An acidic polysaccharide from Ziziphus Jujuba cv. Muzao: Purification and structural characterization

•An acidic polysaccharide (PZMP2-2) was isolated and purified from Z. Jujuba cv. Muzao.•Structural characteristics of PZMP2-2 was analyzed by HPGPC, UV, FT-IR, GC–MS, NMR.•Structural features of PZMP2-2 was characterized by SEM, XRD, AFM. A novel acidic polysaccharide fraction (PZMP2-2) was isolated from Ziziphus Jujuba cv. Muzao fruit via hot water extraction and purified by DEAE-Sepharose FF and Sephacryl S-300 column chromatography. PZMP2-2 consisted of rhamnose, arabinose, xylose, galactose, and galacturonic acid in a ratio of 1.18: 5.23: 0.22: 2.68: 2.20, with a molecular weight of 62.73 kDa. Structural features of PZMP2-2 were investigated using FT-IR, SEM, AFM, GC–MS analysis and NMR spectroscopy. Methylation and GC–MS analysis revealed that the main glycosidic bonds in PZMP2-2 comprised 1-linked Galp, 1,3-linked Araf, 1,2,4-linked Rhap, 1,3-linked Galp, 1,4-linked GalpA and 1,3,5-linked Araf. NMR analysis indicate that PZMP 2–2 has a linear backbone of (1 → 4)-linked GlcpA and (1 → 2,4)-linked Rhap residues, with branches at the O-4 position, consisting of Araf and Galp residues.