Packaging and storage—
Preserve in well-closed containers. No storage requirements specified.
Identification—
A:
Examine Tapioca Starch under a microscope, using not less than 20× magnification and using glycerin as the mounting agent: it appears as spherical granules with one truncated side, typically having a 5- to 35-µm diameter and having circular or several-rayed central clefts.
B:
Suspend 1 g of Tapioca Starch in 50 mL of water, boil for 1 minute, and cool: a thin, cloudy mucilage is formed.
C:
To 1 mL of the mucilage obtained in Identification test B add 0.05 mL of iodine and potassium iodide TS 2: an orange-red to dark blue color is produced, which disappears on heating.
Microbial limits 
61
—
It meets the requirements of the test for absence of
Escherichia coli. The total aerobic microbial count does not exceed 1000 cfu per g, and the total combined molds and yeasts count does not exceed 100 cfu per g.
pH 791—
Weigh 20.0 ± 0.1 g of Tapioca Starch, transfer to a suitable nonmetallic container, and add 100 mL of water to obtain a slurry. Agitate continuously at a moderate rate for 5 minutes, then stop agitation, and immediately determine the pH: between 4.5 and 7.0.
Loss on drying 731—
Dry it at 130
for 90 minutes: it loses not more than 16.0% of its weight.
Iron 241:
0.002%, the
Test Preparation being prepared as follows. Shake 0.75 g of Tapioca Starch with 15 mL of 0.1 N hydrochloric acid, and filter. Use 10 mL of this solution as the
Test Preparation.
Limit of oxidizing substances—
Transfer 4.0 g of Tapioca Starch to a glass-stoppered, 125-mL conical flask, and add 50.0 mL of water. Insert the stopper, and swirl for 5 minutes. Decant into a glass-stoppered, 50-mL centrifuge tube, and centrifuge to clarify. Transfer 30.0 mL of the clear supernatant to a glass-stoppered, 125-mL conical flask. Add 1 mL of glacial acetic acid and 0.5 to 1.0 g of potassium iodide. Insert the stopper, swirl, and allow to stand for 25 to 30 minutes in the dark. Add 1 mL of starch TS, and titrate with 0.002 N sodium thiosulfate VS to the disappearance of the starch–iodide color. Perform a blank determination, and make any necessary correction (see
Titrimetry 541). Each mL of 0.002 N sodium thiosulfate VS is equivalent to 34 µg of oxidant, calculated as hydrogen peroxide. Not more than 1.4 mL of 0.002 N sodium thiosulfate VS is required: not more than 0.002% of oxidizing substances is found.
Limit of sulfur dioxide—
Mix 20 g of Tapioca Starch with 200 mL of water until a smooth suspension is obtained, and filter. To 100 mL of the clear filtrate add 3 mL of starch TS, and titrate with 0.01 N iodine solution VS to the first permanent blue color. Not more than 1.7 mL is consumed: not more than 0.005% of sulfur dioxide is found.
