Global Corn Production: Origins, Cultivation, and U.S. Dominance

Corn (Zea mays L.), known as maize in Europe and other regions, originated in the western hemisphere. It was first cultivated by indigenous peoples in southern Mexico approximately 9,000 years ago from a wild grass called teosinte. This ancient crop was vital to the growth of Mesoamerican civilizations, serving as a primary food source and becoming a central element of their cultures and traditions.

The United States is the leading global producer of corn, contributing over half of the world's total production. Most of this corn is cultivated in the Corn Belt, which includes states such as Iowa, Illinois, Nebraska, and Minnesota. This region is known for its rich soil and favorable climate, which are ideal for extensive corn farming. The Corn Belt is so productive that it generates more than 75% of the corn produced in the U.S.

Corn is a type of cereal grain, a grass that yields edible seeds or kernels. These kernels are consumed by both humans and animals, making corn a highly versatile and essential crop. It is used in numerous forms, including fresh corn, cornmeal, corn syrup, and as a key component in animal feed. Its nutritional benefits and versatility have made it a staple in many cultures around the world.

Although corn is grown globally, the U.S. leads in field corn production, often matching the combined output of all other countries. This dominance results from advanced farming techniques, extensive research, and the development of high-yield hybrid varieties. The U.S. prominence in corn production highlights its significant role in both the national and global agricultural economy.
Global Corn Production: Origins, Cultivation, and U.S. Dominance

Major Cereal: Maize

Cereals have come to dominate human nutrition since the first farmers began to cultivate them before the dawn of history. Corn, rice, and wheat are each produced annually to the extent of 700–1000 million tons.

Maize (Zea mays L.) is one of the most important cereal grains grown worldwide in a wider range of environments because of its greater adaptability. Maize (also referred to as corn) has a variety of uses. Maize provide a great source of starch, vitamins, proteins and minerals. One hundred gram of fresh grain can give about 361 calories of energy, 9.4 g protein; 4.3g fat, 74.4g carbohydrate, 1.8g fibre; 1.3g ash, 10.6 per cent water, 140mg vitamins, 9mg calcium, 290mg, phosphorus and 2.5mg iron.

Maize belongs to the family Graminaceae. It is the third most important food crop in the world surpassed only by two other grains, wheat and rice. In the green state, maize can be parched, baked, roasted, boiled or steamed on the cob.

Maize grain is widely used for the production of corn starch, high fructose corn syrup, corn oil dextrose, corn flakes, gluten, grain cake, lactic acid and acetone which are used by various industries such as textile, foundry, fermentation and food industries.

Maize or corn flour has a very mild flavor. The flour is used for making breads and as a thickening agent in foods such as custards and jellies. Popcorn, high-fiber whole grains is kernels of certain maize that burst when heated, forming fluffy pieces that are eaten as a snack.

Maize is also widely used in animal feed and other various industrial application. The grain can be used as a forage, feed for livestock and also making silage after fermentation of corn stocks. It is extensively used as the major source of calories in animal feeding and feed formulation. The grain gives the highest conversion of dry substance to meat, milk and eggs compared to other cereal grains. Currently, there has been interest in using maize for the production of ethanol especially in the United States and China, a substitute for petroleum-based fuels.
Major Cereal: Maize

Aflatoxin in corn

Aflatoxin is a cancer-causing by-product of mold that contaminated corn during drought. Aflatoxins characterized as aflatoxin B1, B2, G1 and G2 are potent hepatotoxic and carcinogenic metabolites of Aspergillus flavus and A. parasiticus that grow on agricultural commodities.

Consequently, they are of great concern as food contaminants and are closely monitored in oily-seeded crops and dairy products.

Aflatoxin formation can occur while the product is in the field or after harvesting. Improper post-harvest treatment of the commodity, i.e. insufficient drying, improper storage conditions, etc., can result in increased levels of aflatoxins.

Contamination of aflatoxins in corn profusely happens at pre-harvest stage when heat and drought field conditions favor A. flavus colonization.

Corn is major ingredient of swine, poultry and cattle feed. Animal losses from aflatoxin in corn, causing mortality and subtle losses in weight gain and feed conversion have been costly.

