E355 - Adipic acid

At a glance

• What it is: An organic acid also known as hexanedioic acid; it’s a white crystalline powder with a neutral aroma and a sour taste.¹
• What it does: Acts mainly as an acidity regulator and flavoring acid; helps set tartness and stabilize some gel textures.²
• Where it appears: Some powdered drink mixes, gelatin desserts, chewing gum, and other flavored dry mixes.
• On the label: “Adipic acid,” “E355,” or “hexanedioic acid.”
• Regulatory status: Authorised as E355 in the EU with defined purity criteria; permitted for use in the U.S. under FDA’s Food Additive Status List.²³⁴

Why is Adipic acid added to food?

Manufacturers use adipic acid to adjust pH and create a clean, lingering sour taste. It is valued in dry mixes because it dissolves when prepared and provides a steady acidity without sharp notes. In the EU, adipic acid is classified as an acidity regulator, meaning it is used to control the acidity or alkalinity of foods.²

What foods contain Adipic acid?

You’ll most often see adipic acid in:

• Flavored powdered drink mixes and ready-to-drink beverages that need a stable tart profile
• Gelatin desserts, where it supports tartness alongside the gel structure
• Chewing gum and candy, especially sour styles
• Dry mixes that are designed to rehydrate (desserts, beverages)

Look for “adipic acid” or “E355” in the ingredients list. It may appear together with other acids such as citric acid, malic acid, or fumaric acid.

What can replace Adipic acid?

Suitable substitutes depend on the food and the taste or performance you need:

• For a bright, quick tartness: citric acid
• For a smoother, apple-like sourness: malic acid
• For strong acidity in dry products: fumaric acid
• For wine/grape-like notes: L-tartaric acid
• In beverages where buffering is needed: sodium citrate or potassium citrate
• If you want to use a salt of adipic acid: sodium adipate or potassium adipate

How is Adipic acid made?

Most adipic acid is produced by oxidizing cyclohexanone and/or cyclohexanol (often called “KA oil”) with nitric acid. This well-established process also generates nitrous oxide (N2O) as a byproduct, which producers aim to control and abate.⁵ Food-grade adipic acid is then purified to meet specifications before use in foods.

Is Adipic acid safe to eat?

When used as intended in foods, adipic acid is considered safe by major regulators. In the EU, it is authorised as E355; in the United States, the Food and Drug Administration (FDA) includes adipic acid on its Food Additive Status List.²⁴ As with all additives, manufacturers must follow applicable rules on purity, permitted uses, and good manufacturing practice.

Does Adipic acid have any benefits?

Adipic acid does not add nutrients, but it does improve food quality:

• Taste: provides a clean, lasting tartness without overly sharp notes
• Stability: helps maintain a consistent pH in dry mixes and finished products
• Texture: can support gel structure in gelatin-based desserts, keeping the set firm and consistent

Who should avoid Adipic acid?

Most people can consume adipic acid in normal amounts found in foods. Those who are sensitive to acidic foods—such as some individuals with acid reflux—may prefer to limit strongly acidic products as advised by their healthcare professional.⁶ If you have a specific medical diet or allergy plan, follow your clinician’s guidance.

Myths & facts

• Myth: “Adipic acid is plastic.” Fact: Adipic acid is a chemical building block used to make nylon-6,6 in industry, but food-grade adipic acid is a purified ingredient made to strict specifications for use in foods.⁵³

• Myth: “All food acids are dangerous.” Fact: Many common acids—like citric acid from citrus fruits—are approved food additives and are used at levels set or overseen by regulators to make foods safe and palatable.⁴

Adipic acid in branded foods

• How it appears on labels: “Adipic acid,” “E355,” or “hexanedioic acid.”
• Where you might see it: powdered drink mixes, flavored gelatin desserts made with gelatine, sour candies or chewing gum, and other flavored dry mixes.
• Shopping tip: If you’re watching acidity, compare similar products—some use alternatives such as citric acid or malic acid.

References

Footnotes

1. Adipic acid (hexanedioic acid) — PubChem, National Institutes of Health (NIH). https://pubchem.ncbi.nlm.nih.gov/compound/Adipic-acid ↩

2. Regulation (EC) No 1333/2008 on food additives — European Union. https://eur-lex.europa.eu/eli/reg/2008/1333/oj ↩ ↩² ↩³ ↩⁴

3. Commission Regulation (EU) No 231/2012 laying down specifications for food additives — European Union. https://eur-lex.europa.eu/eli/reg/2012/231/oj ↩ ↩²

4. Food Additive Status List — U.S. Food and Drug Administration (FDA). https://www.fda.gov/food/food-additives-petitions/food-additive-status-list ↩ ↩² ↩³

5. AP-42, Section 6.9: Adipic Acid — U.S. Environmental Protection Agency (EPA). https://www3.epa.gov/ttn/chief/ap42/ch06/final/c06s09.pdf ↩ ↩²

6. Eating, Diet, & Nutrition for GER & GERD — National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), NIH. https://www.niddk.nih.gov/health-information/digestive-diseases/acid-reflux-ger-gerd-adults/eating-diet-nutrition ↩