title: The new insight on ultrastructure of C-type starch granules revealed by acid hydrolysis.
abstract: C-type starch granule could be considered as the mixture of A- and B-polymorphs. The ultrastructure of C-type starch granules has not been elucidated detailedly by comparison with that of A- or B-type starch. To better understand the ultrastructure of C-type starch granules, Environment Scanning Electron Microscope (ESEM) and Field Emission Gun Transmission Electron Microscope (FEG-TEM) have been used to analyze the conformation and ultrastructure of C-type starch granule from Rhizoma Dioscorea during acid hydrolysis. SEM results showed that the amorphous areas were mainly located interior part of C-type starch granules whereas the crystalline regions were found mostly in the peripheral region of the granules. The grain size can be confirmed to be about 4.5-9 nm from the HR-TEM micrographs. The nanocrystals from acid-thinned starch displayed the typical face-centered cubic structure. This selected area electron diffraction patterns showed that individual C-type starch granule consisted of A- and B-type polymorphs.
authors.affiliation: School of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072, China.
authors.forename: Shujun
authors.initials: S
authors.lastname: Wang
authors.forename: Jinglin
authors.initials: J
authors.lastname: Yu
authors.forename: Fengmin
authors.initials: F
authors.lastname: Jin
authors.forename: Jiugao
authors.initials: J
authors.lastname: Yu
mesh_terms: D008854:Microscopy, Electron; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D013213:Starch / Q000737:chemistry / Q000648:ultrastructure*
chemical_list: D013213:Starch