Calcium Ascorbate

Calcium ascorbate is the calcium salt of L-ascorbic acid and is traded as the dihydrate, CAS 5743-28-2 (the anhydrous compound carries CAS 5743-27-1), molecular formula C12H14CaO12·2H2O, molecular weight 426.34. The powder is white to slightly yellowish and crystalline, dissolves in water at roughly 50 g per 100 mL, and is practically insoluble in ethanol. Unlike sodium ascorbate it contributes no sodium to the formulation; instead it delivers two nutrients from one raw material, approximately 9.4 percent elemental calcium on the dihydrate (about 10.3 percent calculated on the anhydrous salt) alongside an ascorbic acid equivalent of approximately 82.6 percent. Both figures are theoretical values from the formula and should be used directly when setting label claims and overages, since the vitamin C loading per kilogram is meaningfully lower than that of the free acid or the sodium salt. The salt is compendial across the major pharmacopoeias. USP sets assay at 98.0 to 101.0 percent of C12H14CaO12·2H2O on the as-is basis, BP and Ph. Eur. tighten this to 99.0 to 100.5 percent, and FCC food grade requires not less than 98.0 percent. Specific rotation runs +95 to +97 degrees, a 10 percent w/v solution reads pH 6.8 to 7.4, and loss on drying is limited to 0.1 percent, so the material is comparatively dry and well suited to moisture-sensitive dry blends. Purity controls include fluoride not more than 10 ppm, arsenic not more than 3 micrograms per gram under USP, lead not more than 2 mg/kg under FCC, and iron and copper limits of 2 and 5 ppm respectively under Ph. Eur. Each lot is despatched with a batch certificate of analysis, and elemental impurity and microbiological testing can be extended to a buyer's own protocol. Because its solution sits close to neutral, calcium ascorbate is the usual choice for chewable and effervescent tablets, powder sticks and beverage bases where the sharpness of ascorbic acid is unwanted, and for combination calcium and vitamin C products where a single ingredient simplifies the blend. Vitamin C has an established role in collagen formation and normal antioxidant defence, and calcium is an established structural mineral nutrient; both functions are declared on that basis only. In food processing the additive is cleared as E302 / INS 302 and is applied as an antioxidant, including anti-browning treatment of fresh-cut fruit and vegetables. Thovek supplies the material ex-India in bulk export packing with documentation prepared for the destination market.