FlavScents AInsights Entry for (E)-2-methyl-2-pentenoic acid (CAS: 16957-70-3)

1. Identity & Chemical Information

• Common Name(s): (E)-2-methyl-2-pentenoic acid
• IUPAC Name: (E)-2-methylpent-2-enoic acid
• CAS Number: 16957-70-3
• FEMA Number: Not available
• Other Identifiers: Not available
• Molecular Formula: C6H10O2
• Molecular Weight: 114.14 g/mol

(E)-2-methyl-2-pentenoic acid is characterized by its unsaturated carboxylic acid functional group. The presence of the double bond in the (E)-configuration contributes to its distinct odor profile, which is relevant in both flavor and fragrance applications.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

(E)-2-methyl-2-pentenoic acid is known for its pungent, sour odor with a hint of fruitiness. It is often described as having a sharp, penetrating aroma that can be perceived at low concentrations. The compound's sensory role is typically as an impact note, providing a distinctive character to formulations. Specific odor and taste thresholds are not clearly reported in the literature, but its strong odor suggests a low threshold.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

(E)-2-methyl-2-pentenoic acid is not widely reported as a natural constituent in foods or essential oils. It may form through the degradation of certain fatty acids or as a byproduct of fermentation processes. Its presence in natural products is limited, which affects its designation as a "natural flavor" or "natural fragrance" component.

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

4. Use in Flavors

In flavor applications, (E)-2-methyl-2-pentenoic acid is used to impart a sharp, tangy note, often in fruit or dairy flavors. It can enhance the authenticity of certain flavor profiles by adding a sour, acidic edge. Typical use levels in finished food products are not well-documented, but industry practices suggest usage in the low ppm range due to its potent aroma. Stability under heat and acidic conditions is generally good, but it may be prone to oxidation.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

(E)-2-methyl-2-pentenoic acid is utilized in fragrance formulations to provide a fresh, sour note that can enhance the realism of fruity or green accords. It is typically used in trace amounts due to its strong odor. The compound contributes primarily to the top notes of a fragrance, given its volatility. Concentration ranges are generally qualitative, with usage at very low levels to avoid overpowering other components.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

• United States: Not explicitly listed as FEMA GRAS; usage should comply with general safety guidelines.
• European Union: Not specifically listed under Reg. (EC) No 1334/2008; assumed to be allowed under general flavoring principles.
• United Kingdom: Follows EU regulations post-Brexit with no specific divergence reported.
• Asia: Limited specific information; general safety and usage guidelines apply.
• Latin America: No specific regulatory listings; usage should align with general safety standards.

Explicit approvals are limited, and formulators should verify compliance with local regulations.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

For oral exposure, specific ADI or MSDI values for (E)-2-methyl-2-pentenoic acid are not available. It is generally considered safe when used at low levels typical for flavor applications. Dermal exposure in fragrance use should be approached with caution due to potential irritation or sensitization, although specific IFRA guidelines are not available. Inhalation exposure is primarily a concern for occupational settings, where adequate ventilation should be ensured.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

(E)-2-methyl-2-pentenoic acid is valued for its ability to impart a sharp, tangy note that can enhance the authenticity of flavor and fragrance profiles. It synergizes well with fruity and green notes but should be used sparingly to avoid overpowering other components. Common pitfalls include overuse, leading to an undesirable sourness. It is often under-utilized in formulations seeking a fresh, acidic character.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on (E)-2-methyl-2-pentenoic acid is limited, with much of the information derived from industry practices rather than peer-reviewed studies. Regulatory and safety data are not comprehensive, highlighting the need for formulators to exercise caution and verify compliance with local regulations.

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
• Section 5a is not applicable as this is a single compound

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 2026-02-25 13:56:17 GMT (p2)