Complexing of Calcium by Hexametaphosphate, Oxalate, Citrate, and Ethylenediamine-Tetraacetate in Milk. II. Dialysis of Milk Containing Complexing Agents

Abstract

The influence of hexametaphosphate (HMP), oxalate, citrate, and ethyl-enediamine-tetraacetate (EDTA) on salt equilibria in milk was studied by continuous and equilibrium dialyses of milk containing up to 30 mm of these agents. Alteration of milk was determined by the rate of diffusion of calcium and phosphorus from milks containing various concentrations of the agents. Added sodium citrate dissolved a portion of the calcium and all of the inorganic phosphate. Oxalate and EDTA made diffusible all of the calcium in milk. HMP was unique in that phosphorus and calcium were less diffusible with small amounts of HMP. Excessive additions induced decomposition of the colloidal inorganic salts similar to that which occurred from citrate. Certain amounts of HMP still remained in the nondiffusible phase after dialysis, indicating that it combined with the casein complex. © 1965, American Dairy Science Association. All rights reserved.