What is E1520?

Complete guide to understanding E1520 (Propylene Glycol) in your food

The Quick Answer

E1520 is propylene glycol (also called propane-1,2-diol or 1,2-propanediol)—a synthetic liquid alcohol used in food as a humectant (moisture retainer), solvent for flavorings and colorants, emulsifier, and stabilizer.

It’s used in food primarily to retain moisture, dissolve and distribute flavorings and food colorings evenly, stabilize emulsions, extend shelf life, and improve texture—found in baked goods, desserts, beverages, sauces, candies, and chewing gum.

E1520 is FDA GRAS approved and EFSA authorized with an established ADI of 0-25 mg/kg body weight (set 1973, reconfirmed 2018). It’s completely different from ethylene glycol (toxic antifreeze) and is safe for food use at regulatory levels.

What Exactly Is It?

E1520 is propylene glycol (C₃H₈O₂), a synthetic organic compound classified as a diol (contains two hydroxyl groups). It’s a thick, colorless, nearly odorless liquid with a slightly sweet taste.

Propylene glycol is fundamentally different from ethylene glycol (toxic antifreeze). While both are glycols used for freeze-point depression, propylene glycol is explicitly safe for food and cosmetic use, whereas ethylene glycol is poisonous and strictly prohibited in food applications.

Key distinction: The hydroxyl groups (-OH) on propylene glycol make it hydrophilic (water-loving), allowing it to absorb and retain moisture—the primary reason it’s used as a humectant in food.

Chemical composition:

• Molecular formula: C₃H₈O₂ (also written as CH₃CH(OH)CH₂OH)
• IUPAC name: Propane-1,2-diol
• CAS Number: 57-55-6
• Molecular weight: 76.10 g/mol
• Density: 1.04 g/cm³
• Melting point: -60°C
• Boiling point: 187°C
• Structure: Has two hydroxyl (-OH) groups, making it a diol

How it’s made:

E1520 is produced using three primary methods:

• Method 1 – Propylene oxide hydration (most common for food-grade): Propylene oxide (derived from petroleum) is reacted with water, with or without catalyst, producing propylene glycol. This is the dominant commercial method.
• Method 2 – Glycerin hydrogenolysis (bio-based): Glycerin (commonly vegetable-derived, a byproduct of biodiesel production) is reacted with hydrogen in the presence of catalyst, producing propylene glycol. This method creates “bio-based” propylene glycol.
• Method 3 – Chlorination hydrolysis: Propylene is reacted with chlorinated water to form 1-chloro-2-propanol, then hydrolyzed using sodium carbonate solution to produce propylene glycol.

Important note: The final food-grade propylene glycol contains approximately 20% propane-1,2-diol, 1.5% dipropylene glycol, and small amounts of other polypropylene glycols. Further purification produces USP/EP grade (99.5%+ pure).

Where You’ll Find It

E1520 appears in an extensive range of food and beverage products:

• Baked goods (very common) – moisture retention, texture improvement, prevents staling
• Cakes and pastries – moisture, softness, shelf life
• Ice cream and frozen desserts – anti-crystallization, smooth texture, moisture
• Puddings and desserts – texture, moisture, stability
• Candy and confectionery (up to 24%) – texture, moisture, sweetness enhancer
• Salad dressings – emulsifier, stability
• Sauces and condiments – stability, texture
• Beverages (including non-alcoholic beer and wine) – carrier for flavorings/colorings
• Chewing gum (very common) – moisture retention, texture
• Flavorings and essences (rum, vanilla, lemon) – solvent for flavor compounds
• Food colorings and dyes – solvent and carrier
• Vitamins and supplements – carrier, solvent
• Icing and frostings – texture, moisture
• Soups and broths – moisture, stability
• Margarines – emulsifier, stability

Regulatory use scope: FDA approves E1520 for multiple applications with maximum levels varying: seasonings/flavorings 97%, confections/frostings 24%, nuts 5%, frozen dairy 2.5%, others 2.0%. EFSA authorizes use as carrier in “colours, emulsifiers and antioxidants,” enzymes, flavorings and nutrients.

E1520 is extremely common in processed foods, though consumers often don’t recognize it because it performs functional roles (moisture, solvent) rather than obvious flavor or appearance changes.

Why Do Food Companies Use It?

E1520’s primary function is moisture retention and serving as a solvent for other additives.

Food manufacturers use propylene glycol for multiple strategic advantages:

• Humectant (moisture retention): Absorbs and retains water; prevents drying out of baked goods, cakes, pastries
• Shelf life extension: Slows moisture loss; extends freshness and storage life
• Solvent and carrier: Dissolves and distributes flavorings, food colorings, vitamins, and antioxidants evenly throughout product
• Emulsifier: Stabilizes emulsions; prevents separation in dressings, sauces, margarines
• Stabilizer: Improves texture and consistency; prevents crystallization
• Thickener: Increases viscosity; improves mouthfeel
• Texture improver: Enhances softness and palatability
• Anti-caking agent: Prevents caking in powdered products
• De-foaming agent: Reduces foam in beverages and other products
• Antimicrobial: At 15-30% concentration, inhibits microbial growth (bactericide effect)
• Anti-crystallization: Prevents sugar/ice crystallization in frozen products
• Processing efficiency: Reduces production time; improves manufacturing efficiency
• Taste masking: Can mask unpleasant flavors of other ingredients
• Flavor carrier: Enhances flavor distribution; improves flavor perception
• Cost efficiency: Inexpensive; effective at low concentrations
• Regulatory universality: Approved worldwide with recognized safety status

Unique advantage in baking: E1520 is particularly valuable in bread and pastry production because it reduces staling by maintaining moisture content—extending shelf life without added preservatives.

