a b s t r a c t
A drying method with a low drying temperature and a high drying rate that induces small volume
change in biological samples was developed for drying heat-sensitive foods and agricultural products.
Freezing pretreatment was combined with fluidized-bed drying under reduced pressure. Cylindrical
carrot samples were frozen and then immersed in a fluidized bed of inert particles under reduced
pressure without thawing. A higher drying rate was achieved for carrots subjected to freezing pretreatment
than for the untreated counterparts. The drying rate was higher at 12 kPa than at atmospheric
pressure. The volume change induced during the drying process was smaller for carrots subjected to
freezing pretreatment than for the untreated congeners. A high drying rate at a low temperature with
minimal sample shrinkage was achieved via the combined freezing pretreatment and fluidized-bed
drying under reduced pressure. This method can be applied for drying heat-sensitive materials such
as food and agricultural products.