Packaging and storage—
Preserve in tight containers.
Solubility and reaction—
Dissolve 1 g in 2 mL of water; the resulting solution flows readily and is acid to litmus.
Botanic characteristics—
Acacia—
Spheroidal tears up to 32 mm in diameter or in angular fragments of white to yellowish white color. Is translucent or somewhat opaque from the presence of numerous minute fissures; very brittle, the fractured surface glassy and occasionally iridescent. Is almost odorless and produces a mucilaginous sensation on the tongue.
Flake Acacia—
White to yellowish white, thin flakes, appearing under the microscope as colorless, striated fragments.
Powdered Acacia—
White to yellowish white, angular microscopic fragments with only traces of starch or vegetable tissues present.
Granular Acacia—
White to pale yellowish white, fine granules. Under the microscope it appears as colorless, glassy, irregularly angular fragments up to 100 µm in thickness, some of which exhibit parallel linear streaks.
Spray-dried Acacia—
White to off-white compacted microscopic fragments or whole spheres.
Identification—
To 10 mL of a cold solution (1 in 50) add 0.2 mL of
diluted lead subacetate TS: a flocculent, or curdy, white precipitate is formed immediately.
Water, Method III 
921
—
Dry it at 105
for 5 hours: it loses not more than 15.0% of its weight. For unground Acacia, crush it in a mortar until it passes through a No. 40 sieve, and mix the ground material before weighing the test specimen.
Insoluble residue—
Dissolve 5.0 g of powdered or finely ground Acacia in about 100 mL of water in a 250-mL conical flask, add 10 mL of 3 N hydrochloric acid, and boil gently for 15 minutes. Filter by suction, while hot, through a tared filtering crucible, wash thoroughly with hot water, dry at 105
for 1 hour, and weigh. The weight of the residue thus obtained does not exceed 50 mg.
Starch or dextrin—
Boil a solution (1 in 50), cool, and add
iodine TS: no bluish or reddish color is produced.
Tannin-bearing gums—
To 10 mL of a solution (1 in 50) add 0.1 mL of
ferric chloride TS: no blackish coloration or blackish precipitate is produced.
