Porous starch granules are formed by the partial hydrolysis of starch using glucoamylases. These porous granules can be used to reveal structural information about the starch itself. Starches from four different sources were used as substrates in this study. These starches were partially hydrolyzed using glucoamylase. The material left behind after enzyme treatment was then treated to thermal analysis using TG and DSC to characterize the hydrolysis product. A structural analysis was made using SEM and powder X-ray diffraction to investigate whether the partial hydrolysis had any effect on the granule structure and the crystallinity of the different starches. In each case, except for potato starch, combustion in air took place at a lower temperature. On the other hand, the gelatinization temperature increased as the porosity increased.