Energy efficiency of microwave drying
Fig. 8 shows the microwave specific energy consumption values at different amounts of microwave powers for the drying of sardine fish. Statistical analyses showed that microwave power in the range of 200–500 W was not significant on the specific energy consumption values of sardine fish (a = 0.05). However, it was noted that the lowest specific energy conoccurred in 500 W. Drying energy consumption at 500 W was 3.78 MJ/kg water. Rozainee and Ng (2010) reported that the energy consumption of convective hot air drying of 70 °C was 164.3 MJ/kg water, whereas microwave-hot dehydration with low (91 W), medium low (217 W) and med- ium (373 W) mode of microwave power coupled with hot air temperature of 70 °C required only 15.7, 33.0 and 27.7 MJ/ kg water, respectively.