Distribution of Milk Clotting Enzymes Between Curd and Whey and Their Survival During Cheddar Cheese Making

Abstract

A linear diffusion test capable of measuring milk clotting enzyme activity at concentrations of 1 x 10 -4 to 1 x 10 -l rennin units per ml is described.The distribution of rennet activity between curd and whey in freshly coagulated milk was measured at 72% in the whey and 31% in the curd at pH 6.6.At pH 5.2, the whey contained 17% and the curd 86%.Total recovery of activity was 102 -+ 5%.Distribution of milk clotting enzymes from Mucor pusillus var.Lindt and Mucor miebei between curd and whey in freshly coagulated milk was independent of pH with approximately 83% in the whey and 17% in the curd.Porcine pepsin was unstable, precluding accurate assessment of enzyme distribution.During the manufacture of Cheddar cheese approximately 35% of the rennet activity was destroyed up to the time the whey was drained, and 6% remained in the cheese following pressing.Neither of the microbial enzymes lost activity during cheese making.Most of the activity remained in the whey while only 2 to 3% was detected in the cheese after pressing. I NT RODUCTI ONUsual procedures (3, 8) for measuring the activity of milk clotting enzymes are satisfactory for evaluating concentrated solutions such as commercial rennet extract but inadequate for the low enzyme concentrations in