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An exopolysaccharide (EPS) was produced by Leuconostoc pseudomesenteroides DRP-5 isolated from homemade wine. The EPS was obtained with ethanol extraction, which was further purified by chromatography of Sephadex G-100 to get a purified fraction. The monosaccharide composition of the EPS was glucose, and its molecular weight (Mw) was 6.23 × 10 6 Da, as determined by gas chromatography (GC) and high-performance size-exclusion chromatography (HPSEC). Fourier transform infrared spectra (FT-IR) and nuclear magnetic resonance spectra (NMR) showed that the EPS was a linear glucan with α-(1→6)-linked glucosidic bonds. The water holding capacity (WHC), water solubility index (WSI) and emulsifying activity (EA) of DRP-5 EPS were 296.76 ± 18.93%, 98.62 ± 3.57% and 87.22 ± 2.18%, respectively. DRP-5 EPS have a higher degradation temperature of 278.36 °C, suggesting high thermal stability of the EPS. Also, DRP-5 EPS was found to have moderate 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, hydroxyl radical, superoxide anion radical, 2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) radical, Fe 2+ scavenging activities and reducing power. All these characteristics suggest that DRP-5 EPS might have potential applications in the pharmaceutical, cosmetic and food industries. [ABSTRACT FROM AUTHOR]

A water-soluble exopolysaccharide (EPS)-producing strain YF32 was isolated from soybean paste, which was then identified as Leuconostoc pseudomesenteroides . After culturing the strain in Man-Rogosa-Sharpe (MRS) medium containing 5% sucrose at 30 °C for 48 h, the EPS was purified, and a yield of 12.5 g/L was achieved. The weight-average molecular weight (Mw) was 5.54 × 10 6 Da by high-performance size-exclusion chromatography (HPSEC). The structural characterization of the purified EPS was determined by gas chromatography (GC), Fourier transform infrared (FT-IR), 1 H, 13 C nuclear magnetic resonance (NMR) spectroscopy. The results demonstrated that the exopolysaccharide was glucan with a peak, a linear backbone composed of consecutive α-(1 → 6)-linked d -glucopyranose units. No branching was observed in the dextran structure. The degradation temperature (Td) of EPS was 307.62 °C, which suggested that dextran exhibited high thermal stability. YF32 dextran also showed high water solubility and emulsibility. All results suggested that dextran has the potential to be applied in food fields as a food additive. [ABSTRACT FROM AUTHOR]