Drying kinetics of carrot using an electric field combined with hot air. (Thai)

Abstract

The objective of this research was to study the drying kinetics of carrot using an electric field
combined with hot air. Experiments were performed under the following conditions: air temperature entering
drying chamber of 60, 70 and 80 ^oC and air velocity of 0.5, 0.7, and 1.0 m/s. The electric field in the dryer
was formed from two electrode plates which were placed in parallel with an electrode spacing of 10 cm. The
electric field intensity was in the range of 50 to 150 kV/m. The product for drying is a carrot slice with an
average diameter of 5 cm and thickness of 0.5 cm. Carrot drying was performed to reduce the moisture from
the initial moisture content of 760 % d.b. to the constant product weight. Experimental results showed that the
drying time was reduced when the air velocity and temperature were increased. The electric field resulted in a
shorter drying time which depended on the electric field intensity. The electric field intensity of 150 kV/m
gave the shortest drying time. The rate of energy consumption when using the electric field was 5-39 % lower
than without the electric field