Porous Starch-inulin Loaded Quercetin Microcapsules: Characterization, Antioxidant Activity, in-vitro Release, and Storage Stability

Abstract

Quercetin (Q) has many potential health benefits, but its low stability limits its use in functional foods and pharmaceuticals. The low stability of quercetin is a challenge that needs to be addressed to fully realize its therapeutic potential. The purpose of this study was therefore to design a proper carrier based on porous starch (PS) and inulin (IN) in order to improve the stability of Q. The scanning electron microscopy (SEM) images denoted that the Q molecules were adsorbed in the PS pores and partially adhered to the surface of the granules. Both types of the wall material could remarkably enhance the protection of Q against thermal and light degradation. The retention index of Q under different environmental conditions was higher for the PS:IN-Q than PS-Q. The results of Fourier transform infrared spectroscopy (FT-IR) revealed that Q interacted with the wall materials through non-covalent bonds. X-ray diffraction (XRD) also confirmed the encapsulation of Q in the wall materials. The bonding between Q and the hydrogen groups of starch compacted the crystalline regions and increased the relative crystallinity in PS-Q and PS:IN-Q. The DPPH and ABTS scavenging activities of the microcapsules containing the PS and IN were higher than those of free Q. Examination of the in-vitro release profile indicated that the Q release rate was lower from the PS:IN-Q microcapsules (21.6%) than from the PS-Q ones (33.7%). Our findings highlight the significant potential of this novel biopolymer mixture (PS/IN) as a promising wall material for the protection and delivery of bioactive compounds.