CALCIUM HYDROXIDE

CAS: 1305-62-0 FIRMING AGENT, NUTRIENT SUPPLEMENT, PH CONTROL AGENT, PROCESSING AID

Calcium hydroxide (CAS 1305-62-0) is a food-grade firming agent and pH control additive permitted by regulators under certain conditions of good manufacturing practice.

What It Is

Calcium hydroxide, also known as slaked lime, hydrated lime, milk of lime, or calcium hydrate, is an inorganic compound with the chemical formula Ca(OH)2. It is recognized in food additive regulations under identifiers that include CAS 1305-62-0 and listed in regulatory references such as 21 CFR 184.1205 in the United States. Calcium hydroxide functions technologically in foods primarily as a firming agent, nutrient supplement, pH control agent, and processing aid. As a firming agent it helps maintain tissue firmness in fruits and vegetables during processing, and as a pH control agent it adjusts acidity or alkalinity to desired levels in various formulations. It also contributes calcium ions to formulations as part of nutrient fortification strategies. Calcium hydroxide’s applications span a wide range of food types, and its inclusion in regulatory frameworks reflects its longstanding use in multiple food processes under good manufacturing practice conditions. The compound is recognized in additive databases such as the Codex General Standard for Food Additives where it appears alongside functional classifications that support its technical roles in processed foods under controlled use conditions. Regulatory listings underscore its acceptance as a processing ingredient with specific technological benefits when used appropriately.

How It Is Made

Calcium hydroxide is manufactured by hydrating calcium oxide, commonly called quick lime, which is derived from the calcination of limestone (calcium carbonate). The calcination process involves heating limestone at high temperatures to produce calcium oxide, which is then combined with water in a controlled reaction to yield calcium hydroxide, often referred to as slaked lime. The resulting product typically appears as a white, crystalline powder or fine granules with alkaline properties. In food-grade production, the material is processed to meet specifications for purity and identity as outlined in compendia such as the Food Chemicals Codex. These specifications ensure that impurities such as heavy metals or other contaminants remain within defined limits to minimize potential hazards when used in food processing. Calcium hydroxide’s production steps are well established and have been refined over decades to support its use in food and industrial applications. Good manufacturing practices are applied to ensure the final material is suitable for its intended food technology functions without introducing unintended risks. Calcium hydroxide exhibits low solubility in water, forming an alkaline solution, and this property is leveraged in various applications including pH adjustments and tissue-firming processes. Industrial production often includes quality control measures such as testing for identity, composition, and absence of critical impurities to align with food-grade standards.

Why It Is Used In Food

Calcium hydroxide is employed in food processing for several technological reasons tied to its chemical properties and functional benefits. As a firming agent, it helps maintain the structural integrity of plant tissue during thermal processing, thereby preserving texture in canned vegetables and fruit products. Its role as a pH control agent allows formulators to regulate acidity levels, which can influence texture, stability, and microbial growth in certain products. Calcium hydroxide also acts as a processing aid by participating in specific food preparation steps, such as nixtamalization of maize where the alkaline solution helps loosen hulls and improve dough handling properties. Additionally, the compound provides a source of calcium, which can contribute to nutrient supplementation in fortified products, although the extent of nutritional impact depends on formulation and regulatory context. The use of calcium hydroxide in sugar refining processes demonstrates its utility in clarifying raw juices and adjusting pH during sugar manufacture. Across these diverse roles, its inclusion in food formulations is driven by the need to achieve specific technological outcomes under defined conditions of use. Regulatory frameworks often reference its use under good manufacturing practice, indicating that it should be used in a manner that is technologically justified and does not compromise food quality or safety.

Adi Example Calculation

A hypothetical calculation to illustrate the ADI concept involves an ADI value expressed for an additive in milligrams per kilogram of body weight per day. For example, if a regulatory body were to establish an ADI of X mg per kg body weight per day for a food additive, an individual weighing Y kg would have a theoretical daily exposure limit of X multiplied by Y. However, because calcium hydroxide’s regulatory references focus on use under good manufacturing practice rather than specifying a numeric ADI in commonly available summaries, providing a specific numeric example tied to a confirmed ADI is not appropriate without a directly d value from authoritative evaluation documents. The principle remains that exposures should remain within levels considered safe based on regulatory assessments and technological necessity.

Safety And Health Research

Regulatory bodies evaluate food additives based on toxicological data, human exposure estimates, and acceptable use conditions to determine safety. For calcium hydroxide, the U.S. FDA’s listing in 21 CFR 184.1205 reflects a determination that the compound meets specific specifications and does not raise safety concerns when used under good manufacturing practice conditions for its intended technological functions. Internationally, its listing in the Codex General Standard for Food Additives (GSFA) similarly signals acceptance by member countries with guidance oriented toward conditions of use rather than strict numerical limits, indicative of a risk assessment process that supports safety at typical use levels. Toxicological studies on calcium hydroxide and related alkaline compounds examine endpoints such as irritation potential and systemic effects, and these data inform safety assessments. In general, regulatory evaluations consider the balance between technological need and potential exposure, and whether anticipated intake from foods remains within boundaries considered to pose no concern. While calcium hydroxide is alkaline and can irritate tissues at high concentrations, at levels used for technological effects in food processing the exposure is controlled and risk remains low. The emphasis on good manufacturing practice is a key aspect of ensuring that usage does not lead to unintended consumer exposure beyond what is considered safe based on available data. Ongoing monitoring and specification updates by authorities and expert committees help maintain safety oversight.

