Flavor ingredient regulatory record
2-Ethylbutyric acid
2-Ethylbutyric acid is an acid in the fruity family, FEMA GRAS under FEMA number 2429 (CAS 88-09-5). Its odor is fruity, sweet, apple, berry, estery.
- FEMA
- 2429
- CAS
- 88-09-5
- JECFA
- 257
- EU FL
- 08.045
- Formula
- C6H12O2
- EC
- 201-796-4
GRAS status: FEMA GRAS, publication 3. Recorded by FDA in the Substances Added to Food inventory under CAS 88-09-5.
Structure
Identity
Also known as: Butanoic acid, 2-ethyl-, Butyric acid, 2-ethyl-, Butyric acid, α-ethyl-, 2-Ethylbutanoic acid, Acetic acid, diethyl-, Diethylacetic acid, α-Ethylbutyric acid, 3-Pentanecarboxylic acid, 2-Ethyl-n-butyric acid, NSC 11765, NSC 8758, 2-ethylbutanoic acid.
Can 2-Ethylbutyric acid be labeled natural?
Nature makes 2-Ethylbutyric acid, which is why the US label turns on process. A natural route gives natural flavor; synthesis gives artificial 2-Ethylbutyric acid, same molecule. In the EU and UK the natural claim likewise needs the natural route, while Mercosur and Mexico keep a third class, identical-to-natural, for the synthetic material.
- United States
- Natural or artificial, by process
- European Union and UK
- Natural only from natural material
- Mercosur and Mexico
- Natural or identical-to-natural
How each market defines the classes: natural vs artificial flavor under 21 CFR 101.22.
Regulatory status, with citations
United States
2-Ethylbutyric acid is FEMA GRAS under FEMA number 2429. It is cited in the Code of Federal Regulations at 21 CFR 172.515.
European Union and United Kingdom
Listed on the Union List of flavouring substances as FL 08.045, Annex I Part A under Regulation (EC) 1334/2008, evaluation status approved (JECFA). The UK retains the same list.
JECFA (WHO / FAO)
JECFA number 257, evaluated at the 49th meeting in 1997. No safety concern at current levels of intake when used as a flavouring agent.
Other US flags
Not on the California Proposition 65 list.
TSCA Inventory status
A flavor ingredient is also an industrial chemical. 2-Ethylbutyric acid appears on the EPA Toxic Substances Control Act Chemical Substance Inventory under CAS 88-09-5, where EPA names it Butanoic acid, 2-ethyl-.
Active in US commerce
EPA designates this substance active, so no Notice of Activity Form B is required before manufacturing. What active and inactive mean.
EPA publishes no regulatory flags on this listing. What the flags mean.
From the EPA non-confidential TSCA Inventory, July 2026 release. EPA also maintains a confidential portion it does not publish. Search the Inventory by CAS number.
Odor and taste
Odor: Fruity, sweet, apple, berry, estery.
Where it is used
2-Ethylbutyric acid is used in beverage, confection, fruit flavors, dairy and savory dishes, typically as a fruity note.
Structurally similar flavor ingredients
Flavor ingredients with a GRAS determination closest to 2-Ethylbutyric acid by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.
| Material | FEMA | Similarity | Occurrence |
|---|---|---|---|
| 2-Methylbutyric acid | 2695 | 95% | In nature |
| Butyric acid | 2221 | 91% | In nature |
| Isovaleric acid | 3102 | 82% | In nature |
| 3-Hydroxy-2-pentanone | 3550 | 82% | In nature |
| 2-Pentanol | 3316 | 82% | In nature |
More acids in this index
3,7-Dimethyl-6-octenoic acid · trans-4-Octenoic acid · 4-Decenoic Acid · Cyclohexylacetic acid · 2,4-Dihydroxybenzoic acid · 4-Methyloctanoic acid
2-Ethylbutyric acid FAQ
Is 2-Ethylbutyric acid on the FEMA GRAS list?
It is. FEMA number 2429 covers 2-Ethylbutyric acid. The Code of Federal Regulations lists it at 21 CFR 172.515.
What is the FEMA number for 2-Ethylbutyric acid?
The FEMA number for 2-Ethylbutyric acid is 2429 and its CAS registry number is 88-09-5. Its flavor category is fruity.
What is 2-Ethylbutyric acid used for?
2-Ethylbutyric acid is described as fruity, sweet, apple, berry, estery. It shows up in beverage, confection, fruit flavors, dairy and savory dishes.
What did JECFA conclude about 2-Ethylbutyric acid?
JECFA evaluated 2-Ethylbutyric acid at the 49th meeting in 1997 under JECFA number 257. The panel concluded: No safety concern at current levels of intake when used as a flavouring agent.
Is 2-Ethylbutyric acid approved in the EU?
Yes. FL 08.045 is the Union List entry for 2-Ethylbutyric acid, annex I Part A, under Regulation 1334/2008, and the UK keeps the same list.
Is 2-Ethylbutyric acid natural or artificial?
The process decides for 2-Ethylbutyric acid. It occurs in nature, so a natural-source, natural-process material is natural flavor in the US and synthetic 2-Ethylbutyric acid is artificial. In the EU and UK the natural claim likewise needs the natural route, while Mercosur and Mexico keep a third class, identical-to-natural, for the synthetic material.
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Sources and attribution. The identity and regulatory facts on this page are taken from the FDA Substances Added to Food inventory, a US government record, which lists this substance as 2-ETHYLBUTYRIC ACID under CAS 88-09-5 and carries its FEMA number, its JECFA flavor number and its 21 CFR citations. The inventory is searchable at FDA. FDA records its technical effect as flavoring agent or adjuvant.
A FEMA GRAS conclusion is reached by the Expert Panel of the Flavor and Extract Manufacturers Association of the United States, and the FEMA number names that conclusion. FEMA publishes its own entry for this substance in the FEMA Flavor Library, which is the authoritative record of what the Panel decided and is worth reading alongside this page.
Ambrose Compliance is not affiliated with, endorsed by, or sponsored by FEMA. FEMA and FEMA GRAS are used here as identifiers for a published regulatory determination, not as marks of any relationship between FEMA and Ambrose.
About this page. Facts come from the FDA Substances Added to Food inventory, the Code of Federal Regulations, the EPA TSCA Inventory, the EU Union List, JECFA and the Ambrose database, with FEMA's published determination cited where it applies; parts of the text are written by Ambrose AI, which can make mistakes. Check the cited source before relying on anything here. This is not regulatory or legal advice.