脉冲电场预处理马铃薯片微波干燥动力学研究

Microwave Drying Kinetics of Potato Slices with Pulsed Electric Field Pre-treatment

采用自制脉冲电场(Pulsed electric field:PEF)装置,研究了不同脉冲频率和电场强度预处理对马铃薯片微波干燥特性的影响.设计了3因素(脉冲频率、电场强度、微波功率密度)2指标(脱水速率和厚度比)二次回归正交组合试验.对试验结果采用SPSS软件进行回归分析,得出PEF预处理后马铃薯片微波干燥动力学方程和2指标回归方程.结果证明,经PEF预处理后马铃薯片微波干燥速率快于未经预处理的马铃薯样品;马铃薯微波干燥方程分段适用Page模型;试验验证了干燥动力学方程和回归方程的预测性都较好(p<0.05).采用MATLAB软件对2指标回归方程进行综合优化,得到可供参考的脉冲电场预处理马铃薯片微波干燥工艺参数,即脉冲频率、电场强度、微波功率密度分别为30 Hz、1.0 kV/cm、1.0 W/g.

The objective of this study is to evaluate the influence of pulsed electric field （PEF） pretreatment parameters such as pulse frequency, electric field intensity on microwave drying characteristics of potato slices. Potato slices are treated in PEF system of 30, 45 and 60 Hz pulse frequency, 1.0, 2.0 and 3.0 kV/cm electric field intensity. The samples are dried by microwave power intensity of 0. 6, 0. 8 and 1.0 W/g until reaching an acceptable moisture content level. The equations of ratio） are obtained by series regression orthogonal show that the PEF pre -treated samples have higher is fitted to the microwave drying drying kinetics and indexes （dehydration rate and thickness experiments and regression analysis with SPSS. The results drying rate than the un - treated samples. The Page＇s model curve of PEF pre - treated potato slices and coefficients of regression equation are significantly （p 〈 0. 05 ） influenced by PEF treatment. The indexes are synthetically optimized in software MATLAB as well. The results are pulse intensity 1.0 W/g. The models of drying frequency 30 Hz, electric field intensity 1.0 kV/cm, microwave power kinetics and indexes could describe and predict the change microwave drying of potato slices very well according regulation of to the comparison of experimental and calculated values.