Food Grade Calcium Chloride

1.Properties and Characteristics Relevant to Food Use

• Chemical Formula:
  • CaCl₂ (also available as dihydrate CaCl₂·2H₂O or hexahydrate CaCl₂·6H₂O, though the dihydrate and anhydrous forms are common in food applications for their higher Ca concentration by weight).
• Appearance:
  • White, odorless, crystalline powder, granules, flakes, or pellets. Solutions are clear.
• Taste:
  • Salty. Can have a slightly bitter or metallic aftertaste at higher concentrations, which is why it's sometimes used in conjunction with NaCl or in applications where its functional properties are more critical than flavor contribution.
• Solubility:
  • Highly soluble in water and also soluble in ethanol. Dissolution is exothermic (releases heat), which can be a factor in how it's added to food preparations.
• Hygroscopicity:
  • Very hygroscopic and deliquescent (absorbs moisture from the air and can dissolve in it). This requires proper storage in airtight containers.
• pH:
  • Aqueous solutions are typically near neutral (pH 6-8), but can be slightly acidic.
• Purity: Food-grade CaCl₂ must meet stringent purity specifications, with limits on:
  • Heavy metals (e.g., lead, arsenic, mercury, cadmium)
  • Magnesium and alkali salts
  • Fluoride
  • Insoluble matter
  • Sulfates
  • Oxides and hydroxides

2.Production of Food-Grade Calcium Chloride

• Source Material Selection:
  • Starting materials (limestone, HCl, or crude CaCl₂ from Solvay process) must be of sufficient quality.
• Purification Steps:
  • Removal of Impurities: The crude CaCl₂ solution undergoes several purification stages. This may involve:
    • pH adjustment to precipitate heavy metal hydroxides and iron/aluminum.
    • Addition of reagents like barium chloride (if sulfates are an issue, though careful control is needed to avoid barium contamination) or activated carbon for color and odor removal.
    • Filtration and clarification to remove suspended solids.
  • Crystallization/Concentration: The purified solution is then concentrated by evaporation, and CaCl₂ is crystallized (often as dihydrate or anhydrous forms). Spray drying can be used to produce powders or granules.
• Quality Control:
  • Rigorous testing at various stages of production and for the final product is essential to ensure compliance with food-grade specifications. This includes analysis for heavy metals, arsenic, lead, and other potential contaminants.
• Packaging:
  • Packaged in food-grade materials that protect it from moisture and contamination.

3.Applications in Food and Beverages

3.1 Firming Agent

• Mechanism:
  • Calcium ions react with natural pectins (in fruits and vegetables) or alginates (added gelling agents) to form calcium pectate or calcium alginate. These are insoluble and create a more rigid structure, preventing the food item from becoming soft or mushy during processing (e.g., heating, canning, pickling).
• Examples:
  • Canned Fruits and Vegetables: Added to canned tomatoes, potatoes, carrots, apples, etc., to maintain firmness and texture.
  • Pickles: Helps keep pickles crisp.
  • Tofu Production: Used as a coagulant (nigari often contains MgCl₂, but CaCl₂ can also be used or be part of the coagulant mix) to precipitate soy protein from soy milk, forming the curd.
  • Low-Fat Cheese Analogues: Can help improve texture.

3.2 Calcium Fortification/Nutrient Supplement

• Mechanism:
  • Directly adds dietary calcium to foods and beverages.
• Examples:
  • Sports Drinks and Electrolyte Beverages: Replenishes calcium lost during exercise.
  • Bottled Water: Can be added to adjust mineral content and taste.
  • Soy Milk, Juices, and other Beverages: For calcium enrichment.
  • Dietary Supplements: As a source of calcium in tablet or capsule form (though other calcium salts like calcium carbonate or citrate are also common).

