Encapsulation of Resveratrol using internal gelation: Fabrication and characterization of microspheres

Abstract

Bioactive compounds including Resveratrol (RES) have been proven to have anticancer, antioxidant, anti-inflammatory, and cardio protective effects. However, the low bioavailability, poor water solubility, and sensitivity to UV light and heat render RES unsuitable for use in food applications. These problems can be alleviated by encapsulating RES. Internal gelation is a promising encapsulation technique that has the potential to protect RES from adverse environmental conditions. The aim of the current study was to protect RES using internal gelation of sodium alginate (NaAlg) with calcium carbonate (CaCO3), followed by spray and freeze-drying techniques. The results showed that spray-dried powder had a smaller median diameter (≈ 0.460 μm), higher encapsulation efficiency (85.46 ±1.62%), higher zeta potential (-61.9 ± 2.33 mV), and better poly dispersibility index (0.047). SEM images revealed that spray-dried samples have a spherical shape and smooth surface; whereas freeze-dried particles are irregular in shape and porous in texture. FTIR results showed polyelectrolyte interaction between alginate, resveratrol, and CaCO3. XRD and DSC results confirmed changes in the physical state of resveratrol from crystalline to amorphous and the formation of RES-loaded NaAlg microspheres. Fluorescence results confirmed that the interaction between RES and NaAlg was primarily driven by electrostatic interaction and hydrogen bonding. The UV light stability (365 nm, 4 h) and thermal stability (90 °C, 4 h) of both spray and freeze-dried samples were significantly higher than for the free RES. Spray-dried microspheres showed the highest RES retention of 80.89 ± 0.701% and 78.59 ± 0.265% after 4 h of UV light and thermal treatments respectively. These findings demonstrate that microencapsulation using internal gelation followed by drying is a promising strategy for improving the stability of resveratrol and making it more suitable for use in food and pharmaceutical applications.