Effects of Ca(II) ions on Cu(II) ion-phytic acid interactions.
In vitro interactions among phytic acid (PA), Cu(II) ions, and Ca(II) ions were examined as functions of PA:Cu(II):Ca(II) molar ratios and pH. Ca(II) ions competed with Cu(II) ions for binding by the soluble phytate species for PA:Cu(II) molar ratios ranging from 10:1 to 1:6 and pH values in the 2.4-5.9 range. At pH values where precipitation occurred, Ca(II) ions potentiated Cu(II) ion binding by the precipitated phytate species for PA:Cu(II) molar ratios of 10:1 to 1:3. At lower PA:Cu(II) molar ratios, Ca(II) ions competed with Cu(II) ions for binding by the precipitated phytate species. Compositions of the precipitated copper-calcium phytates are reported.
Southern Regional Research Center, U.S. Department of Agriculture, New Orleans, LA 70179.
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D002118:Calcium; D003300:Copper; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010833:Phytic Acid
D003300:Copper; D010833:Phytic Acid; D002118:Calcium