The toughening method of dielectric starch was investigated. The effects of microwave (MW) and radio frequency (RF) heating conditions on the morphology, microstructure, thermal characteristics, viscosity characteristics, and particle size distribution of potato starch were compared and analyzed. Results indicated that RF heating made the starch surface roughened and gelatinized. The X-ray diffraction pattern was not changed after dielectric heating, but the crystallinity was reduced compared to the unheated potato starch. Potato starches had a greater volume diameter after RF heating than after MW heating. Compared to unheated potato starch, gelatinization enthalpy (ΔH), onset temperature (To), peak temperature (Tp), and conclusion temperature (Tc) of starch under dielectric heating decreased significantly. In contrast, the breakdown value and peak viscosity of unheated potato starch were greater than that of the dielectric heating starches. The swelling power degree of the MW-heated starches was greater than RF heated. Dielectric heating starches exhibited lower transmittance values than unheated potato starch during the duration of storage.
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