3.3 Brewing(Water Treatment)

• Mechanism: Adjusts the mineral content ("hardness") of brewing water. Calcium ions are important for:
  • Enzyme activity during mashing (alpha-amylase stability and activity).
  • Yeast health and flocculation.
  • pH reduction of the wort.
  • Clarification of the beer (helps precipitate proteins and oxalates).
• Effect:
  • Chloride ions (from CaCl₂) can enhance the perception of malt sweetness and fullness in beer, contrasting with sulfate ions which accentuate hop bitterness. Brewers often use a blend of calcium sulfate (gypsum) and calcium chloride to achieve desired water profiles.

3.4 Cheesemaking

• Mechanism:
  • Restores the calcium balance in pasteurized milk. Pasteurization can reduce the amount of soluble calcium, which is necessary for the enzyme rennet to effectively coagulate milk proteins (casein) and form a firm curd.
• Effect:
  • Leads to better curd formation, increased cheese yield, and improved texture.

3.5 Flavor Enhancer/ Salt Substitute Component

• Mechanism:
  • Imparts a salty taste. It can be used to reduce sodium content in some foods by partially replacing sodium chloride (NaCl).
• Considerations:
  • Has a different taste profile than NaCl (can be slightly bitter), so it's often used in blends or in applications where its other functional benefits are primary.

3.6 Anti-caking Agent (less common)

• Though highly hygroscopic, in some formulations it might be used in small amounts, or its hygroscopic nature might be leveraged in other ways in powdered mixes.

4.Regulatory Status and Safety

• Generally Recognized as Safe (GRAS):
  • In the U.S., calcium chloride is GRAS when used in accordance with good manufacturing practices.
• E Number:
  • E509 in Europe, where its use is authorized in various food categories with specific maximum levels in some cases.
• JECFA:
  • Has established an Acceptable Daily Intake (ADI) of "not specified," meaning that its use at levels necessary to achieve the desired technological effect is not considered a health concern.
• Labeling:
  • When used as a food additive, it must be declared in the ingredient list on food packaging, usually as "calcium chloride" or its E number.
• Safety Considerations:
  • While safe in the amounts typically used in food, concentrated solutions or anhydrous CaCl₂ can be irritating if ingested directly or if they come into contact with skin or eyes.
  • The exothermic reaction when dissolving in water means care should be taken when preparing solutions.
  • For individuals with specific health conditions (e.g., kidney problems, hypercalcemia), excessive intake of calcium from all sources (including fortified foods) should be monitored.

5.Quality Specifications for Food Grade

• Assay:
  • Minimum percentage of CaCl₂ (e.g., 93-100.5% for anhydrous, or specific ranges for dihydrate like 75.5-80.5% CaCl₂ which corresponds to 99-107% of CaCl₂·2H₂O).
• Heavy Metals:
  • Lead (Pb): Typically ≤ 1 or 2 mg/kg (ppm).
  • Arsenic (As): Typically ≤ 1 or 3 mg/kg (ppm).
  • Mercury (Hg): Very low limits, often ≤ 1 mg/kg.
  • Cadmium (Cd): Very low limits.
• Magnesium and Alkali Salts:
  • Limits on these impurities, as they can affect functionality or taste. Typically ≤ 5%.
• Fluoride:
  • Limits, e.g., ≤ 0.004% (40 ppm).
• Insoluble Matter:
  • Very low.
• Acidity or Alkalinity:
  • Must fall within a specified range.
• Clarity and Color of Solution:
  • A solution of specified concentration should be clear and colorless.

6.Handing and Storage of Food-Grade CaCl₂

• Hygroscopicity:
  • Due to its strong tendency to absorb moisture, food-grade calcium chloride must be stored in tightly sealed, airtight containers in a cool, dry place.
• Prevent Caking:
  • Proper storage helps prevent caking and maintain its free-flowing properties if in powder or granular form.
• Material Compatibility:
  • Use containers and utensils made of materials that are not corroded by calcium chloride (e.g., food-grade plastics, glass, some stainless steels).