Slow lactate gluconate exchange in calcium complexes during precipitation from supersaturated aqueous solutions. (November 2020)

• Record Type: Journal Article
• Authors: Garcia, André C.; Hansen, Jesper S.; Bailey, Nicholas; Skibsted, Leif H.
• Is Part Of: Food research international. Volume 137(2020)
• Publication Date: 2020-11
• Subjects: Supersaturation -- Calcium hydroxycarboxylates -- Kinetic modelling; Food -- Analysis -- Periodicals; Food industry and trade -- Periodicals; Food industry and trade -- Canada -- Periodicals; Food Technology -- Periodicals; Food -- Periodicals; Food-Processing Industry -- Periodicals; Aliments -- Industrie et commerce -- Périodiques; Aliments -- Industrie et commerce -- Canada -- Périodiques; Aliments -- Recherche -- Périodiques; Food industry and trade; Canada; Periodicals; Electronic journals; 664.005
• DOI: 10.1016/j.foodres.2020.109539
• Languages: English
• ISSNs: 0963-9969

Abstract

Graphical abstract: Highlights: Sodium gluconate dissolves calcium lactate resulting in strong supersaturation. Spontaneous supersaturation is accommodated in a general kinetic model. Modelling identifies slow ligand exchange as crucial for supersaturation robustness. Abstract: Saturated solutions of calcium l -lactate in water or in deuterium oxide continuously dissolve calcium l -lactate by addition of solid sodium d -gluconate and become strongly supersaturated in calcium d -gluconate due to no or slow precipitation. The quantification of total dissolved calcium allied with the calcium complexes equilibrium constants allowed an ion speciation, which shows an initial non-thermal and spontaneous supersaturation of more than a factor of 50 at 25 °C only slowly decreasing after initiation of precipitation of calcium d -gluconate after a lag phase of several hours. A mathematical model is proposed, based on numerical solution of coupled differential equations of dynamics of l -lactate and d -gluconate exchange during the lag phase for precipitation and during precipitation. A slow exchange of l -lactate coordinated to calcium with d -gluconate is indicated with a time constant of 0.20 h −1 in water and of 0.15 h −1 in deuterium oxide and a kinetic deuterium/hydrogen isotope effect of 1.25. Such spontaneous non-thermal supersaturation and slow ligand exchange with a pseudo first order equilibration process with a half-life of 3.5 h in water for calcium hydroxycarboxylates can help to understand the higher calcium bioavailability from calcium hydroxycarboxylates compared to simple salts.