Gum acacia

Gum arabic, also known as acacia gum, arabic gum, gum acacia, acacia, Senegal gum and Indian gum, and by other names, is a natural gum consisting of the hardened sap of various species of the acacia tree. Gum arabic is collected from acacia species, predominantly Acacia senegal and Vachellia (Acacia) seyal. 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 species, but may originate from Combretum, Albizia or some other genus. The gum is harvested commercially from wild trees, mostly in Sudan (80%) and throughout the Sahel, from Senegal to Somalia—though it is historically cultivated in Arabia and West Asia. Gum arabic is a complex mixture of glycoproteins and polysaccharides predominantly consisting of arabinose and galactose. It is soluble in water, edible, and used primarily in the food industry as a stabilizer, with EU E number E414. Gum arabic is a key ingredient in traditional lithography and is used in printing, paint production, glue, cosmetics and various industrial applications, including viscosity control in inks and in textile industries, though less expensive materials compete with it for many of these roles. While gum arabic is now produced throughout the African Sahel, it is still harvested and used in the Middle East. Gum arabic was defined by the 31st Codex Committee for Food Additives, held at The Hague from 19–23 March 1999, as the dried exudate from the trunks and branches of Acacia senegal or Vachellia (Acacia) seyal in the family Fabaceae (Leguminosae).:4 A 2017 safety re-evaluation by the Panel on Food Additives and Nutrient Sources of the European Food Safety Authority (EFSA) said that 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 species. 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, and 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 and 'hard' gummy candies such as gumdrops, marshmallows, and M&M's chocolate candies. For artists, it is the traditional binder in watercolor paint, 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, emulsifying agent, and a suspending 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 stabilizer, emulsifier 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 crystallizing and provide a smooth texture. Gum arabic is a soluble dietary fibre, a complex polysaccharide, primarily indigestible to both humans and animals. It is considered non-toxic and safe for human consumption. There is indication of harmless flatulence in some people taking large doses of 30g 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). There is no regulatory or scientific consensus about its caloric value; an upper limit of 2 kcal/g was set for rats, but this is not valid for humans. The US FDA initially set a value of 4 kcal/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.