Polysaccharide structures and interactions in a lithium chloride/urea/water solvent

The molten salt hydrate, lithium chloride (LiC1)/urea/water has previously been shown to swell cellulose, but there has so far been no work done to explore its effect on other polysaccharides. In this paper we have investigated the solvent effects of LiC1/urea/water on four natural polysaccharides. Fenugreek gum and xyloglucan, which are both highly branched, were found to increase in viscosity in LiC1/urea/water relative to water, possibly due to the breakage of all intra-molecular associations whereas the viscosity of konjac glucomannan which is predominantly unbranched did not change. Locust bean gum (LBG) had a lower viscosity in LiCliurealwater compared to water due to the disruption of aggregates. Con focal microscopy showed that fenugreek gum and LBG are able to bind to cellulose in water, however, the conformational change of fenugreek gum in these solvent conditions inhibited it from binding to cellulose in LiCliurealwater whereas conformational change allowed xyloglucan to bind to cellulose in LiCliurealwater whilst it was unable to bind in water. Konjac glucomannan did not bind to cellulose in either solvent system. These results provide new insights into the impact of polysaccharide fine structure on conformational change in different solvent environments. Crown Copyright (C) 2016 Published by Elsevier Ltd. All rights reserved.