3-ACETYLMERCAPTOHEXYL ACETATE

CAS: 136954-25-1 FLAVORING AGENT OR ADJUVANT

**3-Acetylmercaptohexyl acetate** is a synthetic sulfur-containing ester used primarily as a **flavoring agent** characterized by a complex aroma profile with sulfurous, tropical fruit, and sweet notes. It has been evaluated by expert regulatory bodies for safety in flavor use and is listed under specified flavoring databases.

What It Is

3-Acetylmercaptohexyl acetate is an organic compound classified chemically as a sulfur-containing ester with the systematic name defined in the scientific literature and flavor ingredient registries. It is represented by the CAS number 136954-25-1, which uniquely identifies this molecular entity in chemical registries and regulatory inventories. Other systematic names attest to its chemical structure, including ethane­thioic acid, S-[1-(2-(acetyloxy)ethyl)butyl] ester and related synonyms that reflect the acetyl and mercapto functional groups attached to a hexyl backbone. This compound is part of a broader class of thioesters often used in the flavor and fragrance industries for their potent sensory impact and distinctive odor characteristics. Within flavoring ingredient compendia, such as the Flavor and Extract Manufacturers Association (FEMA) Flavor Library, this substance is indexed under FEMA number 3816 and has a JECFA (Joint FAO/WHO Expert Committee on Food Additives) evaluation number 494, indicating that it has been reviewed by international expert committees for safety when used as a flavoring agent in food products under defined conditions of use. The classification as a flavoring agent or adjuvant means it is used to impart, enhance, or modify aroma and taste attributes in a range of food and beverage formulations. The chemical structure of 3-Acetylmercaptohexyl acetate features a thioester linkage formed between an acetylmercapto moiety and an acetate ester group on a six-carbon aliphatic chain. The presence of sulfur in the structure contributes to its characteristic organoleptic properties, which include both fruity and sulfurous facets that can be perceived at trace levels in complex product matrices. Its functional role and sensory characteristics make it valuable in flavor formulations requiring nuanced tropical or savory notes when appropriately balanced with other ingredients.

How It Is Made

The synthesis of 3-Acetylmercaptohexyl acetate involves controlled organic chemical processes tailored to produce a high-purity flavor ingredient suitable for use in food and beverage applications. At a high level, manufacturing begins with a hexyl precursor that is chemically modified to introduce a mercapto functional group, which is subsequently acetylated. In typical synthetic pathways, a mercaptohexanol intermediate may be generated and then reacted with acetylating agents such as acetic anhydride or acetyl chloride under catalyzed conditions to form the desired thioester linkage. This strategy aligns with standard industrial practices for producing sulfur-containing esters, where careful control of reaction conditions helps minimize byproducts and maximize yield. Downstream purification steps such as distillation under reduced pressure, recrystallization, or chromatographic separation are employed to isolate the target compound from unreacted starting materials and trace impurities. The end product is a clear liquid with defined physicochemical properties that meet industry specifications for flavor use. Analytical techniques including gas chromatography and mass spectrometry are typically used in quality control to confirm identity and purity. Manufacturers producing flavor ingredients also adhere to Good Manufacturing Practices (GMP) and relevant quality standards that ensure consistency and safety for downstream food applications. Because the compound contains a sulfur moiety, special attention is paid during production to manage odor and handling considerations. Controlled ventilation and solvent recovery systems are standard in facilities that manufacture sulfur-containing esters to ensure worker safety and environmental compliance. Raw materials and intermediates are selected based on regulatory acceptability and compatibility with food-grade production if intended for flavor use. Overall, the synthesis of 3-Acetylmercaptohexyl acetate draws on established organic chemistry methods for esterification and acetylation, adapted for scale and regulatory requirements in flavor ingredient manufacturing. The end result is a well-characterized compound with reproducible sensory and functional attributes available for formulation by flavor chemists.

