COMMISSION REGULATION (EU) No 231/2012 of 9 March 2012
Synonyms
Sodium carboxymethyl cellulose, enzymatically hydrolysed
Definition
Enzymatically hydrolysed carboxymethylcellulose is obtained from carboxymethylcellulose by enzymatic digestion with a cellulase
produced by Trichoderma longibrachiatum (formerly T. reesei)
Einecs:
Chemical name: Carboxymethyl cellulose, sodium, partially enzymatically hydrolysed
Chemical formula: Sodium salts of polymers containing substituted anhydroglucose units with the general formula:
[C 6 H 7 O 2 (OH) x (OCH 2 COONa) y ] n where n is the degree of polymerisation
x = 1,50 to 2,80
y = 0,2 to 1,50
x + y = 3,0
(y = degree of substitution)
Molecular weight: 178,14 where y = 0,20. 282,18 where y = 1,50. Macromolecules: Not less than 800 (n about 4)
Assay: Not less than 99,5 %, including mono- and disaccharides, on the dried
Description
White or slightly yellowish or greyish, odourless, slightly hygroscopic granular or fibrous powder
Identification
Solubility: Soluble in water, insoluble in ethanol
Foam test: Vigorously shake a 0,1 % solution of the sample. No layer of foam appears. This test distinguishes sodium carboxymethyl cellulose, whether hydrolysed or not, from other cellulose ethers and from alginates and natural gums
Precipitate formation: To 5 ml of a 0,5 % solution of the sample add 5 ml of a 5 % solution of copper or aluminium sulphate. A precipitate appears. This test distinguishes sodium carboxymethyl cellulose, whether hydrolysed or not, from other cellulose ethers and from gelatine, carob bean gum and tragacanth gum
Colour reaction: Add 0,5 g of the powdered sample to 50 ml of water, while stirring to produce a uniform dispersion. Continue the stirring until a clear solution is produced. Dilute 1 ml of the solution with 1 ml of water in a small test tube. Add 5 drops of 1-naphthol TS. Incline the tube, and carefully introduce down the side of the tube 2 ml of sulphuric acid so that it forms a lower layer. A red-purple colour develops at the interface
Viscosity (60 % solids): Not less than 2 500 kgm – 1 s – 1 at 25 °C corresponding to an average molecule weight of 5 000 Da
pH: Not less than 6,0 and not more than 8,5 (1 % colloidal solution)
Purity
Loss on drying: Not more than 12 % (105 °C to constant weight)
Degree of substitution: Not less than 0,2 and not more than 1,5 carboxymethyl groups per anhydroglucose unit on the dried basis
Sodium chloride and sodium glycolate: Not more than 0,5 % singly or in combination
Residual enzyme activity: Passes test. No change in viscosity of test solution occurs, which indicates hydrolysis of the sodium carboxymethyl cellulose
Lead: Not more than 3 mg/kg