Microstructure of β-Sitosterol:γ-Oryzanol Edible Organogels

Andrew B. Matheson, Vasileios Koutsos, Georgios Dalkas, Stephen Robert Euston, Paul Clegg

Research output: Contribution to journalArticlepeer-review

58 Citations (Scopus)
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Rheology and atomic force microscopy (AFM) were employed to examine the microstructure of β-sitosterol:γ-oryzanol organogels in sunflower oil. Using time-resolved rheology, we followed gel formation, paying specific attention to the fibril aggregation process, which had not been studied in detail previously for this system. Using AFM, we observed gel structures directly and obtained detailed information on the gel structure, far exceeding previous studies. Our analysis suggests that though gels are formed by the self-assembly and aggregation of one-dimensional fibrils, the manner in which these fibrils aggregate into ribbons results in complex structures of higher dimensionality. We emphasize that it is a surprise to find ribbons and not twisted strands. Comparing AFM images of 10% w/w and 20% w/w gelator systems, we observed differences in the degree of branching which are consistent with the rheology. We also observed the individual self-assembled fibrils which make up these gels with much greater clarity than in previous microscopy studies, and the fibril diameters of ∼9.8 nm we measured agree excellently with those obtained from existing small-angle neutron scattering data. These results provide new insight into the structure and formation kinetics of this important organogel system.
Original languageEnglish
Pages (from-to)4537-4542
Number of pages6
Issue number18
Early online date21 Apr 2017
Publication statusPublished - 9 May 2017


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