Flavor ingredient regulatory record
2-Hexenal
2-Hexenal is an aldehyde in the green family, FEMA GRAS under FEMA number 2560 (CAS 505-57-7). Its odor is grassy, green, fresh, cucumber, herbal.
- FEMA
- 2560
- CAS
- 505-57-7
- JECFA
- 1353
- EU FL
- 05.189
- Formula
- C6H10O
- EC
- 208-014-0
GRAS status: FEMA GRAS, publication 3. Recorded by FDA in the Substances Added to Food inventory under CAS 505-57-7.
Structure
Identity
Also known as: 2-Hexen-1-al, Hex-2-enal, trans-2-hexenal, (e)-2-hexenal, 2-trans-hexenal, 2-hexenal, (2e)-, hex-2-enal, (e)-hex-2-enal, leaf aldehyde, trans-2-hexen-1-al, trans-hex-2-enal, beta-propyl acrolein.
Can 2-Hexenal be labeled natural?
2-Hexenal occurs in nature, so the label depends on the route: 2-Hexenal won from a natural source by a physical, enzymatic or microbiological process is natural flavor in the United States, and synthesized 2-Hexenal 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
2-Hexenal is FEMA GRAS under FEMA number 2560. 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 05.189, Annex I Part A under Regulation (EC) 1334/2008, evaluation status approved (EFSA). The UK retains the same list.
Purity. At least 92%; secondary component 3-4% 2-hexenoic acid
JECFA (WHO / FAO)
JECFA number 1353, evaluated at the 63rd meeting in 2004. no safety concern at current levels of intake.
Other US flags
Not on the California Proposition 65 list.
TSCA Inventory status
A flavor ingredient is also an industrial chemical. 2-Hexenal appears on the EPA Toxic Substances Control Act Chemical Substance Inventory under CAS 505-57-7, where EPA names it 2-Hexenal.
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: Grassy, green, fresh, cucumber, herbal.
Where it is used
2-Hexenal is used in beverage, savory dishes and flavoring agents, typically as a green note.
Structurally similar flavor ingredients
Flavor ingredients with a GRAS determination closest to 2-Hexenal by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.
| Material | FEMA | Similarity | Occurrence |
|---|---|---|---|
| 3-Hexenal | 3923 | 98% | In nature |
| cis-3-Hexenal | 2561 | 98% | In nature |
| trans-4-Hexenal | 4046 | 97% | In nature |
| cis-4-Hexenal | 3496 | 97% | In nature |
| (E,E)-2,4-Hexadienal | 3429 | 96% | In nature |
More aldehydes in this index
3-Hexenal · Hexanal · 2-Hydroxy-4-methoxybenzaldehyde · (E,E)-2,4-Heptadienal · cis-3-Hexenal · Cuminaldehyde
2-Hexenal FAQ
Does 2-Hexenal have FEMA GRAS status?
2-Hexenal holds FEMA GRAS status under FEMA number 2560. It is also codified at 21 CFR 172.515.
How do I cite 2-Hexenal by FEMA or CAS number?
Cite 2-Hexenal as FEMA 2560 or CAS 505-57-7; both point to the same entry. FEMA files it in the green flavor category.
Can 2-Hexenal be labeled a natural flavor?
Since 2-Hexenal is found in nature, US labeling follows how it was obtained: natural flavor from a natural source and a natural process, artificial when 2-Hexenal 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 2-Hexenal be used in the EU and UK?
2-Hexenal is on the EU Union List of flavouring substances as FL 05.189 (Annex I Part A) under Regulation 1334/2008.
Has JECFA evaluated 2-Hexenal?
Yes. JECFA number 1353, evaluated at the 63rd meeting in 2004. Conclusion: no safety concern at current levels of intake.
What does 2-Hexenal smell and taste like, and where is it used?
The odor of 2-Hexenal is grassy, green, fresh, cucumber, herbal. Typical uses are beverage, savory dishes and flavoring agents.
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Guides: What Is FEMA GRAS? · Natural vs artificial · Filing a GRAS notification
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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-HEXENAL under CAS 505-57-7 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.