Red colourants from filamentous fungi: Are they ready for the food industry?

Abstract

Food components of microbial-origin have a long history in food science and the food industry. Thickening and gelling agents, flavour enhancers, polyunsaturated fatty acids, flavour compounds, vitamins, essential amino acids, and acidulants are some examples of such ingredients. This paper will provide an update on the current worldwide situation for four different fungal reds: (i) carotenoid lycopene (simple compound, complex current status); (ii) molecular biology on Monascus to avoid mycotoxin and cholesterol-lowering substance in pigmented extracts; (iii) newcomers with azaphilone-producing fungi such as Talaromyces atroroseus, Penicillium purpurogenum, and Talaromyces albobiverticillius; and (iv) anthraquinones as a possible alternative to the insect-sourced carmine. The future of Monascus in Europe and the USA is just around the corner, and markets will appear as soon as the citrinin issue has been solved, with the help of the current better knowledge of full genomes from industrial strains. Fungi bring a new class of pigments to the food industry, as azaphilones are not present in plants. These azaphilone-producing strains should now be thoroughly studied through liquid fermentation of Penicillium/Talaromyces strains, with optimized scale-up. A fungal alternative to carmine insect anthraquinone is further away from the market, however, due to the particular stability of this vibrant red in foods; research efforts should be intensified.