Rennet induced gelation of reconstituted milk protein concentrates: The role of calcium and soluble proteins during reconstitution

The gelation behaviour of reconstituted milk protein concentrate (MPC) was studied with or without addition of calcium, by direct addition or by slow equilibration using dialysis against milk. The presence of calcium was critical in the formation of a rennet gel, and it also caused precipitation of the soluble caseins formed during hydration of the MPC samples. The preceding stages of gelation were followed using diffusing wave spectroscopy and differences in the network formation were measured by rheology. The results indicate that gelation properties of reconstituted MPC are strongly affected, not only by the amount of soluble calcium, but also by the soluble caseins present.