The corn is a grain native of America, used sometimes as a vegetable. Although it is part of the traditional indigenous diet throughout the American continent, it is less popular in Europe where it is more reserved for livestock. We mostly know yellow corn, but in recent years we have started to see on the shelves products made of “blue” or “purple” corn. Very versatile, corn comes in a thousand and one forms: it can be eaten directly on the cob, frozen, canned or puffed. We also know its derivatives such as flour, semolina, oil, bran, starch and corn syrup, which can be found in a multitude of foods, from breakfast to dessert.

Active ingredients and properties

For grain products in general

Cereal products are of great importance in our diet. One of Health Canada’s Food Recommendations for the Health of Canadians is to give “the largest share of grains, breads and other grain products, and vegetables and fruit” ¹ . The Canada Food Guide to Healthy Eating recognizes this recommendation and emphasizes the choice of grain products whole grain or enriched ² . The American authorities, for their part, recommend that at least half of the cereal products consumed be whole grain ³ .

These recommendations are based on the results of epidemiological studies which demonstrate that the consumption of whole grains is linked to a lower risk of cardiovascular disease and diabetes ⁴ , certain cancers ^{5 , 6} and obesity ^{7 , 8} . These beneficial effects are said to be linked to the synergy between the many compounds found in whole grain products, such as fiber, antioxidants, vitamins and minerals. As the majority of these compounds are contained in bran and germ ⁹ , cereals benefit from being consumed as unrefined as possible.

For corn

Antioxidants . Antioxidants are compounds that protect the cells of the body from damage caused by free radicals . These are very reactive molecules which are said to be involved in the development of cardiovascular diseases , certain cancers and other diseases linked to aging ¹⁰ . A study comparing the antioxidant activity of four cereal grains (corn, wheat, oats, rice) showed that corn was the one with the highest activity ¹¹ . Other researchers have observed that the total antioxidant activity of corn increases when it is cooked ¹², probably as a result of the release of certain antioxidant compounds under the effect of heat.

• Phenolic compounds . Corn contains antioxidant phenolic acids, one of the main ones being ferulic acid ¹³  : corn bran is one of the foods that contain the most ¹⁴ . However, it has been observed in animals that only a very small proportion of the phenolic acids in corn bran are absorbed by the digestive system. However, these researchers believe that various treatments, for example heat, could make these phenolic acids more accessible to the body, and thus improve their bioavailability. ¹⁴. Other researchers have discovered in purple corn a derivative of quercetin, another type of phenolic compound, which has demonstrated strong antimutagenic potential in vitro ¹⁵ . It is not known, however, whether these effects can also apply to humans.
• Lutein and zeaxanthin . Corn contains lutein and zeaxanthin, two antioxidant compounds in the carotenoid family ¹⁶ . According to Health Canada’s Canadian Nutrient File , an ear of corn contains 745 μg of lutein and zeaxanthin. For comparison, 250 ml (1 cup) of raw spinach, a vegetable very rich in lutein and zeaxanthin, contains 3,867 μg. In addition, researchers have observed that cooking corn makes these two compounds more bioavailable, that is to say more apt to be well absorbed by the body ¹⁷ . Lutein and zeaxanthin accumulate in the macula and retina of the eye ^{16 , 18}, thus protecting it from oxidative stress which could cause it damage. Moreover, data from a review of the scientific literature indicate that a regular intake of lutein and zeaxanthin is associated with a lower risk of macular degeneration and cataracts ¹⁶ , two eye diseases. In addition, we are beginning to believe that these compounds could help prevent certain cancers, especially those of the breast and lung and contribute to the prevention of cardiovascular diseases ¹⁶ . Note, however, that studies on the cardiovascular level are still limited and sometimes contradictory.
• Anthocyanins ( blue or purple corn ). Anthocyanins, antioxidant pigments such as cyanidine and pelargonidine, are responsible for the particular color of certain varieties of corn ¹⁹ . The anthocyanins of purple corn have demonstrated antimutagenic properties in vitro ¹⁵ . In animals, the consumption of anthocyanins from purple corn has provided some protection against colon cancer ²⁰ and has made it possible to counteract the harmful effects of a diet rich in fat (for example: suppression of the accumulation of tissue fats and normalization of blood sugar) ²¹. However, more studies are needed to verify whether these properties can also be observed in humans.
• Tocopherols ( corn oil ). Corn oil contains antioxidants belonging to the tocopherol family (vitamin E). It is particularly rich in one of these compounds called gamma-tocopherol ²² . It has been shown in humans that the blood concentration of gamma-tocopherol increases when corn oil is added to the usual diet ²² , and that the tocopherols of corn oil have antioxidant activity in human organism ²³ . Another clinical study in humans has shown that corn oil, through gamma-tocopherol, provides protection against DNA damage in certain blood cells ²⁴, an aspect which could be favorable for the prevention of cancer .

