Flavor ingredient regulatory record
4-Pentenoic acid
4-Pentenoic acid is an acid in the fruity family, FEMA GRAS under FEMA number 2843 (CAS 591-80-0). Its odor is fruity, green, slightly sour, fresh.
- FEMA
- 2843
- CAS
- 591-80-0
- JECFA
- 314
- EU FL
- 08.048
- Formula
- C5H8O2
GRAS status: FEMA GRAS, publication 3. Recorded by FDA in the Substances Added to Food inventory under CAS 591-80-0.
Structure
Identity
Also known as: Δ4-Pentenoic acid, Allylacetic acid, NSC 20944, NSC 9000, (3-Vinyl)propionic acid, MeSH ID: C009785, pent-4-enoic acid, allylacetic acid, allyl acetic acid, 3-vinylpropionic acid, 4 pa, .delta.4-pentenoic acid.
Can 4-Pentenoic acid be labeled natural?
The process decides for 4-Pentenoic acid. It occurs in nature, so a natural-source, natural-process material is natural flavor in the US and synthetic 4-Pentenoic acid is artificial. The EU and UK follow the same logic without a middle class; Mercosur and Mexico label synthetic 4-Pentenoic acid identical-to-natural.
- 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
4-Pentenoic acid is FEMA GRAS under FEMA number 2843. 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 08.048, Annex I Part A under Regulation (EC) 1334/2008, evaluation status approved (JECFA). The UK retains the same list.
JECFA (WHO / FAO)
JECFA number 314, evaluated at the 51st meeting in 1998. 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. 4-Pentenoic acid appears on the EPA Toxic Substances Control Act Chemical Substance Inventory under CAS 591-80-0, where EPA names it 4-Pentenoic acid.
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, green, slightly sour, fresh.
Where it is used
4-Pentenoic acid is used in beverage, sauces, condiments and fruit flavors, typically as a fruity note.
Structurally similar flavor ingredients
Flavor ingredients with a GRAS determination closest to 4-Pentenoic 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-Methyl-4-pentenoic acid | 3511 | 92% | In nature |
| (E)-2-Pentenoic acid | 4193 | 92% | In nature |
| Valeric acid | 3101 | 91% | In nature |
| (E,Z)-4-Methylpent-2-enoic acid | 4180 | 88% | In nature |
| 4-Pentenal | 4262 | 83% | In nature |
More acids in this index
Cyclohexylacetic acid · (E,Z)-4-Methylpent-2-enoic acid · 5-Oxododecanoic acid · 2,4-Dimethyl-2-pentenoic acid · Hydroxy(4-hydroxy-3-methoxyphenyl)acetic acid · cis-5-Octenoic acid
4-Pentenoic acid FAQ
Is 4-Pentenoic acid on the FEMA GRAS list?
It is. FEMA number 2843 covers 4-Pentenoic acid. The Code of Federal Regulations lists it at 21 CFR 172.515.
What is the FEMA number for 4-Pentenoic acid?
The FEMA number for 4-Pentenoic acid is 2843 and its CAS registry number is 591-80-0. Its flavor category is fruity.
What is 4-Pentenoic acid used for?
4-Pentenoic acid is described as fruity, green, slightly sour, fresh. It shows up in beverage, sauces, condiments and fruit flavors.
What did JECFA conclude about 4-Pentenoic acid?
JECFA evaluated 4-Pentenoic acid at the 51st meeting in 1998 under JECFA number 314. The panel concluded: No safety concern at current levels of intake when used as a flavouring agent.
Is 4-Pentenoic acid approved in the EU?
Yes. FL 08.048 is the Union List entry for 4-Pentenoic acid, annex I Part A, under Regulation 1334/2008, and the UK keeps the same list.
Is 4-Pentenoic acid natural or artificial?
Nature makes 4-Pentenoic acid, which is why the US label turns on process. A natural route gives natural flavor; synthesis gives artificial 4-Pentenoic acid, same molecule. The EU and UK grant the natural claim only to that natural route; Mercosur and Mexico call synthetic material identical-to-natural.
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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 4-PENTENOIC ACID under CAS 591-80-0 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 flavor enhancer, 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.