Gum arabic

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 stabilizer, but has had more varied uses in the past, including viscosity control in inks. Its E number is E414.

Gum arabic is a complex mixture of saccharides and glycoproteins, 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 (also known as Meska) mixture of saccharides and glycoproteins 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 syrups, "hard" gummy candies like gumdrops, marshmallows, M & M's chocolate candies, and most notably, chewing gums. For artists it is the traditional binder used in watercolor paint, and is used in photography for gum printing. Pharmaceuticals 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 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

Gum arabic is used as a 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 bichromate photography uses gum arabic to permanently bind pigments on paper. Ammonium or potassium dichromate is mixed with gum arabic and pigment to create a photographic emulsion, sensitive to ultraviolet light.

Printmaking

Gum arabic is also used to protect and etch an image in 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 blacks. 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 liquids, which leads to increased fizzing in carbonated beverages. This can be exploited in what is known as a Diet Coke and Mentos eruption.

Production

. Sudan, Chad, and Nigeria -- which in 2007 produced 95 percent of world exports -- have been in discussions to create a producer's cartel. [ [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.]

Political aspects

enegambia

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. [ [http://encyclopedia.jrank.org/APO_ARN/ARGUIN.html ARGUIN] , Encyclopedia Britannica (1911).] 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 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 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. [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.] 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 independence in 1959-61.

udan

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. [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 ] However it is still the world's largest single producer, and the production of gum arabic is heavily controlled by the Sudanese government.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]

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.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] 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 attacks, which echoed this claim. Eventually, the 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.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]

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.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]

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.

References

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)