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

Technical competence for testing environmental quality elements: Accreditation of the Serbian environmental protection agency

This paper describes the implementation of the SRPS ISO/IEC 17025:2006 standard in the Environmental Protection Agency, a state authority that performs the work of testing the quality of surface and ground water, sediment and air, according to the criteria of the Accreditation Body of Serbia (ATS). The success of maintenance of the acreditation system is presented by the new approach, by showing compliance indicator of the Accredation Body of Serbia as an objective indicator of competence for doing the given jobs. The paper contributes to the understanding of the importance of accreditation of jobs within the state administration, the body that examines the elements of the environment, which confirms its technical competence