Traditional extraction methods, used to obtain this type of dye,
have several drawbacks, such as involving much time, hard work,
low selectivity and low extraction efficiency. Moreover, these conventional
techniques use large amounts of toxic solvents. The
recovery and purification of carminic acid from raw cochineal is
regarded as a difficult and complicated process. Conventional
industrial cochineal processing is a multiple step procedure consisting of treatment with organic solvents, alkaline extraction,
solid–liquid separation (flocculation and filtration), insoluble lake
formation, recovery of the precipitate (centrifugation), resolubilisation
of carminic acid and concentration. Besides, these processes
are known to be characterised by low yields and usually provide
low quality products. Incorporation of varying amounts of toxic
metal ions and allergenic proteins (insect-derived proteins, possibly
complexes with carminic acid) in the final carminic acid preparation
is common. This may have a negative impact on consumer
health.