Table 3.
Specifications for sodium, potassium and calcium salts of fatty acids (E 470a) according to Commission Regulation (EU) No 231/2012 and JECFA (2006), and for magnesium salts of fatty acids (E 470b) according to Commission Regulation (EU) No 231/2012 and magnesium distearate (JECFA, 2015)
| Sodium, potassium and calcium salts of fatty acids (E 470a) | Magnesium salts of fatty acids (E 470b) | Salts of fatty acids (INS No 470) | Magnesium distearate, dibasic magnesium stearate, INS No 470(iii) | |
|---|---|---|---|---|
| Commission Regulation (EU) No 231/2012 | Commission Regulation (EU) No 231/2012 | JECFA (2006) | JECFA (2015) | |
| Definition | Sodium, potassium and calcium salts of fatty acids occurring in food oils and fats, these salts being obtained either from edible fats and oils or from distilled food fatty acids | Magnesium salts of fatty acids occurring in food oils and fats, these salts being obtained either from edible fats and oils or from distilled food fatty acids |
These products consist of calcium, potassium or sodium salts of commercial myristic, oleic, palmitic, stearic, acids or mixtures of these acids from edible fats and oils. The article of commerce can be further specified by:
|
Magnesium stearate is a mixture of magnesium salts of fatty acids obtained from edible fats and oils. The product consists mainly of magnesium stearate and palmitate in varying proportions. It is manufactured by one of the two following processes: (a) direct process wherein fatty acids are directly reacted with a magnesium source, such as magnesium oxide to form magnesium salts of the fatty acids; (b) indirect process where a sodium soap is produced by the reaction of fatty acids with sodium hydroxide in water and the product is precipitated by adding magnesium salts to the soap |
| Assay | Content on the anhydrous basis not less than 95% (105°C till a constant weight) | Content on the anhydrous basis not less than 95% (105°C till a constant weight) | Not less than 95% total fatty acid salts, dry weight basis | |
| Description | White or creamy white light powders, flakes or semi‐solids | White or creamy white light powders, flakes or semi‐solids | Hard, white or faintly yellowish, somewhat glossy and crystalline solids or semi‐solids or white or yellowish‐white powder | |
| Identification | ||||
| Solubility |
Sodium and potassium salts: soluble in water and ethanol Calcium salts: insoluble in water, ethanol and ether |
Insoluble in water, partially soluble in ethanol and ether | Potassium and sodium salts are soluble in water and ethanol; calcium salts are insoluble in water, ethanol and ether | Practically insoluble in water |
| Test for cations | Passes test | – | Heat 1 g of the sample with a mixture of 25 mL of water and 5 mL of hydrochloric acid. Fatty acids are liberated, floating as a solid or oil layer on the surface which is soluble in hexane. After cooling, aqueous layer is decanted and evaporated to dryness. Dissolve the residue in water and test for the appropriate cation | |
| Test for magnesium | – | Passes test | – | Using the Method of Assay, identify presence of magnesium in the sample |
| Test for fatty acids | Passes test | Passes test | Using the Method of Assay, identify the individual fatty sample. The fatty acid(s) in primary abundance should conform to those declared on the label of the product | |
| Purity | ||||
| Sodium | Not less than 9% and not more than 14% expressed as Na2O | – | – | |
| Potassium | Not less than 13% and not more than 21.5% expressed as K2O | – | – | |
| Calcium | Not less than 8.5% and not more than 13% expressed as CaO | – | – | |
| Magnesium | – | Not less than 6.5% and not more than 11% expressed as MgO | – | Not less than 4.0% and not more than 5.0%, on dried basis |
| Unsaponifiable matter | Not more than 2% | Not more than 2% | Not more than 2% | Not more than 2% |
| Free fatty acids | Not more than 3% estimated as oleic acid | Not more than 3% estimated as oleic acid |
Not more than 3% Measure free fatty acids as directed in the method Free Fatty Acids. Compute free fatty acid content using an equivalence factor (e) equal to 1/10th the molecular weight of the salt |
Not less than 40.0% stearic acid in the fatty acid fraction; and not less than 90.0% as the sum of stearic acid and palmitic acid in the fatty acid fraction |
| Arsenic | Not more than 3 mg/kg | Not more than 3 mg/kg | – | |
| Lead | Not more than 2 mg/kg | Not more than 2 mg/kg |
Not more than 2 mg/kg Determine using an atomic absorption technique appropriate to the specified level. The selection of sample size and method of sample preparation may be based on the principles of the method described in Volume 4, ‘Instrumental Methods’ |
Not more than 2 mg/kg |
| Mercury | Not more than 1 mg/kg | Not more than 1 mg/kg | – | |
| Cadmium | Not more than 1 mg/kg | Not more than 1 mg/kg | – | Not more than 1 mg/kg |
| Nickel | Not more than 3 mg/kg | |||
| Free alkali | Not more than 0.1% expressed as NaOH | Not more than 0.1% expressed as MgO | – | |
| Matter insoluble in alcohol | Not more than 0.2% (sodium and potassium salts only) | – | – | |