Li et al. (2010a)reported this phenomenon for the same strategy in apple MW drying by measuring sample temperature.
In their study, they reported that product charring often occurs during the closing period when the temperature reached an undesirably high value.
The results of this study were similar to previously reported results (Andrés et al., 2004; Bilbao-Sáinz et al., 2005; Feng and Tang, 1998)