Pigmented wheat: Metabolomics-enabled insights into grain pigmentation towards nutritional and functional foods

Abstract

Pigmented wheat, a unique germplasm with diverse grain colors (purple, blue, black, yellow, etc.), has emerged as a valuable resource for functional food development due to its enrichment in bioactive metabolites. However, critical knowledge gaps remain regarding metabolic differences among distinct-colored wheat cultivars and the specific health-benefiting metabolites validated by biochemical and nutritional studies. Addressing these gaps will facilitate biotechnological breeding and, more importantly, promote nutritional food development. This short review summarizes current advances in pigmented wheat metabolism, covering analytical technologies, characteristic metabolites, biosynthetic pathways, and metabolic comparisons among distinct-colored wheat cultivars. High-performance liquid chromatography (HPLC) and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) are among the primary tools for the separation and identification of metabolites when analyzing wheat grain pigmentation. Comparative analysis reveals distinct metabolic profiles: red wheat is rich in procyanidins and phenolic acids; purple/blue wheat contains specific anthocyanin derivatives (cyanidin, peonidin, delphinidin) with spatial distribution variations; yellow wheat is enriched in carotenoids; and black wheat synergistically accumulates anthocyanins and procyanidins. Pigment biosynthesis of major metabolites (e.g., flavonoids, anthocyanins, procyanidins) follows the conserved phenylpropanoid-flavonoid pathway, regulated by key metabolic enzymes (PAL, CHS, DFR, ANS, etc.) and transcription factors (TaMYB10, TaMYC1, etc.), with environmental factors modulating metabolite accumulation. Despite numerous identified secondary metabolites in pigmented wheat grains, only a few have demonstrated health benefits through biochemical, nutritional, or medical studies, providing a foundation for functional food development targeting specific populations. Future studies should prioritize multi-omics-based regulatory network analyses, metabolite database construction, and technological optimization for nutritional quality improvement and functional food development. This review provides a theoretical basis for exploiting the nutritional and commercial potential of pigmented wheat in functional food innovation.