FlavScents AInsights Entry for (E)-2-hexenal (CAS: 6728-26-3)

1. Identity & Chemical Information

• Common Name(s): (E)-2-hexenal, Leaf Aldehyde
• IUPAC Name: (E)-hex-2-enal
• CAS Number: 6728-26-3
• FEMA Number: 3429
• Other Identifiers: FL No. 05.061
• Molecular Formula: C6H10O
• Molecular Weight: 98.15 g/mol

(E)-2-hexenal is an unsaturated aldehyde characterized by its alpha, beta-unsaturated carbonyl group, which contributes to its reactivity and sensory properties. The presence of the double bond in the (E)-configuration is crucial for its distinctive green, leafy odor, often associated with freshly cut grass or unripe fruits.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

(E)-2-hexenal is renowned for its potent green, leafy odor, reminiscent of freshly cut grass, green apples, and unripe fruits. It is a high-impact aroma compound with a strong, diffusive character. The odor threshold is relatively low, making it effective even at minimal concentrations. Its sensory role often includes providing freshness and a natural green note to flavor and fragrance compositions.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

(E)-2-hexenal is naturally found in a variety of plants and fruits, including apples, tomatoes, and green tea. It is typically formed through the enzymatic oxidation of linoleic acid, a common fatty acid in plant tissues. This compound is often associated with the "green" aroma of freshly cut plants and is a key component in the natural flavor and fragrance profiles of many fruits and vegetables.

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

4. Use in Flavors

(E)-2-hexenal is widely used in flavor formulations to impart a fresh, green note. It is commonly found in fruit flavors, particularly apple, pear, and tomato, as well as in vegetable and herbal flavors. Typical use levels in food and beverages range from 0.1 to 5 ppm, depending on the desired intensity and application. It is relatively stable under acidic conditions but can degrade under high heat or prolonged storage, necessitating careful formulation considerations.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

In the fragrance industry, (E)-2-hexenal is valued for its ability to add a fresh, natural green note to compositions. It is used in a variety of fragrance families, including floral, fruity, and green accords. Its volatility makes it a top note, contributing to the initial impression of a fragrance. Typical concentrations in perfumes and personal care products range from trace amounts to 0.5%, depending on the formulation and desired effect.

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 FL No. 05.061.
• United Kingdom: Follows EU regulations post-Brexit with no significant divergence reported.
• Asia: Approved for use in Japan and China, with specific concentration limits in certain applications.
• Latin America: Generally accepted under MERCOSUR regulations, with country-specific variations.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

For oral exposure, (E)-2-hexenal is considered safe at typical use levels, with an established ADI by FEMA. Dermal exposure in fragrances is generally safe, but it may cause irritation or sensitization in sensitive individuals, necessitating adherence to IFRA guidelines. Inhalation exposure is typically low risk due to its rapid volatility and low concentration in consumer products. Overall, the risk profiles are similar between food and fragrance applications, with appropriate safety margins in place.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

(E)-2-hexenal is prized for its ability to impart a fresh, green note, enhancing the naturalness of flavors and fragrances. It synergizes well with other green and fruity notes but can be overpowering if used excessively. Formulators should be cautious of its reactivity, particularly in complex systems, and consider encapsulation or stabilization techniques to preserve its integrity.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on (E)-2-hexenal is well-established, with comprehensive sensory and safety profiles documented in authoritative sources. While industry practices are generally consistent, some variability in regulatory interpretations may exist across regions. 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 2026-04-21 06:56:43 GMT (p2)