FlavScents AInsights Entry for Isobutyric Acid (CAS: 79-31-2)

1. Identity & Chemical Information

• Common Name(s): Isobutyric acid
• IUPAC Name: 2-Methylpropanoic acid
• CAS Number: 79-31-2
• FEMA Number: 2172
• Other Identifiers: FL No. 08.005, CoE No. 186
• Molecular Formula: C4H8O2
• Molecular Weight: 88.11 g/mol

Isobutyric acid is a carboxylic acid characterized by a branched structure, which contributes to its distinct sensory properties. The presence of the carboxyl group is crucial for its acidic nature and its role in flavor and fragrance applications.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

Isobutyric acid is known for its pungent, sour, and somewhat cheesy odor, often described as reminiscent of rancid butter or sweat. It has a strong, penetrating aroma with a high diffusion rate. The taste is similarly sour and unpleasant at higher concentrations, but it can provide a creamy, buttery note at lower levels. It is typically used as an impact note in flavor formulations.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

Isobutyric acid naturally occurs in various foods, including dairy products like cheese and butter, where it contributes to their characteristic flavors. It can also be formed through the fermentation of carbohydrates by certain bacteria. This compound is relevant to "natural flavor" designations when derived from natural sources or processes.

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

4. Use in Flavors

Isobutyric acid is used in flavor formulations to impart creamy, buttery, and cheesy notes. It is commonly found in dairy, savory, and some fruit flavors. Typical use levels in finished food products range from 0.1 to 10 ppm, depending on the desired intensity and application. It is relatively stable under normal processing conditions but can degrade under extreme heat or acidic conditions.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

In fragrances, isobutyric acid is used to add depth and realism to compositions, particularly in cheese and dairy accords. It is typically used in trace amounts due to its potent odor, contributing primarily to the top and middle notes. Its volatility is moderate, allowing it to blend well with other fragrance components.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

• United States: Recognized as GRAS by FEMA for flavor use.
• European Union: Approved under Regulation (EC) No 1334/2008 with FL number 08.005.
• United Kingdom: Follows EU regulations post-Brexit.
• Asia: Approved for use in Japan and China, with specific limits in ASEAN countries.
• Latin America: Generally accepted in Brazil and MERCOSUR countries, subject to local regulations.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

For oral exposure, isobutyric acid is considered safe at typical flavor use levels, with an acceptable daily intake (ADI) established by regulatory bodies. Dermal exposure in fragrance applications is generally low risk, but it can cause irritation in sensitive individuals. Inhalation exposure is minimal due to its low volatility in typical use concentrations. The risk profile is similar across food and fragrance applications.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

Isobutyric acid is valued for its ability to enhance creamy and buttery notes in both flavors and fragrances. It synergizes well with other dairy and savory compounds but can easily overpower a formulation if used excessively. Formulators should be cautious of its strong odor and potential for off-notes at higher concentrations.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on isobutyric acid is well-established, with comprehensive sensory and regulatory information available. Industry practices are well-documented, though some variability exists in natural occurrence data due to differences in source materials.

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 2026-03-31 12:34:39 GMT (p2)