IRON AMMONIUM CITRATE

CAS: 1185-57-5 ANTICAKING AGENT OR FREE-FLOW AGENT

IRON AMMONIUM CITRATE is a water-soluble iron(III) citrate complex used in food as an anticaking agent and nutrient supplement. It is authorized by specific food additive regulations when used according to prescribed conditions.

What It Is

IRON AMMONIUM CITRATE is an inorganic coordination complex that forms when ferric iron (Fe3+) is chelated by citrate ligands and paired with ammonium counterions to produce a stable, water-soluble salt. It is identified chemically by CAS Number 1185-57-5 and appears as a green to brown powder or crystalline solid with a slight ammonia odor. In the context of food formulation, IRON AMMONIUM CITRATE functions principally as an anticaking agent or free-flow agent, preventing clumping and improving the handling properties of powdered and granular food ingredients. The citrate ligand system chelates iron(III), which stabilizes it in solution and makes it more compatible with food matrices than non-chelated iron salts. The compound appears on regulatory lists under its various synonyms, including AMMONIUM IRON(III) CITRATE and FERRIC AMMONIUM CITRATE. In some regulatory systems, it is assigned INS number 381 as part of the international food additive numbering scheme, indicating its role as an anticaking agent and nutrient supplement in foods. This multifaceted identification helps food scientists and regulatory professionals cross-reference the compound across different chemical and food additive databases and ensure consistent use and labeling in finished products. IRON AMMONIUM CITRATE is valued in food applications for its ability to contribute trace iron while maintaining product stability and flow properties, but it must be used within regulated limits to ensure safety and compliance with food additive legislation.

How It Is Made

The manufacture of IRON AMMONIUM CITRATE begins with the controlled reaction of a ferric iron source with citric acid under aqueous conditions. Citric acid, a naturally occurring tricarboxylic acid, provides multiple coordination sites that bind strongly to ferric iron (Fe3+), forming a chelate complex. Ammonium hydroxide or another suitable ammonium source is then introduced to neutralize the acid and support the formation of the ammonium salt form of the iron citrate complex. As the solution chemistry evolves, conditions such as temperature, pH, and stoichiometric ratios are managed to produce a consistent product with desired hydration and composition. The resulting mixture is concentrated, often through evaporation, to yield a syrupy intermediate that is subsequently dried to a solid. Depending on the specific stoichiometry and processing conditions, the finished product may crystallize as a green or brown hydrated form of IRON AMMONIUM CITRATE. Industrial production emphasizes purity and compliance with food-grade specifications, which include limits on heavy metals and other potential contaminants. For food applications, manufacturers will often follow compendial standards such as those in the Food Chemicals Codex (FCC) or other recognized quality specifications to assure compliance with regulatory and safety requirements. Water solubility, moisture content, and particle size distribution are typical quality attributes verified in finished lots of IRON AMMONIUM CITRATE destined for food use. The production process does not involve complicated organic synthesis steps; rather it leverages classic inorganic salt formation and coordination chemistry principles to generate a technically functional food additive.

Why It Is Used In Food

Food technologists incorporate IRON AMMONIUM CITRATE into food formulations primarily because of its functional properties as an anticaking agent or free-flow agent. Many powdered or crystalline food ingredients, such as salt, powdered drink mixes, and dry seasoning blends, are prone to absorbing moisture and forming clumps during storage and handling. This can lead to inconsistency in product texture, packaging challenges, and reduced consumer acceptability. By integrating a controlled amount of IRON AMMONIUM CITRATE into these matrices, manufacturers improve flow characteristics and reduce the tendency for particles to stick together, ensuring that the final product retains a uniform physical state. Beyond anticaking functionality, the iron component can contribute trace amounts of nutritive iron, which may be beneficial in formulations where micronutrient fortification is a consideration. However, its primary authorization in many jurisdictions is tied to its role in supporting manufacturing and quality attributes rather than nutritional enhancement. Formulators also value IRON AMMONIUM CITRATE for its compatibility with a broad range of food ingredients and its relatively neutral sensory impact when used at regulated levels, meaning it does not impart strong tastes or colors that would detract from the intended food profile. Careful formulation practices are vital because excessive inclusion can alter sensory properties or exceed regulatory limits. For example, in salt intended for human consumption, specific regulations limit the maximum allowable amount to ensure that the additive performs its intended anticaking function without contributing excessive iron or affecting product attributes. This combination of technical performance and regulatory recognition makes IRON AMMONIUM CITRATE a practical choice in many dry food systems that demand consistent quality and ease of processing.

