Phycocyanobilin is a blue tetrapyrrole chromophore that occurs in cyanobacteria such as Arthrospira spp. and in chloroplasts of other organisms. It is the terminal energy acceptor in the phycobiliproteins phycocyanin and allophycocyanin.
Phycocyanobilin-containing spirulina extract from cyanobacteria has recently come on the market as a natural food coloring. It was approved for this use by the US Food & Drug Administration in August 2013. It joins turmeric, β-carotene, and carmine as natural food colors that are used in candy and chewing gum.
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