STERCULIA GUM

SYNONYM: Indian tragacanth, Karaya gum

BIOLOGICAL SOURCE: It is the gummy exudation obtained from the blazes and incisions of Sterculia urens (Roxburgh) belonging to the family Sterculiaceae.

GEOGRAPHICAL SOURCE: India, Pakistan, Africa.

COLLECTION AND PREPARATION: Collection-from wild growing plants, twice a year before monsoon (April-May) and in September after the rainy season. Bark is removed from the stem of larger trees (a square foot of blazes) and smaller trees are incise .Gums are ooze out immediately in large quantities during first 24 hours and then slows down, but continues for several days. It is then sorted out foreign organic matters are removed (bark pieces, sand, soil etc) and graded according to colour and presence of foreign organic matter.  One tree can be tapped for about 5 times and about 1-5 kg /year average yield.

CHARACTERS: colourless (best quality) to pink to dark brown, translucent, irregular tears or vermiform pieces, odour- odour of vinegar, taste-mucilaginous ,insoluble in water, powdered gum swells in water.

CHEMICAL CONSTITUENTS: Hetero polysaccharides of sugars and uronic acids which on acid hydrolysis gives galactose, rhamnose, galacuronic acid, aldobionic acid and uronic acid of trisaccharide. It contains 8% of acetyl content and more than 37% of total acid content.

USES: Bulk laxative (due to its swelling properties), emulsifying agent, stabilizing and thickening agent, used as dental adhesive in dental treatment, used as food additive in ice pops, cheese spread, sherbets and ground meat products, also used in paper and textile industries.

SUBSTITUTES:  Sterculia. villosa (Roxburgh),Sterculia.tragacantha (Lindley)

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