Influence of infrared drying on the drying kinetics, bioactive compounds and flavor of Cordyceps militaris

The influences of different infrared drying conditions on drying kinetics, bioactive compounds and flavor of Cordyceps militaris were evaluated. The results indicated that as the drying temperature and air velocity increased, the total drying time and final water activity of Cordyceps militaris were reduced. Drying at 50, 60 and 70 degrees C reduced 30, 40 and 60% of the drying time compared to that of 40 degrees C, respectively. However, the glass transition temperature showed the opposite trend. Namely, a higher drying temperature favors the storage of dry products. Drying at 40 degrees C is beneficial to the retention of color and volatile compounds. For non-volatile flavor, relatively high drying temperature was more effective in reducing bitterness and bitter aftertaste. The best condition to retain the adenosine, cordycepin, total phenolics, and nutrients (Cu, Fe, Zn and Mn) in Cordyceps militaris is drying at a flow rate of 1 m s(-1) at 60 degrees C.