Abstract: To enhance the stability and bioavailability of epigallocatechin gallate (EGCG), this study employed the anti-solvent method to construct pomelo-peel pectin/zein (PP-Zein/EGCG) composite nanoparticles loaded with EGCG. From single factor experiments, the optimum preparation parameters were determined as 2.50 mg/mL, 540 W, 8 mg/mL and 2.0 mg/mL for pomelo peel pectin concentration, ultrasonic power, zein concentration and EGCG concentration, respectively. Fourier transform infrared (FTIR) spectroscopy indicated that nanoparticle formation primarily relied on hydrogen bonds, hydrophobic interactions, and electrostatic interactions. X-ray diffraction (XRD) and microstructural analysis showed that EGCG was fully encapsulated within nanoparticles, forming a stable spherical structure. Stability studies showed that PP-Zein/EGCG nanoparticles maintained high EGCG retention rates under heating (50–100 ℃), a wide pH range (3–11), high ionic strength (30–150 mmol/L NaCl), and high sucrose concentrations (50–250 mg/mL). After storage at 25 ℃ for 42 days, the retention rate of the encapsulated EGCG was 1.46 times higher than that of the free form. In vitro simulated digestion indicated that the nanoparticles effectively prevented the rapid release and degradation of EGCG through their core-shell structure. This study provides a theoretical basis for the stable delivery and bioavailability enhancement of EGCG.

Key words: epigallocatechin gallate, zein, anti-solvent method, nano-encapsulation