2-CYCLOHEXENONE

CAS: 930-68-7 FLAVORING AGENT OR ADJUVANT

2-CYCLOHEXENONE is a cyclic ketone used as a flavouring agent with a glycidic aroma profile. It is evaluated by international expert bodies for use as a flavouring substance under intended conditions of use and appears in the flavor ingredient libraries of industry panels and JECFA evaluations. Its safety has been discussed in expert evaluations but precise regulatory numeric limits are not established in standard additive regulations.

What It Is

2-CYCLOHEXENONE is a small organic compound structurally defined as a cyclohexene ring bearing a ketone functional group. Its International Chemical Abstracts Service (CAS) number is 930-68-7, and it is recognized under other names including 2-CYCLOHEXEN-1-ONE and 2-CYCLOHEXENONE. This chemical falls into the class of flavoring agents, compounds used to impart or modify aroma and taste in food products, and its technical function in foods is typically as a flavouring adjunct rather than a bulk ingredient. As a flavouring agent, it contributes specific sensory notes that are often described in industry libraries, and it is considered in safety evaluations by expert committees. Compounds like 2-CYCLOHEXENONE belong to a broader category of enones, which are characterized by the conjugation between a carbon-carbon double bond and a carbonyl group, giving them distinctive sensory and chemical properties. In the flavour industry, such molecules are often used at low levels to add complexity to aromatic profiles in a range of products. The designation as a flavoring agent reflects its intended use to influence aroma in food formulations, and this role is well established in specialized flavor ingredient references maintained by organizations such as FEMA and in safety evaluations by international bodies such as the Joint FAO/WHO Expert Committee on Food Additives (JECFA).

How It Is Made

The manufacture of 2-CYCLOHEXENONE involves classical organic chemistry transformations. In industrial and chemical synthesis contexts, the compound is commonly produced via oxidation of cyclohexene or dehydration of precursor alcohols under controlled conditions. These processes yield a cyclic ketone with moderate purity that can be further refined for specific applications including flavour use. In a generic synthesis route, an intermediate such as cyclohexene is subjected to oxidative conditions that introduce the carbonyl functionality at a specific position on the ring. Alternatively, a corresponding cyclohexenol can be dehydrated to form the enone system, which provides the structural basis for the flavouring molecule. These reactions are typical of many ketone and enone syntheses and are implemented with standard organic reagents in commercial chemical production. After synthesis, the crude material is usually subjected to purification steps such as distillation and solvent washes to achieve a specification suitable for flavour applications. The purity and impurity profiles are important considerations for any compound intended for food use, as residual reagents or by-products can significantly impact both safety and sensory outcomes. Purification methods ensure that the final material meets appropriate industry standards and is free from contaminants that might interfere with its intended function as a flavouring agent.

Why It Is Used In Food

2-CYCLOHEXENONE is used in food primarily because of its ability to influence the aroma profile of a product. Flavouring agents like this compound are added in very low concentrations to contribute nuanced aromatic and sensory characteristics that cannot be achieved by more common ingredients alone. Compounds in this class can add complexity to flavour profiles in products ranging from savory snacks to beverages, enhancing overall consumer appeal. The functional rationale for using 2-CYCLOHEXENONE is rooted in flavour chemistry: small cyclic ketones often have distinct olfactory qualities that can complement or balance other flavour components. In formulations where a roasted, fruity, green, or slightly ketonic note is desirable, this compound can serve as a key component. Because it is used at trace levels relative to the bulk ingredients in a formulation, its impact is primarily sensory and does not significantly contribute nutritive value or volume. Manufacturers select flavouring agents like 2-CYCLOHEXENONE based on rigorous sensory evaluation and formulation testing. These compounds are evaluated for compatibility with other ingredients, stability under processing conditions, and how they interact with the overall flavour profile of the finished product. In many cases, such flavouring agents are considered technical aids that help products meet specific consumer expectations for aroma and taste without altering other functional properties such as texture or shelf stability.

