Flavor ingredient regulatory record
5-Hydroxyundecanoic acid lactone
5-Hydroxyundecanoic acid lactone is a lactone in the fruity family, FEMA GRAS under FEMA number 3294 (CAS 710-04-3). Its odor is sweet, creamy, coconut, fruity, floral.
- FEMA
- 3294
- CAS
- 710-04-3
- JECFA
- 234
- EU FL
- 10.011
- Formula
- C11H20O2
- EC
- 211-915-1
GRAS status: FEMA GRAS, publication 5. Recorded by FDA in the Substances Added to Food inventory under CAS 710-04-3.
Structure
Identity
Also known as: 2H-Pyran-2-one, 6-hexyltetrahydro-, Undecanoic acid, 5-hydroxy-, δ-lactone, Hendecanoic acid, 5-hydroxy-, lactone, 6-Hexyltetrahydro-2H-pyran-2-one, δ-Hexylvalerolactone, Δ-Hexyl-Δ-valerolactone, δ-Undecalactone, 5-Undecanolide, (±)-δ-Undecalactone, (RS)-δ-Undecalactone, δ-Undecanolactone, 6-Hexyl-2H-tetrahydropyran-2-one.
Can 5-Hydroxyundecanoic acid lactone be labeled natural?
Since 5-Hydroxyundecanoic acid lactone is found in nature, US labeling follows how it was obtained: natural flavor from a natural source and a natural process, artificial when 5-Hydroxyundecanoic acid lactone 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.
- 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
5-Hydroxyundecanoic acid lactone is FEMA GRAS under FEMA number 3294. 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 10.011, Annex I Part A under Regulation (EC) 1334/2008, evaluation status approved (JECFA). The UK retains the same list.
JECFA (WHO / FAO)
JECFA number 234, 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. 5-Hydroxyundecanoic acid lactone appears on the EPA Toxic Substances Control Act Chemical Substance Inventory under CAS 710-04-3, where EPA names it 2H-Pyran-2-one, 6-hexyltetrahydro-.
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, creamy, coconut, fruity, floral.
Where it is used
5-Hydroxyundecanoic acid lactone is used in beverage, confection, dairy and fruit flavors, typically as a fruity note.
Structurally similar flavor ingredients
Flavor ingredients with a GRAS determination closest to 5-Hydroxyundecanoic acid lactone by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.
| Material | FEMA | Similarity | Occurrence |
|---|---|---|---|
| delta-Dodecalactone | 2401 | 97% | In nature |
| delta-Decalactone | 2361 | 97% | In nature |
| Hydroxynonanoic acid delta-lactone | 3356 | 92% | In nature |
| gamma-Decalactone | 2360 | 91% | In nature |
| (+/-) 3-Methyl-gamma-decalactone | 3999 | 89% | In nature |
More lactones in this index
Dehydromenthofurolactone · gamma-Decalactone · epsilon-Decalactone · 4-Hydroxy-3-methyloctanoic acid gamma-lactone · 2-(2-Hydroxyphenyl)-cyclopropanecarbocyclic acid delta-lactone · Hydroxynonanoic acid delta-lactone
5-Hydroxyundecanoic acid lactone FAQ
Is 5-Hydroxyundecanoic acid lactone FEMA GRAS?
Yes. The FEMA Expert Panel lists 5-Hydroxyundecanoic acid lactone as GRAS under FEMA number 3294. It is also codified at 21 CFR 172.515.
What are the FEMA and CAS numbers for 5-Hydroxyundecanoic acid lactone?
5-Hydroxyundecanoic acid lactone is FEMA 3294, CAS 710-04-3. FEMA files it in the fruity flavor category.
Does 5-Hydroxyundecanoic acid lactone count as natural in the US and the EU?
5-Hydroxyundecanoic acid lactone occurs in nature, so the label depends on the route: 5-Hydroxyundecanoic acid lactone won from a natural source by a physical, enzymatic or microbiological process is natural flavor in the United States, and synthesized 5-Hydroxyundecanoic acid lactone is artificial. The EU and UK follow the same logic without a middle class; Mercosur and Mexico label synthetic 5-Hydroxyundecanoic acid lactone identical-to-natural.
Is 5-Hydroxyundecanoic acid lactone on the EU Union List?
5-Hydroxyundecanoic acid lactone is on the EU Union List of flavouring substances as FL 10.011 (Annex I Part A) under Regulation 1334/2008.
Has JECFA evaluated 5-Hydroxyundecanoic acid lactone?
Yes. JECFA number 234, evaluated at the 49th meeting in 1997. Conclusion: No safety concern at current levels of intake when used as a flavouring agent.
How is 5-Hydroxyundecanoic acid lactone described, and where does it show up?
Flavorists describe 5-Hydroxyundecanoic acid lactone as sweet, creamy, coconut, fruity, floral. It is used in beverage, confection, dairy and fruit flavors.
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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 5-HYDROXYUNDECANOIC ACID LACTONE under CAS 710-04-3 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.