Purification and characterization of exopolysaccharide produced by Weissella cibaria YB-1 from pickle Chinese cabbage

Abstract

An exopolysaccharide (EPS) was produced by Weissella cibaria YB-1 isolated from pickle Chinese cabbage. The EPS was purified and characterized. The monosaccharide composition of the EPS was glucose, and its molecular mass was 3.89 × 106 Da, as determined by gas chromatography (GC) and high performance liquid chromatography (HPLC). The structural characterization of purified EPS determined by Fourier transform infrared (FT-IR) spectra and nuclear magnetic resonance (NMR) spectra demonstrated that W. cibaria YB-1 synthesized a linear dextran that predominately had α-(1 → 6) glycosidic linkages with only a few α-(1 → 3) (4.3%) linked branches. The water solubility index (WSI), water holding capacity (WHC) and emulsifying activity (EA) of YB-1 dextran were 95.23 ± 4.45, 287.84 ± 16.23 and 84.43 ± 3.65%, respectively. The in-vitro antioxidant activities of the dextran showed good scavenging effects on superoxide anion radical and hydroxyl radical.