# Propyl Isobutyrate

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> Markdown URL: https://additivefacts.com/additives/propyl-isobutyrate.md

**Safety rating:** UNKNOWN
**CAS number:** 644-49-5
**Category:** flavoring
**FDA GRAS:** no
**Adverse events (FDA AERS):** 0
**FDA recalls:** 0
**Last updated:** 2026-04-04

## Summary

Propyl isobutyrate is a synthetic ester compound used as a flavoring agent in food products. It provides fruity, buttery, and dairy-like aromatic notes and is employed in beverages, confectionery, and other processed foods to enhance or create desired flavor profiles.

## Regulatory status

| Country | Status |
| --- | --- |
| United States | approved |
| European Union | not_evaluated |
| United Kingdom | approved |
| Canada | approved |
| Australia | approved |
| Japan | approved |
| South Korea | approved |
| Brazil | approved |
| China | approved |
| India | approved |

## Detailed analysis

## What is Propyl Isobutyrate?

Propyl isobutyrate (CAS Number 644-49-5) is a synthetic ester belonging to the family of organic compounds used in food flavoring applications. It is derived from propionic acid combined with isobutanol through esterification. This colorless to pale yellow liquid possesses a characteristic fruity and buttery aroma, making it valuable in the flavor chemistry industry for creating complex taste and smell experiences in food and beverage products.

## Common Uses

Propyl isobutyrate is primarily used as a flavoring agent in various food categories. Its applications include:

- Beverages: soft drinks, flavored waters, and juice-based products
- Confectionery: candies, chewing gums, and hard candies
- Dairy products: flavored milks and yogurt formulations
- Baked goods: cookies, pastries, and cake flavorings
- Processed foods: snacks and other consumer products requiring flavor enhancement

The compound typically appears in formulations at very low concentration levels, contributing to the overall flavor profile without serving as a primary ingredient. Its fruity and dairy notes make it particularly useful in applications attempting to simulate natural fruit or dairy flavors.

## Safety Assessment

Propyl isobutyrate has not been designated as Generally Recognized as Safe (GRAS) by the FDA, indicating that it has not undergone the formal GRAS notification process. However, this classification does not necessarily indicate a safety concern; rather, it reflects the regulatory pathway taken by manufacturers and the extent of safety documentation submitted to regulatory authorities.

Available safety data presents a neutral profile:

- The FDA has recorded zero adverse events associated with propyl isobutyrate
- No food recalls have been linked to this additive
- Toxicological data on the compound suggests low acute toxicity
- The ester structure is consistent with other approved food flavoring esters

As a synthetic flavoring compound, propyl isobutyrate is used at levels far below those tested in toxicological studies. The acceptable daily intake (ADI) and safety margins established through testing provide reasonable assurance of safety at intended use levels, consistent with established food safety principles for flavoring agents.

## Regulatory Status

The regulatory landscape for propyl isobutyrate varies by jurisdiction:

- **United States**: Not listed as GRAS by the FDA; its use may be permitted under specific regulatory pathways or as part of flavor formulations from GRAS-listed flavor suppliers
- **European Union**: Listed in the Register of Flavoring Substances; permitted for use in food products under Regulation (EC) 1334/2008
- **Other jurisdictions**: Authorized in various countries with established flavor compound approval processes

Manufacturers utilizing propyl isobutyrate must ensure compliance with local regulations and maintain appropriate documentation for regulatory authorities. The absence of GRAS status in the US does not prohibit use but requires manufacturers to follow appropriate regulatory compliance procedures.

## Key Studies

Toxicological research on propyl isobutyrate and structurally similar esters has demonstrated:

- Low oral toxicity in animal models
- No significant genotoxic or mutagenic potential
- Rapid metabolism consistent with other short-chain esters
- No bioaccumulation in animal tissues

The safety profile of propyl isobutyrate aligns with that of other approved food-grade ester flavorings, which have been used in food products for decades without documented safety issues at intended use levels. Continued monitoring through existing food safety surveillance systems remains appropriate, as with all food additives.

## Sources

- FDA Substances Added to Food (CFSAN)
- OpenFDA Adverse Event Reporting System (AERS)
- OpenFDA Food Recalls
- EFSA OpenFoodTox
- EU Food Additive Portal

## Citation

Additive Facts. "Propyl Isobutyrate — Safety, regulation, and evidence." https://additivefacts.com/additives/propyl-isobutyrate. Accessed 2026-05-20.