Characterization of nanoscale retrograded starch prepared by a sonochemical method

摘要

Nanoscale retrograded starch (RS III) particles were prepared using high-intensity ultra-sonication combined with water-in-oil (w/o) miniemulsion cross-linking technique. Results showed that ultrasonication effectively fragmented RS III to nanoparticles 600-700nm in size. Scanning electron microscopy images showed that ultrasonic treatment produced notches and grooves on the surface of nanoscale RS III. X-ray diffraction analysis indicated that ultrasonication destroyed the crystalline structure of the clustered amylopectin and apparently led to amorphous, or low-crystallinity nanoscale RS III. Differential scanning calorimetry results showed that nanoscale RS III exhibited lower DH values, which indicated the lower stability of the crystals. Fourier transform infrared spectra showed two new peaks at 1532.30 and 1450.40 cm(-1). The new peak at 1532.30 cm(-1) can be considered the most satisfying evidence of the crosslinking reaction between starch molecule and MBAA. The new peak at 1450.40 cm(-1) resulted from the opening of starch chains by alkali. Thus, ultrasonication increased the amylose content and decreased the RS contents with weakened swelling power. In vitro studies showed that nanoscale RS III retained its antidigestibility property, so it could be used as a drug-carrier material. The drug-absorption properties of nanoscale RS III improved, and the adsorption kinetics described the contact time on the adsorption of captopril onto nanoscale RS III.