Under all the drying conditions used herein, the drying rate was
higher for the freezing pretreated carrots than for the untreated
counterparts. This may be because the freezing process breaks open
the cell wall of the carrot, allowing easy transfer of the water in the
materials (Arolde and Fernanda, 2007). For the hot-air fluidized
bed, the drying ratewas greater at 12 kPa than at 101 kPa. At 12 kPa,
shrinkage of the carrot sample, induced by the drying process, was
reduced with freezing pretreatment (as shown in Fig. 5); this
means that the porosity of the carrot sample subjected to freezing
pretreatment was larger at 12 kPa. Therefore, the liquid water and
steamin the inner part of the carrot can move more easily at 12 kPa
than at 101 kPa.