What is E363?

Complete guide to understanding E363 (Succinic Acid) in your food

The Quick Answer

E363 is succinic acid, a naturally occurring organic acid that plays a crucial role in energy production in all living cells.

It’s used in food primarily as an acidity regulator, flavor enhancer, preservative, and pH buffer—providing a mild sour and umami taste.

E363 is one of the most “natural” food additives available: it occurs naturally in fruits, vegetables, and wine, and is a normal intermediate metabolite in human cellular energy production (the citric acid cycle). This unique status means the body already recognizes and metabolizes it as a normal dietary component.

What Exactly Is It?

E363 is succinic acid (C₄H₆O₄), a small dicarboxylic organic acid with two carboxylic acid groups.

Succinic acid is one of the most “natural” additives because it plays a vital role in human metabolism. Every cell in your body produces succinic acid as part of the citric acid cycle (also called the Krebs cycle)—the fundamental energy-generation process in mitochondria. This means your body already recognizes, produces, and metabolizes succinic acid as a normal biological compound.

Chemical composition:

• Molecular formula: C₄H₆O₄
• IUPAC name: 1,4-Butanedioic acid
• Alternative names: Butanedioate, dioxysuccinic acid, amber acid
• CAS Number: 110-15-6
• Molecular weight: 118.09 g/mol
• Density: ~1.56 g/cm³

How it’s made:

Succinic acid is produced using two primary methods:

• Method 1 – Chemical synthesis (most common): Acetic acid is catalytically converted to succinic acid through chemical reactions. This is the dominant commercial route.
• Method 2 – Microbial fermentation: Glucose (from corn starch or other sugars) is fermented using specific bacteria (such as Actinobacillus succinogenes or engineered strains) to produce succinic acid directly. This method is increasingly popular for “green” or bio-based production.

Natural occurrence: Succinic acid naturally occurs in:

• All fruits (especially berries, apples)
• Most vegetables
• Wine and fermented foods
• Human tissues and metabolic pathways (produced continuously by mitochondria)

Where You’ll Find It

E363 appears in limited food applications:

• Flavored fermented milk products
• Soups and broths (maximum use 3,000-6,000 mg/kg)
• Flavored drinks in powder form for home preparation
• Desserts
• Dairy products and emulsions
• Some beverages and flavor enhancers
• Instant noodles (as flavoring agent)
• Candies (to enhance fruit flavor)
• Condiments and relishes (max 0.084% in FDA usage)
• Meat products (max 0.0061% in FDA usage)
• Baked goods (to improve leavening)
• Frozen foods (to improve stability)

Limited food use: E363 is notably less commonly used in food compared to other acidifiers like citric acid (E330) or malic acid (E296). Its use is restricted to specific applications where its particular properties are advantageous. The primary industrial applications for succinic acid are in chemical manufacturing (polymers, resins, solvents) rather than food.

Regulatory use levels (EFSA): Maximum use 3,000-6,000 mg/kg in approved food categories

Why Do Food Companies Use It?

E363’s primary function is pH buffering combined with flavor enhancement and preservation.

Food manufacturers use succinic acid for multiple strategic advantages:

• Acidity regulation: Controls and regulates pH in food products
• Buffering capacity: Strong buffering due to two carboxylic acid groups; resists pH changes
• Preservation: Antimicrobial properties; reduces microbial growth by >99.9% at concentrations as low as 0.1%
• Flavor enhancement: Provides mild sour taste and umami properties; enhances flavor complexity
• Taste improvement: Adds slightly sour and slightly salty taste profile
• Color stabilization: Antioxidant capacity prevents browning and color degradation
• Shelf life extension: Prevents oxidative spoilage and microbial growth
• Metabolic advantage: Body readily metabolizes it as normal biochemical intermediate
• Chelating properties: Can bind metal ions that cause turbidity or off-flavors
• Leavening assistance: Improves leavening action in baked goods
• Energy source: Acts as energy source in some applications (animal feed, supplements)
• Water solubility: Highly soluble (58 g/L); easy to incorporate into products
• Chemical stability: Stable at normal processing temperatures; doesn’t degrade
• Natural image: Naturally occurs in fruits and is normal metabolite—appeals to “clean label” consumers

Unique advantage in supplements: E363 is particularly valued in nutritional supplements for its role as a metabolic intermediate and energy-supporting compound, rather than just for flavor or preservation.

Is It Safe?

E363 is exceptionally safe, being a normal metabolite in human biochemistry.

