Encapsulation of resveratrol in alginate microcapsules using internal gelation technique: Fabrication, characterization and release kinetics

Abstract

Resveratrol (RES) is a proven anticancer, antioxidant, anti-inflammatory, and cardioprotective compound. However, low bioavailability, poor water solubility, and sensitivity to UV light and heat limit RES's use in food applications. In this study, we aim to protect RES by encapsulating it in sodium alginate (NaAlg) matrix using internal gelation, followed by drying the moist microencapsulates using spray and freeze-drying techniques. The spray-dried microencapsulates exhibited a smaller mean diameter (5.57 ± 2.40 μm), higher encapsulation efficiency (91.32 ± 1.98%), and higher ζ-potential (−61.9 ± 2.33 mV) compared to freeze-dried microencapsulates. SEM images revealed the smooth and spherical surface of the spray-dried microencapsulates, while the freeze-dried samples exhibited irregular shapes and porous textures. FTIR results showed polyelectrolyte interactions between NaAlg, RES, and CaCO3. XRD and DSC results confirmed the incorporation of RES in the NaAlg matrix. Spray-dried microencapsulates demonstrate the highest RES retention of 80.89 ± 0.70% and 78.59 ± 0.27% after 4 h of UV light and thermal treatments, respectively. In vitro release studies showed that spray-dried microencapsulates demonstrate a delayed gastric release compared to freeze-dried microencapsulates. The release mechanism of RES from the microencapsulates was effectively described by the Shalin-Peppas model.