Experimental Evaluation of Water Contamination in a Non- Thermal Food Processing System Utilizing an Underwater Shockwave Kei Eguchi 1 , Farzin Asadi 2 , Hiroto Abe 1 , and Ichirou Oota 3 1 Department of Information Electronics, Fukuoka Institute of Technology,3-30-1 Wajirohigashi, Higashi-ku, Fukuoka, 811-0295 Japan 2 Mechatronics Engineering Department, Kocaeli University, Umuttepe Yerleşkesi 41380, Kocaeli, Turkey 3 Department of Electronics Engineering and Computer Science,National Institute of Technology, Kumamoto College, 2659-2 Suya, Koushi-shi, Kumamoto, 861-1102 Japan Abstract: Recently, as a low-cost non-thermal food processing technique, the food processing technique utilizing an underwater shockwave is receiving much attentions. In the non-thermal food processing system, the underwater shockwave is generated by discharging a high voltage between metal electrodes, where copper electrodes or aluminium electrodes are usually used as electrode materials in order to perform the non-thermal food processing. By utilizing underwater shockwaves, only the internal tissue of a target food can be disrupted without heating. However, a part of the electrodes is melted by the high electric discharge. In this paper, we focused on water contamination caused by the metal electrode which dissolved in water. As far as the authors know, the water contamination has not been investigated in past studies, though there is a possibility that the water contamination has an influence on human bodies. In this paper, we conducted the experimental evaluation of water contamination in the non-thermal food processing system utilizing an underwater shockwave. By using a water examination device, the contamination caused by copper electrodes was investigated for 100 samples. The experimental result showed that the copper concentration in the water of the pressure vessel was 0.33 mg/L at 17.5 degrees Celsius. The degree of thickness of the contaminated water was less than the standard copper value in the water quality standard for Japanese drinking water. Keywords: Cockcroft-Walton multipliers, Non-thermal food processing, Underwater shockwaves, Water contamination. 1. Introduction For our healthy life, the development of effective food processing technologies is a vital issue. In recent years, non-thermal food processing [1] attracts many researchers' attention, because the non-thermal food processing technology can provide nutritious foods without destroying nutrients with an increase in temperature. For this reason, several types of non-thermal food processing technologies have been developed in past studies, for example, High Hydrostatic Pressure (HHP), High Voltage Arc Discharge (HVAD), and Cold Plasma (CP). Among others, we focused on the non-thermal food processing technology utilizing an underwater shockwave [2, 3], because it is advantageous in regards to cost. In the first non-thermal food processing system, explosive was used to generate an underwater shockwave. However, due to the safety reasons, a high voltage multiplier is used to generate the underwater shockwave in recent years. The operation principle of a current non-thermal food processing system is as follows: First, a high stepped-up voltage which is generated by the high voltage multipliers is stored in a big capacitor. Then, electrical energy stored in the big capacitor is discharged in a pressure vessel filled with water. In this timing, a ISBN 978-93-84422-80-6 7th International Conference on Advances in Science, Engineering, Technology and Natural Resources (ASETNR-17) Dec. 27-28, 2017 Pattaya (Thailand) https://doi.org/10.17758/ERPUB.ER12174007 1