FlavScents AInsights Entry: Isopropyl Propionate (CAS: 637-78-5)

1. Identity & Chemical Information

• Common Name(s): Isopropyl propionate
• IUPAC Name: Propan-1-ol, 1-methylethyl ester
• CAS Number: 637-78-5
• FEMA Number: 2932
• Other Identifiers: FL No. 09.037
• Molecular Formula: C6H12O2
• Molecular Weight: 116.16 g/mol

Isopropyl propionate is an ester formed from isopropanol and propionic acid. The ester functional group is crucial for its characteristic fruity odor, which is often associated with pineapple and other tropical fruits. The molecular structure contributes to its volatility and sensory properties, making it a valuable component in both flavor and fragrance formulations.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

Isopropyl propionate is characterized by a fruity, pineapple-like odor with moderate intensity and good diffusion. It is often used as an impact note in flavor compositions, providing a fresh and tropical character. The odor threshold is relatively low, allowing it to be effective even at minimal concentrations. In flavor applications, it serves as a modifier to enhance the fruitiness of formulations.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

Isopropyl propionate is not commonly found in nature but can be synthesized through esterification of isopropanol and propionic acid. This reaction is typically catalyzed by acid and involves the removal of water to form the ester bond. While not naturally occurring, its synthetic production allows it to be used in "natural flavor" designations when derived from natural sources.

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

4. Use in Flavors

Isopropyl propionate is widely used in fruit flavor formulations, particularly those mimicking pineapple, apple, and other tropical fruits. It acts as a flavor enhancer and impact note, providing a fresh and juicy character. Typical use levels in finished food or beverage products range from 1 to 10 ppm, with higher concentrations potentially leading to an overpowering effect. It is stable under typical food 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, isopropyl propionate is used in fruity and tropical-themed perfumes and personal care products. It contributes to the top notes due to its high volatility, providing an initial burst of freshness. Typical concentration ranges in fragrance formulations are from 0.1% to 1%, depending on the desired intensity and product type. It is often used as a modifier to enhance the realism of fruit accords.

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 09.037.
• United Kingdom: Follows EU regulations post-Brexit.
• Asia: Approved for use in Japan and China, with specific concentration limits.
• Latin America: Generally accepted in Brazil and MERCOSUR countries, subject to local regulations.

Explicit approvals exist for flavor use, while fragrance applications are typically governed by industry standards such as IFRA guidelines.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

For oral exposure, isopropyl propionate is considered safe at typical use levels, with an acceptable daily intake (ADI) established by regulatory bodies. Dermal exposure in fragrance applications shows low irritation potential, but sensitization data is limited. Inhalation exposure is generally safe at typical fragrance concentrations, though occupational exposure should be monitored to prevent overexposure.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

Isopropyl propionate is valued for its ability to impart a fresh, fruity character to both flavors and fragrances. It synergizes well with other esters and fruity compounds, enhancing the overall profile. Formulators should be cautious of its volatility, which can lead to rapid evaporation if not properly encapsulated. It is often under-used in complex formulations where its impact could be beneficial.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on isopropyl propionate is well-established, with comprehensive sensory and regulatory information available. While industry practices are well-documented, some gaps exist in detailed toxicological studies, particularly regarding long-term exposure effects.

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
• No complex natural material section needed for this 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 2026-01-30 05:20:43 GMT (p2)