Model for the differentiation of temperature and electric field effects during thermal assisted PEF processing

Food Preservation by Pulsed Electric Fields: An Engineering Perspective

“…According to Toepfl et al [86], a linear and uniform electric field distribution can be achieved using the parallel configuration; nevertheless, treatment intensity is reduced in boundary regions depending on the product and processing parameters. Its low resistance results in unwanted high current flow and consequently in higher energy requirements to achieve specific electrical field [53]. On the other hand, although co-axial and co-linear treatment chambers have a less uniform electric field distribution, which depends on constructional properties, they are easy to clean and have a high load resistance [29,50,[86][87][88].…”

Moderate and high intensity pulsed electric fields : Effect on microbial inactivation, shelf life and quality of fruit juices

“…PEF studies carried out using high intensity pulses claim that enzyme inactivation is predominantly caused by thermal effects (> 90 %), rather than by the voltage pulses themselves (Jaeger et al, 2010;Van Loey, Verachtert & Hendrickx, 2002), which seems to be confirmed in the present study using pulses with moderate intensity. 45°C 48°C 51°C 54°C 57°C 60°C 63°C 66°C 69°C 72°C 75°C 78°C 81°C 84°C 87°C 90°C LH …”

“…However, it could not be excluded that local hot spots in the PEF treatment chamber might be responsible for a higher enzyme inactivation in the combined thermal-PEF treatment as suggested by Van Loey, Verachtert & Hendrickx (2002). This issue could also occur in our situation, while the effect could not be incorporated in the thermal inactivation model that acts as a reference (Jaeger et al, 2010). Another factor that might contribute to (additional) enzyme inactivation is by electrochemical reactions at the electrode surface.…”

“…In general, a more severe PEF treatment or combination of PEF with a higher temperature is required for reduction of enzyme activity than for the reduction of microbial activity (Grahl & Märkl, 1996;Ho, Mittal & Cross, 1997), although exceptions are reported (Jaeger et al, 2010). As some enzymes have interesting functionalities for the food industry, a food product could be treated with high intensity PEF to inactivate microorganisms, while maintaining the activity of useful enzymes .…”

Emerging Technologies for Targeted Food Processing

“…Reports on the effects of PEFs on enzymes are limited, and different experimental setups and processing parameters make them difficult to compare . Thermal effects were also found to contribute to enzyme inactivation during PEF treatment (Jaeger et al 2009;Jaeger et al 2010). The first large-scale industrial applications were carried out for the disintegration of plant raw materials such as sugar beet and fruit mashes (Bluhm and Sack 2009).…”