Microwave drying and grinding characteristics of wheat (Triticum aestivum).

Wheat samples of approximately 20 g each were dried in a domestic microwave oven for different time periods ranging from 15 to
150 s with different moisture contents ranging from 0.11 to 0.23 kg of water/kg of dry weight of solids. The samples showed an
average moisture loss of 4.4–10:6 � 10�4 kg of water/kg of dry weight of solids per second. The dried samples were ground in a
domestic dry grinder, and the ground samples were subjected to sieve analysis to calculate the average final particle size. The
grinding characteristics were evaluated by calculating the Bond�s work index. The microwave dried samples for 120 s were crisp and
consumed less energy for grinding compared to the control samples. The same trend was maintained even when the wheat samples
were dried in bulk by taking 1 kg of sample (initial moisture content of 0.11 dry weight basis) and dried for 15 min. The Bond�s work
index for the bulk sample was 2.26 compared to 2.41 kWh kg�1 for the control of the equal moisture content. Studies were also
made on the effect of the microwave power supply on drying and grinding, and this was found to have effect on the latter. These
studies have all indicated that microwave drying of wheat samples before grinding helps reduce power consumption in due course in
wheat milling industries. The microwave drying did not change the total protein content, but there were some functional changes in
the protein which was evident from the gluten measurements.