The fine structure of amylopectin differs significantly from the structure of glycogen. Amylopectin has a unit structure designated as a cluster, whereas glycogen exhibits no such structure because the α-1,6 branch points in glycogen are randomly distributed. Amylopectin clusters are interconnected by long chains that span across two or three clusters. The short and intermediate chains within a single cluster are called nonbranched chains or branched chains (Jane et al., 1997;Peat et al., 1956).Starch is a vital source of energy that helps sustain human life.Starch that stores nutritive energy in plant roots, tubers, or endosperms such as potato, tapioca, corn, and rice primarily comprises of carbohydrates in the form of polysaccharides. On the micrometer scale, starch granules ∼1-100 µm in size have a growth-ring structure composed of alternately arranged semicrystalline and amorphous shells. The semicrystalline shells are composed primarily of branched-chain amylopectin clusters, in contrast to the amorphous shells, which contain long linear-chain amylose and low-molecularmass amylopectin. On the nanometer scale, each semicrystalline shell consists of lamellae of alternating crystalline and amorphous layers, with a typical lamellar spacing of ~9 nm (also known as the 9-nm repeat structure), with crystallinity ranging from 15% to 45%.At the atomic level, the packing of the crystal structure of starch can be classified as either monoclinic (A-type) or hexagonal (B-type)