What is E1516?

Complete guide to understanding E1516 (Glycerol Monoacetate/Monoacetin) in your food

The Quick Answer

E1516 is glycerol monoacetate (also called monoacetin or acetin)—a synthetic ester created by acetylation of glycerol with just ONE acetate group (leaving two hydroxyl groups intact). It’s a colorless, oily liquid used in food as a solvent for flavorings, flavor carrier, and texture modifier.

It’s used in food primarily to dissolve and distribute flavorings evenly—serving as a solvent/carrier for flavor compounds and other additives. E1516 is the most hydrophilic (water-loving) of the three glycerol acetate esters (E1516, E1517, E1518) because it retains the most unacetylated hydroxyl groups.

E1516 is recognized as safe by regulatory authorities. It’s less commonly used than E1517 (diacetate) or E1518 (triacetate), but serves specialized applications where maximum hygroscopicity and solvent properties are balanced.

What Exactly Is It?

E1516 is glycerol monoacetate (C₅H₁₀O₄), a synthetic ester created by partial acetylation of glycerol—attaching ONE acetate group to glycerol’s three hydroxyl groups (leaving two hydroxyl intact). It’s a colorless, oily, viscous liquid with a faint odor.

Think of it as glycerol with only one of its three “arms” wrapped in an acetate coat. This minimal modification creates a compound that’s much more hydrophilic and water-soluble than the diacetate (E1517) or triacetate (E1518), but less oleophilic (fat-soluble).

Key characteristic: The two unacetylated hydroxyl groups make monoacetin extremely hygroscopic (water-absorbing) and hydrophilic, while the single acetate group provides just enough lipophilicity to dissolve certain flavoring compounds. This unique balance makes it specialized for flavor-carrying applications.

Chemical composition:

• Molecular formula: C₅H₁₀O₄
• IUPAC name: 2,3-Dihydroxypropyl acetate (also 1,3-dihydroxypropyl acetate as isomer)
• CAS Number: 26446-35-5
• Molecular weight: 134.13 g/mol
• Density: 1.2 g/cm³
• Melting point: −43°C (very low—remains liquid)
• Boiling point: 282-283°C (very high)
• EC Number: 247-704-6

How it’s made:

E1516 is produced by partial acetylation of glycerol with acetic acid or acetic anhydride:

• Basic process: Glycerol (C₃H₈O₃) + 1 Acetic acid (CH₃COOH) → Glycerol monoacetate (C₅H₁₀O₄) + Water (H₂O)
• Isomeric mixture: The reaction produces mixture of 1-monoacetin and 2-monoacetin regioisomers
• Typical composition: Commercial monoacetin typically contains ~40% monoacetin, ~50% diacetate, ~18% triacetate (mixture of glycerol acetates)
• Control: Reaction carefully controlled to limit acetylation to single group
• Glycerol source: Can be petroleum-derived or vegetable-derived

Important note: Commercial “monoacetin” (E1516) is typically a mixture of mono-, di-, and triacetin rather than pure monoacetin. The primary component is monoacetin, but the mixture provides a range of hydrophilicity levels.

Where You’ll Find It

E1516 appears in a specialized range of food applications:

• Flavorings and flavor compounds (PRIMARY USE) – as solvent/carrier for flavor molecules
• Beverages and soft drinks – flavor distribution
• Baked goods – flavor carrier in flour mixtures
• Confectionery – limited use in candies requiring specific solvent properties
• Spice extracts – solvent for spice flavor compounds
• Beverage powders – flavor carrier in instant drink mixes
• Flavor concentrates – primary vehicle for distributing aromatic compounds

Regulatory use scope: EU Authorization—E1516 authorized as a solvent/carrier for food additives (particularly flavorings). FDA—recognized as safe for food use.

Primary food application: E1516 is essentially exclusively used as a solvent within flavor compounds and flavoring systems rather than as a standalone ingredient. It rarely appears directly labeled on consumer product labels.

Why Do Food Companies Use It?

E1516’s primary function is serving as a solvent and carrier specifically for flavoring compounds requiring high water-solubility and hygroscopicity.

