The total drying times under 95 kPa vacuum pressure required to reach the final moisture content were 35, 25 and 22 min, respectively at 2.1, 2.8 and 3.5 kW power density levels (Fig. 3). Evidently the drying of edamames by VMD is much faster than by AD. The microwave drying time for edamames is reduced to 0.5 h equivalent to 5–15% of air drying time. Drying rate increased as the microwave power density is increased. The microwave output power had a crucial effect on the drying rate, which can be attributed to the acceleration of interior moisture migration and resultant increased surface water evaporation by higher microwave power.