Flavor ingredient regulatory record
4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one
4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one is a furanone in the sweet family, FEMA GRAS under FEMA number 3634 (CAS 28664-35-9). Its odor is caramel, sweet, brown sugar, maple.
- FEMA
- 3634
- CAS
- 28664-35-9
- JECFA
- 243
- EU FL
- 10.030
- Formula
- C6H8O3
- EC
- 249-136-4
GRAS status: FEMA GRAS, publication 12. Recorded by FDA in the Substances Added to Food inventory under CAS 28664-35-9.
Structure
Identity
Also known as: 2(5H)-Furanone, 3-hydroxy-4,5-dimethyl-, 3-Hydroxy-4,5-dimethyl-2(5H)-furanone, 3,4-Dimethyl-2-hydroxy-2-butan-1,4-olide, Sotolone, 4,5-Dimethyl-3-hydroxy-2(5H)-furanone, Sautalone, Sotolon, 3-hydroxy-4,5-dimethylfuran-2(5h)-one, sotolone, sotolon, 2(5h)-furanone, 3-hydroxy-4,5-dimethyl-, 2,3-dimethyl-4-hydroxy-2,5-dihydrofuran-5-one.
Can 4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one be labeled natural?
Since 4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one is found in nature, US labeling follows how it was obtained: natural flavor from a natural source and a natural process, artificial when 4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one is synthesized. The EU and UK follow the same logic without a middle class; Mercosur and Mexico label synthetic 4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one 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
4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one is FEMA GRAS under FEMA number 3634. 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 10.030, Annex I Part A under Regulation (EC) 1334/2008, evaluation status approved (JECFA/EFSA). The UK retains the same list.
JECFA (WHO / FAO)
JECFA number 243, 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. 4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one appears on the EPA Toxic Substances Control Act Chemical Substance Inventory under CAS 28664-35-9, where EPA names it 2(5H)-Furanone, 3-hydroxy-4,5-dimethyl-.
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 regulatory flags
| Flag | EPA definition | What it obliges |
|---|---|---|
| PMN | Indicates a commenced PMN substance. | Nothing new. The substance already went through premanufacture review and someone filed a notice of commencement, which is why it is on the Inventory. It is an existing chemical and needs no new premanufacture notice. Read more |
PMN does not establish: The flag records how the substance arrived, not what may be done with it. Check the flags beside it.
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: Caramel, sweet, brown sugar, maple. Detectable at about 0 ppm.
Taste: Sweet, caramel, roasted.
Where it is used
4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one is used in caramel, maple and brown sugar, typically as a sweet note.
Structurally similar flavor ingredients
Flavor ingredients with a GRAS determination closest to 4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.
| Material | FEMA | Similarity | Occurrence |
|---|---|---|---|
| 4-Hydroxy-2,5-dimethyl-3(2H)-furanone | 3174 | 94% | In nature |
| Maltol | 2656 | 88% | In nature |
| 4-Hydroxy-5-methyl-3(2H)-furanone | 3635 | 85% | In nature |
| Methylcyclopentenolone | 2700 | 80% | In nature |
| 2,5-Dimethylfuran-3(2H)-one | 4101 | 77% | Not determined |
More furanones in this index
4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one FAQ
Does 4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one have FEMA GRAS status?
4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one holds FEMA GRAS status under FEMA number 3634. It is also codified at 21 CFR 172.515.
How do I cite 4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one by FEMA or CAS number?
Cite 4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one as FEMA 3634 or CAS 28664-35-9; both point to the same entry. FEMA files it in the sweet flavor category.
Can 4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one be labeled a natural flavor?
4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one occurs in nature, so the label depends on the route: 4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one won from a natural source by a physical, enzymatic or microbiological process is natural flavor in the United States, and synthesized 4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one is artificial. The EU and UK grant the natural claim only to that natural route; Mercosur and Mexico call synthetic material identical-to-natural.
Can 4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one be used in the EU and UK?
4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one is on the EU Union List of flavouring substances as FL 10.030 (Annex I Part A) under Regulation 1334/2008.
Has JECFA evaluated 4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one?
Yes. JECFA number 243, evaluated at the 49th meeting in 1997. Conclusion: No safety concern at current levels of intake when used as a flavouring agent.
What does 4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one smell and taste like, and where is it used?
The odor of 4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one is caramel, sweet, brown sugar, maple. On the palate it is sweet, caramel, roasted. Its odor threshold is about 2.0E-5 ppm. Typical uses are caramel, maple and brown sugar.
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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 4,5-DIMETHYL-3-HYDROXY-2,5-DIHYDROFURAN-2-ONE under CAS 28664-35-9 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.