Researchers are turning a unique variety of corn into an effective natural alternative to artificial food dyes.

At University of Missouri’s College of Agriculture, Food, and Natural Resources, scientists are studying a variety of purple colored corn traditionally grown in South America.

Its vibrant shades come from anthocyanins, natural pigments that give blueberries, red cabbage and grapes their colors.

Unlike artificial dyes, which are petroleum-based and added purely for appearance, anthocyanins are rich in antioxidants known for reducing inflammation and supporting heart health.

In corn, these colors are concentrated in the pericarp, the thin outer layer of the kernel.

“It’s the layer that often gets stuck in your teeth,” says Pavel Somavat, who has joint appointments in Mizzou’s College of Agriculture, Food, and Natural Resources and the College of Engineering.

“In purple corn, that’s where our most valuable components are.”

For food manufacturers, replacing synthetic dyes such as Red No. 40 and Red No. 3 has long been a challenge.

“Most natural colors are fragile,” Somavat says. “They tend to break down when exposed to heat, light, or oxygen.”

That has become a major barrier in the food industry, where ingredients must withstand processing temperatures up to 250 degrees Fahrenheit and remain stable on store shelves for weeks or even months.

Mizzou’s team is tackling that problem head-on.

In testing, researchers exposed purple corn colorants to elevated temperatures often utilized in food processing. After one hour of exposure, about 75% of the key color compounds remained intact.

“If the color looks good after heating, that’s what matters to manufacturers,” Somavat says.

When the team coated the pigments in protective, food-grade materials, retention increased to nearly 97% for some compounds. That process allows researchers to create shelf-stable powders, making purple corn-based colorants easier to store and transport.

Researchers also tested their purple colorants in a beverage system, one of the most demanding environments for natural dyes. Drinks are often acidic, exposed to light and stored for extended periods—all conditions that can quickly degrade plant-based ingredients.

“Purple corn-based colorants held up well in acidic and basic environments,” Somavat says. “That makes it a strong candidate for fruit juices, flavored waters, and sports drinks. Even after seven weeks of refrigerated storage, color loss was minimal.”

That durability, combined with its potential health benefits, positions purple corn colorants as more than a niche ingredient. It offers food companies a viable path to cleaner labels without sacrificing performance. For consumers, that could mean replacing artificial dyes with natural ingredients.

Missouri is one of the nation’s leading producers of standard yellow corn.

For the past five years, Mizzou researchers have been working to adapt purple corn to growing conditions in the Corn Belt in hopes of expanding production and diversifying revenue streams for farmers.

In collaboration with Sherry Flint-Garcia, a research geneticist with the US Department of Agriculture’s Agricultural Research Service, the team is developing hybrid varieties that balance intense color with strong performance.

“Some of the most colorful types don’t grow well here, so we’re crossbreeding them with types of corn that already do well in places like Missouri,” Flint-Garcia says.

“That way, farmers can grow purple corn, and we can benefit from its healthy properties.”

The study appears in NPJ Science of Food.

Source: University of Missouri