Nomenclature
CAS number: 9000-36-6
Gum karaya; kadaya; katilo; kullo; kuteera; sterculia; Indian tragacanth; mucara.
Description and references
The dried exudate of the tree Sterculia
urens Roxb., Sterculiaceae, found in India, especially
in the Gujerat region and in the central provinces: Toothaker, The Soluble Gums (Philadelphia, 1921); Mantell, The Water-Soluble Gums (New York, 1947).
Constituents and structure: Hirst, Dunstan, J. Chem. Soc. 1953, 2332. Structure is a
partially acetylated polysaccharide containing about 8% acetyl groups
and about 37% uronic acid residues. Reviews: F. Smith,
R. Montgomery, The Chemistry of Plant Gums
and Mucilages (Reinhold, New York, 1959); Goldstein, Alter,
in Industrial Gums, R. L. Whistler,
Ed. (Academic Press, New York, 2nd ed., 1973) pp 273-287.
Properties
Finely ground white powder, faint odor of acetic
acid. Acid to litmus. Absorbs water rapidly to form viscous mucilages
at low concs. Viscosity decreases on addn of acid or alkali. Color
of the soln lightens in acidic media and darkens in alkaline soln
due to the presence of tannins. Gum karaya loses viscosity forming
ability when stored in the dry state, the loss being greater for a
powdered material than for the crude gum. Cold storage inhibits this
degradation.Note
Karaya gum occurring in broken irregular
pieces having a somewhat crystalline appearance has been referred
to commercially as ‘crystal’ gum.Use
As denture adhesive; as binder in paper manuf; as
stabilizer, thickener, texturizer, emulsifier in foods; as thickening
agent for dyes in textile industry. A substitute for gum tragacanth.
Therapeutic Category
Cathartic.