Gelation of Milk Solids by Orthophosphate

Abstract

The gelation of milk solids dispersed in high concentrations of orthophosphate was studied by following changes in viscosity of the solutions. The rate of the gelation process was found dependent on the concentration of phosphate, calcium, and caseinate complex. Also, the rate depends on pH, temperature, agitation, and the identity of the phosphate counterion. Below certain critical concentrations, polyphosphates retard gelation. Metal ions also retard gelation but have no critical concentration limits. Viscosity data indicate that the gelation process consists of two phases: An initial, null phase characterized by little change in the viscosity and a second phase characterized by a rapid change in the viscosity. Although a high concentration of phosphate provides the driving force for the gelation process, calcium is also required. During gelation CaHPO4 may possibly be bound at sites in the interior of the caseinate particles. © 1965, American Dairy Science Association. All rights reserved.