# Isobutyl Propionate

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**Safety rating:** UNKNOWN
**CAS number:** 540-42-1
**Category:** flavoring
**FDA GRAS:** no
**Adverse events (FDA AERS):** 0
**FDA recalls:** 0
**Last updated:** 2026-04-02

## Summary

Isobutyl propionate is a synthetic ester flavoring compound used to impart fruity, apple-like notes in food and beverage products. It is not approved as a food additive in the United States and is not included on the FDA's GRAS (Generally Recognized as Safe) list.

## Regulatory status

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

## Detailed analysis

## What is Isobutyl Propionate?

Isobutyl propionate (CAS Number 540-42-1) is a synthetic ester compound composed of isobutanol and propionic acid. It appears as a colorless to pale yellow liquid with a fruity aroma reminiscent of apples and other fruits. The compound is volatile at room temperature and is primarily used as a flavoring agent in the fragrance and food industries.

## Common Uses

When utilized as a food ingredient, isobutyl propionate serves as a flavoring agent designed to enhance or create fruity taste profiles in various food and beverage products. Its apple-like character makes it particularly suitable for applications in:

- Flavored beverages and soft drinks
- Confectionery products
- Baked goods
- Dairy products and desserts
- Flavor compounds and formulations

The compound is also used in the fragrance industry for cosmetic and non-food applications, where its fruity note contributes to overall scent profiles.

## Safety Assessment

Currently, there are no recorded adverse events associated with isobutyl propionate in the FDA's database, and no recalls involving this additive have been issued. This absence of reported incidents suggests a generally low toxicity profile when used in food applications.

As a synthetic ester, isobutyl propionate's safety profile is related to its chemical structure and metabolic fate. Esters in general are typically metabolized through hydrolysis in the digestive system, breaking down into their component alcohols and acids. Both isobutanol and propionic acid are individually recognized as food-safe components.

However, the lack of reported adverse events does not constitute formal FDA approval. Comprehensive toxicological studies on this specific compound would be necessary to establish definitive safety parameters, including acute toxicity, chronic exposure effects, and potential genotoxicity or carcinogenicity.

## Regulatory Status

Isobutyl propionate is notably absent from the FDA's GRAS (Generally Recognized as Safe) list, which means it has not undergone the formal evaluation process required for unrestricted use in food in the United States. The compound therefore operates outside the standard regulatory framework for approved food additives in America.

In the European Union, isobutyl propionate may have different regulatory standing through EFSA (European Food Safety Authority) evaluations, though it does not appear on standard EU approved flavoring lists in many jurisdictions. Its regulatory status varies significantly by country and region, reflecting different risk assessment approaches to flavoring compounds.

Manufacturers or importers wishing to use this additive in food products in the United States would need to pursue either a GRAS determination through qualified experts or file a food additive petition with the FDA for formal approval.

## Key Studies

Published scientific literature on isobutyl propionate is limited compared to more widely used food additives. The compound's chemical structure and properties suggest it would follow typical ester metabolism patterns observed in toxicological research on similar compounds. However, specific peer-reviewed studies focused exclusively on isobutyl propionate's safety in food applications are not readily available in major databases.

Future safety determinations would benefit from toxicological data including oral acute toxicity studies, repeated-dose studies, and genetic toxicity assessments. Additionally, metabolism and fate studies specific to this compound would provide valuable information for risk characterization in food use scenarios.

## 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. "Isobutyl Propionate — Safety, regulation, and evidence." https://additivefacts.com/additives/isobutyl-propionate. Accessed 2026-05-15.