X-Ray Diffraction Analysis for Starch

Starch is a polysaccharide generated by plants as a form of energy storage. The combination of the two macromolecules amylose and amylopectin, in particular, results in the complicated structure of starch granules. The X-ray diffraction (XRD) analysis is one of the powerful nondestructive technologies utilized to characterize crystalline material and is helpful to explain the preferred crystalline orientation, phases, structure, and structural parameters like crystal defects, strain, grain size, and crystallinity. Using this technique, the starch's long-range crystalline order in relation to the arrangement of the double helices is determined. In X-ray diffraction, native starch exhibits three different crystalline polymorph types (A-, B-, and C-type), with C-type being a combination of A and B types. This chapter includes an overview of the diffraction theory of X-rays by crystals, structural characterization of different starches using X-ray diffraction, and sample preparation protocols utilized in X-ray diffraction analysis for various starches.