A modeling approach for evaluating process uniformity during batch high hydrostatic pressure processing: combination of a numerical heat transfer model and enzyme inactivation kinetics

Denys, Siegfried; Loey, Ann Van; Hendrickx, Marc

doi:10.1016/s1466-8564(99)00003-x

Cited by 117 publications

(79 citation statements)

References 7 publications

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“…Concerning the kinetic data for the high-pressure inactivation, the closed form representation of Denys et al (2000) similar to that of Ludikhuyze (1997b) has been applied in the current work. It is implemented as the source term of Eq.…”

Section: Methodsmentioning

confidence: 99%

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Numerical simulation of convective and diffusive transport effects on a high‐pressure‐induced inactivation process

Hartmann

Delgado

2002

Biotech & Bioengineering

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High-pressure-induced conversions, such as the inactivation of enzymes or of microorganisms, are dependent on the applied pressure and the temperature of the process. The former can be considered to be a spatially homogeneous quantity, while the latter, being a transport quantity, varies over space and time. Here we question whether the uniformity of a high-pressure conversion can be disturbed by convective and conductive heat and mass transport conditions. Enzyme inactivation is taken as a model process for a high-pressure conversion. To cover a broad range of parameters and to consider scale-up effects, the investigation is based on mathematical modeling and numerical simulation for different sizes of the pressure chamber and different solvent viscosities. Apart from viscosity, the physical properties of the enzyme solutions are assumed to be identical in all cases. Therefore, matrix effects other than that of viscosity are excluded. Moreover, the authors postulate that viscosity solely acts on the continuum mechanical scale of momentum exchange but not on the molecular scale on the inactivation kinetics. It has been found that nonuniform thermal conditions can strongly influence the result of a high-pressure process. A variation of the activity retention between 28% and 48% can be observed after 20 minutes for a 0.8-L high-pressure chamber and a matrix fluid with a viscosity comparable to that of edible oils. The same process carried out in a 6.3-L device leads to an activity retention that varies between 16% and 40%. From the analysis of the time scales for the inactivation and for hydrodynamic and thermal compensation, it can be deduced that a nonuniform activity retention has to be expected if the inactivation time scale is larger than the hydrodynamic time scale and smaller than the thermal compensation time scale.

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Section: Methodsmentioning

confidence: 99%

“…The inactivation model was based on data obtained for Bacillus subtilis a-amylase in a (liquid) TrisHCl buer. Denys et al (2000) investigated the process uniformity of the inactivation of Bacillus subtilis a-amylase and soybean lipoxygenase in apple sauce and tomato paste. The relevant physical properties were determined experimentally.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of convective and diffusive transport effects on a high‐pressure‐induced inactivation process

Hartmann

Delgado

2002

Biotech & Bioengineering

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“…Efecto de la alta presión hidrostática en la exposición deL contenido de sulfhidrilos Ormando, Vranic, Guidi, Ambrosi Denys et al (2000) fueron los primeros en utilizar pTTI's para la detección de los gradientes de temperatura dentro de la cámara de APH. En este sentido, Grauwet et al (2010) evaluaron la distribución de temperaturas en un equipo APH horizontal (400-600 MPa; 10-40 °C; 1-15 min) utilizando enzimas α-amilasas bacterianas, cuya desnaturalización térmica ocurre por encima de los 80 °C.…”

Section: Revista Del Laboratorio Tecnológico Del Uruguayunclassified

Efecto de la alta presión hidrostática en la exposición de contenido de sulfhidrilos libres en amilasa fúngica

