Study on Isolation, Purification, Structure Characterization and Antioxidant Activity of Polysaccharide from Zizyphus jujuba cv. Junzao

The isolation and purification, structure characterization and antioxidant activity of Zizyphus jujuba cv. Junzao polysaccharides were studied. The crude polysaccharide HZPC was extracted from Zizyphus jujuba cv. Junzao by water extraction and ethanol precipitation, and then separated and purified by DEAE-52 anionic chromatography column and Sephadex G-100 dexan gel column. The molecular weight and monosaccharide composition of HZPC-2 were determined by high performance gel chromatography (HPGPC) and ion chromatography (IC), and the structural characteristics of HZPC-2 were studied by ULTRAVIOLET spectrum, infrared spectrum and scanning electron microscope. Finally, the antioxidant activities of HZPC-2 were evaluated. The results showed that HZPC-2 polysaccharide was a neutral polysaccharide with α-glucopyranoside framework (JDP-N), its molecular weight was 3.25×10⁴ Da. It was composed of rhamnose (Rha), arabinose (Ara), galactose (Gal), glucose (Glc), xylose (Xyl), mannose (Man) and galacturonic acid (GalA). The mole ratio was 0.05:0.34:0.29:0.15:0.08:0.02:0.06. Scanning electron microscopy showed that the surface of HZPC-2 was furry-shaped and extended in all directions, and the interior of HZPC-2 was embedded with porous structures. In vitro antioxidant tests showed that HZPC-2 had the strongest scavenging activity against DPPH radical, followed by hydroxyl radical, and the weakest scavenging activity against ABTS radical. It can be used as a potential antioxidant and provide a basis for the development of food with the function of Zizyphus jujuba cv. Junzao polysaccharides.