Adi Example Calculation

To illustrate how an ADI concept might be interpreted in practice, consider a hypothetical flavouring agent with an ADI value derived by a regulatory body. For example purposes only, suppose a flavouring agent had an ADI of X milligrams per kilogram of body weight per day. A 70 kilogram adult could theoretically consume X times 70 milligrams over the course of a day without exceeding the ADI. Because 2-CYCLOHEXENONE is used at very low levels in food formulations, typical daily intake from all food sources would be orders of magnitude below such a hypothetical ADI, supporting the conclusion of no safety concern at current levels of intake. Again, this illustration is hypothetical and not specific to a confirmed numeric ADI for this compound, but serves to illustrate how the concept relates to real-world consumption.

Safety And Health Research

Safety assessments for flavouring agents such as 2-CYCLOHEXENONE involve evaluating toxicological data, likely including genotoxicity, subchronic toxicity, metabolism, and potential for adverse effects at typical exposure levels. Expert committees like JECFA review such data in the context of estimated exposure from intended uses in food to determine whether there is a safety concern. For 2-CYCLOHEXENONE, the committee concluded there is no safety concern at current levels of intake when used as a flavouring agent. It is important to emphasize that such assessments consider the compound within the context of flavour use, where usage levels are extremely low relative to total food intake. This means that systemic exposure is limited in comparison to inherent chemical hazards that might be observed at high doses in laboratory settings. The safety determination reflects a balance between exposure estimates and toxicological thresholds identified in studies. Research into the health effects of specific compounds often continues beyond initial evaluations, and regulatory bodies may update assessments as new data become available. In cases where data are scarce, expert committees may rely on structural analogies and established scientific principles to inform their evaluations. For 2-CYCLOHEXENONE, the existing evaluation suggests that typical intake through flavour use does not pose a safety risk.

Regulatory Status Worldwide

2-CYCLOHEXENONE has been evaluated by expert bodies that consider flavouring agents and food chemical safety. The World Health Organization and the Food and Agriculture Organization of the United Nations maintain a database of food additives evaluated by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), and 2-CYCLOHEXENONE is listed with its functional classification as a flavouring agent under JECFA number 2052. According to the JECFA evaluation, there is no safety concern at current levels of intake when used as a flavouring agent under intended conditions of use. This reflects the expert committee's assessment based on available toxicological and exposure information. In the United States, the Flavor and Extract Manufacturers Association (FEMA) includes this compound in its flavour ingredient library with a FEMA GRAS reference number, indicating that it has been evaluated by the FEMA Expert Panel for safety when used as a flavouring. However, inclusion in industry flavour libraries does not constitute a formal approval in specific Code of Federal Regulations sections, and as such the U.S. Food and Drug Administration (FDA) does not list specific regulatory sections for this compound's use. It appears in the Substances Added to Food inventory, which reflects flavouring substances evaluated by FEMA and JECFA but does not itself confer a direct FDA regulation citation. Regulatory frameworks differ by jurisdiction, and the presence of a compound on expert evaluation lists suggests recognition of safety in context of intended use. Numeric regulatory limits, such as maximum use levels or Acceptable Daily Intake (ADI) values, may not be established in every regulatory system for flavouring agents when expert bodies have concluded that typical levels of use result in negligible risk. The evaluation by JECFA specifically concluded that there is no safety concern at current levels of intake, reflecting a risk assessment approach that integrates exposure and toxicological data.

Taste And Functional Properties

The sensory profile of 2-CYCLOHEXENONE is defined by its ketone-based aroma notes. Ketones in flavour chemistry often convey distinctive sensory impressions such as roasted, green, or slightly sweet aromatic undertones. These characteristics make such compounds useful in creating complex flavour profiles where singular sensory notes would otherwise be flat or unbalanced. Industry flavour libraries describe the organoleptic properties of such compounds with detail that helps formulators match specific sensory outcomes. In terms of functional behaviour, 2-CYCLOHEXENONE is moderately soluble in common organic solvents and its stability is influenced by processing conditions such as temperature and pH. As with many enones, it can be sensitive to prolonged heat or strong acid/base conditions, which may affect its sensory attributes or chemical integrity. It is therefore typically introduced at stages of formulation when such conditions can be controlled to preserve its aromatic contribution. The functional properties of such flavouring agents also include how they interact with other flavour components. For example, some ketonic flavour molecules can synergize with fruity esters or spicy terpenes to enrich the overall sensory experience. When used in combination with other carefully selected flavour ingredients, 2-CYCLOHEXENONE helps create a balanced and rounded aromatic profile that meets specific product criteria.

