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

1. Identity & Chemical Information

Grapefruit mercaptan, also known as 4-mercapto-4-methylpentan-2-one, is a sulfur-containing compound with the CAS number 71159-90-5. It is recognized by its IUPAC name and is often referred to in the industry by its common name due to its distinctive grapefruit-like aroma. The molecular formula for grapefruit mercaptan is C6H12OS, and it has a molecular weight of 132.23 g/mol. This compound is characterized by the presence of a thiol group, which is crucial for its odor profile, contributing to its potent and characteristic grapefruit scent. The functional groups present in grapefruit mercaptan are responsible for its high volatility and strong odor impact, making it a valuable component in flavor and fragrance formulations.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

Grapefruit mercaptan is renowned for its intense and distinctive grapefruit aroma, which is both fresh and zesty. The odor is described as having a strong citrus character with sulfurous undertones, contributing to its high impact in formulations. The compound is used primarily as an impact note due to its potent scent, which can be perceived at very low concentrations. The odor threshold for grapefruit mercaptan is notably low, allowing it to impart a significant sensory effect even in trace amounts. Its role in formulations is often to provide a realistic grapefruit note, enhancing the overall freshness and authenticity of citrus profiles.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

Grapefruit mercaptan occurs naturally in grapefruit and is a key contributor to the fruit's characteristic aroma. It is formed through enzymatic processes within the fruit, particularly during ripening. The presence of this compound is crucial for the designation of "natural flavor" in products that aim to replicate the authentic taste and aroma of grapefruit. Its natural occurrence in grapefruit makes it a desirable component in flavor formulations seeking to achieve a natural label.

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

4. Use in Flavors

In flavor applications, grapefruit mercaptan is primarily used in citrus flavor formulations, particularly those aiming to replicate or enhance grapefruit profiles. It serves as an impact note, providing a burst of authentic grapefruit aroma. Typical use levels in finished food or beverage products range from 0.1 to 1 ppm, with variations depending on the desired intensity and product matrix. The compound is stable under typical processing conditions but may degrade under extreme heat or oxidative environments, which formulators should consider during product development.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

Grapefruit mercaptan is utilized in fragrance compositions to impart a fresh, citrusy top note. It is commonly found in fragrance families such as citrus, fruity, and fresh accords. Its role is often as a modifier or impact note, providing a realistic grapefruit scent that enhances the overall freshness of the fragrance. Typical concentration ranges in fragrance formulations are from trace amounts up to 0.5%, depending on the desired intensity and product type. Due to its high volatility, grapefruit mercaptan contributes primarily to the top notes of a fragrance composition.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

In the United States, grapefruit mercaptan is recognized as Generally Recognized As Safe (GRAS) for flavor use by FEMA. In the European Union, it is regulated under Regulation (EC) No 1334/2008, with specific use levels and conditions. The United Kingdom follows similar regulations post-Brexit, maintaining alignment with EU standards. In Asia, countries like Japan and China have their own regulatory frameworks, which generally align with international standards, though specific approvals may vary. In Latin America, countries such as Brazil and those in MERCOSUR have adopted regulations that are generally harmonized with international norms, though local variations may exist.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

Grapefruit mercaptan's safety profile is well-documented for its intended uses. For oral exposure in flavor applications, it is considered safe at typical use levels, with a wide margin of safety. Dermal exposure in fragrance applications is generally low risk, though formulators should consider potential sensitization in sensitive individuals. Inhalation exposure is minimal due to its low use levels and high volatility, but occupational exposure should be managed with appropriate ventilation and handling practices. The risk profiles for food and fragrance applications are similar, with no significant differences noted.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

Grapefruit mercaptan is valued for its ability to impart a realistic and intense grapefruit aroma, making it a critical component in citrus flavor and fragrance formulations. It synergizes well with other citrus and fruity notes, enhancing the overall freshness and authenticity of the product. Formulators should be cautious of its potent odor, as overuse can lead to an overpowering scent. It is often under-used in formulations seeking a subtle grapefruit note, where its impact can be finely tuned to achieve the desired effect.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on grapefruit mercaptan is well-established, with comprehensive sensory and safety profiles documented in authoritative sources. Industry practices are well-documented, though some undocumented practices may exist due to proprietary formulations. Known data gaps are minimal, with regulatory frameworks providing clear guidance on its use in both flavor and fragrance applications.

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 2026-05-03 00:57:39 GMT (p2)