Gum karaya is a vegetable gum produced as an exudate by trees of the genus sterculia. chemically, gum karaya is an acid polysaccharide composed of the sugars galactose, rhamnose and galacturonic acid. it is used as a thickener and emulsifier in foods, as a laxative, and as a denture adhesive. it is also used to adulterate gum tragacanth due to their similar physical characteristics.