Rice bran wax structured oleogels and in vitro bioaccessibility of curcumin

Abstract

Curcumin, the bioactive compound found in turmeric, exhibits a wide range of health-promoting properties. However, its application in food formulations and as nutritional supplements is limited by its poor bioaccessibility. This study investigates the effects of curcumin on the structure formation and physical properties of oleogels made with three different concentrations of rice bran wax (RBW) (2%, 6%, and 10% w/w) compared to an ungelled control oil and examines the bioaccessibility of curcumin contained in those lipid systems. The physical and structural properties were characterized using a penetration test, solid fat content, polarized light microscopy, differential scanning calorimetry, and X-ray diffraction (XRD). Data analysis revealed no significant differences in polymorphic or thermal properties between oleogels with and without curcumin; however, differences in microstructural properties were documented for oleogels with curcumin. Moreover, the percent of lipid crystallinity in 6% and 10% RBW oleogel increased in samples containing curcumin. An in vitro simulated digestion study showed that curcumin bioaccessibility significantly increased with increasing RBW content relative to the ungelled control. Results from this study provide insight into the potential utilization of RBW oleogels for delivering curcumin and other poorly water-soluble compounds in food, dietary supplement, pharmaceutical, and cosmetic products.

Healthier Oils: A New Scope in the Development of Functional Meat and Dairy Products: A Review

“…Additionally, the strategies attempt to mimic the appearance, plasticity, and rheological properties of animal fat in addition to improving nutritional quality and the lipid profile [13,78]. In this regard, as shown in Figure 2, pre-emulsification, oil encapsulation, oleogels, and gelled emulsions are several varieties of solid oil structured systems that offer promising results as fat substitutes in the development of healthier foods [79][80][81][82][83][84]. Table 2 presents several studies where vegetable and marine oils were structured using different strategies to be applied in foods.…”

“…Oleogel formation allows a high concentration of liquid oil (>90%) to be structured into a "gel-like" system [119]. These new oil structures can be obtained directly by adding the oleogelator to the oil to be structured or indirectly by developing an emulsion beforehand and then dehydrating this structure to form the oleogel [83,120]. Several compounds can be used for oleogelators; the most widely utilized in food products include lipid-based gelators (bee wax, rice bran wax, candelilla wax, fatty alcohols, etc.)…”

“…As regards direct gelation methods, the lipid-based gelators are widely used to elaborate the oleogels [83,120,124,125]. Therefore, in a study carried out by Malvano et al [120] to replace the butter in the preparation of sponge cake, an oleogel was made by dissolving beeswax at 3 g/100 g in olive oil (97 g/100 g) at 85 • C and continuously agitating it in a vortex at 100 rpm.…”

“…Similarly, Zbikowska et al [125] made oleogels by dissolving different concentrations of beeswax (2, 4, 6 and 8 g/100 g) in peanut oil at 80 • C. This mixture was then cooled until the oleogel was obtained. In the study conducted by Dent et al [83], rice bran wax was added as an oleogelator in different proportions (2, 6, and 10 g/100 g w/w) to corn oil at 90 • C with or without added curcumin. Then, after complete dissolution, the mixture was cooled to obtain the oleogel.…”

Stabilization of Rice Bran: A Review

“…RB also has great potential in applications as an ingredient in infant formulas and gluten-free products due to it being highly soluble, hypoallergenic, and gluten-free [26,27]. In addition to direct utilization, RB is also used as a source of RB protein concentrate [26][27][28][29][30][31], RB oil [32,33], RB fiber [34][35][36], RB wax [37,38], γ-oryzanol [39], and a phytochemical-rich ingredient [40]. Furthermore, RB is not only used for culinary purposes but also in the pharmaceutical and cosmetic industries.…”