Gum arabic
288420
225559078
2008-07-14T08:51:53Z
Plantsurfer
1750837
Reverted 1 edit by [[Special:Contributions/76.188.59.136|76.188.59.136]] identified as [[WP:VAND|vandalism]] to last revision by [[User:T L Miles|T L Miles]]. ([[WP:TW|TW]])
[[Image:Koeh-004.jpg|thumb|right|The [[Acacia senegal]], pictured in a medicinal handbook: [[Franz Eugen Köhler]], ''Köhler's Medizinal-Pflanzen'' (1887).]]
'''Gum arabic''', a [[natural gum]] also called '''gum acacia''', and '''chaar gund''' or '''char goond''' (in India), is the hardened [[sap]] taken from two species of the [[acacia]] tree, ''[[Acacia senegal]]'' and ''[[Acacia seyal]]''. It is used primarily in the [[food industry]] as a [[Food_additive#Categories|stabilizer]], but has had more varied uses in the past, including [[viscosity]] control in [[ink]]s. Its [[E number]] is E414.
Gum arabic is a complex [[mixture]] of [[saccharide]]s and [[glycoprotein]]s, which gives it its most useful property: it is perfectly edible. While historically used for printing, paint production, glue, and industrial applications, it continues to be used as an ingredient in foodstuffs.
The substance is harvested commercially from wild trees throughout the [[Sahel]] from [[Senegal]] and [[Sudan]] to [[Somalia]], although it has been historically cultivated in [[Arabia]] and [[West Asia]].
==Usage==
Gum arabic's [[mixture]] of [[saccharide]]s and [[glycoprotein]]s means that it is a glue, binder, and preparation agent which still remains edible by humans. Other substances have replaced it in situations where [[toxicity]] is not an issue, as the proportions of the various chemicals in gum arabic vary widely and make it unpredictable. Still, it remains an important ingredient in [[soft drink]] [[syrup]]s, "hard" gummy candies like [[gumdrops]], [[marshmallow]]s, M & M's chocolate candies, and most notably, [[chewing gum]]s. For [[artist]]s it is the traditional [[Binder (material)|binder]] used in [[watercolor]] [[paint]], and is used in photography for [[gum printing]]. [[Pharmaceutical]]s and [[cosmetics]] also use the gum, and it is used as a binder in [[pyrotechnic]] compositions. It is an important ingredient in [[shoe polish]]. It is also used often as a lickable [[adhesive]] on [[postage stamp gum|postage stamps]] and [[cigarette papers]]. Printers employ it to stop [[oxidation]] of [[aluminium]] [[printing]] plates in the interval between processing of the plate and its use on a [[printing press]].
===Painting and art===
[[Image:Gouache.jpg|thumb|right|A selection of [[Gouache]]s containing Gum Arabic.]]
Gum arabic is used as a [[binder (material)|binder]] for [[watercolor painting]] because it dissolves easily in water. [[Pigment]] of any color is suspended within the gum arabic in varying amounts, resulting in watercolor paint. Water acts as a vehicle or a [[diluent]] to thin the watercolor paint and helps to transfer the paint to a surface such as [[paper]]. When all moisture evaporates, the gum arabic binds the pigment to the [[paper]] surface.
====Photography====
The historical [[photography]] process of [[gum printing|gum bichromate photography]] uses gum arabic to permanently bind pigments on paper. [[Ammonium dichromate|Ammonium]] or [[potassium dichromate]] is mixed with gum arabic and [[pigment]] to create a photographic [[emulsion]], sensitive to [[ultraviolet|ultraviolet light]].
====Printmaking====
Gum arabic is also used to protect and [[etching|etch]] an image in [[lithography|lithographic processes]]. [[Ink]] tends to fill into [[whitespace]] on [[photosensitive]] aluminium plates if they don't receive a layer of gum. In [[lithography]] the gum etch is used to etch the most subtle gray tones. [[Phosphoric acid]] is added in varying concentrations to the gum arabic to etch the darker tones up to dark [[black]]s. Multiple layers of gum are used after the etching process to build up a protective barrier that ensures the [[ink]] does not fill into the whitespace of the image being printed.
