Scientists are developing purple maize cultivars for the production of natural food colorants.

Specialists at the University of Missouri College of Agriculture, Food and Natural Resources are studying the potential of using purple corn as an alternative to synthetic food dyes. The rich color of the kernels is due to a high content of anthocyanins — plant pigments that possess antioxidant properties. These compounds are concentrated in the pericarp, the thin outer layer of the corn kernel.

The main problem with most natural dyes lies in their low stability when exposed to light, oxygen, and high temperatures. In the food industry, ingredients must withstand processing heat of up to 250 degrees Fahrenheit and remain stable during long-term storage. During testing, about 75% of the purple corn color compounds retained their properties after one hour of exposure to high temperatures. When using food-grade protective coatings, the pigment retention rate increased to nearly 97%, which allows for the creation of powders that are convenient for transport and storage.

The researchers also tested the dyes in beverages, which are characterized by an acidic environment and long shelf lives. According to Pawat Somavat, who works at the College of Agriculture, Food and Natural Resources and the College of Engineering, the dyes showed high stability in both acidic and alkaline conditions. Even after seven weeks of refrigeration, color changes were minimal, making this product promising for use in the production of fruit juices, flavored water, and sports drinks.

Over the last five years, scientists have been working on adapting South American cultivars to growing conditions in the "Corn Belt." In collaboration with geneticist Sherry Flint-Garcia from the USDA Agricultural Research Service, hybrids are being developed. The goal of the breeding work is to create cultivars that combine intense color and the ability to grow successfully in the climatic conditions of Missouri, providing farmers with new sources of income.