In the present study, the effect of blanching and freeze-thaw pretreatment on the drying rate of carrots and the relationship between drying rate and the state of the cell membrane and cell wall and pectin methylesterase (PME) activity in the pretreated sample tissues were investigated. Summarizing the results, injury to the cell membrane and weak adhesion of cell walls due to the belimination reaction of the pectins greatly changed the permeability of the plant tissues and facilitated the drying rate. Also, the significantly large drying rate of the frozen-thawed samples was attributable to the formation of ice crystals that formed during freezing, facilitating water migration. The findings of this study may be important information for the development of new pretreatment conditions before drying of vegetables. In particular, the
results revealed that the freezing-thawing treatment before drying
is significantly effective to shorten the drying time. However, it is
not clear that the treatment is beneficial from the aspect of the total
energy cost consumed in the process and the quality of the dried
products, therefore, these points should be evaluated for future
work.