===Pyrotechnics===
Gum arabic is also used as a water soluble binder in [[firework]] composition.
==Chemical properties==
=== Effect on surface tension in liquids ===
Gum arabic reduces the [[surface tension]] of [[liquid]]s, which leads to increased fizzing in [[carbonated beverage]]s. This can be exploited in what is known as a [[Diet Coke and Mentos eruption]].
==Production==
[[Image:Acacia_senegal_Taub68.png|thumb|left|[[Acacia senegal]] from Paul Hermann Wilhelm Taubert's Leguminosae. in Engelmann (ed.): Natürliche Pflanzenfamilien. Vol. III, 3., 1891]]
[[Image:Acacia seyal Taub66.png|thumb|left|[[Acacia seyal]] from Paul Hermann Wilhelm Taubert's Leguminosae. in Engelmann (ed.): Natürliche Pflanzenfamilien. Vol. III, 3., 1891]] While Gum Arabic has been harvested in [[Arabia]], [[Egypt]], and [[West Asia]] since antiquity, Sub-Saharan Gum Arabic has a long history as a prized export. The Gum exported came from the band of [[Acacia]] trees which once covered much of the [[Sahel]] region: the southern littoral of the [[Sahara Desert]] running from [[Atlantic Ocean|the Atlantic]] to the [[Red Sea]]. Today the main populations of gum producing Acadia species are harvested in [[Mauritania]], [[Senegal]], [[Mali]], [[Burkina Faso]], [[Niger]], [[Nigeria]], [[Chad]], [[Cameroon]], [[Sudan]], [[Eritrea]], [[Etiopia]], [[Somalia]], [[Kenya]] and [[Tanzania]]. The [[Acacia senegal]] variety is tapped (by cutting holes in the bark) for a product called ''Kordofan'' or ''Senegal gum''. ''Seyal gum'', from the [[Acacia seyal]] variety (more prevalent in [[East Africa]]) is collected through naturally occurring extrusions in the bark. Traditionally harvested by semi-nomadic desert pastorlists in the course of their [[transhumance]] cycle, Gum Arabic remains a main export of several African nations, including [[Agriculture in Mauritania|Mauritania]], [[Economy of Niger|Niger]], [[Economy of Chad|Chad]], and [[Economy of Sudan|Sudan]]. The hardened extrusions are collected in the middle of the rainy season (harvesting usually begins in July), and exported at the start of the dry season (November). The primary export agent for these nations continues to be a French company, ([[Colloïdes Naturels International ]]) founded during [[French colonial empire|the colonial period]] to process the Gum, which maintains large processing facilities in Nigeria and [[Rouen]], [[France]].<ref>[http://www.cniworld.com/ CNI World corporate website: "acacia gum", "Botanical", "100 years in Africa", "Harvest" sections]. Retrieved 2008-07-10. </ref> Total world Gum Arabic exports are today (2008) estimated at 60,000 tonnes, having recovered from 1987-1989 and [[2004 locust outbreak|2003-2005 crises]] caused by the destruction of trees by [[Desert locust]]. Sudan, Chad, and Nigeria -- which in 2007 produced 95 percent of world exports -- have been in discussions to create a producer's cartel.<ref>[http://news.yahoo.com/s/afp/20080710/lf_afp/sudanfoodtradesanctions;_ylt=AqWws4vGW3WKGFsDZ4FGOvm96Q8F Sudan's manna from heaven and strategic weapon], Alain Navarro (AFP) Thu Jul 10 2008.</ref>
===Political aspects===
====Senegambia====
In 1445, Prince [[Henry the Navigator]] set up a trading post on [[Arguin]] island (off the coast of modern Mauritania), which acquired [[gum arabic]] and [[slaves]] for Portugal. With the merger of the Portuguese and Spanish crowns in 1580, the Spaniards became the dominant influence along the coast. In 1638, however, they were replaced by the Dutch, who were the first to begin exploiting the gum arabic trade. Produced by the acacia trees of [[Trarza]] and [[Brakna]] and used in textile pattern printing, this gum arabic was considered superior to that previously obtained in [[Arabia]]. By 1678 the French had driven out the Dutch and established a permanent settlement at Saint Louis at the mouth of the Senegal River, where the French Company of the Senegal River (Compagnie Française du Sénégal) had been trading for more than fifty years.<ref>[http://encyclopedia.jrank.org/APO_ARN/ARGUIN.html ARGUIN], [[Encyclopedia Britannica]] (1911).</ref>
