ALUMINUM CALCIUM SILICATE

CAS: 1327-39-5

Aluminum calcium silicate (CAS 1327-39-5) is a white inorganic anticaking agent used in table salt and other dry food products, evaluated by international committees and regulated under specific food additive standards.

What It Is

Aluminum calcium silicate is a white, fine inorganic compound identified by the Chemical Abstracts Service registry number 1327-39-5. It belongs to the family of silicate minerals and is commonly classified as an anticaking agent in food technology. In its pure form, it appears as a powder that assists in preventing clumping of powdered and granular food ingredients. The additive may also be referred to by other technical names that reflect its chemical composition, including calcium aluminosilicate and silicic acid aluminum calcium salt. These synonyms describe the underlying silicate structure composed of aluminum, calcium, silicon, and oxygen atoms arranged in a crystalline or amorphous matrix. Across regulatory databases and food additive listings, aluminum calcium silicate is grouped with other silicates that share similar functional properties. It is often designated within international additive numbering systems as INS 556, indicating its role as an anticaking agent used to ensure that powdered food products remain free-flowing during storage, handling, and consumer use. The substance is inert in terms of flavor contribution and does not significantly influence the sensory character of food products when used at approved levels. While its chemical identity is well established, the technical function in food formulations centers on physical performance rather than chemical reactivity. In addition to its role in food products, aluminum calcium silicate has applications outside of the food sector owing to its physical characteristics. It can be used in industrial materials, ceramics, and other non-food applications, but in the context of food usage, its classification is strictly tied to its ability to control moisture and improve the handling of dry ingredients. This multifunctionality within the broader class of silicate additives makes it a versatile component in dry food systems, where caking control is essential for product quality and stability.

How It Is Made

The manufacturing of aluminum calcium silicate involves combining sources of silica, aluminum, and calcium under controlled conditions to form a stable silicate matrix. At an industrial level, raw materials such as high-purity silica or clay minerals (which contain silicon and aluminum) are processed with calcium sources such as calcium hydroxide or calcium chloride. These components are reacted at elevated temperatures to facilitate the formation of the silicate structure. The reaction typically occurs in a furnace or kiln where heat encourages the fusion of silica and metal oxides into a homogeneous material. Once the initial silicate is formed, the material is ground and milled to achieve a fine, free-flowing powder that meets food-grade specifications. The milling step is critical because particle size and distribution influence the effectiveness of the additive as an anticaking agent. Finer particles have a larger surface area, enabling them to interact more effectively with moisture and other particles in a food matrix. Quality control measures during production often include physical tests for particle size distribution and chemical analysis to confirm the relative proportions of silicon dioxide, aluminum oxide, and calcium oxide within defined specifications. In regulatory monographs prepared by international food additive experts, such as those developed by JECFA, specifications for aluminum calcium silicate include limits on impurities like lead and fluoride to ensure that the final product meets purity requirements suitable for food use. These specifications also include tests for loss on ignition and solubility characteristics, which help confirm that the material complies with established criteria for food additives. The process from raw material to finished additive emphasizes controlled chemical reactions followed by physical processing steps that ensure the product is technically effective and safe for its intended use. The manufacturing pathways used in different jurisdictions may vary slightly based on local raw material availability and industrial practice, but the overarching goal is consistent: to produce a material that behaves reliably as an anticaking agent and meets all applicable safety and purity standards. Because aluminum calcium silicate is an inorganic mineral-based substance, its production does not involve biological or fermentation processes that are common with some other food additives. Instead, it relies on well-established inorganic synthesis and material processing techniques that have been optimized over decades in both food and industrial sectors.

Why It Is Used In Food

Aluminum calcium silicate is used in food primarily for its anticaking properties, helping to maintain the free-flowing nature of dry powdered and granular products. Moisture and environmental humidity can cause particles to clump together, leading to poor flow characteristics, caking in packaging, and inconsistent portioning. In applications such as table salt, baking mixes, and other dehydrated foods, these issues can compromise product quality and consumer experience. By incorporating an anticaking agent, manufacturers can improve the shelf stability and handling of products that are prone to moisture-induced agglomeration. Anticaking agents like aluminum calcium silicate function by adsorbing free moisture onto their surface, thereby reducing the water available to facilitate particle sticking. This physical interaction does not alter the food’s nutritional profile or flavor at typical usage levels. Instead, it ensures that the product remains easy to pour and measure, even under conditions of variable humidity. In food processing and packaging environments where consistent flow is crucial for automated filling lines, anticaking agents contribute to operational efficiency and reduced waste from clumped or adhered powders. In addition to flow enhancement, aluminum calcium silicate can help maintain product appearance and texture. Caking and lump formation detract from the desirable fine texture of many dry products, making them less appealing to consumers. By preventing aggregation, anticaking agents preserve the intended sensory experience of products such as table salt, powdered beverage mixes, and dry seasoning blends. This functional role supports both aesthetic and practical aspects of food quality. While its primary use is anticaking, aluminum calcium silicate is not a source of nutrients nor does it meaningfully affect the flavor profile of the foods in which it is used. Its selection in formulation is based on physical performance criteria rather than chemical reactivity, making it a specialized additive for maintaining product integrity. Because anticaking agents are used at relatively low levels and are not intended to interact chemically with other ingredients, their presence is largely unnoticed by consumers in terms of taste, aroma, or digestibility. Instead, the benefits are realized through improved consistency, process reliability, and overall product quality in dry food systems.

