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Introduction
E483 is an emulsifier produced by the esterification of tartaric acid with stearyl alcohol (a long-chain fatty alcohol). Unlike most other emulsifiers (which are glycerol-based or sugar-based), stearyl tartrate is an ester of an alcohol (stearyl) rather than a glyceride. The molecule contains a tartaric acid diester with two stearyl chains, making it highly lipophilic with an HLB value of approximately 2-3. E483 is primarily used in bakery products as a dough conditioner and in cake mixes to improve texture. It is also used as a texturizer in some margarines and spreads. However, E483 is not widely used today, having been largely replaced by more effective emulsifiers like E472e (DATEM) and E481/E482. It remains approved in the EU but is rarely found in modern food products. It is not approved in the USA (no FDA regulation).
CAS Number
1337-33-3 (stearyl tartrate, diester). Also 57741-17-0 (distearly tartrate).
Synonyms
Stearyl tartrate, Distearyl tartrate, Tartaric acid distearyl ester, Stearyl tartaric acid ester, E483.
Topic Headings
1. Chemical structure and properties (detailed paragraph form)
Stearyl tartrate is a diester formed from one molecule of tartaric acid and two molecules of stearyl alcohol (octadecanol, C18H37OH). Tartaric acid has two carboxyl groups and two hydroxyl groups (it is a dihydroxy dicarboxylic acid). In the esterification reaction, the two carboxyl groups react with two stearyl alcohol molecules, forming two ester bonds. The hydroxyl groups on tartaric acid remain free, providing a small polar region on an otherwise very lipophilic molecule. The resulting molecular weight is approximately 655 g/mol. The two long stearyl chains (each 18 carbons) make the molecule highly compatible with fats and oils, while the tartaric acid core provides mild surface activity. Unlike glycerol-based emulsifiers, stearyl tartrate does not have a glycerol backbone; its structure is more rigid. This rigidity results in a relatively high melting point (65-75°C) and poor dispersibility in water. The HLB value is very low (2-3), meaning it is almost insoluble in water and functions only in fat-continuous systems. Stearyl tartrate is also used as a food-grade wax and can form liquid crystals in combination with water.
2. Physical and chemical properties (list form)
• Appearance — White to off-white waxy solid, flakes, or powder.
• Odor — Very faint, characteristic fatty odor.
• Melting point — 65-75°C (higher than most food emulsifiers).
• Solubility — Soluble in fats and oils (especially above 70°C); insoluble in water; slightly soluble in hot ethanol; insoluble in cold ethanol and propylene glycol.
• HLB value — 2-3 (extremely lipophilic; only suitable for water-in-oil emulsions).
• Acid value — Maximum 10 mg KOH/g (low, indicating high ester purity).
• Saponification value — 160-180 mg KOH/g (lower than glycerol-based esters due to higher molecular weight).
• Iodine value — Typically <2 (from stearyl alcohol, which is fully saturated).
• Hydroxyl value — 50-80 mg KOH/g (from the two free hydroxyl groups on tartaric acid).
• Tartaric acid content — 20-25% (by weight).
• Stearyl alcohol content — 70-75%.
• Melting behavior — Sharp melting point (unlike glycerides which melt over a range); recrystallizes slowly.
• Density — Approximately 0.95-0.98 g/cm³ at 70°C.
3. Manufacturing process (paragraph form)
E483 is produced by direct esterification of tartaric acid with stearyl alcohol (octadecanol). The reaction is carried out at 180-220°C under vacuum (to remove water) for 4-8 hours. A catalyst such as p-toluenesulfonic acid or stannous octoate (0.1-0.5%) is typically used to accelerate the reaction. Excess stearyl alcohol (5-10% molar excess) is added to drive the reaction toward diester formation, minimizing monoester byproduct. After the reaction reaches the desired degree of esterification (typically >95% diester), the mixture is cooled to 100°C and neutralized (to remove or inactivate the catalyst). Excess stearyl alcohol is removed by steam distillation or wiped-film evaporation under vacuum. The product is then flaked or powdered. Quality control parameters include free tartaric acid (<1%), free stearyl alcohol (<5%), monoester content (<5%), and acid value (<10 mg KOH/g). The product is typically packaged in lined paper bags or plastic containers. Shelf life is 12-24 months under dry, cool conditions.
4. Applications (limited, historical, and current) (list form)
• Bread dough conditioning — 0.2-0.4% (flour basis) improves dough stability and gas retention; increases loaf volume by 10-15% (less effective than modern emulsifiers like E472e or E481).
