Corn or Maize (Zea mays L.) as it is also known belongs to the family Poaceae.  Corn is the leading cereal crop in the world followed by rice and wheat (1). Corn is used as a staple food in many areas such as Latin America, Africa and Asia (2, 3). Corn is also called by other names such as zea, silk maize, makka, barajovar.

Corn grain is comprised of endosperm (82-84%), germ (10-12%) and bran (5 -6%) (2). Corn is a cereal grain which is processed using wet or dry milling to produce a variety of food products such as starch, oil, grits, meal, flour, and bran. Several foods such as breakfast cereals, tortillas, rotis, snacks etc are made from these corn products (2). Sweet corn is used as a vegetable and is very popular. It is also available in frozen and canned form (4).

Nutritive value of corn grain

Corn is a source of all the macronutrients

The major portion of corn grain is made up of carbohydrate that is about 74 % like any other cereal grain (5). This includes about 10 % dietary fiber and the rest is starch (2). Corn also provides about 5 % of fat and 9 % of protein. Corn germ contains 45 to 50 % oil (3). Corn is a source of all the three macronutrients and is an important source of energy as it supplies 365 kcals per 100 grams.

Though corn is a fair source of protein, like any other cereal protein it does not contain all the essential amino acids, therefore it is not a complete protein.

Micronutrients in corn

Corn is also a good source of certain micronutrients like magnesium, potassium, phosphorous and selenium.  It is a fair source of iron and zinc. The sweet corn variety is a fair source of B vitamins (5).

Health benefits of corn

Corn is a good source of dietary fiber and also resistant starch. Like dietary fiber resistant starch also is not digested. Both of these components have beneficial effects on gut health and are good for those who have diabetes.

Resistant starch has glucose reducing effect and also has a beneficial effect on insulin response. Dietary fiber has several health promoting effects. It contributes towards weight loss, managing blood glucose and lipid levels. Dietary fiber is also good for gut health.

Potassium is an essential mineral and it performs several important functions in the body. Potassium has a protective effect on heart health because potassium lowers blood pressure (6). Corn provides 287 mg of potassium per 100 grams which is a considerable amount.

Phytochemicals in corn

Plant based foods exert certain health benefits that are attributed to the presence of fiber and to a variety of plant-derived constituents known as phytonutrients and phytochemicals. The term “Phyto” means plant in Greek. They exert their health beneficial potential by different mechanisms such as antioxidant, enzyme-inducing and enzyme-inhibiting effects (7).

Phytonutrients are the plant chemicals with specific biological activities, hence are also called bioactive components that support human health. It is said that when there are more phytochemicals in the diet consumed, they help in reducing the risk of development of chronic diseases such as type 2 diabetes and cardiovascular diseases (3).

Corn is a decent source of phytochemicals such as phenolic acids, carotenoids, flavonoids (anthocyanins) and dietary fiber. Phenolic acids present in corn are ferulic acid, coumaric acid, and syringic acid (4).

Carotenoids are found more in yellow and red corn whereas anthocyanins are more in red, blue, purple and black corn. Phytosterols or plant sterols are concentrated more in the kernel (4).

Antioxidant activity in corn is much higher when compared to other cereals such as rice, wheat and oats. The antioxidant activity of corn is attributed to the phenolic acids, anthocyanins and the carotenoids present in corn (4).

Corn oil is a rich source of phytosterols which are known to have cholesterol lowering effect. The major phytosterol present in corn oil is sitosterol which accounts for almost three fourth of the total phytosterol content. The rest of the phytosterol present is in the form of campestanol (4).

Final word

Corn is a source of all the three macronutrients that is carbohydrate, fat and protein. It can be a major source of energy when included in the diet. Corn which is a good source of resistant starch, dietary fiber and phytochemicals such as carotenoids, phenolic acids and flavonoids when consumed as part of a balanced meal would provide nutrients as well as health benefits because of the bioactive phytochemicals.

References

1. 2014. Food and agriculture organization of the United Nations.

http://faostat.fao.org/site/567/default.aspx#an

2. Ai, Y. and Jane, J. L. (2016) Macronutrients in corn and human nutrition, Comprehensive Reviews in Food Science and Food Safety. Vol. 15(3).

https://onlinelibrary.wiley.com/doi/full/10.1111/1541-4337.12192

3. Shah, T.R., Prasad, K., Kumar, P. and Yildiz, F. (2016)Maize—A potential source of human nutrition and health: A review, Cogent Food & Agriculture. Vol. 2(1).

https://www.tandfonline.com/doi/full/10.1080/23311932.2016.1166995

4. Siyuan, S., Tong, L. and Liu, R. (2018) Corn phytochemicals and their health benefits, Food Science and Human Wellness. Vol. 7(3).

http://www.sciencedirect.com/science/article/pii/S2213453018301009

5. National Nutrient Database for Standard Reference Legacy Release, United States Department of Agriculture. Basic Report:  168920, Corn grain.

https://ndb.nal.usda.gov/ndb/search/list

6. Lanham-New, S.A., Lambert, H. and Frassetto, L. (2012) Potassium, Advances in Nutrition. Vol. 3(6).

https://academic.oup.com/advances/article/3/6/820/4644562

7. Bender, A. E. (2005) Fruits and Vegetables. In: Caballero, B., Allen, L. and Prentice, A. (eds). Encyclopaedia of Human Nutrition. Elsevier Academic Press. Pp 356-366.