[[Image:GommeBakel.jpg|thumb|right|[[Moorish]] tribes meet to trade Gum Arabic at [[Bakel]] on the [[Senegal river]], 1890. (illustration from "''Côte occidentale d'Afrique du Colonel Frey''", pl. en reg. p. 100)]]
For much of the 19th century, Gum Arabic was the major export from French and British trading colonies in modern [[Senegal]] and [[Mauritania]]. France in particular first came into conflict with inland African states over the supply of the commodity, providing an early spur for the conquest of [[French West Africa]]. As the [[Atlantic Slave Trade]] weakened in the early 19th century, The [[Emirate of Trarza]] and its neighbors in what is today southern Mauritania collected taxes on trade, especially Gum Arabic, which the French were purchasing in every increasing quantities for its use in industrial fabric production. West Africa had become the sole supplier of world Gum Arabic by the 18th century, and its export at the French colony of [[Saint-Louis, Senegal|Saint-Louis]] doubled in the decade of 1830 alone. Taxes, and a threat to bypass Saint-Louis by sending gum to the British traders at [[Portendick]], eventually brought the Emirate of Trarza into direct conflict with the French. In the 1820s, the French launched the [[Franco-Trarzan War of 1825]]. The new emir, [[Muhammad al Habib]], had signed an agreement with the [[Waalo|Waalo Kingdom]], directly to the south of the river. In return for an end to raids in Waalo territory, the Emir took the heiress of Waalo as a bride. The prospect that Trarza might inherit control of both banks of the Senegal struck at the security of French traders, and the French responded by sending a large expeditionary force that crushed Muhammad's army. The war incited the French to expand to the north of the [[Senegal River]] for the fist time, heralding French direct involvement in the interior of [[West Africa]].<ref>James L. A. Webb Jr. The Trade in Gum Arabic: Prelude to French Conquest in Senegal. The Journal of African History, Vol. 26, No. 2/3 (1985), pp. 149-168.</ref> Gum Arabic continued to be exported in large quantities from the Sahel areas of [[French West Africa]] (modern Senegal, Mauritania, Mali, Burkina Faso, and Niger) and [[French Equatorial Africa]] (modern Chad) until these nations gained their [[Decolonization|independence]] in 1959-61.
====Sudan====
Although from the 1950s to the early 1990s Sudan accounted for roughly 80 percent of gum arabic production, today that figure is under 50 percent.<ref>See page 4 of the World Bank Policy Note, Export Marketing of Gum Arabic from Sudan, March 2007 - http://siteresources.worldbank.org/INTAFRMDTF/Resources/Gum_Arabic_Policy_Note.pdf </ref> However it is still the world's largest single producer, and the production of gum arabic is heavily controlled by the Sudanese government.<ref name="seattletimes">{{cite web |url=http://seattletimes.nwsource.com/html/nationworld/2003726884_sudan30.html |title=Impact of Bush's Sudan sanctions doubted |author=James Gerstenzang and Edmund Sanders |publisher=Los Angeles Times |date=2007-05-30 |accessdate=2007-06-01}}</ref>
The connection between [[Sudan]] and [[Osama bin Laden]] brought the otherwise innocuous gum to public consciousness in 2001, as an [[urban legend]] arose that bin Laden owned a significant fraction of the gum arabic production in [[Sudan]] and that therefore one should [[boycott]] products using it.<ref name="snopes">{{cite web |url=http://www.snopes.com/rumors/arabic.htm |title=Urban Legends Reference Pages: Rumors of War (Buy Gum!) |publisher=Snopes |date=2001-09-19 |accessdate=2007-06-01}}</ref> As a result, some [[food]] producers, such as [[Snapple]], renamed the ingredient to "gum acacia" on their labels.
