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• PC EPS is a dextran consisting of consecutive α-(1→6)-linked D-glucopyranose units. • The dextran polymer showed an irregular sheet structure and porous surface. • The dextran displayed heat tolerance and high viscosity at low pH properties. • The dextran could coagulate sucrose-supplemented milk. • The dextran has potential applications in food and dairy processing. An exopolysaccharide (EPS)-producing bacterial strain, PC, was isolated from pickled Chinese cabbage and identified as Leuconostoc pseudomesenteroides. EPS yield was up to 30.5 g/L when bacteria were cultivated in Man-Rogosa-Sharpe (MRS) medium containing 5% sucrose at 30°C for 48 h. Further analysis by gas chromatography, high performance size exclusion chromatography, and nuclear magnetic resonance revealed that the EPS consisted of glucose with α-(1→6) linkages and had a molecular weight of 3.13 × 106 Da. Scanning-electron microscopy demonstrated an irregular sheet structure and porous surface, and lumps with an average height of 77.803 nm were observed by atomic force microscopy. Physical-chemical analysis showed that the EPS exhibited excellent thermal stability and possessed high viscosity at high concentration, low temperature and acidic pH, making it promising to be used in thermal processed foods and fermentation of acidic food products. Milk solidification test also suggested the promising potential for application as a dairy and food additive since the EPS could activate the solidification of sucrose-supplemented milk. Taken together, this study provides a commercial guidance for the practical application of PC EPS in food industry and other areas. [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]