Kinetics of combined pressure-temperature inactivation of avocado polyphenoloxidase

Abstract

Irreversible combined pressure‐temperature inactivation of the food quality related enzyme polyphenoloxidase was investigated. Inactivation rate constants (k) were obtained for about one hundred combinations of constant pressure (0.1–900 MPa) and temperature (25–77.5°C). According to the Eyring and Arrhenius equation, activation volumes and activation energies, respectively, representing pressure and temperature dependence of the inactivation rate constant, were calculated for all temperatures and pressures studied. In this way, temperature and pressure dependence of activation volume and activation energy, respectively, could be considered. Moreover, for the first time, a mathematical model describing the inactivation rate constant of a food quality‐related enzyme as a function of pressure and temperature is formulated. Such pressure‐temperature inactivation models for food quality‐related aspects (e.g., the spoilage enzyme polyphenoloxidase) form the engineering basis for design, evaluation, and optimization of new preservation processes based on the combined effect of temperature and pressure. Furthermore, the generated methodology can be used to develop analogous kinetic models for microbiological aspects, which are needed from a safety and legislative point of view, and other quality aspects, e.g., nutritional factors, with a view of optimal quality and consumer acceptance. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 60: 292–300, 1998.

Thermal Inactivation Kinetics of Peroxidase in Coriander Leaves

“…Also, because of the variation of the reaction order (n) with processing temperature from 4.42 at 70°C to 0.75 at 93°C (Table 3) and collinearity between the estimated parameters, n and k (R 2 >0.8), this model did not describe the inactivation behavior accurately. Similar observation has been reported by Weemaes et al (1998). The fractional conversion model (Eq.…”

“…3 in Table 1) and fractional conversion model (Eq. 4 in Table 1) to describe thermal inactivation of enzymes have been used by several researchers (Lourencüo et al 1990;Robert et al 1995;Rizvi and Tong 1997;Weemaes et al 1998). A r in fractional conversion model is the enzyme activity for most resistant enzyme fraction.…”

Influence of Process Conditions on Measles Virus Stability

“…Virus inactivation in general was reported to proceed similar to cell dying (Bauer and Henle, 1979;Johnson, 1974) or protein and enzyme inactivation (Weemaes et al, 1997;1998). All reports about MV stability in general have been published decades ago.…”

High pressure and thermal inactivation kinetics of polyphenol oxidase and peroxidase in strawberry puree

“…Antagonistic effect between moderate pressure (P < 400 MPa) and temperature has been reported for many enzymes including pectin methylesterase (Guiavarc'h, Segovia, Hendrickx, & Loey, 2005;Van den Broeck, Ludikhuyze, Van Loey, Weemaes, & Hendrickx, 1999), polyphenol oxidase (Weemaes, Ludikhuyze, Van den Broeck, & Hendrickx, 1998;Dalmadi et al, 2006) and lipoxygenase (Indrawati, Van Loey, Ludikhuyze, & Hendrickx, 2001;Rodrigo et al, 2006). The stabilisation of enzymes by high pressure against thermal inactivation has been ascribed to the opposing effects of pressure and temperature on the formation or disruption of intramolecular interactions and/or the interaction between the functional groups of the protein and the solvent (usually water), which affect the structure, functionality and stability of the protein (Balny & Masson, 1993;Mozhaev, Lange, Kudryashova, & Balny, 1996).…”