FlavScents AInsights Entry: Grapefruit Mercaptan (CAS: 71159-90-5)

1. Identity & Chemical Information

• Common Name(s): Grapefruit mercaptan
• IUPAC Name: 4-Methyl-4-sulfanylpentan-2-one
• CAS Number: 71159-90-5
• FEMA Number: Not available
• Other Identifiers: FL number not available; CoE number not available; IFRA reference not available
• Molecular Formula: C6H12OS
• Molecular Weight: 132.22 g/mol
• Functional Groups and Structure–Odor Relevance: Grapefruit mercaptan is characterized by a thiol group, which is crucial for its distinctive sulfurous, grapefruit-like aroma. The presence of the ketone group also contributes to its overall odor profile, enhancing its fruity and citrus notes.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

Grapefruit mercaptan is renowned for its potent and characteristic grapefruit aroma, which is both sulfurous and citrusy. It is often described as having a fresh, zesty, and slightly sweet scent with a strong impact. The intensity of its odor is high, making it a powerful impact note in both flavor and fragrance formulations. The odor threshold is notably low, allowing it to be perceived at very low concentrations, although specific threshold values are not clearly reported in the literature. Its typical sensory role is as an impact note, providing authenticity and realism to grapefruit and other citrus profiles.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

Grapefruit mercaptan is naturally found in grapefruit and other citrus fruits. It is formed through enzymatic processes that occur during the ripening of the fruit. This compound is significant in the designation of "natural flavor" due to its natural occurrence in citrus fruits, making it a valuable component in natural flavor formulations.

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

4. Use in Flavors

Grapefruit mercaptan is extensively used in flavor formulations, particularly in citrus and tropical fruit categories. It serves as a key impact note, enhancing the authenticity and freshness of grapefruit and other citrus flavors. Typical use levels in finished food or beverage products are not well-documented, but industry practices suggest usage in the range of 0.1 to 1 ppm, depending on the desired intensity and application. It is generally stable under typical flavor formulation conditions but may degrade under extreme heat or oxidative conditions.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

In fragrance applications, grapefruit mercaptan is used in citrus and fresh fragrance families. It acts as a modifier and impact note, providing a fresh, zesty top note that enhances the realism of citrus accords. Typical concentration ranges are qualitative, with trace amounts often sufficient to achieve the desired effect. Its volatility contributes to its role as a top note, providing an initial burst of freshness.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

• United States: Grapefruit mercaptan does not have a specific FEMA GRAS status but is used in accordance with general flavoring guidelines.
• European Union: Not explicitly listed under Reg. (EC) No 1334/2008; usage is based on general safety assessments.
• United Kingdom: Follows EU regulations post-Brexit with no significant divergence reported.
• Asia: Specific regulatory status in Japan, China, and ASEAN countries is not clearly documented; usage is typically aligned with international safety standards.
• Latin America: Regulatory information for Brazil and MERCOSUR is not explicitly available; general safety and usage guidelines apply.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

• Oral Exposure: Data on acceptable daily intake (ADI) or threshold of toxicological concern (TTC) is not clearly reported. Usage in flavors is generally considered safe at industry-typical levels.
• Dermal Exposure: No specific data on irritation or sensitization; however, its use in fragrances is typically at low concentrations, minimizing potential risks.
• Inhalation Exposure: Volatility suggests potential for inhalation exposure, but no specific occupational safety concerns are documented.

Overall, the risk profiles for food and fragrance applications are considered similar, with low exposure levels minimizing potential safety concerns.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

Grapefruit mercaptan is valued for its ability to impart a realistic grapefruit aroma, making it a crucial component in both flavor and fragrance formulations. It synergizes well with other citrus and tropical notes, enhancing overall freshness and authenticity. Common pitfalls include overuse, which can lead to an overpowering sulfurous note, and underuse, which may result in a lack of impact. Formulators should carefully balance its concentration to achieve the desired sensory effect.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on grapefruit mercaptan is well-established in terms of its sensory profile and natural occurrence. However, specific regulatory and toxicological data are less documented, relying on industry-typical practices and general safety assessments. Known data gaps include precise usage levels and regulatory specifics in certain 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 2026-02-24 18:15:04 GMT (p2)