Gum arabic

Gum arabic (gum acacia, gum sudani, Senegal gum and by other names) is a tree gum exuded by two species of Acacia sensu lato: Senegalia senegal, and Vachellia seyal. However, the term "gum arabic" does not indicate a particular botanical source. The gum is harvested commercially from wild trees, mostly in Sudan (about 70% of the global supply) and throughout the Sahel, from Senegal to Somalia. The name "gum Arabic" (al-samgh al-'arabi) was used in the Middle East at least as early as the 9th century. Gum arabic first found its way to Europe via Arabic ports and retained its name of origin.

Gum arabic is a complex mixture of glycoproteins and polysaccharides, predominantly polymers of arabinose and galactose. It is soluble in water, edible, and used primarily in the food industry and soft drink industry as a stabilizer, with E number E414 (I414 in the US). Gum arabic is a key ingredient in traditional lithography and is used in printing, paints, glues, cosmetics, and various industrial applications, including viscosity control in inks and in textile industries.

Gum arabic was defined by the 31st Codex Committee for Food Additives, held at The Hague from 19 to 23 March 1999, as the dried exudate from the trunks and branches of Acacia senegal or Vachellia (Acacia) seyal in the family Fabaceae (Leguminosae). A 2017 safety re-evaluation by the Panel on Food Additives and Nutrient Sources of the European Food Safety Authority (EFSA) said that although the above definition holds true for most internationally traded samples, the term "gum arabic" does not indicate a particular botanical source; in a few cases, so‐called "gum arabic" may not even have been collected from Acacia (in the broad sense) species, instead coming from e.g. Combretum or Albizia.

Gum arabic is a rich source of dietary fibers, and, in addition to its widespread use in food and pharmaceutical industries as a safe thickener, emulsifier, and stabilizer, it also possesses a broad range of health benefits that have been proven through in vitro and in vivo studies. Gum arabic is not degraded in the stomach, but fermented in the large intestine into a number of short chain fatty acids. It is regarded as a prebiotic that enhances the growth and proliferation of beneficial intestinal microbiota; therefore its intake is associated with many healthful effects. These health benefits include:

Gum arabic's mixture of polysaccharides and glycoproteins gives it the properties of a glue and binder that is edible by humans. Other substances have replaced it where toxicity is not an issue, as the proportions of chemicals in gum arabic vary widely and make it unpredictable. It remains an important ingredient in soft drink syrup and "hard" gummy candies such as gumdrops, marshmallows, and M&M's chocolate candies. For artists, it is the traditional binder in watercolor paint and in photography for gum printing, and it is used as a binder in pyrotechnic compositions. Pharmaceutical drugs and cosmetics also use the gum as a binder, emulsifier, and suspending agent or viscosity-increasing agent. Wine makers have used gum arabic as a wine fining agent.

It is an important ingredient in shoe polish, 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. Lithographic printers employ it to keep the non-image areas of the plate receptive to water. This treatment also helps to stop oxidation of aluminium printing plates in the interval between processing of the plate and its use on a printing press.

Gum arabic is used in the food industry as a stabiliser, emulsifying agent, and thickening agent in icing, fillings, soft candy, chewing gum, and other confectionery, and to bind the sweeteners and flavorings in soft drinks. A solution of sugar and gum arabic in water, gomme syrup, is sometimes used in cocktails to prevent the sugar from crystallising and provide a smooth texture.

Gum arabic is a complex polysaccharide and soluble dietary fibre that is generally recognized as safe for human consumption. An indication of harmless flatulence occurs in some people taking large doses of 30 g (1 oz) or more per day. It is not degraded in the intestine, but fermented in the colon under the influence of microorganisms; it is a prebiotic (as distinct from a probiotic). No regulatory or scientific consensus has been reached about its caloric value; an upper limit of 2 kcal/g (8.4 kJ/g) was set for rats, but this is invalid for humans. The US FDA initially set a value of 4 kcal/g (17 kJ/g) for food labelling, but in Europe no value was assigned for soluble dietary fibre. A 1998 review concluded that "based on present scientific knowledge, only an arbitrary value can be used for regulatory purposes". In 2008, the FDA sent a letter of no objection in response to an application to reduce the rated caloric value of gum arabic to 1.7 kcal/g (7.1 kJ/g).