Gum tragacanth

Description

An exudate from several species of shrubs of the genus Astragalus (especially Astragalus gummifer) found in the dry regions of Iran, Iraq, Syria, and Turkey. Gum tragacanth consists of a complex mixture of acidic polysaccharides containing galacturonic acid, Galactose, fucose, Xylose, and Arabinose. Tragacanth gum is available in the form of dull white, translucent plates (fiori) or as a yellowish powder (biondo). A soluble fraction, tragacanthin, dissolves when added to water, whereas an insoluble fraction, bassorin (60-70% by wt.) swells to a gel-like state. A solution of gum tragacanth is prepared by wetting the powder with alcohol, then adding water and shaking. Aqueous solutions are slightly acidic with a pH of 5-6. Gum tragacanth is used for textile sizing and printing, pastel crayon production, leather curing, and furniture polishes.

Synonyms and Related Terms

goma de tragacanto (Esp.); gomma adragante (It); gomma tragacante (It); olibanum; tragacanth; gum dragon; gomme adragante; Smyrna tragacanth; Anatolian tragacanth; Persian tragacanth; gum elect; fiori; biondo

FTIR

Risks

• Combustible.
• Inhalation and skin contact may cause allergies.
• Fisher Scientific: MSDS

Physical and Chemical Properties

Water swellable after wetting with ethanol. Soluble in alkali and hydrogen peroxide. Insoluble in ethanol.

CAS	9000-65-1
Density	1.25-1.384 g/ml

Resources and Citations

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• G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 822

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• Wikipedia: http://en.wikipedia.org/wiki/Tragacanth (Accessed Jan. 25, 2006)

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• Website address 1 Comment: "Violin Varnish Glossary" at www.violins.on.ca/luthier.vargloss.html