| Synonyms | Tragacanth gum; Tragant |
| Definition | Tragacanth is a dried exudation obtained from the stems and branches of strains of Astragalus gummifer Labillardiere and other Asiatic species of Astragalus (family Leguminosae). It consists mainly of high molecular weight polysaccharides (galactoarabans and acidic polysaccharides) which, on hydrolysis, yield galacturonic acid, galactose, arabinose, xylose and fucose. Small amounts of rhamnose and of glucose (derived from traces of starch and/or cellulose) may also be present |
| Einecs | 232-252-5 |
| Chemical name | |
| Chemical formula | |
| Molecular weight | Approximately 800 000 |
| Assay | |
| Description | Unground Tragacanth gum occurs as flattened, lamellated, straight or curved fragments or as spirally twisted pieces 0,5-2,5 mm thick and up to 3 cm in length. It is white to pale yellow in colour but some pieces may have a red tinge. The pieces are horny in texture, with a short fracture. It is odourless and solutions have an insipid mucilaginous taste. Powdered tragacanth is white to pale yellow or pinkish brown (pale tan) in colour |
| Identification |
|---|
| Solubility | 1 g of the sample in 50 ml of water swells to form a smooth, stiff, opalescent mucilage; insoluble in ethanol and does not swell in 60 % (w/v) aqueous ethanol |
| Purity |
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| Test for Karaya gum | Negative. Boil 1 g with 20 ml of water until a mucilage is formed. Add 5 ml of hydrochloric acid and again boil the mixture for five minutes. No permanent pink or red colour develops |
| Loss on drying | Not more than 16 % (105 °C, 5 hours) |
| Total ash | Not more than 4 % |
| Acid insoluble ash | Not more than 0,5 % |
| Acid insoluble matter | Not more than 2 % |
| Arsenic | Not more than 3 mg/kg |
| Lead | Not more than 2 mg/kg |
| Mercury | Not more than 1 mg/kg |
| Cadmium | Not more than 1 mg/kg |
| Microbiological criteria |
|---|
| Salmonella spp. | Absent in 10 g |
| Escherichia coli | Absent in 5 g |
