Commercial corn starch or degermed corn contains lipids and protein, and starch-lipid (or protein) complexes were formed during extrusion. The formation of starch and lipid (or protein) complexes was investigated using the complex index (CI) and differential scanning calorimetry (DSC) analysis. The CI of extrudates of a commercial corn starch/germ mixture (or gluten meal) showed that starch was complexed with lipid or protein, thus decreasing the iodine-binding capacity of amylose. The CI increased as the content of germ or gluten meal blending starch increased. Blends containing degermed corn and thermostable or mesophilic α-amylase were extruded. The CI of extrudates was higher than 55%; however, the starch-lipid complex was not stable and could be separate d. The DSC analysis of the blending starch extrudate and palmitic acid showed that the enthalpy of the starch-palmitic acid complex was increased with increasing fatty acid content. Increased complex formation required more DSC heating, resulting in an enthalpy change of the endothermic peak rise, with the peak temperature higher than 100℃.