STEARYL CITRATE

CAS: 1337-33-3 ANTIOXIDANT, EMULSIFIER OR EMULSIFIER SALT, SEQUESTRANT, SURFACE-ACTIVE AGENT

Stearyl citrate is a synthetic citrate ester used in food processing for its antioxidant, emulsifying, sequestrant and surfactant functions. It is prepared by esterifying citric acid with stearyl alcohol and has been affirmed as generally recognized as safe under specified conditions of use.

What It Is

Stearyl citrate is a food additive belonging to the class of citrate esters that serve multiple technical functions in food formulation. It is chemically described as a mixture of mono-, di- and tristearyl esters of citric acid and is produced by esterifying citric acid with stearyl alcohol, which imparts both hydrophilic and lipophilic properties to the molecule. The CAS Registry Number for stearyl citrate is 1337-33-3. In food applications, it functions primarily as an antioxidant, emulsifier or emulsifier salt, sequestrant and surface-active agent, helping to stabilize oil-water mixtures, chelate metal ions that catalyze oxidation, and improve overall product consistency. Stearyl citrate’s classification under food additive nomenclature reflects its multi-faceted technological roles. As an antioxidant, it helps inhibit the oxidative deterioration of fats and oils by binding metal ions and disrupting oxidative pathways. As an emulsifier and surface-active agent, it facilitates the dispersion of fat and oil droplets in aqueous phases, thereby maintaining homogeneous textures in complex food systems. Its sequestrant function relates to its ability to bind metal ions, which can affect color, flavor stability and oxidative degradation. Together these functions make stearyl citrate a useful ingredient in a range of food products where stable emulsions and oxidatively stable lipid phases are important.

How It Is Made

Stearyl citrate is synthesized via esterification, a chemical process in which the carboxylic acid groups of citric acid react with the hydroxyl group of stearyl alcohol under controlled conditions to form ester linkages. This reaction results in a mixture of stearyl citrate esters where one, two or all three carboxylic acid groups of citric acid are esterified with stearyl alcohol. The commercial preparation is designed to meet purity specifications suitable for food use, ensuring that the resulting additive is free of undesirable contaminants and by-products. High-level manufacturing practices for stearyl citrate focus on optimizing reaction conditions, such as temperature and catalysts, to achieve a consistent degree of esterification. The process typically involves removing water formed during the reaction to drive equilibrium toward ester formation. After synthesis, the product may undergo purification steps, such as washing, filtration or distillation, to remove unreacted starting materials and low-molecular-weight impurities. Food-grade stearyl citrate must conform to defined quality standards that consider factors such as acid value, ester content and absence of harmful impurities to ensure safe application in food processing.

Why It Is Used In Food

Stearyl citrate is employed in food manufacturing primarily because it addresses challenges associated with lipid-containing systems and complex product formulations. Foods that contain fats and oils, such as margarines, dairy analogs and salad dressings, can undergo oxidative degradation when exposed to oxygen, light or trace metal ions, which can cause rancidity and off-flavors. The antioxidant function of stearyl citrate helps chelate metal ions and slow down these oxidation processes, prolonging shelf life and preserving sensory quality. Beyond oxidation control, stearyl citrate functions as an emulsifier and surface-active agent, which is particularly valuable in food systems where water and oil phases must remain uniformly distributed. By lowering interfacial tension between these phases, it helps maintain stable emulsions that resist separation, leading to consistent texture and mouthfeel in formulated foods. Its sequestrant activity further enhances product stability by binding trace metals that may catalyze undesirable reactions. These technological roles make stearyl citrate a versatile additive for products such as beverages, spreads, baked goods, and sauces where product quality and stability are critical.

Adi Example Calculation

To illustrate how an ADI might be interpreted conceptually, consider a hypothetical ADI value expressed on a body weight basis, such as milligrams per kilogram of body weight per day. For instance, if an expert committee established an ADI of up to 50 mg per kilogram body weight per day for a given additive, a person weighing 70 kilograms could theoretically consume up to 3,500 mg per day without exceeding that safety threshold. This does not imply that individuals should aim to consume additive at that level; rather, it demonstrates how regulatory safety margins are framed relative to body size and lifetime exposure. In real-world dietary contexts, typical exposures to additives like stearyl citrate are well below such safety thresholds when used in foods at levels consistent with good manufacturing practice. The goal of such calculations is to provide a framework for understanding where safety assessments draw the line between typical use and theoretical limits, not to prescribe consumption targets for any individual.

Safety And Health Research

Safety evaluations for food additives like stearyl citrate consider a range of toxicological data to assess potential risks associated with dietary exposure. In historical JECFA evaluations, studies in laboratory animals examined effects such as digestibility and potential impacts at high dietary levels. These assessments inform Acceptable Daily Intake (ADI) values and safety margins used by regulators. For example, findings from early studies indicate that very high intake levels may affect fat digestibility in animal models, a parameter evaluated in the context of overall nutritional impact and systemic exposure. Such data contribute to establishing regulatory safety references that are incorporated into additive evaluations by expert committees. Safety research for stearyl citrate continues to be contextualized within broader assessments of citrate esters and structurally related compounds, considering their metabolic pathways and breakdown products. Metabolic studies suggest that ester hydrolysis leads to components such as citric acid and stearyl alcohol, which are metabolized through known physiological pathways. As with all food additives, ongoing monitoring and evaluation by regulatory bodies help ensure that new evidence can inform future safety determinations. Because stearyl citrate has been affirmed as GRAS and has established INS status, it has undergone a degree of scrutiny that supports its continued authorized use under prescribed conditions.

