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.