DILAURYL THIODIPROPIONATE

CAS: 123-28-4

Dilauryl thiodipropionate is a sulfur ester antioxidant used in food fats/oils under controlled limits and as an antioxidant in various materials.

What It Is

Dilauryl thiodipropionate is a synthetic antioxidant compound characterized by a sulfur-containing ester structure formed from thiodipropionic acid and lauryl alcohol. It has the Chemical Abstracts Service (CAS) registry number 123-28-4 and is recognized with the International Numbering System (INS) number 389 for food additive classification. In chemical terms, it belongs to the class of secondary antioxidants, meaning it can interrupt oxidative chain reactions in lipids and other susceptible molecules. It is typically encountered as white crystalline flakes or powder with a mild sweetish ester-like odor. In the context of food uses, dilauryl thiodipropionate functions primarily to retard the oxidative rancidity of fats and oils when included within prescribed limits and is often accompanied with other antioxidant systems to enhance shelf-life effects. Although its technical function is not directly related to flavor, color, or nutrient content, these oxidation-retarding properties can indirectly support product quality by preserving sensory and nutritional characteristics of food fats. INS 389 additives are recognized in international food additive standards and databases, which classify antioxidants by mechanism and functional role in food systems, though not all jurisdictions treat INS numbers uniformly in regulatory text. The sulfur moiety in dilauryl thiodipropionate’s structure confers enhanced reactivity toward peroxyl radicals compared to simple hydrocarbon antioxidants, which underlies its utility in fat stabilization applications.

How It Is Made

The manufacturing of dilauryl thiodipropionate involves an esterification reaction between thiodipropionic acid and lauryl alcohol under controlled conditions with an acid catalyst. This chemical process forms ester linkages that connect the long-chain dodecyl (lauryl) groups to the thiodipropionic acid backbone, generating a symmetrical ester that is hydrophobic and soluble in organic lipid phases. Industrial synthesis typically proceeds in stages where the acid and alcohol are reacted in the presence of dehydration to drive the equilibrium toward ester formation, followed by purification steps to remove unreacted starting materials and byproducts. The final product is often crystallized and milled to achieve a consistent particle size for formulation use. Quality specifications for dilauryl thiodipropionate intended for food contact applications generally require a high degree of purity, often above 99%, to meet safety and performance criteria. International monographs detail identity tests and limits for impurities such as residual acidity or heavy metals, which are important for ensuring that the additive meets safety and functionality standards. For example, FAO/WHO Codex monographs provide parameters for identification and purity criteria that are used as references in global specifications. Adherence to such specifications supports consistency and quality in the manufactured material. Manufacturers may produce dilauryl thiodipropionate in batch reactors followed by distillation or crystallization steps to meet these specifications. The process design considers solvent selection, reaction temperature, and catalyst loadings to maximize yield and limit degradation or side reactions. Handling and storage of the intermediate and final product are managed under conditions that minimize exposure to moisture and contaminants, given the additive’s reactivity and intended use in food-related systems.

Why It Is Used In Food

Dilauryl thiodipropionate is used in foods primarily for its antioxidant function. Oxidation of fats and oils is a leading cause of quality deterioration in many food products, resulting in off-odors, off-flavors, and degradation of fatty acid nutrients. Antioxidants like dilauryl thiodipropionate slow oxidative reactions by neutralizing free radicals and terminating chain reactions that lead to lipid peroxidation. This technical function can extend the shelf life of foods that contain significant amounts of unsaturated fats, particularly vegetable oils or fat-containing processed foods. In food systems, dilauryl thiodipropionate typically works adjunctively with other antioxidants and is formulated such that the total antioxidant content remains within regulatory limits. For example, in fats and oils intended for human consumption, the total antioxidant content is controlled to a small percentage of the fat weight, and practices of good manufacturing dictate appropriate usage levels to achieve oxidative stability without exceeding safety thresholds. By inhibiting oxidation, this additive can help maintain product quality during storage and distribution, thereby reducing waste and improving consumer satisfaction with the product’s sensory attributes. The decision to include dilauryl thiodipropionate in a food formulation is usually driven by the stability requirements of the specific product. Foods prone to oxidation, such as salad dressings, margarine, or powdered fats, benefit most from secondary antioxidant systems. In addition, the antioxidant may be included to support packaging technologies that reduce oxygen ingress or work in tandem with primary antioxidants that act earlier in the oxidation process. Its use reflects a broader strategy of quality preservation in modern food production, supporting shelf life and consistency across batches.

