Corn and maize are interchangeably used to refer to the plant scientifically known as Zea mays. Along with wheat and rice, corn is one of the three global staple cereals that forms a large part of the human diet and accounts for an estimated 42% of the world’s food calories and 37% of protein intake.
It is the leading cereal in terms of production volume and is set to become the most widely grown and traded crop in the coming years. Corn is more versatile than wheat and rice due to its role as an important food crop, particularly in Africa and Latin America, and as global livestock feed.
With the recent global food crisis and an ever-expanding population to sustain, investing in the research and development of corn could be vital to the future of global agri-food systems and food security.
Corn kernel: Boost the bran for more nutrients
Earlier this year, scientists from the University of Illinois, Jack Juvik, professor at the Department of Crop Sciences and co-author Michael Paulsmeyer, found that the nutritional quality of corn could be enhanced by adding cell layers to the bran. Iron could be increased by up to 35% whilst zinc up to 15% by altering multiple aleurone layers (MAL) which a few rare corn varieties produce. The scientists focused their study on the protein-rich aleurone layer, normally a single layer of cells located just inside the outer coating of a corn kernel.
Sourcing from the Maize Genetics Cooperation Stock Center, the researchers took two MAL lines, one from a yellow variety and another from a blue variety, both with multiple layers. Juvik and Paulsmeyer crossed them with normal corn varieties to understand how the MAL trait can enhance nutritional value in corn.
“The addition of MALs is a promising tool for breeders trying to elevate nutritional content of maize. The MAL trait increased anthocyanin production 20 to 30%, most likely due to an increase in aleurone yield. Iron content was significantly increased in MAL lines, but future studies will have to test micronutrient levels in near-isogenic MAL lines to reduce genetic variability,” explain the authors of the study.
Anthocyanin: A natural dye and potent antioxidant
Anthocyanin is a water-soluble plant pigment responsible for the blue, purple, and red colour found in berries, currants, grapes, and some tropical fruits. Leafy vegetables, grains, and tubers of a red to purplish colour also contain high levels of anthocyanin. It is traditionally used in food manufacturing as a natural dye and has potential use in nutraceutical and pharmaceutical industries with its antioxidant properties.
The original intention of the project was to increase the anthocyanin content in corn, according to the scientists. Juvik had been working on this for years, focusing on the pericarp, which then led to altering the overall nutrition. By increasing the amount of aleurone and pericarp, Juvik hoped to increase the amount of colour that could be extracted from corn. Samples were sent to a lab to be analysed for micronutrients and a significant increase of iron and zinc was discovered.
Juvik is still researching corn and using genetically identical corn hybrids to understand how MAL affects nutritional quality and anthocyanin content. Introducing the trait into hybrids where maize accounts for over 50% of staple diets and providing enough micronutrients to overcome nutritional problems in pregnant women and infants is the next plan, says Juvik.