FlavScents AInsights Entry for Hexanal (Aldehyde C-6) (CAS: 66-25-1)

1. Identity & Chemical Information

Hexanal, commonly known as aldehyde C-6, is a volatile organic compound with the IUPAC name hexanal. It is identified by the CAS number 66-25-1. The FEMA number for hexanal is 2557. Other identifiers include the FL number 02.015 and CoE number 153. Hexanal has the molecular formula C6H12O and a molecular weight of 100.16 g/mol. It is an aliphatic aldehyde, characterized by a straight-chain structure that contributes to its distinctive grassy and green odor profile. The aldehyde functional group is crucial for its reactivity and sensory properties, making it a valuable component in flavor and fragrance formulations.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

Hexanal is known for its strong, penetrating odor reminiscent of freshly cut grass, green leaves, and unripe fruit. It is often described as having a green, aldehydic, and slightly fatty scent. The intensity of hexanal's odor is high, and it diffuses quickly, making it an effective impact note in formulations. While specific taste and odor thresholds are not always clearly reported, hexanal is typically used in low concentrations due to its potent sensory impact. It serves as an impact note and modifier, adding freshness and realism to both flavors and fragrances.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

Hexanal occurs naturally in a variety of plants and fruits, including apples, bananas, and tomatoes. It is also found in essential oils such as eucalyptus and peppermint. Hexanal is formed through the oxidative degradation of unsaturated fatty acids, particularly linoleic acid, via the lipoxygenase pathway. This process is common in plant tissues and contributes to the characteristic green notes in many natural products. Hexanal's presence in natural sources supports its designation as a "natural flavor" or "natural fragrance" component.

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

4. Use in Flavors

Hexanal is widely used in flavor formulations to impart fresh, green, and fruity notes. It is commonly found in fruit flavors, especially apple, pear, and citrus, as well as in vegetable and herbal flavors. Hexanal acts as an impact note and modifier, enhancing the authenticity and complexity of flavor profiles. Typical use levels in finished food or beverage products range from 0.1 to 5 ppm, with higher concentrations potentially leading to overpowering or off-notes. Hexanal is relatively stable under acidic conditions but can degrade under high heat or oxidative environments.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

In the fragrance industry, hexanal is utilized for its fresh, green, and aldehydic qualities. It is a key component in green, citrus, and floral fragrance families, contributing to the top notes of perfumes and personal care products. Hexanal serves as a trace realism and impact note, often used in concentrations ranging from 0.01% to 0.1% in formulations. Its high volatility makes it a prominent top note, providing an initial burst of freshness that quickly diffuses.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

In the United States, hexanal is recognized as Generally Recognized As Safe (GRAS) by FEMA for use in food flavors. In the European Union, it is approved under Regulation (EC) No 1334/2008 and assigned the FL number 02.015. The United Kingdom follows similar regulations post-Brexit. In Asia, hexanal is permitted in Japan and China, with specific use levels and applications subject to national regulations. In Latin America, countries like Brazil and those in MERCOSUR generally align with international standards, though specific approvals may vary.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

Hexanal's safety profile is well-documented for its intended uses. For oral exposure, it is considered safe within the established ADI and MSDI levels, with a wide margin of safety. Dermal exposure in fragrance applications is generally low-risk, though IFRA guidelines should be consulted to avoid irritation or sensitization. Inhalation exposure is minimal due to its rapid volatility, but occupational safety measures should be in place to prevent excessive inhalation in manufacturing settings. The risk profiles for food and fragrance applications are similar, with no significant differences noted.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

Hexanal is valued for its ability to impart freshness and realism to both flavors and fragrances. It synergizes well with other green and citrus notes, enhancing the overall sensory experience. Formulators should be cautious of its potency, as overuse can lead to overpowering or unpleasant notes. It is often under-used in complex formulations where subtlety is required. Hexanal's volatility should be considered in product development to ensure its impact is preserved in the final product.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on hexanal is well-established, with comprehensive documentation available from authoritative sources. Industry practices are generally consistent with documented guidelines, though some variability exists in use levels and applications. Known data gaps are minimal, with most regulatory and safety information 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 2026-06-02 16:40:09 GMT (p2)