• Cake mixes — 0.3-0.5% improves batter aeration and crumb texture; gives fine, uniform crumb structure (used before E475 and E477 became available).
• Margarine and spreads — 0.1-0.3% stabilizes water-in-oil emulsion; reduces spattering during frying; improves spreadability.
• Chocolate and confectionery coatings — 0.1-0.2% reduces viscosity (similar to E476 but less effective); improves gloss.
• Wax coatings for fruits and vegetables — 0.5-2.0% in edible wax formulations; provides gloss and moisture barrier; allowed in some jurisdictions for citrus and apples.
• Release agents for baking pans — 0.5-1.0% in oil-based sprays; provides non-stick properties.
• Pharmaceutical and cosmetic applications (non-food) — Used as a tablet lubricant and emulsifier in creams and lotions.
5. Reasons for limited use today (paragraph form)
Despite being approved in the EU, E483 is rarely found in modern food products for several reasons. First, its performance is inferior to newer emulsifiers. For bread volume increase, E472e (DATEM) gives 30-40% improvement compared to 10-15% for E483. For cake texture, E475 and E477 give finer crumb and better volume. Second, E483 has a very high melting point (65-75°C), which makes it difficult to incorporate into doughs and batters — it must be melted separately and added at a high temperature, which is inconvenient for manufacturers. Third, E483 has poor water dispersibility; it tends to form lumps when added to aqueous systems. Fourth, the raw material (stearyl alcohol) is more expensive than the fatty acids used for other emulsifiers. Fifth, consumer awareness of additive numbers has led manufacturers to prefer "clean label" alternatives or more familiar emulsifiers (E471, lecithin). Sixth, some studies in the 1970s raised safety concerns (see below), which damaged its reputation even though later studies were negative. Today, E483 is primarily used in specialty industrial applications (wax coatings, release agents) rather than in retail foods. It is sometimes found in commercial bakery mixes as a minor component of proprietary emulsifier blends.
6. Safety and regulatory status (paragraph form)
JECFA evaluated stearyl tartrate in 1974 and established an ADI of 0-30 mg/kg body weight. The evaluation was based on limited toxicological data, including a 90-day rat study showing no adverse effects at 1% of the diet. No long-term carcinogenicity studies were available at the time. In 1980, a study reported that high doses (5% of diet) caused kidney damage in rats, but this was not confirmed in later studies. EFSA re-evaluated E483 in 2015 and concluded that the available data are insufficient to set a new ADI. EFSA noted that no recent toxicological studies exist and that stearyl tartrate is rarely used in foods (estimated intake is negligible). EU maximum levels: 10 g/kg in bread and fine bakery wares, 5 g/kg in cake mixes, 5 g/kg in margarine (though actual use is far below these levels). E483 is not approved in the USA — it is not listed in 21 CFR as a direct food additive, nor is it GRAS. It is also not approved in Japan, Canada, Australia, or New Zealand. In the EU, E483 remains approved but is rarely used; it appears on ingredient lists of very few products (mainly some commercial bakery mixes and specialty margarines). For safety, individuals should not consume large quantities of foods containing E483, but typical exposure is negligible. No allergic reactions to E483 have been reported. Given its declining use, E483 is likely to be removed from the EU approved list in future revisions of food additive regulations.
7. Analytical methods for detection (list form)
• Thin layer chromatography (TLC) — Silica gel plate with hexane:ethyl acetate (8:2) as mobile phase; Rf value approximately 0.5; visualization with sulfuric acid spray and charring.
• Gas chromatography (GC) — After hydrolysis and derivatization (stearyl alcohol as free alcohol or trimethylsilyl derivative; tartaric acid as dimethyl ester).
• High performance liquid chromatography (HPLC) — Reverse-phase C18 column with acetonitrile:water gradient and refractive index or evaporative light scattering detection.
• Infrared spectroscopy (FTIR) — Characteristic peaks: carbonyl ester at 1735 cm⁻¹, O-H (free hydroxyls on tartaric acid) at 3400-3500 cm⁻¹, C-H at 2850-2950 cm⁻¹.
• Melting point determination — Sharp melting point (65-75°C) helps distinguish from other emulsifiers.
• Hydroxyl value — Titration after acetylation; indicates presence of free hydroxyl groups (two per molecule).
• Tartaric acid content — Colorimetric method (metavanadate reaction) or enzymatic method (tartrate dehydrogenase).
