Proteolysis during ripening of soft cheese I - Method to manufacture rennet-free experimental cheese

In the present paper a new method and equipment to obtain rennet-free experimental cheese are presented and tested. The methodology was based in the inactivation of the coagulant enzyme after κ-casein hydrolysis and before curd formation. Control and rennet free cheeses were manufactured and analysed to determine chemical composition and advance of proteolysis. Milk-clotting activity was tested in whey aliquots provided by experimental and control manufactures. The coagulant enzyme was completely inactivated in the established conditions for rennet-cheese, and it remained active in control cheeses. All cheeses showed similar values of pH, moisture content, total protein content and sodium chloride concentration. Control cheeses experimented extensive proteolysis during ripening, which was assessed by an important increase in the soluble nitrogen. For rennet-free cheeses, soluble nitrogen did not increase significantly during the same period. The studied methodology demonstrated to be useful and appropriate to the study of cheese proteolysis.