Flavor ingredient regulatory record
(E,Z)-4-Methylpent-2-enoic acid
(E,Z)-4-Methylpent-2-enoic acid is an acid in the fruity family, FEMA GRAS under FEMA number 4180 (CAS 10321-71-8). Its odor is fruity, tart, green, berry.
- FEMA
- 4180
- CAS
- 10321-71-8
- JECFA
- 1818
- EU FL
- 08.099
- Formula
- C6H10O2
- EC
- 233-706-4
GRAS status: FEMA GRAS, publication 22. Recorded by FDA in the Substances Added to Food inventory under CAS 10321-71-8.
Structure
Identity
Also known as: 2-Pentenoic acid, 4-methyl-, 4-Methyl-2-pentenoic acid, 4,4-Dimethyl-2-butenoic acid, 4-Methylpent-2-en-1-oic acid, 4-methylpent-2-enoic acid, (2z)-4-methylpent-2-enoic acid, 4-methylpent-2-en-1-oic acid, 2-pentenoic acid, 4-methyl-, 4-methyl-2-pentenoic acid, (z)-4-methylpent-2-enoic acid, (z)-4-methyl-2-pentenoic acid, 4-methyl-2-pentenoic acid, (2z)-.
Can (E,Z)-4-Methylpent-2-enoic acid be labeled natural?
(E,Z)-4-Methylpent-2-enoic acid occurs in nature, so the label depends on the route: (E,Z)-4-Methylpent-2-enoic acid won from a natural source by a physical, enzymatic or microbiological process is natural flavor in the United States, and synthesized (E,Z)-4-Methylpent-2-enoic 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.
- 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
(E,Z)-4-Methylpent-2-enoic acid is FEMA GRAS under FEMA number 4180. 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 08.099, Annex I Part A under Regulation (EC) 1334/2008, evaluation status approved (EFSA). The UK retains the same list.
JECFA (WHO / FAO)
JECFA number 1818, evaluated at the 69th meeting in 2008. 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. (E,Z)-4-Methylpent-2-enoic acid appears on the EPA Toxic Substances Control Act Chemical Substance Inventory under CAS 10321-71-8, where EPA names it 2-Pentenoic acid, 4-methyl-.
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, tart, green, berry.
Where it is used
(E,Z)-4-Methylpent-2-enoic acid is used in beverage, confection, sauces and dressings, typically as a fruity note.
Structurally similar flavor ingredients
Flavor ingredients with a GRAS determination closest to (E,Z)-4-Methylpent-2-enoic acid by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.
| Material | FEMA | Similarity | Occurrence |
|---|---|---|---|
| 4-Methylpentanoic acid | 3463 | 96% | In nature |
| (E)-2-Pentenoic acid | 4193 | 92% | In nature |
| Valeric acid | 3101 | 91% | In nature |
| 3-Methylpentanoic acid | 3437 | 88% | In nature |
| 2,4-Dimethyl-2-pentenoic acid | 3143 | 85% | In nature |
More acids in this index
Undecanoic acid · Levulinic acid · o-trans-Coumaric acid · Cyclohexanecarboxylic acid · 4-Methyl-2-oxopentanoic acid · 2-Methyl-4-pentenoic acid
(E,Z)-4-Methylpent-2-enoic acid FAQ
Does (E,Z)-4-Methylpent-2-enoic acid have FEMA GRAS status?
(E,Z)-4-Methylpent-2-enoic acid holds FEMA GRAS status under FEMA number 4180. It is also codified at 21 CFR 172.515.
How do I cite (E,Z)-4-Methylpent-2-enoic acid by FEMA or CAS number?
Cite (E,Z)-4-Methylpent-2-enoic acid as FEMA 4180 or CAS 10321-71-8; both point to the same entry. FEMA files it in the fruity flavor category.
Can (E,Z)-4-Methylpent-2-enoic acid be labeled a natural flavor?
Since (E,Z)-4-Methylpent-2-enoic acid is found in nature, US labeling follows how it was obtained: natural flavor from a natural source and a natural process, artificial when (E,Z)-4-Methylpent-2-enoic acid is synthesized. 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.
Can (E,Z)-4-Methylpent-2-enoic acid be used in the EU and UK?
(E,Z)-4-Methylpent-2-enoic acid is on the EU Union List of flavouring substances as FL 08.099 (Annex I Part A) under Regulation 1334/2008.
Has JECFA evaluated (E,Z)-4-Methylpent-2-enoic acid?
Yes. JECFA number 1818, evaluated at the 69th meeting in 2008. Conclusion: No safety concern at current levels of intake when used as a flavouring agent.
What does (E,Z)-4-Methylpent-2-enoic acid smell and taste like, and where is it used?
The odor of (E,Z)-4-Methylpent-2-enoic acid is fruity, tart, green, berry. Typical uses are beverage, confection, sauces and dressings.
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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-METHYLPENT-2-ENOIC ACID under CAS 10321-71-8 and carries its FEMA number, its JECFA flavor number. 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.