Analysis of the experimental data shows that
onion drying occurs only in the falling rate
zone. Drying rate can be defined as moisture
content on dry basis in unit of time. Drying
rate decreases with time in four experimental
temperatures, a result of the decrease in
moisture content as time passes (Fig. 1). An
increase in operational temperature in a
certain time, leads to a decrease in the
moisture content of the samples since the
evaporation rate increases with increasing
temperature (Fig. 2)