Cardiovascular diseases . Some studies have looked at the potential effects of corn-derived foods on cardiovascular health.

• Corn oil . In a human study, adding corn oil to a normal, balanced diet led to a decrease in blood LDL cholesterol (“bad” cholesterol). Researchers indicate that this effect could be attributed to several compounds. They mention in particular polyunsaturated fats , which are the main fats present in corn oil. The phytosterols may also contribute to these benefits: these are compounds related to cholesterol, but promising to health. Corn oil is one of the best sources ²⁵ . In addition, another clinical study in humans has shown that the phytosterols in corn oil are the main compounds responsible fordecreased absorption of cholesterol by the body ²⁶ .
• Corn bran . A study in hypercholesterolemic men (too high blood cholesterol) found that adding finely ground corn bran to a low-fat diet had more effect on lowering blood cholesterol than the low-fat diet alone ²⁷ . However, these researchers were unable to explain by what mechanism corn bran exerted this benefit.

Other properties

Most important nutrients

See the meaning of the nutrient source classification symbols

Phosphorus . Sweet corn is a source of phosphorus (see our fact sheet on Phosphorus nutrients ). Phosphorus is the second most abundant mineral in the body after calcium. It plays an essential role in the formation and maintenance of healthy bones and teeth. In addition, it participates in the growth and regeneration of tissues and helps to maintain normal blood pH . Finally, phosphorus is one of the constituents of cell membranes.

 Magnesium . Sweet corn is a source of magnesium. Magnesium participates in bone development, protein construction, enzymatic actions, muscle contraction, dental health and the functioning of the immune system. It also plays a role in energy metabolism and in the transmission of nerve impulses.

 Iron . Sweet corn is a source of iron for humans. Each body cell contains iron. This mineral is essential for the transport of oxygen and the formation of red blood cells in the blood. It also plays a role in the production of new cells, hormones and neurotransmitters (messengers in nerve impulses). It should be noted that the iron contained in food of vegetable origin is less absorbed by the organism than the iron contained in food of animal origin. However, the absorption of iron from plants is favored when consumed with certain nutrients, such as vitamin C.

 Zinc . Canned sweet corn is a source of zinc for women. Zinc is involved in particular in immune reactions, in the production of genetic material, in the perception of taste, in the healing of wounds and in the development of the fetus. It also interacts with sex and thyroid hormones. In the pancreas, it participates in the synthesis (production), the storage and the release of insulin.

 Manganese . Sweet boiled and drained corn is a source of manganese. Manganese acts as a cofactor for several enzymes that facilitate a dozen different metabolic processes. It also participates in the prevention of damage caused by free radicals .

 Copper . Canned sweet corn is a source of copper. As a constituent of several enzymes, copper is necessary for the formation of hemoglobin and collagen (protein used for the structure and repair of tissues) in the body. Several copper-containing enzymes also help the body’s defense against free radicals.

 Vitamin B1 . Sweet boiled and drained corn is a source of vitamin B1. Also called thiamine, vitamin B1 is part of a coenzyme necessary for the production of energy mainly from the carbohydrates that we eat. It also participates in the transmission of nerve impulses and promotes normal growth.

 Vitamin B2 . Canned sweet corn is a source of vitamin B2 while boiled and drained sweet corn is a source for women only. This vitamin is also known as riboflavin. Like vitamin B1, it plays a role in the energy metabolism of all cells. In addition, it contributes to tissue growth and repair, hormone production and the formation of red blood cells. Vitamin B3 . Sweet corn is a source of vitamin B3. Also called niacin, vitamin B3 participates in many metabolic reactions and contributes particularly to the production of energy from the carbohydrates, lipids, proteins and alcohol that we ingest. It also collaborates in the DNA formation process, allowing normal growth and development.

 Pantothenic acid . Sweet corn is a source of pantothenic acid. Also called vitamin B5, pantothenic acid is part of a key coenzyme that allows us to adequately use the energy present in the food we eat. It also participates in several stages of the synthesis (production) of steroid hormones, neurotransmitters (messengers in nerve impulses) and hemoglobin.

