Cochineal: Difference between revisions
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There are two main forms of cochineal dye: ''cochineal extract'' is a colouring made from the raw dried and pulverised bodies of insects, ''carmine'' is a more purified colouring made from cochineal. To prepare carmine, the powdered insect bodies are boiled in [[ammonia]] or [[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. Purity of colour 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 the shades of [[purple]], [[lime]] is added to the alum {{mn|tym|5}}. |
There are two main forms of cochineal dye: ''cochineal extract'' is a colouring made from the raw dried and pulverised bodies of insects, ''carmine'' is a more purified colouring made from cochineal. To prepare carmine, the powdered insect bodies are boiled in [[ammonia]] or [[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. Purity of colour 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 the shades of [[purple]], [[lime]] is added to the alum {{mn|tym|5}}. |
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The dried insects and extracts must conform to the buyer’s specification for very low maximum levels of bacteria{{mn|foo|3}}. The colouring comes from [[carminic acid|carminic (kermesic) acid]]. Cochineal extract natural carminic acid content is usually 19-22% {{mn|can|4}}. Cochineal is produced commercially only in [[Peru]], which produces about 200 tonnes per year {{mn|foo|3}}, and the [[Canary Islands]], which produces only about 20 tonnes per year{{mn|can|4}}. [[France]] is believed to be the world’s largest importer of cochineal, but [[Japan]] and [[Italy]] are also important direct importers. A high proportion of these imports are reexported in processed form, mainly to other developed economies{{mn|foo|3}}. |
The dried insects and extracts must conform to the buyer’s specification for very low maximum levels of bacteria{{mn|foo|3}}. The colouring comes from [[carminic acid|carminic (kermesic) acid]]. Cochineal extract natural carminic acid content is usually 19-22% {{mn|can|4}}. Cochineal is produced commercially only in [[Peru]], which produces about 200 tonnes per year {{mn|foo|3}}, and the [[Canary Islands]], which produces only about 20 tonnes per year{{mn|can|4}}. [[France]] is believed to be the world’s largest importer of cochineal, but [[Japan]] and [[Italy]] are also important direct importers. A high proportion of these imports are reexported in processed form, mainly to other developed economies{{mn|foo|3}}. As of time of writing in 2005, market price of cochineal is between 50 and 80 [[United States dollar|USD]] per kilogram{{mn|oxa|8}}. Recently two new producers have entered the market, [[Chile]] and Mexico {{mn|mex|1}}. |
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Recently new producers have entered the market, [[Chile]] and Mexico {{mn|mex|1}}. |
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===History=== |
===History=== |
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Revision as of 07:39, 15 July 2005
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Cochineal (Dactylopius coccus) is a scale insect in the order of Homoptera, native to tropical and subtropical South America and Mexico. A parasite, it lives primarily on the cactus Nopalea cochinillifera and cacti from the genus Opuntia, feeding on moisture in the cacti. The dried bodies of the females or eggs are the main source of expensive crimson or carmine red coloured dye primarily used as an food artificial colouring or for cosmetics named after the insect.
After synthetic pigments were invented in late 19th century, natural dye production gradually diminished. However, current health concerns over artificial food additives has renewed the popularity of cochineal dyes; increased demand making cultivation of the insect profitable againTemplate:Mn.
Biology
Cochineals are soft-bodied, flat, oval-shaped scale insects that cluster on cacti plants. The cacti pads are colonised by wingless female insects which are about 5 mm long. After mating the fertilised female increases in size and gives a birth to tiny nymphs. The nymphs secrete a waxy white substance over their bodies for protection from water and excessive sun. This substance makes the cochineal insect appear white or grey from the outside. The body of the insect and its nymphs produces a red pigment, which makes the insides of the insect look dark purple. The pigment is based on carminic acid and its purpose is to protect the insect from predators. Adult males are tiny compared to females, males have wings and they only live long enough to fertilise the eggs.Template:Mn
Distribution
Cochineals are native to tropical and subtropical South America and Mexico. Cochineals have also been introduced to Spain, Canary Island, Algiers and Australia.
Host cacti
All of the host plants of the cochineal colonies were identified Nopalea or as species of Opuntia including Opuntia amyclaea, O. atropes, O. cantabrigiensis, O. brasilienis, O. ficus-indica, O. fuliginosa, O. jaliscana, O. leucotricha, O. lindheimeri, O. microdasys, O. megacantha, O. pilifera, O. robusta, O. sarca, O. schikendantzii, O. stricta, O. streptacantha, and O. tomentosa Template:Mn.
The feeding of the female cochineal often causes damage and sometimes kills the host cactus plant. Immature males while being nymphs feed on a cactus for a short time, and when adult, males cannot feed at all.
Cochineal-laden cacti Opuntia stricta were introduced into Australia to produce cohcineal dye, but the introduction of the cactus had disastrous consequences. By 1925, 250000 km² of valuable range land was covered by prickly pear cactus. To control the spread of prickly pear cactus in Australia, the cactus moth (Cactoblastis cactorum) was introduced, and by 1930, vast areas of cactus scrub had been denuded by cactus moth larvae. Side effects have caused a havoc: the moth has attacked other species of cacti, some of which are rare and endangered Template:Mn.
Farming
The cochineal is farmed by planting already infected pads and protecting from predators, cold and rains. Several natural enemies can reduce the whole populations of this insect on its cacti hosts. Of all the predators, insects seem to be the most important group. Insects and their larvae as weaver worm, pyralid moth (order Lepidoptera), lady bug (Coleoptera), fly, drum worm (Diptera), needle worm (Neuroptera) and ant (Hymenoptera) have been identified. Many birds, including domestic, rodents, especially rats, and reptiles also are predators of cochineal population.
