ALUMINUM SODIUM SULFATE

CAS: 7784-28-3 FIRMING AGENT, LEAVENING AGENT, PH CONTROL AGENT

Aluminum sodium sulfate with CAS 7784-28-3 is an inorganic salt used in food technology for its firming, leavening, and pH control functions. In the United States it appears in FDA inventories for indirect and multiple purpose additives.

What It Is

Aluminum sodium sulfate, identified by CAS number 7784-28-3, is an inorganic crystalline compound belonging to the family of sulfate salts. It is known in technical use as a firming agent, leavening agent, and pH control agent. In food technology, compounds like aluminum sodium sulfate are included among substances that can influence the physical properties of food, such as texture and acidity, and are used in formulations where controlled chemical reactions are needed. While aluminum sodium sulfate can be described through various synonyms, all refer to the same basic chemical entity composed of aluminum, sodium, sulfur, and oxygen in a defined ratio. Regulatory inventories list this compound under several provisions of Title 21 of the Code of Federal Regulations, indicating that it is recognized in some food-additive contexts, including both direct food additives and substances that contact food under specified conditions, with functions tied to its chemical properties of buffering and reactivity. The presence of this compound in regulatory lists reflects historical decisions on its functional utility rather than detailed risk evaluations of modern dietary exposures.

How It Is Made

The manufacture of aluminum sodium sulfate typically involves controlled chemical reactions between aqueous solutions of aluminum sulfate and sodium sulfate under conditions that facilitate crystal formation. In industrial settings, these reactants are combined and allowed to crystallize, often yielding a hydrated solid known as the dodecahydrate form. The process is designed to produce high-purity material that meets specifications suitable for its intended use. Raw material quality, water purity, and process controls such as temperature and pH adjustments play important roles in determining the final product quality. After crystallization, the compound is filtered, washed, and dried to a stable form for distribution. For food-related uses, additional quality assurance steps ensure that the product meets applicable chemical purity criteria, though specific food-grade specifications are defined by regulatory authorities or pharmacopeial standards when referenced. Producers supply this compound as a white crystalline powder that dissolves readily in water, reflecting its sulfate salt character. The manufacturing process and resulting solid form are consistent with other alum family compounds, which are known for their utility in modifying physical properties in both food and industrial applications.

Why It Is Used In Food

In food systems, aluminum sodium sulfate is used because of its ability to influence texture, gas release, and acidity. As a firming agent, it can help maintain cell structure in fruits and vegetables subjected to processing, making them retain a desired crispness. In leavening systems, compounds like aluminum sodium sulfate participate in acid-base reactions that generate carbon dioxide when combined with alkali components such as sodium bicarbonate. This gas release contributes to the rising of baked goods. It also can serve as a pH control agent, moderating acidity in formulations where stable pH contributes to product consistency or sensory attributes. The choice to use this compound in a formulation depends on its compatibility with other ingredients and the technological outcome desired by the formulator. For example, in a buffered leavening system, the controlled release of carbon dioxide can influence crumb structure and volume in baked products. As a pH control agent, it helps adjust the balance between acidity and alkalinity, which can affect enzyme activity, color development, and microbial stability in food products. The multifunctional nature of the compound makes it attractive where multiple technological effects are needed from a single additive.

Adi Example Calculation

Because a specific numeric acceptable daily intake (ADI) was not allocated in historical evaluations for aluminum sodium sulfate by expert committees, it is not possible to provide a precise illustrative calculation using a numeric ADI value. Typically, if an ADI were established, an example calculation might involve taking that ADI and multiplying it by a hypothetical body weight to estimate a daily amount that could be consumed without appreciable risk. For instance, with a numerical ADI, one would compute the product of the ADI value in milligrams per kilogram of body weight and a representative body weight, such as for an adult or child, to illustrate how much of the additive could be present in the diet. In the absence of a specific numeric ADI for this compound, such calculations cannot be reliably performed, and the focus remains on understanding that regulators have evaluated the compound and determined the contexts in which it may be used based on available data.

Safety And Health Research

Safety evaluations of aluminum-containing food additives like aluminum sodium sulfate consider both the chemical behavior of the compound and systemic exposure from dietary intake. Regulators and expert panels examine toxicological data, including studies on absorption, distribution, metabolism, and elimination, as well as any evidence related to genotoxicity or reproductive endpoints. For aluminum sodium sulfate and related alum compounds, historical assessments by expert committees have often concluded that available data do not warrant a specific acceptable daily intake, reflecting either low concern at typical exposure levels or insufficient evidence to allocate a numeric value. Research literature on aluminum exposure more broadly encompasses soluble aluminum compounds and considers cumulative intake from food, water, and other sources. While some studies in laboratory models explore potential effects at high doses, these findings are interpreted in light of relevant exposure levels in humans, and safety frameworks incorporate conservative safety factors to protect public health. Consumer exposure to aluminum sodium sulfate from formulated food products is expected to be low relative to background dietary aluminum from other sources. As with many food additives, ongoing research can inform risk assessments, and regulatory authorities may update evaluations as new data emerge, ensuring that safety considerations remain current.

