Microwave dryer energy analysis with ohmic and blanching pretreatments in drying carrots

In this research, carrots were first cut into equal pieces and then subjected to different treatments at different levels. The voltage levels were at 40, 60 and 80 volt in ohmic pretreatment and at 3, 5, and 7 minutes. The parameters studied in the blanching pretreatment included time, with different levels of 5, 10, and 15 minutes. Immediately after pretreatment, samples were dried in microwaves at 360, 600 and 900 watts. Finally, for each case of microwave dried and pretreated samples and their different levels, the energy efficiency values and their lost energy were calculated. According to the results, in the majority of cases, we see that increasing the amount of microwave power increases the energy efficiency, and subsequently, the lost energy decreases, so that the maximum value was 15.8797%. In the study of the effect of voltage in the ohmic pretreatment, a similar result was obtained, with the highest energy efficiency of 15.7061%. Also, in evaluating the effect of time parameter in ohmic pretreatments, it was observed that with increasing pretreatment time, the amount of energy efficiency was also increased and the energy lost was reduced, so that the highest amount of energy efficiency and the lowest amount of energy lost were respectively 15.7409% and 8.2358 MJ were measured.