Physicochemical and Functional Properties of Polyphenolic Core Gel Microcapsules from Rose Petals (Rose L.): A Comparative Study

The aim of this study was to evaluate the effect of matrix type and dose of polyphenolic core from rose petals on the physicochemical and functional properties of microcapsules. Microcapsules were obtained by ionotropic gelation using four carrier systems: sodium alginate (SA), sodium alginate with added starch (SA + S), protein isolate (SA + P), and vegetable gum (SA + G). Polyphenolic compounds isolated from rose petals (E) were used as the core at six concentrations (0.25, 0.5, 1.0, 1.5, 2.0, and 2.5%). Differences between microcapsules were assessed based on physicochemical properties, polyphenol and anthocyanin content, antioxidant activity, swelling index, and biocompatibility. The results showed that both the extract dose and the matrix system significantly affected the analyzed parameters. The highest encapsulation efficiency was demonstrated for the lowest dose (0.25%), regardless of the matrix used. Total polyphenol and anthocyanin content significantly increased for all microcapsule versions with increasing extract dose, with the highest concentrations obtained for the SA + G system. These results strongly correlated with antioxidant activity and biocompatibility with human colonocyte membranes. In turn, the swelling index decreased with extract dose, showing the highest values in small intestinal fluid and the lowest in gastric fluid. These findings may have significant implications for the design of functional carriers for use in food and dietary supplement production.