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

1. Identity & Chemical Information

• Common Name(s): Hexanal, Aldehyde C-6
• IUPAC Name: Hexanal
• CAS Number: 66-25-1
• FEMA Number: 2559
• Other Identifiers: FL No. 05.015
• Molecular Formula: C6H12O
• Molecular Weight: 100.16 g/mol

Hexanal is a saturated aliphatic aldehyde characterized by a six-carbon chain with a terminal aldehyde group. This structure is crucial for its odor profile, contributing to its grassy and green notes. The aldehyde functional group is responsible for its reactivity and volatility, which are significant in both flavor and fragrance applications.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

Hexanal is known for its distinctive grassy, green, and slightly fatty odor, reminiscent of freshly cut grass or unripe fruit. It is often described as having a moderate to high intensity with a sharp, penetrating character. The odor threshold of hexanal is relatively low, making it a potent impact note in formulations. In flavor applications, it is used to impart freshness and enhance the naturalness of fruit and vegetable profiles.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

Hexanal naturally occurs in a variety of plants and fruits, including apples, bananas, and tomatoes. It is formed through the oxidative degradation of linoleic acid, a common fatty acid in plant tissues. This process can occur during the ripening of fruits or when plant tissues are damaged, such as during cutting or crushing. Hexanal's presence in natural sources supports its designation as a "natural flavor" in regulatory contexts.

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

4. Use in Flavors

Hexanal is widely used in flavor formulations to provide fresh, green notes. It is commonly found in fruit, vegetable, and herbal flavor categories. Its functional role includes acting as an impact note and enhancing the authenticity of natural flavors. Typical use levels in finished food products range from 0.1 to 5 ppm, with higher concentrations used in more robust flavor profiles. Hexanal is relatively stable under acidic conditions but can degrade under high heat or prolonged exposure to air.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

In fragrance applications, hexanal is used to impart fresh, green, and aldehydic notes. It is a common component in the formulation of green and citrus fragrance families, often used in personal care products, household cleaners, and air fresheners. Hexanal typically contributes to the top notes of a fragrance due to its high volatility. Concentration ranges in fragrance formulations are generally low, often below 0.1%, to prevent overpowering other components.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

United States

Hexanal is approved for use as a flavoring agent under FEMA GRAS status. It is also recognized by the FDA as a safe substance when used in accordance with good manufacturing practices.

European Union

Hexanal is listed under Regulation (EC) No 1334/2008 with FL No. 05.015, allowing its use in food flavorings.

United Kingdom

Post-Brexit, the UK aligns with EU regulations regarding flavoring substances, maintaining similar approvals for hexanal.

Asia

In Japan, hexanal is permitted for use in food flavors, while in China and ASEAN countries, it is subject to local food safety standards, generally aligning with international norms.

Latin America

Countries like Brazil and those in MERCOSUR recognize hexanal under harmonized flavoring regulations, allowing its use in food products.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

Oral Exposure

Hexanal has a low acute toxicity profile when ingested, with an acceptable daily intake (ADI) not specifically established but considered safe under typical use conditions.

Dermal Exposure

In fragrance applications, hexanal is not a primary sensitizer but can cause irritation at high concentrations. IFRA guidelines provide usage limits to mitigate dermal risks.

Inhalation Exposure

Due to its volatility, inhalation exposure is possible, particularly in occupational settings. However, hexanal is not considered a significant inhalation hazard under normal use conditions.

Overall, the risk profiles for hexanal differ slightly between food and fragrance applications, primarily due to exposure routes and concentrations used.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

Hexanal is valued for its ability to impart fresh, green notes that enhance the naturalness of flavors and fragrances. It synergizes well with other aldehydes and green notes, but formulators should be cautious of its potency to avoid overpowering blends. Common pitfalls include using hexanal at too high a concentration, leading to an artificial or harsh character. It is often under-used in complex formulations where subtlety is required.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on hexanal is well-established, with comprehensive sensory and regulatory information available. Industry practices are well-documented, though some variability exists in use levels and sensory descriptions. 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 2026-01-26 12:40:37 GMT (p2)