Because aflatoxin is one of the most potent cancer-causing substances created in nature the Food and Drug Administration sets limits for the amount allowed in food as low as one-half part per billion in milk.
Aflatoxin in corn

Production of cornstarch

In producing cornstarch, the corn is inspected and cleaned, then place in vats, where it is steeped in warm water containing a small concentration of sulfur dioxide for about 40 hr, to begin breaking the starch and protein bonds.

The kernel swells to more than double the size and increases its moisture content from about 15% to 45%. The softened kernels are next run through an attrition mill to break up the kernels.

If not previously degerminated the steeped kernels are passed through mills that separate the germ and loosen the hull. The germ is removed by density separation in a cyclone.

The mass is then passed through tanks of water where the germs (being lighter) float and are skimmed off. The remaining endosperm, containing starch, corn gluten and hulls is then finely ground in steel mills.

The finely ground material is then passed through sifters to remove hulls, the starch and gluten passing through. The starch is separate from gluten by centrifugation. The starch-gluten suspension is concentrated by centrifugation and the higher and lower densities of gluten and starch facilitate centrifugal separation, again in a cyclone.

The gluten is dried and the starch is washed and dewatered. With hydrocyclones and a centrifuge the starch settles and separates from the water and fibers.

The starch fraction is finally dried to yield the familiar cornstarch. Cornstarch can be used as such in manufacture foods or be further converted into corn syrup by the hydrolytic action of acid or starch-splitting enzymes.
Production of cornstarch

Sitophilus zeamais Motsch

Family of Curculionidae, maize weevil (Sitophilus zeamais Motschulsky) is an important pest of maize in the tropics, particularly where grain is stored on-farm and without chemical protestants.

Pesticides for control of weevils are available, but the resource poor farmers of the developing world often cannot afford them. Sitophilus zeamais Motsch is virtually cosmopolitan throughout the warmer parts of the world, extending as far north as Joan and southern Europe.

Infestation often starts in the field, and is later carried into the grain stores; adults are winged and fly readily.

Eggs are deposited inside the grains, in small holes chewed by the female; each female may lay 300-400 eggs over a period of several weeks. The larvae remain inside the grains and pulpate when they reach a body length of about 4 mm.

The adults emerge through the characteristics small circular holes in the grains leaving a roughly circular hole approximately 1.5 mm in diameter, and are active insects, flying readily and often infecting ripe crops in the field.

The weevils use their elongated snouts, which have jaws for digging into the grain, while the females use their snouts for digging hole into which they lay eggs.
Sitophilus zeamais Motsch

Corn flour processing

Modern corn mills can produce a variety of grits, meals and flours. Corn milled for flour (corn meal) is cleaned, as is wheat the moistened to a water content of 21%. The germ is removed mechanically.

The endosperm is then dried to moisture content of 15% passed through crushing rolls, and sifted to remove the bran.

With the use of sieves, milled corn is separated into grits (largest-sized particles) and meals and flours (smallest sized particles). They are fried at 65 °C and cooled before packing. The flattened germs are used to produce corn oil.

Among many other industries, maize starch has its feet firmly placed in the high growth Indian food industry. Maize starch or corn starch or corn flour is avidly used in processed food industry majority in products like bakery, beverages and confectionery.
Corn flour processing

Protein content of corn

Corn has the lowest protein content of the cereals (7.1%) but a high starch content (65.7%) and a fiber content of 1.5%. It has the highest fat content of grains or legumes (4%).

The protein contend of corn is inversely related to starch content and grain yields. Bulk density is related to increased starch content when other factors are constant.

The amount of nitrogen in the soil, and when it is applied significantly affect protein content.

The development of hybrid strain has improved the yield of field corn, which is lower in protein than wheat, and like all vegetable protein, including wheat, corn is deficient in some amino acids and so does not provide a complete protein for humans.

Corn is especially deficient in the amino acid, but a variety of high-lysine corn has been developed that may eventually have a great impact on human nutrition on some parts of the world.
Protein content of corn

The Wet Milling of Corn

The corn wet milling process was developed in the early 19th century at which time alkali was used. This wet milling is a complex used for manufacturing of corn starch and the various sweeteners obtained from its hydrolysis.

The development of wet milling was based on the observation that a white, insoluble granular material settled to the bottom of the pan when quantities of cut tubers were washed.

As opposed to dry milling, which separates the anatomical parts of the corn kernel, wet milling separates the kernel components into their chemical constituents.

