A solid state pulsed power system for food processing

Abstract

In 2000, Diversified Technologies, Inc. (DTI) of Bedford, MA designed, built, and installed the fKst commercial scale Pulsed Electric Field (PEF) system at Ohio State University's Department of Food Technology (Fig. 1). This PEP system is part of a new food treatment system assembled by a DoD sponsored, universitydirected industry consotlium. The purpose of the program is to research the use of high voltage pulsed power to kill microorganisms, including pathogens, in liquid foods such as juices. The process, called Pulsed Electric Field processing (PEF), maintains the fresh taste of foods lost in heat pasteurization, because it IS non-thermal.This solid state pulsed power system provides bipolar 60kV. 600A pulses at 75kW average power into four PEF treatment chambers. It consists of two fully independent switching power supplies and solid state switches -one at positive voltage, and the other at negative voltage. This provides a very high level of pulse flexibility to the OSU researchers as they optimize PEF treatment parameters across a wide range of liquid foods.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.

Hybrid Energy Storage and Applications Based on High Power Pulse Transformer Charging

“…Besides, the HES cell is also used in shockwave generator [17], dielectric barrier discharge [18], industrial exhaust processing [19], material surface treatment [20], ozone production [21], food sterilization [22], cell treatment and cell mutation [23]. …”

“…In volume Vb which is occupied by the secondary winding wires themselves, Wmb can be estimated as 22 …”

An innovative and non-invasive technology for PEF food processing

“…In commercially available systems for PEF processing, production of the required voltage pulses uses either conventional Blumlein generators or generators similar to those found in radar power sources [5], both with a high pulse rate. The liquid is passed through a number of treatment chambers or cells, in each of which it is exposed to a number of pulses.…”

“…This technology is therefore termed invasive, and it can be used only with liquid (or pumpable) food! To the best of the authors' knowledge, Diversified Technologies in the USA is the only present manufacturer of industrial scale PEF machines [5] and at least one company in the USA (Genesis, [6]) uses the technique in the processing of a range of fruit juices with an extended shelf life of up to four weeks. A significant feature of their advertising is that, due to the relatively low temperature attained, the flavor of the product is much better than that of those produced by conventional pasteurization.…”

Demonstration of a Novel Pulsed Electric Field Technique Generating Neither Conduction Currents Nor Joule Effects

“…Commercially available systems for PEF processing (e.g., [7,8]) all use irreversible electroporation, with a pulsed power generator having a high pulse rate producing the required voltage pulses. The liquid is passed through a relatively large number of treatment chambers or cells, in each of which it is exposed to a series of pulses.…”