FlavScents AInsights Entry for Propionaldehyde (CAS: 123-38-6)

1. Identity & Chemical Information

Propionaldehyde, also known as propanal, is a simple aldehyde with the molecular formula C3H6O and a molecular weight of 58.08 g/mol. Its CAS number is 123-38-6. The compound is characterized by the presence of an aldehyde functional group, which is crucial for its reactivity and sensory properties. The FEMA number for propionaldehyde is 2931. The structure of propionaldehyde, featuring a carbonyl group adjacent to a short alkyl chain, contributes to its distinctive odor profile, which is often described as pungent and fruity.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

Propionaldehyde is known for its sharp, pungent odor with fruity undertones, often compared to green apple or grass. It is a volatile compound with a high diffusion rate, making it an impactful top note in both flavors and fragrances. The odor threshold of propionaldehyde is relatively low, allowing it to be perceived at minimal concentrations. In flavor applications, it serves as an impact note, providing a fresh, aldehydic character that can enhance the realism of fruit and green notes.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

Propionaldehyde occurs naturally in various fruits and fermented products. It can be formed through the oxidation of propanol or as a byproduct of the Maillard reaction during the cooking of foods. Its presence in natural sources allows it to be used in formulations labeled as "natural flavor." The compound's formation through common biochemical pathways underscores its relevance in both natural and synthetic flavor systems.

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

4. Use in Flavors

In flavor applications, propionaldehyde is utilized across a range of categories, including fruit, dairy, and bakery flavors. It acts as a modifier and impact note, enhancing the freshness and authenticity of flavor profiles. Typical use levels in finished food products range from 0.1 to 5 ppm, depending on the desired intensity and the complexity of the flavor system. Propionaldehyde is relatively stable under acidic conditions but may degrade under high heat or oxidative environments, necessitating careful formulation considerations.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

Propionaldehyde is employed in fragrance formulations primarily for its top note contribution, providing a fresh, aldehydic lift to compositions. It is used in various fragrance families, including green, citrus, and floral. Typical concentration ranges in fragrance products are from trace amounts up to 0.5%, depending on the desired effect and product type. Its high volatility makes it suitable for applications where a quick, impactful scent is desired.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

In the United States, propionaldehyde is recognized as GRAS (Generally Recognized As Safe) by FEMA for flavor use. In the European Union, it is regulated under Regulation (EC) No 1334/2008 and has an assigned FL number. The regulatory status in the United Kingdom aligns with the EU post-Brexit. In Asia, including Japan and China, propionaldehyde is permitted for use in flavors, though specific regulations may vary. In Latin America, countries like Brazil follow MERCOSUR guidelines, which generally permit its use in flavors.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

Propionaldehyde's safety profile is well-documented for oral exposure, with an acceptable daily intake (ADI) established by regulatory bodies. For dermal exposure, it is considered a potential irritant, and its use in fragrances is subject to IFRA guidelines to prevent sensitization. Inhalation exposure is primarily a concern in occupational settings, where adequate ventilation and protective measures are recommended. The risk profiles for food and fragrance applications differ, with stricter controls typically applied in fragrance use due to potential skin contact.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

Propionaldehyde is valued for its ability to impart a fresh, aldehydic note that enhances the realism of fruit and green flavors. It synergizes well with other aldehydes and esters, providing a balanced and complex aroma profile. Formulators should be cautious of its volatility and potential for oxidation, which can lead to off-notes if not properly stabilized. It is often under-used in complex formulations where its impact can be masked by heavier components.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on propionaldehyde is well-established, with comprehensive sensory and regulatory information available. Industry practices are well-documented, though some formulation nuances may not be explicitly detailed in literature. Known data gaps are minimal, with most regulatory and safety aspects clearly defined.

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 2026-07-13 21:55:19 GMT (p2)