Structural characterization and antioxidant properties of a novel polysaccharide isolated from Jiuzao in vitro and in vivo

Recovery of valuable compounds from Baijiu by-products is one of the important challenges currently faced by the brewing industry. In recent years, the research on Baijiu has shifted from Baijiu flavour to functional compounds, especially the extraction and activity of Jiuzao polysaccharides. The polysaccharide from Laowuzeng Jiuzao (LWZ-P’) was extracted by water extraction and alcohol precipitation, and then purified by column chromatography to obtain pure polysaccharide. The physical and chemical properties of LWZ-P’ were analyzed by UV, FT-IR, GPC, NMR, and HPAEC. As a result, LWZ-P’ was mainly composed of mannose (37.26 %), with a relative molecular weight of 32 402 g/mol, possessing the primary backbone of → 3)-α-d-Manp-(1 → and → 2)-α-d-Manp-(1 → with branches consisting of α-d-Manp-(1 → residue. In addition, LWZ-P’ had significant activities of DPPH radical, ABTS free radical, superoxide anion free radical and hydroxyl free radical in a dose-dependent manner. Meanwhile, LWZ-P’ presented a protective effect against the generation of H2O2-induced reactive oxygen species, effectively inhibiting cell death in zebrafish. The current study aims to recover polysaccharides from brewed products, better understand the functional value of Jiuzao, and lay a theoretical foundation for the development of Jiuzao polysaccharide-related foods.