脉冲电场预处理胡萝卜片微波干燥试验

Experiments on microwave drying of carrot slices using pulsed electric field pre-treatment

为考察脉冲电场预处理对胡萝卜片微波干燥特性的影响,以胡萝卜片微波干燥单位时间降水率和复水率作为试验指标,设计了4因素(脉冲频率、电场强度、微波功率密度和切片厚度)二次回归正交组合试验,得出经预处理后胡萝卜片微波干燥失水速率曲线。用SPSS软件进行回归分析,得到预处理后胡萝卜片微波干燥动力学方程和各指标回归方程,并对指标进行了综合优化。结果表明:经脉冲电场预处理后胡萝卜片微波干燥动力学方程分段适用Page模型;脉冲频率和电场强度对胡萝卜片微波干燥单位时间降水率影响显著;脉冲频率对复水率影响显著,电场强度对复水率影响不显著;最优工艺组合为脉冲频率30Hz、电场强度2.0kV/cm、微波功率密度1.0W/g和切片厚度4.0mm;在最优工艺条件下,胡萝卜片单位时间降水率和复水率均得到提高。

In order to study the effects of pulsed electric field（PEF）pre-treatment on microwave drying characteristics of carrot slices,according the experiment indexes of average drying rate and rehydration ratio of carrot slices,four factors（pulse frequency,electric field strength,microwave power intensity and thickness）,quadratic regression orthogonal experiments on microwave drying of carrot slices with PEF pre-treatment were conducted.The curves of dehydration rate of microwave drying carrot slices were obtained.The equations of drying kinetics and indexes were gotten by regression analyzing with SPSS,and the indexes were synthetically optimized as well.The results showed that the Page’s model was better for the microwave drying kinetics of PEF pre-treated carrot slices;the average drying rate was markedly influenced by pulse frequency and electric field strength;the rehydration ratio was markedly affected by pulse frequency,but it was not done by electric field strength.The optimal combinations of parameters were pulse frequency 30 Hz,electric field strength 2.0 kV/cm,microwave power intensity 1.0 W/g and thickness 4.0 mm.Under the optimal condition,the average drying rate and rehydration ratio of carrot slices were improved.