Prospects for economical natural colorants: insights from maize

Replacing artificial dyes with natural colorants is becoming increasingly popular in foods and beverages. However, natural colorants are often expensive, have lower stability, and reduced variability in hue. Purple corn is rich in anthocyanins and offers a scalable and affordable alternative to synthetic dyes ranging in color from orange to reddish-purple. This diversity is attributable to differences in anthocyanin composition and concentration. Here we review the chemistry, biosynthesis, and genetics of purple corn and outline key factors associated with the feasibility of producing an economical source of natural colorants. Anthocyanin compositional modifications including acylation, methylation, and polymerization with flavan-3-ols can influence color stability and hue, yet there is more to learn regarding the genetic factors responsible for these modifications. Activators and repressors of anthocyanin biosynthesis structural genes as well as factors controlling trafficking and storage largely control anthocyanin yield. Further knowledge of these mechanisms will allow breeders to apply molecular strategies that accelerate the production of purple corn hybrids to meet growing demands for natural colorants.