Effect of Sterol Type on Structure of Tubules in Sterol + γ-Oryzanol-Based Organogels

Abstract

The mixture of γ-oryzanol with β-sitosterol forms a network of tubules in edible oil that may serve as an alternative to the network of small crystallites of triglycerides occurring in regular oil structuring. The present experiments demonstrate that the tubules vanish at the melting point of the gel. Moreover, a number of alternative sterols (e.g., ergosterol, stigmasterol, cholesterol, cholestanol) can replace sitosterol in the tubules. The tubule diameter varies between 6.7 and 8.0 nm, the wall thickness between 0.8 and 1.2 nm. The results are consistent with a previously proposed helical ribbon assembly mechanism.

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

“…In this study, homogenous solutions of γ-oryzanol (see Figure 1 for chemical structure; Tsuno Rice Fine Chemicals, Wakayama, Japan) and tall oil sterol (78.5% β-sitosterol, 10.3% β-sitostanol, 8.7% campesterol, and 3.8% of other minor sterols,7,11 Unilever, The Netherlands) mixtures in sunflower oil (Reddy, NV Vandemoortele, Breda, The Netherlands) were prepared by stirring at ∼90 °C using a magnetic stirrer. The minor sterol compounds present in the tall oil sterol have a very similar chemical structure to the β-sitosterol, and it was recently found that the gelling behavior and structural properties of their organogels with γ-oryzanol are similar to β-sitosterol-γ-oryzanol organogels 7,11.…”

“…Furthermore, it was reported that mixtures of γ-oryzanol and β-sitosterol form translucent, firm, and thermo-reversible gels in sunflower oil even when high structurant concentration is used (i.e., >16%, w / w ) 6 , 7. Bot and coworkers found that the firmness and transparency of the gel depend on the oryzanol–sitosterol ratio 6,7,11. The haziness of the gel decreased with increasing γ-oryzanol concentration and the firmest gel was always obtained at the ratio of ∼60–40 w / w oryzanol–sitosterol 6-8.…”

Effect of organogelator and fat source on rheological properties of olive oil-based organogels

“…Different edible gelators were investigated in the literature, such as: triacylglycerols (TAGs), diacylglycerols (DAGs), monoacylglycerols (MAGs) (Calligaris, Da Pieve, Arrighetti, & Barba, 2010;Da Pieve, Calligaris, Co, Nicoli, & Marangoni, 2010;Ojijo, Neeman, Eger, & Shimoni, 2004), fatty acids and fatty alcohols (Schaink, van Malssen, Morgado-Alves, Kalnin, & van der Linden, 2007), sorbitan tri-stearate and/or lecithin (Pernetti, van Malssen, Kalnin, & Flöter, 2007;Shchipunov, 2001), sterol and γ-oryzanol (Bot, den Adel, Roijers, & Regkos, 2009), waxes (Toro-Vazquez, Morales-Rueda, Ajay Mallia, & Weiss, 2010) and others. Among them, monoglycerides are particularly interesting because, in addition to their gelling ability, they are also responsible of positive health effects (Goldstein & Seetharaman, 2011).…”

Towards a multidisciplinary approach to structuring in reduced saturated fat‐based systems – a review

“…Duffy et al. (2009) report systems able to form structure in the aqueous phase, and it has been confirmed (Bot & Agterof, 2006; Bot et al. , 2008; 2009a) that β‐sitosterol–γ‐oryzanol fibril systems are quite unique as they are one of the few combinations capable of forming fibril structures in both aqueous and oil systems.…”