Effect of microwave energy on dehydration of celery leaves

Celery leaves were dried in a microwave oven to determine the effects of microwave output power on drying rate, specific energy consumption, drying efficiency, leaves surface area and the color of dried product. Five different microwave output powers ranging from 180 to 900 W were used in the drying experiments. As the drying progressed, the loss of moisture caused a decrease in absorbing microwave power and resulted in a fall in the drying rate. Rising microwave power could reduce the rate of energy efficiency from 45.0% to 11.4% and growth of specific energy consumption from 5.3 to 18.7 MJ kg-1 water. Significant differences (p<0.01) were observed between the color’s variables of leaf in five microwave powers, but changing of color in microwave drying were less than oven drying