Corn is a human food product of the agricultural crop maize.

History

Research in the early 21st century indicate the Balsas River Valley of south-central Mexico as the center of domestication for the agricultural crop maize. ^[1] A 2002 study by Matsuoka et al.. demonstrated that, rather than the multiple independent domestications model, all maize arose from a single domestication event about 9,000 years ago. ^{[2] [3]}

Although maize naturally contains niacin, an important nutrient, it was not bioavailable without the process of nixtamalization. The Maya used nixtamal meal to make varieties of porridges and tamales. ^[4]

After the arrival of Europeans in 1492, Spanish settlers consumed maize products, and explorers and traders carried it back to Europe and introduced it to other countries. ^[5] Maize spread to the rest of the world because of its ability to grow in diverse climates. It was cultivated in Spain just a few decades after Columbus's voyages and then spread to Italy, West Africa and elsewhere. ^[6] Maize had many advantages over wheat and barley; it yielded two and a half times the food energy per unit cultivated area, ^[7] could be harvested in successive years from the same plot of land, and grew in wildly varying altitudes and climates, from relatively dry regions with only 250 mm (10 in) of annual rainfall to damp regions with over 5,000 mm (200 in). By the 17th century it was a common peasant food in Southwestern Europe, including Portugal, Spain, southern France, and Italy. By the 18th century, it was the chief food of the southern French and Italian peasantry, especially in the form of polenta in Italy. ^[8]

Staple food

Cornmeal (ground dried maize) constitutes a staple food in many regions of the world. Maize is used to produce cornstarch, a common ingredient in home cooking and many industrialized food products. Cornstarch can be hydrolyzed and enzymatically treated to produce syrups, particularly high fructose corn syrup, a sweetener; and also fermented and distilled to produce grain alcohol. Grain alcohol from maize is traditionally the source of Bourbon whiskey. Corn flour is used to make cornbread and other baked products.^{[ citation needed]}

Maize is a staple of Mexican cuisine. Masa (cornmeal treated with limewater) is the main ingredient for tortillas, atole and many other dishes of Central American food. It is the main ingredient of corn tortilla, tamales, pozole, atole and all the dishes based on them, like tacos, quesadillas, chilaquiles, enchiladas, tostadas and many more. In Mexico the fungus of maize, known as huitlacoche, is considered a delicacy.^{[ citation needed]}

Coarse maize meal is made into a thick porridge in many cultures: from the polenta of Italy, the angu of Brazil, the mămăligă of Romania, to cornmeal mush in the US (or hominy grits in the South) or the food called mieliepap in South Africa and sadza, nshima, ugali and other names in other parts of Africa. Introduced into Africa by the Portuguese in the 16th century, maize has become Africa's most important staple food crop. ^[9] These are commonly eaten in the Southeastern United States, foods handed down from Native Americans, who called the dish sagamite.^{[ citation needed]}

Within the United States, the usage of maize for human consumption constitutes only around 1/40th of the amount grown in the country. In the United States and Canada, maize is mostly grown to feed livestock, as forage, silage (made by fermentation of chopped green cornstalks), or grain. Maize meal is also a significant ingredient of some commercial animal food products.^{[ citation needed]}

Unripe, ripe, and dried

Corn kernels can be consumed unripe, ripe, and dried.

Maize can be harvested and consumed in the unripe state, when the kernels are fully grown but still soft. Unripe maize must usually be cooked to become palatable; this may be done by simply boiling or roasting the whole ears and eating the kernels right off the cob. Sweet corn, a genetic variety that is high in sugars and low in starch, is usually consumed in the unripe state. Such corn on the cob is a common dish in the United States, Canada, United Kingdom, Cyprus, some parts of South America, and the Balkans, but virtually unheard of in some European countries.^{[ citation needed]} Corn on the cob was hawked on the streets of early 19th-century New York City by poor, barefoot " Hot Corn Girls", who were thus the precursors of hot dog carts, churro wagons, and fruit stands seen on the streets of big cities today. ^[10]

Although maize naturally contains niacin, an important nutrient, it was not bioavailable without the process of nixtamalization. The Maya used nixtamal meal to make varieties of porridges and tamales.

^[11]

Dishes

Common dishes include corn on the cob, creamed corn, cornmeal mush, and cornbread.

