What is 4-mercapto-2-pentanone?
4-mercapto-2-pentanone (CAS Number: 92585-08-5) is a volatile organic compound containing a thiol (sulfhydryl) functional group. The compound is a colorless to pale yellow liquid with characteristic sulfur-based aromatic properties. Its chemical structure consists of a five-carbon chain with a ketone group at position 2 and a thiol group at position 4, which are responsible for its distinctive sensory characteristics.
Common Uses
4-mercapto-2-pentanone is employed in the flavor industry as a flavoring agent and flavor adjuvant. It is used to create and enhance savory, meaty, roasted, and cooked notes in various food applications. The compound naturally occurs in foods including beef, cooked meat, roasted coffee, and certain fermented products. In industrial food production, it may be used in processed meat products, soups, broths, savory snacks, and other food items designed to have meaty or roasted flavor profiles. The extremely potent nature of this compound means it is used in very small quantities to achieve desired flavor effects.
Safety Assessment
According to FDA records, there are zero reported adverse events associated with 4-mercapto-2-pentanone and zero food recalls linked to this ingredient. The absence of adverse event reports suggests that the compound, when used at typical levels in food applications, has not been associated with consumer health complaints.
The thiol group in this molecule is structurally similar to compounds found naturally in foods like garlic and onions, which have a long history of safe consumption. However, the lack of FDA GRAS status indicates that the compound has not undergone the formal FDA safety assessment process that results in GRAS designation. GRAS status requires either extensive history of safe use before 1958 or documented scientific evidence of safety.
Limited published toxicological data is available for this specific compound. The safety profile of related mercaptan compounds has been studied, and most volatile sulfur compounds used in flavoring have demonstrated low systemic toxicity when used at appropriate concentrations. Occupational exposure data for workers in flavor production facilities indicates that inhalation of high concentrations may cause respiratory irritation, though food-level exposures are substantially lower.
Regulatory Status
4-mercapto-2-pentanone is not listed on the FDA's GRAS list. This means it cannot be presumed safe based on GRAS status in the United States. However, its absence from the GRAS list does not necessarily indicate unsafe use; rather, it indicates that the formal GRAS safety assessment has not been completed or submitted to the FDA.
The compound may be used in the United States if it is approved as a food additive through a Food Additive Petition (FAP) process, or if it meets other regulatory pathways. Regulatory status varies internationally; some jurisdictions may have different approval statuses or usage restrictions. The European Food Safety Authority (EFSA) maintains separate assessments and approval lists for flavoring agents used in the EU.
Key Studies
Published scientific literature on 4-mercapto-2-pentanone specifically is limited. Most safety information derives from general knowledge of thiol-containing flavor compounds and related sulfur-based volatiles. Studies on similar mercaptan compounds (such as 2-methyl-3-furanthiol and other roasted meat odorants) provide supporting information about compound class behavior.
Flavor industry organizations and research institutions have conducted analyses on the sensory potency and chemical stability of this compound, establishing its effectiveness at parts-per-billion concentrations. The natural occurrence of this compound in cooked foods has been documented through gas chromatography-mass spectrometry (GC-MS) analysis of meat and coffee volatiles, supporting the concept that humans have dietary exposure to this substance at low levels.
Further formal safety studies would be needed to support a GRAS petition or food additive approval with comprehensive toxicological data including acute toxicity, subchronic studies, and genotoxicity assessments.