FlavScents AInsights Entry for cis-Oak Lactone (CAS: 55013-32-6)

1. Identity & Chemical Information

• Common Name(s): cis-Oak Lactone, Whisky Lactone
• IUPAC Name: (4R,4aR,6R,8aR)-4,6-dimethyl-3,4,4a,5,6,7,8,8a-octahydro-2H-chromen-2-one
• CAS Number: 55013-32-6
• FEMA Number: 3653
• Other Identifiers: FL No. 05.061
• Molecular Formula: C10H16O2
• Molecular Weight: 168.23 g/mol
• Functional Groups and Structure-Odor Relevance: cis-Oak lactone is a bicyclic lactone with a methyl group that contributes to its characteristic woody and coconut-like aroma. The stereochemistry of the molecule is crucial for its sensory properties, with the cis configuration being more potent than its trans counterpart.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

cis-Oak lactone is renowned for its distinctive woody, coconut, and creamy aroma, often described as reminiscent of freshly cut oak wood. It exhibits moderate to high intensity and is primarily used as an impact note in both flavors and fragrances. The odor threshold is relatively low, making it effective even at minimal concentrations. Its sensory role is often as a character-defining note, providing depth and complexity to formulations.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

cis-Oak lactone naturally occurs in oak wood, particularly in the heartwood of Quercus species. It is formed during the aging of alcoholic beverages in oak barrels, contributing to the flavor profile of whisky and other spirits. The compound is also produced through the thermal degradation of lignin during the toasting of oak barrels, a process that enhances its concentration and sensory impact.

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

4. Use in Flavors

cis-Oak lactone is widely used in flavor formulations, particularly in alcoholic beverages, baked goods, and confectionery. It serves as a key component in creating oak-aged profiles and enhancing the complexity of flavors. Typical use levels in finished products range from 0.1 to 5 ppm, with higher concentrations used in applications requiring a pronounced oak character. The compound is stable under typical processing conditions but may degrade under extreme heat or acidic conditions.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

In perfumery, cis-Oak lactone is utilized across various fragrance families, including woody, oriental, and gourmand. It acts as a modifier and impact note, providing a creamy, woody base that enhances the richness of compositions. Typical concentrations range from trace amounts to 0.5% in the final product, depending on the desired intensity. Its volatility places it in the middle to base note category, contributing to the fragrance's longevity.

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. 05.061.
• 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.

Explicit approvals exist for flavor use, while fragrance applications are subject to IFRA guidelines. Variability in regulatory acceptance may occur based on regional interpretations of safety data.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

For oral exposure, cis-Oak lactone is considered safe within the established GRAS limits, with an acceptable daily intake (ADI) not specifically defined but implied through usage levels. Dermal exposure in fragrances is generally safe, with low potential for irritation or sensitization, as per IFRA standards. Inhalation exposure is minimal due to its low volatility, but occupational safety measures should be observed during handling to prevent respiratory irritation.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

cis-Oak lactone is valued for its ability to impart a natural oak character to both flavors and fragrances. It synergizes well with vanilla, caramel, and other woody notes, enhancing the overall complexity. Formulators should be cautious of its potency, as overuse can lead to an overpowering aroma. It is often underutilized in non-alcoholic applications, where it can provide unique depth.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on cis-Oak lactone is well-established, with comprehensive sensory and regulatory information available. Industry practices are well-documented, though specific regional regulatory nuances may require further verification. Known data gaps are minimal, primarily related to long-term exposure studies.

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 2026-03-30 13:31:27 GMT (p2)