E 460 (i) MICROCRISTALLINE CELLULOSE
Commission Directive 98/86/EC
Synonyms Cellulose gel
Definition Microcrystalline cellulose is purified, partally depolymerised cellulose
prepared by treating alpha-cellulose, obtained as a pulp from natural strains of fibrous plant material, with mineral acids. The degree of polymerisation is typically less than 400
Chemical name Cellulose
Einecs 232-674-9
Chemical formula (C6H10O5)n
Molecular weight About 36 000
Assay Not less than 97 % calculated as cellulose on the anhydrous basis
Description A fine white or almost white odourless powder
Identification
A. Solubility Insoluble in water, ethanol, ether and dilute mineral acids. Slightly soluble in sodium hydroxide solution
B. Colour reaction To 1 mg of the sample, add 1 ml of phosphoric acid and heat on a water bath for 30 minutes. Add 4 ml of a 1 in 4 solution of pyrocatechol in phosphoric acid and heat for 30 minutes, A red colour is produced
C. To be identified by IR spectroscopy
D. Suspension test Mix 30 g of the sample with 270 ml of water in a high-speed (12 000 rpm) power blender for 5 minutes. The resultant mixture will be either a free-following suspension or a heavy, lumpy suspension which flows poorly, if at all, settles only slightly and contains many trapped air bubbles. If a free-flowing suspension is obtained, transfer 100 ml into a 100-ml graduated cylinder and allow to stand for 1 hour. The solids settles and a supernatant liquid appears
Purity
Loss on drying Not more than 7 % (105 °C, 3 hours)
Water-soluble matter Not more than 0,24%
Sulphated ash Not more than 0,5 % determined at 800 ± 25 °C
pH of a 10 % suspension in water The pH of the supernatant liquid is between 5,0 and 7,5
Starch Not detectable
To 20 ml of the dispersion obtained in identification, test D, add a few drops of iodine solution and mix. No purplish to blue or blue colour should be produced
Particle size Not less than 5 µm (not more than 10 % of particles of less than 5 µm)
Carboxyl groups Not more than 1 %
Arsenic Not more than 3 mg/kg
Lead Not more than 5 mg/kg
Mercury Not more than 1 mg/kg
Cadmium Not more than 1 mg/kg
Heavy metals (as Pb) Not more than 10 mg/kg