Core-sheath electrospun nanofibers for encapsulation of Malus baccata polyphenols

Malus baccata polyphenols (MBP) possess considerable bioactivity but suffer from poor physicochemical stability, which limits their practical applications. In this study, coaxial electrospinning was employed to fabricate core-sheath nanofibers (PM-GZ nanofibers) for MBP encapsulation, using PVA/MBP (PM) as the core solution and gelatin/zein (GZ) as the sheath solution. The effects of electrospinning parameters on the morphology and properties of the nanofibers were systematically investigated. Under the optimized conditions (14 wt% PVA, 0.6 wt% MBP, 19 kV voltage, 10 cm receiving distance, 0.1 mL/h core flow rate, 0.5 mL/h sheath flow rate, and 15-19G coaxial needle), the obtained nanofibers exhibited smooth, continuous, and bead-free morphology with distinct core-sheath structures and an average fiber diameter of 120.87 ± 19.29 nm. Furthermore, the nanofibers showed high encapsulation efficiency, favorable thermal stability, enhanced mechanical properties, and improved protection of MBP, attributable to hydrogen bonding and hydrophobic interactions within the fiber matrix. Overall, this study demonstrates that coaxially electrospun core-sheath nanofibers are a promising strategy to significantly enhance the stability and delivery efficiency of natural polyphenols.