The Influence of Concentration and Temperature on the Formation of ¿-Oryzanol + ß-Sitosterol Tubules in Edible Oil Organogels

H.I.M. Sawalha, P. Venema, A. Bot, E. Flöter, E. van der Linden

Research output: Contribution to journalArticleAcademicpeer-review

34 Citations (Scopus)

Abstract

The gelation process of mixtures of ¿-oryzanol and sitosterol structurants in sunflower oil was studied using light scattering, rheology, and micro-scanning calorimetry (Micro-DSC). The relation between temperature and the critical aggregation concentration (CAC) of tubule formation of ¿-oryzanol and sitosterol was determined using these techniques. The temperature dependence of the CAC was used to estimate the binding energy and enthalpic and entropic contribution to the tubular formation process. The binding energy calculated at the corresponding temperatures and CACs were relatively low, in order of 2 RT (4.5 kJ mol-1), which is in accord with the reversibility of the tubular formation process. The formation of the tubules was associated with negative (exothermic) enthalpy change (¿H 0 ) compared with positive entropy term (-T ¿S 0 >0), indicating that the aggregation into tubules is an enthalpy-driven process. The oryzanol–sitosterol ratio affected the aggregation process; solutions with ratio of (60 oryzanol–40 sitosterol) started aggregation at higher temperature compared with other ratios
Original languageEnglish
Pages (from-to)20-25
JournalFood Biophysics
Volume6
Issue number1
DOIs
Publication statusPublished - 2011

Keywords

  • edible oil organogels
  • beta-sitosterol
  • mixtures

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