3.2.2. Effect of water activity on dielectric properties
The dielectric properties of A. bisporus samples as a function of water
activity with the various blanching methods are shown in Fig. 5. The ε′
of all three samples varied with the water activity. Specifically, it
increased slowly at activities of 0.48–0.80, and then increased sharply;
in particular, the increase observed for the MWB sample was more
acute than that observed for other samples. The ε″ value increased
with increasing water activity in all three samples (Fig. 5); for example,
the ε″ value of the MWB sample increased from 3.58 to 18.47 as the
water activity increased from 0.43 to 0.90. A similar variation in ε″
withwater activitywas observed in theNOB andHWB samples. However,
in the same water activity range (aw) (0.4 b aw b 0.90), the MWB
sample had the highest ε″, followed byHWB and then NOB. The trendsdescribed above may have resulted fromthe effect of the ionic distribution
on dielectric properties, particularly ε″.