Is It Safe?

E1520 is safe at approved food use levels and extensively approved by major regulatory authorities.

Regulatory approval:

• FDA approved: Generally Recognized As Safe (GRAS) for use as anticaking agent, dough strengthener, emulsifier, humectant, solvent, stabilizer, thickener, texturizer
• EFSA authorized: Approved as food additive E1520 for use as carrier in colours, emulsifiers, antioxidants, enzymes, flavorings, and nutrients
• JECFA approved: ADI 0-25 mg/kg body weight (set 1973, reconfirmed 2018)
• 2018 EFSA Re-evaluation: Comprehensive safety assessment concluded no reason to revise the ADI of 25 mg/kg bw/day
• Food Standards Australia New Zealand: Approved
• International approval: Approved by virtually all regulatory bodies worldwide

2018 EFSA Safety Review Findings:

The European Food Safety Authority conducted comprehensive re-evaluation after studies of:

• Metabolism • Genotoxicity (genetic damage) • Chronic and subchronic toxicity • Reproductive and developmental toxicity • Allergenicity

Result: Concluded there was no reason to revise the ADI of 25 mg/kg body weight per day. No safety concerns identified.

Safety profile:

• ADI status: 0-25 mg/kg body weight per day (established safety limit)
• No acute toxicity: No documented toxicity at food use levels
• No chronic toxicity: Long-term use at approved levels shows no harm
• No genotoxicity: No evidence of genetic damage; multiple studies confirm safety
• No carcinogenicity: No evidence of cancer-causing potential
• No reproductive effects: Safe for pregnancy and breastfeeding
• No allergenicity: EFSA did not classify as allergen; no allergy potential reported
• Metabolism: Completely metabolized and excreted by body
• No bioaccumulation: Does not accumulate in tissues
• Decades of safe use: Used in cosmetics, pharmaceuticals, and food for decades
• Non-toxic antifreeze: Used as safer alternative to ethylene glycol (toxic) in industrial applications, demonstrating safety profile
• Pharmaceutical use: Approved and used in pharmaceutical preparations (IV, oral, topical), indicating high safety standard

Natural vs Synthetic Version

E1520 is synthetically produced but can be derived from natural feedstocks:

Source and production:

• Petroleum-based route: Propylene oxide (from petroleum) hydrated to propylene glycol (most common industrial method)
• Bio-based route: Glycerin (vegetable-derived, from biodiesel production) hydrogenolyzed to propylene glycol (emerging “green” method)
• Final product: Chemically identical regardless of source

Perceived “naturalness”: E1520 from the bio-based route (glycerin from biodiesel) could be considered “natural-origin” or “bio-based,” but from petroleum feedstocks it’s fully synthetic. However, both are approved as equally safe by FDA/EFSA.

Vegetarian/vegan/dietary status:

• Vegan: Yes—when derived from vegetable glycerin (bio-based route) or purely synthetic. No animal products involved either way.
• Vegetarian: Yes
• Kosher: Yes
• Halal: Yes
• Gluten-free: Yes
• Dairy-free: Yes

Natural Alternatives

Want to avoid E1520 or looking for alternative humectants and solvents?

Some alternatives include:

• Glycerin (E422) – Natural humectant; similar properties; common alternative
• Sorbitol (E420) – Sugar alcohol; humectant; sweetener
• Xylitol (E967) – Sugar alcohol; humectant; sweetener
• Honey – Natural humectant; retains moisture
• Corn syrup – Natural humectant
• Molasses – Natural humectant
• Water – Basic humectant (less effective)
• Vegetable oils – For emulsification (different properties)
• Natural gums (xanthan, guar) – Stabilizers/thickeners (different properties)
• Simply accept drying: Reduce shelf life; use fresher products more quickly

Comparison to Glycerin (E422)

E1520 vs E422 (Glycerin): Both are humectants with similar moisture-retaining properties. Glycerin is more “natural” (vegetable-derived in most cases). Propylene glycol is more synthetically manufactured. Both are FDA GRAS approved. Glycerin is slightly more expensive; propylene glycol is cost-efficient. Both are safe.

The Bottom Line

E1520 (propylene glycol) is a synthetic humectant and solvent used to retain moisture, dissolve flavorings/colorants, stabilize emulsions, and extend shelf life in baked goods, desserts, beverages, sauces, and numerous processed foods.

It’s approved by the FDA, EFSA, JECFA, and virtually all regulatory bodies worldwide with an established ADI of 0-25 mg/kg body weight (set 1973, reconfirmed 2018).

Key advantages: E1520 is safe at approved food use levels. FDA GRAS approval and EFSA authorization indicate regulatory confidence. Comprehensive 2018 re-evaluation reconfirmed safety. No documented adverse effects at normal food concentrations. Completely different and safer than toxic ethylene glycol.

Common misconception: E1520 is NOT antifreeze. It’s a food additive that CAN be used in antifreeze applications because it’s safe (unlike ethylene glycol). This distinction is important.

For consumers: E1520 is safe when encountered in food products. While synthetic, it’s explicitly approved for food use by all major regulatory authorities. If preferring natural alternatives, glycerin (E422) offers similar properties from vegetable sources.

Primary applications: E1520 is invaluable in baking (moisture retention, shelf life extension), candy/confectionery (texture, moisture), beverage flavorings (solvent for flavor distribution), and frozen desserts (anti-crystallization).

Regulatory confidence: The established ADI and comprehensive 2018 re-evaluation demonstrate that regulatory authorities are confident in E1520’s safety at approved use levels.