Packaging and storage—
Preserve in well-closed containers.
Botanic characteristics—
Microscopic—
Granules similar in appearance to the starch from which the Dextrin has been prepared, except that when prepared from cornstarch many of the granules show concentric striations and when prepared from potato starch concentric striations are not clearly visible, the hilum is frequently bicleft, and a small proportion of the granules are distorted.
Identification—
A:
Suspend about 1 g in 20 mL of water, and add a few drops of
iodine TS: a blue to reddish brown color results.
B:
Dextrin is very soluble in boiling water, forming a mucilaginous solution (difference from starch).
Loss on drying 
731
—
Dry it at a pressure not exceeding 100 mm of mercury at 120
for 4 hours: it loses not more than 13.0% of its weight.
Acidity—
Add 10.0 g to 100 mL of 70 percent alcohol, previously neutralized to phenolphthalein, shake for 1 hour, filter, and titrate 50 mL of the filtrate with 0.10 N sodium hydroxide: not more than 3.0 mL is required.
Chloride 221—
Dissolve 3.0 g in 75 mL of boiling water, cool, dilute with water to 75 mL, and filter if necessary. To 25 mL of this solution add 2 mL of nitric acid and 1 mL of
silver nitrate TS: any turbidity produced is not greater than that of a control containing 2.8 mL of 0.020 N hydrochloric acid (0.2%).
Protein:
not more than 1.0%, when determined as directed under
Nitrogen Determination 461, using a 10-g specimen instead of 1 g, and 60 mL of sulfuric acid instead of 20 mL, and multiplying the percentage of nitrogen found by 6.25.
Reducing sugars—
To a quantity of Dextrin equivalent to 2.0 g on the dried basis add 100 mL of water, shake for 30 minutes, dilute with water to 200 mL, accurately measured, and filter. To 10.0 mL of
alkaline cupric tartrate TS add 20.0 mL of the filtrate, mix, and heat on a hot plate adjusted to bring the solution to a boil in 3 minutes. Boil for 2 minutes, and cool quickly. Add 5 mL of potassium iodide solution (3 in 10) and 10 mL of 2 N sulfuric acid, mix, and titrate immediately with 0.1 N sodium thiosulfate VS, using
starch TS, added towards the end of the titration, as indicator. Repeat the procedure beginning with “To 10 mL of,” using, in place of the filtrate, 20 mL of a 1 in 1000 solution of anhydrous dextrose, accurately prepared. Perform a blank titration. (
VB 
VU) is not greater than (
VB VS), in which
VB,
VU, and
VS are the number of mL of 0.1 N sodium thiosulfate consumed in the titrations of the blank, the Dextrin and the dextrose, respectively (10%, calculated as dextrose, C
6H
12O
6).
