Dielectric barrier discharge plasma-assisted extraction of Rhamnogalacturonan-I pectin from pomelo peel: Structural characterization and application in an emulsion gel delivery system

Pomelo peel, a major byproduct of pomelo processing, was utilized to isolate rhamnogalacturonan-I (RG-I) pectin via a novel approach combining low-concentration alkaline extraction with dielectric barrier discharge (DBD) plasma treatment, followed by characterization. The extracted pectin (DAP) was characterized by its esterification degree, monosaccharide composition, molecular weight, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), triple-helix structure, and scanning electron microscopy (SEM). Results revealed that DBD increased its RG-I content while preserving its overall structure. Additionally, the effects of DAP, oil phase, CaCO₃ concentration, and glucono-δ-lactone (GDL) concentration on the properties of the resulting emulsion gel were investigated. In vitro release studies indicated that the emulsion gel followed the Korsmeyer-Peppas model, demonstrating controlled-release behavior. After simulated in vitro digestion, 70% of the encapsulated naringenin available for release in intestine. This study provides a theoretical foundation for the green extraction of RG-I pectin from pomelo peel and application in delivery systems.