Adi Example Calculation

Because aluminum calcium silicate has an established designation of "ADI not specified," it is not appropriate to provide a numerical calculation example based on a numeric ADI. The designation means that international expert committees have determined that a numerical acceptable daily intake is not necessary due to the additive’s low toxicity and minimal absorption when consumed at levels consistent with its intended use as an anticaking agent. As a result, there is no numeric value against which to illustrate a calculation. Instead, the concept of an ADI not specified serves as an assurance that dietary exposure from regulated uses is not expected to pose a health concern. In contrast, when an additive does have a numerical ADI, hypothetical examples are often constructed to demonstrate how estimated intake compares to the permissible limit. For instance, such examples might assume a person’s body weight and typical consumption of foods containing the additive to illustrate whether intake remains below the specified threshold. Because no numeric ADI exists for aluminum calcium silicate, the relevant message for consumers and formulators is that regulatory authorities have assessed the additive as posing low toxicological concern at authorized levels, and companies are expected to formulate products in accordance with good manufacturing practice. It is also important to emphasize that regulatory determinations like "ADI not specified" do not imply that the additive can be used without limits. Rather, they underscore that its safety profile has been evaluated and that authorized use conditions, such as maximum levels or good manufacturing practice guidelines, are in place to ensure consumer protection. Manufacturers must adhere to these conditions when including aluminum calcium silicate in dry food products. The absence of a numerical ADI facilitates regulatory flexibility while maintaining safety oversight, reflecting the substance’s minimal dietary impact when used appropriately.

Safety And Health Research

The safety assessment of food additives like aluminum calcium silicate is grounded in evaluations of toxicological data, exposure estimates, and functional use patterns. International expert bodies such as the Joint FAO/WHO Expert Committee on Food Additives (JECFA) conduct systematic reviews of available studies and data to determine whether a substance raises concerns at levels consistent with intended dietary exposure. In the case of aluminum calcium silicate and certain other silicates, JECFA’s evaluation concluded that a numerical acceptable daily intake was not necessary because the additive exhibited low toxicity and did not pose a risk at levels encountered through typical use in food products. This conclusion is based on an extensive body of research on silicates and related mineral compounds, which generally exhibit minimal absorption from the gastrointestinal tract due to their insoluble nature. Because they pass through the digestive system largely unchanged, silicates have limited potential for systemic exposure. As a result, toxicological studies do not indicate significant hazards associated with oral ingestion at levels that would be encountered from normal use as an anticaking agent. However, regulatory evaluations continue to consider endpoints such as acute toxicity, subchronic toxicity, and potential for bioaccumulation, among other factors. It is important to distinguish between food additive safety and occupational exposure concerns. While the ingestion of aluminum calcium silicate as a food additive has been deemed of low toxicological concern, inhalation of fine mineral dust in industrial settings can pose respiratory risks to workers if appropriate controls are not in place. Such occupational safety considerations are addressed separately through workplace health regulations and are not indicative of the safety profile for dietary exposure. Overall, the safety research supporting the use of aluminum calcium silicate in food focuses on ensuring that typical consumption patterns do not lead to adverse health effects. The designation of a non-specified ADI by international expert committees reflects a consensus that, when used in accordance with regulatory approvals and good manufacturing practice, the additive does not contribute appreciably to health risk. Ongoing surveillance and research may continue to inform regulatory bodies, but the substance’s long history of use and evaluation provides a robust evidence base for its continued authorized use in applications where anticaking functionality is required.