Acceptable Daily Intake Explained

An Acceptable Daily Intake (ADI) is a concept used in food safety to denote the amount of a substance that can be ingested daily over a lifetime without appreciable health risk, based on toxicological studies and exposure assessments. For many flavouring agents, ADIs may not be explicitly established if expert evaluations indicate that exposure at intended use levels is below levels of concern, as appears to be the case for 2-CYCLOHEXENONE in the JECFA evaluation. Importantly, an ADI is not a target intake level but a safety benchmark derived from scientific studies. When a compound is evaluated and found to have no safety concern at current intake levels, it suggests that typical consumption through authorised flavour use is well below thresholds that might cause adverse effects in toxicological studies. This provides a regulatory and scientific context for industry and regulators to consider when determining appropriate use levels. The ADI framework helps communicate that safety assessments consider both hazard and exposure in a rigorous manner.

Comparison With Similar Additives

When comparing 2-CYCLOHEXENONE with similar flavouring agents, several other small ketones and cyclic compounds are notable. For example, cyclohexanone derivatives and other enones may also be used as flavouring agents where they contribute distinct sensory notes. These compounds often share functional properties such as volatile aromatic profiles and similar chemical behaviour in formulation. Other flavouring agents such as simple aliphatic ketones or lactones also provide aroma contributions but differ in the specific sensory cues they add; for instance, diacetyl provides buttery notes while gamma-dodecalactone imparts creamy peach-like aromas. The choice between such compounds depends on the target flavour profile. In terms of safety evaluations, many small flavouring agents are assessed by the same expert committees and found to have no safety concern at typical intake levels, reflecting a broad regulatory approach that considers both chemical properties and estimated exposure. Comparing across these substances emphasizes the diversity of flavouring agents and the common frameworks used to assess their safety and functional utility.

Common Food Applications Narrative

Flavouring agents like 2-CYCLOHEXENONE are used across a diverse array of food and beverage products to enhance sensory appeal. In the formulation of savory snacks, beverages, confectionery items and other processed foods, small quantities of flavouring agents are incorporated to influence aroma and subtle taste perceptions. These agents are typically used at trace levels that are imperceptible in isolation, but contribute significantly when combined with other flavour compounds and food matrices. The art and science of flavour formulation involve identifying the right combination of compounds to achieve a targeted sensory outcome. Compounds such as 2-CYCLOHEXENONE are selected based on their ability to add desired aromatic nuances without overpowering other ingredients. For example, in beverages that aim for a balanced aroma profile with both fruity and green notes, a ketonic compound can help bridge flavor elements. In snacks with roasted or complex aromatic goals, such flavouring agents contribute depth that enhances consumer perception. Overall, the use of such specialised flavouring agents reflects the detailed sensory design that goes into modern food and beverage products. These compounds are tools for skilled flavourists who craft nuanced sensory experiences that align with consumer expectations and product positioning. Their use is widespread in complex formulations where multiple aromatic cues must coexist harmoniously.

Safety & Regulations

FDA

  • Notes: No specific FDA regulation section could be identified; appears evaluated in FDA inventory via FEMA and JECFA but not listed with a formal CFR approval.

EFSA

  • Notes: No explicit EFSA E-number or numeric ADI could be confirmed from authoritative sources.

JECFA

  • Notes: JECFA conclusion of no safety concern at current intake levels is provided but a numeric ADI and year of evaluation were not explicitly shown on the d entry.
  • Adi Display: No safety concern at current levels of intake when used as a flavouring agent

Sources

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