1998 Fiscal Year Final Research Report Summary
Basic Study on Molecular Motion in Suplamolecules and Its Application by Field Gradient NMR and ESR.
| Project/Area Number |
09640717
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
分離・精製・検出法
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| Research Institution | Tokyo University of Fisheries |
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Principal Investigator |
WATANABE Tokuko Tokyo University of Fisheries・Department of Food Science and Technology, Professor, 水産学部, 教授 (40092382)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUKAWA Shingo Tokyo University of Fisheries・Department of Food Science and Technology, Assista, 水産学部, 助手 (30293096)
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| Project Period (FY) |
1997 – 1998
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| Keywords | Water / Polysaccharide / Sol-gel Transition / Field gradient NMR / Spin Probe ESR / Saturation Transfer EPR / Diffusion Coefficient / NMR Relaxation |
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| Research Abstract |
I Coil-Helix Transition and Sol-Gel Transition in Gellan / Cation / Water System
Cation dependence of both transitions has been studied by NMR relaxation time and molar ellipticity by CD.The transition temperature and a reversibility in the coil-helix transition showed cation dependence, in which KandCs ions differently affected from other alkali cations, For the sol-gel transition, divalent cation enhanced the gelation by forming crosslinks, while monovalent cation firstly contributed a shielding of anionic charge of gellan chain and then helped the gelation by hydrogen-bonding. Gelation mechanism was explained on the basis of the hydrogen bonding behavior of water which clearly appears in T_2 relaxation time.
II Gelation Mechanism in Dextran / Cation / Water System
Only K ion contributed to gelation of the neutral dextran polymer by potassium bonding, which was proved by K-NMR and water diffusibility. The selectivity for K ion is due to the ionic radius and hydration behavior of K ion :
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Na ion enhanced K/dextran gel structure and resulted thermal stability of the gel.
III Gel Formation Mechanism for Low-set and High-set Curdlan Gels
Gel formation process of the curdlan showed very complicated structural change of the chain. Water mobility and proton exchange reflected the change in details. Existence of three types of water in the gel matrix was proved by spin-probe ESR method in cooling and heating process.
IV Hydration Behavior in Pullulan Solution
High concentration of pullulan solution showed a stable hydration sphere around the polymer chain, where motional exchange of hydrated water molecules into bulk water was very slow. The specific hydration behavior in pullulan solution was investigated.
V Freezing and Thowing Process in Starch and Curdlan Gels
The process was monitored by spin-probe ESR method An amorphously freezing water molecules were detected and the amount of the water was estimated. Rotational correlation time was evaluated in super-cooled, unfrozen and frozen water molecules. Less
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