Regulatory Status Worldwide

Aluminum calcium silicate is recognized under specific food additive regulations in the United States and is generally regarded as safe for its intended uses when used in accordance with good manufacturing practice. In the U.S., the Code of Federal Regulations Title 21 Part 182 lists aluminum calcium silicate as an anticaking agent that is permitted in foods such as table salt at levels consistent with good manufacturing practice. This regulatory listing provides a tolerance, which describes the maximum level at which the additive may be present in the finished food product without violating the regulation. The U.S. federal regulation specifically identifies a 2 percent tolerance for aluminum calcium silicate in table salt, meaning that the additive may be used up to that level when necessary to achieve its anticaking function. Internationally, food additive experts convened by the Food and Agriculture Organization of the United Nations and the World Health Organization through the Joint FAO/WHO Expert Committee on Food Additives (JECFA) have evaluated aluminum calcium silicate and related silicates. In these evaluations, the Committee established that a numerical acceptable daily intake (ADI) was not specified because the additive exhibited very low toxicity and, within the context of typical dietary exposure, did not raise concerns that would warrant a specific numeric limit. The Committee’s designation of a group ADI not specified for certain silicates reflects the conclusion that these substances are of low toxicological concern when used as intended. Other jurisdictions may recognize aluminum calcium silicate under their own food additive frameworks, often harmonizing with Codex Alimentarius standards and JECFA evaluations. In global food standards such as the Codex General Standard for Food Additives, aluminum calcium silicate is associated with an international numbering system identifier that indicates its function as an anticaking agent. However, not all jurisdictions may have explicit maximum use levels codified in their regulations, and where local regulations differ, food producers must ensure compliance on a market-by-market basis. Because regulatory frameworks are periodically updated, manufacturers and formulators should consult current regulatory texts in the regions where their products are distributed to confirm permissible uses.

Taste And Functional Properties

Aluminum calcium silicate itself is essentially tasteless and does not contribute perceivable flavor to foods when used within approved levels. This is an important characteristic for an anticaking agent because it must perform its physical role without imparting unwanted sensory attributes. As a mineral-based additive, its presence in the food matrix is designed to be neutral from a flavor standpoint, allowing other ingredients to define the overall sensory profile that consumers expect. Functionally, aluminum calcium silicate is highly effective at controlling the physical behavior of granular and powdered food materials. Its mechanism centers on managing moisture and surface interactions between particles. In environments where moisture can cause particle adhesion and clumping, anticaking agents with high surface area and adsorptive capacity like aluminum calcium silicate help keep particles discrete and free-flowing. This property is particularly valuable in food categories where precise dosing and consistent texture are required, such as table salt, powdered drink mixes, and dry seasoning blends. From a stability perspective, aluminum calcium silicate is chemically inert under typical food storage conditions. It does not readily dissolve in water or alcohol, which helps it maintain structural integrity and continue performing its physical role throughout the product’s shelf life. This insolubility also means that it does not readily release reactive ions or alter the food’s pH, further supporting its designation as a neutral functional ingredient. Its interaction with moisture is largely physical rather than chemical, involving the trapping or distribution of small amounts of water on its surface to prevent particle-particle bonding. In terms of heat stability, aluminum calcium silicate is robust under typical food processing temperatures because it is a mineral-based compound with a high melting point. It does not degrade or break down during common heat treatments such as drying or baking. Its physical form and function remain unchanged through such processes, ensuring continued efficacy in the finished product. Because it is not a source of flavor, color, or nutritional value, its functional contribution is evaluated solely based on how well it helps maintain product handling and appearance, making it a specialized tool in formulation rather than a multi-purpose additive.

Acceptable Daily Intake Explained

The concept of an acceptable daily intake (ADI) is used by food safety authorities to express the amount of a food additive that can be consumed every day over a lifetime without appreciable health risk. For additives like aluminum calcium silicate, which are poorly absorbed and exhibit low toxicity, international expert committees may determine that a numerical ADI is not necessary. In such cases, the designation of "ADI not specified" means that based on available data, the additive does not pose a hazard at levels consistent with its intended uses, provided that it is used in accordance with good manufacturing practice and regulatory allowances. When an ADI is defined numerically for an additive, it is typically expressed in milligrams of the additive per kilogram of body weight per day. Regulatory authorities use toxicological data, uncertainty factors, and exposure estimates to derive these values, ensuring a wide margin of safety for human consumption. In the case of "ADI not specified," the conclusion is that the substance’s low bioavailability and limited toxicity mean that exposures from normal dietary use are not expected to approach levels of concern. It is essential to recognize that an ADI is not a recommendation for consumption but a safety benchmark that guides regulatory decisions and permissible levels in foods. For aluminum calcium silicate, the absence of a specified numerical ADI reflects a determination that its use as an anticaking agent does not result in significant dietary exposure that would warrant numeric limits. This approach aligns with regulatory evaluations in jurisdictions where the additive is permitted, emphasizing that it should be used only to the extent necessary to achieve its technical function. Good manufacturing practice ensures that products are formulated with appropriate additive levels that do not exceed what is needed for physical performance, further supporting safety assessments. Consumers do not need to calculate their own intake relative to the ADI. Instead, regulatory authorities and food manufacturers share responsibility for ensuring that food products comply with established use conditions and safety standards. The designation of "ADI not specified" conveys confidence from expert evaluators that the additive’s use within authorized applications does not pose a health concern.

