Aqueous Solubility of Calcium l-Lactate, Calcium d-Gluconate, and Calcium d-Lactobionate: Importance of Complex Formation for Solubility Increase by Hydroxycarboxylate Mixtures

Abstract

Among the calcium hydroxycarboxylates important for cheese quality, D-lactobionate [Ksp = (7.0 ± 0.3) × 10(-3) mol(3) L(-3)] and L-lactate [Ksp = (5.8 ± 0.2) × 10(-3) mol(3) L(-3)] were found more soluble than D-gluconate [Ksp = (7.1 ± 0.2) × 10(-4) mol(3) L(-3)], as indicated by the solubility products determined electrochemically for aqueous 1.0 M NaCl at 25.0 °C. Still, solubility of calcium L-lactate increases by 45% in the presence of 0.50 M sodium D-gluconate and by 37% in the presence of 0.50 M sodium D-lactobionate, while solubility of calcium D-gluconate increases by 66 and 85% in the presence of 0.50 M sodium L-lactate and 0.50 M sodium D-lactobionate, respectively, as determined by complexometric titration. Sodium L-lactate and sodium D-gluconate have only little influence on solubility of calcium D-lactobionate. The increased solubility is described quantitatively by calcium binding to D-gluconate (K1 = 14 ± 3 mol(-1) L) in 1.0 M NaCl at 25 °C, D-lactobionate (K1 = 11 ± 2 mol(-1) L), and L-lactate (K1 = 8 ± 2 mol(-1) L), as indicated by the association constants determined electrochemically. In mixed hydroxycarboxylate solutions, calcium binding is quantitatively described by the geometric mean of the individual association constants for both aqueous 1.0 and 0.20 M NaCl, indicating a 1:1 stoichiometry for complex formation.

Impact of freeze-thaw treatment on the stability of calcium-fortified soy beverages

“…Calcium chloride (CaCl 2 ) is highly dissociated while calcium lactate (CaL 2 ) is only partially dissociated as a consequence of the following two step dissociation equilibrium (Vavrusova, Munk, & Skibsted, 2013):…”

“…Nevertheless, the crioprotective effect was reported for highly dissociated sodium lactate. According to Vavrusova et al (2013), an important proportion of lactate ion is associated to binary CaL þ complex (Eqs.…”

Calcium‐buffering effects of gluconate and nucleotides, as determined by a novel fluorimetric titration method

“…Note the clear shifts along the x-axis between the three curves. values of 32.3 and 71.4 mM from calcium electrode-based measurements and iodometric titrations in 0.2 M NaCl, respectively (Vavrusova et al 2013). Likewise, the increase in K 0.5 by 13.85 μM for the iKCl solution with 3.3 mM free nucleotides indicates a K D for Ca 2+ binding to ATP 2− of 0.24 mM, which is very close to the 0.2 mM reported by Schoenmakers et al (1992).…”

Yolk‐Shell Porous Microspheres of Calcium Phosphate Prepared by Using Calcium L‐Lactate and Adenosine 5′‐Triphosphate Disodium Salt: Application in Protein/Drug Delivery

“…ATP, the common energy carrier of cells in biology, is used as a biocompatible organic phosphorus source for the synthesis of calcium phosphate‐nanostructured materials and an effective stabilizer for amorphous calcium phosphate in aqueous solution 5. 29–31 Calcium lactate, a common addictive in food32 and a biocompatible component in biology,33, 34 can be used as a promising calcium source. The effects of the concentration of CL and microwave hydrothermal temperature and time on the morphology and crystal phase of the product were investigated.…”