Amaranth
What it does
Dark red colour.
How it's made
Synthetic azo dye from petroleum.
Amaranth is a synthetic dark reddish-purple azo colour. Its permitted uses in the UK and EU are now quite limited — it is mainly restricted to a few applications such as certain drinks and fish roe — but where allowed it gives a deep bluish-red.
It is made by azo-dye synthesis from petroleum-derived aromatic compounds: an aromatic amine is diazotised and coupled to a naphthalene-based partner carrying sulphonic-acid groups, producing the coloured azo molecule and making it water-soluble.
The dye is purified and standardised to control residual reactants and by-products. Amaranth is more tightly regulated than some other azo colours, and its use is confined to the specific foods and levels set out in food-colour legislation.
Possible reactions
Banned in the US; may trigger reactions in aspirin-sensitive and asthmatic people.