Regulatory approval:

• FDA approved: Generally Recognized As Safe (GRAS); approved for use as flavor enhancer and pH control agent at levels not exceeding good manufacturing practice
• Approved applications (FDA): Condiments & relishes (max 0.084%), meat products (max 0.0061%)
• EFSA approved: Listed in Commission Regulation (EU) No 231/2012 as authorized food additive
• JECFA approved: ADI “not specified” (established at 6 mg/kg body weight previously in 1991)
• Food Standards Australia New Zealand: Approved with code number 363
• International approval: Approved by UN FAO and WHO

Safety profile:

• ADI: “Not specified” by JECFA—indicating no safety concerns
• Normal metabolite: Succinic acid is produced continuously by mitochondria in every cell
• No acute toxicity: No documented toxicity at food use levels
• No chronic toxicity: No documented chronic toxicity from food use
• No genotoxicity: No evidence of genetic damage
• No carcinogenicity: No evidence of cancer-causing potential
• No reproductive effects: Safe for pregnancy and breastfeeding
• Metabolism: Metabolized through the citric acid cycle (Krebs cycle)—the fundamental energy-generation pathway
• Energy metabolism: Used for ATP (cellular energy) production
• Biodegradable: Rapidly biodegradable in environment
• Antimicrobial data: Studies show >99.9% microbial reduction at 0.1% concentration
• No documented adverse effects: No widespread adverse effects documented from food use
• Manufacturer studies: Bioamber studies concluded food-grade material had no adverse effects and was safe under intended use conditions (FDA-approved 2015)

Unique safety advantage: Because succinic acid is a normal metabolic intermediate in the citric acid cycle, the body already has all necessary machinery to safely handle and utilize it. This makes it exceptionally safe compared to synthetic additives the body doesn’t naturally encounter.

Natural vs Synthetic Version

E363 is naturally occurring but industrially manufactured:

Source and production:

• Starting materials: Either glucose (natural) or acetic acid (synthetic intermediate)
• Production methods: Chemical synthesis from acetic acid (dominant) or microbial fermentation of glucose (emerging “green” method)
• Natural occurrence: Found naturally in fruits, vegetables, wine
• Final product: Chemically identical regardless of production method

Perceived “naturalness”: E363 is unique: while it’s synthetically manufactured, it’s genuinely natural in that it occurs in nature and is produced by human metabolism. Regulatory classification is “food additive” but it has exceptional “natural origin” status compared to other synthetics.

Vegetarian/vegan/dietary status:

• Vegan: Yes—no animal products in synthesis
• Vegetarian: Yes
• Kosher: Yes (pareve)
• Halal: Yes (when glucose source is compliant)
• Gluten-free: Yes
• Dairy-free: Yes

Natural Alternatives

Want to avoid E363 or looking for alternative acidifiers?

Some alternatives include:

• E330 (Citric acid) – Most common acidifier; much more widely used than E363
• E297 (Fumaric acid) – Related dicarboxylic acid; similar metabolic role
• E296 (Malic acid) – Apple acid; naturally occurring in fruits
• E334 (Tartaric acid) – Naturally occurring in grapes; similar acidity function
• E260 (Acetic acid) – Vinegar; strong acidifier
• E270 (Lactic acid) – Occurs in fermented foods
• E331-E333 (Citrate salts) – Sodium, potassium, calcium salts of citric acid
• Natural fruit juices – Contain natural acids (citric, malic, etc.)
• Vinegar or lemon juice – For some applications
• Simply accept higher pH: Use fresher ingredients; shorter shelf life

Unique Properties of E363

Succinic acid (E363) has several unique properties:

• Dicarboxylic acid structure: Two acidic groups provide stronger buffering than monocarboxylic acids
• Metabolic role: Normal intermediate in citric acid cycle (unlike many food additives)
• Umami properties: Provides umami taste component in addition to sour taste
• Low absorption: Limited absorption from GI tract; largely passes through
• Energy provision: Can be metabolized for energy/ATP production
• Chelation capacity: Can bind metal ions effectively
• Antimicrobial strength: Strong antimicrobial action at low concentrations (0.1%)
• Mild taste: Less harsh/sour flavor than some alternative acidifiers

The Bottom Line

E363 (succinic acid) is a naturally occurring organic acid and normal metabolic intermediate used as an acidity regulator, flavor enhancer, and preservative.

It’s found in limited food applications including flavored fermented milk, soups, powdered beverages, desserts, and some dairy products—where it provides pH buffering, flavor enhancement, and preservation.

E363 is approved by the FDA, EFSA, JECFA, and virtually all regulatory bodies worldwide with ADI “not specified,” indicating exceptional safety confidence.

Unique safety advantage: E363 is one of the safest food additives because it’s literally what your body produces continuously as part of normal energy metabolism in the citric acid cycle. This makes it fundamentally different from synthetic additives—your body already recognizes it as a normal biochemical compound.

For consumers: E363 is an excellent choice when encountered. It provides genuine “natural origin” status (occurring in fruits and metabolized naturally) combined with FDA/EFSA approval. However, it’s rarely encountered because its use is limited to specific applications where its particular properties are advantageous.

Industrial dominance: Most succinic acid production is used in chemical manufacturing (biodegradable polymers, resins, solvents) rather than in food—reflecting that it has greater value for industrial applications than as a food additive.

Emerging green chemistry role: Succinic acid is increasingly important in sustainable/bio-based manufacturing as a platform chemical produced from renewable resources (glucose fermentation), representing a shift away from petroleum-based chemicals.