In the corn wet milling process, the use of SO2 is very important. It breaks down the protein matrix that surrounds the starch particles and increases starch yield during milling.

The wet milling process consist of cleaning the grain, an initial soaking in water to soften the kernels, milling to separate the components through screening, centrifuging and washing and finally, production of the end products: starches, sweeteners, proteins and co-products.

An enzymatic corn wet milling then has been developed that’s shows the potential to reduce or completely eliminate the use of SO2 and produce starch yields comparable to the conventional corn wet milling.

Wet milling creates a high-quality cornstarch slurry used in the production of syrup as well as in the manufacture of high quality dry starch.
The Wet Milling of Corn

The structure of corn

The corn kernel is not merely a seed but as one seeded fruit. The kernel consists of the pericarp or skin, germ or embryo and the endosperm.

Corn grain is composed of endosperm (82-83%), germ (10-11%), pericarp (5-6%) and tip cap (0.8-1.0%).

The pericarp is the outmost layer that is characterized by high crude fiber content, mainly consisting of hemicellulose, cellulose and lignin. The pericarp protects the kernel and resists penetration by water. Endosperm contains approximately 87-88% of starch that consists of amylose and amylopectin.

The endosperm consists of a thin layer of aleurone cells containing oil an protein and a large inner portion of storage tissues containing starch and protein.

The germ is high in oil, protein, sugars, vitamins and minerals with little starch.

The aleurone is a single layer of cells in the pericarp that contain a larger proportion of oil, protein, minerals, ash, vitamins and enzymes that other cells.
The structure of corn

The early history of corn

Corn (Zea mays L.) is native to the Americas and is their most important cereal crop. Corn originated in Mexico, evolving form the wild grass Teosinte (Zea mays sp. mexicana).

The first people to grow corn were Native Americans living in Mexico’s valley of Tehuacan about6,000 years ago.

Corn becomes symbol of religion and prosperity in The Mayan civilization. From this center corn spread northward to Canada and southward to Argentina.

Christopher Columbus, the European explorer who discovered America, found corn on his trip to the new world in 1492. The corn known to the native as “mahyz.”

Corn is still universally known as maize from the early Spanish translation. Maize was not popular known as corn until the American colonists applied this British term for grain.

Columbus brought corn back to Europe. Portuguese sailors then carried corn to China in 1516. Soon the plant spread by trade to Africa.

Corn played an important role in the colonization and settling of United States. The native Americans taught the colonists how to convert the grain into food and livestock feed.

Bread made from corn quickly became staple foods in the American colonies and other foods, such as mush, porridge and breakfast grits, were important to pioneers migrating west.
The early history of corn

What is corn?

Corn (Zea mays L.) or maize, as it is known in Europe and other part of the world originated in the western hemisphere.

The United States produces more than half of the corn grown in the world, and more than three-fourth of this corn is grown in the region known as the Corn Belt.

Corn is a cereal, a type of grass that produces a grain people and animal eat.

Although it is now grown around the world, production of field corn in the United States exceeds in any other country and is usually about equal to that of the rest of the world put together.

Many people in North America eat corn on the cob, and heat corn kernels to make popcorn, but most corn is used to make thousands of different product.

Field corn is entirely different as a food crop from the sweet corn that is harvested immature in summer and cooked fresh on the cob or cut from the cob in food plants and preserved by canning or freezing later consumer us as a vegetable.

A very small part of the field corn crops of white corn varieties used for making the hominy grits while corn meal sold at retail, the grits being use as vegetable menu item or hot breakfast cereal, and the meal for making white corn bread and muffin.

However, since corn is grown primarily for animal feed, for which the yellow varieties are preferred, availability and economics dictated that yellow corn must be the grain of choice for most food ingredient uses, including breakfast cereal.

Milling of cereals is an ancient art, The objective is to make cereals more palatable or to isolate attempts to remove the bran fractions.

Corn flour is produced either by wet milling or dry milling methods. In wet milling, corn is cleaned from broken kernels. chaff and other impurities an steeped in warm water. The steeped slurry is removed and the corn is ground in a ‘degerminating’ mill.

In dry milling, cleaned corn is passed through a steaming conveyor, which toughens the hull and facilities its removal by subsequent grinding.
What is corn?