Adi Example Calculation

To illustrate how intake guidance might be considered in practical terms, consider a hypothetical adult consumer with a body weight of 70 kilograms. If an international intake guidance value for iron from additive sources is expressed as a provisional limit on elemental iron, one might calculate total allowable intake by multiplying the guidance figure by body weight. For example, if the guidance expressed a tolerable intake of 0.8 milligrams of elemental iron per kilogram of body weight, this would translate to 56 milligrams of elemental iron per day for a 70-kilogram adult. In such a scenario, the contribution of IRON AMMONIUM CITRATE to total dietary iron intake would be evaluated alongside other dietary sources of iron, such as fortified cereals or naturally iron-rich foods. It is critical to emphasize that this calculation is illustrative and not a recommendation for individual consumption or supplement use. Actual intake guidance values are derived through detailed risk assessment and may vary by regulatory authority. The purpose of such examples is to demonstrate how body weight and regulatory intake limits interact in exposure assessments. In practice, exposure to additives like IRON AMMONIUM CITRATE from food is typically a small fraction of overall iron intake due to the low usage levels in functional applications, such as anticaking, and dietary iron intake from other sources often predominates. Nonetheless, using intake figures helps regulators and manufacturers ensure that aggregate exposure remains within considered safe boundaries for the general population.

Safety And Health Research

The evaluation of IRON AMMONIUM CITRATE by regulatory bodies centers on its safety when used in accordance with defined conditions of use, rather than on intrinsic pharmacological effects. Regulatory safety assessments consider multiple lines of evidence, including toxicological profiles of iron compounds and historical consumption data when available. Iron is an essential trace mineral required for normal physiological functions, but excess iron intake can lead to adverse effects, particularly in individuals with conditions that affect iron metabolism. The JECFA evaluation classifies IRON AMMONIUM CITRATE in the broader context of iron-containing additives and provides a provisional tolerable intake level expressed on an elemental iron basis. Such assessments help regulators frame acceptable limits for additive use that balance potential nutritional benefit with the avoidance of excess exposure. Although food additive safety reviews include examination of available toxicology studies and exposure estimates, specific clinical research demonstrating health outcomes directly attributable to IRON AMMONIUM CITRATE at food additive levels is limited, reflecting its relatively low use levels and regulatory constraints. Safety research for additives often emphasizes endpoints such as genotoxicity, chronic toxicity, and reproductive effects in standardized laboratory models, but for compounds that break down into biologically familiar components—like citrate and iron—the focus is on ensuring that total dietary iron exposure remains within acceptable bounds. In industrial and occupational contexts, safety data sheets for IRON AMMONIUM CITRATE provide guidance on handling and exposure controls to minimize inhalation or dermal contact risks, but these considerations are separate from food safety evaluations and pertain to manufacturing environments. Overall, regulatory frameworks that incorporate IRON AMMONIUM CITRATE into food use authorization are designed to ensure that its inclusion at permitted levels does not meaningfully increase health risks while supporting desired technological functions in food products.

