1-BUTEN-1-YL METHYL SULFIDE

CAS: 32951-19-2 FLAVORING AGENT OR ADJUVANT

1-BUTEN-1-YL METHYL SULFIDE is a small organosulfur compound used as a flavoring agent in food formulations and evaluated by international food additive authorities with no safety concern at current intake levels when used as a flavouring agent.

What It Is

1-BUTEN-1-YL METHYL SULFIDE is a volatile organosulfur compound identified by the CAS number 32951-19-2 that belongs to a class of flavoring agents used in food and beverage formulations to impart specific savory or sulfurous odor nuances. It is recognized in flavor industry reference lists under FEMA number 3820 and JECFA number 457, indicating its role as a flavoring substance evaluated by food additive expert bodies. This class of compounds typically consists of small molecules containing sulfur groups that contribute intense odor characteristics, and the presence of a butenyl chain contributes both volatility and particular sensory attributes that are desirable in specific applications. As a technical function, it is categorized under ‘‘FLAVORING AGENT OR ADJUVANT," meaning it assists in enhancing or modifying the flavor profile of food products. The structure of 1-BUTEN-1-YL METHYL SULFIDE consists of a five-carbon backbone with a methyl sulfide moiety attached at the first carbon, creating a relatively small, low molecular weight molecule that is liquid at room temperature with a characteristic sulfurous odor that can influence sensory perception. The compound is typically handled as a liquid with specific handling considerations due to its odor and organosulfur properties. In regulatory and flavor industry nomenclature, the inclusion in FEMA and JECFA lists signifies that expert panels have considered its functional use and safety in flavor applications. However, the compound does not have an E-number assigned in the European Union list of food additives, reflecting that it is typically used at low concentrations as a flavoring substance rather than a bulk additive with a dedicated regulatory number.

How It Is Made

1-BUTEN-1-YL METHYL SULFIDE can be prepared through organic synthesis methods that involve introducing a methyl sulfide group onto a butene backbone. In general, synthetic routes for sulfur-containing flavor chemicals involve derivatization of olefins or alcohol precursors with sulfur nucleophiles under controlled conditions. The resulting product is then purified through distillation or chromatography to achieve suitable purity for use in flavor applications. Commercial production of this compound for use as a flavoring ingredient follows standard chemical manufacturing practices, involving reaction control to minimize impurities and careful handling due to its sulfurous character. Quality specifications for food grade flavoring substances like this one focus on ensuring that impurities that could affect odor or safety are controlled within defined limits. Although detailed proprietary manufacturing routes may vary by supplier, they often rely on classical organosulfur synthetic chemistry techniques that attach methyl sulfide functionalities to olefinic carbon chains. Because these compounds are typically used at trace levels in food, the production processes emphasize cost-effectiveness and reproducibility rather than large-scale bulk volumes. The purification processes aim to remove unreacted starting materials and byproducts to ensure the final product meets sensory and regulatory criteria for flavor use.

Why It Is Used In Food

1-BUTEN-1-YL METHYL SULFIDE is used in food products primarily as a flavoring agent to impart or enhance savory, sulfurous, or roasted notes that are characteristic of certain food categories. Flavor chemists select compounds like this to add depth and complexity to flavor profiles where subtle organosulfur notes can create a more authentic sensory perception, especially in savory or cooked products. The use of sulfur-containing flavor compounds, in general, is well established in flavor science because many naturally occurring foods develop sulfurous compounds during cooking or fermentation processes that contribute significantly to overall flavor. The inclusion of synthetic analogues or equivalents can help standardize these sensory attributes in processed foods, where natural variability may be too great. Because flavoring agents like 1-BUTEN-1-YL METHYL SULFIDE are highly potent, only very small amounts are typically used to achieve the desired effect. This economy of use supports targeted sensory goals without contributing significantly to the bulk composition of the food. In addition, these compounds are compatible with other flavor ingredients and can be blended to achieve specific sensory profiles demanded by product developers.

Adi Example Calculation

For flavoring agents that do not have a specific numeric ADI, an illustrative calculation can demonstrate how exposure compares with typical intakes in real-world scenarios. Suppose an adult weighing 70 kilograms consumes a product containing a flavor blend with a total of 10 micrograms of this compound per serving and has two servings per day; total intake would be 20 micrograms per day. Expressed on a body weight basis, this would equal approximately 0.00029 micrograms per kilogram body weight per day, which is orders of magnitude lower than typical exposure levels used in toxicological testing. This example is for illustration only and does not represent a recommended intake. Instead, it shows how low usage levels relative to body weight correspond to conservative safety evaluations by expert committees, where typical human exposure is much lower than doses that might elicit effects in experimental systems.

Safety And Health Research

Regulatory bodies assess the safety of flavoring agents like 1-BUTEN-1-YL METHYL SULFIDE by reviewing available toxicological studies, exposure estimates, and structure-activity relationships. For this compound, the JECFA evaluation concluded that there is no safety concern at current intake levels when used as a flavoring agent, which suggests that the available evidence did not indicate adverse effects at levels consistent with intended use. Safety assessments of flavoring substances typically consider endpoints such as genotoxicity, subchronic toxicity, and other relevant toxicological data to ensure that the compound does not pose unreasonable risks at anticipated exposure levels. The ‘‘no safety concern" conclusion reflects a weight-of-evidence approach where potential hazards are weighed against the low levels of human exposure typical for flavor use. It is important to note that JECFA’s evaluation focuses specifically on food-related exposure scenarios, and does not necessarily address other uses of the compound outside of flavoring contexts. The safety considerations documented by expert committees provide a basis for inclusion in flavor formulations, but ongoing monitoring and updates to evaluations can occur as new data become available.

