Continuous Production of Cheese by Immobilized Milk‐Clotting Protease from Aspergillus niger MC4

Milk clotting protease from Aspergillus niger MC4 immobilized on glycidyl methacrylate−pentaerythritol triacrylate copolymer GP4 was used for continuous production of cheese using a packed bed reactor. Factors affecting the hydrolysis of κ‐casein and clot formation were studied. Acidified milk (pH 5.8) preincubated at 37 °C when passed through the column at a flow rate of 80 mL/min attained the required degree of hydrolysis of κ‐casein for the coagulation in a single pass. Fortification of the hydrolyzed milk with CaCl 2 and FeCl 3 to a final concentration of 0.01 and 0.02 M, respectively, and incubation of fortified milk at 60 °C for 2 h resulted in a hard cake of cheese. The yield of raw cheese was 28 g/100 mL of milk. The immobilized milk‐clotting protease was used for 60 days (8 h/day) without any loss in productivity.