Flavor ingredient regulatory record
5-Acetyl-2,3-dihydro-1,4-thiazine
5-Acetyl-2,3-dihydro-1,4-thiazine is a thiazine in the savory family, FEMA GRAS under FEMA number 4296 (CAS 164524-93-0). Its odor is savory, meaty, umami, roasted.
- FEMA
- 4296
- CAS
- 164524-93-0
- JECFA
- 1766
- Formula
- C6H9NOS
GRAS status: FEMA GRAS, publication 23. Recorded by FDA in the Substances Added to Food inventory under CAS 164524-93-0.
Structure
Identity
Also known as: Ethanone, 1-(3,4-dihydro-2H-1,4-thiazin-5-yl)-, 1-(3,4-Dihydro-2H-1,4-thiazin-5-yl)ethanone, 1-(3,4-dihydro-2h-1,4-thiazin-5-yl)ethanone, ethanone, 1-(3,4-dihydro-2h-1,4-thiazin-5-yl)-, 5-acetyl-2,3-dihydro-1,4-thiazine [fifh], 5-acetyl-2,3-dihydro-1,4-thiazine [fhfi], 5-acetyl-2,3-dihydro-1,4-thiazine (fifh), 1-(3,4-dihydro-2h-1,4-thiazin-5-yl)ethan-1-one, 5-acetyl-3,4-dihydro-2h-1,4-thiazine, ethanone, 1-(3,4-dihydro-2h-1,4-thiazin-5-yl)- (9ci), 5-acetyl-2,3-dihydro-1,4-thiazin, ts-01870.
Can 5-Acetyl-2,3-dihydro-1,4-thiazine be labeled natural?
5-Acetyl-2,3-dihydro-1,4-thiazine occurs in nature, so the label depends on the route: 5-Acetyl-2,3-dihydro-1,4-thiazine won from a natural source by a physical, enzymatic or microbiological process is natural flavor in the United States, and synthesized 5-Acetyl-2,3-dihydro-1,4-thiazine 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
5-Acetyl-2,3-dihydro-1,4-thiazine is FEMA GRAS under FEMA number 4296. 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 5-Acetyl-2,3-dihydro-1,4-thiazine. 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 1766, evaluated at the 68th meeting in 2008. no safety concern at current levels of intake.
Other US flags
Not on the California Proposition 65 list.
Odor and taste
Odor: Savory, meaty, umami, roasted.
Taste: Umami, savory, rich.
Where it is used
5-Acetyl-2,3-dihydro-1,4-thiazine is used in sauces, seasonings, snack foods and meat products, typically as a savory note.
Structurally similar flavor ingredients
Flavor ingredients with a GRAS determination closest to 5-Acetyl-2,3-dihydro-1,4-thiazine by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.
| Material | FEMA | Similarity | Occurrence |
|---|---|---|---|
| 2-(Methylthio)methyl-2-butenal | 3601 | 80% | In nature |
| 2-Acetylpyridine | 3251 | 79% | In nature |
| Methyl thiobutyrate | 3310 | 62% | In nature |
| 4-Hexen-3-one | 3352 | 62% | In nature |
| 2-Methylpiperidine | 4244 | 53% | In nature |
5-Acetyl-2,3-dihydro-1,4-thiazine FAQ
Is 5-Acetyl-2,3-dihydro-1,4-thiazine FEMA GRAS?
Yes. The FEMA Expert Panel lists 5-Acetyl-2,3-dihydro-1,4-thiazine as GRAS under FEMA number 4296. It is also codified at 21 CFR 172.515.
What are the FEMA and CAS numbers for 5-Acetyl-2,3-dihydro-1,4-thiazine?
5-Acetyl-2,3-dihydro-1,4-thiazine is FEMA 4296, CAS 164524-93-0. FEMA files it in the savory flavor category.
Does 5-Acetyl-2,3-dihydro-1,4-thiazine count as natural in the US and the EU?
Since 5-Acetyl-2,3-dihydro-1,4-thiazine is found in nature, US labeling follows how it was obtained: natural flavor from a natural source and a natural process, artificial when 5-Acetyl-2,3-dihydro-1,4-thiazine is synthesized. The EU and UK grant the natural claim only to that natural route; Mercosur and Mexico call synthetic material identical-to-natural.
Is 5-Acetyl-2,3-dihydro-1,4-thiazine approved in the EU?
No EU FL number is on file for 5-Acetyl-2,3-dihydro-1,4-thiazine. It has a JECFA evaluation (JECFA 1766), which the EU list draws on, but the Union List entry itself should be confirmed before EU use.
Has JECFA evaluated 5-Acetyl-2,3-dihydro-1,4-thiazine?
Yes. JECFA number 1766, evaluated at the 68th meeting in 2008. Conclusion: no safety concern at current levels of intake.
How is 5-Acetyl-2,3-dihydro-1,4-thiazine described, and where does it show up?
Flavorists describe 5-Acetyl-2,3-dihydro-1,4-thiazine as savory, meaty, umami, roasted. On the palate it is umami, savory, rich. It is used in sauces, seasonings, snack foods and meat products.
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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-ACETYL-2,3-DIHYDRO-1,4-THIAZINE under CAS 164524-93-0 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.