FlavScents AInsights Entry: Prenyl Mercaptan (CAS: 5287-45-6)

1. Identity & Chemical Information

• Common Name(s): Prenyl Mercaptan
• IUPAC Name: 3-Methyl-2-buten-1-thiol
• CAS Number: 5287-45-6
• FEMA Number: 3477
• Other Identifiers: FL No. 12.165
• Molecular Formula: C5H10S
• Molecular Weight: 102.20 g/mol

Prenyl mercaptan is characterized by its thiol functional group, which is crucial for its distinctive sulfurous odor. The presence of the isoprenyl group contributes to its unique aroma profile, making it a valuable compound in flavor and fragrance formulations.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

Prenyl mercaptan is known for its potent, sulfurous odor reminiscent of cooked cabbage or onions, with a fruity undertone. It is often described as having a strong, diffusive character that can be impactful even at low concentrations. The compound serves as an impact note in flavor compositions, providing authenticity and depth to savory profiles.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

Prenyl mercaptan is naturally found in certain foods, such as cooked vegetables and some fermented products. It can form through the Maillard reaction during cooking processes, contributing to the complex aroma of cooked foods. Its presence in natural sources supports its use in "natural flavor" designations.

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

4. Use in Flavors

Prenyl mercaptan is primarily used in savory flavor applications, such as soups, sauces, and meat analogs, where it enhances the authenticity of cooked vegetable and meat notes. Typical use levels in finished food products range from 0.1 to 1 ppm, with higher concentrations potentially leading to overpowering sulfurous notes. It is relatively stable under typical cooking conditions but may degrade under prolonged heat exposure.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

In fragrance formulations, prenyl mercaptan is used sparingly due to its strong odor. It is typically employed in trace amounts to add realism and complexity to green and herbal fragrance families. Its volatility makes it a top note contributor, providing an initial burst of freshness that quickly dissipates.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

• United States: Recognized as GRAS by FEMA for flavor use.
• European Union: Approved under Regulation (EC) No 1334/2008 with FL No. 12.165.
• United Kingdom: Aligns with EU regulations post-Brexit.
• Asia: Approved for use in Japan and China, with specific concentration limits.
• Latin America: Generally accepted in Brazil and MERCOSUR countries, subject to local regulations.

Prenyl mercaptan's regulatory status is well-established in major markets, though formulators should verify specific regional requirements.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

Prenyl mercaptan's safety profile is primarily evaluated through its use in flavors. Oral exposure is considered safe within established GRAS limits, with an acceptable daily intake (ADI) not specifically defined but implied through typical use levels. Dermal exposure in fragrances is limited due to potential irritation, and IFRA guidelines should be consulted. Inhalation exposure is minimal due to its low volatility in typical use concentrations.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

Prenyl mercaptan is valued for its ability to impart authentic sulfurous notes, enhancing the realism of savory flavors. It synergizes well with other sulfur compounds and can be challenging to balance due to its potency. Formulators should be cautious of overuse, which can lead to undesirable off-notes.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on prenyl mercaptan is well-documented, with established sensory and regulatory profiles. Industry practices are generally consistent, though specific use levels may vary by application. Some data gaps exist in detailed toxicological studies, but current usage levels are considered safe.

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

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 2026-01-26 15:09:38 GMT (p2)