Preparation of highly stable oleogel-based nanoemulsions for encapsulation and controlled release of curcumin

Oleogels have been proposed as suitable systems for the encapsulation and delivery of lipophilic bioactive compounds. This work aimed to produce stable nanoemulsions of gelled-oil particles using monoglyceride (MG) oleogels loaded with curcumin. High-speed homogenization followed by ultrasonication was used for obtaining colloidal dispersions. The effects of ultrasonication processing parameters and formulation were evaluated to optimize particle size, polydispersity index (PDI), and stability during storage. All sonication parameters had a significant effect on particle size and PDI. A Pluronic F-68 + Tween 80 surfactant mixture with the lowest oleogel/aqueous phase ratio (5/95) produced nanoemulsions which were at least 10-month stable. The nanoemulsions showed a higher encapsulation efficiency than the sample without the gelator (73.85-91.05% vs. 56.99%). Furthermore, it was corroborated that structuring oil particles with MG crystals produces a matrix that entraps curcumin molecules and slows down their release. These findings provide useful information for the development of new nutraceutical products.