University of Natural Resources and Life Sciences, Vienna (BOKU) - Research portal
Gewählte Doctoral Thesis:
Felix Tobias Schottroff
(2020):
Tailoring electrotechnologies for microbial inactivation in food and bioprocess engineering – Inactivation mechanisms, processing concepts, and equipment design.
Doctoral Thesis - Institut für Lebensmitteltechnologie,
BOKU-Universität für Bodenkultur,
pp 198.
UB BOKU
obvsg
- Abstract:
- Processes employing a direct application of electric fields (so-called electrotechnologies), such as pulsed electric fields (PEF) or ohmic heating, are used in food and bioprocessing for the inactivation of microorganisms. PEF treatment uses high voltage pulses, which enable inactivation of microorganisms by electroporation at lower process temperatures compared to conventional thermal pasteurization. Ohmic heating, on the other hand, uses lower voltage alternating current to heat products quickly and uniformly. In the present work, an adaptation approach was used to tailor electrotechnologies for applications in food and biotechnology and to close gaps in the current state of research. With this regard, effects and inactivation mechanisms of ohmic heating on vegetative microorganisms and bacterial endospores were investigated, application studies were performed using ohmic heating and PEF, and an optimized treatment chamber design was constructed and evaluated. The results showed that the electric field present during ohmic heating had no additional effect on vegetative microorganisms, but for bacterial endospores, a pronounced additional inactivation was observed, which could be attributed to interactions of the electric field with proteins in the core of the spore. Furthermore, an effective decontamination of protein formulations could be achieved during the conducted application studies, depending on the individual process parameters and product properties. However, the limits of these technologies have also been demonstrated in this context. Lastly, a vortex-based treatment chamber was designed to achieve increased treatment homogeneity.
- Betreuer: Jäger Henry
- 1. Berater: Domig Konrad
- 2. Berater: Zunabovic-Pichler Marija