Pregelatinized Modified Starch
» Pregelatinized Modified Starch is Modified Starch that has been chemically or mechanically processed, or both, to rupture all or part of the granules to produce a product that swells in cold water.
A: Prepare a 2% (w/w) sodium hydroxide solution. Weigh 0.6 g of Pregelatinized 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% NaOH 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.
B: An aqueous dispersion of Pregelatinized Modified Starch is colored orange-red to deep blue by iodine TS.
pH 791 Wet 10.0 ± 0.1 g of Pregelatinized Modified Starch with 10 mL of alcohol, then dilute with water to 300 mL to obtain an aqueous dispersion. Stir continuously at a moderate rate for 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: it loses not more than 15% of its weight.
Residue on ignition 281: not more than 1.5%, a test specimen of 2.0 ± 0.1 g being used.
Oxidizing substances To 5 g of Pregelatinized Modified Starch add 20 mL of a mixture of methanol and water (1:1), then add 1 mL of 6 N acetic acid, and stir until a homogeneous suspension is obtained. Add 0.5 mL of a freshly prepared saturated solution of potassium iodide, mix, and allow to stand for 5 minutes: no distinct blue, brown, or purple color is observed.
Limit of sulfur dioxide Mix 20.0 ± 0.1 g of Pregelatinized Modified Starch with 100 mL of 95 percent alcohol, and stir for several minutes to completely wet the starch. Slowly add 100 mL of water, and stir until a smooth suspension is obtained. Allow the starch mixture to set undisturbed until most of the starch has settled, and filter the aqueous portion through paper (Whatman No. 1 or equivalent). To 100 mL of the clear filtrate add 100 mL of water, and mix. Add 3 mL of starch TS, and titrate with 0.01 N iodine VS to the first permanent blue or purple color. Not more than 1.7 mL is consumed: not more than 0.005% of sulfur dioxide is found.
Other requirements It meets the requirements for Packaging and storage and in the tests for Microbial limits and Iron under Modified Starch.