ABSTRACT
The quality of dried products generally depends on color, texture, taste, porosity, and other physical properties such as density and the specific volume. The change of quality attributes during drying strongly depends on process time and the applied drying conditions. The color of apples, as with other plant tissues, changes during drying and subsequent storage due to browning reactions. The drying curve provides valuable information about the drying behavior of a specific product and is used as a design basis for drying plants. The term "pseudo wet-bulb temperature" was first introduced by A. H. Nissan to describe the developing constant temperature value of wet porous textile bobbins that represents the equilibrium between heat exchange and moisture transport and that is similar to wet-bulb temperature but at later stages of drying. The pseudo wet-bulb temperature is heavily dependent on drying conditions and increases with increasing air temperatures.
