Erythrosine
What it does
Pink/red colour.
How it's made
Synthetic iodine-containing dye.
Erythrosine is a synthetic cherry-pink to red colour, distinctive for containing iodine in its structure. It is used in a limited range of foods, most typically cocktail and glacé cherries, where its bright pink is characteristic.
Unlike the azo dyes, erythrosine belongs to the xanthene family and is made by chemically adding iodine to a fluorescein-type dye molecule. The fluorescein backbone is synthesised from aromatic feedstocks and then iodinated, attaching iodine atoms that shift the colour to the deep pink-red of erythrosine, and sulphonate/sodium groups make it water-soluble.
The dye is purified and standardised, with controls on impurities, and supplied as a red-brown powder that dissolves to a cherry-pink solution. Its use is fairly restricted, and it is chosen mainly where its particular shade and affinity for certain foods, such as preserved cherries, are wanted.
Possible reactions
High iodine content; may affect thyroid at very high intakes.