An Investigation of the Variations of Drying Rate, Effective Diffusion Coefficient, and Activation Energy for Microwave-vacuum Drying of Cherry



Drying behavior, and the effect of different drying conditions (4 levels of microwave power, namely: 360, 600, 840, and 1200 watts along with 4 vacuum pressure levels of 200, 400, 600, and 800 mba) upon the traits of: "tendency to lose moisture", "effective moisture diffusion coefficient" as well as "activation energy rates" in the process of cherry drying were assessed. A microwave vacuum dryer set was employed to carry out the experiments. Results indicated a range of 3.21×10-9 to 20.005×10-9 m2/sec for the effective coefficient of moisture diffusion in cherry. Activation energy was calculated by use of an exponential relationship based upon Arhineus', for which the maximum and minimum values were found out as 23.91 and 21.23 watt/gr respectively. The activation energy figures for cherry, found by use of the microwave vacuum set at different levels of power and vacuum were very close to each other in 3 different methods of measurement