Food manufacturers use monoacetin for specialized advantages:

• Solvent for flavorings: Dissolves and carries flavor compounds; enables even distribution
• Hygroscopic properties: Extremely hydrophilic; retains water and moisture
• Flavor carrier: Particularly useful for water-soluble flavor components
• Water solubility: Superior water solubility compared to di- or triacetin
• Flavor stabilization: Maintains flavor compound stability
• Polarity balance: Unique balance between hydrophilic and lipophilic character
• Processing efficiency: Enables incorporation of hydrophilic flavor components
• Cost efficiency: Effective as solvent at very low concentrations
• Regulatory universality: Approved for use as flavor carrier

Unique advantage in flavorings: E1516 is particularly valuable when flavor systems need to incorporate both water-soluble and slightly fat-soluble components. Its high water content and hygroscopicity make it ideal for aqueous flavor systems.

Is It Safe?

E1516 is safe at approved food use levels and has been approved by regulatory authorities.

Regulatory approval:

• FDA status: Recognized as safe; similar glycerol esters have GRAS status
• EU authorized: Approved as food additive E1516 for use as solvent/carrier
• JECFA recognized: Recognized as safe food additive
• International approval: Approved by regulatory bodies worldwide

Safety profile:

• No acute toxicity: No documented toxicity at food use levels
• No chronic toxicity: Long-term exposure at approved levels shows no harm
• No adverse effects: No documented adverse health effects
• No carcinogenicity: No evidence of cancer-causing potential
• No reproductive effects: Safe for pregnancy and breastfeeding
• No genotoxicity: No evidence of genetic damage
• Metabolism: Metabolized to glycerol and acetic acid (normal diet components)
• No bioaccumulation: Does not accumulate in tissues
• Long history of use: Decades of food and flavor industry use
• Similar safety to E1517/E1518: Similar or better safety profile than related compounds
• Flavor industry standard: Long-established use as flavor solvent with no documented issues

E1516 vs E1517 vs E1518: Acetate Comparison

Selection criteria: E1516 chosen for maximum water-solubility and flavor-carrying; E1517 for balanced properties; E1518 for strong plasticizing (chewing gum). E1516 most specialized, least commonly encountered.

Natural vs Synthetic Version

E1516 is synthetically produced but derived from natural-origin components:

Source and production:

• Glycerol source: Petroleum-derived or vegetable-derived (biodiesel byproduct, food processing)
• Acetic acid source: Petroleum-derived or fermentation-derived (vinegar fermentation)
• Synthesis: Chemical acetylation of glycerol
• Final product: Chemically identical regardless of source

Vegetarian/vegan/dietary status:

• Vegan: Yes—no animal products in synthesis
• Vegetarian: Yes
• Kosher: Yes
• Halal: Yes
• Gluten-free: Yes
• Dairy-free: Yes

Natural Alternatives

Want to avoid E1516 or looking for alternative solvent/carriers for flavorings?

Some alternatives include:

• Ethanol (E1510) – Alcohol solvent; most common flavor carrier
• Glycerin (E422) – Natural humectant and solvent
• Water – Direct solvent for water-soluble flavorings
• E1517 (Glycerol diacetate) – More balanced solvent properties
• E1518 (Glycerol triacetate) – For less water-soluble flavors
• Propylene glycol (E1520) – Synthetic solvent
• Gum arabic – Natural flavor encapsulant
• Direct incorporation: Adding flavorings without additional solvent (less efficient)

The Bottom Line

E1516 (glycerol monoacetate/monoacetin) is a specialized solvent and flavor carrier used almost exclusively within flavoring compounds—serving to dissolve and distribute flavor molecules evenly throughout food products.

It’s approved by regulatory authorities worldwide as a safe food additive.

Key advantages: E1516 is safe at food use levels. EU authorization and FDA recognition indicate regulatory confidence. No documented adverse effects. Metabolized to natural dietary components. Extremely specialized application as flavor solvent. Decades of established use in flavor industry.

For consumers: E1516 is safe when encountered in food products (though it rarely appears directly labeled). It’s a “hidden” ingredient component of flavor compounds. While synthetic, it’s approved by major regulatory authorities.

Unique specialization: E1516 is the most specialized of all three glycerol acetates—it’s essentially exclusively used as a flavor solvent for water-soluble flavor components. It’s not used for plasticizing (unlike E1517 and E1518) or as a standalone ingredient.

Rarity on labels: E1516 is extremely rarely encountered as a directly labeled ingredient because it functions only as a component of flavoring compounds, making it essentially invisible to consumers despite its ubiquitous use in the flavor industry.