Electrical sterilization of juice by discharged HV impulse waveform

Abstract

In the sterilization system by using HV impulse waveform apple juice was sterilized with HV discharged oscillatory decay waveform. The optimal condition of impulse waveform for electrical sterilization has presented the excellent condition at 40kV/cm, 4mH. The characteristic of this waveform shows oscillatory decay waveform with multiple pulses. And this impulse waveform was more effective to kill Saccharomyces cervisiae than exponential decay waveform. Saccharomyces cervisiae to become musty and sour for apple juice was used as the sample. Especially, Vitamin C content of electrical sterilized apple juice was close to that of fresh apple juice, but was much higher than that of heat treated apple juice. Heat treated apple juice lost 80% of flavor components, whereas electrical sterilized apple juice lost only 10%. This apple juice has good effect of electrical sterilization because of higher conductivity than water. Therefore this experiment can be treated sterilization without loss of vitamin C and original taste or perfume to apple juice. As a result, it is found that apple juice can be sterilized on 40kV/cm, 4mH by using our designed HV impulse sterilizer.