Fabrication of Pickering Emulsions Stabilized by Burdock Rhamnogalacturonan Ⅰ (RG-1)-Type Pectin/Zein Composite Particles and Their Utilization for the Delivery of Curcumin

In the present work, Pickering emulsions were fabricated using burdock RG-1-type pectic polysaccharides/zein composite particles as emulsifiers. The effects of polysaccharide concentration, pH, ionic strength, and oil phase volume fraction (φ) on the physicochemical properties of the Pickering emulsions were systematically analyzed. Besides, the efficacy of the emulsions for stabilizing and delivering curcumin were also elucidated. The results showed that the optimal conditions for the formation of Pickering emulsions were pectin concentration 10 mg/mL and pH 3–5. The emulsion was stable under NaCl concentration of 40–200 mmol/L and oil volume fraction of 0.17–0.75. Rheological results showed that low concentration of calcium ion effectively strengthened the interfacial structure of the emulsion containing curcumin, while when the concentration of calcium ion increased to 4 mmol/L, the emulsion gel shrank, reducing its viscoelasticity. The thermal stability and bioavailability of curcumin were significantly improved by high internal phase emulsion encapsulation. The bioavailability of curcumin encapsulated in the cross-linked emulsion with 1 or 2 mmol/L calcium ion was highest, more than 60%. This study is of positive significance to expand the application of RG-1-type pectic polysaccharides/zein composite nanoparticles in food delivery systems.