Effect of dual modification with ultrasonic and electric field on potato starch.

Applying high voltage electric fields to starch is a novel method. Very limited studies were done on high ultrasonic power. Native potato starch (NPS) was modified by ultrasonic (US), electric field (ES) and a combination of the two treatments: ultrasonic prior to the electric field (UES), electric field prior to the ultrasonic (EUS) and ultrasonic and electric field at the same time (UAES). Physicochemical properties, texture profile property and in vitro digestibility of potato starch were characterized. Compared to the NPS single and dual-modified potato starch granules displayed deep pitting on the surface and their shape was deformed. X-ray diffraction results suggested that the characteristic peaks were not changed, whereas the relative crystallinity increased for all treatments except for the ES treatment. The ES granule also showed a relatively high average size distribution. The UES showed a lower level of conclusion temperature and resistant starch content (10.56%). The EUS exhibited the most desirable properties such as high light transmission, high water absorption capacity, solubility (77.50%), swelling power (50.48%) and resistant starch content (79.98%).