Thermal and high pressure inactivation kinetics of blueberry peroxidase

This study for the first time investigated the stability and inactivation kinetics of blueberry peroxidase in model systems (McIlvaine buffer, pH = 3.6, the typical pH of blueberry juice) during thermal (40-80 degrees C) and combined high pressure-thermal processing (0.1-690 MPa, 30-90 degrees C). At 70-80 degrees C, the thermal inactivation kinetics was best described by a biphasic model with similar to 61% labile and similar to 39% stable fractions at temperature between 70 and 75 degrees C. High pressure inhibited the inactivation of the enzyme with no inactivation at pressures as high as 690 MPa and temperatures less than 50 degrees C. The inactivation kinetics of the enzyme at 60-70 degrees C, and pressures higher than 500 MPa was best described by a first order biphasic model with similar to 25% labile fraction and 75% stable fraction. The activation energy values at atmospheric pressure were 548.6 kJ/mol and 324.5 kJ/mol respectively for the stable and the labile fractions. Crown Copyright (C) 2017 Published by Elsevier Ltd. All rights reserved.