Influence of pH on Protein Interactions and Microstructure of Process Cheese

Abstract

During the manufacture of process cheese, biochemical characteristics (casein solubilization, peptization coefficient, and water-holding capacity) were investigated using a combination of microscopic and rheological techniques in order to understand the influence of pH. The contribution of ionic interactions to the stabilization of this structure was also studied. Relationships were observed between pH variation and the characteristics of process cheese that demonstrated the importance of pH control during the manufacturing process. Optimal pH conditions during manufacture ranged from 5.7 to 6.0. Small changes in ionic composition and strength modified the protein interactions substantially and had important repercussions on the final structure and quality of the protein gel that was established during processing of cheese. In addition to ionic interactions, hydrogen and hydrophobic interactions appeared to be important in the structural stabilization of process cheese.