In regions, dependant on cochineal production, pest control measures have to be taken seriously. For small scale cultivation manual methods of control have proved to be the most effective and safe. For large scale cultivation advanced pest control methods have to be developed, including alternative bioinsecticides or traps with pheromones Template:Mn.
Dye
A deep crimson dye is extracted from the Cochineal insect females. Cochineal is used to produce scarlet, orange and other tints of red colour dyes, too.
The insects are collected when they are approximately ninety days old. The insects are knocked, brushed or picked from the cacti and placed into bags; it is a highly labor-intensive activity. The insects are gathered by small groups of collectors who sell them to local processors or exporters Template:Mn.
The insects are killed by either immersion in hot water (after which they are dried) or by exposure to sunlight, steam, or the heat of an oven. Each method produces a different colour whch is why there is a varied appearance of commercial cochineal. The immersion technique produces grey grains known as grey cochineal Template:Mn. Heating technique produces almost black grains known as black cochineal. The insects must be dried to about 30 per cent of their original body weight before they can be stored without decayingTemplate:Mn. It takes around 155,000 insects to make one kilogram of cochineal.
There are two main forms of cochineal dye: cochineal extract is a colouring made from the raw dried and pulverised bodies of insects, carmine is a more purified colouring made from cochineal. To prepare carmine, the powdered insect bodies are boiled in ammonia or 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. Purity of colour 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 the shades of purple, lime is added to the alum Template:Mn.
The dried insects and extracts must conform to the buyer’s specification for very low maximum levels of bacteriaTemplate:Mn. The colouring comes from carminic (kermesic) acid. Cochineal extract natural carminic acid content is usually 19-22% Template:Mn. Cochineal is produced commercially only in Peru, which produces about 200 tonnes per year Template:Mn, and the Canary Islands, which produces only about 20 tonnes per yearTemplate:Mn. France is believed to be the world’s largest importer of cochineal, but Japan and Italy are also important direct importers. A high proportion of these imports are reexported in processed form, mainly to other developed economiesTemplate:Mn. As of time of writing in 2005, market price of cochineal is between 50 and 80 USD per kilogramTemplate:Mn. Recently two new producers have entered the market, Chile and Mexico Template:Mn.
History
Cochineal was used by the Aztecs and Mayans. 11 cities conquered by Montezuma in 15th century paid a yearly tribute of 2000 decorated cotton blankets and 40 bags of Cochineal dye each Template:Mn. Spanish conquistadors introduced the dye from Mexico to Europe during the 17th century. The Mexican city of Oaxaca, Oaxaca, and its hinterland owed much of its prosperity in the 17th and 18th centuries to the cochineal trade. It has since been imported to and cultivated in other locations, such as Peru and the Canary Islands, where it became a lucrative export Template:Mn. The dye industry was so economically important, that it was third highest source of income for Spanish colonies after gold and silver exports. Once Mexico has been the first dye producer during the colonial period Template:Mn.
Recipes for artists' use of carmine appear in many early painting and alchemical handbooks throughout the Middle Ages. Carmine lakes appear frequently in European oil paintings from François Boucher to Raoul Dufy Template:Mn.
In the course of the 20th century, trade in cochineal diminished, as it was replaced by synthetic compounds, like alizarin crimson and many other substitute dyes. In recent years it has become commercially valuable again Template:Mn, because, unlike many commercial synthetic red dyes, it is non-toxic and not carcerogenic (however, some people are allergic to carmine).
Usage
Traditionally cochineal was used for colouring fabrics. Now it is used as a fabric and cosmetics dye and as a natural food colouring, as well as for oil paints, lake, pigments and watercolours. Cochineal dye coloured wool and cotton is still important material for Mexican folk art and crafts. When used as a food additive, the dye must be labelled on packaging labels Template:Mn. Sometimes Carmine is labelled as E120. An unknown percentage of people have been found to have allergies to carmine, ranging from mild cases of hives, to anaphylactic shock. Carmine has been found to cause asthma in some people Template:Mn. Cochineal is one of the colours that the Hyperactive Children's Support Group recommends be eliminated from the diet of hyperactive children.
The water soluble form is used in alcoholic drinks with calcium carmine, the insoluble form, being used in a wider variety of products. Together with ammonium carmine they can be found in alcoholic drinks, bakery products and toppings, biscuits, desserts, drinks, icings, pie fillings, variety of cheddar cheese, sauces and sweets. It gives Campari and other Italian aperitifs their colour, tooTemplate:Mn.
Carmine is one of the very few pigments considered safe enough for use in eye cosmetics Template:Mn. A bright red dye and the biological stain carmine used in microbiology is often made from the carmine extract, too Template:Mn. The pharmaceutical industry uses cochineal to colour pills and ointments Template:Mn.
Natural carmine dye used in food can render it rather unattractive to vegetarian consumers, and Muslims consider carmine containing food forbidden (haraam), because insects are used in dye production.
References
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Template:Mnb"Canary Islands cochineal producers homepage". July 14. {{cite web}}: Check date values in: |date= and |year= / |date= mismatch (help)
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Template:Mnb"Cultivation of Cochineal in Oaxaca". Go-Oaxaca Newsletter. July 15. {{cite web}}: Check date values in: |date= and |year= / |date= mismatch (help)