FlavScents AInsights Entry for 2,4-Undecadienal (CAS: 13162-46-4)

1. Identity & Chemical Information

• Common Name(s): 2,4-Undecadienal
• IUPAC Name: Undeca-2,4-dienal
• CAS Number: 13162-46-4
• FEMA Number: 3422
• Other Identifiers: FL No. 02.084
• Molecular Formula: C11H18O
• Molecular Weight: 166.26 g/mol

2,4-Undecadienal is an unsaturated aldehyde characterized by its conjugated diene system, which contributes to its potent odor profile. The presence of the aldehyde group is crucial for its reactivity and sensory impact, often associated with fatty, citrus, and green notes.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

2,4-Undecadienal is renowned for its strong, fatty, citrus-like odor with nuances of green and aldehydic notes. It is often described as having a powerful, diffusive character that can dominate a fragrance or flavor composition. The odor threshold is relatively low, making it effective even at minimal concentrations. Its sensory role typically involves providing impact notes and enhancing the realism of citrus and fatty profiles.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

2,4-Undecadienal is naturally found in various citrus oils and is a product of lipid oxidation in certain foodstuffs. It can form through the degradation of linoleic acid, a common fatty acid, via enzymatic or oxidative pathways. This compound is often associated with natural flavor designations due to its occurrence in natural sources.

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

4. Use in Flavors

2,4-Undecadienal is utilized in flavor formulations to impart citrus, fatty, and green notes. It is commonly used in citrus-flavored beverages, dairy products, and savory applications. Typical use levels range from 0.1 to 5 ppm in finished products, with higher concentrations potentially leading to overpowering effects. It is relatively stable under acidic conditions but may degrade under high heat or oxidative environments.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

In perfumery, 2,4-undecadienal is valued for its ability to add freshness and complexity to citrus, green, and aldehydic fragrance families. It serves as a top note due to its volatility and is used in concentrations typically ranging from trace amounts to 0.5% in formulations. Its role often includes providing realism and enhancing the overall brightness of a fragrance.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

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

Explicit approvals and harmonized assumptions are prevalent, though some variability exists in specific country regulations.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

For oral exposure, 2,4-undecadienal is considered safe within established FEMA GRAS limits, with an acceptable daily intake (ADI) not clearly reported but generally recognized as safe at typical use levels. Dermal exposure in fragrances is subject to IFRA guidelines, with potential for irritation or sensitization at higher concentrations. Inhalation exposure is minimal due to its low volatility, but occupational safety measures should be observed.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

2,4-Undecadienal is prized for its ability to impart authentic citrus and fatty notes, making it a versatile component in both flavor and fragrance formulations. It synergizes well with other aldehydes and citrus oils. Formulators should be cautious of its potency to avoid overpowering effects and consider its stability under various conditions.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

Data on 2,4-undecadienal is well-established, with comprehensive sensory and regulatory information available. Industry practices are well-documented, though some regional regulatory nuances may require further verification.

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 2026-05-22 07:00:01 GMT (p2)