Carrots (Daucus carota L. subsp. sativus) are one of the most
widely cultivated and consumed vegetables throughout the world
[1–3]. In recent years, the consumption of carrot and its related
products has increased steadily based on their higher concentration
of carotene compared to other foods [1–3]. Carrots are a
high-moisture food with moisture content of 90 g/100 g on a wet
basis [2]. The dehydration of carrots seems to be a convenient
alternative for long-term storage or usage. Dried carrots are used
as an ingredient in various food products, such as soups, sauces,
ready-meals as well as healthy snacks [4,5]. The high content of
carotene is a unique property that makes dried carrot slices an
excellent candidate for developing oil free, healthy snack foods.
However, the nutritional value must be well preserved and a
puffed texture should be generated in the drying process.
Dehydration, or drying, involves transient heat and mass transfer
accompanied by physical, chemical, and phase change transformations.
Unfortunately, these transformations may cause changes
in the product’s quality as well as the mechanisms of heat and
mass transfer [6]. Presently, drying with hot air is the most widely
used method. However, long drying times and overheating of surface
during hot air drying consequently result in color darkening,
loss of flavor, and decrease in rehydration ability [7]. Freeze drying