Gum Arabic: History and Uses

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Gum Arabic is a gummy exudation from the branches of the Acacia Senegal (L.) Willd and other species of the Leguminosae Family. It is also known as Gum Acacia, Kordofan Gum, Gum Senegal, Acacia Vera, Gummi Africanum,  Gummae Mimosae, kher, Sudan Gum Arabic, Somali Gum, Yellow Thorn, Mogadore Gum, Indian Gum  and Australian Gum. The variety of names is due to the different places, and types of Acacias, from where the Gum Arabic can be extracted. Many of these trees behave the same and have similar appearance, differing only in some technical characters. shutterstock_137959859These Acacias are spiny shrubs or small trees that prefer sandy or sterile regions with a dry climate. This means that most Acacias can be found in North Africa, particularly in Sudan, and to a lesser degree in the Arabian Peninsula, India, and Australia.  During times of drought, the bark of these trees splits, exuding a sap that dries in small droplets or “tears.”  The colour of these oval “tears” can range from white to shades of orange-red. They are usually harvested in December, and it usually takes about five weeks. The masses of gum are then collected while they are still stuck to the tree or after they have fallen on the ground. Historically, these gum pieces were packed in baskets and very large sacks of tanned leather and then taken on camels and bullocks to trading centers in North Africa. Nowadays, commercial acacia gum is derived by tapping trees periodically and collecting the sap semi-mechanically.

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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).

There are at least three different grades of Gum Arabic available commercially and their quality is distinguished by the colour and character of the collected “tears”.

Even though the structure of  Gum Arabic is not completely known, it is basically composed of a high molecular weight polysaccharide that contains residues of neutral sugars and acids. This mixture of polysaccharides and glycoproteins gives it the properties of a glue and binder that is edible by humans. Acacia gum has long been used in traditional medicine and in everyday applications. The Egyptians used the material as a glue and as a pain-reliever base. Arabic physicians treated a wide variety of ailments with the gum, resulting in its current name. Gum Arabic  was used for making emulsions and as an ingredient in compounds for the treatment of diarrhea, catarrh, etc.  It is used topically for healing wounds and has been shown to inhibit the growth of periodontic bacteria and the early deposition of plaque. In addition, it has been one of the ingredients in cough syrups, tinctures, and pill coating from the early 19th century onward.

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Gum Arabic from the Herb Garret.

If these medicinal uses were not enough, Gum Arabic has been used by artists as one of the binding agents in tempera paint and gilding, and watercolours. In ceramics it is used in glazes in order to help them adhere to the clay before it is fired. Photographers have used it for gum printing and it is also used to protect and etch an image in lithographic processes, both from traditional stones and aluminum plates. In addition, it is used as a water-soluble binder in the composition of fireworks (pyrotechnics). Gum Arabic is also an important ingredient in shoe polish, makes newspaper print more cohesive, and can be used in making homemade incense cones. It is also used as a lickable adhesive, for example on postage stamps, envelopes, and cigarette papers. It really does help that Arabic Gum is not toxic!

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Diet Coke and Mentos Eruption.

Gum Arabic is not only edible but highly nutritious. During the time of the gum harvest, the denizens of the desert are said to live almost entirely on it, and it has been proved that 6 oz is sufficient to support an adult for 24 hours. It is rumored that the Bushman Hottentots have been known in times of scarcity to support themselves on it for days. In addition, the food industry has been using it as a demulcent, stabilizer and flavour fixative, for years. It is an important ingredient in chocolates (M&Ms, etc.), and “hard” gummy candies such as gumdrops and marshmallows. It is also used as an emulsifier and a thickening agent in icing, fillings, chewing gum and other confectionery treats. More generally, it gives body and texture to processed food products. Even wine makers have used Gum Arabic as a wine fining agent.

Probably the most interesting use for Gum Arabic is as part of soft drink syrups. It binds the sugar to the drink and avoids it from crystallizing on the bottom. Because Gum Arabic also reduces the surface tension of liquids, it is usually responsible for increased foaming in carbonated beverages. This can be exploited in the Diet Coke and Mentos Eruption, where a Mentos mint is thrown into a bottle of Diet Coke (or Pepsi) which causes the beverage to spray out of its container.


References

Dobelis, I.N., ed. 1086. Magic and Medicine of Plants. Pleasantville, NY: Reader’s Digest Association, Inc.

Duke, J.A. 1985. Handbook of Medicinal Herbs. Boca Raton, FL: CRC Press.

Greive, M. 1931. A Modern Herbal. New York: Dover Publications.

Leung AY, Foster S. 1980. Encyclopedia of Common Natural Ingredients Used in Food, Drugs, and Cosmetics. New York, NY: J. Wiley and Sons.

Meyer, J.E. 1934. The Herbalist . Hammond, IN: Hammond Book Co.

Wren, R.C. 1907 (1985). Potter’s New Cyclopaedia of Botanical Drugs and Preparations. Essex: The C.W. Daniel Company Limited.


To cite this post : Monica Ann Walker Vadillo, “Gum Arabic: History and Uses”, From the Herb Garret (blog on oldoperatingtheatre.com), December 11th, 2016. [On line] http://oldoperatingtheatre.com/gum-arabic-history-and-uses


monicaMonica Ann Walker Vadillo has a Ph.D. in the History of Art and an insatiable curiosity for history in all its forms. She is currently the digital manager and social media strategist at the Old Operating Theatre Museum and Herb Garret.