High-pressure processing of orange juice: Kinetics of pectinmethylesterase inactivation

A kinetic study of pectinmethylesterase (PME) inactivation in orange juice was conducted. Juice samples were subjected to combinations of high pressure (400, 500, 600 MPa) and thermal (25, 37.5, 50 degreesC) treatments for various time periods. PME inactivation followed a first-order kinetic model with a residual activity of pressure-resistant enzyme remaining. Calculated D-values ranged from 4.6 min to 117.5 min at 600 MPa/50 degreesC and 400 MPa/25 degreesC, respectively. Pressures in excess of 500 MPa resulted in sufficiently fast inactivation rates for economic viability of the process.