The Evaluation of Quality Parameters and Drying Efficiency of Button Mushroom in Hybrid Microwave-Hot Air Dryer

In this study, the button mushroom (agaricus bisporus) as a whole in a combined microwave-hot air dryer in two status of power density: fixed and variable, three levels of initial power density (1.5, 2 and 2.5 W/g) and three levels of hot air temperature (23, 50 and 70 ºC) were dried. Drying efficiency and the final dried product quality (color and rehydration ratio) were evaluated. The highest drying efficiency (44.44%) was obtained with 1.5 fixed power density and 23 °C. The results of color parameters showed that the dried product in constant power density status had better appearance (color) than the variable mode and also increased power density levels and reduced the air temperature increased the color changes and decreased final products quality. Also the dried product with constant power density in compared with variable power density and using the hot air in compared with environmental air had higher rehydration ratio.