EFFECT OF HYDROTHERMAL TREATMENT ON THE GELATINIZATION PROPERTIES OF POTATO STARCH AS MEASURED BY DIFFERENTIAL SCANNING CALORIMETRY

Gelatinisation temperatures as a function of moisture content were det ermined for potato starch. The native starch was then hydrothermally t reated at a temperature 3% (Kelvin degrees) below the gelatinisation p eak temperature and at moisture levels varying from 20 to 67% (by weig ht). Gelatinisation temperatures, temperature ranges and enthalpy valu es were affected for all treated samples. However, two sample populati ons could be distinguished: those samples treated under 'limited' mois ture conditions and other samples treated in the presence of 'extra-gr anular' moisture. A two-step hydrothermal treatment further increased the gelatinisation temperature, but the effect of the second step was small in comparison to that of the first.