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. 02.062
• 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 properties, often imparting a fatty, citrus-like aroma that is highly valued in flavor and fragrance applications.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

2,4-Undecadienal is renowned for its strong, fatty, citrus-like odor with nuances of orange peel and grapefruit. It is often described as having a fresh, aldehydic character with a high intensity and good diffusion. The compound is typically used as an impact note in formulations, providing a vibrant, zesty top note that enhances the overall sensory experience. The odor threshold is relatively low, making it effective even at minimal concentrations.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

2,4-Undecadienal is naturally found in citrus oils, particularly in orange and grapefruit. It can also be formed through the oxidative degradation of unsaturated fatty acids, a process that can occur during the storage and processing of oils. This compound is often used to impart a "natural flavor" designation due to its presence in natural sources.

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

4. Use in Flavors

2,4-Undecadienal is widely used in citrus, fruity, and fatty flavor categories. It serves as a key impact note in flavor systems, providing a fresh, zesty character that enhances the authenticity of citrus profiles. Typical use levels in finished food or beverage products range from 0.1 to 1 ppm, with higher concentrations potentially leading to overpowering effects. The compound 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 the fragrance industry, 2,4-undecadienal is utilized in citrus, floral, and aldehydic fragrance families. It acts as a top note, providing a fresh, vibrant opening to compositions. Typical concentrations in fragrance formulations range from trace amounts to 0.5%, depending on the desired intensity and product type. Its volatility makes it suitable for top note applications, contributing to the initial impression 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: Approved under Regulation (EC) No 1334/2008 with FL No. 02.062.
• 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 and harmonized assumptions are common, though country-specific variability may exist, particularly in Asia and Latin America.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

For oral exposure, 2,4-undecadienal is considered safe within the 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 fragrance applications is subject to IFRA guidelines, which recommend concentration limits to prevent irritation and sensitization. Inhalation exposure is minimal due to its low volatility, but occupational safety measures should be observed during handling.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

2,4-Undecadienal is valued for its ability to impart a fresh, citrusy note that enhances the realism of flavor and fragrance compositions. It synergizes well with other citrus and aldehydic compounds, but formulators should be cautious of its potency to avoid overpowering effects. It is often under-used in complex formulations where its impact can be diluted.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on 2,4-undecadienal is well-established, with comprehensive sensory and regulatory information available. Industry practices are well-documented, though some variability in natural occurrence data may exist due to differences in source materials.

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 2026-08-25 11:48:47 GMT (p2)