CITRAL DIETHYL ACETAL

CAS: 7492-66-2 FLAVORING AGENT OR ADJUVANT

Citral diethyl acetal is a synthetic citrus flavoring compound used to impart citrus and lemon-like sensory notes in food flavorings under regulated conditions.

What It Is

Citral diethyl acetal is a synthetic flavoring compound used in the food and flavor industry. It is identified chemically as an acetal derivative of citral with the CAS number 7492-66-2 and is known by several names that reflect its chemical structure. This ingredient is categorized as a flavoring agent or adjuvant and is primarily included in formulations to provide citrus-like sensory characteristics, often described as medium-strength citrus with green and waxy nuances in flavor profiles. Citral diethyl acetal is a liquid at ambient temperature and has specific commercial identifiers such as FEMA number 2304 and JECFA number 948, which relate to its evaluation and use in flavorings. Regulatory frameworks recognize its use in specified applications provided it is included at levels consistent with safety evaluations and relevant guidelines. Citral diethyl acetal belongs to a family of synthetic aroma chemicals that are valued for their ability to mimic natural citrus odors and tastes. Unlike simple food ingredients such as sugars or oils, it is a deliberately synthesized compound that enhances flavor complexity in a controlled manner. Its role in flavor panels typically involves enhancing fruit and citrus notes without significantly altering the overall flavor balance in a formulation. This functional identity is important for food developers who seek consistent and reproducible sensory effects from batch to batch. In practical use, citral diethyl acetal is not a primary nutrition source or a preservative; rather, it operates as a sensory modifier. It bridges the gap between pure chemical synthesis and culinary artistry, enabling manufacturers to deliver distinct citrus characteristics in a wide range of food and beverage products.

How It Is Made

The synthesis of citral diethyl acetal involves a chemical reaction between citral, a natural or synthetic aldehyde with a lemon-like aroma, and ethanol under controlled conditions. This acetalization process forms an acetal linkage, yielding a diethyl acetal compound that is generally more stable than citral itself. Acetalization reactions of this type are commonly used in organic chemistry to protect aldehyde functionalities or to create structurally related derivatives with desirable characteristics such as altered volatility, stability, or sensory profile. Through standard industrial practice, the reaction conditions—such as temperature, catalysts, and molar ratios—are optimized to yield a high-purity product. The resulting citral diethyl acetal is typically purified by distillation or other separation techniques to remove unreacted starting materials and minor byproducts. The final purified ingredient meets defined quality specifications for use in flavor applications. These specifications often include minimum purity thresholds, refractive index measurements, and other physico-chemical parameters that ensure consistency and safety in food formulations. Manufacturers also produce citral diethyl acetal in grades suited to flavor applications, ensuring that the substance is compatible with food contact and sensory requirements. This production context supports safe and effective incorporation into flavor blends, fragrances, and related formulations. Its production mirrors other flavoring intermediates in the industry, combining efficient organic synthesis with quality controls suitable for regulated food use.

Why It Is Used In Food

Citral diethyl acetal is used in food primarily for its ability to contribute citrus-like flavor notes without the instability that may accompany some naturally derived citrus compounds. In flavor formulation, ingredients like citral diethyl acetal help round out the sensory profile of products where citrus characteristics are desirable, such as in beverages, confectionary items, baked goods, and savory snacks. Its use can complement or enhance natural citrus extracts, providing a targeted sensory effect that aligns with consumer expectations. Flavoring agents like citral diethyl acetal are chosen when formulators need robust, consistent sensory impact. Natural isolates can vary with source, harvest conditions, and processing methods, whereas a synthetic derivative offers predictable performance. Citral diethyl acetal provides this predictability, which is essential in commercial food production where consistency from batch to batch is necessary. It functions by engaging olfactory and taste receptors that contribute to the perception of citrus notes, adding nuance and complexity to a food formulation. Moreover, ingredients such as citral diethyl acetal enable food manufacturers to achieve specific flavor objectives at lower usage levels than some raw citrus components. This efficiency can be advantageous in product development, particularly when balancing multi-ingredient systems. The strategic use of a synthetic citrus-flavoring agent aligns with modern flavor design practices that value sensory precision and formulation stability.

