Gelation behavior and the stability of multicomponent sterol-based oleogels

Novel fat mimetic materials, such as oleogels, are advancing the personalization of healthier food products and can be developed from low molecular weight compounds such as γ oryzanol and β-sitosterol. Following molecular assembly, the formation of a tubular system ensues, which seems to be influenced by elements such as the oleogelators’ concentration and ratio, cooling rates, and storage periods. Sterol-based oleogels were formulated under distinct environmental conditions, and a comprehensive study aimed to assess the effects of the mentioned factors on oleogel formation and stability, through visual observation and by using techniques such as small-angle X-ray scattering, X-ray diffraction, confocal Raman spectroscopy, rheology, and polarized microscopy. The long, rod-like conformations, identified by small-angle X-ray scattering, showed that different cooling rates influence oleogels’ texture. Raman spectra showed that the stabilization time is associated with the interfibrillar aggregation, which occurred differently for 8 and 10 wt%, with a proven relationship between ferulic acid and the tubular formation. This report gives fundamental insight into the critical point of gelation, referring to the time scale of the molecular stabilization. Our results verify that understanding the structuring mechanisms of oleogelation is decisive for the processing and manufacturing of novel foods which integrate oleogels in their structure.This work was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of the UID/BIO/04469/2019 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004 funded by the European Regional Development Fund under the scope of Norte2020—Programa Operacional Regional do Norte. We also acknowledge the fellowship of Artur Martins, supported by the doctoral advanced training call NORTE-69-2015-15, funded by the European Social Fund under the scope of Norte2020—Programa Operacional Regional do Norte.