New RS preparations were obtained by physical modification of potato, tapioca, maize and wheat starches and they contained respectively 30.84%; 18.34%; 25.48% and 26.34% RS determined according to the Champ method. Starch samples were investigated using the Brabender rheological method, X-ray diffractometry and light and scanning electron microscopy. It was found that all RS preparations showed lower gelatinisation temperature as compared to native ones. The light microscopy study however proved that RS preparations are more difficult to disperse in water than native starches. It was observed that the dispersion process depends on the amylose content in starch. The scanning electron microscopy study showed that the forms of preparations were similar to those of pregelatinised starches (drum dried or extruded). The X-ray diffraction studies showed that all preparations obtained from both tuber and cereal starches showed a B-type X-ray diffraction pattern characteristic of native tuber starches.