title: Thermal and high-pressure inactivation kinetics of polyphenol oxidase in Victoria grape must.
abstract: The inactivation kinetics of polyphenol oxidase (PPO) in freshly prepared grape must under high hydrostatic pressure (100-800 MPa) combined with moderate temperature (20-70 degrees C) was investigated. Atmospheric pressure conditions in a temperature range of 55-70 degrees C were also tested. Isothermal inactivation of PPO in grape must could be described by a biphasic model. The values of activation energy and activation volume of stable fraction were estimated as 53.34 kJ mol(-1) and -18.15 cm3 mol(-1) at a reference pressure of 600 MPa and reference temperature of 50 degrees C, respectively. Pressure and temperature were found to act synergistically, except in the high-temperature-low-pressure region where an antagonistic effect was found. A third-degree polynomial model was successfully applied to describe the temperature/pressure dependence of the inactivation rate constants of the stable PPO fraction in grape must.
authors.affiliation: Faculty of Food Science and Engineering, Department of Bioengineering, University "Dunaren de Jos" Galati, Domneasca 111, 800201 Galati, Romania.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Rapeanu
authors.forename: Ann
authors.initials: A
authors.lastname: Van Loey
authors.forename: Chantal
authors.initials: C
authors.lastname: Smout
authors.forename: Marc
authors.initials: M
authors.lastname: Hendrickx
mesh_terms: D004156:Catechol Oxidase / Q000737:chemistry / Q000378:metabolism*; D004789:Enzyme Activation; D005638:Fruit / Q000201:enzymology*; D006358:Hot Temperature; D006874:Hydrostatic Pressure; D007700:Kinetics; D013816:Thermodynamics; D027843:Vitis / Q000201:enzymology*
chemical_list: D004156:Catechol Oxidase