FlavScents AInsights Entry for 2-Ethyl Butyric Acid (CAS: 88-09-5)

1. Identity & Chemical Information

• Common Name(s): 2-Ethyl butyric acid
• IUPAC Name: 2-Ethylbutanoic acid
• CAS Number: 88-09-5
• FEMA Number: 2458
• Other Identifiers: FL No. 09.034
• Molecular Formula: C6H12O2
• Molecular Weight: 116.16 g/mol

2-Ethyl butyric acid is a carboxylic acid characterized by its branched structure, which contributes to its distinctive odor profile. The presence of the ethyl group on the butyric acid backbone influences both its volatility and sensory characteristics, making it relevant in flavor and fragrance applications.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

2-Ethyl butyric acid is known for its pungent, cheesy, and slightly fruity odor, which can be perceived as unpleasant at high concentrations but adds complexity and authenticity to flavor compositions at lower levels. It is often described as having a sour, sweaty, and rancid note, contributing to its use as an impact note in certain flavor profiles. The odor threshold is relatively low, enhancing its potency in formulations.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

2-Ethyl butyric acid occurs naturally in various foods, including cheese and fermented products, where it is formed through microbial fermentation processes. It is also a byproduct of the breakdown of amino acids and fatty acids in these environments. Its presence in natural sources supports its designation as a "natural flavor" in certain regulatory contexts.

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

4. Use in Flavors

2-Ethyl butyric acid is utilized in flavor formulations to impart a cheesy, buttery, or fermented character. It is commonly used in dairy, savory, and some fruit flavors. Typical use levels in finished food products range from 0.1 to 5 ppm, depending on the desired intensity and application. It is stable under typical processing conditions but may degrade under extreme heat or acidic conditions.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

In fragrance applications, 2-ethyl butyric acid is used to add depth and authenticity to compositions, particularly in recreating natural scents such as cheese or fermented notes. It is often employed in trace amounts due to its potent odor. Its volatility contributes to its role as a top note, although it can also provide a lingering middle note in complex formulations.

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 an assigned FL number.
• United Kingdom: Aligns with EU regulations post-Brexit.
• Asia: Approved for use in Japan and China, with specific restrictions in some 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-ethyl butyric acid is considered safe at typical use levels, with an acceptable daily intake (ADI) established by relevant authorities. Dermal exposure in fragrance applications is generally low risk, but IFRA guidelines should be consulted to avoid irritation or sensitization. Inhalation exposure is minimal due to its low volatility, but occupational safety measures should be observed in manufacturing settings.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

2-Ethyl butyric acid is valued for its ability to impart authentic cheesy and fermented notes, enhancing the realism of dairy and savory flavors. It synergizes well with other fatty acids and esters. Formulators should be cautious of its potent odor, which can easily overpower a blend if overused. It is often underutilized in fruit flavors where subtle complexity is desired.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

Data on 2-ethyl butyric acid is well-established, with comprehensive sensory and regulatory information available. While industry practices are documented, some variability in natural occurrence data exists due to differing fermentation conditions. Regulatory ambiguities are minimal but should be monitored for updates.

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 2026-02-13 12:31:52 GMT (p2)