超临界CO2对哈密瓜汁中大肠杆菌的杀灭效果研究

Effects of Supercritical Carbon Dioxide on the Inactivation of Escherichia coil in Hami Melon Juice

以哈密瓜汁中的大肠杆菌为研究对象,采用超临界CO2技术(压力10、20、35 MPa,温度35、45、55℃),以温度、压力、保压时间为自变量,以大肠杆菌存活对数为因变量,对哈密瓜汁中大肠杆菌进行超临界CO2(SCCO2)杀菌效果的研究。采用一级反应动力学模型分析超临界CO2对大肠杆菌的杀菌动力学;采用透射电镜观察超临界CO2对大肠杆菌超微结构的影响。试验结果表明,在35~55℃、10~35 MPa的条件下对哈密瓜汁中大肠杆菌进行超临界二氧化碳处理,灭菌速率分为先快后慢两个阶段;随温度和压力的提高,大肠杆菌的灭菌速率均逐步上升;经超临界二氧化碳处理后,大肠杆菌细胞出现明显的缺陷,部分细胞壁消失。

In this study,with Escherichia coli in fresh hami melon juice as the research object,the temperature,pressure,and processing time as the independent variable,and the logarithmic of the survival Escherichia coli as the dependent variable,we studied the sterilization effect of supercritical CO2 technology(SCCO2)(10,20,35 MPa,35,45,55℃)on Escherichia coli in fresh Hami melon fruit juice.The first order reaction kinetics model was used to analyze the sterilization kinetics of Escherichia coli by supercritical CO2 technology,and transmission electron microscope was applied to observe the effect of supercritical CO2 on ultrastructure of E.coli.Results showed that,the inactivation rate of E.coli by the treatment of supercritical carbon dioxide(SCCO2)at 35~55℃and10~35 MPa had a trend of first fast and then slow,raised gradually with the increase of temperature and pressure,and obvious cell defects were found and partial cell walls disappeared after supercritical carbon dioxide treatment.