Formulation, characterization and in vitro digestion of polysaccharide reinforced Ca-alginate microbeads encapsulating Citrus medica L. phenolics

Abstract

Using ionotropic gelation technique, Citrus medica L. phenolics was encapsulated in Ca-alginate microbeads to deliver associated health benefits. Microbeads were strengthened by polysaccharide fillers (starch, carrageenan, and pectin) at different concentrations (0.5–4 g/100 mL) for an effective phenolic encapsulation, controlled release, and swelling. All blended solutions were subjected to a similar set of instrumental conditions for controlled extrusion. Whereas, three polymeric combinations (ASE, ACE, and APE) with higher encapsulation efficiencies (EE%) were selected. Furthermore, the impact of polysaccharide fillers on physical properties of Ca-alginate microbeads, such as size, sphericity factor, viscosity, and water activity, was investigated. In contrast to AE, ASE, and ACE microbeads, APE (pectin; 2 g/100 mL) showed highest EE% (90.18) and antioxidant activity with a half maximal effective concentration (EC50) of 108.97 μg/mL. Under in vitro gastrointestinal conditions, APE outperformed in terms of controlled release and swelling. While, UHPLC-DAD-QTOF-IMS also showed the higher amount of hesperidin (264.11 mg/100 g) and polymethoxy-flavones (PMFs) encapsulated in APE microbeads. The chemical interaction was confirmed by FTIR, which showed similar C–H stretching of aromatic components in APE and CMEE. Overall, the study revealed that Ca-alginate microbeads with polysaccharide fillers improved entrapment and controlled delivery of citrus phenolics for therapeutic uses.