Flavor ingredient regulatory record
beta-Isomethylionone
beta-Isomethylionone is a ketone in the floral family, FEMA GRAS under FEMA number 4151 (CAS 79-89-0). Its odor is sweet, floral, violet, powdery, fruity.
- FEMA
- 4151
- CAS
- 79-89-0
- JECFA
- 2186
- EU FL
- 07.041
- Formula
- C14H22O
- EC
- 201-231-1
GRAS status: FEMA GRAS, publication 22. Recorded by FDA in the Substances Added to Food inventory under CAS 79-89-0.
Structure
Identity
Also known as: 3-Buten-2-one, 3-methyl-4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-, 3-Methyl-4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-3-buten-2-one, δ-Iraldeine, Isomethyl-β-ionone, NSC 66433, β-Isomethylionone, 3-methyl-4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-3-buten-2-one, isomethyl-?-ionone, 3-methyl-4-(2,6,6-trimethylcyclohexen-1-yl)but-3-en-2-one, 3-buten-2-one, 3-methyl-4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-, 4-(2,6,6-trimethylcyclohex-1-en-1-yl)-3-methylbut-3-en-2-one.
Can beta-Isomethylionone be labeled natural?
The process decides for beta-Isomethylionone. It occurs in nature, so a natural-source, natural-process material is natural flavor in the US and synthetic beta-Isomethylionone is artificial. The EU and UK follow the same logic without a middle class; Mercosur and Mexico label synthetic beta-Isomethylionone 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
beta-Isomethylionone is FEMA GRAS under FEMA number 4151. 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 07.041, Annex I Part A under Regulation (EC) 1334/2008, evaluation status approved (EFSA). The UK retains the same list.
Purity. Mixture of E/Z isomers (50-70 % (E) and 30-50 % (Z))
JECFA (WHO / FAO)
JECFA number 2186, evaluated at the 79th meeting in 2014. No safety concern at current estimated dietary exposure 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. beta-Isomethylionone appears on the EPA Toxic Substances Control Act Chemical Substance Inventory under CAS 79-89-0, where EPA names it 3-Buten-2-one, 3-methyl-4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-.
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, floral, violet, powdery, fruity.
Where it is used
beta-Isomethylionone is used in fragrance, beverage, confection, personal care and flavoring, typically as a floral note.
Structurally similar flavor ingredients
Flavor ingredients with a GRAS determination closest to beta-Isomethylionone by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.
| Material | FEMA | Similarity | Occurrence |
|---|---|---|---|
| alpha-iso-Methylionone | 2714 | 98% | In nature |
| alpha-Irone | 2597 | 84% | In nature |
| beta-Ionol | 3625 | 82% | In nature |
| beta-Ionone | 2595 | 82% | In nature |
| Dihydro-alpha-ionone | 3628 | 82% | In nature |
More ketones in this index
Methyl-beta- ionone · 2-Aminoacetophenone · Methyl-delta-ionone · Ionone · alpha-Ionone · delta-Damascone
beta-Isomethylionone FAQ
Is beta-Isomethylionone on the FEMA GRAS list?
It is. FEMA number 4151 covers beta-Isomethylionone. The Code of Federal Regulations lists it at 21 CFR 172.515.
What is the FEMA number for beta-Isomethylionone?
The FEMA number for beta-Isomethylionone is 4151 and its CAS registry number is 79-89-0. Its flavor category is floral.
What is beta-Isomethylionone used for?
beta-Isomethylionone is described as sweet, floral, violet, powdery, fruity. It shows up in fragrance, beverage, confection, personal care and flavoring.
What did JECFA conclude about beta-Isomethylionone?
JECFA evaluated beta-Isomethylionone at the 79th meeting in 2014 under JECFA number 2186. The panel concluded: No safety concern at current estimated dietary exposure when used as a flavouring agent.
Is beta-Isomethylionone approved in the EU?
Yes. FL 07.041 is the Union List entry for beta-Isomethylionone, annex I Part A, under Regulation 1334/2008, and the UK keeps the same list.
Is beta-Isomethylionone natural or artificial?
Nature makes beta-Isomethylionone, which is why the US label turns on process. A natural route gives natural flavor; synthesis gives artificial beta-Isomethylionone, same molecule. The EU and UK grant the natural claim only to that natural route; Mercosur and Mexico call synthetic material identical-to-natural.
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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 BETA-ISOMETHYLIONONE under CAS 79-89-0 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.