Regulatory Status Worldwide

In the United States, IRON AMMONIUM CITRATE is specifically listed in the Code of Federal Regulations as a permitted food additive when used as prescribed. According to 21 CFR 172.430, the compound, identified as the chemical green ferric ammonium citrate, may be used as an anticaking agent in salt for human consumption subject to a maximum level of 25 parts per million in the finished product. This regulation also requires that labeling of the additive include adequate directions for achieving compliance with the prescribed limitations, which helps ensure that manufacturers maintain usage within safe and effective bounds. The inclusion of IRON AMMONIUM CITRATE in this regulatory provision reflects a formal evaluation by the U.S. Food and Drug Administration (FDA) that the additive performs its intended technological function without posing undue risk when used appropriately. In addition, IRON AMMONIUM CITRATE appears in other sections of U.S. food additive listings that describe manufacturing practice usage and specifications, highlighting its recognized status within the broader regulatory framework governing food ingredients. Beyond the United States, international authorities such as the Joint FAO/WHO Expert Committee on Food Additives (JECFA) have reviewed IRON AMMONIUM CITRATE and assigned it the international food additive number 381. JECFA evaluations often include assessments of possible daily intake and technical function, which inform regulatory decisions in multiple countries and regional jurisdictions. While specific usage authorizations and permissible levels can vary by region, the presence of IRON AMMONIUM CITRATE on JECFA’s list indicates a foundation of technical acceptance and risk assessment at an international level. In many national food regulations that reference or adopt JECFA specifications, this compound is accepted for similar functional uses, often with defined limits that mirror those in established regulatory systems. Manufacturers seeking to market foods containing IRON AMMONIUM CITRATE should consult local and regional food additive regulations to confirm compliance with applicable requirements, as these can differ in detail across jurisdictions.

Taste And Functional Properties

In general, IRON AMMONIUM CITRATE exhibits minimal impact on the taste profile of food products when used at levels permitted by regulatory agencies. At the low concentrations typical of anticaking applications, any inherent metallic or slightly acidic notes from the iron-citrate complex are largely undetectable in the finished product. Sensory evaluation studies conducted by manufacturers and food scientists suggest that properly formulated products containing IRON AMMONIUM CITRATE do not exhibit off-flavors attributable to the additive, which makes it suitable for inclusion in a variety of dry mixes and seasoning systems. From a functional perspective, IRON AMMONIUM CITRATE dissolves readily in water, which distinguishes it from less soluble iron salts. This high water solubility enhances its ability to distribute uniformly throughout aqueous solutions and suspensions, making it a versatile ingredient in both dry and reconstituted food products. Because the compound contains chelated iron, it is moderately stable across a range of pH values typically encountered in food formulations, but extreme pH conditions can affect the integrity of the citrate complex and, in turn, the functional performance. Heat stability is another relevant functional attribute; although IRON AMMONIUM CITRATE remains intact at temperatures encountered during typical food processing, prolonged exposure to high heat can lead to degradation of citrate ligands and changes in color due to iron redox chemistry. Food scientists consider these factors when selecting IRON AMMONIUM CITRATE for a specific application, ensuring that processing conditions do not compromise performance. Overall, the sensory neutrality and functional flexibility of IRON AMMONIUM CITRATE contribute to its utility in enhancing product flow, stability, and manufacturing efficiency without detracting from consumer sensory experience.

Acceptable Daily Intake Explained

An Acceptable Daily Intake (ADI) or similar intake guidance provides a context for understanding how much of a substance can be consumed daily over a lifetime without appreciable health risk. For nutrient-containing additives such as IRON AMMONIUM CITRATE, intake considerations focus on the contribution of elemental iron rather than the compound as a whole. International expert panels like the Joint FAO/WHO Expert Committee on Food Additives (JECFA) assess available toxicological and nutritional data to derive a tolerable intake level expressed on an iron-equivalent basis. In this case, JECFA’s grouping of iron-containing additives yields a provisional tolerable intake figure (expressed as elemental iron) intended to encompass total dietary exposure from all sources. This framework helps regulators and manufacturers ensure that the contribution of food additives to overall iron intake remains consistent with established nutritional requirements and safety margins. It is important to recognize that this intake guidance is not a recommended level to achieve or exceed; rather, it serves as a conservative boundary designed to protect vulnerable populations and account for uncertainties in data. The concept of ADI accommodates typical variations in consumption patterns and body weights across populations, and it reflects the fact that iron has both essential roles and potential toxicity at high levels. Using intake guidance allows food formulators and public health officials to model exposure scenarios and confirm that the combined intake from fortified foods, naturally iron-containing ingredients, and supplements stays within a range considered safe by expert review. Maintaining exposure within this range supports the dual goals of supplying necessary micronutrients without imposing undue risk, especially in populations at risk of iron overload or with unique metabolic considerations.

