Allura Red AC
What it does
Red colour.
How it's made
Synthetic azo dye from petroleum.
Allura red AC is a synthetic red azo colour used widely in drinks, sweets, sauces and snacks, giving a bright, slightly orange-red. It is very water-soluble and is one of the most common red food dyes in many products.
It is made by the usual azo-dye synthesis from petroleum-derived aromatic compounds: an aromatic amine is diazotised with nitrous acid and coupled to a naphthalene sulphonic-acid partner, forming the azo bond that gives the red colour while sulphonic-acid groups make it dissolve in water.
The crude dye is purified and standardised, with strict limits on unreacted materials, and supplied as a dark red powder. As an azo colour permitted in the UK and EU, foods containing Allura red must carry the warning about a possible effect on activity and attention in children.
Possible reactions
Linked to hyperactivity in some children; occasional intolerance.