Modification of inulin for improved encapsulation efficiency and controlled release of quercetin

Quercetin (Q) was encapsulated with inulin (In) and acetylated inulin (AcIn) through a freeze-drying process to increase its stability and bioavailability. Hence, the difference in structure, encapsulation, and morphology properties, as well as release study between encapsulated quercetin with inulin (In-Q) and acetylated inulin (AcIn-Q) were investigated. The successful modification of inulin into acetylated inulin and the encapsulation of quercetin within the In and AcIn matrixes were confirmed by the Fourier Transform Infrared (FT-IR) analysis. In terms of encapsulation efficiency and loading capacity, AcIn-Q showed higher (82.74% and 32.85%) than In-Q (80.69% and 22.22%), respectively (p<0.05). In addition, scanning electron microscopy (SEM) analysis showed that the AcIn-Q encapsulated showed more uniform, spherical particles with smoother surfaces than In-Q. Moreover, AcIn-Q exhibited a more significant stable quercetin release pattern than the In-Q in vitro test. From the release kinetic assay, the release profile of AcIn-Q and In-Q were fitted to the Korsmeyer-Peppas model based on the correlation coefficient (R²>0.95). Additionally, AcIn-Q was controlled by a non-Fickian diffusion mechanism, while In-Q was regulated by Fickian diffusion. In summary, our study proposes the encapsulation of quercetin with acetylated inulin as an encapsulation agent through freeze-drying to improve release kinetics and the potential application for therapeutic efficacy.