Figure 6 shows the experimental and simulated temperature time histories of peanut kernels with three moisture contents
of 10%, 20%, and 30% w.b. when subjected to RF heating for 4 min with electrode gap of 120 mm. With the measured
dielectric properties, the simulation results agreed well with the experimental data at three sections under three moisture
levels. Both the simulated and experimental results revealed that the sample temperatures increased almost linearly with
the RF heating time but the heating rates of peanut kernels were in the following order: 20% > 30% > 10% w.b. These
observed phenomena were similar to those found by Huang et al. (2015), in which the increasing loss factor caused an
initial increase and then a decrease in RF heating rates. The maximum heating rate can be obtained when ε 00 ¼ ε 0 þ dm/d0 (dm is the height of the sample, d0 is the air gap between the top electrode and the upper surface of materials) (Jiao, Tang, Wang, & Koral, 2014). In this study, the maximum RF heating rate would be achieved when the moisture content of the sample was conditioned to 20.4% w.b. based on the measured dielectric properties at 45 C.