The lab-scale microwave-vacuum dryer in which the
materials to be dried can be rotated in the cavity was
developed by the authors and described in detail elsewhere.[
10] The actual measured full power output of the
magnetron was 400 W. The microwave-vacuum dryer was
operated at 2.5 kPa (absolute pressure) and the rotation
speed of the turntable was 5 rpm.
For freeze drying, a laboratory-scale freeze dryer
(Model 6L, Labconco Instrument Company, Kansas City,
KS, USA) was used.