Adi Example Calculation

Because a formal numeric ADI specific to citral diethyl acetal was not established by JECFA’s evaluation, an illustrative example calculation using a hypothetical ADI cannot be provided with authoritative numerical values. Instead, the concept of this approach can be described generally: if a numeric ADI were defined, the typical process would involve multiplying the ADI value by a hypothetical body weight (e.g., a 60 kg adult) to determine a lifetime daily intake that is unlikely to pose health concerns. This calculation is intended for conceptual understanding and not as a directive for individual consumption. In regulatory practice, where an ADI is defined, such calculations help contextualize allowable daily intake relative to consumption patterns. For citral diethyl acetal, conclusions of no safety concern at typical levels of dietary intake reflect a broader safety context rather than a specific numeric threshold. Therefore, users of this information should interpret illustrative calculations as conceptual frameworks rather than specific guidance.

Safety And Health Research

Safety evaluations for citral diethyl acetal have been undertaken by authoritative bodies that assess chemical substances used as flavoring agents. JECFA’s evaluation concluded that at typical exposure levels from flavoring use there is no safety concern, reflecting consideration of available toxicological and intake data for this compound. Evaluations generally consider metabolic pathways and toxicological evidence to determine if typical use levels in food present a risk to human health. Studies on related aliphatic acetals and their metabolic fate indicate that compounds of this class are metabolized to component alcohol and aldehyde fragments that are further processed and eliminated from the body. While extensive primary toxicology data specific to citral diethyl acetal may be limited, assessments of flavoring group members with similar structure suggest efficient metabolism and elimination pathways that are consistent with safety at low use levels. Regulatory reviews incorporate data on acute toxicity, metabolic pathways, and intake estimates to inform safety conclusions. It is important to note that these safety conclusions are based on typical usage levels in foods and beverages and assume adherence to regulatory guidelines and good manufacturing practices. As with all flavoring substances, compliance with specified use conditions contributes to maintaining consumer safety in the context of intended applications.

Regulatory Status Worldwide

Citral diethyl acetal is recognized within regulatory frameworks for flavoring substances in food. In the United States, it is listed in the FDA Substances Added to Food inventory with the relevant regulation citation 21 CFR 172.515, which pertains to the use of flavoring agents and adjuvants consistent with good manufacturing practice. This listing indicates that its use is acknowledged by FDA as part of recognized flavoring practices under specified conditions. Similar listings are maintained in flavoring inventories that support regulatory oversight of flavor ingredients. Internationally, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) evaluated citral diethyl acetal (JECFA number 948) and found "no safety concern at current levels of intake when used as a flavouring agent" based on available data at the time of that evaluation. This evaluation supports its acceptance in flavor use under controlled conditions. Regulatory frameworks in regions such as the European Union manage flavoring substances under specific regulations, where inclusion on permitted lists or in flavor inventories confirms their acceptability under defined conditions. The broader regulatory landscape for flavorings incorporates assessments by scientific bodies that consider intake, usage patterns, and safety data when determining authorized uses.

Taste And Functional Properties

Citral diethyl acetal imparts a citrus-like sensory character that is generally described as green, fresh, and reminiscent of lemon peel with subtle waxy undertones. This flavor profile makes it useful where bright, citrus-enhanced notes are desired without overwhelming other components of the flavor matrix. Its sensory attributes are frequently characterized by professional flavorists and documented in flavor reference databases based on standardized sensory evaluation methods. In terms of functional properties, citral diethyl acetal is moderately volatile, meaning it contributes aroma both during consumption and upon initial olfactory perception. Its solubility profile includes miscibility in organic solvents such as alcohol but limited solubility in water. These solubility characteristics influence how it is incorporated into different product systems, such as emulsified beverages versus aqueous-flavored syrups. It also exhibits moderate stability under typical food processing conditions, though precise stability may vary depending on pH, temperature, and formulation matrices. Citral diethyl acetal’s chemical stability tends to exceed that of citral itself, which can be prone to oxidation. This stability supports its use in formulated products where shelf-life performance is an important consideration. Although it is used at relatively low concentrations, its influence on overall flavor perception can be significant, enabling precise adjustments in flavor profiles without contributing undesirable off-notes.

