Effect of high pressure on the structure of potato starch

Potato starch-water suspension (10%) was subjected to high pressure treatment at 600 MPa for 2 and 3 min. Cross-polarization/magic angle spinning (CP/MAS) C-13 NMR spectra of the obtained starch preparations indicated distinct signal resonances at 81.23 and 82.46 ppm, respectively, which corresponded to amorphous sites (C-4) within starch structure. The Ft-i.r. analysis of starch preparations showed that high pressure significantly affected the intensity of bands corresponding to the amorphous (1018 cm(-1)) and more ordered (1047 cm(-1)) part of starch structure. The DSC analysis showed a decrease in gelatinization temperatures (T-o, T-p, T-c) upon high pressure treatment. A substantial decrease in the total enthalpy of pressurised starches along with the time of treatment was also found. The SEM analysis indicated that in the starch structure the granule's surface was the most resistant to high pressure treatment. The inner part of the granule was almost completely filled with gel-like network, with empty spaces growing in diameter towards the centre of the granule. (C) 2004 Elsevier Ltd. All rights reserved.