Different authors have investigated the change of apparent density of starchy materials during drying and found similar results (Marousis and Saravacos, 1990; Wang and Brennan, 1995; Yan et al.,2008). Shrinkage is responsible for the increased apparent density at low moisture contents. During the final stage of the drying the volume of the sample does not change with the further loss of water. Therefore, the apparent density of the sample decreases