 Folate . Sweet corn is a source of folate. Folate (vitamin B9) is involved in the production of all cells in the body, including red blood cells. This vitamin plays an essential role in the production of genetic material (DNA, RNA), in the functioning of the nervous system and the immune system, as well as in the healing of wounds and wounds. As it is necessary for the production of new cells, adequate consumption is essential during periods of growth and for the development of the fetus.

 Vitamin C . Sweet corn is a source of vitamin C. The role that vitamin C plays in the body goes beyond its antioxidant properties; it also contributes to the health of bones, cartilage, teeth and gums. In addition, it protects against infections, promotes the absorption of iron from plants and accelerates healing.

Source  : Health Canada. Canadian Nutrient File , 2005.

Compounds that are both harmful and beneficial in cereals
Cereal grains contain phytochemicals such as phytic acid, one of the most abundant microconstituents in grain. Corn contains more phytic acid than rice or wheat ²⁸. This compound, which is found in greater quantity in the outer envelope of the grain (bran) and the germ, has the ability to bind to certain minerals (calcium, magnesium, iron, zinc) and thus reduce their absorption in the intestine. However, researchers agree that, in a North American context where there is an abundance and diversity of food and where nutritional deficiency is rather rare, this effect has little impact on health. In addition, certain domestic processes (for example soaking in water, cooking) make it possible to remove part of the phytic acid from maize ^29-31 , which makes the minerals more absorbable. The consumption of phytic acid (or phytate) would even have a beneficial side since it acts as an antioxidantin the body. The potential benefits of phytic acid have not yet been validated in humans, having been observed only in animals and in vitro.

Corn is native to Mesoamerica (Mexico, Guatemala). It would have been domesticated a few millennia before our era, possibly in two distinct places, either in Mexico and in the highlands of Peru, where very different types from one another appeared and evolved, which explains why there is such variety in modern forms. Much speculation was made about his wild ancestor, which has never been found in the wild, until an American geneticist announced in 2004 that he was probably born from a spontaneous cross between two plants. very close, the teosinte, considered until then as the most plausible candidate, and another grass belonging to the genus Tripsacum .

Maize did not reach North America until much later, approximately 1,000 years before our era, but it would then be adopted by all Amerindian peoples. When Jacques Cartier landed in the Gaspé Peninsula and the St. Lawrence Valley in the XVI ^th  century, he notes that the Hurons and Iroquois cultivate at least one variety, and when it upriver to Hochelaga (now Montreal ), he sees “large and beautiful fields” of corn.

While the Amerindians of the south and the north devote him, without exception, an almost religious cult and consider him as the Mother of all food, the Spanish conquerors will not be interested in it and will content themselves with giving it to farm animals , preferring to grow wheat, which they brought in their luggage. This bad reputation will follow him in his journeys through Europe where he will not be popular in human food, with the exception of northern Italy, the Basque Country and certain regions of central Europe which l ‘will gladly adopt.

By cons, in Africa, where the Portuguese will introduce it, it will become a staple, supplanting the XX ^th  century sorghum and millet, and, to a lesser extent, tubers and roots which were hitherto essentially of food. Under the British Empire, it would be the main food for black miners and, in the United States, for slaves brought back from Africa. It will also play an important role in the diet of Indonesians and people in some remote regions of China, where rice grows poorly.

Of the three most important cereals on the globe (wheat, rice, corn), it is the only one not to be cultivated essentially to feed human beings. Only a fifth of world production is intended for them, while two thirds go to feed animals and about a tenth to the manufacture of industrial products: plastic, ethanol, oil derived from germ, starch, sweeteners (syrup, fructose, dextrose , etc.), pharmaceuticals (vitamins C and E, amino acids, organic acids, antibiotics), etc.

The genus Zea includes only a few species, of which Zea mays is the most important. Thousands of varieties have been selected for this species, which are grouped into three categories according to the use for which they are intended, namely: grain corn , cultivated essentially as fodder and silage intended for animal feed and incidentally for production flour and semolina intended for human consumption; the sweet corn and corn blowing , especially consumed in the United States and Canada.

Choose well

Corn on the cob (sweet corn)  : it is offered on North American markets throughout the summer. Although after harvesting its sugar is transformed less into starch than that of grain corn, it still loses its taste qualities over time. It is therefore recommended to buy it as fresh as possible, preferably directly from the producer or at the market, and to consume it immediately. The leaves should be green and smooth, and the grains curved.

