Acacia gum (gum arabic)

Abstract

Acacia gum (AG) is the dried gum of the stem and branches of acacia trees (family leguminosae) and various other acacia trees throughout the world and it is often referred to commercially as gum arabic. AG is a complex polysaccharide consisting mainly of calcium salts of polyarabic acid, but also contains magnesium and potassium ions. It is a high molecular weight polysaccharide molecule containing Dgalactopyranose, D-glucuronic acid, L-rhamnopyranose and L-arabofuranose. On hydrolysis, acacia yields hexoses, arabinose, galactose, rhamnose and glucuronic acid. AG is generally recognized as safe by the US FDA. It is widely used in the production of foods such as puddings, frostings, candy, beverages and chewing gum. It has demulcent properties and is often added to medicines for that purpose [1–4]. AG is a water soluble fermentable polysaccharide resistant to gut enzymes and thus can be described as a dietary fiber. The principle fermenter bacteria capable of using acacia as the only carbohydrate source are bacteriods and bifidobacterium. The proportion of these flora rise after acacia ingestion and return to initial levels after cessation of ingestion. AG is completely degraded in the colon [5]. The energy value of AG is 14.7 ± 0.5 kJ/g, lower than the energy value of starch 17.4 ± 0.4 kJ/g [6]. AG administered to men for 3 weeks has no effect on glucose tolerance, but decreases serum cholesterol [7].