Nopalea coccinellifera

Cochineal extract (Colour Index 75470, E 120)is the final alcohol-free material obtained after aqueous ethanolic extraction of the dried bodies of the female scale insect Dactylopius coccus Costa which lives on cacti such as Opuntia or Nopalea coccinellifera a species indigenous to Peru and Mexico, although also found in the Canary Islands. In practice a simpler procedure consists of aqueous alkaline extraction. The colourant principle is carminic acid which is more well-known in the form of carmine, an aluminium chelate of carminic acid, a material insoluble in water and stable on the acidic side. A uv spectrophotometric study has been made (ref. 21). Thin layer chromatography of cochineal has been examined on acetylated cellulose with the solvent system, ethyl acetate-tetrahydrofuran-water (6 35 47) in which the Rf was 0.94 (refs.22,23). The history of the chemistry of cochineal has been discussed (ref.24). 

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