CALCIUM CITRATE

CAS: 813-94-5 FIRMING AGENT, NUTRIENT SUPPLEMENT, PH CONTROL AGENT, SEQUESTRANT

Calcium citrate is the calcium salt of citric acid used in foods as a firming agent, nutrient supplement, pH control agent, and sequestrant with regulatory allowances in key systems.

What It Is

Calcium citrate is a chemical substance composed of calcium bound to citrate anions, recognized for its use in the food industry as a firming agent, nutrient supplement, pH control agent, and sequestrant. It appears as a white, usually crystalline powder and can exist in hydrated forms, often described as tricalcium citrate in its food applications context. Calcium citrate carries the CAS number 813-94-5 and is identified under the International Numbering System for Food Additives as INS 333 in the Joint FAO/WHO Expert Committee on Food Additives (JECFA) database, where it is classified among acidity regulators and sequestrants evaluated historically. JECFA evaluations indicate that it was reviewed and specified for use as a food additive, and at the time of its evaluation, the Acceptable Daily Intake (ADI) was designated as "not limited" reflecting a long-standing regulatory perspective where toxicological data did not establish a numerical limit at the time of assessment. This designation means that for the purposes of safety assessment during JECFA’s review, the committee did not identify a specific intake threshold of concern under typical exposure conditions, consistent with regulatory frameworks of the period. Calcium citrate’s functional classes align with its technical roles in food systems including stabilizing, mineral fortification, and acidity adjustment. Its multiple functional designations and established regulatory listings have made it a widely recognized additive across regions that adopt Codex Alimentarius–aligned food additive listings and national regulations.

How It Is Made

Industrial production of calcium citrate typically begins with citric acid, which is produced commercially by fermentation processes using microbial strains such as Aspergillus niger. The citric acid solution is neutralized with a calcium source, often calcium hydroxide or calcium carbonate, resulting in the precipitation of calcium citrate. The precipitate is then separated from the liquid phase, washed, and dried to obtain the food-grade compound. This basic chemistry approach has been described in chemical industry resources and aligns with general manufacturing principles for citrate salts. After isolation, the product is milled and processed to meet food-grade specifications, including criteria for purity, moisture content, and absence of certain contaminants, such as heavy metals and insoluble material, as is typical for additives intended for human consumption. Food Chemical Codex standards have historically been referenced in regulatory contexts to define the purity and identity of compounds like calcium citrate when used as a direct food substance in the United States. Variations in hydration state (e.g., tetrahydrate forms) are acknowledged in regulatory definitions, and manufacturing processes control such variables to achieve formulations intended for consistent functional performance in foods. The end result is a stable, dry powder suitable for incorporation into a wide range of food products, often requiring compliance with good manufacturing practice to ensure that the additive performs as intended in finished foods.

Why It Is Used In Food

Calcium citrate serves several technological functions in food formulation. As a firming agent, it can contribute to the texture stability of products like canned vegetables and processed fruit preparations, where it helps maintain structural integrity during processing and storage. As a sequestrant, it binds metal ions that could otherwise destabilize food components or affect color and flavor, improving product consistency. Its role as a pH control agent allows formulators to adjust acidity to support flavor profiles, inhibit microbial growth, or optimize conditions for other ingredients to function effectively. Additionally, calcium citrate acts as a nutrient supplement by contributing calcium, an essential mineral, which can be a desirable label claim in fortified foods and beverages. These multifunctional uses reflect its versatility, enabling product developers to achieve both technological and nutritional objectives in various categories of processed foods. Its inclusion must be consistent with regulatory allowances and good manufacturing practice, where the quantity added is the minimum necessary to achieve the intended effect, thereby aligning technical function with safe use in food systems.

Adi Example Calculation

To illustrate how regulatory ADI frameworks work in general, consider a hypothetical person weighing 70 kilograms. An ADI expressed as an amount per kilogram of body weight allows calculation of total allowable intake by multiplying the ADI value by body weight. For example, if an additive had an ADI of 10 milligrams per kilogram body weight, a 70-kilogram person could be estimated to safely consume 700 milligrams of that additive per day on a lifetime basis without expected adverse effects. Calcium citrate’s historical JECFA designation of “not limited” indicates that regulators did not set a numeric ADI based on available data for typical food uses, but the conceptual approach to ADI calculations illustrates how safety factors and exposure assessments support regulator decisions and help frame consumer understanding of intake metrics.

Safety And Health Research

Regulatory evaluations of calcium citrate focus on the safety of its use as a food additive within technological and nutritional contexts. JECFA’s historical evaluation designated the ADI as not limited, reflecting a regulatory conclusion at the time that typical intakes from food additive uses did not raise safety concerns based on the data reviewed. The designation “not limited” does not imply unrestricted use in all contexts but indicates that the compound did not require a numerical ADI limit under the conditions assessed. Safety assessments generally consider factors such as genotoxicity, systemic toxicity, and long-term exposure across populations, with regulators incorporating evidence from chemical composition, metabolism, and functional roles in foods. National authorities may also account for calcium citrate’s contribution to overall dietary calcium intake when evaluating safety and labeling requirements. The GRAS listing in the United States reflects a regulatory determination of safety when used as intended, and in other jurisdictions, food additive authorizations incorporate similar safety assessments. Overall, regulatory and scientific bodies that oversee food additive approvals have established frameworks to ensure that multifunctional compounds like calcium citrate are evaluated against criteria that account for both technological need and consumer safety.