Why It Is Used In Food

3-Acetylmercaptohexyl acetate is incorporated into food and beverage formulations primarily for its aromatic and flavor-enhancing properties. Flavor chemists select this compound when specific sensory attributes such as subtle tropical fruit notes, exotic fruit nuances, or nuanced savory and sulfurous undertones are desired in a finished product. Its inclusion is intended to contribute complexity to a flavor profile and enhance the perception of other components within a blend. In practice, such sulfur-containing esters can add depth and character at very low concentrations, much lower than levels detectable by odor alone, but sufficient to influence overall sensory perception. The distinct aromatic signature of this compound includes a combination of metallic, fruity, and sulfurous facets that can complement fruit-forward profiles like passion fruit, mango, guava, and other exotic or citrus-like compositions. In these contexts, it helps create more rounded, authentic, or intensified tropical fruit impressions in beverages, confectionery items, dairy-based desserts, and other flavored products. It may also play a supporting role in savory flavor systems, where sulfurous notes help enhance the perception of meat or roasted characteristics when appropriately balanced. Formulators choose this additive with care, balancing it against other esters, aldehydes, and aroma compounds to achieve the desired flavor outcome without introducing overpowering or off-notes. Its use is governed by sensory thresholds and technical guidelines established by food chemists and regulatory bodies that oversee flavor ingredient applications. Because flavor perception is subjective and formulation-specific, the decision to use this compound in a particular food product arises from deliberate sensory evaluation and blending practices rather than broad categorical rules. Overall, the role of 3-Acetylmercaptohexyl acetate in food formulations is to contribute defined sensory nuances that enhance the consumer experience, enriching overall flavor complexity without altering the fundamental composition of the food beyond its aromatic contribution.

Adi Example Calculation

To illustrate how regulatory assessments like Acceptable Daily Intake (ADI) are used conceptually, consider a hypothetical scenario. Imagine that a flavoring ingredient were assigned an ADI of X milligrams per kilogram of body weight per day by an expert committee after thorough review of available data. For an adult weighing 70 kilograms, the ADI would be calculated by multiplying the ADI value by body weight. In this example, if ADI were X mg/kg body weight/day, then 70 kg multiplied by X yields a total allowable intake of 70 times X milligrams per day. This hypothetical calculation helps illustrate how regulators frame safety benchmarks with built-in margins of safety. This type of calculation helps put exposure into perspective: because flavoring agents are used at very low concentrations in food products, actual consumer exposure is typically orders of magnitude below such hypothetical benchmarks. It also demonstrates that ADI is a regulatory concept used to support informed decisions about ingredient use rather than a daily target. It is important to underscore that this calculation is illustrative and not specific to 3-Acetylmercaptohexyl acetate, as precise numeric ADI values require direct evidence from authoritative regulatory evaluations. When such numerical values are not explicitly provided in evidence databases, the corresponding fields remain null and narrative explanations focus on general safety evaluation principles.

Safety And Health Research

Regulatory and scientific bodies evaluate flavoring ingredients like 3-Acetylmercaptohexyl acetate by reviewing available toxicological and exposure data to determine whether use at typical levels poses safety concerns. Expert committees such as the Joint FAO/WHO Expert Committee on Food Additives (JECFA) assess a range of toxicological endpoints, including general toxicity, genotoxicity, and potential effects on organ systems, drawing on published studies and industry-provided data. In its evaluation for JECFA number 494, this compound was concluded to raise no safety concern at current levels of intake when used as a flavoring agent, based on the available scientific evidence. Such evaluations typically consider both hazard identification and exposure assessment. Hazard identification involves understanding the intrinsic properties of the substance and its potential to cause adverse effects, while exposure assessment estimates the levels to which consumers may be exposed through normal dietary intake. For flavor ingredients, exposure is often low because of the potent nature of many aromatic compounds, which are used at trace concentrations in formulations. Independent expert panels also examine data on metabolism and elimination, seeking to understand how the compound is processed in the body. Many flavor compounds are metabolized and excreted relatively rapidly, reducing the potential for accumulation. However, flavor ingredient evaluations are constrained by the availability of data; for many substances in this class, comprehensive long-term studies may be limited, and conclusions are drawn from a combination of available evidence and established analogues. Overall, safety assessments for flavoring agents like 3-Acetylmercaptohexyl acetate emphasize a weight-of-evidence approach, integrating chemical structure, toxicological data, and estimated intake levels to determine whether typical dietary exposure poses a concern. These assessments inform regulatory listings and provide a basis for use-level guidance in food and beverage applications.

