Gum arabic is an exudate gum picked from Acacia trees growing in tropical arid regions (typically Acacia Senegal and Acacia Laetia).
The polysaccharide is branched with a main chain of (1-3) linked β-D-galactopyranosyl units with side chains of (1-3) β-D-galactopyranosyl units joined to it by (1-6) links. The side chains are 2-5 units in length.
Both the main chain and the side chains have attached units of α-L-arabinofuranosyl, α-L-rhamnopyranosyl, β-D-glucuronopyranosyl and 4-O-methyl-β-D-glucuronopyranosyl units.