Flavor ingredient regulatory record
2,4-Hexadienyl isobutyrate
2,4-Hexadienyl isobutyrate is an ester in the fruity family, FEMA GRAS under FEMA number 4134 (CAS 16491-24-0). Its odor is sweet, fruity, berry, tropical, estery.
- FEMA
- 4134
- CAS
- 16491-24-0
- JECFA
- 1782
- Formula
- C10H16O2
- EC
- 240-551-6
GRAS status: FEMA GRAS, publication 22. Recorded by FDA in the Substances Added to Food inventory under CAS 16491-24-0.
Structure
Identity
Also known as: Propanoic acid, 2-methyl-, 2,4-hexadien-1-yl ester, Isobutyric acid, 2,4-hexadienyl ester, Propanoic acid, 2-methyl-, 2,4-hexadienyl ester, 2,4-Hexadien-1-ol, isobutyrate, NSC 195147, hexa-2,4-dienyl isobutyrate, sorbyl isobutyrate, 3,5-hexadienyl isobutyrate, 2,4-hexadienyl 2-methylpropanoate, 2-methylpropanoic acid 2,4-hexadienyl ester, isobutyric acid, 2,4-hexadienyl ester, ai3-32966.
Can 2,4-Hexadienyl isobutyrate be labeled natural?
Nature occurrence: Not yet found in nature (provisional).
Nature occurrence has not been settled for this substance, so the natural or artificial class is not stated here. The FEMA GRAS status does not depend on it.
Regulatory status, with citations
United States
2,4-Hexadienyl isobutyrate is FEMA GRAS under FEMA number 4134. It is cited in the Code of Federal Regulations at 21 CFR 172.515.
European Union and United Kingdom
No EU FL number is on file for 2,4-Hexadienyl isobutyrate. That is not a finding either way. The Union List covers defined flavouring substances, so natural complex materials are handled as flavouring preparations under Parts B to F and never receive a number, and substances used as additives sit under Regulation 1333/2008 instead. Confirm the position before EU or UK use.
JECFA (WHO / FAO)
JECFA number 1782, evaluated at the 68th meeting in 2007. 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. 2,4-Hexadienyl isobutyrate appears on the EPA Toxic Substances Control Act Chemical Substance Inventory under CAS 16491-24-0, where EPA names it Propanoic acid, 2-methyl-, 2,4-hexadien-1-yl ester.
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: Sweet, fruity, berry, tropical, estery.
Where it is used
2,4-Hexadienyl isobutyrate is used in beverage, confection, fruit flavors, bakery and ice cream, typically as a fruity note.
Structurally similar flavor ingredients
Flavor ingredients with a GRAS determination closest to 2,4-Hexadienyl isobutyrate by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.
| Material | FEMA | Similarity | Occurrence |
|---|---|---|---|
| 2,4-Hexadienyl propionate | 4131 | 92% | Not determined |
| cis-Hexenyl propionate | 3933 | 87% | Not determined |
| cis-Hexenyl tiglate | 3931 | 77% | In nature |
More esters in this index
Butan-3-one-2-yl butanoate · Octyl octanoate · alpha-Methylphenethyl butyrate · Tetrahydrofurfuryl cinnamate · Isoamyl benzoate · (Z)-3-Hexenyl 2-oxopropionate
2,4-Hexadienyl isobutyrate FAQ
Is 2,4-Hexadienyl isobutyrate FEMA GRAS?
Yes. The FEMA Expert Panel lists 2,4-Hexadienyl isobutyrate as GRAS under FEMA number 4134. It is also codified at 21 CFR 172.515.
What are the FEMA and CAS numbers for 2,4-Hexadienyl isobutyrate?
2,4-Hexadienyl isobutyrate is FEMA 4134, CAS 16491-24-0. FEMA files it in the fruity flavor category.
Is 2,4-Hexadienyl isobutyrate approved in the EU?
No EU FL number is on file for 2,4-Hexadienyl isobutyrate. It has a JECFA evaluation (JECFA 1782), which the EU list draws on, but the Union List entry itself should be confirmed before EU use.
Has JECFA evaluated 2,4-Hexadienyl isobutyrate?
Yes. JECFA number 1782, evaluated at the 68th meeting in 2007. Conclusion: No safety concern at current levels of intake when used as a flavouring agent.
How is 2,4-Hexadienyl isobutyrate described, and where does it show up?
Flavorists describe 2,4-Hexadienyl isobutyrate as sweet, fruity, berry, tropical, estery. It is used in beverage, confection, fruit flavors, bakery and ice cream.
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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 2,4-HEXADIENYL ISOBUTYRATE under CAS 16491-24-0 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.