Adi Example Calculation

An illustrative example of understanding an ADI for an antioxidant like dilauryl thiodipropionate involves imagining a hypothetical ADI expressed in milligrams per kilogram of body weight. For example, if an expert committee were to establish an ADI of a certain number of milligrams per kilogram of body weight, a person weighing 70 kilograms would have an allowable daily intake calculated by multiplying the ADI value by body weight. If that numeric ADI value were explicitly provided by a regulatory evaluation, the calculation would reflect how much of the additive could be consumed daily without expected risk when accumulated from all food sources. However, because the specific numeric ADI for dilauryl thiodipropionate has been historically discussed in expert evaluations rather than universally codified, this illustrative calculation emphasizes the conceptual use of ADIs rather than prescribing a definitive intake limit.

Safety And Health Research

The safety assessment of dilauryl thiodipropionate centers on its chemical behavior, metabolism, and toxicity profile to support its use as an antioxidant in food-related applications. Antioxidant food additives are evaluated for potential effects related to general toxicity, metabolic pathways, and any specific organ or systemic impacts. Evaluations typically involve reviewing toxicological data from animal studies to identify potential hazards and establish safety thresholds. International expert evaluations, such as those by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), provide comprehensive reviews of such data. Historical JECFA evaluations of dilauryl thiodipropionate have included considerations of acute and chronic toxicity studies and assessments of conditional acceptable daily intakes. These evaluations inform the inclusion of the compound in international food additive standards and guide regulatory decisions in different regions. Safety research also encompasses assessments of the additive’s behavior in food matrices and potential migration from food contact materials when used in packaging. Regulatory frameworks that list dilauryl thiodipropionate under indirect food additive provisions include considerations for migration limits and good manufacturing practices to ensure that consumer exposure remains within safe and controlled bounds. By focusing on hazard identification and exposure assessments, food safety authorities aim to ensure that the use of antioxidants like dilauryl thiodipropionate does not pose undue risk when used in accordance with regulatory limits and conditions.

Regulatory Status Worldwide

Dilauryl thiodipropionate is recognized in regulatory systems around the world with respect to food contact and antioxidant functions, but its permitted uses and conditions vary by jurisdiction. In the United States, this substance appears in the Code of Federal Regulations (21 CFR) under sections related to indirect food additives and food contact substances. Listings under 21 CFR parts such as 175.300 (resinous and polymeric coatings), 177.1010 (lubricants with incidental food contact), 181.24 (prior-sanctioned substances), and 182.3280 (generally recognized as safe substances) indicate that dilauryl thiodipropionate can be employed under specified conditions for food contact materials or as GRAS for direct food use when the total antioxidant content is appropriately limited. These references provide the regulatory framework for compliance in packaging and processing applications in the U.S. market. Internationally, dilauryl thiodipropionate is assigned INS number 389 in the Codex General Standard for Food Additives (GSFA), where it is categorized within the class of antioxidants. The Codex GSFA database lists additives by INS number and functional class, serving as a reference for member countries developing national regulations. It is important to note that specific food category provisions and maximum use levels for INS 389 may not be universally adopted in all countries and can differ between jurisdictions, requiring manufacturers to consult local regulations. Furthermore, evaluations by international expert bodies, such as the Joint FAO/WHO Expert Committee on Food Additives (JECFA), provide scientific assessments that inform national and regional regulatory decisions. JECFA has historically reviewed dilauryl thiodipropionate and provided safety evaluations that are referenced in global food additive standards. While regulatory statuses differ globally, the presence of this additive in both U.S. CFR listings and international GSFA reflects its recognized technical use when applied within defined safety frameworks.

Taste And Functional Properties

By itself, dilauryl thiodipropionate does not impart a predominant taste or flavor characteristic when used within regulatory limits in food fats and oils. Its presence at the low concentrations typical for antioxidant function is generally below sensory thresholds for taste and odor, meaning it does not significantly alter the taste profile of the food. The primary functional property of this compound arises from its chemical ability to interact with lipid radicals, thereby interrupting oxidative reactions that can produce rancid flavors and odors. Sensory neutrality at functional use levels is an important consideration for food technologists, as additives should not introduce undesirable sensory notes. Functionally, dilauryl thiodipropionate exhibits solubility in organic lipid phases and limited solubility in aqueous environments. This characteristic aligns with its role in stabilizing fats and oils, as lipid solubility enhances its distribution throughout the fat phase where oxidative reactions occur. The functional stability of the antioxidant can vary with temperature and processing conditions; it must remain active during typical food processing steps such as heating or emulsification. A food technologist must consider both the processing environment and the food matrix to select appropriate antioxidant systems. Although antioxidant activity does not directly contribute to macronutrient nutrition, it serves a stabilizing function that can indirectly preserve the sensory and nutritional qualities of foods. Oxidative degradation can reduce essential fatty acid integrity and produce off-flavor compounds. By mitigating these reactions, dilauryl thiodipropionate supports product quality during storage, especially in products with unsaturated fats that are inherently more prone to oxidation.

