脉冲电场灭菌中液体食品击穿机理研究

As a most promising non-thermal sterilization of liquid food processing technology, the high-voltage pulsed electric field sterilization technology has been widely researched by the staff of researchers in the mechanism of sterilization, the effect of sterilization and the food nutrients effect. However, in practical applications, because of the high level electric field strength which is necessary for food sterilization, the processed liquid food often take place abnormal breakdown during processing. Could not only lead to the processing liquid food to be contaminated, but will also cause damage to the high voltage pulse power supply, this has become the bottleneck in the application of this technology. The breakdown mechanism and its influence factors of the liquids food in pulsed electric field will be studied in the project, in order to obtain the knowledge related with liquid food in a pulsed electric field about the breakdown mechanism and the influence of the temperature, pressure, flowing state of the liquid, the solid and gaseous substances, uniform electric field, duration of the voltage and its rise speed. The purpose of the research is to fill the vacancies of the knowledge related with breakdown of liquid food in a pulsed electric field, and settle the foundation for the industrial application of high voltage pulsed electric field sterilization technology, and finally, in order to solve the technology bottlenecks which restricts the industrial application of pulsed electric field sterilization technology for a long time.

高压脉冲电场灭菌技术作为一种最具应用前景的液体食品非热力灭菌技术受到了科研人员和食品加工技术人员的普遍关注，并开展了脉冲电场的灭菌机理、对食品营养成分的影响、灭菌效果的影响因素等方面的研究。但是，由于被处理液体食品在高电场下经常会出现异常击穿，不仅有可能导致被处理液体食品受到污染，而且会造成高压脉冲电源的损坏，已经成为这项技术应用的瓶颈。本项目将首先利用现代快速摄影技术对液体食品在脉冲电场作用下的击穿过程进行观测和记录，然后，结合以往在绝缘液体击穿机理方面的研究成果，探索出液体食品在脉冲电场作用下的击穿机理，并对温度、压力、液体运动状态、液体中固体物质和气体物质含量、电场均匀性、电压作用时间和电压上升速度等影响因素对击穿过程的影响进行研究。目的在于填补脉冲电场作用下液体食品击穿方面的认识空缺，为高压脉冲电场灭菌技术工业化推广应用奠定基础。解决长期制约高压脉冲电场灭菌技术推广应用的技术瓶颈。

脉冲电场灭菌过程中被处理液体食品的异常击穿，不仅有可能导致被处理液体食品受到污染，而且会造成高压脉冲电源的损坏，已经成为高压脉冲电场灭菌技术应用的瓶颈。本项目通过建立实验平台，实验研究了压强、液体流量、液体中气体含量、电场均匀性和电压作用时间等因素对脉冲电场作用下液体食品击穿过程的影响；通过高速和超高速光学记录设备观察、记录了脉冲电场作用下液体食品击穿的过程，提出了脉冲电场作用下液体食品击穿的机理；提出了一种测定高导电性液体电学参数的脉冲电压法；研制了一种自动保护IGBT的固态开关高压脉冲发生器和一套连续生产型高压脉冲灭菌装置。