Gum arabic

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Image:Koeh-004.jpg Gum arabic, a natural gum also called gum acacia, is a substance that is taken from two sub-Saharan 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 E-414.

The gum produced by the trees in question reseals the plant's bark in the event of damage - a process called gummosis.

Gum arabic is a complex mixture of saccharides and glycoproteins, which gives it one of its most useful properties: it is perfectly edible. Other substances have replaced it in situations where toxicity is not an issue, as the proportions of the various chemicals in gum arabic varies widely and make its reliable performance troublesome. Still, it remains an important ingredient in soft drink syrups, "hard" gummy candies like gumdrops, and in marshmallows. For artists it is the traditional binder used in watercolor paint, and was 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 aluminum printing plates in the interval between processing of the plate and its use on a printing press.

The substance is grown commercially throughout the Sahel from Senegal to Sudan.

1 Painting and Art
- 1.1 Photography
2 Terrorist rumors
3 Witchcraft
4 Effect on surface tension in liquids
5 External links

[edit] Painting and Art

Gum arabic is used as a binder for Watercolor painting because of it's ability to easily dissolve 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.

[edit] Photography

The historical photography process of Gum Bichromate Photography uses gum arabic to permanently bind pigments on paper. The chemical Ammonium dichromate or Potassium dichromate is mixed with gum arabic and pigment to create a photographic emulsion, sensitive to ultravioletlight.

[edit] Terrorist rumors

Oddly, 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 ([1]). As a result some food producers, for instance Snapple, renamed the ingredient "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, which echoed this claim. Eventually the US 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.