Drying Characteristics of Asparagus Roots (Asparagus racemosus Wild.)

Abstract

This article presents the drying characteristics of asparagus roots of different shapes and sizes under blanched and nonblanched conditions using a hybrid solar dryer and mechanical tray dryer at three temperature levels of 50, 60, and 70°C. The drying rate increases with the increase in drying air temperature, and blanching also increases the drying rate. The drying rate also depends on shape and size of the asparagus roots. The highest drying rate was found for sliced samples followed by split and whole root samples. The drying rate was extremely low for the whole asparagus roots. Cream color of asparagus roots remained almost unchanged after drying but the brightness increased. The quality change of the dried products in terms of color change was not significant in the temperature range of 50 to 70°C. Five thin-layer drying models were fitted to the experimental data of blanched and sliced asparagus roots. The Page equation was found to be the best followed by Midilli et al.[ 33 ] The agreement between the predicted and experimental results was excellent.