Acceptable Daily Intake Explained

An acceptable daily intake (ADI) is a scientific estimate of the amount of a substance that can be consumed daily over a lifetime without appreciable health risk, expressed on a body weight basis. It is derived by expert committees based on toxicological studies and incorporates safety factors to account for uncertainties in data and differences between species. For food additives such as dilauryl thiodipropionate, ADIs are established by international bodies like the Joint FAO/WHO Expert Committee on Food Additives (JECFA) after reviewing relevant toxicity data. Although numerical ADIs have been historically discussed for dilauryl thiodipropionate, current regulatory standards rely on collective assessments and specific conditions of use rather than standalone numeric daily intake values. When an ADI is defined, it serves as a reference for regulatory authorities to set permitted use levels and to ensure that consumer exposure through diet remains within safe bounds. Food manufacturers use these guidelines to formulate products in a way that keeps potential intake below the ADI, even for high consumers of foods containing the additive.

Comparison With Similar Additives

Dilauryl thiodipropionate can be compared with other antioxidant food additives that serve similar functions in stabilizing fats and oils. For instance, butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) are widely used synthetic antioxidants that interrupt lipid oxidation chain reactions, much like dilauryl thiodipropionate. However, BHT and BHA are simpler phenolic compounds with different solubility and reactivity profiles, which can influence their distribution and effectiveness in various food matrices. The choice among these antioxidants often depends on the specific food product’s composition, processing conditions, and regulatory acceptance. Another related compound category includes propyl gallate, which is also used to delay oxidative rancidity in fats and oils. Propyl gallate differs chemically from dilauryl thiodipropionate in structure and antioxidant mechanism but shares the functional goal of extending shelf life. When formulating antioxidant systems, manufacturers may combine primary antioxidants like propyl gallate with secondary antioxidants such as dilauryl thiodipropionate to achieve a broader spectrum of protection against oxidation. These combinations can exploit synergistic effects that enhance overall stability. Comparing these compounds highlights that while all serve antioxidant roles, their chemical properties and regulatory contexts shape how and where they are used in food products.

Common Food Applications Narrative

Dilauryl thiodipropionate finds use in a range of food systems where oxidation of lipids is a concern. In edible oils and fats, this antioxidant helps maintain freshness by slowing the breakdown of unsaturated fatty acids that can lead to rancidity. For products that contain vegetable oils or blended fats, including spreads, dressings, and emulsified sauces, the stability afforded by antioxidants like dilauryl thiodipropionate can be important for preserving sensory quality over shelf life. Its use in such products aligns with a broader practice of incorporating antioxidant systems to support consistency and quality in commercial food offerings. In addition to bulk fats, dilauryl thiodipropionate may be included in powdered fat-containing ingredients and dry mixes that incorporate fat as part of the formulation. In these matrices, oxidative stability can impact not only flavor but also the performance of the ingredient during rehydration or cooking. For example, powdered sauces or meal replacements with significant fat content may require antioxidant protection to prevent off-odor development in storage. Food packaging materials that contact fatty foods may also utilize antioxidants in polymeric structures to limit oxidation of both the packaging and the packaged food. While this falls under food contact materials rather than direct food ingredients, the overarching goal remains the same: minimizing oxidative changes that can affect product quality. For manufacturers and formulators, identifying appropriate antioxidant strategies is a key component of product design, especially for items with extended shelf life or distribution in variable storage conditions. The inclusion of dilauryl thiodipropionate must always adhere to regulatory provisions that define allowable conditions of use and maximum limits to ensure consumer safety and compliance with applicable standards.

Safety & Regulations

FDA

  • Approved: True
  • Regulation: 21 CFR 175.300; 21 CFR 177.1010; 21 CFR 181.24; 21 CFR 182.3280

EFSA

  • Notes: EFSA specific numeric ADI not identified in d sources
  • E Number: 389

JECFA

  • Notes: Numeric ADI range historically discussed in JECFA reports but not confirmed on current deep link
  • Ins Number: 389

Sources

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