Viscoelastic properties of pectin-co-solute mixtures at iso-free-volume states

Stefan Kasapis, Ahmed Al-Alawi, Nejib Guizani, Akhtar J. Khan, John R. Mitchell

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20 Citations (Scopus)

Abstract

Small-deformation oscillatory measurements were performed on pectin-sucrose-glucose syrup systems at a total level of solids of 81%, with the polysaccharide content being fixed at levels of industrial use (1%). The experimental temperature range was between 50 and -50°C. Analysis of the temperature dependence of viscoelastic processes by the equation of Williams, Landel, and Ferry provides values of fractional free volume for the temperatures covering the glass transition region. The shift factors used in the conversion of mechanical spectra into master curves were normalised at suitably different temperatures so that their temperature dependence becomes coincident. The treatment implies an iso-free-volume state and relates to changes in the monomeric friction coefficient with increasing levels of intermolecular interactions in the mixture. A free-volume related glass transition temperature was defined and manipulated markedly by introducing pectin of variable degrees of esterification to the sucrose-glucose syrup system. (C) 2000 Elsevier Science Ltd.

Original languageEnglish
Pages (from-to)399-407
Number of pages9
JournalCarbohydrate Research
Volume329
Issue number2
DOIs
Publication statusPublished - Nov 3 2000

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Keywords

  • High solids
  • Iso-free-volume state
  • Pectin
  • Rheological glass transition temperature

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Organic Chemistry

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