远红外真空干燥白萝卜的实验研究

Experimental study of the far-infrared and vacuum dry of turnip

针对现有干燥设备存在的干燥效率低,难以满足高水分物料快速干燥等缺陷问题。利用自行改进的低温真空远红外干燥实验设备采用二次通用旋转组合的实验设计方法,探讨真空度、干燥温度、物料厚度对白萝卜干燥时间、复水率和Vc质量比的影响规律。所得实验数据采用目标函数法进行优化,并对结果进行扫描电镜(SESM)分析。优化结果为干燥温度70℃、真空度3000 Pa、物料厚度7 mm,在此干燥条件下物料各项指标最优,细胞组织保存率达到80%以上,能够真实地反映样品的组织结构原貌。脱水速率(RA)达到25.23 g/m2·h,复水比(RF)达到3.95,Vc质量比可达2.05 mg/g。该研究为远红外真空干燥技术应用于高水分物料快速干燥提供了理论依据。

Aiming at the defective problem of conventional drying equipment whose drying efficiency is lower and cannot satisfy the rapid drying of high moisture materials, the far-infrared cryogenic vacuum drying equipment that was self improved was utilized and the quadratic general rotary unitized design approach was adopted in this paper. The influence law of vacuum degree, drying temperature, material thickness on drying time, rehydration rate and Vc mass ratio of the turnip were investigated. The objective function method was adopted to optimize obtained experimental data and scanning electron microscopy was used to analysis the results. When the drying temperature was 70 ~C, the vacuum degree was 3000 Pa, and the material thickness was 7 mm, the indicators of material were optimal. At this time, the cell tissue preservation rate was up to 80%, and the original organizational structure of the samples could be truly reflected. The dehydration rate （RA） reached 25.23 g/m2· h, the rehydration ratio （RF） reached 3.95, and the Vc mass ratio reached 2.05 mg/g. This study may provide a theoretical basis for the far-infrared vacuum drying technology applying to the rapid drying of high moisture materials.