Corn (resource)
Corn, scientifically known as Zea mays, is a vital cereal crop that thrives in a range of climates, with optimal growth conditions including 50 centimeters of rainfall and temperatures between 21° and 26° Celsius. It is a significant nutritional resource in the Western Hemisphere, serving multiple purposes as human food, livestock feed, and various industrial applications. Corn has a rich history, believed to have evolved from a wild grass called teosinte in ancient Mexico, and it rapidly spread across the globe after being introduced to Europe by Christopher Columbus in 1493.
There are several varieties of corn, including dent, flint, flour, pop, and sweet corn, each with unique characteristics and uses. The most commercially important is dent corn, while sweet corn is popular for fresh consumption. Corn processing methods include wet milling, dry milling, and fermentation, leading to a wide array of derivatives such as corn syrup, cooking oils, adhesives, and even biodegradable products. Its versatility underscores its importance in both agriculture and industry, making corn a cornerstone of the global economy.
Corn (resource)
Where Found
Corn grows as far north as Canada and Siberia (roughly 58° north latitude) and as far south as Argentina and New Zealand (40° south latitude). Although adaptable to a wide range of conditions, corn does best with at least 50 centimeters of rainfall (corn is often irrigated in drier regions) and daytime temperatures between 21° and 26° Celsius. Much of the United States meets these criteria, hence its ranking as the top corn-producing country in the world in 2022.
Primary Uses
Corn is the most important cereal in the Western Hemisphere. It is used as human food, as livestock feed, and for industrial purposes.
Technical Definition
Corn (Zea mays) is a coarse, annual plant of the grass family. It ranges in height from 1 to 5 meters, has a solid, jointed stalk, and grows long, narrow leaves. A stalk usually bears one to three cobs, which develop kernels of corn when fertilized.
Description, Distribution, and Forms
Corn no longer grows in the wild; it requires human help in removing and planting the kernels to ensure reproduction. In the United States and Canada, “corn” is the common name for this cereal, but in Europe, “corn” refers to any of the small-seeded cereals, such as barley, wheat, and rye. “Maize” (or its translation) is the term used for Zea mays in Europe and Latin America.
History
Christopher Columbus took corn back to Europe with him in 1493, and within one hundred years, it had spread through Europe, Asia, and Africa. Reportedly, a corn crop is harvested somewhere in the world each month.
Corn’s exact origins remain uncertain, but most scholars agree that it is closely linked to a grass called teosinte, which is native to Mexico. Through unknown means, a wild corn evolved with tiny, eight-rowed “ears” of corn about 2 centimeters long. Corncobs and plant fragments from this wild corn have been dated to 5200 BCE. By 3400 BCE, the fossil record shows a marked change in corn, notably increased cob and kernel size, indicating greater domestication. Fully domesticated corn (which could not survive without human help) replaced the wild and other early types of corn by 700 CE.
Extensive attempts at hybridization began in the late nineteenth century, but the increase in yield was usually a disappointing 10 percent or so. By 1920, researchers had turned to inbreeding hybridization programs. In these, corn is self-fertilized, rather than being allowed to cross-pollinate naturally. Following a complex sequence of crossing and testing different varieties, the lines with the most desirable traits were put into commercial use, and they often produced 25 to 30 percent gains in yield. Although these early hybrids focused on increasing the yield, researchers later began to look for insect-resistant and disease-resistant qualities as well. One of the hybridizers of the 1920s was Henry A. Wallace, founder of Pioneer Seed Company (the world’s largest seed company) and later U.S. vice president under Franklin D. Roosevelt. By the 1950s, hybrid corn varieties were in widespread use.
Obtaining Corn
Corn processing takes place in one of three ways: wet milling, dry milling, or fermentation. In wet milling, corn is soaked in a weak sulfurous acid solution, ground to break apart the kernel, and then separated. The resulting by-products are found nearly everywhere. Dry milling is a simpler process, involving the separation of the hull from the endosperm (the food storage organ, which is primarily starch in most corn) and the germ (the plant embryo) by repeated grinding and sieving. Fermentation of corn changes the starch to sugar, which is then converted by yeast to alcohol. The process eventually results in ethyl alcohol, or ethanol (which is blended with gasoline to reduce carbon monoxide emissions), acetone, and other substances.
Uses of Corn
The types of corn still in use are dent, flint, flour, pop, and sweet. Dent corn, characterized by a “dent” in the top of each kernel, is the most important commercial variety. Flint corn tends to be resistant to the rots and blights known to attack other types; it is also more tolerant of low temperatures and therefore appears at the geographical edge of corn’s range. Flour corn is known for its soft kernel, making it easier to grind into flour and thus popular for hand-grinding. A mainstay at American movie theaters and as a snack food, popcorn will, with an optimum moisture content of about 13 percent, explode to as much as thirty times its original volume when heated. Also popular in the United States and eaten fresh, sweet corn is so named because, unlike other types, most of the sugars in the kernel are not converted to starch.
Commercially, corn is used mostly for livestock feed and industrial processing. It is high in energy and low in crude fiber but requires supplements to make a truly good feed. Industrial processing creates a great variety of products found in everyday life—underscoring the importance of corn to the world’s economy. As a renewable resource, it is also used to create biodegradable products such as plastic alternatives, cornstarch based packing peanuts, and ethanol, which help to protect the planet.
The cornstarch from wet milling supplies corn syrup (it is sweeter than sugar and less expensive, and billions of dollars’ worth is produced for soft drink manufacturers each year), starches used in the textile industry, ingredients for certain candies, and substances used in adhesives, to name a few. Other by-products provide cooking oil; oil used in mayonnaise, margarine, and salad dressing; soap powders; and livestock feed. Dry milling produces hominy, grits, meal, and flour, all of which are used for human consumption.
Bibliography
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Pollan, Michael. “Industrial Corn.” In The Omnivore’s Dilemma: A Natural History of Four Meals. New York: Penguin Press, 2006.
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Warman, Arturo. Corn and Capitalism: How a Botanical Bastard Grew to Global Dominance. Translated by Nancy L. Westrate. Chapel Hill: University of North Carolina Press, 2003.
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