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 com-pounds, 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)-alpha-D-Manp-(1-* and-* 2)-alpha-D-Manp-(1-* with branches consisting of alpha-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 ox-ygen 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.