In vitro release and antioxidant activity of Satsuma mandarin (Citrus reticulata Blanco cv. unshiu) peel flavonoids encapsulated by pectin nanoparticles

Summary The flavonoids of citrus peel extracts ( CPE ) were encapsulated by pectin nanoparticles ( PN s), in an attempt to control the releasing property and improve their antioxidant activity. The physiochemical properties of the obtained PN s were characterised. Flavonoid composition in CPE before and after encapsulation were determined. In vitro release profiles and antioxidant activity of CPE were further evaluated. Results showed the size of spherical PN s obtained was 271.5 ± 5.3 nm. Interestingly, in simulated gastric fluid ( SGF ), 73% flavonoids were released from the naked CPE after 2 h, while only 28.78% from the CPE ‐loaded PN s (E‐ PN s). The releasing rate of flavonoids reached 91.47% from E‐ PN s after 24 h in the simulated intestinal fluid ( SIF ). Moreover, DPPH and ABTS assay revealed that E‐ PN s showed higher antioxidant activity than blank PN s and free CPE . These data showed that the controlled release of CPE might potentially increase its bioaccessibility and there was a synergistic effect between citrus PN s and CPE on the antioxidant activity.