Quercetin Loaded Nanostructured Lipid Carrier for Food Fortification: Preparation, Characterization and <i>in vitro</i> Study

Abstract Nanostructured lipid carriers ( NLC ) have been developed for encapsulation of bioactive flavonoids such as quercetin ( QT ). In this study, QT‐NLC was prepared by high‐pressure homogenization method. For the optimized QT‐NLC , the average particle size, the zeta potential and the average entrapment efficiency were 129 ± 12.13 nm, −26 ± 4 m V and 93.50 ± 0.35%, respectively. The developed QT‐NLC had good physical stability at ambient temperature condition. I n vitro antioxidant activities assays showed comparable antioxidant activity of QT‐NLC to free QT . Fourier transform‐infrared spectroscopy analysis of QT‐NLC confirmed encapsulation of QT in NLC and no chemical interaction between QT and lipid matrix. Lyophilization was proved feasible for the storage of QT‐NLC dispersion. The in vitro release study in simulated gastrointestinal fluids showed a sustained release profile of QT‐NLC . The release of the QT‐NLC in simulated gastric fluids and simulated intestinal fluids was best fitted to H iguchi and R igter‐ P eppas model, respectively. The gastrointestinal tract model indicated that the bioaccessibility of QT within simulated small intestinal conditions was improved by encapsulation. The QT‐NLC also showed potential application in soft beverage. Particle size remained relatively steady in simulated beverage solutions for 2 months. It demonstrated that nanostructure lipid carriers could be designed as delivery system for encapsulation of bioactive compounds and applied in functional food industries. Practical Applications Quercetin ( QT ) is one of the most common dietary polyphenols widely found in the plant kingdom, which has numerous benefits to human body. But due to its low solubility and unstability when exposed to alkaline media, photo and warm temperature, its application in the food industry is limited. This research aims at incorporating QT into nanostructure lipid carriers manufactured by high‐pressure homogenization method for improved bioaccessibility and achieving its application in food such as soft beverage.