Wheat starch (lipid content 0.54%) was defatted with different solvents (80% methanol, 80% methanol followed by petroleum ether, water-saturated butanol, water-saturated butanol followed by methanol, or petroleum ether, 70% propanol) and, subsequently, autoclaved and cooled to form resistant starch (RS). Defatting increased RS yields. This effect was much more pronounced than was predicted from calculations of the amount of complexed amylose; thus, the amylose zones complexed with ligands are not the only ones prevented from participating in the retrogradation process. When sodium dodecyl sulfate (SDS) was added to defatted wheat or amylomaize VII starch, RS yields decreased substantially. X-ray diffraction and differential scanning calorimetry showed that amylose-lipid complexes had formed in the presence of both endogenous and added lipids (SDS). Thus, less amylose was available for interactions leading to the formation of double helices and RS. Adding SDS to the starch also caused a difference in RS quality. Changes in polymorphism (more A-type characteristics) and in the melting enthalpy of the isolated RS could be detected by X-ray diffraction and differential scanning calorimetry, respectively.