Comparison With Similar Additives

Comparing IRON AMMONIUM CITRATE with other anticaking agents and iron-containing additives highlights similarities and differences in function, sensory impact, and regulatory context. For example, silicon dioxide is a widely used anticaking agent that functions by adsorbing moisture and stabilizing powder flow, but unlike IRON AMMONIUM CITRATE, it does not contribute a nutrient element to the diet. Silicon dioxide’s inert nature and broad regulatory acceptance make it suitable for many powdered ingredients, yet it lacks the dual nutrient-functional character of IRON AMMONIUM CITRATE. Another comparison is with calcium silicate, which also serves as a moisture absorber and flow aid but again does not supply micronutrients. In contrast, other iron-containing additives such as ferrous sulfate provide a concentrated source of elemental iron and are used primarily for fortification or supplementation rather than anticaking. Ferrous sulfate’s stronger taste and lower solubility in certain matrices mean it is not typically used for flow enhancement in dry mixes, as IRON AMMONIUM CITRATE is. Similarly, chelated iron compounds like ferrous gluconate offer enhanced bioavailability in nutritional applications but differ in functional behavior and regulatory status compared with IRON AMMONIUM CITRATE. These comparisons illustrate that while several additives may address specific technical needs, the particular chemical structure of IRON AMMONIUM CITRATE enables a unique combination of free-flow functionality and trace nutrient contribution that can be advantageous in certain food systems. Choosing among these additives depends on formulation goals, regulatory allowances, and sensory considerations, and each must be evaluated within its specific functional niche.

Common Food Applications Narrative

IRON AMMONIUM CITRATE finds its way into a variety of commercially available foods where maintaining free-flow characteristics and preventing clumping or caking are essential to product quality. One of the most common applications is in table salt and salt-based seasoning blends, where moisture absorption can quickly lead to particle agglomeration if not properly managed. By including a carefully measured amount of IRON AMMONIUM CITRATE in these formulations, manufacturers ensure that salt pours freely from shakers, packets, and dispensers, providing the consistent experience consumers expect. Beyond simple salt, more complex powdered products such as spice mixes, dry rubs, and refrigerated baking mixes also benefit from the anticaking effects of this additive, which preserves the fine, granulated texture necessary for predictable performance in cooking and baking. Dry drink mixes and beverage powders are another key category where IRON AMMONIUM CITRATE helps maintain a uniform dispersion of ingredients and reduces the formation of hard clumps that can resist rehydration. In industrial-scale food production, the inclusion of anticaking agents like IRON AMMONIUM CITRATE supports automated processing, packaging, and filling operations by reducing downtime and product waste associated with clogged equipment. When combined with standard good manufacturing practices and environmental controls such as humidity management, IRON AMMONIUM CITRATE contributes to the overall robustness of dry food supply chains. Although it is used in relatively small amounts compared with major ingredients like flour or sugar, its presence can significantly enhance product handling and consumer satisfaction. Because the additive carries iron, some fortified cereal and nutrition-enhanced formulas may also use this compound to deliver trace iron, though its role in such products is secondary to its physical functionality. Across all applications, manufacturers adhere to regulated usage limits to ensure that the additive remains within safe and acceptable levels in the final food product, reflecting a balance of technical benefit and consumer protection.

Safety & Regulations

FDA

  • Approved: True
  • Regulation: 21 CFR 172.430

EFSA

  • Notes: No specific EFSA evaluation deep link available

JECFA

  • Year: 1985
  • Ins Number: 381
  • Adi Display: Provisional tolerable intake on elemental iron basis

Sources

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