This process permits recovery of caseins and whey proteins in a single step. The basic principle is that whey proteins which are normally acid stable, become sensitive to acid coagulation after heat treatment. This principle is exploited in the manufacture of ricotta cheese, Paneer and Channa, and in the manufacture of "co-precipitated" milk protein concentrates. The basic process for heat-acid coagulation is:
- Heat milk or milk-whey blends to at least 80C for at least five minutes to completely denature (unfold) the whey proteins and encourage association of whey proteins with casein micelles.
- Continue heating and acidify slowly with gentle agitation. The caseins and whey proteins will coagulate together and form either sinking or floating curds.