The protective effect of skim milk up to 15 g L−1 for a peptidase from P. fluorescens against low temperature inactivation (30–70 °C) was also described by Schokker and Van Boekel, 1998 and Schokker and Van Boekel, 1999a. Regarding high temperature inactivation (80–120 °C), no protective effect of protein was observed by Schokker and Van Boekel (1999b). An increasing inactivation rate is described in the presence of 1.8% (w/v) caseinate, perhaps caught by the aggregation of enzyme molecules with caseinate