Coloured maize as a functional crop: Integrating bioactive pigments, nutritional quality and genetic improvement
Maize (Zea mays L.) is one of the world’s most important cereal crops, serving as a major source of calories, protein and industrial raw materials. However, conventional white and yellow cultivars are frequently deficient in essential micronutrients and health-promoting phytochemicals, contributing to widespread micronutrient malnutrition and hidden hunger in maize-dependent populations. Coloured maize genotypes are characterised by purple, blue, red and orange kernels. These genotypes represent an underutilised reservoir of nutritional and genetic diversity, enriched in anthocyanins, carotenoids, phenolic acids and minerals with strong antioxidant and functional properties. This review synthesises current knowledge on the nutritional composition, biochemical diversity and health relevance of coloured maize, emphasising the molecular regulation of flavonoid and carotenoid biosynthesis pathways and the roles of key structural and regulatory genes controlling pigment accumulation. The importance of traditional landraces and germplasm conservation in maintaining allelic richness for nutritional traits is discussed alongside advances in phenotyping, near-infrared spectroscopy, molecular markers and marker-assisted breeding. Progress in quality protein maize, provitamin A biofortification and the development of anthocyanin-rich sweet corn illustrate the integration of metabolic genetics with applied breeding strategies. Collectively, coloured maize is represented as a multifunctional crop capable of enhancing dietary quality, supporting functional food development and contributing to sustainable agricultural systems. Harnessing its genetic variability through genomics-assisted selection and targeted pathway engineering offers a promising route toward nutritionally superior, climate-resilient maize cultivars that can contribute to future food and nutritional security.