FlavScents AInsights Entry for 2-Methyl Butyric Acid (CAS: 116-53-0)

1. Identity & Chemical Information

• Common Name(s): 2-Methyl butyric acid, Isovaleric acid
• IUPAC Name: 2-Methylbutanoic acid
• CAS Number: 116-53-0
• FEMA Number: 2693
• Other Identifiers: FL No. 08.005
• Molecular Formula: C5H10O2
• Molecular Weight: 102.13 g/mol

2-Methyl butyric acid is a branched-chain carboxylic acid characterized by its pungent odor. The presence of the methyl group at the second carbon contributes to its distinct odor profile, which is often described as cheesy or sweaty. This structural feature is crucial for its sensory impact in both flavor and fragrance applications.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

2-Methyl butyric acid is known for its strong, penetrating odor, often described as cheesy, sweaty, or reminiscent of rancid butter. It has a powerful, diffusive character that can be perceived at low concentrations. The taste is similarly intense, with a sour, acidic profile that can be overwhelming if not used judiciously. It serves as an impact note in formulations, providing a realistic background or modifying effect in complex flavor systems.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

2-Methyl butyric acid naturally occurs in various foods, including cheese, beer, and certain fruits. It is formed through the fermentation process, particularly in dairy products, where it contributes to the characteristic aroma of aged cheeses. Its presence in natural sources allows it to be designated as a "natural flavor" in certain regulatory contexts.

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

4. Use in Flavors

2-Methyl butyric acid is utilized in flavor formulations to impart a cheesy, fermented note. It is commonly used in dairy flavors, such as cheese and butter, as well as in savory applications. Typical use levels in food range from 0.1 to 5 ppm, depending on the desired intensity and the complexity of the flavor system. It is relatively stable under heat but can be sensitive to oxidation, requiring careful formulation to maintain its sensory properties.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

In fragrance applications, 2-methyl butyric acid is used to add a realistic, animalic note to compositions. It is found in fragrance families such as chypre and fougère, where it acts as a modifier or impact note. Typical concentrations are low, often below 0.1%, due to its potent odor. It contributes primarily to the middle notes of a fragrance, with moderate volatility.

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 No. 08.005.
• United Kingdom: Follows EU regulations post-Brexit.
• Asia: Approved for use in Japan and China, with specific restrictions in ASEAN countries.
• Latin America: Generally accepted, with specific regulations in Brazil and MERCOSUR countries.

Explicit approvals and harmonized assumptions are common, but formulators should verify country-specific regulations due to potential variability.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

For oral exposure, 2-methyl butyric acid is considered safe at typical flavor use levels, with an acceptable daily intake (ADI) established by relevant authorities. Dermal exposure in fragrance applications may cause irritation or sensitization, necessitating adherence to IFRA guidelines. Inhalation exposure is generally low risk due to its moderate volatility, but occupational safety measures should be observed in manufacturing settings.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

2-Methyl butyric acid is valued for its ability to impart a realistic, fermented note in both flavors and fragrances. It synergizes well with other dairy and savory notes but can easily overpower a formulation if used excessively. Common pitfalls include overuse, leading to an undesirable rancid character, and instability due to oxidation. It is often under-utilized in complex systems where subtlety is required.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on 2-methyl butyric acid is well-established, with comprehensive sensory and regulatory information available. Industry practices are well-documented, though some variability exists in regional regulatory interpretations. 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 2026-06-03 10:13:19 GMT (p2)