Thermal relaxation of gelatin and date flesh measured by isothermal condition in Differential Scanning Calorimetry (DSC) and its relation to the structural and mechanical glass transition

Mohammad Shafiur Rahman, Ghalib Said Al-Saidi

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9 Citations (Scopus)


A new innovative method was developed to measure the thermal-relaxation by maintaining isothermal condition in a Differential Scanning Calorimetry (DSC). The DSC thermal-relaxation characteristics of gelatin and date flesh were found to be related with the structural- and mechanical-glass transition measured by conventional DSC linear-heating and thermal-mechanical analysis (i.e, Differential Thermal Mechanical Analysis, DMTA). Initial slope of the thermal relaxation curve (i.e., heat flow versus relaxation time) was determined and it was plotted as a function of relaxation temperature (i.e., isothermal condition). The initial slope-temperature graph showed three thermal relaxation characteristics: limited mobile, freely mobile and restricted mobile regions. The region 1 showed limited molecular mobility with increasing temperature, while region 2 showed free mobility with increasing temperature sensitivity. The intersection of the regions 1 and 2 was related to the structural-glass transition measured by conventional linear-heating in a DSC. The region 3 showed restricted mobility due to enhanced interactions of the phases at higher temperature. This region 3 was related to the entangled flow region measured by thermal-mechanical analysis in a DMTA.

Original languageEnglish
Pages (from-to)931-944
Number of pages14
JournalInternational Journal of Food Properties
Issue number4
Publication statusPublished - Jul 2010



  • Glass transition
  • Mechanical characteristics
  • Molecular mobility
  • Structure
  • Thermal relaxation

ASJC Scopus subject areas

  • Food Science

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