law://eu/reg/2012/231/anx_1__grp_181@2026-11-13| E 424 CURDLAN | |
| Synonyms | (1 → 3)-ß-d-Glucan |
| Definition | Curdlan is a high molecular weight polysaccharide consisting of β-1,3-linked glucose units, produced by pure-culture fermentation from a non-pathogenic and non-toxicogenic Rhizobium radiobacter biovar 1 strain NTK-u. Curdlan consists of β-(1,3)-linked glucose residues and has the unusual property of forming an elastic gel upon heating in its aqueous suspension. Crude curdlan is purified through several steps, which include alkaline dissolution and crystallisation in methanol. The crystallised solution is subjected to purification steps, i.e. centrifugation, washing and centrifugation once more. Then the product is dried, milled and sieved to obtain the final product. |
| CAS number | 54724-00-4 |
| Chemical formula | H•(C6H10O5)n•OH |
| Average molecular weight | Not less than 1,4 × 106 Da |
| Assay (calculated as anhydrous glucose) | Not less than 80 % |
| Description | Odourless or almost odourless, white to nearly white powder |
| Identification | |
| Solubility | Insoluble in water and ethanol |
| Solubility in alkali | Passes testSuspend 0,2 g of the sample in 5 mL of water, add 1 mL of 3 N sodium hydroxide and shake. The sample dissolves. |
| Gel formation | Heat a 2 % aqueous suspension of the sample in a boiling water bath for 10 min and cool. A firm gel forms. |
| Precipitate formation with cupric tartrate | Passes test |
| pH | Between 6,0-7,5 (1 % aqueous suspension) |
| Gel strength | Not less than 600 g/cm2 |
| Purity | |
| Loss on drying | Not more than 10 % |
| Residue on ignition | Not more than 6 % |
| Sulfated ash | Not more than 6 % |
| Nitrogen | Not more than 0,3 % |
| Arsenic | Not more than 0,05 mg/kg |
| Lead | Not more than 0,2 mg/kg |
| Methanol | Not more than 10 mg/kg |
| Microbiological criteria | |
| Total plate count | Not more than 1000 CFU/g |
| Coliforms | Absent in 1 g |
| Escherichia coli | Absent in 1 g |
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