Characterization and comparative study of animal rennets from different ruminants applied to goat milk

The characterization of rennets of different origin (calf, lamb and kid goa t) was studied in goat milk in terms of their enzymatic and coagulant activ ity as well as the cheese yield. The determination of enzyme activity according to a modified IDF Norm 110:1 997 led to the conclusion that the application of ionic strength gradients between 0.3-0.6 N in NaCl implies a complete separation of the enzymes and a greater reproducibility of the method. From a comparative study of rennet with the same enzymatic activity but from different sources with the appli cation of IDF Norm 157:1992, we can deduce a higher coagulant activity in c alf rennet followed by lamb. The lowest activity corresponded to kid goat r ennet. A comparative study of cheese yield was carried out in goats milk using ren nets with similar enzymatic activity but different origin. Three batches of fresh cheese were produced at 2 levels, one in the pilot plant and another in the laboratory. In the laboratory the highest yield found was in calf r ennet with 90% activity due to chymosin. However, in the pilot plant the hi ghest cheese yield corresponded to lamb rennet, followed by calf and finall y the kid goat rennet. These results confirm that higher coagulant and enzy matic activity is not always associated with higher yield.