FlavScents AInsights Entry for Propionic Acid (CAS: 79-09-4)
1. Identity & Chemical Information
Propionic acid, also known as propanoic acid, is a carboxylic acid with the IUPAC name Propanoic acid. It is identified by the CAS number 79-09-4. The FEMA number for propionic acid is 2924. Other identifiers include the FL number 08.005 and CoE number 18. The molecular formula of propionic acid is C3H6O2, and it has a molecular weight of 74.08 g/mol. Propionic acid contains a carboxyl group, which is responsible for its acidic properties and contributes to its pungent odor. The structure-odor relevance is significant as the carboxyl group imparts a sharp, sour smell that is characteristic of short-chain fatty acids.
Citation hooks: FlavScents; PubChem; FEMA
2. Sensory Profile
Propionic acid is characterized by a pungent, sour odor reminiscent of vinegar and a sharp, tangy taste. It is often described as having a cheesy, sweaty, or rancid note at higher concentrations. The odor threshold of propionic acid is relatively low, making it a potent sensory compound. In flavor applications, it serves as an impact note, providing a tangy, fermented character to food products. Its intensity and diffusion are high, requiring careful formulation to avoid overpowering other flavor components.
Citation hooks: FlavScents; peer-reviewed sensory literature
3. Natural Occurrence & Formation
Propionic acid naturally occurs in various foods, including cheese, butter, and fermented products, where it is produced by bacterial fermentation. It is also found in the human body as a metabolic intermediate. The formation of propionic acid in foods is often through the fermentation of carbohydrates by propionibacteria. This compound is relevant to the "natural flavor" designation as it can be derived from natural fermentation processes, aligning with consumer preferences for natural ingredients.
Citation hooks: FlavScents; food chemistry literature; EFSA/JECFA monographs
4. Use in Flavors
Propionic acid is used in a variety of flavor categories, including dairy, bakery, and savory applications. It functions as a flavor enhancer and preservative, contributing to the tangy, fermented notes in cheese and bread products. Typical use levels in finished food products range from 10 to 1000 ppm, with lower concentrations providing subtle acidity and higher levels imparting a more pronounced tang. Propionic acid is stable under typical food processing conditions, though it may volatilize at high temperatures.
Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature
5. Use in Fragrances
In fragrance applications, propionic acid is less commonly used due to its pungent odor. However, it can be found in trace amounts in certain fragrance compositions where it contributes to the realism of sweat or cheese notes. It is typically used in low concentrations, often below 0.1%, to avoid overpowering the fragrance blend. Propionic acid is highly volatile, contributing primarily to the top notes of a fragrance composition.
Citation hooks: FlavScents; IFRA; fragrance chemistry texts
6. Regulatory Status (Regional Overview)
In the United States, propionic acid is recognized as GRAS (Generally Recognized As Safe) by FEMA for flavor use. In the European Union, it is approved under Regulation (EC) No 1334/2008 and assigned the FL number 08.005. The United Kingdom follows similar regulations post-Brexit. In Asia, propionic acid is approved for use in Japan and China, with specific concentration limits in food applications. In Latin America, countries like Brazil and members of MERCOSUR also permit its use, aligning with international standards.
Citation hooks: FEMA; EFSA; national authority publications
7. Toxicology, Safety & Exposure Considerations
Propionic acid is considered safe for oral exposure at typical use levels in food, with an acceptable daily intake (ADI) established by regulatory authorities. Dermal exposure in fragrance applications is limited due to potential irritation, and it is not commonly used in leave-on products. Inhalation exposure is generally low, but occupational safety measures should be in place to minimize exposure in manufacturing settings. The risk profiles for food and fragrance applications differ, with stricter controls in place for dermal and inhalation routes.
Citation hooks: EFSA; FEMA; PubChem; toxicology literature
8. Practical Insights for Formulators
Propionic acid is valued for its ability to impart tangy, fermented notes in flavor formulations. It synergizes well with other acids and dairy flavors, enhancing the overall profile. Formulators should be cautious of its high volatility and potential to dominate a blend if used excessively. It is often under-used in fragrance applications due to its pungency, but when used judiciously, it can add authenticity to certain compositions.
Citation hooks: FlavScents; industry practice
9. Confidence & Data Quality Notes
The data on propionic acid is well-established, with comprehensive regulatory and sensory information available. Industry practices are documented, though some variability exists in use levels across different regions. Known data gaps are minimal, with most information supported by authoritative sources.
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
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 2026-02-16 19:39:18 GMT (p2)
