Effects of combined instantaneous high-pressure and medium temperature on peroxidase activity in wax gourd juices

摘要

Based on the instantaneous pressurization and depressurization produced by high-pressure single pole-cylinder pump and valve, the effects of the continuous processing on the peroxidase (POD) activity in wax gourd juices were investigated. Results showed that the processing factors such as pressure, temperature, pH and processing time are important to the POD activity. POD in crude juices could be inactivated apparently above 50 MPaCpH 4. 6, 35 deg C , 4 min), and activated at 20 MPa CP< 0.01). Itsremarkable inactivation could also be observed at 45 and 55 deg C (20 MPa, pH 4. 6, 4 min) , and the evident activation appears at the material temperature 35t (P< 0.01). The pH 3.0 could destroy POD almost completely (20 MPa, 35 deg C , 4 min), while pH6. 0 could not influence apparently the POD activity in crude juices(P> 0.05). In addition, the rules of POD activity along with the treatment time are variational under different processing pressures. The higher the treating pressure is, the shorter theprocessing time is needed to inactivate POD.