A laboratory microwave oven (M700, Guangdong Midea
Microwave Oven Co. Ltd., Guangdong, China) with a maximum
power output of 700W and 2455 MHz was used. The dimensions
of the microwave cavity were 105 140 445 mm. The samples
were spread in a single layer on a glassy culture dish, and dried
at 539W of the microwave power. Drying lasted for 18 min until
the sample moisture fell below13% (wet basis).