The ε″ value for the MWB sample decreased from 22 to 1.58 with
decreasing moisture content from 9.45 (d.b.) to 0.37 (d.b.), possibly
because of water binding and the increased restriction of the mobility
of polar water molecules (enclosed by the structure) at a lower water
content, which promoted a rapid decrease in ε″. In comparison with
the phase at which the moisture content dropped further below 2.27
(d.b.), the ε″ in the phase at which the moisture content ranged
between 2.27 (d.b.) and 9.52 (d.b.) was lower. This finding suggests
that microwaves could be used to dry A. bisporus effectively at the initial
stages of drying when the moisture content is higher than 2.27 (d.b.).
The variation in ε″ among the three sampleswas similar to the dielectric
behavior reported previously in garlic (Fig. 4) (Sharma & Prasad, 2002).