Rheological Behavior of Casein Micelles and Reconstituted Skim Milk Gels: The Effect of Temperature on Gelation Induced by Rennet

The temperature dependence of the gelation process for various rennet-casein micelle systems was investigated by analysis of gelation curves obtained from viscoelastic measurements under the conditions of a fixed weight ratio of rennet to casein micelle. The gelation rate for the casein micelle suspension decreased abruptly with decreasing temperature and the maximum modulus shows a maximum at 20 to 40°C. On the other hand, the gelation rate for reconstituted skim milk passed through a maximum between 30 and 40°C, and the maximum modulus decreases with increasing temperature. The gelation rate for reconstituted skim milk is much slower than that for the casein micelle solution at the corresponding temperature. These results were explained by assuming that the presence of lactose and β-lactoglobulin caused the reduction in the gelation rate for rennet-casein micelle systems.