Palm | Kelapa Sawit

ABSTRACT: A high voltage process in food and wastewater processing, called Pulsed Electric Field processing (PEF), destroys plant and animal cells in a liquid media through electroporation. In PEF, a series of short, high voltage pulses breaks the cell wall, by expanding existing pores in the cell until they burst. This bursting of the cell wall has three main effects. It kills living cells, such as bacteria, making it an alternative to pasteurization for liquid foods, such as fruit juices and beer.

It releases the contents of the burst cell to the surrounding liquid, which can aid in the extraction of sugars and starches from plant cells, such as sugar beets. Finally, the burst cells are much more susceptible to other biological and chemical processes, such as anaerobic digestion, which can significantly reduce the solid content (sludge) in wastewater treatment facilities. PEF processing is currently being demonstrated for all three of these applications, and is beginning to emerge as a viable commercial process. In liquid foods, PEF maintains the fresh taste lost in heat pasteurization, because it is non-thermal.

PEF utilizes less than 10% of the delivered energy required for pasteurization, so the temperature rise during PEF is only a few degrees Celsius for equivalent bacterial kill (versus 80 – 100 Cº for pasteurization). Because PEF only applies a voltage gradient to the treated liquid, without arcing, there are essentially no chemical effects. In taste tests conducted on PEF treated juices, they are essentially indistinguishable from fresh (untreated) juices. In 2000, Diversified Technologies, Inc. (DTI) of Bedford, MA designed, built, and installed the first commercial scale Pulsed Electric Field (PEF) system at Ohio State University’s Department of Food Technology (FIGURE 1). This PEF system is part of a new food treatment system assembled by a DoD sponsored, universitydirected industry consortium. The purpose of the program was to research the use of high voltage pulsed power to kill microorganisms, including pathogens, in liquid oods such as juices. This system has been successfully utilized over the last two years to prove that PEF processing is scalable to high volume, commercial applications. In this paper we will describe the architecture of the pulsed power system and the application and benefits of solid-state high voltage systems to food sterilization. Operational results and status will also be presented.