Dynamical mechanical characterization of gelling micellar casein particles

Micellar casein particles (submicelles) were formed by removing calcium from native casein through chelation with sodium polyphosphate. The submicelles aggregated with time and eventually formed a gel if the casein concentration is sufficiently high. The frequency dependent shear modulus was measured during the gelation process as a function of temperature, concentration, and pH. Gelation occurred via a percolation process at all conditions, but increasing the temperature or the concentration accelerated the process. The concentration (C) and temperature (T) dependence of the gel time (t(g)) were independent and could be described by a simple expression valid over a wide range of C and T. The shear modulus of the gels increased with C-2, while varying the temperature had only a very weak effect. (c) 2007 The Society of Rheology.