热烫藕条微波滚动干燥热场分布及脱水品质

为解决微波干燥不均问题,提升藕条的干燥品质,作者以热风干燥(Hot-Airflow Drying,AD)为对照,利用自主研制的微波热风滚动床干燥(Microwave Hot-Airflow Rolling-Bed Drying,MARD)装备,研究了沸水漂烫和未漂烫下藕条在MARD不同干燥阶段的热像分布,以及"干基水分质量分数-干燥时间"变化曲线,分析了不同工艺下物料的感官品质和微观结构。结果表明:藕条MARD过程在热风和微波的协同作用下温度逐渐升高,最终稳定在设定范围。沸水漂烫减少MARD干燥时间10～15 min,对MARD过程热像分布影响不显著。沸水漂烫会使脱水藕条的色泽变暗,沸水漂烫和微波干燥过程都会破坏藕条的微观结构。

Temperature-Field Distribution and Dehydrated Quality of Lotus-Root Sticks during Microwave Rolling-Bed Drying

In order to solve the problem of non-uniform drying during microwave drying and improve the drying quality of lotus root, a microwave hot-air flow rolling-bed drying (MARD) device was developed by our team. The hot-air flow drying (AD) was used as a control, and the thermal image distribution of lotus root with boiling-water blanching and non-blanching at different drying stages of MARD and the dry-basis water contents were studied. The sensory quality and micro-morphology of materials in different processes were investigated. As a result, with hot air and microwave, the temperature of lotus-root sticks was gradually increased, and finally stabilized within a set range during MARD. Boiling-water blanching reduced the drying time of MARD by 10-15 minutes, but had no significant effect on the temperature distribution of the materials during MARD. Boiling-water blanching darkeddehydrated lotus root, and both boiling water blanching and microwave drying destroyed the microstructure of lotus-root sticks.