Process Considerations on the Application of High Pressure Treatment at Elevated Temperature Levels for Food Preservation [article]

Adriano Ardia, Dietrich Knorr, Technische Universität Berlin, Technische Universität Berlin
2004
Among the new emerging technologies which are proposed to allow quality retention or minor quality damages in food products, High Hydrostatic Pressure (HPP) is considered to be a real and efficient alternative process to the most used and common industrial techniques for food preservation since it offers a chance of producing food of high quality, greater safety and increased shelf-life. It is the aim of this work to explore ways in which high pressure can be used to achieve sterilization of
more » ... sterilization of most resistant microbial species in foods in which conventional thermal processing fails to obtain competitive high-quality products. In order to match these requirements, considerations on the process itself and on possible process improvements have been developed which take into account for the physics of the pressure build-up phase. Studies on modelling the adiabatic heat of compression of basic fluids and on the inactivation of vegetative cells and sporeforming bacteria in different media at low pressure levels (700 MPa) and within short compression times have been done. In order to proof that a gradient of temperature may result in a non-uniform spatial inactivation in the product sample, a mathematical model, which was developed to follow the thermal increase during the build-up phase of fluid systems, was implemented into a self-made software which was performed to predict the microbial inactivation of vegetative cells and spore-forming bacteria as function of the spatial temperature distribution in the product during the whole pressure treatment. On the base of results which were obtained at low pressure conditions (700 MPa), an innovative high pressure unit was designed which allowed the generation of higher pressure levels (1400MPa) in short times (less than 20 s) and in adiabatic conditions. The set-up of the ultra-high pressure unit was performed, by which it was possible to carry out investigations on the adiabatic heat of compression of different fluids, in a wide range of pressure and temperature, and it was po [...]
doi:10.14279/depositonce-840 fatcat:burodzs4vvgo7psettz7iknnla