Fabrication of pH-sensitive gelatin/sodium alginate composite microbeads for potential delivery of resveratrol

Encapsulation technology has become an effective method for improving the utilization of functional ingredients. In this study, a composite network system was constructed using gelatin (GEL) and sodium alginate (SA). Hydrogel beads were prepared through the ionic gelation method and systematically evaluated for their potential use as carriers for resveratrol (RES). The impacts of CaCl 2 concentration(0.05–0.50 mol/L) on several parameters, including mechanical strength, rheological properties, and RES encapsulation efficiency of the hydrogel microbeads, were investigated. The results indicated that the GEL/SA hydrogel microbeads demonstrated optimal overall performance at a CaCl 2 concentration of 0.10 mol/L, with an impressive RES encapsulation rate of 96.6 %. Additionally, the pH sensitivity was remarkable, suppressing the release of RES in the gastric environment. The hydrogel microbeads returned to their initial swelling rate after three cycles of pH reversibility, demonstrating good pH reversibility. Furthermore, in vitro release kinetics studies revealed that the release behavior of RES in simulated intestinal fluid aligned with the Korsmeyer-Peppas model. This study confirmed that GEL/SA composite hydrogel microspheres can achieve efficient encapsulation and controlled release of RES by regulating the Ca 2+ crosslinking density. This approach provides a new strategy and theoretical support for the application of functional ingredients in food delivery systems. • An ionic gelation method was employed to prepare GEL/SA hydrogel beads. • GEL/SA demonstrates effective pH responsiveness and high encapsulation efficiency. • The hydrogel beads in the 0.10 mol/L group demonstrate good pH reversibility. • The hydrogel beads help prevent the premature release of resveratrol in the stomach. • The release of hydrogel beads follows the Korsmeyer-Peppas kinetic model.