Solubility of Tricalcium Citrate in Solutions of Variable Ionic Strength and in Milk Ultrafiltrates

Abstract

Solubility of tricalcium citrate has been determined at 21 and 95° C. by dissolution in water and by precipitation from supersaturated solutions containing various proportions of calcium to citrate and at pH 4.4 to 8.8. Solubility product in solutions at equilibrium varied with ionic strength, according to the relation pks=17.63−10.84 μ, but was unaffected by variations in pH and temperature and by the presence of magnesium or phosphate ions. Milk ultrafiltrates were shown to be saturated with tricalcium citrate, i.e., the calculated pks values agreed with the solubility product in all but two of the 15 samples tested, and composition of two ultrafiltrates was unaffected by agitation with crystals of tricalcium citrate. © 1960, American Dairy Science Association. All rights reserved.