Regulatory Status Worldwide

Regulatory oversight for flavoring ingredients such as 3-Acetylmercaptohexyl acetate differs across jurisdictions and is based on expert safety evaluations by recognized bodies. This compound is included in specialized flavor ingredient inventories rather than broad additive lists, reflecting its technical function as a flavoring agent or adjuvant rather than a traditional food additive. In the United States, it is listed in the Flavor and Extract Manufacturers Association (FEMA) Flavor Library under FEMA number 3816, indicating that it has been evaluated by a panel of flavor experts for general recognition as safe (GRAS) under stated conditions of intended use. The FEMA Flavor Library is submitted to the U.S. Food and Drug Administration (FDA) for inclusion in the Substances Added to Food inventory, which tracks flavoring substances and their safety assessments. However, inclusion in this inventory does not equate to explicit FDA approval under specific Code of Federal Regulations (CFR) sections; rather, it indicates that the substance is recognized for use as a flavoring agent with established safety considerations under customary use levels. At the international level, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) has evaluated 3-Acetylmercaptohexyl acetate (JECFA number 494) and concluded that there is no safety concern at current levels of intake when used as a flavoring agent according to its evaluation, reflecting international expert review of available toxicological and exposure data. JECFA evaluations inform global regulatory frameworks and help harmonize safety assessments across regions. In jurisdictions outside the United States, national food safety authorities often reference JECFA and FEMA evaluations as part of their own risk assessment processes for flavor ingredients, applying similar use-level constraints to ensure consumer safety. Inclusion in flavor ingredient inventories and authoritative safety assessments by expert committees helps provide a context for responsible use in food and beverage products while guiding regulatory compliance for manufacturers operating in multiple markets.

Taste And Functional Properties

3-Acetylmercaptohexyl acetate exhibits distinctive sensory and functional properties that influence its behavior in flavor applications. This sulfur-containing ester is recognized for its potent and complex aroma profile, which may include elements described as fruity, tropical, sweet, and sulfurous when perceived by trained sensory panels. The sensory impact of this compound is highly concentration-dependent: at trace levels, it can impart nuanced character that enhances the perception of other fruit or tropical notes, while at higher concentrations its sulfurous facets may become more pronounced. Chemically, the presence of a thioester functional group increases the compound’s potency in olfactory terms compared with simple oxygen-containing esters. The sulfur atom contributes to the perception of “sulfurous” or “savory” notes that can evoke tropical fruits such as passion fruit, which naturally contain certain sulfur compounds. This makes it valuable in flavor systems that aim to mimic or enhance exotic fruit profiles. When used in balanced formulations, it may also help accentuate other esters and aldehydes, creating a more layered aroma experience. From a functional perspective, 3-Acetylmercaptohexyl acetate has limited water solubility and is more soluble in organic solvents such as ethanol or glycerol, which are common diluents in flavor stocks. Its relatively low volatility compared to lighter esters means it may provide sustained aroma release in flavor applications, contributing to persistence in the aroma profile without dissipating too rapidly. These characteristics make it suitable for liquid and encapsulated flavor systems where controlled release is desirable. The compound’s stability under typical food processing conditions, including moderate heat and pH ranges encountered in many beverage and confectionery applications, enhances its utility. However, formulators must consider interactions with other ingredients, as sulfur-containing components can react under extreme conditions, potentially altering sensory attributes. Overall, the sensory and functional properties of 3-Acetylmercaptohexyl acetate make it a specialized ingredient applied selectively by flavor scientists to achieve targeted aromatic profiles.

Acceptable Daily Intake Explained

The concept of an Acceptable Daily Intake (ADI) is central to understanding how regulatory bodies manage the safety of flavoring ingredients like 3-Acetylmercaptohexyl acetate. An ADI represents an estimate of the amount of a substance that can be consumed daily over a lifetime without posing appreciable health risk, based on comprehensive toxicological data and extensive expert evaluation. It is typically expressed in terms of milligrams per kilogram of body weight per day and includes substantial safety factors to account for uncertainties and variation in human populations. For many flavoring agents, including this compound, expert committees such as the Joint FAO/WHO Expert Committee on Food Additives (JECFA) conduct thorough evaluations of available toxicological studies before establishing an ADI or concluding that there is no safety concern at current levels of intake. In the case of 3-Acetylmercaptohexyl acetate, the JECFA evaluation concluded that use as a flavoring agent at levels typical of flavor formulations is not of safety concern. This type of conclusion is informed by scientific assessments that take into account exposure estimates and potential effects observed in experimental systems. It is important to note that the ADI is not a target or recommended consumption level but a regulatory benchmark that helps guide safe use. Actual dietary exposure to a given flavoring agent by consumers is generally much lower than the ADI, reflecting the small quantities at which potent flavor compounds are used in food products. Regulatory frameworks use this information to set use-level guidance, ensuring that the aggregate intake from multiple sources remains within safe limits. By framing safety in terms of ADI and expert evaluations, regulatory bodies provide a science-based approach that balances the functional utility of flavoring agents with caution to protect public health, relying on conservative assumptions and safety margins to address uncertainty.

