it forms a translucent mixture, rather than an opaque one. As the starch is heated, the molecular chains unravel, allowing them to collide with other starch chains to form a mesh, thickening the liquid (Starch gelatinization).

It is usually included as an anti-caking agent in powdered sugar (10X or confectioner's sugar). Baby powder often includes cornstarch among its ingredients.

Corn starch when mixed with a fluid can make a non-Newtonian fluid, e.g. adding water makes Oobleck and adding oil makes an Electrorheological fluid.

A common substitute is arrowroot, which replaces corn starch on a 1:1 ratio.

Corn starch added to a batter which coated chicken nuggets increased oil absorption and crispness after the latter stages of frying.

Corn starch can be used to manufacture bioplastics.

Corn starch is the preferred anti-stick agent on medical products made from natural latex, including condoms, diaphragms and medical gloves. Prior usage of talc was abandoned as talc was believed to be a carcinogen.

Food producers reduce production costs by adding varying amounts of corn starch to foods, for example to cheese and yogurt. This is more common in the United States of America where the Congress and the Department of Agriculture subsidize and reduce its cost to food manufacturers.

Corn starch is used to supply glucose to humans who have glycogen storage disease (GSD). Without this, they would not thrive (i.e. little, if any, weight gain) and thus die. Cornstarch can be used starting at age 6 – 12 months which allows feeds to be spaced and glucose fluctuations to be minimized.

Manufacture

Corn starch shown on a poster, upper left.

The corn is steeped for 30 to 48 hours, which ferments it slightly. The germ is separated from the endosperm and those two components are ground separately (still soaked). Next the starch is removed from each by washing. The starch is separated from the corn steep liquor, the cereal germ, the fibers and the corn gluten mostly in hydrocyclones and centrifuges, and then dried. (The residue from every stage is used in animal feed and to make corn oil or other applications.) This process is called wet milling. Finally, the starch may be modified for specific purposes.

Accident

On June 27, 2015, flammable starch-based powder fuelled the Formosa Fun Coast explosion in Taiwan.

Names and varieties

• Called corn starch in the United States and Canada.
• Called cornflour in the United Kingdom, Ireland, Israel and some Commonwealth countries. Not to be confused with cornmeal.
• Often called maizena in the Netherlands, Belgium, France, Germany, Finland, Austria, Italy, Portugal, Morocco, Brazil, Norway, Denmark, Slovakia, Sweden, Switzerland, Spain, South Africa and Latin America, after the brand.

See also

• Amylomaize, high amylose starch
• Bird's Custard, the English custard based on cornflour, invented in 1837
• Waxy corn, waxy maize starch
• Corn syrup
• Corn ethanol
• Modified starch
• Potato starch
• Tapioca starch

External links

• American Corn Refiners Association