摘要
果蔬在外电场的作用下会呈现一定的介电特性,利用果蔬的介电特性,可以对其成分、组织和状态等品质进行分析和监控。真空冷冻干燥果蔬加工中对物料进行高压脉冲电场预处理,可以很大程度地提高果蔬干燥速率,降低能耗,并且能够很好地保持物料原有的性质,因此在探索应用介电常数检测真空冷冻水分时需要研究高压脉冲电场对果蔬介电特性的影响。为此,研究了高压脉冲电场预处理果蔬介电特性的变化规律,选取苹果和白萝卜作为试验材料,利用3532-50型LCR测试仪,在1×102～1×106Hz频率范围内测量样本的阻抗、电容、电导率等介电常数,采用ECM830型高压矩形脉冲发生器对样本进行高压脉冲电场预处理,测量经不同场强高压脉冲电场处理后样本的电特性参数,根据试验结果得出果蔬介电特性的变化规律,为进一步研究高压脉冲电场以及应用介电常数表达果蔬水分提供理论基础。
The fruits and vegetables present certain dielectric property under the role of out-electric field, people can an- alyze and monitor the composition, organization and condition of the fruits and vegetables through the dielectric property. The high pulsed electrical field （HPEF） that is applied to fruits and vegetables, which prior to the vacuum freeze-drying , can improve drying efficiency and reduce energy consumption as much as possible, and it can keep the properties of the material. Therefore it is essential to research the influence of the high pulsed electrical field pretreatment on the fruits and vegetables for dielectric property, while we explore the water content monitoring in vacuum freeze-drying by dielectric constant. This paper has studied the effect of high pulsed electrical field on fruits and vegetables for dielectric property. Apple and white turnip were selected as experimental materials, using 3532-50 LCR tester to measure impedance, con- ductivity, capacitance and dielectric constant of fruit and vegetables in the frequency range of 1× 102 - 1 ×106Hz. The ECM830 HPEF generator was applied to these samples. Then I measured the dielectric parameters of different HPEF pre- treatments on fruits and vegetables, and obtained the change rule of the dielectric properties based on the results. I ana- lyzed the action mechanism through the equivalent model of fruits and vegetables. It can be provided and the fruits and vegetables moisture content can be expressed batter through dielectric property.
出处
《农机化研究》
北大核心
2012年第11期138-140,共3页
Journal of Agricultural Mechanization Research
基金
国家自然科学基金项目(30771242)
关键词
果蔬
高压脉冲
电场预处理
介电特性
fruits and vegetables
high pulsed
electrical field pretreatment
dielectric properties
