Experimental Research About High Voltage Pulsed Electric Field Sterilization

With the improvement of people’s living standards, consumers have become increasingly demanding on food safety, nutrition, natural and other aspects. The traditional food processing technology can no longer satisfy consumer’s demands. Food workers pay attention on the technology of food processing to assure not only the safety of food, but also preserving color, flavor. At present, sterilization technology which is mainly used in liquid foods at home and abroad is pasteurization. However, heat sterilization technology is not applicable for some food. It will make food take place physical and chemical changes. The technology of cold sterilization has drawn greater attention in recent years,and it includes ultrasonic sterilization, ultra-high pressure sterilization, high-voltage pulsed electric field sterilization, magnetic fields sterilization and so on. As a new technology sterilization, high-voltage pulsed electric field sterilization is considered to be the most promising method and can achieve the industrial application.High-voltage pulsed electric field is a new technology which could kill harmful micro-organisms in liquid foods in recent years, it has the characteristic of safe, shorten sterilization time, less energy consumption, high efficiency, basically do not undermine flavor and nutrients of food, but could also avoid adverse effects as the heat treatment brought.In recent years, plenty of researches were carried out about PEF sterilization technology, but there is a certain distance away from commercialization. Researchers need to explore the mechanism of PEF sterilization, to improve the pulsed electric field sterilization equipment, advance the best terms for the pulsed electric field sterilization, and then design a set of affordable sterilization device to realize the rapid industrialization.By reading the extensive literature on the subject at home and abroad, we have designed a high-voltage pulsed electric field sterilization equipment, and also improve the wave by doing experiment on the PEF sterilization. The following work has been carried out:Firstly, contrast the heat sterilization to various non-heat sterilization and summarize the advantages and disadvantages of those; expatiate the development process of pulsed electric field sterilization techniques; discusses the mechanism and model of inactivation when micro-organisms in pulsed electric field, and the main factors which were affecting PEF sterilization were discussed in detail.Secondly, the overall structure of PEF sterilization system has been designed, using the software Ansys9.0 to deal with the simulation analysis. Study the sterilizing efficiency of liquid foods with bipolar exponential decay wave power in different treatment rooms, and explores the factors affecting the PEF sterilization. Finally, experimental results show that the pulse wave is a key element to affect PEF sterilization efficiency, a project is proposed to improve bipolar index pulse pair wave, and design a set of device whose frequency, pulse width can be adjusted,. Through the circuit test, the device can achieve the ideal experimental requirements.