Comparison With Similar Additives

Aluminum calcium silicate belongs to a broader class of inorganic anticaking agents that are used to maintain the free-flowing nature of powdered and granular food products. Within this class, substances such as silicon dioxide, calcium silicate, and sodium aluminosilicate serve similar functional roles but differ in chemical composition and physical behavior. Silicon dioxide, for example, is a simple oxide of silicon that is often used in dry mixes and powdered beverages because of its fine particle size and high surface area, which provide effective moisture absorption. Like aluminum calcium silicate, silicon dioxide is chemically inert and exhibits low toxicity, but its efficacy can vary depending on the specific product matrix and environmental conditions. Calcium silicate is another widely used anticaking agent with a chemical composition that emphasizes calcium and silicate components. Compared to aluminum calcium silicate, calcium silicate may offer different moisture adsorption characteristics due to its distinct mineral structure. Sodium aluminosilicate, which contains sodium in addition to aluminum and silicon, is yet another anticaking option. The presence of sodium may influence properties such as hygroscopicity and interaction with other ingredients in specific food systems. Each of these additives is selected based on formulation needs, regulatory status in target markets, and performance criteria such as particle size distribution and moisture-binding capability. Despite their shared functional purpose, these anticaking agents are not interchangeable in all applications. For instance, the choice between aluminum calcium silicate and silicon dioxide may depend on the desired balance between flow enhancement and regulatory acceptance in particular jurisdictions. Some markets may have specific use conditions or labeling requirements that favor one additive over another. Manufacturers must consider these regulatory factors in tandem with technical performance to ensure that the selected agent aligns with both product quality goals and compliance obligations. Overall, the comparison among anticaking agents underscores that while they serve analogous roles in preventing caking and ensuring product handling quality, their chemical differences and regulatory allowances can influence formulation decisions. Understanding the properties and permitted uses of each agent helps food technologists and regulatory professionals make informed choices that support both product performance and adherence to food safety standards.

Common Food Applications Narrative

Aluminum calcium silicate finds application in a range of dry food products where control of moisture-induced clumping is essential for delivering consistent texture and ease of use. In the production of table salt, for example, anticaking agents are critical to ensuring that the salt crystals remain free-flowing in shakers and dispensers, particularly in humid conditions. Without an effective anticaking agent, table salt can absorb atmospheric moisture and form hard aggregates that are difficult to pour or sprinkle, detracting from consumer convenience. Beyond table salt, aluminum calcium silicate may be used in other powdered food categories where similar physical challenges arise. These include dry baking mixes, powdered beverage formulations, powdered seasonings, and spice blends. In each of these applications, the presence of an anticaking agent helps maintain the fine particulate structure that consumers associate with quality products. For example, in powdered beverage mixes, a uniform flow ensures that scoops of product deliver consistent volume and dissolve predictably when mixed with water or other liquids. In spice blends and seasoning mixes, anticaking agents help prevent the formation of hard lumps that can result from exposure to fluctuating temperatures and humidity during distribution and storage. A product that stays free-flowing is easier for consumers to measure, shake, and incorporate into cooking or direct consumption, enhancing the overall user experience. The contribution in these contexts is purely physical: it preserves the intended texture and usability of dry components without altering the food’s flavor or nutritional characteristics. Manufacturers select anticaking agents like aluminum calcium silicate based on performance requirements and regulatory compliance for the intended market. In regulated jurisdictions, usage levels and labeling must conform to specific standards that define acceptable inclusion rates and functional roles. In doing so, food producers balance technical performance with compliance obligations to ensure that products meet quality expectations and regulatory criteria in the regions where they are sold.

Safety & Regulations

FDA

  • Approved: True
  • Regulation: 21 CFR 182.2122

EFSA

  • Notes: EFSA e number and approval status not found in authoritative sources

JECFA

  • Notes: JECFA evaluation did not specify a numeric ADI and year not explicitly shown in d entry
  • Ins Number: 556
  • Adi Display: ADI not specified

Sources

Comments

No comments yet. Be the first to share!