微波泡沫干燥条件下浆果果浆干燥均匀性研究

The drying uniformity of dehydrated berry subjected to different microwave foam drying conditions

为提高微波泡沫干燥浆果果浆干燥均匀性,以树莓浆果为试验材料,选取微波强度、物料厚度和风速作为影响因素,树莓干品的含水率均匀度作为目标因素,分析干燥条件对微波泡沫干燥果浆干燥均匀性的影响,并模拟不同干燥条件下,微波泡沫干燥过程中起泡果浆内部微波能吸收情况及温度和水分分布规律,得出高均匀度的微波泡沫干燥浆果果浆工艺参数。结果表明,微波泡沫干燥条件(包括微波强度、物料厚度和风速)对浆果果浆干燥均匀性影响显著;在起泡果浆内部,微波能沿传递方向存在严重的衰减现象,导致果浆干燥速率下降,干燥均匀性差;得出高均匀度的微波泡沫干燥浆果果浆合适工艺参数为:微波强度12 W/g、物料厚度6mm、风速4 m/s。从调整干燥条件的角度提高微波泡沫干燥浆果果浆干燥均匀性,可获得品质均一的高品质浆果干品。

The aim of this study was to improve the drying uniformity of dehydrated berry obtained by applying microwave foam drying. Raspberry fruit was used as material. Microwave intensity, puree thickness and velocity of air were chosen as influencing factors, and the degree of uniformity of moisture in dehydrated berry was selected as objective factor. The effects of drying conditions on drying uniformity of dehydrated berry were evaluated. A computer simulation was established by using the COMSOL multiphysics software to simulate the distribution of microwave energy and the regularity of moisture and temperature in the raspberry puree and the reasonable parameters of perfect uniformity berry powder were put forward. The results showed that the uniformity of moisture in dehydrated raspberry was clearly influenced by microwave intensity, puree thickness and velocity of air. The uniformity of dehydrated raspberry was bad due to the difference of drying rate between different locational puree, because microwave attenuated seriously along its transfer direction. And the perfect uniformity of dehydrated puree could be obtained with microwave intensity of 12 W/g, puree thickness of 6 mm, velocity of air of 4 m/s, respectively. The outcome of this research provided a potential way to obtain excellent quality dehydrated berry subjected to microwave foam drying.