Ormando

Vranic

Guidi

et al. 2018

INNOTEC

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ResumenEl objetivo de este trabajo fue evaluar el efecto térmico residual generado luego del uso en ciclos consecutivos del equipo de Alta Presión Hidrostática (APH) en tres posiciones internas (superior, central e inferior) mediante la cuantificación del contenido de sulfhidrilos libres [SH-L] de α-amilasa de Aspergillus oryzae expresado en μmol de SH/g de proteína. La potencial utilización de la cuantificación de [SH-L] de la enzima como indicador de tratamiento de APH permite medir en forma indirecta el efecto térmico durante el proceso. En el ensayo se utilizó un equipo de APH de 2L con alimentación inferior del fluido de presurización (agua:propilenglicol-70:30v/v). En cada ciclo, el fluido a temperatura ambiente fue comprimido hasta alcanzar la presión deseada (605 MPa), y el nivel de presión se mantuvo durante cinco minutos con posterior despresurización. El ciclo fue repetido tres veces en forma consecutiva. Se realizó un ANOVA (α=0,05) correspondiente a un diseño factorial de dos factores: posiciones y ciclos consecutivos, con tres niveles cada uno, y con cuatro repeticiones para el diseño completo. Se obtuvieron diferencias significativas en la interacción ciclo*posición (p valor=0,001) y el ciclo (p valor=0,021). Estos resultados evidencian el efecto del calor generado durante la compresión adiabática, afectando la historia térmica de la α-amilasa. Dada su sensibilidad, esta enzima podría ser considerada a futuro como un indicador de procesos de APH que permite evaluar la diferencia entre las muestras procesadas durante los ciclos, y que evidencia el perfil térmico generado dentro del equipo. Palabras clave: Altas Presiones, contenido de sulfhidrilos libres, amilasa. AbstractWe evaluated the residual thermal effect generated by the consecutive High Hydrostatic Pressure (HHP) cycles relative to the position (upper, central and lower) inside a high pressure vessel determining the free sulfhydryl groups [F-SH] from pressurized α-amylase Aspergillus oryzae expressed in μmol SH/g protein. This methodology could represent a potential indicator of HHP treatment, allowing to measure in an indirect way the thermal effect during the process. Assays were carried out using a 2L stabilized lab scale equipment, where pressurizing medium (water-propilenglycol:70-30%) was injected at room temperature from the bottom of the vessel. For each cycle, the fluid at room temperature was compressed until reaching the desired pressure (605 MPa), maintained for five minutes, followed by depressurization. The cycle was repeated three consecutive times. The free sulfhydryl content was assayed statistically using one-way ANOVA (α=0,05) for a factorial design of two factors: positions and consecutive cycles, with three levels, and four repetitions for the complete design. Significant differences were obtained in the interaction cycles*position (pvalue = 0,001) and cycles (pvalue = 0,021). These results demonstrate the effect of the heat generation during adiabatic compression, affecting the thermal history of the α-amylase. Due to...

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“…By taking into account the nonuniform temperature distribution appearing during the process, it can be assured that the objective of the process has been accomplished everywhere within the food product. Most numerical models for predicting heat transfer during HPP of foods were based on conductive heat transfer [10], [11].…”

Section: Introductionmentioning

confidence: 99%

A Computer Simulation Study of High Pressure Processing of Liquid Food Using Computational Fluid Dynamics

Hussein¹

2015

IJMO

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Abstract-In the present work, the adiabatic heating during high-pressure processing of liquid food is analyzed by means of numerical simulations. Natural convection heating within a three-dimensional cylinder filled with water as a model liquid food during sterilization is simulated. Pressure is assumed to rise from atmospheric pressure to the treatment pressure of 500 MPa. The governing equations for continuity, momentum and energy conservation are solved using a commercial Computational Fluid Dynamics (CFD) package (PHOENICS), version 3.5, which is based on a finite volume method of solution. Temperature and pressure profiles within the model liquid are predicted. The simulations show that the heat transfer process after completion of the compression process is mostly controlled by conduction, which is due to the insignificant effect of natural convection (very low liquid velocity 3x10 -8 -4x10 -7 ms -1 ) as observed from the results of the simulation.Index Terms-CFD, high pressure processing, temperature distribution.

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A modeling approach for evaluating process uniformity during batch high hydrostatic pressure processing: combination of a numerical heat transfer model and enzyme inactivation kinetics

Cited by 117 publications

References 7 publications

Numerical simulation of convective and diffusive transport effects on a high‐pressure‐induced inactivation process

Numerical simulation of convective and diffusive transport effects on a high‐pressure‐induced inactivation process

Efecto de la alta presión hidrostática en la exposición de contenido de sulfhidrilos libres en amilasa fúngica

A Computer Simulation Study of High Pressure Processing of Liquid Food Using Computational Fluid Dynamics

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