大肠杆菌射频加热杀菌效果及动力学模型拟合  

Inactivation Effect and Inactivation Kinetics of Escherichia coli by Radio Frequency Heating

作　　者：雷玉洁[1] 周良付 李宇坤[1] 郭超凡[1] 张永迪 赵慧 王云阳[1] Lei Yujie;Zhou Liangfu;Li Yukun;Guo Chaofan;Zhang Yongdi;Zhao Hui;Wang Yunyang(College of Food Science and Engineering, Northwest A＆F University, Yangling 712100, Shaanxi;Department of Chemistry and Biology, Dongchang College of Liaocheng University, Liaocheng 252000, Shandong)

机构地区：[1]西北农林科技大学食品科学与工程学院,陕西杨凌712100 [2]聊城大学东昌学院化学与生物系,山东聊城252000

出　　处：《中国食品学报》2018年第4期132-138,共7页Journal of Chinese Institute Of Food Science and Technology

基　　金：国家自然科学基金项目(31171761);陕西省科学技术研究发展计划项目(2014K13-14)

摘　　要：为研究射频加热杀菌效果及微生物致死动力学。选取大肠杆菌为试验菌株,研究极板间距和菌悬液电导率对加热速度及杀菌效果的影响。选取4种常见的模型,即一级动力学、Weibull、Dose-response和Log-Logistic模型对大肠杆菌射频加热失活曲线进行动力学模型拟合。结果表明:极板间距和电导率影响射频加热速度,极板间距越大升温速度越慢,杀灭微生物所需时间越长,当电导率接近1 000μs/cm时,升温速度最快。在极板间距115 mm,电导率1 083μs/cm的条件下,加热90 s,大肠杆菌致死率即可达100%。大肠杆菌的失活动力学曲线基本呈倒"S"型,不符合一级反应动力学模型。Weibull、Log-Logistic和Dose-response模型都能较好地拟合射频杀菌失活曲线。通过对模型的拟合评价参数,即精确因子Af、偏差因子Bf、根平均方差RMSE和决定系数R2的比较,确定Log-Logistic模型拟合效果最好。To study the microbe inactivation effect and lethal kinetics by radio frequency（RF） heating, Escherichia coli was selected as the test strain to study effects of the electrode gaps and electrical conductivity of bacterial suspensions on heating rate and inactivation. Four commonly used models as Linear, Weibull, Log-Logistic and Dose-Response models were used to fit inactivation curves of E. coli by RF heating. Results showed that both electrode gap and conductivity affected RF heating rate. The larger of electrode gap, the slower of heating up was, and the longer time needed for killing bacteria. When the electrical conductivity was close to 1 000 μs/cm, heating up speed was the fastest. Under electrode gap of 115 mm and conductivity of 1 083 μs/cm, it took 90 s of heating time for 100% lethal rate of E.coli. The inactivation curve of E. coli was reverse ＂S＂ type, which was not complying with the Linear kinetics. Weibull model, Log-Logistics Model and Dose-Response model could all fit the inactivation curve well. The fitness of the three models were evaluated by using a series of indices including Accuracy Factor（Af）, Bias Factor（Bf）, Root Mean Square Error（RMSE） and the correlation coefficient（R2）. Log-logistic model provided the best fitness.

关 键 词：射频加热 大肠杆菌 杀菌动力学 模型拟合 

分 类 号：TS201.3[轻工技术与工程—食品科学]