Regulatory Status Worldwide

1-BUTEN-1-YL METHYL SULFIDE has been evaluated by international expert bodies for its use as a flavoring agent. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) evaluated this compound under JECFA number 457 and concluded that there is no safety concern at current levels of intake when used as a flavouring agent, reflecting a safety evaluation rather than a specific numeric acceptable daily intake. The JECFA evaluation is documented in the FAO/WHO Food Additives Series and related toxicological monographs. This evaluation supports its use in food at levels consistent with good manufacturing practice. In the United States, this compound is listed in the FDA’s Substances Added to Food database (formerly EAFUS) as 1-BUTEN-1-YL METHYL SULFIDE with the technical effect of a flavoring agent or adjuvant. However, there is no explicit CFR section granting a food additive regulation, and as such, direct approval status under 21 CFR sections is not clearly defined, resulting in an undefined approval field in regulatory summaries. Within the European Union, compounds used as flavoring substances follow enumeration and evaluation through the flavoring regulations, and the absence of an assigned E-number suggests this compound is not individually listed as an authorized food additive with a dedicated code but may be permitted as a flavoring under general provisions for flavoring substances that have been evaluated by expert committees such as JECFA.

Taste And Functional Properties

1-BUTEN-1-YL METHYL SULFIDE is characterized by a sulfurous, savory odor profile that can evoke roasted or alliaceous notes when perceived at low concentrations. The sensory impact of sulfur-containing compounds is well documented in flavor science, where even trace amounts can significantly influence the aroma and taste perception of complex food matrices. Functionally, the compound is volatile and has sufficient vapor pressure to contribute to aroma perception during eating or smelling. Its solubility properties in solvents like ethanol reflect typical behavior of small organosulfur compounds, which aids in formulation when blending with other flavor ingredients. Due to its potency, careful calculation of inclusion levels is critical to avoid overpowering other flavor elements. In practice, flavorists will experiment with very low usage rates, often at parts per million or even lower, to craft the intended sensory character. Its organosulfur nature also means it can interact with other volatile compounds, contributing synergistically to the overall flavor balance in complex formulas.

Acceptable Daily Intake Explained

An acceptable daily intake (ADI) is a concept used by food safety authorities to indicate a level of daily exposure that is considered safe over a lifetime, expressed per body weight. For many flavoring substances, including 1-BUTEN-1-YL METHYL SULFIDE, expert evaluations may conclude that there is no safety concern at expected intake levels rather than establishing a numeric ADI. This means that, based on available data and typical use concentrations, regulators have not identified a need for a specific numeric limit, provided the compound is used according to good manufacturing practice in food formulations. In practice, flavoring agents are used at very low concentrations, often far below levels where any toxicological effects might be expected, and the ‘‘no safety concern" conclusion from bodies such as JECFA reflects a margin of safety between typical use and levels that might raise concern in toxicological studies. This approach helps ensure consumer safety while allowing industry flexibility to use flavoring agents in appropriate applications.

Comparison With Similar Additives

Compared with other organosulfur flavoring agents, such as diallyl sulfide or methyl sulfide derivatives, 1-BUTEN-1-YL METHYL SULFIDE shares the characteristic of being potent at low concentrations and contributing distinctive sulfurous or savory notes. For example, diallyl sulfide, another sulfur-containing compound found in garlic and related flavors, also contributes strong aroma profiles in low concentrations. In contrast, many sulfur-containing compounds differ in volatility and odor thresholds, resulting in varying sensory impacts. Some organosulfur compounds may have stronger or more pungent characteristics, requiring even lower usage rates to avoid overpowering a flavor blend. Flavor chemists consider the relative potency and odor character of each compound when selecting them for specific formulations, balancing sensory contributions with stability and compatibility with other ingredients.

Common Food Applications Narrative

In everyday food products, 1-BUTEN-1-YL METHYL SULFIDE can be found as a component of savory flavor blends used in a range of processed and prepared foods. For example, it may be used in roasted nut flavor profiles, savory snack seasonings, or in complex sauce formulations where subtle sulfurous notes contribute to a richer sensory experience. Because sulfur compounds are often associated with cooked or roasted foods, formulators leverage this compound to enhance the authentic sensory impression in products where such characteristics are desirable. In beverage applications, low levels of this compound could be part of flavor packages designed to mimic the bouquet of roasted or cooked ingredients, although careful balancing is necessary due to the strong sensory impact of organosulfur molecules. Common categories where such flavor components may appear include savory snacks, seasonings for meat analogues, baked goods with rich aroma profiles, and specialty sauces where roasted undertones support consumer expectations. The inclusion of this compound in these products is typically at trace levels, and formulators combine it with a suite of other flavor molecules to achieve complex sensory profiles that are stable, reproducible, and compatible with processing conditions.

Safety & Regulations

FDA

  • Notes: No specific CFR food additive regulation identified in the FDA database for this compound.

EFSA

  • Notes: No specific E-number or numeric ADI identified in EFSA listings for this compound.

JECFA

  • Year: 1999
  • Adi Display: No safety concern at current levels of intake when used as a flavouring agent

Sources

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