Traditional Central and North American foods

Traditional dishes are often made with masa, cornmeal treated with limewater, including tortillas, atole and many other dishes of Central American food. It is the main ingredient of corn tortilla, tamales, pozole, atole and all the dishes based on them, like tacos, quesadillas, chilaquiles, enchiladas, tostadas and many more. In Mexico the fungus of maize, known as huitlacoche, is considered a delicacy.^{[ citation needed]}

Foods and dishes developed after the Columbian exchange

Ingredients

Multiple ingredients are also produced from maize, including corn syrup, corn meal, corn flour, corn oil, and corn starch.

Nutritional value

In prehistoric times Mesoamerican women used a metate to process dried maize into ground cornmeal, allowing the preparation of foods that were more calorie dense than popcorn. After ceramic vessels were invented the Olmec people began to cook maize together with beans, improving the nutritional value of the staple meal. Although maize naturally contains niacin, an important nutrient, it was not bioavailable without the process of nixtamalization. The Maya used nixtamal meal to make varieties of porridges and tamales. The process was later used in the cuisine of the American South to prepare corn for grits and hominy. ^{citation needed}

In a 100- gram serving, corn provides 86 calories and is a good source (10–19% of the Daily Value) of the B vitamins, thiamin, niacin (but see Pellagra warning below), pantothenic acid (B5) and folate (right table for raw, uncooked kernels, USDA Nutrient Database). In moderate amounts, they also supply dietary fiber and the essential minerals, magnesium and phosphorus whereas other nutrients are in low amounts (table).^{[ citation needed]}

Maize has suboptimal amounts of the essential amino acids tryptophan and lysine, which accounts for its lower status as a protein source. ^[12] However, the proteins of beans and legumes complement those of maize. ^[12]

Hazards

Pellagra

When maize was first introduced into farming systems other than those used by traditional native-American peoples, it was generally welcomed with enthusiasm for its productivity. However, a widespread problem of malnutrition soon arose wherever maize was introduced as a staple food. This was a mystery, since these types of malnutrition were not normally seen among the indigenous Americans, for whom maize was the principal staple food. ^[13]

It was eventually discovered that the indigenous Americans had learned to soak maize in alkali — water (the process now known as nixtamalization) — made with ashes and lime ( calcium oxide) since at least 1200–1500 BC by Mesoamericans. They did this to liberate the corn hulls, but (unbeknownst to natives or colonists) it coincidentally liberates the B-vitamin niacin, the lack of which was the underlying cause of the condition known as pellagra. ^[14]

Maize was introduced into the diet of non-indigenous Americans without the necessary cultural knowledge acquired over thousands of years in the Americas. In the late 19th century, pellagra reached epidemic proportions in parts of the southern US, as medical researchers debated two theories for its origin: the deficiency theory (which was eventually shown to be true) said that pellagra was due to a deficiency of some nutrient, and the germ theory said that pellagra was caused by a germ transmitted by stable flies. A third theory, promoted by the eugenicist Charles Davenport, held that people only contracted pellagra if they were susceptible to it due to certain "constitutional, inheritable" traits of the affected individual. ^[15]

Once alkali processing and dietary variety were understood and applied, pellagra disappeared in the developed world. The development of high lysine maize and the promotion of a more balanced diet have also contributed to its demise. Pellagra still exists today in food-poor areas and refugee camps where people survive on donated maize. ^[16]

Allergy

Maize contains lipid transfer protein, an indigestible protein that survives cooking. This protein has been linked to a rare and understudied allergy to maize in humans. ^[17] The allergic reaction can cause skin rash, swelling or itching of mucous membranes, diarrhea, vomiting, asthma and, in severe cases, anaphylaxis. It is unclear how common this allergy is in the general population.^{[ citation needed]}

The Z. mays plant has an OPALS allergy scale rating of 5 out of 10, indicating moderate potential to cause allergic reactions, exacerbated by over-use of the same plant throughout a garden. Corn pollen is heavy, large, and usually airborne in the early morning. ^[18]

Mycotoxins

Fungicide application does not reduce fungal growth or mycotoxin dramatically, although it can be a part of a successful reduction strategy. Among the most common toxins are those produced by Aspergillus and Fusarium spp. The most common toxins are aflatoxins, fumonisins, zearalenone, and ochratoxin A. Bt maize discourages insect vectors and by so doing it dramatically reduces concentrations of fumonisins, significantly reduces aflatoxins, but only mildly reduces others. ^[19]

See also

• Fodder
• Stover

References