Encapsulation and release profiles of caffeine from microparticles

The purpose of this study was to encapsulate caffeine in alginate-chitosan cross-linked microparticles enriched with ascorbic acid by applying electrostatic extrusion technique. Three different forms of caffeine were encapsulated: liquid extract of caffeine from the plant guarana (Paullinia cupana), food-grade solid caffeine and analytical-grade caffeine. High performance liquid chromatography (HPLC-PDA) was used to evaluate the release kinetics of caffeine from microbeads in water, while the corresponding antioxidant capacity was evaluated by applying the ABTS radical scavenging assay. Scanning electron microscopy and laser diffraction particle size determination were used to provide information about the physical properties of microparticles. The microbeads encapsulating caffeine were uniformly sized spheres of about 600-800 μm. The encapsulation efficiency of all microparticles ranged between 70-80%. Caffeine was mainly released within 10-15 min, depending on the used caffeine form, while the ascorbic acid was relatively rapidly released from microbeads according to antioxidant capacity exhibited in water. The obtained results suggest that electrostatic extrusion can be applied for the entrapment of caffeine in alginate-chitosan microbeads, while the addition of ascorbic acid further enhances the antioxidant activity of such obtained microcapsules