When microbiology meets chemistry: generation, properties and prospects of pyranoanthocyanins as natural food colorants

Pyranoanthocyanins formed by the reaction of anthocyanins and low-molecular compounds originating mostly from microbial metabolism are promising natural food colorants which may have the potential to replace synthetic food additives. However, their industrial-scale application is still hampered mainly because of the long reaction periods and the low quantities obtained. Biotechnological approaches include the accelerated generation of educts, for example, by yeasts and lactic acid bacteria, and genetic engineering to use bacterial cells as factories of pyranoanthocyanin production. Once appropriate strategies are found, a better understanding of the behavior of pyranoanthocyanins in various food matrices is required, in particular with respect to their stability during processing and storage, and interactions with other food constituents.