Gelation Behavior and Stability of Multicomponent Sterol-Based Oleogels

Abstract

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.

Food-Grade Oleogels: Trends in Analysis, Characterization, and Applicability

“…The formed gels are clear and slightly cloudy [105]. The literature on the conditions of formation and stability of this type of oleogels is rich [21,59,105,115,116].…”

Role of Stearic Acid as the Crystal Habit Modifier in Candelilla Wax-Groundnut Oil Oleogels

“…It may also signify the -CH 2 vibrational bending of methylene groups due to the presence of candelilla wax. Additionally, two peaks at 1309 and 1269 cm −1 corresponded to the -CH 3 /=CH-H group, and a peak at 1156 cm −1 corresponded to the -C=O group (ester) [67]. A peak at 1082 cm −1 represented the -C-O ester structure, while the peak at 861 cm −1 represented =CH 2 wagging.…”

Atomic Force Microscopy of Phytosterol Based Edible Oleogels

“…AFM is a powerful tool for providing insight into the gel network structure, but, in common with other imaging techniques, it does not provide information about the molecular interactions that underpin the formation of these structures. It is, therefore, useful to combine AFM with spectroscopic techniques such as UV–Vis absorption, circular-dichroism (CD), Raman, or FTIR [ 9 , 38 , 39 ]. For absorbance techniques, due to the high concentration of the gelator in typical oleogels (e.g., >5% for phytosterol gels), thin films are necessary to avoid saturation of the absorption peaks probed by these techniques.…”