CITRAL DIMETHYL ACETAL

CAS: 7549-37-3 FLAVORING AGENT OR ADJUVANT

Citral dimethyl acetal is a synthetic flavoring agent used to impart citrus-like aroma properties in food and beverage applications. It is listed among synthetic flavoring substances permitted under U.S. food additive regulations and evaluated internationally for safety when used at levels typical of flavoring uses.

What It Is

Citral dimethyl acetal is a synthetic flavoring agent or adjuvant with a citrus-like aromatic profile used to enhance or modify the taste and aroma of food products. Identified by the CAS number 7549-37-3, this compound is chemically a dimethyl acetal derivative of citral, a monoterpenoid aldehyde. It belongs to the class of organic flavoring substances that exhibit fruity, lemon-citrus odor characteristics, making it useful in multiple flavoring applications. The ingredient is included in regulatory lists of synthetic flavoring substances authorized for use under specific regulatory conditions. Structurally, citral dimethyl acetal is defined by its characteristic dimethyl acetal functional group attached to a terpene backbone, which differentiates it from its precursor citral. This structural modification often imparts greater stability and persistence in aromatic profiles compared with the parent aldehyde. The compound’s sensory profile is generally described in technical flavor literature as fresh, citrusy, with lemon and green notes, which supports its selection by flavor chemists to achieve desired organoleptic profiles. Flavor chemists and food technologists use citral dimethyl acetal as part of complex flavor blends in food formulations where citrus notes are desirable without excessive acidity or aldehydic sharpness. It is often combined with other terpenoid flavoring substances to balance the overall sensory experience. The use of citral dimethyl acetal has been evaluated in the context of food safety assessments by international bodies such as the Joint FAO/WHO Expert Committee on Food Additives, which concluded that at typical use levels no safety concern has been identified.

How It Is Made

The production of citral dimethyl acetal involves the chemical conversion of citral, a naturally derived aldehyde commonly found in citrus essential oils, into its corresponding dimethyl acetal derivative. In general terms, this process is an acetalization reaction, where citral reacts with methanol under acidic conditions to form the stable acetal. The reaction mechanism involves the nucleophilic addition of methanol to the electrophilic carbonyl carbon of citral, followed by dehydration to yield the dimethyl acetal structure. Industrial-scale processes for flavor chemical production follow established practices that emphasize controlled reaction conditions, such as optimized temperature, acid catalyst concentration, and removal of byproduct water to drive the equilibrium toward acetal formation. Purification steps like distillation or fractional separation are used to ensure product consistency and to remove unreacted precursors or impurities. Manufacturers producing food-grade citral dimethyl acetal must adhere to quality standards that cover identity, purity, residual solvent limits, and other characteristics relevant to flavor use. Specifications often include criteria for organoleptic properties (odor and taste), appearance (colorless to pale yellow liquid), and chemical composition. These standards, while compound-specific, align with general flavor ingredient quality expectations used by regulatory and industry bodies. As with many flavoring ingredients, rigorous quality control supports consistent sensory performance and regulatory compliance in finished food formulations.

Why It Is Used In Food

Citral dimethyl acetal is used in food primarily to impart or enhance citrus-like aroma and flavor notes without the potent aldehydic sharpness associated with free citral. The acetal derivative often provides a softer, more persistent citrus character, making it valuable in products where delicate fruitiness is desired. Its use is especially relevant in formulations where typical citrus flavors might be suppressed by processing conditions or where a stable citrus note is preferred. Food technologists select this compound because of its functional contribution to flavor complexity and balance. The citrus profile can complement other fruit or spice notes, improving overall sensory appeal. Additionally, compared with some highly volatile aroma compounds, the acetal moiety may confer greater stability, meaning the citrus effect persists longer through processing and storage. In practice, citral dimethyl acetal is used at low concentrations, often as part of multi-component flavor blends, to achieve nuanced flavor profiles. It may be chosen over other citrus flavoring agents where specific sensory attributes—such as fresh green undertones combined with lemon notes—are desired. Its inclusion is guided by formulation expertise and sensory testing to match target product profiles.

Adi Example Calculation

Because citral dimethyl acetal is not associated with an explicitly numeric ADI in JECFA evaluations, an illustrative calculation framework can demonstrate how safety guidance is interpreted rather than applying a specific numeric value. For example, if a hypothetical ingredient had an ADI of X mg per kg body weight, intake estimations for a 60 kg individual consuming products containing the flavoring at typical concentrations would involve multiplying the estimated daily consumption of foods containing the additive by that concentration and dividing by body weight. In the case of citral dimethyl acetal, regulatory statements of no safety concern imply that the estimated daily intake from typical food use scenarios remains well below any level associated with toxicological thresholds.

Safety And Health Research

Regulatory and expert committee evaluations of citral dimethyl acetal focus primarily on its safety profile associated with typical food use levels rather than high-dose toxicological endpoints. The JECFA evaluation concluded that when used as a flavoring agent in food, there is no safety concern at typical levels of intake. This finding is based on comprehensive review of available data on structure, use levels in foods, metabolism, and toxicological information supporting low exposure and low inherent hazard. (世界卫生组织应用程序) The U.S. FDA’s inclusion of citral dimethyl acetal in the list of permitted synthetic flavoring substances underscores acceptance based on historical safety experience and regulatory review. The conditions specified in the regulation emphasize minimal necessary use and adherence to good manufacturing practices, aligning with general safety management principles applied to flavoring agents. (电子联邦法规系统) Toxicological studies typically consider endpoints such as general toxicity, metabolism, and potential for irritation or sensitization at exposure doses far exceeding typical dietary intake. For use as a food flavoring ingredient, such risk assessments contextualize potential hazard against actual exposure from food consumption patterns, which remain low relative to doses associated with adverse effects in experimental settings. The safety evaluation reflects a weight-of-evidence approach consistent with international regulatory science practices.

