FlavScents AInsights Entry for (E)-2-hexenal (CAS: 85761-70-2)

1. Identity & Chemical Information

• Common Name(s): (E)-2-hexenal, Leaf Aldehyde
• IUPAC Name: (E)-hex-2-enal
• CAS Number: 85761-70-2
• FEMA Number: 3429
• Other Identifiers: FL No. 05.061
• Molecular Formula: C6H10O
• Molecular Weight: 98.15 g/mol
• Functional Groups and Structure–Odor Relevance: (E)-2-hexenal is an α,β-unsaturated aldehyde. The presence of the aldehyde group contributes to its characteristic green, leafy odor, which is often associated with freshly cut grass or unripe fruit. The double bond in the (E)-configuration enhances its reactivity and sensory impact.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

• Odor and Flavor Descriptors: (E)-2-hexenal is known for its strong, green, leafy odor reminiscent of freshly cut grass, green apple, and unripe fruit. It is often described as having a sharp, penetrating aroma with moderate to high intensity.
• Taste and/or Odor Thresholds: The odor threshold in water is reported to be around 0.1 ppm, indicating its potent sensory impact even at low concentrations.
• Typical Sensory Role: It serves as an impact note in flavor compositions, providing freshness and a green character. It can also act as a modifier to enhance the realism of fruit and vegetable flavors.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

• Known Natural Sources: (E)-2-hexenal is naturally found in a variety of fruits and vegetables, including apples, tomatoes, and green leafy vegetables. It is also present in essential oils such as peppermint and spearmint.
• Formation Pathways: It is typically formed through the enzymatic oxidation of linoleic acid, a common fatty acid in plant tissues, via the lipoxygenase pathway.
• Relevance to “Natural Flavor” or “Natural Fragrance” Designation: Due to its natural occurrence in many plants, (E)-2-hexenal is often used in formulations labeled as "natural."

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

4. Use in Flavors

• Flavor Categories and Applications: (E)-2-hexenal is widely used in fruit, vegetable, and herbal flavor formulations. It is particularly popular in apple, pear, and tomato flavors.
• Functional Role in Flavor Systems: It acts as an impact note and modifier, enhancing the freshness and authenticity of flavors.
• Typical Use Levels: Documented use levels in finished food products range from 0.1 to 5 ppm, with typical levels around 1 ppm. These values are industry-typical estimates.
• Stability Considerations: (E)-2-hexenal is relatively stable under acidic conditions but can undergo oxidation and polymerization under high heat and alkaline conditions, which may affect its sensory properties.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

• Fragrance Families and Product Types: It is used in green, herbal, and fruity fragrance compositions. Common applications include personal care products, household cleaners, and air fresheners.
• Functional Role: (E)-2-hexenal serves as a top note, providing freshness and a green character. It can also act as a modifier to enhance the naturalness of floral and fruity accords.
• Typical Concentration Ranges: It is typically used at concentrations of 0.01% to 0.1% in fragrance formulations.
• Volatility and Top/Middle/Base Contribution: As a highly volatile compound, (E)-2-hexenal contributes primarily to the top notes of a fragrance.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

• United States (FDA / FEMA GRAS): Recognized as GRAS (Generally Recognized As Safe) by FEMA for use in food flavors.
• European Union (Reg. (EC) No 1334/2008; FL Number Status): Approved for use as a flavoring substance under the EU flavoring regulation.
• United Kingdom (Post-Brexit Alignment or Divergence): Follows EU regulations; no significant divergence reported.
• Asia (Japan, China, ASEAN): Approved for use in food flavors, with specific regulations varying by country.
• Latin America (e.g., Brazil, MERCOSUR): Generally permitted in food flavors, subject to regional regulatory frameworks.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

• Oral Exposure: (E)-2-hexenal has a low acute oral toxicity. The estimated acceptable daily intake (ADI) is not clearly reported, but it is considered safe at typical use levels in food.
• Dermal Exposure: It may cause skin irritation in high concentrations. IFRA guidelines should be consulted for safe use in fragrances.
• Inhalation Exposure: As a volatile compound, inhalation exposure is possible, but it is generally considered safe at typical fragrance use levels. Occupational exposure limits are not specifically established.
• Risk Profiles: The risk profile is generally similar for both food and fragrance applications, with low toxicity at typical use levels.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

• Why This Material is Valuable: (E)-2-hexenal is prized for its ability to impart a fresh, green character to both flavors and fragrances.
• Typical Synergies: It blends well with other green and fruity notes, enhancing the overall freshness and authenticity of compositions.
• Common Formulation Pitfalls: Overuse can lead to an overly sharp or harsh aroma. Careful balancing with other notes is essential.
• Situations Where It is Frequently Over- or Under-Used: It is sometimes under-used in complex formulations where its impact can be masked by heavier notes.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

• Well-Established Data: The sensory profile and natural occurrence of (E)-2-hexenal are well-documented.
• Industry-Typical but Undocumented Practices: Use levels and formulation strategies are often based on industry experience rather than published data.
• Known Data Gaps or Regulatory Ambiguities: Specific ADI values and occupational exposure limits are not clearly reported.

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 2026-08-13 15:32:19 GMT (p2)