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Carmine (// or //), also called crimson lake, cochineal, natural red 4, C.I. 75470, or E120, is a pigment of a bright-red color obtained from the aluminium salt of carminic acid, which is produced by some scale insects, such as the cochineal scale and the Polish cochineal, and is used as a general term for a particularly deep-red color of the same name. Carmine is used in the manufacture of artificial flowers, paints, crimson ink, rouge, and other cosmetics, and is routinely added to food products such as yogurt and certain brands of juice, the most notable ones being those of the ruby-red variety.
The English word "carmine" is derived from the French word carmin (12 c.), from Medieval Latin carminium, from Arabic qirmiz "crimson," from Sanskrit krimiga "insect-produced", from krmi "worm, insect". Influenced in Latin by minium "red lead, cinnabar", said to be of Iberian origin.
To prepare carmine, the powdered scale insect bodies are boiled in ammonia or a sodium carbonate solution, the insoluble matter is removed by filtering, and alum is added to the clear salt solution of carminic acid to precipitate the red aluminium salt, called "carmine lake" or "crimson lake." Purity of color is ensured by the absence of iron. Stannous chloride, citric acid, borax, or gelatin may be added to regulate the formation of the precipitate. For shades of purple, lime is added to the alum; thus, the traditional crimson color is guaranteed not only by carminic acid but also by choice of its chelating metal salt ion.
Carmine may be prepared from cochineal, by boiling dried insects in water to extract the carminic acid and then treating the clear solution with alum. Other common substances such as cream of tartar, stannous chloride, or potassium hydrogen oxalate can also be used to effect the precipitation, but aluminum is needed for the color. Use of these chemicals causes the coloring and animal matters present in the liquid to be precipitated to give a lake pigment. Aluminum from the alum gives the traditional crimson color to carminic acid precipitates, which are called carmine lakes or crimson lakes. This color is degraded by the presence of iron salts. Addition of lime (calcium) can give carminic acid lakes a purple cast.
The carminic acid used to produce the pigment can also be extracted from various microbes engineered for the purpose. Microbes are dissolved in a containment structure separate from their cultivation vats, and then allowed to settle out. The liquid and suspended carminic acid is then siphoned off, and metal salts are then added to give a lake pigment in a procedure that is mostly identical to the procedure for acid extracted from insects.
The quality of carmine is affected by the temperature and the degree of illumination during its preparation, sunlight being requisite for the production of a brilliant hue. It also differs according to the amount of alumina present in it. It is sometimes adulterated with cinnabar, starch and other materials; from these, the carmine can be separated by dissolving it in ammonia. Good carmine should crumble readily between the fingers when dry.
A reflectance spectroscopy study of one commercially available dye based on carminic acid found that it reflects mostly the red light with wavelengths longer than about 603 nm, which provides its saturated red color.
Carmine can be used as a staining agent in histology, as a Best's carmine to stain glycogen, mucicarmine to stain acidic mucopolysaccharides, and carmalum to stain cell nuclei. In these applications, it is applied together with a mordant, usually an Al(III) salt.
Carmine is used as a food dye in many different products such as juices, ice cream, yogurt, and candy, and as a dye in cosmetic products such as eyeshadow and lipstick. Although principally a red dye, it is found in many foods that are shades of red, pink, and purple. As a food dye it has been known to cause severe allergic reactions and anaphylactic shock in some people.
In January 2006, the United States Food and Drug Administration evaluated a proposal that would require food products containing carmine to list it by name on the ingredient label. It was also announced that the FDA will separately review the ingredient labels of prescription drugs that contain colorings derived from carmine. A request from the Center for Science in the Public Interest urged that the FDA should require ingredient labels to explicitly state that carmine may cause severe allergic reactions and anaphylactic shock and that it is derived from insects was declined by the FDA. Food industries were aggressively opposed to the idea of writing "insect-based" on the label, and the FDA agreed to allow "cochineal extract" or "carmine."
Although concerns over hazards from allergic reactions have been asserted, the FDA has not banned the use of carmine and states it found no evidence of a "significant hazard" to the general population. As with any material, the dye may still pose an allergen hazard to a subset of the population.
In the European Union, the use of carmine in foods is regulated under the European Commission's directives governing food additives in general and food dyes in particular and listed under the names Cochineal, Carminic acid, Carmines and Natural Red 4 as additive E 120 in the list of EU-approved food additives. The directive governing food dyes approves the use of carmine for certain groups of foods only and specifies a maximum amount which is permitted or restricts it to the quantum satis.
The EU-Directive 2000/13/EC on food labeling mandates that carmines (like all food additives) must be included in the list of ingredients of a food product with its additive category and listed name or additive number, that is either as Food colour carmines or as Food colour E 120 in the local language(s) of the market(s) the product is sold in.
Although concerns of hazards from allergic reactions were raised, the use of carmine in foods is not banned in the EU. However, the use of carmine in foods has been discouraged by European Food Safety Authorities, and, although it is used predominantly as coloring in alcoholic beverages, it can still be found in foods such as supermarket Indian curries. A re-evaluation process of the approval status of several food colors (including carmine) was started by the Panel on food additives, flavourings, processing aids and materials in contact with food of the EFSA in early 2006 and is scheduled to be completed by 2008.
As of January 2012, the European Food Safety Authority (EFSA) has changed the way they manufacture Carmine E120 for pharmaceutical products. The EFSA had raised concerns, over the increasing number of allergic reactions to Carmine derived from insects (E120.360), when used within the British pharmacopeia. Pharmaceutical products which had previously contained insect-derived carmine, have been replaced with a synthesised version of the food colorant. Internal studies have shown that the new formulations, of popular anti-nausea and weight-gain liquid medication, had a significantly lower risk in terms of allergic reactions. The new formulation is known to be of plant origin, using calcium oxide in order to gauge color depth.