Rheological investigations of alkaline-induced gelation of skimmed milk and reconstituted skimmed milk concentrates

The gelation of milk and of reconstituted milk at various concentrations of solids, as induced by alkaline pH, has been investigated using dynamic rheological methods. The gels formed at pH 12 were relatively weak and exhibited an exponential relationship between the elastic modulus G′ and the protein concentration φ (G′∼φ3.9). Gelation time decreased with both increasing temperature and protein concentration. Chromatographic analysis of the proteins showed that storage at pH 12 resulted in changes in their chemical structure.