Regulatory Status Worldwide

In the United States, citral dimethyl acetal is included in the list of synthetic flavoring substances and adjuvants authorized for use under Section 172.515 of Title 21 of the Code of Federal Regulations, which covers synthetic flavoring agents that may be safely used in food when applied in accordance with good manufacturing practices. The listing of individual substances in this section serves as regulatory authorization for their use in food formulations. The specific reference in the regulatory text confirms the ingredient’s inclusion under the general category of synthetic flavoring substances. The U.S. Food and Drug Administration’s regulation emphasizes minimal effective use and adherence to good manufacturing practice principles. (电子联邦法规系统) Internationally, citral dimethyl acetal has been evaluated by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), which assigned it JECFA number 944 and classified it as a flavouring agent with no safety concern at current levels of intake for typical flavoring use. The JECFA evaluation, conducted in 2001, supports its safety when used at levels typical for flavor applications. This assessment reflects international scientific consensus regarding low exposure levels associated with flavor use and the lack of identified toxicological risk in that context. (世界卫生组织应用程序) European regulatory bodies consider similar flavoring substances with reference to both flavor inventories and specific evaluations; however, a distinct E-number designation for citral dimethyl acetal is not explicitly established in the EFSA database. Ongoing regulatory updates and updates to flavoring inventories may provide further clarification for specific jurisdictions.

Taste And Functional Properties

Citral dimethyl acetal is characterized by a prominent citrus-like aroma with lemon and slight green notes that contribute to its use as a flavoring agent. The sensory impression is typically perceived as cleaner and less sharp than free citral, which makes this compound suitable for applications where a subtle citrus nuance is needed without overpowering other flavor components. From a functional perspective, citral dimethyl acetal exhibits behavior typical of small, volatile organic molecules used in flavoring. Its solubility in lipophilic matrices and organic solvents supports its use in a range of food systems, particularly those with fat or oil components where aroma retention may be advantageous. Its water solubility is limited, which aligns with its behavior in emulsion and beverage systems where partitioning behavior must be taken into account by formulators. In formulation practice, the stability of the acetal group under typical food processing conditions—such as moderate heat or neutral pH—helps preserve the desired aroma during mixing, cooking, or shelf storage. However, like many aroma compounds, extremely high heat or strongly acidic conditions may influence its integrity, and such factors are considered when selecting flavoring ingredients. Overall, its waxy citrus profile and functional properties make it versatile across a range of products where citrus-like notes are sought.

Acceptable Daily Intake Explained

An acceptable daily intake (ADI) is a concept used by regulatory bodies to describe the amount of a substance that can be consumed daily over a lifetime without appreciable health risk, based on available toxicological data. For many flavoring agents, including citral dimethyl acetal, specific numeric ADIs are not always established; instead, because of low typical intake and supportive safety data, regulators like JECFA conclude that there is no safety concern at current levels of intake. In practice, this means that typical dietary exposure from flavor uses falls well below levels that would raise concern based on available data and expert assessment. (世界卫生组织应用程序) The concept of “no safety concern at current levels of intake” effectively serves a similar purpose as an ADI by indicating that ordinary use patterns do not approach thresholds associated with toxicological effects. Regulatory evaluations take into account both the inherent properties of the compound and estimates of exposure based on reported use levels in foods.

Comparison With Similar Additives

Citral dimethyl acetal can be compared with other citrus-related flavoring agents such as citral itself, citronellal, and limonene based on sensory and functional attributes. Citral provides a sharp, lemon-like aldehydic note often used in citrus flavor profiles, but its reactivity and potent aroma can be a challenge in formulations; by contrast, the dimethyl acetal derivative exhibits a softer, longer-lasting citrus nuance that is easier to integrate into balanced flavor blends. Citronellal offers floral citrus notes with a slightly sweeter character, while limonene contributes a bright orange-citrus profile. Each compound’s specific sensory qualities determine their selection and combination in complex flavor systems. The differences in chemical structure also influence stability and volatility, impacting how formulators use these agents to achieve targeted sensory outcomes.

Common Food Applications Narrative

Citral dimethyl acetal finds its role in a variety of food products where citrus aroma notes complement other flavor elements. In beverage programs, for example, it can be part of flavor blends designed to evoke lemon, lime, or other citrus sensations without the acidity or tartness associated with direct citrus extracts. Its nuanced profile supports layered flavor experiences in both still and carbonated drinks. In confectionery and baked goods, citral dimethyl acetal contributes subtle citrus top notes that help balance sweetness and provide complexity in products such as fruit-flavored candies, frostings, or cookies. Similarly, its use in dairy-based products like frozen desserts or flavored yogurts supports the creation of refreshing flavor attributes that appeal to consumer expectations for mild fruitiness. Savory applications can also benefit from its inclusion, particularly in sauces or dressings aiming to achieve a bright, fresh character when citrus undertones are appropriate. The compound’s aroma profile can interact with other herbs and spices to create memorable sensory profiles without dominating the overall taste. Across these applications, the use of citral dimethyl acetal is typically at low levels consistent with good flavor practice. Its inclusion is guided by sensory evaluation and targeted product profiles, ensuring that the citrus-like character enhances without overwhelming other notes. This versatility underscores why flavorists and product developers select compounds like citral dimethyl acetal as part of comprehensive flavor strategies.

Safety & Regulations

FDA

  • Approved: True
  • Regulation: 21 CFR 172.515

EFSA

  • Notes: No specific EFSA numeric ADI found

JECFA

  • Year: 2001
  • Adi Display: No safety concern at current levels of intake

Sources

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