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 functional groups, which include an aldehyde group and a double bond in the trans configuration. This structure is crucial for its odor profile, contributing to its green, leafy scent reminiscent of freshly cut grass. The presence of the aldehyde group is significant for its reactivity and sensory impact.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

(E)-2-hexenal is known for its distinctive green, leafy odor, often described as fresh, grassy, and slightly fruity. It is a high-impact aroma compound with a strong intensity and moderate diffusion. The odor threshold is relatively low, making it effective even at minimal concentrations. It serves as an impact note in formulations, providing freshness and enhancing the perception of naturalness in both flavors and fragrances.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

(E)-2-hexenal is naturally found in a variety of plants, including apples, tomatoes, and green tea. It is formed through the enzymatic degradation of fatty acids, specifically linolenic acid, via the lipoxygenase pathway. 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

In flavor applications, (E)-2-hexenal is used to impart a fresh, green note to a wide range of products, including beverages, confectionery, and savory items. It is particularly valued in fruit flavors, where it enhances the perception of freshness and authenticity. Typical use levels in finished products range from 0.1 to 5 ppm, depending on the desired intensity and product type. It is relatively stable under acidic conditions but can degrade under high heat or prolonged storage.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

(E)-2-hexenal is utilized in fragrance formulations to provide a fresh, green top note. It is commonly found in perfumes, personal care products, and household cleaners. Its volatility makes it a top note, contributing to the initial impression of a fragrance. Typical concentrations range from trace amounts to 0.5% in the final product, depending on the desired effect and product type.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

In the United States, (E)-2-hexenal is recognized as GRAS (Generally Recognized As Safe) by FEMA for flavor use. In the European Union, it is listed under Regulation (EC) No 1334/2008 with FL No. 05.061. The UK follows similar regulations post-Brexit. In Asia, it is approved for use in Japan and China, with specific limits varying by country. In Latin America, it is generally accepted, but specific regulations may vary.

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 no specific ADI established but generally recognized as safe under FEMA GRAS. Dermal exposure in fragrance applications is monitored for potential irritation and sensitization, with IFRA providing guidelines to minimize risk. Inhalation exposure is generally low risk due to its volatility and rapid dispersion. Overall, the risk profiles are similar across food and fragrance applications, with standard safety practices recommended.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

(E)-2-hexenal is valued for its ability to impart a fresh, green note, enhancing the naturalness of both 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 formulations, and consider its volatility when designing products for long-term stability.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on (E)-2-hexenal is well-established, with comprehensive sensory and regulatory information available. Industry practices are well-documented, though some variability exists in regional regulatory interpretations. Known data gaps are minimal, primarily related to specific regional regulatory nuances.

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 2026-08-11 12:43:48 GMT (p2)