FlavScents AInsights Entry: Acetaldehyde (CAS: 75-07-0)

1. Identity & Chemical Information

• Common Name(s): Acetaldehyde
• IUPAC Name: Ethanal
• CAS Number: 75-07-0
• FEMA Number: 2003
• Other Identifiers: FL No. 02.001
• Molecular Formula: C₂H₄O
• Molecular Weight: 44.05 g/mol
• Functional Groups and Structure–Odor Relevance: Acetaldehyde is an aldehyde with a carbonyl group (C=O) that contributes to its pungent, fruity odor. This functional group is crucial for its reactivity and sensory characteristics, making it a significant impact compound in flavor and fragrance formulations.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

Acetaldehyde is characterized by a sharp, pungent odor with fruity and green nuances. It is often described as having a fresh, apple-like aroma, which can be intense and diffusive. The compound serves as an impact note in flavor compositions, providing a crisp, fresh top note that enhances the perception of freshness and juiciness in fruit flavors. Its odor threshold is relatively low, making it effective even at minimal concentrations.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

Acetaldehyde occurs naturally in various fruits, such as apples, grapes, and citrus, and is a byproduct of fermentation processes. It is formed through the enzymatic oxidation of ethanol by alcohol dehydrogenase and can also result from the Maillard reaction during food processing. Its presence in natural products allows it to be designated as a "natural flavor" under certain regulatory frameworks.

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

4. Use in Flavors

Acetaldehyde is widely used in flavor formulations, particularly in fruit flavors such as apple, citrus, and berry. It acts as an impact note, providing freshness and enhancing the overall flavor profile. Typical use levels in finished food products range from 1 to 50 ppm, with higher concentrations potentially leading to an overpowering or harsh taste. Acetaldehyde is sensitive to oxidation and can react with other flavor components, necessitating careful formulation to maintain stability.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

In fragrance applications, acetaldehyde is used to impart a fresh, green, and fruity top note. It is commonly found in citrus and floral fragrance families, where it serves as a modifier or impact note. Typical concentrations in fragrance formulations are low, often below 0.1%, due to its high volatility and potential for rapid evaporation. Its contribution is primarily in the top note phase, providing an initial burst of freshness.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

• United States: Acetaldehyde is recognized as GRAS (Generally Recognized As Safe) by FEMA for flavor use.
• European Union: Listed under Regulation (EC) No 1334/2008 with FL No. 02.001, allowing its use in food flavorings.
• United Kingdom: Post-Brexit regulations align with EU standards for flavor use.
• Asia: In Japan, acetaldehyde is permitted for use in food flavors, while China and ASEAN countries have specific guidelines for its use.
• Latin America: Brazil and MERCOSUR countries recognize acetaldehyde under regional flavor regulations.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

Acetaldehyde's safety profile varies with exposure route. For oral exposure, it is considered safe at low concentrations typical in food flavors, with an ADI not clearly established but generally accepted under GRAS status. Dermal exposure in fragrances may cause irritation or sensitization, necessitating adherence to IFRA guidelines. Inhalation exposure, particularly in occupational settings, requires caution due to its volatility and potential respiratory irritation. Risk profiles differ between food and fragrance applications, with stricter controls in place for inhalation and dermal exposure.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

Acetaldehyde is valued for its ability to impart freshness and enhance fruitiness in both flavors and fragrances. It synergizes well with other aldehydes and esters, but formulators must manage its reactivity and volatility. Common pitfalls include overuse, leading to harshness, and instability due to oxidation. It is often under-used in complex formulations where its impact can be masked by other components.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

Data on acetaldehyde is well-established, with comprehensive sensory and regulatory information available. Industry practices are documented, though some variability exists in regional regulatory interpretations. Known data gaps include specific ADI values and detailed inhalation 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 2026-04-09 21:25:55 GMT (p2)