Non thermal pasteurization for orange juice using pulsed electric field

Abstract

Pasteurization is an act or a process to minimize or eliminate all forms of life, particularly microorganisms in food products. Its aim is to reduce or eliminate the number of viable pathogens, which are likely to cause diseases. Pasteurization can be in the form of thermal and non-thermal methods. Thermal pasteurization typically uses high heat and temperature to reduce or eliminate microorganisms. Although this method has been practiced and proven effective, the process is associated with many side effects. Due to this problem, new approaches using a non-thermal pasteurization to generate pulsed electric field (PEF) is proposed. In this paper, non-thermal sterilization using Cascaded H-Bridge Multilevel Inverter (CHMI) pulse power generator was evaluated in order to produce pulsed electric field in inactivating of microorganisms such as Saccharomyces cerevisiae and Escherichia coli in orange juice. The experimental set-up was conducted where an orange juice was placed inside the treatment chamber. The electrodes between the treatment chamber were applied with pulsed electric field up to 15 kV/cm by using the CHMI. The hardware development was implemented using MOSFET 2K3748 power devices and the gate signal generator was controlled by using dSPACE DS 1104. The experimental results show that, an output voltage of 1.2 kVp−p was effective to inactivate Escherichia coli and Saccharomyces cerevisiae. Thus, power consumption was decreased and energy was saved. The pulsed width of 1000 μs with repetitive rate of 50 Hz was generated from the hardware implementation. The results proved that the specifications of the experimental set-up meet the requirements for liquid food sterilization, particularly to inactivate Escherichia coli and Saccharomyces cerevisiae microorganisms in orange juice by using streaking plate techniques.