Flavor ingredient regulatory record
Methyl isobutanethioate
Methyl isobutanethioate is a thiol in the fruity family, FEMA GRAS under FEMA number 4586 (CAS 42075-42-3).
- FEMA
- 4586
- CAS
- 42075-42-3
- JECFA
- 1937
- Formula
- C5H10OS
GRAS status: FEMA GRAS, publication 24. Recorded by FDA in the Substances Added to Food inventory under CAS 42075-42-3.
Structure
Identity
Also known as: s-methyl 2-methylpropanethioate, propanethioic acid, 2-methyl-, s-methyl ester, methyl thioisobutyric acid, s-methyl thioisobutyrate.
Can Methyl isobutanethioate 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
Methyl isobutanethioate is FEMA GRAS under FEMA number 4586. 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 Methyl isobutanethioate. 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 1937, evaluated at the 73rd meeting in 2010. 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
Taste: Savory, slightly sweet, umami.
Where it is used
Methyl isobutanethioate is used in beverage, confection, fruit flavors, savory dishes and seasonings, typically as a fruity note.
Structurally similar flavor ingredients
Flavor ingredients with a GRAS determination closest to Methyl isobutanethioate by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.
| Material | FEMA | Similarity | Occurrence |
|---|---|---|---|
| 2,3-Pentadione | 2841 | 88% | In nature |
| 4-Methyl-2,3-pentanedione | 2730 | 88% | In nature |
| S-Methyl 2-methylbutanethioate | 3708 | 86% | Not determined |
| Methyl thiobutyrate | 3310 | 76% | In nature |
More thiols in this index
3-Mercaptohexanal · (S)-1-Methoxy-3-heptanthiol · (+/-) 3-(Ethylthio)butanol · 2,5-Dimethyl-3-furanthiol · 1-p-Menthene-8-thiol · 2-Pentenyl-4-propyl-1,3-oxathiane
Methyl isobutanethioate FAQ
Is methyl isobutanethioate on the FEMA GRAS list?
It is. FEMA number 4586 covers methyl isobutanethioate. It is also codified at 21 CFR 172.515.
What is the FEMA number for methyl isobutanethioate?
The FEMA number for methyl isobutanethioate is 4586 and its CAS registry number is 42075-42-3. FEMA files it in the fruity flavor category.
Is methyl isobutanethioate approved in the EU?
No EU FL number is on file for methyl isobutanethioate. It has a JECFA evaluation (JECFA 1937), which the EU list draws on, but the Union List entry itself should be confirmed before EU use.
Has JECFA evaluated methyl isobutanethioate?
Yes. JECFA number 1937, evaluated at the 73rd meeting in 2010. Conclusion: No safety concern at current levels of intake when used as a flavouring agent.
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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 METHYL ISOBUTANETHIOATE under CAS 42075-42-3 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.