Evaluation of Thiol Activated Proteases from Clam Viscera as a Rennet Substitute for Cheese-Making

Clam rennet, which is a crude enzyme preparation of cathepsin B-like protease from clam viscera was characterized and compared to porcine pepsin and calf rennet for its suitability as a milk coagulant in cheesemaking. Clam rennet was more proteolytic and produced a softer curd than the other two coagulants. However, influences of the pH and temperature on milk clotting with clam rennet were very similar to those of calf rennet. The cheddar cheese made from clam rennet was not inferior to the Cheddar cheese made from calf rennet. Quality enhancement occurred despite the view that high ratio of proteolytic to clotting activity is generally considered to be unfavorable for cheese-making. The higher proteolytic activity appeared to accelerate the ripening process. A small yield loss occurred as a result of excessive proteolysis during cheese-making.