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Prepared at the 44th JECFA (1995), published in FNP 52 Add 3 (1995) superseding specifications prepared at the 41st JECFA (1993), published in FNP 52 Add 2 (1993) |
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SYNONYMS |
INS No. 404 |
DEFINITION |
Calcium salt of alginic acid. |
C.A.S. number |
9005-35-0 |
Chemical formula |
(C6 H7 Ca1/2 O6)n |
Structural formula |
Structural formula from Phillips, Wedlock and Williams: Gums and Stabilizers for the Food Industry 5 (1990) by permission of Oxford University Press.
The number and sequence of the Mannuronate and Glucuronate residues shown above vary in the naturally occurring alginate. The associated water molecules are not hown. |
Formula weight |
Structural unit: 195.16 (theoretical), 219 (actual average) Macromolecule: 32,000 - 600,000 (typical average) |
Assay |
Not less than 18.0% and not more than 21.0% of carbon dioxide (CO2), equivalent to not less than 89.6% and not more than 104.5% of calcium alginate (C6H7Ca1/2 O6)n on the anhydrous basis. |
DESCRIPTION |
White to yellowish brown filamentous, grainy, granular and powdered forms |
FUNCTIONAL USES |
Stabilizer, thickener, gelling agent, emulsifier |
CHARACTERISTICS | |
IDENTIFICATION | |
Solubility |
Insoluble in water and ether; slightly soluble in ethanol; slowly soluble in solutions of sodium polyphosphate, sodium carbonate, and substances that combine with calcium ions. |
Precipitate formation with calcium chloride |
To a 0.5% solution of the sample in sodium hydroxide TS add one-fifth of its volume of a 2.5% solution of calcium chloride. A voluminous, gelatinous precipitate is formed. This test distinguishes ammonium alginate from gum arabic, sodium carboxymethyl cellulose, carrageenan, gelatin, gum ghatti, karaya gum, carob bean gum, methyl cellulose and tragacanth gum. |
Precipitate formation with ammonium sulfate |
To a 0.5% solution of the sample in sodium hydroxide TS add one-half of its volume of a saturated solution of ammonium sulfate. No precipitate is formed. This test distinguishes ammonium alginate from agar, sodium carboxymethyl cellulose, carrageenan, de-esterified pectin, gelatin, carob bean gum, methyl cellulose and starch. |
Colour reaction |
Passes test Moisten 1-5 mg of the sample with water, and add 1 ml of acid ferric sulfate TS. Within 5 min, a cherry-red colour develops that finally becomes deep purple. |
Test for calcium |
Passes test |
PURITY | |
Loss on drying |
Not more than 15% (105o, 4 h) |
Sulphated ash |
Not less than 5% on the dried basis |
Arsenic |
Not more than 28% and not more than 36% on the dried basis. |
Lead |
Not more than 5 mg/kg Prepare a sample solution as directed for organic compounds in the Limit Test, using 5 μg of lead ion (Pb) in the control |
Heavy metals |
Not more than 20 mg/kg Test 1 g of the sample as directed under the Limit Test (Method II) |
Microbiological criteria |
Total plate count: Not more than 5,000 colonies per gram. Initially prepare a 10-1 dilution by adding a 50 g sample to 450 ml of Butterfield’s phosphate buffered dilution water and homogenizing in a high speed blender. Yeasts and moulds: Not more than 500 colonies per gram Coliforms: Negative by test Salmonella: Negative by test |
METHOD OF ASSAY |
Proceed as directed under Carbon Dioxide Determination by Decarboxylation. Each ml of 0.25 N sodium hydroxide consumed is equivalent to 5.5 mg of carbon dioxide (CO2) or 27.38 mg of calcium alginate (equivalent weight 219) |