Flavor ingredient regulatory record
2-Butyl isothiocyanate
2-Butyl isothiocyanate is an isothiocyanate in the sulfur family, FEMA GRAS under FEMA number 4419 (CAS 4426-79-3). Its odor is pungent, mustard-like, sharp, sulfurous.
- FEMA
- 4419
- CAS
- 4426-79-3
- JECFA
- 1890
- Formula
- C5H9NS
GRAS status: FEMA GRAS, publication 23. Recorded by FDA in the Substances Added to Food inventory under CAS 4426-79-3.
Structure
Identity
Also known as: Butane, 2-isothiocyanato-, Isothiocyanic acid, sec-butyl ester, 2-Isothiocyanatobutane, sec-Butyl isothiocyanate, 1-Methylpropyl isothiocyanate, sec-butyl isothiocyanate, 2-isothiocyanatobutane, butane, 2-isothiocyanato-, 2-butylisothiocyanate, isothiocyanic acid, sec-butyl ester, 1-methylpropyl isothiocyanate, 2-butylisothiocyanate [fhfi].
Can 2-Butyl isothiocyanate be labeled natural?
The process decides for 2-Butyl isothiocyanate. It occurs in nature, so a natural-source, natural-process material is natural flavor in the US and synthetic 2-Butyl isothiocyanate is artificial. The EU and UK grant the natural claim only to that natural route; Mercosur and Mexico call synthetic material 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
2-Butyl isothiocyanate is FEMA GRAS under FEMA number 4419. 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-Butyl isothiocyanate. 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 1890, evaluated at the 69th meeting in 2008. No safety concern at current levels of intake when used as a flavouring agent.
Other US flags
Not on the California Proposition 65 list.
Odor and taste
Odor: Pungent, mustard-like, sharp, sulfurous.
Where it is used
2-Butyl isothiocyanate is used in seasoning, condiment, food preservation and flavoring, typically as a sulfur note.
Structurally similar flavor ingredients
Flavor ingredients with a GRAS determination closest to 2-Butyl isothiocyanate by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.
| Material | FEMA | Similarity | Occurrence |
|---|---|---|---|
| Butyl isothiocyanate | 4082 | 77% | In nature |
| Hexyl isothiocyanate | 4422 | 76% | In nature |
| 5-(Methylthio)pentyl isothiocyanate | 4416 | 76% | In nature |
| 5-Hexenyl isothiocyanate | 4421 | 75% | In nature |
| Isoamyl isothiocyanate | 4423 | 72% | In nature |
More isothiocyanates in this index
Isopropyl isothiocyanate · Hexyl isothiocyanate · 3-(Methylthio)propyl isothiocyanate · Methyl isothiocyanate · Isoamyl isothiocyanate · 5-(Methylthio)pentyl isothiocyanate
2-Butyl isothiocyanate FAQ
Is 2-Butyl isothiocyanate FEMA GRAS?
Yes. The FEMA Expert Panel lists 2-Butyl isothiocyanate as GRAS under FEMA number 4419. The Code of Federal Regulations lists it at 21 CFR 172.515.
What are the FEMA and CAS numbers for 2-Butyl isothiocyanate?
2-Butyl isothiocyanate is FEMA 4419, CAS 4426-79-3. Its flavor category is sulfur.
How is 2-Butyl isothiocyanate described, and where does it show up?
Flavorists describe 2-Butyl isothiocyanate as pungent, mustard-like, sharp, sulfurous. It is used in seasoning, condiment, food preservation and flavoring.
What did JECFA conclude about 2-Butyl isothiocyanate?
JECFA evaluated 2-Butyl isothiocyanate at the 69th meeting in 2008 under JECFA number 1890. The panel concluded: No safety concern at current levels of intake when used as a flavouring agent.
Is 2-Butyl isothiocyanate approved in the EU?
No EU FL number is on file for 2-Butyl isothiocyanate. It has a JECFA evaluation (JECFA 1890), which the EU list draws on, but the Union List entry itself should be confirmed before EU use.
Does 2-Butyl isothiocyanate count as natural in the US and the EU?
Nature makes 2-Butyl isothiocyanate, which is why the US label turns on process. A natural route gives natural flavor; synthesis gives artificial 2-Butyl isothiocyanate, same molecule. 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.
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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-BUTYLISOTHIOCYANATE under CAS 4426-79-3 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.