NUTRITIONAL IMPORTANCE AND HEALTH BENEFITS OF MAIZE

Introduction:

Maize or Indian corn (called corn in some countries) is Zea mays, a member of the grass family Poaceae. Zea is an ancient Greek word which means “sustaining life” and Mays is a word from Taino language meaning “life giver.” The word “maize” is from the Spanish connotation “maiz” which is the best way of describing the plant. It is a cereal grain which was first grown by people in ancient Central America. Approximately 1 billion tonnes are harvested every year. Due to its highest yield potential among the cereals it is known globally as “Queen of cereals”. Maize is generally used for animal feed. It is widely processed into various types of products such as cornmeal, grits, starch, flour, tortillas, snacks, and breakfast cereals. Maize flour is used to make chapatis or flat breads. Most is used to make corn ethanol, animal feed and other maize products, such as corn starch and corn syrup.

Maize is a leafy stalk whose kernels have seeds inside. It is an angiosperm, which means that its seeds are enclosed inside a fruit or shell. It is a source of nutrition as well as phytochemicals compounds.

Taxonomical classification:

Kingdom: Plantae
Subkingdom: Tracheobionta
Division: Magnoliophyta
Class: Liliopsida
Subclass: Commelinidae
Order: Cyperales
Family: Poaceae
Genus: Zea
Species: Zea mays
The number of chromosomes in Zea mays is 2n = 20.

Nutritional value:

Maize grain contains 70% carbohydrates, 10% protein, 10.4% albuminoides, 4% fat, 2.3% crude fiber, 1.4% ash. Starch is the major nutritional component of maize kernel constituting about 70 % of its weight. Starch composition in maize is genetically controlled, and significant variation has been observed in the amylose to amylopectin ratio which makes it suitable for different industrial purposes. Maize is also a source of oil which is highly regarded for human consumption as it reduces the blood cholesterol concentration. Many value-added products as well as fermented foods have been produced from maize which is consumed in different forms worldwide. Naturally, maize is a rich source of carotenoids such as beta-carotene, zeaxanthin, lutein and cryptoxanthin which have highly diverse health benefits ranging from maintaining normal vision to lowering of oxidative stress.

It also contains vitamin C, vitamin E, vitamin K, vitamin B1 (thiamine), vitamin B2 (niacin), vitamin B3 (riboflavin), vitamin B5 (pantothenic acid), vitamin B6 (pyridoxine), folic acid, selenium, N-p-coumaryl tryptamine, and N-ferrulyl tryptamine. Potassium is a major nutrient present which has a good significance because an average human diet is deficient in it (Kumar & Jhariya, 2013). Its high dietary fiber content ensures that it plays a significant role in the prevention of digestive ailments like constipation. The antioxidants present in it also act as anti-carcinogenic agents and help in preventing Alzheimer’s disease.

Generally, maize contains zein protein which is deficit of lysine and tryptophan amino acids. However, Quality protein maize (QPM) contains more than double these amino acids more than double than general maize. Moreover, the digestibility of protein is higher in QPM.

According to the USDA National Nutrient Database, corn not only provides the necessary calories for healthy, daily metabolism but is also a rich source of vitamins A, B, E, K, and many minerals. The major nutrients available when 100gm of corn is served are listed below:

Product diversification of maize: Major products of maize that are consumed are: bread (roti), puddling (dhindo or aanto), boiled green, roasted green, roasted dry, pop corn, sweet corn soup, baby corn vegetable, corn oil, corn flake.

Phytochemical compositions:

Phytochemicals are the non-nutritional bioactive compounds found in various parts of plants. In plants these compounds perform vital functions particularly protection from predators and harsh environmental conditions. These compounds are also important in pharmaceutical and medicinal field due to their antioxidant, antimicrobial, and other biological properties.

Various parts of corn plant such as silk, seed, stem, leaves, and roots are good sources of bioactive phytochemical compounds such as phenolic acids, flavonoids, steroids, alkaloids, carotenoids, tannins, saponins, anthocyanins, and other phenolic compounds. Corn seeds contain polyphenols, phenolic acids, flavonoids, anthocyanins, carotenoids, vitamins, sugars, polysaccharides, and other phytochemicals of medicinal importance. Corn silk contains a number of bioactive phytochemical compounds including phenols, polyphenols, phenolic acids, flavonoids, flavone glycosides, anthocyanins, carotenoids, terpenoids, alkaloids, steroids, luteins, tannins, saponins, volatile oils, vitamins, some sugars, and polysaccharides.

Health benefits of maize:

Maize has various health benefits. The B-complex vitamins in maize are good for skin, hair, heart, brain, and proper digestion. They also prevent the symptoms of rheumatism because they are believed to improve joint motility. The presence of vitamins A, C, and K together with beta-carotene and selenium helps to improve the functioning of thyroid gland and immune system. Potassium is a major nutrient present in maize which has diuretic properties. Maize silk has many benefits associated with it. In many countries of the world such as India, China, Spain, France and Greece it is used to treat kidney stones, urinary tract infections, jaundice, and fluid retention. It also has a potential to improve blood pressure, support liver functioning, and produce bile. It acts as a good emollient for wounds, swelling, and ulcers. Decoction of silk, roots, and leaves are used for bladder problems, nausea, and vomiting, while decoction of cob is used for stomach complaints (Kumar & Jhariya, 2013). Maize grains, especially the yellow variety contains large quantities of the carotenoid pigments and has a vital significance in the diet as human beings are not able to biosynthesize carotenoids. These pigments are also beneficial in preventing cancer. Anthocyanins have been well known for their health-promoting benefits such as anti-carcinogenic, anti-atherogenic, lipid lowering, anti-diabetic, antimicrobial, and anti-inflammatory properties. Due to the potent antioxidant properties they are able to decrease capillary permeability and fragility, immune system stimulation, and inhibit platelet aggregation (Ghosh & Konishi, 2007). The presence of essential fatty acids, especially linoleic acid in maize oil plays an important role in the diet by maintaining blood pressure, regulating blood cholesterol level, and preventing cardiovascular maladies. Its consumption influences cholesterol metabolism, lowers body fat storage therefore reduces the risk of atherosclerosis, hyperlipidemia, diabetes, and obesity. It can significantly shorten the intestinal transit time that leads to elimination of waste material through feces in a quicker time.