Polysaccharides from sea buckthorn — Ultrasound-assisted enzymatic extraction, purification, structural characterization, and antioxidant activity analysis

This study employed a sophisticated approach consisting of ultrasound-assisted enzyme treatment to extract polysaccharides from sea buckthorn (SBP). The SBP extraction parameters were optimized, the following optimal parameters were identified: solid-liquid ratio of 1:32 g/mL, ultrasound duration of 26 min, ultrasound temperature of 52 °C, and composite enzyme concentration of 6000 U/100 mL, and the maximum extraction yield of SBP was 24.07 ± 0.15 %. The separation and purification of SBP resulted in the isolation of three fractions of polysaccharides (SBPR-1, SBPR-2, SBPR-3). The composition and structural characteristics of the SBPRs were identified. Furthermore, the SBPRs exhibited the characteristic absorption peaks of polysaccharides. Notably, the surface microstructures of the SBPRs showed significant variations. Moreover, all SBPRs demonstrated commendable thermal stability and in vitro antioxidant activity. This study serves as a reference for the development and application of natural antioxidants and provides a theoretical foundation for the environmentally friendly and effective extraction of SBP.