Regulatory Status Worldwide

In the United States, calcium hydroxide is referenced in 21 CFR 184.1205 as a substance that meets specifications of compendial standards and may be used in food under conditions of current good manufacturing practice. This regulatory citation indicates that it is permitted for direct addition to food when used appropriately, and no numerical use limitations are specified beyond good manufacturing practice in that section. Calcium hydroxide also appears in regulatory listings as generally recognized as safe (GRAS) for food use by the U.S. Food and Drug Administration when added directly to food and animal feed under appropriate practices as noted in related regulations. Internationally, the Codex General Standard for Food Additives (GSFA) includes calcium hydroxide in food additive Table 3, permitting its use in foods under conditions of good manufacturing practice across a variety of food categories according to codified provisions. Calcium hydroxide is listed with an INS number of 526 in the Codex GSFA framework where it may be applied as an acidity regulator and other functional classes in accordance with internationally recognized standards. This inclusion reflects a broad consensus among member countries that the substance’s use is technologically justified and consistent with global food safety principles. Regulatory frameworks emphasize good manufacturing practice rather than numerical limits for many of these applications, underscoring the importance of process control and formulation context in ensuring safe and effective use.

Taste And Functional Properties

Calcium hydroxide in its food-grade form is a white, odorless powder with mild alkaline taste when present in solutions at detectable levels. Its alkaline nature means that in aqueous solutions it can raise pH, which is useful when balancing acidity or creating an environment that favors certain chemical reactions during processing. Functionally, calcium hydroxide has limited solubility in water, producing a high pH solution that interacts predictably with acidic components in food matrices. This behavior supports its use in texture modification, such as firming or strengthening tissues in processed vegetables or fruit, and in dough systems where alkaline conditions affect gluten properties and enzyme activity. The sensory impact is minimal at concentrations typically used for technical functions, although formulations must account for its alkaline taste when designing flavor profiles. Calcium hydroxide’s stability in dry form and compatibility with a range of food ingredients contribute to its utility in processing operations that involve heat, pH shifts, and interaction with other components. Its sustained functional performance under various process conditions makes it a useful ingredient in applications where physical and chemical properties must be carefully controlled for desired product attributes.

Acceptable Daily Intake Explained

Acceptable daily intake (ADI) is a regulatory concept that represents an estimate of the amount of a substance that can be consumed daily over a lifetime without appreciable health risk, taking into account available toxicological data and safety factors. For many food additives, an ADI is established by expert bodies such as the Joint FAO/WHO Expert Committee on Food Additives (JECFA) based on comprehensive evaluations. In the case of calcium hydroxide, international frameworks such as the Codex General Standard for Food Additives include its use under conditions of good manufacturing practice, and regulatory listings focus on use conditions rather than specifying a numeric ADI in some cases. When ADIs are not explicitly listed within authoritative publications, this reflects that risk assessments have concluded that exposure at use levels consistent with good manufacturing practice does not raise safety concerns. ADIs help food producers and regulators align formulation practices with consumer safety expectations and serve as benchmarks for evaluating exposure from multiple sources. They do not represent recommended intake levels but rather a conservative limit to support safe long-term exposure. Calcium hydroxide’s acceptance in food additive tables underlines that current use practices align with safety evaluations without requiring a specific numeric ADI in widely accessible regulatory summaries.

Comparison With Similar Additives

Calcium hydroxide can be compared with other alkaline additives used for pH control, firming, or processing functions in foods. For example, sodium bicarbonate also acts as a pH control agent and leavening component in certain formulations, and it differs in solubility and buffering capacity compared to calcium hydroxide. Calcium chloride is another firming agent that contributes calcium ions to formulations and interacts with pectin in produce to enhance firmness, but it does not significantly alter pH in the same way as an alkaline compound such as calcium hydroxide. Each additive’s functional profile and compatibility with other ingredients define its typical use cases, and formulators choose among them based on desired outcomes such as texture, pH adjustment, or mineral fortification. Unlike these other additives, calcium hydroxide’s primary role in certain traditional processes, such as nixtamalization, highlights specific cultural and technological applications where its alkaline properties are essential. Such comparisons illustrate that the choice of additive depends on both functional requirements and formulation context rather than a single universal property.

Common Food Applications Narrative

Calcium hydroxide appears in a variety of food production contexts where its functional properties provide technological advantages. In vegetable and fruit processing, it helps maintain firmness during canning or thermal treatments, contributing to consumer-desirable textures. Traditional food processes such as the preparation of masa from maize for tortillas rely on alkaline treatment with calcium hydroxide to alter texture and improve dough handling. In sugar refining, calcium hydroxide participates in clarification and pH adjustment steps that support efficient processing and quality outcomes. The compound is also used in dairy product categories for acidity control and can be present in fortified beverages to contribute calcium. Across these broad settings, its use is guided by regulatory conditions that frame acceptable food applications under good manufacturing practice. Processors incorporate calcium hydroxide in formulations where pH control, firming action, or buffering capacity is needed, and these uses help deliver consistent quality across diverse food categories. While the specific foods vary widely, the underlying rationale for inclusion remains tied to achieving a defined technological effect without compromising product integrity. Users in product development and quality assurance consider calcium hydroxide’s functional behavior alongside formulation goals to integrate it effectively into suitable applications.

Safety & Regulations

FDA

  • Approved: True
  • Regulation: 21 CFR 184.1205

EFSA

  • Notes: Numeric ADI not confirmed in authoritative EFSA deep link
  • E Number: 526

JECFA

  • Notes: Numeric ADI not available in the d JECFA specifications
  • Ins Number: 526

Sources

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