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

1. Identity & Chemical Information

Grapefruit mercaptan, also known as 1-p-menthene-8-thiol, is a sulfur-containing compound with the CAS number 71159-90-5. It is recognized for its potent grapefruit-like aroma. The molecular formula is C10H18S, and it has a molecular weight of 170.32 g/mol. The compound features a thiol group, which is crucial for its characteristic odor. The presence of this functional group is responsible for the compound's high odor intensity and its role as a key impact odorant in grapefruit flavors.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

Grapefruit mercaptan is renowned for its strong, fresh, and zesty grapefruit aroma. It is often described as having a sulfurous, citrusy, and slightly sweet scent. The compound is highly diffusive and can be perceived at very low concentrations, making it an impactful note in flavor formulations. The odor threshold is extremely low, typically in the parts per billion (ppb) range, which underscores its potency as a flavor and fragrance component.

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 reactions during the ripening process of the fruit. This compound is significant for the "natural flavor" designation in citrus-based products, as it contributes to the authentic grapefruit aroma profile.

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

4. Use in Flavors

In flavor applications, grapefruit mercaptan is used primarily in citrus and tropical fruit flavors. It serves as an impact note, providing authenticity and enhancing the overall citrus character of the flavor profile. Typical use levels in finished food or beverage products range from 0.1 to 1 ppm, depending on the desired intensity and the complexity of the flavor system. The compound is relatively stable under normal conditions but can degrade under high heat or acidic conditions.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

Grapefruit mercaptan is utilized in fragrance formulations to impart a fresh, citrusy top note. It is commonly found in citrus, fruity, and fresh fragrance families. The compound acts as a modifier, enhancing the realism of grapefruit and other citrus scents. Typical concentration ranges in fragrance products are from trace amounts up to 0.5%, depending on the formulation. Its high volatility makes it a prominent top note in perfumery.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

In the United States, grapefruit mercaptan is recognized as GRAS (Generally Recognized As Safe) by FEMA for flavor use. In the European Union, it is regulated under the EC No 1334/2008 framework for flavorings. The compound is also approved for use in flavors in the United Kingdom, Japan, and other regions, although specific regulatory details may vary. In Latin America, it is generally accepted in flavor applications, but formulators should verify compliance with local regulations.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

For oral exposure, grapefruit mercaptan is considered safe at the low concentrations typically used in flavor applications, with a wide margin of safety. Dermal exposure in fragrance use is generally low risk, but formulators should consider potential sensitization in sensitive individuals. Inhalation exposure is minimal due to the low concentrations used in both flavors and fragrances. Overall, the risk profiles for food and fragrance applications are similar, with no significant safety concerns reported.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

Grapefruit mercaptan is valued for its ability to impart a true-to-life grapefruit aroma, making it indispensable in citrus flavor formulations. It synergizes well with other citrus and tropical fruit notes, enhancing the overall freshness and authenticity. Formulators should be cautious of its potency, as even small deviations in concentration can significantly alter the flavor profile. It is often under-used due to its strong odor, but when balanced correctly, it can elevate a formulation significantly.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on grapefruit mercaptan is well-established, with comprehensive sensory and regulatory information available. Industry practices are well-documented, although specific use levels may vary based on proprietary formulations. There are no significant data gaps or regulatory ambiguities identified for this compound.

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 2026-09-14 14:27:15 GMT (p2)