Thermal properties of polysaccharides at low moisture: 1—An endothermic melting process and water-carbohydrate interactions

Appelqvist, Ingrid A.M., Cooke, David, Gidley, Michael J. and Lane, Sally J. (1993) Thermal properties of polysaccharides at low moisture: 1—An endothermic melting process and water-carbohydrate interactions. Carbohydrate Polymers, 20 4: 291-299. doi:10.1016/0144-8617(93)90102-A


Author Appelqvist, Ingrid A.M.
Cooke, David
Gidley, Michael J.
Lane, Sally J.
Title Thermal properties of polysaccharides at low moisture: 1—An endothermic melting process and water-carbohydrate interactions
Journal name Carbohydrate Polymers   Check publisher's open access policy
ISSN 0144-8617
1879-1344
Publication date 1993-01-01
Sub-type Article (original research)
DOI 10.1016/0144-8617(93)90102-A
Volume 20
Issue 4
Start page 291
End page 299
Total pages 9
Place of publication Oxford, United Kingdom
Publisher Pergamon
Language eng
Abstract The thermal properties of a broad range of polysaccharides containing 5-25% w/w water have been studied by differential scanning calorimetry and dynamic mechanical thermal analysis (DMTA). Following room temperature conditioning, an endothermic event accompanied by material softening is observed at 45-80°C for all samples except those above their glass transition temperature. The temperature of the event is determined by thermal history and is apparently independent of polymer type or moisture content. The associated enthalpy increases with water content. Variable frequency DMTA analysis suggests a structural melting event rather than a relaxation process. The endothermic event is recovered over the days timescale after heating, and can be annealed to higher temperatures with increasing holding temperature. Results are interpreted in terms of a dynamic hydration model in which specific energetic water-carbohydrate interactions occur but with a lifetime defined by their local effective microviscosity. The observation of the endotherm below glass transition temperatures suggests that in aqueous polysaccharide glasses, enthalpic structures involving the solvent can be made and broken.
Keyword Enthalpy relaxation
Glass transition
Prior history
Polymers
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: Centre for Nutrition and Food Sciences Publications
 
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Created: Thu, 17 Mar 2011, 06:30:07 EST