FlavScents AInsights Entry for 2,4-Octadienal (CAS: 5577-44-6)

1. Identity & Chemical Information

• Common Name(s): 2,4-Octadienal
• IUPAC Name: (E,E)-2,4-Octadienal
• CAS Number: 5577-44-6
• FEMA Number: Data not found
• Other Identifiers: FL number not clearly reported; CoE number not found; IFRA reference not available
• Molecular Formula: C8H12O
• Molecular Weight: 124.18 g/mol
• Functional Groups and Structure–Odor Relevance: 2,4-Octadienal is an unsaturated aldehyde with conjugated double bonds, which are known to contribute to its potent odor profile. The aldehyde group is crucial for its reactivity and sensory characteristics, often imparting a green, fatty, and citrus-like aroma.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

2,4-Octadienal is characterized by a strong, penetrating odor with descriptors such as green, citrus, and fatty. It is known for its high intensity and diffusion, making it a powerful impact note in formulations. The compound's odor threshold is relatively low, although specific values are not clearly reported in the literature. It is typically used to impart freshness and complexity to both flavors and fragrances, often serving as a top note or an accentuating modifier.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

2,4-Octadienal occurs naturally in various plant sources, including citrus fruits and certain vegetables. It can form through the oxidative degradation of unsaturated fatty acids, a process that may occur during food processing or storage. This compound is relevant to the designation of "natural flavor" due to its presence in natural sources and its formation through natural biochemical pathways.

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

4. Use in Flavors

2,4-Octadienal is utilized in a variety of flavor categories, including citrus, green, and fatty profiles. It plays a functional role as an impact note, providing freshness and enhancing the authenticity of flavor systems. Typical use levels in finished food or beverage products range from 0.1 to 5 ppm, with higher concentrations potentially leading to overpowering effects. The compound is relatively stable under neutral pH conditions but may degrade under high heat or oxidative environments.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

In fragrance applications, 2,4-Octadienal is used across several fragrance families, including citrus, green, and herbal. It serves as a top note, contributing to the initial impression of freshness and vibrancy. Typical concentration ranges in fragrance formulations are from trace amounts up to 0.5%, depending on the desired intensity and product type. Its volatility makes it suitable for top and middle note contributions, enhancing the overall complexity of the fragrance.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

• United States: Not explicitly listed as FEMA GRAS; usage should comply with general safety standards.
• European Union: Not specifically listed under Reg. (EC) No 1334/2008; assumed to be used under general flavoring regulations.
• United Kingdom: Post-Brexit regulations align with EU standards; no specific divergence noted.
• Asia: Limited specific data; generally follows international safety guidelines.
• Latin America: Data not clearly reported; typically aligns with international norms.

Explicit approvals are not well-documented, and harmonized assumptions are generally applied. Known uncertainties exist due to the lack of specific listings in major regulatory frameworks.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

• Oral Exposure: Data on acceptable daily intake (ADI) or threshold of toxicological concern (TTC) is not clearly reported. Formulators should ensure usage levels are within industry-typical ranges to maintain safety.
• Dermal Exposure: Limited data on irritation or sensitization; formulators should consider IFRA guidelines for aldehydes.
• Inhalation Exposure: Volatility suggests potential for inhalation exposure; occupational safety measures should be considered in manufacturing settings.

Risk profiles may differ between food and fragrance applications, with fragrance use requiring careful consideration of dermal and inhalation exposure.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

2,4-Octadienal is valued for its ability to impart freshness and complexity to both flavors and fragrances. It synergizes well with other citrus and green notes, enhancing the overall profile. Common formulation pitfalls include overuse, leading to an overpowering effect, or underuse, resulting in a lack of desired impact. It is frequently used to add a natural touch to synthetic formulations.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on 2,4-Octadienal is well-established in terms of its sensory characteristics and general usage patterns. However, specific regulatory listings and toxicological data are less documented, leading to reliance on industry-typical practices and assumptions. Known data gaps include precise regulatory approvals and detailed toxicological thresholds.

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 2026-08-12 13:24:11 GMT (p2)