荔枝常压与减压干燥过程的试验研究

Experiment and Research on Lychee Drying Under Atmosphere and Decompression

在干燥介质相对湿度基本不变和不同的温度条件下，考察了荔枝整果和果皮、果肉、果核各部分在常压和减压下的干燥特性及干燥过程中果内温度的变化特性。查明了果膜对果肉及果核中水分向果壳迁移的抑制力很强；减压干燥虽有利于果皮中的水分扩散，但并不能有效地促使荔枝果肉及果核中水分向外迁移；在整个干燥过程中，整果内的温度上升速度比较缓慢。

The changes of inner temperature and drying characteristics for rind, flesh and stone of lychee were investigated under constant relative humidity of drying medium at different temperatures, and at atmosphere and decompression. Results show that the membrane resists moisture moving from the flesh or stone to rind. Decompression drying is helpful to the diffusion of the moisture inside the rind, but it is not so efficient to move the moisture out from the flesh or the stone. In the drying process, the inner temperature rising of lychee is slow. A proposal on appropriate drying technique for lychee is given based on the experiments.