Packaging and storage—
Preserve in well-closed containers. No storage requirements specified.
Identification—
A:
Corn starch:
polygonal, rounded, or spheroidal granules up to about 35 µm in diameter and usually having a circular or several-rayed central cleft.
Tapioca starch:
spherical granules with one truncated side, typically 5 to 35 µm in diameter and usually having a circular or several-rayed central cleft.
Potato starch:
irregularly shaped, ovoid, or pear-shaped granules, usually 30 to 100 µm in size but occasionally exceeding 100 µm; or rounded, 10 to 35 µm in size. There are occasional compound granules having two to four components. The ovoid and pear-shaped granules have an eccentric hilum, and the rounded granules have an accentric or slightly eccentric hilum. All granules show clearly visible concentric striations.
Wheat starch:
large and small granules, usually 10 to 60 µm in diameter. The central hilum and striations are visible or barely visible.
B:
Prepare a 2% (w/w) sodium hydroxide solution. Weigh 0.6 g of Modified Starch, and transfer to a 25-mL glass vial with a plastic cap. Add 9.4 g of water, cap, and shake vigorously to evenly disperse the starch. Add 10 g of 2% sodium hydroxide solution, cap, and shake vigorously for 1 minute to create a smooth mixture. Evaluate within 1 minute. The final solution is translucent to opaque with a fluid consistency. A yellow tint of the final solution is acceptable.
C:
A water slurry of the Modified Starch is colored orange-red to deep blue by iodine TS.
Microbial limits 
61
—
It meets the requirements of the tests for absence of
Salmonella species and
Escherichia coli. The total aerobic microbial count does not exceed 1000 cfu per g; the total combined molds and yeasts count does not exceed 100 cfu per g.
pH 791—
Weigh 20.0 ± 0.1 g of Modified Starch, transfer to a suitable nonmetallic container, and add 100 mL of water to obtain a slurry. Stir using a magnetic stirrer at a moderate rate for about 5 minutes, and determine the pH to the nearest 0.1 unit: between 3.0 and 9.0.
Loss on drying 731—
Dry it at 120
for 4 hours.
Corn starch and
Wheat starch: not more than 15.0%;
Tapioca starch: not more than 18.0%; and
Potato starch: not more than 21.0%.
Iron 241:
0.002%, the
Test Preparation being prepared as follows. Dissolve the residue obtained in the test for
Residue on ignition in 8 mL of hydrochloric acid with the aid of gentle heating. Dilute with water to 100 mL in a volumetric flask, and mix. Dilute 25 mL of this solution with water to 47 ± 1 mL.
Oxidizing substances—
Transfer 4.0 g to a glass-stoppered, 125-mL conical flask, and add 50.0 mL of water. Insert the stopper, and swirl for 5 minutes. Transfer to 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 g 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–iodine color. Perform a blank determination, and make any necessary correction. Each mL of 0.002 N sodium thiosulfate is equivalent to 34 µg of oxidant, calculated as hydrogen peroxide. Not more than 12.6 mL of 0.002 N sodium thiosulfate is required (180 µg per g, calculated as H2O2): not more than 0.018% of oxidizing substances is found.
Limit of sulfur dioxide—
Mix 20.0 ± 0.1 g of Modified Starch with 200 mL of 5% alcohol until a smooth suspension is obtained, and vacuum-filter through paper (Whatman No.1 or equivalent). To 100 mL of the filtrate add 3 mL of starch TS, and titrate with 0.10 N iodine to the first permanent blue color. Not more than 2.7 mL is consumed: not more than 0.005% of sulfur dioxide is found.
