title: Effects of solvent and alkaline earth metals on the heat-induced precipitation process of sodium caseinate.
abstract: The precipitation temperatures of sodium caseinate in H(2)O and D(2)O in the presence of Mg(2+), Ca(2+), Sr(2+) and Ba(2+) were investigated through fluorescence, turbidity and conductivity experiments. As for the ability of the divalent cations (1-17.5mM) to induce the precipitation process in H(2)O, the sequence Ba(2+) ≥ Ca(2+)>Mg(2+)>Sr(2+) was found. Remarkably, while at low salt concentrations (<10mM) precipitation temperatures (T(Ps)) were found to change significantly depending on the specific cation, at higher concentrations (>10mM) the differences among the different cations were greatly reduced. By fitting these results with a modified Jones-Dole equation, we confirmed that the less hydrated ions possess a greater capacity to induce precipitation. In D(2)O, the order of ion ability to induce caseinate precipitation was Ba(2+)>Ca(2+)>Sr(2+)>Mg(2+). The different hydrophobicity between D(2)O and H(2)O was shown to affect significantly the T(Ps) of caseinate in the presence of calcium, strontium and barium.
authors.affiliation: Dipartimento di Agricoltura, University of Molise, Campobasso, Italy. lopez@unimol.it
authors.forename: Francesco
authors.initials: F
authors.lastname: Lopez
authors.forename: Francesca
authors.initials: F
authors.lastname: Cuomo
authors.forename: Pierandrea Lo
authors.initials: PL
authors.lastname: Nostro
authors.forename: Andrea
authors.initials: A
authors.lastname: Ceglie
mesh_terms: D002364:Caseins / Q000737:chemistry*; D011232:Chemical Precipitation; D006358:Hot Temperature; D007700:Kinetics; D008673:Metals, Alkaline Earth / Q000737:chemistry*; D011485:Protein Binding; D012997:Solvents / Q000737:chemistry
chemical_list: D002364:Caseins; D008673:Metals, Alkaline Earth; D012997:Solvents