The experiments on vegetables and industrial plant drying by microwave energy

In this work, the drying of red pepper, spinach and tea leaves were investigated in a combined microwave?fan assisted convection oven. Spinach and tea leaves, red pepper were dried by using microwave, microwave-fan combination and fan drying. The effects of microwave power drying (180, 360, 540, 720 and 900W), combining of microwave power (constant 180 and 540 W) and fan (100, 180, 230ºC) drying and only fan drying (100, 180, 230ºC) on drying time, drying ratio, color changing and energy consumption of spinach and tea leaves, red pepper have been investigated.A laboratory dryer is used for processes and moisture content at any drying time were compared by Newton, Page, Modified Page, Henderson and Pabis, Logarithmic, Wang and Singh, Diffusion Approach, Verma, Two Term Exponential, Simplifed Fick?s Diffusion, Midilli-Kucuk Equation Models. The performances of these models were compared according to the coefficient of determination (R2), standard error of estimate (SEE) and residual sum of square (RSS), between the observed and predicted moisture ratios. It was found that the Midilli-Kucuk model described the drying ratio satisfactorily in all drying methods.