Abstract: Studying starch granular structure is the basis for starch modification and extended scope of application. In the present work, the effect of high hydrostatic pressure (HHP) treatment on the granular structure of sweet potato starch was investigated by scanning electron microscope, X-ray diffraction, differential scanning calorimetry, Fourier infrared transform spectroscopy and rapid visco analysis. The results showed that surface morphology of starch granules was not significant changed after treatment at 200–500 MPa. When the pressure increased up to 600 MPa, the starch granules began to collapse and coagulate, thereby losing birefringences; the peak viscosity, trough viscosity and final viscosity were enhanced by 9.15%, 27.18% and 20.21% (P < 0.05), respectively; and the pasting temperature and peak time were increased by 1.9 ℃ and 1.16 min, while the pasting enthalpy and breakdown viscosity were decreased by 46.18% and 66.46% (P < 0.05). In addition, the crystal type and molecular groups of sweet potato starch remained unchanged after HHP treatment.

Key words: sweet potato starch, high hydrostatic pressure treatment, granular structure