AInsights Entry for 3-mercapto-2-butanone (CAS: 40789-98-8)

1. Identity & Chemical Information

3-mercapto-2-butanone, also known as 3-sulfanylbutan-2-one, is a chemical compound with the CAS number 40789-98-8. It is identified by the molecular formula C4H8OS and has a molecular weight of 104.17 g/mol. This compound is characterized by the presence of a thiol group, which significantly influences its odor profile, contributing to its potent aroma. The functional groups present in 3-mercapto-2-butanone are crucial for its sensory characteristics, often described as sulfurous and reminiscent of cooked meat or savory notes.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

3-mercapto-2-butanone is known for its strong, sulfurous odor, often described as meaty, savory, or reminiscent of cooked onions. Its intensity is high, and it can be perceived at low concentrations, making it a powerful impact note in flavor formulations. The compound's odor threshold is notably low, although specific quantitative thresholds are not widely reported. It is typically used to impart a realistic background note in savory flavor applications, enhancing the umami character of food products.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

This compound is not commonly found in nature but can be formed through the Maillard reaction, a chemical reaction between amino acids and reducing sugars that occurs during the cooking of foods. It may also be produced during fermentation processes. Its formation in these contexts contributes to the complex flavor profiles of cooked and fermented foods, aligning with its use in "natural flavor" designations when derived from such processes.

Citation hooks: FlavScents; food chemistry literature; EFSA/JECFA monographs

4. Use in Flavors

3-mercapto-2-butanone is primarily used in savory flavor applications, such as meat, poultry, and vegetable flavors. It serves as an impact note, providing depth and authenticity to flavor profiles. Typical use levels in finished food products are low, often in the range of 0.1 to 5 ppm, depending on the desired intensity and the specific application. The compound is relatively stable under typical processing conditions but may degrade under extreme heat or oxidative environments.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

In fragrance applications, 3-mercapto-2-butanone is used sparingly due to its potent odor. It can be found in fragrance compositions that require a sulfurous or savory note, often as a trace component to add realism or complexity. Its volatility makes it more suitable for top or middle notes in fragrance formulations. Typical concentrations are very low, often below 0.1%, to prevent overpowering the fragrance blend.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

In the United States, 3-mercapto-2-butanone is recognized under FEMA GRAS status for flavor use. In the European Union, it is subject to the regulations outlined in Regulation (EC) No 1334/2008, although specific FL number status may not be clearly reported. Post-Brexit, the United Kingdom aligns closely with EU regulations. In Asia, regulatory acceptance varies, with Japan and China having specific guidelines for flavor compounds. In Latin America, countries like Brazil follow MERCOSUR regulations, which may include this compound under general flavoring guidelines.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

For oral exposure, 3-mercapto-2-butanone is considered safe at typical flavor use levels, with no specific ADI or MSDI reported. Dermal exposure in fragrance applications should be approached with caution due to potential irritation or sensitization, although it is not a common allergen. Inhalation exposure is generally low risk at typical use levels, but occupational exposure should be managed to avoid irritation. The risk profiles for food and fragrance applications are similar, with primary concerns related to concentration and exposure duration.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

3-mercapto-2-butanone is valued for its ability to impart a realistic savory note, enhancing umami and cooked meat flavors. It synergizes well with other sulfur-containing compounds and umami enhancers. Formulators should be cautious of its potency, as overuse can lead to an undesirable sulfurous character. It is often under-used in applications where a subtle savory note could enhance complexity.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on 3-mercapto-2-butanone is well-established in terms of its sensory profile and typical use levels. However, specific regulatory details and toxicological thresholds are less documented, requiring formulators to rely on industry-typical practices and expert judgment. Known data gaps include precise odor thresholds and comprehensive regulatory listings across all regions.

Citation hooks: FlavScents

QA Check

• All required sections 1–9 are present
• "Citation hooks:" line is present under each section
• Flavor section includes ppm ranges
• Toxicology section covers oral, dermal, inhalation
• Regulatory section mentions US, EU, UK, Asia, Latin America
• If complex natural material: includes section 5a (not applicable here)

About FlavScents AInsights (Disclosure)
FlavScents AInsights integrates information from authoritative government, scientific, academic, and industry sources to provide applied, exposure-aware insight into flavor and fragrance materials. Data are drawn from regulatory bodies, expert safety panels, peer-reviewed literature, public chemical databases, and long-standing professional practice within the flavor and fragrance community. Where explicit published values exist, they are reported directly; where gaps remain, AInsights reflects widely accepted industry-typical practice derived from convergent sensory behavior, historical commercial use, regulatory non-objection, and expert consensus. All such information is clearly labeled to distinguish documented data from professional guidance or informed estimation, with the goal of offering transparent, practical, and scientifically responsible context for researchers, formulators, and regulatory specialists. This section is generated using advanced computational language modeling to synthesize and structure information from established scientific and regulatory knowledge bases, with the intent of supporting—not replacing—expert review and judgment.

Generated 2026-03-12 11:10:43 GMT (p2)