Grain corn: it is generally found in the form of flour, flakes, oatmeal and semolina, which unfortunately have undergone a transformation process intended to remove bran and germ in order to increase their shelf life. A few rare flour mills offer whole grain products; make sure they are freshly prepared, at the risk of being rancid. Some companies also sell whole, unprocessed grain.

Tortillas: Commercial products are generally made from white grain corn flour or wheat flour, although we are starting to find products made from yellow, red or blue grains. Preferably buy refrigerated or frozen products, which contain less preservatives.

GMOs

A large part of the “Mexican” products ( tortillas , tacos and chips) that are found on the shelves of our grocery stores are made with corn flour from grains of genetically modified varieties. Note that these products do not come from Mexico, a country that does not grow any variety of genetically modified corn, but rather from the United States, the world’s largest producer of GM plants.

Corn starch, dextrose and maltose products are also mostly made with GMO corn, although there will not necessarily be traces of it in the food products containing it, as these are purified substances.

Morning cereals made from corn flakes can be made with transgenic corn.

In Canada, the cultivation of genetically modified fresh corn is not authorized, while it is in the United States.

Culinary dishes

Dried grains and their derivatives

They are the basis of many South American dishes:

• The pozole , thick soup boiled composed of whole grains (if possible, use of colored speckles). Cook the grains for four hours with roasted hot peppers, garlic, onion, tomatoes and, if desired, a small boneless pork roast. Add oregano and cilantro leaves and cook for another hour.
• The masa , paste made of boiled beans, then coarsely crushed, ground or just more or less finely with water. This dough is the basis of various culinary preparations, the most common being tamales and tortillas .
• Tamales  : these small packets of corn dough wrapped in the spathes (the leaves surrounding the ear) or the stem leaves and cooked in steam or in the oven formed the basis of the diet before the invention of tortillas . Depending on the recipe, in addition to the corn dough, the tamales can be stuffed with beans, meat, hot sauce or fruit.
• Tortillas  : serve as is, with the meal, or stuffed with various ingredients (red or black beans, lettuce chiffonade, grated cheese, salsa, guacamole, etc.) and then fried or topped with sauce and baked. Many Mexican and South American specialties are prepared with these universal patties.
• We also prepare a soup, the sopa de tortilla  : sauté a few minutes of hot pepper, tomatoes, onions, garlic and epioxide (you will find them in Mexican grocery stores) in very oil hot. Pass this preparation in the blender, then put it to cook in a saucepan with chicken or vegetable broth. Bring to a boil, season with salt and pepper. To serve, place in the bowl of each guest pieces of avocado, grated cheese and tortilla strips that have been fried or baked, and pour the soup. Garnish with lime wedges, the juice of which will serve to flavor the dish.

In Italy, corn is eaten in the form of polenta (semolina): cook it in boiling and salted water for about five minutes without stopping brewing to prevent the preparation from sticking to sides of the pan. Add a little butter and serve as is or with a tomato sauce.

Other suggestions of polenta  :

• Put it in a baking dish and cover it with the cheese of your choice and spend a few minutes under the grill.
• Add to it, at the end of cooking, grated Parmesan cheese and bouquets of broccoli or broccoli raab (rapini) previously steamed.
• Once cooled, it will thicken further. We can then cut it into thick slices to serve cold with a salad, soup, etc.

In the Basque Country , we prepare the meture , a kind of porridge made of cornmeal, eggs and milk, seasoned with nutmeg, salt and pepper, and baked. You can incorporate slices of smoked ham, cheese or jam.

In Egypt , a flat bread is made with corn flour with 5% ground fenugreek seeds, which, it is said, helps to increase the protein content (fenugreek is a legume), the digestibility and storage. In addition, a sour ferment (yogurt or whey) is added to the dough, which is left to rise overnight.

Flour and semolina can be incorporated into cake, bread, muffin, pancake, waffle, cookie , etc. preparations .

