The heat-up time, energy cost and % solid in inulin extract of different extraction methods are shown in table 1. It appeared that the maximum energy cost occurred in conventional method while the minimum value was found in ohmic extraction by 200 V. It should be due to the indirect heating concept of conventional method that applied hot plate stirrer. It relied on heat conduction from the hot plate to the sample container and then heat convection from the internal surface of container to the JAT sample solution. On the other hand, the ohmic heating relied on the directly internal heat generation. The ohmic method could clearly raise the solid percentage in inulin extract, similar results to those in the Patiwit et al. (2015) study the core temperature profiles of black rice bran during ohmic heating and steaming treatments. The result indicated that ohmic heating method, the rising electrical voltage levels from 50 to 200 V caused the increasing temperature of the bran and the ohmic heating method gave a higher yield of colourant powder than that obtained by steam-assisted solvent extraction methods especially in case of applying ultrasonic before ohmic heating. It should be due to the cavitation effect of electricity and ultrasonic during inulin extraction. This finding is significant because ultrasonic affected on cell walls of plant in the solution showing that ultrasonic has the potential to raise the efficiency of extraction process (Lingyun et al., 2007).