Influence of pre-treatments on the drying kinetics during vacuum drying of carrot and pumpkin

Vacuum drying of carrot and pumpkin were carried out to compare the influence of freezing and blanching as pre-treatments on the drying kinetics at temperatures of 50, 60 and 70 °C and vacuum chamber of 5 and 15 kPa. The experimental curves of drying were adjusted to the diffusional model of Fick for an infinite slab. The results, provide evidence that pre-drying pre-treatments affect moisture transport of this products. It was found that the values obtained for the samples pumpkin presented larger values of the diffusion coefficient than the samples carrots.