2.2.3. Microwave-vacuum drying
A microwave vacuum oven (WZD1S; Nanjing Sanle Microwave
Technology Development Co. Ltd., Nanjing, China) with the function of
online weighing was used for the microwave vacuum drying process.
A schematic diagram of the microwave vacuum dryer is presented in
Fig. 1. Two hundred grams of the samples was single-tiled in the plate
and dried at optimized parameters (power: 800 W; vacuum pressure:
70 kPa) for different times to obtain samples with different water content,
and stored in vacuum bags for 24 h to ensure uniform moisture
content throughout the sample. One MVD experiment was performed
for each treatment (NOB, HWB, and MWB), and several samples from
each experiment were used for later tests.