Calcium D-saccharate: aqueous solubility, complex formation, and stabilization of supersaturation
Research output: Contribution to journal › Journal article › Research › peer-review
Molar conductivity of saturated aqueous solutions of calcium d-saccharate, used as a stabilizer of beverages fortified with calcium d-gluconate, increases strongly upon dilution, indicating complex formation between calcium and d-saccharate ions, for which, at 25 °C, Kassoc = 1032 ± 80, ΔHassoc° = -34 ± 6 kJ mol-1, and ΔSassoc° = -55 ± 9 J mol-1 K-1, were determined electrochemically. Calcium d-saccharate is sparingly soluble, with a solubility product, Ksp, of (6.17 ± 0.32) × 10-7 at 25 °C, only moderately increasing with the temperature: ΔHsol° = 48 ± 2 kJ mol-1, and ΔSassoc° = 42 ± 7 J mol-1 K-1. Equilibria in supersaturated solutions of calcium d-saccharate seem only to adjust slowly, as seen from calcium activity measurements in calcium d-saccharate solutions made supersaturated by cooling. Solutions formed by isothermal dissolution of calcium d-gluconate in aqueous potassium d-saccharate becomes spontaneously supersaturated with both d-gluconate and d-saccharate calcium salts, from which only calcium d-saccharate slowly precipitates. Calcium d-saccharate is suggested to act as a stabilizer of supersaturated solutions of other calcium hydroxycarboxylates with endothermic complex formation through a heat-induced shift in calcium complex distribution with slow equilibration upon cooling.
Original language | English |
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Journal | Journal of Agricultural and Food Chemistry |
Volume | 64 |
Issue number | 11 |
Pages (from-to) | 2352-2360 |
Number of pages | 9 |
ISSN | 0021-8561 |
DOIs | |
Publication status | Published - 2016 |
- calcium complexes, calcium d -gluconate, calcium d -saccharate, calcium salt solubility, spontaneous supersaturation
Research areas
ID: 160668107