Regulatory Status Worldwide

In the United States, aluminum sodium sulfate appears in official FDA inventories that document substances recognized for use in indirect food additive applications and multiple purpose food additives under sections of Title 21 of the Code of Federal Regulations. Specifically, the inventory lists this compound under 21 CFR 175.105 for resinous and polymeric coatings, 21 CFR 182.1131 for substances generally recognized as safe (GRAS) for specified uses, and 21 CFR 182.90 for substances migrating to food from paper and paperboard, reflecting the contexts in which the compound has historically been referenced by FDA records. These listings indicate that regulators have acknowledged the technical functions and potential uses of aluminum sodium sulfate, though specific usage conditions and limitations are defined in the d parts of the regulation. Internationally, the Joint FAO/WHO Expert Committee on Food Additives has evaluated aluminum sodium sulfate and related alum compounds, assigning an International Numbering System identifier and reviewing its functional class, but in historical evaluations a specific acceptable daily intake was not allocated. Regulatory frameworks outside the United States may classify this compound similarly based on its technical functionality and assessment of available safety data. The presence in multiple regulatory lists underscores recognition of its role as a technological additive, while modern regulatory review may focus on updated safety and exposure information to refine conditions of use.

Taste And Functional Properties

Aluminum sodium sulfate itself has minimal taste when used at the low levels typical of food additive applications, and its primary impact on sensory attributes stems from its functional behavior rather than direct flavor. As a salt of a strong acid and a weak base, it dissolves in water to yield ions that interact with other components in food. In applications like leavening, the rate at which it releases gas in the presence of moisture and alkali influences texture and volume rather than taste. Its buffering capacity means it can help maintain pH within a narrow range during processing, which in turn affects flavor perception indirectly by stabilizing acid-sensitive flavor compounds. Solubility in water allows it to disperse uniformly in aqueous food systems, but the compound is generally not used for its organoleptic properties. Instead, formulators rely on its chemical functionality to achieve consistent texture, structure, and acidity control. Because of its role in chemical reactions rather than as a flavoring agent, any residual metallic or bitter notes are typically negligible at the concentrations used in permitted food applications. Overall, the taste impact is secondary to functional contributions, and its sensory neutrality is one reason it can be incorporated without altering the intended flavor profile of the finished product.

Acceptable Daily Intake Explained

An acceptable daily intake (ADI) is a scientific estimate of the amount of a substance that can be consumed daily over a lifetime without appreciable health risk, based on available toxicological data and interpreted by regulatory authorities. For aluminum sodium sulfate, historical expert evaluations did not allocate a specific numeric ADI value, meaning that regulators did not identify a quantifiable limit based on the evidence available during those reviews. The absence of a numeric ADI does not imply unrestricted use but rather reflects the context of the evaluation, including considerations of typical exposure levels and the quality of safety data. When an ADI is established for a food additive, it often incorporates uncertainty factors to account for differences between test animals and humans and variability within human populations. Understanding ADIs helps consumers and professionals interpret regulatory decisions and the basis for permitted uses of additives. In the case of aluminum-containing compounds, total dietary exposure from all sources is considered in safety assessments, and regulators monitor emerging science to determine whether updates to guidance or limits are needed.

Comparison With Similar Additives

Aluminum sodium sulfate shares technological roles with other additives that influence pH, texture, or gas release in food systems. For example, sodium aluminum phosphate is another aluminum-containing leavening agent used in baked goods to react with bicarbonates and release carbon dioxide, though its reactivity profile and solubility differ, leading to variations in how it is formulated in mixes. Calcium sulfate functions as a firming agent in canned vegetables, where the divalent calcium ion strengthens cell walls, contrasting with the buffering and acidity-modulating actions of aluminum sodium sulfate. Citric acid, a common acidity regulator, adjusts pH through its organic acid character and imparts a sour taste at higher levels, whereas aluminum sodium sulfate affects pH with minimal direct flavor impact. Comparing these additives highlights that formulators choose specific compounds based on the desired balance of functional effects, solubility, and interaction with other ingredients, and that each additive has its own regulatory considerations and usage guidelines based on safety and technological need.

Common Food Applications Narrative

Aluminum sodium sulfate finds application in selected processed foods where texture, volume, and acidity control are part of the product design. In the context of baked goods, such as certain types of quick breads and cakes, it can be included in leavening blends that react with bicarbonates to produce carbon dioxide, contributing to desirable crumb structure. The controlled release of gas supports consistent rise and texture in mixes that are formulated for home baking or commercial production. Processed vegetable products, such as pickled cucumbers or relishes, sometimes benefit from the firming function of aluminum sodium sulfate, helping retain a crisp texture after heat treatment or storage. In food systems where pH adjustment is critical, such as batters or emulsified products, the buffering action assists in stabilizing conditions that affect protein functionality and microbial stability. While not universally used across all categories, this compound serves specific technological needs in formulations where multifunctional performance is sought. In each application, the inclusion level is determined by regulatory allowances and functional requirements, and formulators consider alternatives as well when optimizing product characteristics. The presence of aluminum sodium sulfate in ingredient lists reflects these targeted uses rather than broad ubiquity across all processed foods.

Safety & Regulations

FDA

  • Notes: Listed in FDA food additive and indirect additive inventories under specified CFR sections but not explicitly approved with stated conditions of use in the d inventory pages

EFSA

  • Notes: No specific EFSA evaluation deep link found for this exact compound

JECFA

  • Notes: Historical JECFA evaluations did not allocate a numeric ADI for aluminum sodium sulfate
  • Ins Number: 521

Sources

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