Crystallization, Polymorphism and Stability of Nanostructured Lipid Carriers Developed with Soybean Oil, Fully Hydrogenated Soybean Oil and Free Phytosterols for Food Applications

Abstract

The aim of this work was the development of nanostructured lipid carriers (NLC) using conventional fats and oils (soybean oil, SO and fully hydrogenated soybean oil, FHSO) for incorporation of free phytosterols (FP). FP are lipophilic bioactive compounds which can reduce blood cholesterol levels, through a competitive mechanism of absorption, aiding in the prevention of cardiovascular diseases. However, FP presents difficulties related to technological applications in foods due to the high melting point. In this way, NLC can be a means of making feasible incorporation of FP in foods. NLC were obtained in aqueous dispersion through the emulsification process, followed by high-pressure homogenization (HPH) using 3 and 5 cycles at 800 bar, with subsequent crystallization and stabilization of the lipid matrices (LM). The emulsifiers used were soybean lecithin (SL), ethoxylated sorbitan monooleate (T80) and sorbitan monostearate (S60). The thermal and crystalline behavior of the LM, FP and NLC were evaluated. NLCs were characterized by size and polydispersity. FP presented high crystallization (126°C) and melting (137°C) temperatures, but this did not avoid its incorporation into NLC. The NLC presented size between 154 to 534 nm and polydispersity ranging from 0.1 to 0.5, the lower limits being obtained with the T80. NLC were found to require lower temperatures to crystallize and polymorphic transitions were accelerated. This study indicated that the conventional raw materials were compatible with the development of NLC with FP.