Comparison With Similar Additives

Flavor chemists often compare compounds with similar functional roles to understand their respective sensory contributions and technical behavior. For example, oxygen-containing esters such as ethyl acetate and isoamyl acetate are widely used in fruit flavor formulations for their characteristic sweet, fruity notes. These compounds are relatively simple esters with limited sulfur character, contributing broadly familiar fruit aromas at low concentrations and are commonly found in fruit-flavored beverages, baked goods, and confectionery products. In contrast, sulfur-containing esters like 3-Acetylmercaptohexyl acetate bring a different dimension to a flavor profile, offering more complex aromatic notes that can suggest tropical or exotic fruit nuances not easily achieved with simple esters alone. Another similar class of additives includes other thioesters such as 3-mercaptohexyl acetate (FEMA number 3851), which contribute distinctive passion fruit or tropical notes and are used in specialized flavor systems. While both compounds share sulfur in their structure, their specific odor profiles and potency differ, with 3-Acetylmercaptohexyl acetate often used where a balance between sulfurous and fruity character is desired, complementing other esters and aroma compounds in complex blends. Formulators also consider factors such as volatility, solubility, and interaction with other ingredients when selecting between different esters. Simple esters with higher volatility may contribute to top notes in a flavor profile, while more persistent, less volatile compounds like sulfur-containing thioesters provide depth and continuity in the aroma experience. Understanding these differences helps flavor scientists design products that meet sensory objectives while aligning with regulatory guidance.

Common Food Applications Narrative

In the world of flavored foods and beverages, 3-Acetylmercaptohexyl acetate is a niche yet impactful ingredient used by flavor chemists to craft nuanced sensory experiences. This compound finds application in products where subtle tropical or exotic fruit notes enhance overall flavor perception. For example, it may be included in tropical fruit beverages designed to replicate passion fruit, guava, or mango profiles, where its sulfurous yet fruity aroma complements other esters and aldehydes to produce a more authentic and memorable taste impression. In dairy-based desserts and frozen treats, flavorists may employ this ingredient to enrich fruit-forward compositions, helping round out the aromatic complexity in combination with other flavoring agents. Its ability to contribute layered notes without dominating the sensory profile makes it suitable for confectionery applications as well, where it can enhance fruit candy flavors or exotic fruit fillings. Similarly, in certain bakery applications, especially those featuring fruit-flavored icings or glazes, it may play a supporting role in creating depth and richness in the aroma bouquet. Beyond fruit flavors, the compound’s nuanced sulfurous characteristics can add dimensions to savory notes in complex flavor systems, though such use requires careful balancing to avoid overpowering other components. In ready-to-drink mixers and flavored alcohol products, where tropical fruit essences are commonplace, this ester can subtly elevate the overall profile when blended within a broader flavor matrix. Across these applications, food scientists rely on precise dosing informed by sensory evaluation to ensure the desired effect is achieved without introducing undesired off-notes. Importantly, the decision to include 3-Acetylmercaptohexyl acetate in a product is driven by sensory goals and regulatory compliance with flavor usage guidelines rather than mandatory requirements. As with all flavor ingredients, it is one tool among many that formulators may use to achieve specific aromatic and taste objectives in consumer products.

Safety & Regulations

FDA

  • Notes: Inclusion in flavoring inventories such as FEMA and the FDA Substances Added to Food inventory does not constitute formal FDA approval under specific CFR sections.

EFSA

  • Notes: No direct evidence found for an EFSA specific ADI or E-number for this compound.

JECFA

  • Notes: JECFA evaluation concluded no safety concern but did not explicitly assign a numeric ADI value.
  • Adi Display: No safety concern at current levels of intake when used as a flavouring agent

Sources

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