This story took on somewhat significant proportions, mostly thanks to an article in ''[[The Daily Telegraph]]'' a few days after the [[September 11, 2001 Terrorist Attacks|September 11 attacks]], which echoed this claim. Eventually, the [[United States Department of State|State Department]] issued a release stating that while Osama bin Laden had once had considerable holdings in Sudanese gum arabic production, he divested himself of these when he was expelled from Sudan in [[1996]].<ref name="baltimoresun">{{cite web |url=http://pqasb.pqarchiver.com/baltsun/access/34069223.html?dids=34069223:34069223&FMT=ABS&FMTS=ABS:FT&type=current&date=Sep+15%2C+1998&author=Tom+Bowman+and+Ann+LoLordo&pub=The+Sun&desc=Sanctions+on+Sudan+bend+for+gum+supply%3B+%60Terrorist+nation%27+allowed+exception+on+key+U.S.+food+element |title=Sanctions on Sudan bend for gum supply… |author=Tom Bowman and Ann LoLordo |publisher= The Sun - Baltimore, Md. |date=1998-09-15 |accessdate=2008-02-21}}</ref>
In a press conference held at the Washington Press Club on [[30 May]], [[2007]], John Ukec Lueth Ukec, Sudan's ambassador to the United States, threatened to stop exportation of gum arabic from his country if sanctions were imposed. The sanctions proposed by the United States were a political response from the United States to the alleged connection between the government of Sudan and the [[Janjaweed]] militia group. Ukec made his speech surrounded by Coca-Cola products, although other sodas use gum arabic as an emulsifier as well.<ref name="washingtonpost">{{cite web |url=http://www.washingtonpost.com/wp-dyn/content/article/2007/05/30/AR2007053002157.html?hpid=topnews |title=Denying Genocide in Darfur -- and Americans Their Coca-Cola |author=Dana Milbank |publisher=The Washington Post |date=2007-05-31 |accessdate=2007-06-01}}</ref>
John Ukec Lueth Ukec was quoted at the Washington press conference, "I want you to know that the gum arabic which runs all the soft drinks all over the world, including the United States, mainly 80 percent is imported from my country," which he said after raising a bottle of Coca-Cola. According to the ''Washington Post'', a reporter then asked if Sudan was threatening to "stop the export of gum arabic and bring down the Western world." To which Ukec replied, "I can stop that gum arabic and all of us will have lost this," and gestured to the Coke bottle.<ref name="washingtonpost"/>
==References==
{{Reflist|2}}
==External links==
*http://www.sbu.ac.uk/water/hyarabic.html
*http://www.cniworld.com (CNI : Colloides Naturels International is the Gum Arabic World Leader)
*http://www.npr.org/templates/story/story.php?storyId=11224050 ([[NPR]] story on Gum Arabic, its production, and use in industry)
[[Category:Agricultural products of Africa]]
[[Category:Food ingredients]]
[[Category:Crops]]
[[Category:Gums]]
[[Category:Agriculture in Sudan]]
[[Category:Agriculture in Niger]]
[[Category:Agriculture in Chad]]
[[Category:Agriculture in Mauritania]]
[[Category:Agriculture in Senegal]]
[[Category:Agriculture in Nigeria]]
[[ar:صمغ عربي]]
[[cs:Arabská guma]]
[[da:Gummi arabikum]]
[[de:Gummi arabicum]]
[[es:Goma arábiga]]
[[fa:صمغ عربی]]
[[fr:Gomme arabique]]
[[gl:Goma arábiga]]
[[id:Gom arab]]
[[it:Gomma arabica]]
[[he:גומי ערבי]]
[[hu:Gumiarábikum]]
[[nl:Arabische gom]]
[[ja:アラビアガム]]
[[no:Gummi arabikum]]
[[pl:Guma arabska]]
[[pt:Goma-arábica]]
[[ro:Gumă arabică]]
[[ru:Гуммиарабик]]
[[fi:Arabikumi]]
[[sv:Gummi arabicum]]