**3.1.4.3 Gum karaya**

Gum karaya, also known as sterculia gum, is a branched acidic polysaccharide obtained from the exudates of the *Sterculia urens* tree of the Sterculiaceae family grown in India. The backbone chain is a rhamnogalacturonan consisting of α-(1→4)-linked D-galacturonic acid and α-(1→2)-linked-L-rhamnosyl residues. The side chain is made of (1→3)-linked β-Dglucuronic acid, or (1→2)-linked β-D-galactose on the galacturonic acid unit where one half of the rhamnose is substituted by (1→4) linked β-D-galactose.
