  The x-ray diffraction (XRD) patterns reported for starch in the literature
describes it as a semicrystalline polymer that indicates that amorphous and
crystalline regions form it, and this is commonly accepted. However, these
patterns have not been well interpreted according to the XRD theory, and the
crystal size effect has been neglected. A simulation of the effect of the
crystal size on the shape and width on XRD patterns for A-type (orthorhombic
structure, ICDD card No. 00-043-1858) using PDF-4 software shows that the
patterns of starches are governed by the elastic and inelastic scattering
producing wide peaks. For isolated starches XRD patterns, the separation of
inelastic and elastic scattering is not possible, then the calculation of the
crystalline percent or crystalline quality does not make any physics sense.
