CALCIUM SORBATE

Prepared at the 51st JECFA (1998), published in FNP 52 Add 6 (1998) superseding specifications prepared at the 17th JECFA (1973), published in FNP 4 (1978) and republished in FNP 52 (1992). Group ADI 0-25 mg/kg bw for sorbic acid and its calcium, potassium and sodium salts, expressed as sorbic acid, established at the 17th JECFA in 1973.

SYNONYMS

INS No. 203

DEFINITION

Chemical names

Calcium sorbate; calcium salt of trans, trans-2,4-hexadienoic acid.

C.A.S. number

7492-55-9

Chemical formula

C₁₂H₁₄CaO₄

Structural formula

Formula weight

262.32

Assay

Not less than 98% and not more than 102% after drying

DESCRIPTION

Fine white crystalline powder not showing any change in colour after heating at 105^o for 90 min

FUNCTIONAL USES

Preservative

CHARACTERISTICS

IDENTIFICATION

Solubility

Soluble in water; practically insoluble in ethanol.

Test for calcium

Passes test

Melting range of sorbic acid derived from the sample

132 - 135^o

Acidify a solution of the sample with dilute hydrochloric acid TS. Collect the precipitated sorbic acid on a filter paper, wash free of chloride with water and dry under vacuum over sulfuric acid.

Test for unsaturation

To 2 ml of a 1 in 10 solution of the sample, add a few drops of bromine TS. The colour of the bromine disappears.

PURITY

Loss on drying

Not more than 3% (over sulfuric acid in vacuum, 4h)

Fluoride

Not more than 10 mg/kg

Weigh 5 g of the sample to the nearest mg and proceed as directed in the Fluoride Limit Test (Method I or III)

Aldehydes

Not more than 0.1% (as formaldehyde)

Prepare a 0.3% solution of the sample, adjust the pH to 4 with 1N HCl and filter. To 5 ml of the filtrate add 2.5 ml of Schiff's reagent TS and allow to stand for 10-15 min. Compare the colour with that produced by 5 ml of a control solution containing 15 µg of formaldehyde instead of the sample. The colour of the test solution should not be more intense than that of the control solution.

Lead

Not more than 2 mg/kg

Prepare a sample solution as directed for organic compounds in the Limit Test and determine by atomic absorption spectroscopy.

METHOD OF ASSAY

Weigh to the nearest mg, 0.25 g of the dried sample. Dissolve in 35 ml of glacial acetic acid and 4 ml of acetic anhydride in a 250-ml glass-stoppered flask, warming to effect solution. Cool to room temperature, add 2 drops of crystal violet TS and titrate with 0.1 N perchloric acid in glacial acetic acid to a blue-green end point which persists for at least 30 sec. Perform a blank determination and make any necessary correction. Each ml of 0.1 N perchloric acid is equivalent to 13.12 mg of C₁₂H₁₄CaO₄.