- Title
- Glass-transition behaviour of plasticized starch biopolymer system - A modified Gordon-Taylor approach
- Creator
- Chaudhary, Deeptangshu; Adhikari, Benu; Kasapis, Stefan
- Date
- 2010
- Type
- Text; Journal article
- Identifier
- http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/67125
- Identifier
- vital:3783
- Identifier
-
https://doi.org/10.1016/j.foodhyd.2010.06.002
- Identifier
- ISSN:0268-005X
- Abstract
- Two plasticizers namely, glycerol and xylitol, based on their similar molecular size ( 6.3 Å) but different molecular weights (Glycerol-92; Xylitol-152) were selected for studying the glass-transition behaviour (rubber like behaviour) in multi-plasticized starch biopolymer with about 70% amylopectin structure. In the calorimetry measurements, glass-transition temperatures (onset temperature for bulk viscous flow) of plasticized samples were higher than non-plasticized samples at low water activities, thus showing typical antiplasticization behaviour. However, when plasticizer concentration was increased up to 15% and 20% wt, all plasticized samples showed significant reduction in glass-transition temperature. We used a modified Gordon-Taylor model to understand the competitive plasticization of glycerol and xylitol in presence of water, and suggest that competitive plasticization exists and occurs at a threshold amount of matrix free water content, due to strong three-way interactions: starch-plasticizer, plasticizer-plasticizer/water and starch-water. This competitive interaction is significant in determining the onset temperature for viscous flow behaviour; at higher matrix water content, the Gordon-Taylor constant was relatively unaffected by the plasticizer amount, and water was the dominant plasticizer. A new interaction parameter that separates the starch-plasticizer interaction in a starch-plasticizer-water system is also discussed. © 2010 Elsevier Ltd. All rights reserved.
- Publisher
- Elsevier
- Relation
- Food Hydrocolloids Vol. 25, no. 1 (2010), p. 114-121
- Rights
- Copyright Elsevier
- Rights
- This metadata is freely available under a CCO license
- Subject
- 0908 Food Sciences; Biopolymers; Glass transition; Gordon-Taylor; Structure-property relations
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