Fresh cor

• On the cob , simply boiled in water, baked in its leaves or roasted on the grill. In place of the butter, you can season it with a drizzle of oil and lemon, salt, pepper and fine herbs (thyme, paprika, chives, lemon balm and chervil go particularly well with him and marry very well together).
• In soups or chowder . Collect the grains with a knife after placing the ear upright on the work surface. Cook them with milk, diced potatoes and minced onions. Garnish with chopped parsley. Or prepare a Native American sagamite, by cooking the grains with game, poultry and fish, as well as seasonal vegetables (carrots, cabbage, turnip, onion). Thicken with flour. We can omit the meat.
• In the Native American succotash . The grains are cooked with lima beans, onion, a little salt and sugar. You can replace lima beans with peas or snap beans cut into rings.
• We will make a pleasant summer stew by marrying young ears cut into sections (with the core), zucchini or patisson, new potatoes, tomatoes, tender carrots, small eggplant, red pepper, green beans, garlic and onion, that first, fry in oil before wetting them with water or broth. Season with the herbs of your choice.
• In the shepherd’s pie. You can vary endlessly this typically North American dish made up of superimposed layers of ground meat, corn and mashed potatoes. Use red or blue potatoes, or replace some of the mashed potatoes with mashed squash or pumpkin, and the ground meat with lentils or another small bean legume.

• In the pancakes. Chop the grains and mix them with eggs and a little flour.
• In the uchepos . Stuff the husks of young cobs (or cabbage leaves) with coarsely corned grains and salted. Steam about 45 minutes. When ready to serve, open the leaves and serve the stuffing with sour cream and a sauce made up of tomatoes, tomatillos, jalapeno peppers, garlic and onion, browned in oil and cooked for about twenty minutes.
• In Asian cuisine. Small immature ears are often sautéed with snow peas, bamboo shoots, Chinese cabbage or other seasonal vegetables. We finish cooking by adding chicken broth, soy sauce and oyster sauce.

Corn “milk”

By passing the sweet corn kernels through the extractor or by pressing them in a cloth, the milk that escapes can be collected. Cooked over low heat, it will thicken and can be used in various preparations: custards, soufflés, sauces, or simply seasoned with vanilla or herbs, chilled and eaten as a snack.

By choosing varieties that ripen at different times (early, semi-early and late) and by sowing successively until July, we will be able to harvest fresh corn throughout the season. Serious hobbyists who want to grow or pop grain corn should be sure to isolate these types from fresh corn varieties, at the risk of changing the sugar content of the latter. Sow these varieties as early in the season as possible because the grain takes a long time to mature. To germinate, corn requires temperatures above 13 ° C. We will not sow it before June in southern Quebec.

It is a demanding plant in fertilizer. Bury manure or compost the previous fall or cultivate it after a legume.

To favor pollination and obtain well-supplied ears of grain, it is best to sow in blocks of four short rows rather than on a single row. Space the seeds 22 cm to 30 cm in the row and the rows from 70 cm to 85 cm.

Irrigation: water in the event of drought, particularly at the time of the emergence of the ears and silks, and the maturation of the ears.

Insect control: you can exercise some control over the European moth by spraying a solution of Bt ( Bacillus thurigensis ).

The small immature ears are picked just a few days after the formation of the bristles, the fresh, but not mature, ears about 20 days later, when the tips of the bristles begin to brown and dry.

The larvae of two insects, the European moth and the root beetle, cause corn producers hundreds of millions of dollars in losses each year. This is why, over the past ten years, the areas devoted to transgenic corn, which has resistance to these two insects, have increased considerably in North and South America.

However, transgenesis remains a controversial technique within the scientific community and some researchers prefer to explore the classic paths of selection and crossing, which do not use genes from organisms foreign to the plant. An American geneticist has recently created hybrid varieties showing an amazing resistance to these two insects, as well as to the tomato moth, which also attacks corn. It was by crossing corn with Tripsacum, one of her wild ancestors, that she obtained these varieties.

According to this researcher, only a better knowledge of the genetics of corn and the traditional uses that people have made of it in the past will allow to generate sustainable modern agricultural applications. For this, it is necessary to preserve the genetic capital of maize, because in the old varieties there may be the solution to current and future problems. However, this capital is currently under threat due to the exponential increase in genetically modified corn crops, which risk contaminating old varieties of corn and teosinte. The threat also comes from the current economic expansion, which pushes the Mexican peasants to desert their farms or to turn to commercial agriculture and to abandon the varieties which they sowed for generations.

To counter this threat, the International Center for the Improvement of Maize and Wheat (CIMMYT) has implemented an extensive program to preserve the diversity of corn. This program is based on close collaboration between scientists and farmers, the latter being the holders of ancestral knowledge which very often escapes the former.