Glass transition temperatures and water sorption isotherms of cassava starch

J. Perdomo, A. Cova, A. J. Sandoval, E. Laredo, A. J. Müller, Hilda Lorena García Rodríguez

Research output: Articles / NotesScientific Articlepeer-review

137 Scopus citations

Abstract

The effect of water content on the glass transition temperatures of cassava starch was determined by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA). Samples were transformed to the amorphous state by compression molding at high temperature (as demonstrated by wide angle X-ray diffraction, WAXS), and then the samples were moisture conditioned. Both DSC and DMTA showed that water anti-plasticized cassava starch at lower moisture contents, and plasticized it at higher water contents. Samples with higher moisture contents stored at room temperature, 45 °C and 80 °C underwent retrogradation as indicated by WAXS. Sorption isotherms of cassava starch showed that for aw values lower than around 0.85, the sorption capacity decreased with increasing temperature; while the opposite behavior was observed at aw > 0.85. This inversion point (aw = 0.85) was attributed to the fact that more active sites were exposed to the adsorption processes, due to the enhanced molecular mobility promoted in the amorphous regions by starch crystallization.

Original languageEnglish
Pages (from-to)305-313
Number of pages9
JournalCarbohydrate Polymers
Volume76
Issue number2
DOIs
StatePublished - 17 Mar 2009

Keywords

  • Cassava starch
  • DSC and DMTA
  • Glass transition
  • Plasticizing and anti-plasticizing effects
  • Retrogradation
  • Sorption isotherm
  • WAXS

Fingerprint

Dive into the research topics of 'Glass transition temperatures and water sorption isotherms of cassava starch'. Together they form a unique fingerprint.

Cite this