Quinoline Yellow
What it does
Yellow colour.
How it's made
Synthetic dye manufactured from coal-tar/petroleum intermediates.
Quinoline yellow is a synthetic greenish-yellow colour used in some sweets, drinks, cosmetics and medicines. It is a water-soluble dye that gives a bright, slightly green-tinged yellow distinct from the pure lemon of tartrazine.
It is produced by chemical synthesis, built around a quinoline structure. Manufacturing joins quinaldine-derived and phthalic-derived aromatic building blocks and then introduces sulphonic-acid groups (sulphonation) to make the pigment soluble in water. The result is a mixture of closely related sulphonated molecules that together make up the food colour.
The dye is purified and standardised to control impurities, then supplied as a yellow powder. Like several other synthetic colours permitted in the UK and EU, foods containing quinoline yellow must carry the warning about a possible effect on children's activity and attention.
Possible reactions
May worsen hyperactivity in some children; possible intolerance in asthmatics.