In this study effects of acid hydrolysis, autoclaving and storage (95 degrees C for 2, 3, and 4 days) on resistant starch (RS) formation in corn starch were investigated and functional properties of RS preparations were determined. RVA peak and final viscosity values of the RS preparations decreased gradually for each storage period with increasing hydrolyzation level. RS contents increased to 13.6-16.7% as a result of storage. RS contents of the samples dried without storage were lower than those of the stored samples up to 3.5 h hydrolysis. Solubility and water binding values of RS preparations were higher than those of the native and hydrolysed samples. In contrast to RS preparations, the native and hydrolysed samples affected the emulsion properties of soy protein inversely.