Microcrystalline cellulose

Prepared at the 49th JECFA (1997)
superseding specifications prepared at the 46th JECFA (1996),
published in FNP 52 Addendum 4 (1996)

SYNONYMS

Cellulose gel, INS No. 460

DEFINITION

Microcrystalline cellulose is a purified, partially depolymerized cellulose prepared by treating alpha-cellulose, obtained as a pulp from fibrous plant material, with mineral acids. The degree of polymerization is typically less than 400. Not more than 10% of the material has a particle size of less than 5 m m.

Chemical names

Cellulose

C.A.S. number

9004-34-6

Chemical formula

(C₆H₁₀O₅)_n

Assay

Not less than 97% of carbohydrate calculated as cellulose on the dried basis

DESCRIPTION

Fine, white or almost white, odourless, free flowing crystalline powder

FUNCTIONAL USES

Emulsifier, stabilizer, anticaking and dispersing agent

CHARACTERISTICS

IDENTIFICATION

Solubility

Insoluble in water, ethanol, ether and dilute mineral acids. Slightly soluble in sodium hydroxide solution

Infrared absorption

The infrared absorption spectrum of a potassium bromide dispersion of the sample corresponds to the infrared spectrum in the Appendix

PURITY

Loss on drying

Not more than 7.0% (105 °, 3h)

pH

5.0 - 7.5
Shake 5 g of the sample with 40 ml of water for 20 min and centrifuge. Use the supernatant for pH determination

Water soluble substances

Not more than 0.24%
See description under TESTS

Sulfated ash

Not more than 0.05%
Proceed as directed under the test for Ash (Sulfated Ash, Method I) using 2 g of the sample

Lead

Not more than 2 mg/kg
Prepare a sample solution as directed for organic compounds in the Limit Test and determine the lead content by atomic absorption spectrometry

Starch

Not detectable
See description under TESTS

TESTS

PURITY TESTS

Water soluble substances

Shake 5 g of the sample with approximately 80 ml of water for 10 min, filter through Whatman No. 42 or equivalent filter paper into a tared beaker, evaporate to dryness on a steam bath and dry at 105° for 1h. Cool, weigh and calculate as percentage.

Starch

Mix 30 g of the sample with 270 ml of water in a high-speed (18,000 rpm) blender for 5 min. Transfer 100 ml of the mixture to a 100-ml graduated cylinder, and allow to stand for 3h. A white opaque, bubble-free dispersion which does form a supernatant liquid at the surface, is obtained.
To 20 ml of this dispersion add a few drops of iodine TS, and mix. No purplish to blue or blue colour should be produced.

METHOD OF ASSAY

Transfer about 125 mg of the sample, accurately weighed, to a 300-ml Erlenmeyer flask, using about 25 ml of water. Add 50.0 ml of 0.5N potassium dichromate, mix, then carefully add 100 ml of sulfuric acid, and heat to boiling. Remove from heat, allow to stand at room temperature for 15 min, cool in a water bath, and transfer into a 250-ml volumetric flask. Dilute with water almost to volume, cool to 25 °, then dilute to volume with water, and mix. Titrate a 50.0-ml aliquot with 0.1N ferrous ammonium sulfate, using 2 or 3 drops of ortho-phenanthroline TS as the indicator, and record the volume required as S, in ml. Perform a blank determination, and record the volume of 0. IN ferrous ammonium sulfate required as B, in ml. Calculate the percentage of cellulose in the sample by the formula:

in which W is the weight of sample taken, in mg, corrected for Loss on Drying.

APPENDIX

Infrared spectrum: Microcrystalline cellulose

SYNONYMS	Cellulose gel, INS No. 460
DEFINITION	Microcrystalline cellulose is a purified, partially depolymerized cellulose prepared by treating alpha-cellulose, obtained as a pulp from fibrous plant material, with mineral acids. The degree of polymerization is typically less than 400. Not more than 10% of the material has a particle size of less than 5 m m.
Chemical names	Cellulose
C.A.S. number	9004-34-6
Chemical formula	(C₆H₁₀O₅)_n
Assay	Not less than 97% of carbohydrate calculated as cellulose on the dried basis
DESCRIPTION	Fine, white or almost white, odourless, free flowing crystalline powder
FUNCTIONAL USES	Emulsifier, stabilizer, anticaking and dispersing agent
CHARACTERISTICS
IDENTIFICATION
Solubility	Insoluble in water, ethanol, ether and dilute mineral acids. Slightly soluble in sodium hydroxide solution
Infrared absorption	The infrared absorption spectrum of a potassium bromide dispersion of the sample corresponds to the infrared spectrum in the Appendix
PURITY
Loss on drying	Not more than 7.0% (105 °, 3h)
pH	5.0 - 7.5 Shake 5 g of the sample with 40 ml of water for 20 min and centrifuge. Use the supernatant for pH determination
Water soluble substances
	Not more than 0.24% See description under TESTS
Sulfated ash	Not more than 0.05% Proceed as directed under the test for Ash (Sulfated Ash, Method I) using 2 g of the sample
Lead	Not more than 2 mg/kg Prepare a sample solution as directed for organic compounds in the Limit Test and determine the lead content by atomic absorption spectrometry
Starch	Not detectable See description under TESTS
TESTS
PURITY TESTS
Water soluble substances
	Shake 5 g of the sample with approximately 80 ml of water for 10 min, filter through Whatman No. 42 or equivalent filter paper into a tared beaker, evaporate to dryness on a steam bath and dry at 105° for 1h. Cool, weigh and calculate as percentage.
Starch	Mix 30 g of the sample with 270 ml of water in a high-speed (18,000 rpm) blender for 5 min. Transfer 100 ml of the mixture to a 100-ml graduated cylinder, and allow to stand for 3h. A white opaque, bubble-free dispersion which does form a supernatant liquid at the surface, is obtained. To 20 ml of this dispersion add a few drops of iodine TS, and mix. No purplish to blue or blue colour should be produced.
METHOD OF ASSAY	Transfer about 125 mg of the sample, accurately weighed, to a 300-ml Erlenmeyer flask, using about 25 ml of water. Add 50.0 ml of 0.5N potassium dichromate, mix, then carefully add 100 ml of sulfuric acid, and heat to boiling. Remove from heat, allow to stand at room temperature for 15 min, cool in a water bath, and transfer into a 250-ml volumetric flask. Dilute with water almost to volume, cool to 25 °, then dilute to volume with water, and mix. Titrate a 50.0-ml aliquot with 0.1N ferrous ammonium sulfate, using 2 or 3 drops of ortho-phenanthroline TS as the indicator, and record the volume required as S, in ml. Perform a blank determination, and record the volume of 0. IN ferrous ammonium sulfate required as B, in ml. Calculate the percentage of cellulose in the sample by the formula: in which W is the weight of sample taken, in mg, corrected for Loss on Drying.