Regulatory Status Worldwide

In the United States, stearyl citrate is specifically listed in the Code of Federal Regulations at 21 CFR 184.1851, where it is affirmed as generally recognized as safe (GRAS) when used in food under conditions of current good manufacturing practice. The regulation describes stearyl citrate as a mixture of mono-, di- and tristearyl esters of citric acid and outlines its allowed uses in categories such as margarine, nonalcoholic beverages and fats and oils under typical practice, supporting its use as an antioxidant, emulsifier, sequestrant and surface-active agent. This regulatory listing reflects a safety determination by the U.S. Food and Drug Administration (FDA) based on evidence that the ingredient performs its technical functions without presenting harm under intended conditions of use. Internationally, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) evaluated stearyl citrate and assigned it an International Numbering System (INS) number of 484. JECFA’s evaluation included acceptable daily intake considerations, reflecting historical assessments of safety and functional necessity in food systems. National and regional regulatory frameworks may incorporate or reference JECFA evaluations or maintain their own assessments. Where a given jurisdiction has formally adopted a food additive regulation or listing for stearyl citrate, those specific allowances and any associated purity specifications or use conditions define the legal basis for its inclusion in food products.

Taste And Functional Properties

Stearyl citrate itself does not impart significant taste or aroma to food products and is considered largely neutral in sensory terms. Its functional properties are instead demonstrated through its interaction with other food components. As an emulsifier, stearyl citrate enables the formation of fine, stable dispersions of oil in water, which contributes to a smooth and uniform texture in products containing fat phases. It is soluble in lipid environments and exhibits limited water solubility, which aligns with its role in stabilizing oil-rich formulations and interfaces. In terms of stability, stearyl citrate is generally stable under typical food processing conditions, including moderate heat and shear, provided that conditions do not lead to excessive hydrolysis or degradation. Its surface-active properties enhance foaming and wetting in certain systems, although it is typically used in combination with other emulsifiers or stabilizers to achieve desired functional effects. Because it does not contribute off-flavors or aromas, stearyl citrate is suitable for use in a wide range of taste-sensitive applications such as beverages, dairy analogs and confections where maintaining the intended flavor profile is essential.

Acceptable Daily Intake Explained

An Acceptable Daily Intake (ADI) is a regulatory benchmark used to express the amount of a substance that can be ingested daily over a lifetime without appreciable health risk, based on available toxicological data and built-in safety factors. ADIs are typically established by expert committees such as JECFA, which review studies on absorption, metabolism, toxicity and long-term effects in animal models to derive conservative exposure limits. An ADI helps food manufacturers and regulators gauge whether typical dietary exposure to an additive remains within safe bounds given anticipated use levels and consumption patterns. For stearyl citrate, historical evaluations have referenced an ADI context reflecting careful consideration of toxicological findings and technological need. However, the specific numeric ADI value stated by JECFA reflects the parameters of that evaluation and may evolve with additional evidence or methodological updates. ADIs do not represent recommended intake levels but are safety thresholds underpinning regulatory approval and food additive use conditions. Meeting or staying below the ADI in a typical diet suggests that the additive’s presence in foods is consistent with established safety frameworks.

Comparison With Similar Additives

Stearyl citrate shares technological functions with other citrate-based and ester-type additives used in food systems. For instance, triethyl citrate also serves as an emulsifier and stabilizer in various food and beverage applications, helping to maintain uniform texture and prevent phase separation. Like stearyl citrate, triethyl citrate facilitates dispersion of lipid phases, although differences in molecular structure influence solubility and functional performance in specific formulations. Another related additive, isopropyl citrate, serves as both an emulsifier and chelating agent, helping stabilize products where metal ions might catalyze oxidation. While structurally similar, differences in the length and branching of alcohol-derived chains affect how these additives interact with fats, water and interfaces within complex food matrices. Compared with more traditional emulsifiers such as lecithin or mono- and diglycerides, citrate esters like stearyl citrate and its analogs often offer distinct lipophilic-hydrophilic balance that can be advantageous in emulsions with significant oil phases. Lecithin, a phospholipid, provides natural emulsifying properties and is often preferred where label-friendly or non-synthetic designations are desired, whereas citrate esters may be selected for specific technical performance. In sequestrant function, additives like EDTA (ethylenediaminetetraacetic acid) play a similar role in binding trace metals, but citrate esters often contribute both sequestrant and emulsifying functions. These comparisons illustrate how food formulators choose additives based on functional requirements, regulatory status and interaction with other ingredients.

Common Food Applications Narrative

Stearyl citrate finds its place in many formulated food products where emulsification and oxidative stability are important to product performance and consumer experience. In spreads and margarine-type products, it helps create and maintain stable fat-in-water dispersions that contribute to spreadability, mouthfeel and shelf stability. In beverage emulsions, particularly those that combine oil-soluble components with aqueous phases, stearyl citrate helps prevent phase separation over time, ensuring that products remain visually appealing and texturally consistent throughout their shelf life. In sauces, dressings and dairy analogs, the functional properties of stearyl citrate support texture uniformity and resistance to oil separation. Its antioxidant role contributes to extending the usable life of fat-containing products by limiting oxidative degradation that can lead to rancid flavors. Beyond traditional foods, stearyl citrate can also be used in certain confectionery and baked goods where lipid stabilization enhances quality and processing performance. Though not a primary flavoring ingredient, its presence enhances the overall integrity of complex formulations by supporting the desired balance of texture, appearance and oxidative stability.

Safety & Regulations

FDA

  • Approved: True
  • Regulation: 21 CFR 184.1851

EFSA

  • Notes: EFSA approval status not verified by authoritative deep link

JECFA

  • Year: 1973
  • Ins Number: 484
  • Adi Display: 0-50 mg/kg bw
  • Adi Mg Per Kg: 50

Sources

Comments

No comments yet. Be the first to share!