Adult bovine rennet (ABR), rennet produced by Aspergillus niger var. awamori fermentation (RPF) and calf rennet (CR) were tested for their effect on proteolysis during ripening of Brazilian Prate cheese (Dutch type). Cheeses were brined for 3 and 6 h (16 degrees Be) and ripened for 6 and 66 d (12 degrees C and 90% relative moisture). Protein degradation was followed by polyacrylamide gel electrophoresis in the presence of 7M urea. Proteolysis was evident for all protein fractions, alpha(s1)-casein (CN) was readily (at 6(th) day) degraded to alpha(s1)I-CN in all treatments. Degradation was increased along the ripening period. ABR was more proteolytic than CR and RPF. beta-CN was slightly degraded to beta I-CN in all treatments, and no differences were detected among rennet types. Salt concentrations achieved in the cheeses showed no influence on the proteolytic process.526318322