Solution Structure of Molecular Associations Investigated Using NMR for Polysaccharides: Xanthan/Galactomannan Mixtures

Makoto Takemasa*, Katsuyoshi Nishinari

*この研究の対応する著者

    研究成果: Article査読

    13 被引用数 (Scopus)

    抄録

    Although the intermolecular nuclear Overhauser effect (NOE) signal was valuable to elucidate molecular association structure, it could not always be observed for associated molecules due to the short spin-spin relaxation time T2 in NMR measurements, especially for high molar mass systems. While almost no study has been reported for high molar mass polymers (>1 × 106), especially for polysaccharide-polysaccharide interactions, NOE signals were observed for the first time between two different types of polysaccharides, xanthan and galactomannan (locust bean gum), forming a synergistic gel, as a direct evidence of intermolecular binding of polysaccharides. The NOE peak was found between pyruvic acid in xanthan and anomeric proton of mannose of galactomannan. This NOE signal was observed only when mixing time >0.5 s, indicating indirect NOEs caused by spin diffusion. Therefore, this NOE could not be used to construct the molecular models. However, it is a direct evidence for the binding between two different types of polysaccharide to elucidate the synergistic gelation. This NOE signal was observed only for low molar mass galactomannans (1.4 × 104). T2 of pyruvate methyl drastically decreased at low temperatures in the presence of synergistic interaction, suggesting that pyruvate group at terminal end of side chain in xanthan plays an essential role in synergistic interaction. (Figure Presented).

    本文言語English
    ページ(範囲)3027-3037
    ページ数11
    ジャーナルJournal of Physical Chemistry B
    120
    12
    DOI
    出版ステータスPublished - 2016 3 31

    ASJC Scopus subject areas

    • 物理化学および理論化学
    • 材料化学
    • 表面、皮膜および薄膜

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