Hydroxycarboxylate combinations for increasing solubility and robustness of supersaturated solutions of whey mineral residues

Calcium phosphates present in whey mineral residue is a potential source of calcium for dietary purposes. Combinations of aqueous isocitrate and citrate were found more efficient than each of the isomers in dissolving dried insoluble whey processing mineral residues spontaneously forming supersaturated solutions. Hydrogen isocitrate was found around 30% less efficient in these non thermal dissolution processes compared to hydrogen citrate based on amount of dissolved calcium. In contrast, the lag phase of up to 4 h for precipitation of calcium citrate from the supersaturated solutions was significantly longer when calcium isocitrate was present. Highest degree of supersaturation with longest lag phase for precipitation was found for citrate/isocitrate combinations in a 1:1 ratio. Addition of calcium saccharate during dissolution further prolonged the lag phase simultaneously preserving the higher supersaturation degrees. Combinations of the three hydroxycarboxylates seem accordingly to provide a basis for increasing calcium availability from dried whey mineral fractions consisting mainly of calcium hydrogen phosphate and hydroxyapatite of low solubility with the perspective of transforming a side stream from cheese production into valuable functional foods.