食品的介电特性在食品干燥过程中的在线无损检测技术

A Study of Using Food Electric Properties as a Non Destructive and Continuous Measurement in a Drying Process

选用标准蔗糖、新鲜胡萝卜、葱、蘑菇和生菜为原料,研究干燥过程中原料电特性参数电容和水分含量的变化规律以及它们之间的相关性。结果表明60℃温度下热风干燥几种新鲜蔬菜,其水分含量随着干燥时间的延长而下降,到一定的水分含量后质量不再发生变化,电容的变化趋势与水分的变化相同,质量不变时电容也趋于恒定,两者之间存在极显著的线性正相关性,说明干燥过程中水分含量的测定可以用检测相对应点的电容值来计算,从而实现在线、无损监控食品干燥过程。

A relationship between moisture and capacitance of foods drying process is proposed. Pure sucrose solution, carrot, mushroom, lettuces and welsh onion were used as samples. The results showed significant correlation between the capacitance of each sample and moisture content. The moisture content and capacitance decrease with increase in drying time for every sample at 60℃ during drying process. The capacitance won＇t change until the moisture content arrived at a certain content. This technique will enable us to control drying conditions automatically without sampling the material during the drying process.