姜浆物料折射窗薄层干燥特性

Drying characteristics of ginger puree with refractance window drying method

为探索一种不宜进行喷雾干燥的热敏性浆料物质的干燥方式,利用折射窗(Refractance window)干燥对姜浆物料的干燥特性进行研究。结果表明,在75～95℃下干燥,物料温度变化曲线显示其在干燥开始时迅速上升至60～75℃,之后随干燥时间渐趋平缓。物料温度始终比干燥热源温度低,温差在15～25℃之间。在相同的干燥温度和风速下,不同薄层厚度物料的温度差异不明显。提高风速可以降低物料的温度。在较高干燥温度下没有观察到典型的恒速干燥阶段。干燥强度和样品最终含水率分别随着物料薄层厚度的减小,干燥温度提高和风速的增大而增大和降低。该研究为Refractance window干燥技术应用于浆液状物料的薄层干燥作出了探索。

To evaluate the adaptability of a thin-layer drying processing for liquid materials which cannot be dried with spray drying or that are heat sensitive, drying characteristics of ginger puree with refractance window method were investigated in the present study. The results showed that the temperature of ginger puree dried with refractance window at the range of 75 to 95℃ rapidly reached 60-70℃ at the initial drying period. Then it kept a slow changing trend at the later stage. But the temperature of the product was always lower than that the heated water, with a temperature range of 15 to 25℃. The temperature curve of ginger puree with 1-3 mm of thickness showed a similar trend at the same drying temperature and air velocity. The temperature of the product could be decreased through increasing the air velocity. The constant drying strength was not found when dried with higher temperature. The drying strength went up and the final moisture content of the product decreased respectively with thinner thickness of ginger puree, higher temperature or higher air velocity. The current findings show the potential of refractance window method for drying of liquid or puree materials.