Modied Starch

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition
Issued and maintained by the United States Pharmacopeial Convention (USP)
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1 DEFINITION 

Modied Starch is Starch modied by chemical means. Food Starch may be acid-modied, bleached, oxidized, esteried, etheried, or treated enzymatically to change its functional properties (21 CFR 172.892). 

2 IDENTIFICATION 

2.1 A. 

Corn starch: Polygonal, rounded, or spheroidal granules up to 35 µm in diameter and usually having a circular or several-rayed central cleft Tapioca starch: Spherical granules with one truncated side, typically 5–35 µm in diameter and usually having a circular or several-rayed central cleft 

Potato starch: Irregularly shaped, ovoid, or pear-shaped granules, usually 30–100 µm in size but occasionally exceeding 100 µm; or rounded, 10–35 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 10–60 µm in diameter. The central hilum and striations are visible or barely visible. 

2.2 B. 

Sodium hydroxide solution: 2% (w/w) 

Sample: 0.6 g 

Analysis: Transfer the Sample 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 the Sodium hydroxide solution, cap, and shake vigorously for 1 min to create a smooth mixture. Evaluate within 1 min. Acceptance criteria: The nal solution is translucent to opaque with a uid consistency. A yellow tint of the nal solution is acceptable.

2.3 C.

A water slurry of the Modied Starch is colored orange-red to deep blue by iodine TS. 

3 IMPURITIES 

3.1 Residue on Ignition 〈281〉 

Sample: 2.0 ± 0.1 g 

Analysis: Proceed as directed in the chapter. 

Acceptance criteria: NMT 1.5% 

Change to read: 

3.2 Iron 〈241〉, Procedures, Procedure 1 (CN 1-Jun-2023) 

Test preparation: 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 ask, and mix. Dilute 25 mL of this solution with water to 47 ± 1 mL. 

Analysis: Proceed as directed in the chapter. 

Acceptance criteria: NMT 20 ppm 

3.3 Limit of Sulfur Dioxide 

Sample: 20.0 ± 0.1 g 

Analysis: Mix the Sample with 200 mL of 5% alcohol until a smooth suspension is obtained, and vacuum-lter through paper (Whatman No.1 or equivalent). To 100 mL of the ltrate add 3 mL of starch TS, and titrate with 0.01 N iodine VS to the rst permanent blue color. Acceptance criteria: NMT 1.7 mL of 0.01 N iodine VS is consumed, which corresponds to NMT 50 ppm of sulfur dioxide being found. 

3.4 Oxidizing Substances 

Sample: 4.0 g 

Titrimetric system 

Mode: Direct titration 

Titrant: 0.002 N sodium thiosulfate VS 

Blank: 30.0 mL of water, accurately measured 

Endpoint detection: Visual 

Analysis: Transfer the Sample to a glass-stoppered, 125-mL conical ask, and add 50.0 mL of water. Insert the stopper, and swirl for 5 min. 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 ask. Add 1 mL of glacial acetic acid and 0.5–1.0 g of potassium iodide. Insert the stopper, swirl, and allow to stand for 25–30 min in the dark. Add 1 mL of starch TS, and titrate with Titrant 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. 

Acceptance criteria: NMT 12.6 mL of 0.002 N sodium thiosulfate is required (180 ppm, calculated as H₂O₂), which corresponds to NMT 0.018% of oxidizing substances 

4 SPECIFIC TESTS 

4.1 Microbial Enumeration Tests 〈61〉 andTests for Specified Microorganisms 〈62〉:

The total aerobic microbial count does not exceed 103 cfu/g, and the total combined molds and yeasts count does not exceed 102 cfu/g. It meets the requirements of the tests for absence of Salmonella species and Escherichia coli. 

4.2 pH 〈791〉 

Sample: 20.0 ± 0.1 g 

Analysis: Transfer the Sample 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 5 min, and determine the pH to the nearest 0.1 unit. 

Acceptance criteria: 3.0–9.0 

4.3 Loss on Drying 〈731〉 

Analysis: Dry a sample at 120° for 4 h. Acceptance criteria 

Corn starch and Wheat starch: NMT 15.0% Tapioca starch: NMT 18.0% 

Potato starch: NMT 21.0% 

5 ADDITIONAL REQUIREMENTS 

Packaging and Storage: Preserve in well-closed containers. No storage requirements specied.