Table 1.
Specifications for GEWR (E 445) according to Commission Regulation (EU) No 231/2012 and the JECFA (2013)
| Commission Regulation (EU) No 231/2012 E 445 | JECFA (2018) INS No. 445(iii) | |
|---|---|---|
| Synonyms | Ester gum | |
| Definition | A complex mixture of tri‐ and diglycerol esters of resin acids from wood rosin. The rosin is obtained by the solvent extraction of aged pine stumps followed by a liquid–liquid solvent refining process. Excluded from these specifications are substances derived from gum rosin, and exudate of living pine trees, and substances derived from tall oil rosin, a by‐product of kraft (paper) pulp processing. The final product is composed of ~ 90% resin acids and 10% neutrals (non‐acidic compounds). The resin acid fraction is a complex mixture of isomeric diterpenoid monocarboxylic acids having the empirical molecular formula of C20H30O2, chiefly abietic acid. The substance is purified by steam stripping or by counter current steam distillation | Glycerol ester of wood rosin is a complex mixture of glycerol di‐ and triesters of resin acids from wood rosin, with a residual fraction of glycerol monoesters. In addition, neutrals (non‐acidic saponifiable and unsaponifiable substances) and residual free resin acids are present. Wood rosin is obtained by the solvent extraction of aged pine stumps, followed by a liquid–liquid solvent refining process. Refined wood rosin is composed of 90% resin acids and 10% neutrals. The resin–acid fraction is a complex mixture of isomeric diterpenoid monocarboxylic acids having the typical empirical formula C20H30O2, of which the main components are dehydroabietic and abietic acid. GEWR is produced by esterifying the resin acids with food grade glycerol. The product is then purified by steam stripping or by countercurrent steam distillation. These specifications do not cover substances derived from gum rosin, an exudate of living pine trees, and substances derived from tall oil rosin, a by‐product of kraft (paper) pulp processing |
| Description | Hard, yellow to pale, amber‐coloured solid | Hard, yellow to pale, amber‐coloured solid |
| Identification | ||
| Solubility | Insoluble in water, soluble in acetone | Insoluble in water, soluble in acetone |
| Infrared absorption spectrum | Characteristic of the compound | The infrared spectrum of a thin film of the sample (potassium bromide disc) corresponds with the typical infrared spectrum below |
| Sulfur test | – |
Negative Weigh 40–50 mg of sample into a test tube and add 1–2 drops of a 20% (w/v) solution of sodium formate. Place a strip of lead acetate test paper over the mouth of the test tube. Heat the tube until fumes are formed that contact the test paper. Continue heating for 2–5 min. The formation of a black spot of lead sulfide indicates the presence of sulfur‐containing compounds. (Detection Limit: 50 mg/kg sulfur) |
| Gas chromatography of resin alcohols and glycerol | – | Passes test |
| Purity | ||
| Specific gravity of solution | [d]20 25 not less than 0,935 when determined in a 50% solution in d‐limonene (97%, boiling point 175,5–176°C, d20 4: 0,84) | d20 25: Not less than 0.935 (50% solution in d‐limonene) |
| Ring and ball softening range | Between 82°C and 90°C | Not less than 82 |
| Acid value | Not less than 3 and not more than 9 | Between 3 and 9 |
| Hydroxyl value | Not less than 15 and not more than 45 | – |
| Arsenic | Not more than 3 mg/kg | – |
| Lead | Not more than 2 mg/kg | Not more than 1 mg/kg |
| Mercury | Not more than 1 mg/kg | – |
| Cadmium | Not more than 1 mg/kg | – |
| Test for absence of tall oil rosin (sulfur test) | When sulfur‐containing organic compounds are heated in the presence of sodium formate, the sulfur is converted to hydrogen sulfide which can readily be detected by the use of lead acetate paper. A positive test indicates the use of tall oil rosin instead of wood rosin | – |
AAS: atomic absorption spectroscopy; ICP‐AES: inductively coupled plasma atomic emission spectroscopy.