Regulatory Status Worldwide

In the United States, calcium citrate is affirmed as a direct food substance and generally recognized as safe (GRAS) when used in accordance with current good manufacturing practice under 21 CFR 184.1195, which defines its identity, preparation, and conditions of use. The CFR entry indicates that it may be used with no limitation other than good manufacturing practice and notes its use in general foods and infant formulas. This regulatory citation reflects official codified allowance for calcium citrate’s use as a food additive. In international contexts, calcium citrate is recognized in the JECFA database under the INS number 333, where its functional classes include acidity regulator, firming agent, and sequestrant, and the committee historically designated the ADI as not limited, indicating a lack of concern at evaluated levels. In the European Union, additives like calcium citrates are listed with an E number (E333) and subject to conditions outlined in the Union list of food additives, which is accessible through the European Commission’s database for food improvement agents and managed with EFSA scientific advice. While the EU system requires authorization of additives with defined E numbers, credible sources list calcium citrates under E333, implying recognized status within the additive framework. These regulatory listings illustrate how calcium citrate is integrated into food laws and standards across key markets, with specific conditions governing its safe and appropriate inclusion in food products.

Taste And Functional Properties

Calcium citrate is generally tasteless to mildly saline and does not impart strong flavors at the levels used in food applications. Its functional behavior in aqueous systems includes buffering capacity, which helps moderate pH changes when acids or bases are present, contributing to product stability and predictable processing outcomes. In terms of physical performance, calcium citrate has limited solubility in water compared to some other calcium salts, which can influence its effectiveness as a fortificant in beverages versus solid or semi-solid foods; formulators account for this when selecting calcium sources. The compound’s ability to interact with metal ions through chelation contributes to its sequestrant role, helping prevent oxidative changes that may compromise quality. Temperature and pH conditions affect its functional properties, and within typical food processing ranges, it remains stable, allowing it to be used in products subjected to heat treatments like pasteurization. These sensory and functional attributes, including its minimal flavor impact and compatibility with diverse processing conditions, make it suitable for a broad range of formulations where calcium addition and acidity regulation are desired.

Acceptable Daily Intake Explained

An Acceptable Daily Intake (ADI) is a parameter established by expert panels to describe the amount of a substance that can be consumed daily over a lifetime without appreciable risk, expressed per kilogram of body weight. For calcium citrate, JECFA’s evaluation assigned an ADI of “not limited,” meaning that data available at the time did not lead to establishment of a specific numeric intake limit for its use as an additive, a conclusion often reached when toxicity data do not indicate concern at typical exposure levels. This designation does not suggest unrestricted use in food formulations but reflects a regulatory assessment that normal use levels under good manufacturing practice are not expected to pose safety issues. Regulators set conditions of use, such as defining the functional classes and context of application, to align technical use with safe consumer exposure. Consumers may encounter calcium citrate across multiple food products, but the contribution from additive use is typically small compared with dietary calcium intake from natural sources, making regulatory evaluations focused on cumulative exposure within the context of functional use rather than standalone consumption thresholds.

Comparison With Similar Additives

Calcium citrate can be compared with other calcium salts and citrate-based additives used in food systems. For example, sodium citrate (often listed as INS 331) functions predominantly as an acidity regulator and sequestrant with high solubility, making it useful in beverages and confections where rapid dissolution and pH control are priorities. In contrast, calcium citrate’s lower solubility limits its effectiveness in certain liquid systems but makes it suitable for fortification in solid and semi-solid foods where calcium delivery is desirable. Another related additive is calcium lactate (INS 327), which also serves as a firming agent and calcium source, with different solubility characteristics and sensory profiles that influence formulation choices. Citric acid itself (INS 330) is widely used as an acidity regulator and flavoring agent, but unlike calcium citrate, it does not contribute significant calcium content. These comparisons highlight functional differences among additives that share structural similarities or related roles, guiding formulators to choose appropriate ingredients based on product requirements.

Common Food Applications Narrative

Calcium citrate finds widespread application in many categories of processed foods where it contributes both technological and nutritional benefits. In fruit and vegetable products, such as canned fruits, vegetable preparations, and salads with dressings, calcium citrate reinforces tissue structure, helping retain firmness during thermal processing and storage. It is also used in dairy and dairy-alternative beverages as a source of calcium to support fortification efforts and align with consumer demand for nutrient-enriched products. Baked goods and grain-based foods can incorporate calcium citrate as part of mineral fortification strategies, where it delivers calcium without significantly affecting flavor or texture. Beverage formulators incorporate it to adjust acidity and provide a soluble source of calcium in products like sports drinks and fortified waters, where mineral content is a key marketing point. In confectionery and snack applications, calcium citrate can play a role in pH control and shelf-life stability, demonstrating its multifunctional nature across product lines. These broad application contexts illustrate how calcium citrate is chosen for its ability to meet multiple product formulation needs, from enhancing nutritional profiles to maintaining quality attributes in finished foods, while adhering to established food additive regulatory frameworks in jurisdictions that permit its use.

Safety & Regulations

FDA

  • Approved: True
  • Regulation: 21 CFR 184.1195

EFSA

  • Notes: EFSA authorization conditions not explicitly verified
  • E Number: E333

JECFA

  • Notes: JECFA evaluation year not verified on source
  • Ins Number: 333
  • Adi Display: NOT LIMITED

Sources

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