Acceptable Daily Intake Explained

The concept of acceptable daily intake (ADI) is used by international bodies to describe an estimate of a substance amount that can be consumed daily over a lifetime without appreciable health risk. For citral diethyl acetal, JECFA’s evaluation did not establish a numeric ADI but stated that at expected intake levels from flavoring use there is no safety concern. This type of conclusion suggests that exposures under conditions of intended use are below levels that would raise safety concerns based on available data. ADI values are typically expressed in units such as milligrams per kilogram of body weight per day and are derived from toxicological data with the application of safety factors to account for uncertainties. Where a numeric ADI is not established, regulatory bodies may conclude that the substance is acceptable for use within specified parameters without quantifying a daily intake threshold. This reflects a regulatory context in which evidence supports safe use at typical consumption levels without identifying specific risk thresholds.

Comparison With Similar Additives

Citral diethyl acetal can be compared with other citrus-related flavoring compounds such as citral itself, citral dimethyl acetal, and other citrus esters used in flavor formulation. Citral, a naturally occurring aldehyde with a strong lemon aroma, is more prone to oxidation and may require stabilization in certain applications, whereas citral diethyl acetal offers improved stability due to its acetal structure, which resists some chemical degradation pathways. Citral dimethyl acetal is another acetal derivative with similar functional applications but differs in volatility and sensory nuances, providing flavorists with options that vary in sensory intensity and stability. Other citrus esters such as ethyl butyrate or lemon oil constituents provide different sensory signatures and metabolic profiles. These compounds are selected based on the specific flavor character desired: some offer bright fruity impressions, while others contribute depth or complexity. Compared to simple esters, acetals like citral diethyl acetal may provide more nuanced citrus notes with reduced volatility, making them useful in products where a sustained sensory presence is preferred. This functional comparison highlights how structural variations among flavoring agents influence their sensory contributions and formulation utility.

Common Food Applications Narrative

Citral diethyl acetal is incorporated into a range of food and beverage flavors where citrus notes are desirable. In beverage applications, it can help impart fresh lemon or lime impressions, contributing to the character of soft drinks, flavored waters, and ready-to-drink teas. Its use in confectionary products, such as candies or chewing gums, helps emphasize bright citrus characteristics that appeal to consumers seeking refreshing flavor experiences. In baked goods and frostings, citral diethyl acetal can provide subtle citrus enhancements that elevate fruit-forward profiles without dominating sweetness or other flavor elements. Its application extends to savory products where a hint of citrus brightness can balance richness, such as in certain sauces, dressings, or marinades. The compound’s contribution to flavor extends beyond sweet products, making it a versatile tool for flavorists. When formulating citrus-flavored products, manufacturers often blend citral diethyl acetal with other flavor constituents to replicate complex natural citrus profiles. This blending approach enables product developers to achieve a rounded sensory experience that consumers associate with natural fruit flavors. The controlled use of this compound in food flavorings reflects industry best practices for ensuring consistent flavor delivery in mass-produced products.

Safety & Regulations

FDA

  • Notes: Listed in FDA Substances Added to Food inventory consistent with flavoring use; formal approved boolean not specifically stated in available regulatory listing
  • Regulation: 21 CFR 172.515

EFSA

  • Notes: No specific EFSA numeric ADI found in available sources

JECFA

  • Year: 2001
  • Adi Display: No safety concern at current levels of intake when used as a flavouring agent

Sources

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