What is Citronellyl Trans-2-methyl-2-butenoate?
Citronellyl Trans-2-methyl-2-butenoate (CAS Number: 24717-85-9) is a chemical compound classified as an organic ester. It is formed through the esterification of citronellol, an alcohol naturally found in the essential oils of plants like roses and geraniums, and trans-2-methyl-2-butenoic acid, also known as tiglic acid. While its constituent components can be found in nature, the compound used in food applications is typically manufactured synthetically to ensure purity, consistency, and controlled production. Its primary role in food is as a flavoring agent or adjuvant, meaning it is added to food products to impart specific aromatic notes or to enhance existing flavors without being consumed for its nutritional value.
Common Uses
Citronellyl Trans-2-methyl-2-butenoate is exclusively employed in the food and beverage industry as a flavoring agent. Its specific chemical structure allows it to contribute distinct sensory attributes, often described as fruity, floral, or green notes, depending on the concentration and other ingredients present. As a high-impact flavor compound, it is typically used at very low concentrations. It finds application across a wide array of food categories, including but not limited to: soft drinks and alcoholic beverages, confectionery items like candies and chewing gums, baked goods, dairy products such as yogurts and ice creams, and various desserts. When functioning as an 'adjuvant,' it serves to modify, round out, or intensify other flavors present in a food product, contributing to a more complex and desirable taste profile.
Safety Assessment
The safety of Citronellyl Trans-2-methyl-2-butenoate for use as a flavoring agent has been rigorously evaluated by authoritative scientific bodies. The Flavor and Extract Manufacturers Association (FEMA) Expert Panel has affirmed this substance as Generally Recognized As Safe (GRAS) for its intended use as a flavoring agent (FEMA GRAS No. 4087). FEMA's GRAS determination involves a comprehensive review of all available scientific and toxicological data, including the substance's chemical properties, metabolic fate in the body, acute and subchronic toxicity studies, and genotoxicity assays. The panel also considers estimated dietary exposure levels, which for flavoring agents are typically very low. Esters like Citronellyl Trans-2-methyl-2-butenoate are generally metabolized in the digestive system, hydrolyzing into their parent alcohol (citronellol) and acid (trans-2-methyl-2-butenoic acid), which are then further metabolized and excreted by the body. Both citronellol and tiglic acid have undergone individual safety evaluations and are also widely accepted as safe for use in food at flavoring levels. Furthermore, regulatory records from the U.S. Food and Drug Administration (FDA) indicate 0 reported adverse events and 0 recalls associated with Citronellyl Trans-2-methyl-2-butenoate, suggesting a lack of significant public safety concerns during its commercial use. The European Food Safety Authority (EFSA) has also evaluated this compound, concluding 'no safety concern at current levels of use' within the European Union.
Regulatory Status
**United States:**
In the United States, Citronellyl Trans-2-methyl-2-butenoate is not explicitly listed as FDA GRAS. However, its use as a flavoring substance is permitted based on its affirmation as Generally Recognized As Safe (GRAS) by the Flavor and Extract Manufacturers Association (FEMA GRAS No. 4087). The FDA generally acknowledges and accepts FEMA's GRAS determinations, allowing the ingredient to be used in food products under the conditions of good manufacturing practice and at levels not exceeding those required to achieve its intended flavoring effect. Manufacturers are responsible for ensuring their use of the substance aligns with the FEMA GRAS determination.
**European Union:**
Within the European Union, Citronellyl Trans-2-methyl-2-butenoate is authorized for use as a flavoring substance in accordance with Regulation (EC) No 1334/2008 on flavorings and certain food ingredients with flavoring properties. The European Food Safety Authority (EFSA) conducted a safety assessment of this flavoring substance as part of Flavoring Group Evaluation 10, Revision 4 (FGE.10 Rev 4, published in 2014). Specifically, it falls under subgroup 4.1, which covers esters of primary alcohols and branched-chain carboxylic acids. EFSA's scientific opinion concluded that there is "no safety concern for the use of citronellyl trans-2-methyl-2-butenoate (FL No 09.288) at the current levels of use as a flavoring substance."
**International:**
Globally, the principles for evaluating flavoring substances are often harmonized or influenced by bodies like the Joint FAO/WHO Expert Committee on Food Additives (JECFA). While JECFA may not have a specific evaluation for this exact ester, the methodologies and robust data review processes employed by FEMA and EFSA align with international standards for assessing the safety of food ingredients.
Key Studies
The safety conclusions regarding Citronellyl Trans-2-methyl-2-butenoate are primarily derived from comprehensive evaluations conducted by expert panels such as those at FEMA and EFSA. These evaluations synthesize data from various types of studies rather than relying on a single 'key' study for public dissemination. The scientific dossier typically reviewed includes:
* **Toxicological Profile:** This encompasses acute toxicity studies (single, high-dose effects), subchronic toxicity studies (effects of repeated exposure over a moderate period, e.g., 90 days), and genotoxicity studies (assessment of potential to cause DNA damage or mutations). For esters, these studies aim to confirm that the substance does not exhibit harmful effects at typical exposure levels.
* **Metabolic Fate:** Studies or established chemical principles demonstrating how Citronellyl Trans-2-methyl-2-butenoate is absorbed, distributed, metabolized, and excreted in the body. It is generally understood that esters are hydrolyzed into their constituent alcohol and acid, which are then processed by normal metabolic pathways.
* **Exposure Assessment:** Detailed estimations of dietary intake based on reported usage levels in various food categories. This ensures that the estimated exposure remains well within safe limits established by toxicological data.
For FEMA's GRAS determination (FEMA GRAS No. 4087), the expert panel scrutinizes all available toxicological and exposure data to ensure that there is a reasonable certainty of no harm under the conditions of its intended use. Similarly, EFSA's Scientific Opinion (FGE.10 Rev 4) for the group including this compound carefully considers data on chemical structure, purity, metabolism, and existing toxicity data on the substance itself or closely related compounds, leading to their conclusion of no safety concern at current levels of use. These panel conclusions represent the aggregated scientific understanding rather than a single 'key' published paper.