title: Thermal expansion behavior of A- and B-type amylose crystals in the low-temperature region.
abstract: The thermal expansion behaviors of A-type and B-type amylose crystals, which were prepared by recrystallization of short amylose chains synthesized by phosphorylase, were investigated using synchrotron X-ray powder diffraction between 100 and 300K. For both types of crystals, the room-temperature phase (RT phase), which is the usually observed phase, transitioned to a low-temperature phase (LT phase), on cooling. The phase transitions took place reversibly with rapid changes in the unit-cell parameters around 200-270K. The differences between the RT and LT phase were investigated using solid-state (13)C NMR spectroscopy, which revealed there were changes in molecular chain conformations. These results suggest that the phase transition of water molecules on the crystalline surfaces affects the thermal behavior and structure of polysaccharide crystals.
authors.affiliation: Research Institute for Sustainable Humonosphere, Kyoto University, Gokasho, Uji, Kyoto 811-0011, Japan. Electronic address: kayoko_kobayashi@rish.kyoto-u.ac.jp.
authors.forename: Kayoko
authors.initials: K
authors.lastname: Kobayashi
authors.affiliation: Department of Biomaterials Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan; Department of Plant & Environmental New Resources, College of Life Sciences, Kyung Hee University, 1, Seocheon-dong, Giheung-ku, Yongin-si, Gyeonggi-do 446-701, Republic of Korea.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kimura
authors.affiliation: Department of Biomaterials Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan.
authors.forename: Philip-Kunio
authors.initials: PK
authors.lastname: Naito
authors.affiliation: Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki 305-8687, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Togawa
authors.affiliation: Division of Forest and Biomaterials Science, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan; Department of Plant & Environmental New Resources, College of Life Sciences, Kyung Hee University, 1, Seocheon-dong, Giheung-ku, Yongin-si, Gyeonggi-do 446-701, Republic of Korea. Electronic address: wadam@kais.kyoto-u.ac.jp.
authors.forename: Masahisa
authors.initials: M
authors.lastname: Wada
mesh_terms: D000688:Amylose / Q000138:chemical synthesis* / Q000737:chemistry; D066241:Carbon-13 Magnetic Resonance Spectroscopy; D003080:Cold Temperature; D003460:Crystallization; D008855:Microscopy, Electron, Scanning; D017356:Synchrotrons; D014961:X-Ray Diffraction
chemical_list: D000688:Amylose
keywords: Amylose; Solid-state (13)C NMR; Synchrotron X-ray powder diffraction; Thermal expansion