Search

Sugarcane molasses is an agricultural by-product containing sucrose. In this study, the exopolysaccharide (M-EPS) produced by Leuconostoc citreum B-2 in molasses-based medium was characterized, optimized, and its application in set yogurt was investigated. The structure analysis, including gel permeation chromatography, Fourier transform infrared spectroscopy, and nuclear magnetic resonance, revealed that the M-EPS was a linear dextran composed of D-glucose units, which were linked by α-(1→6) glycosidic bonds with 19.3% α-(1→3) branches. The M-EPS showed a lower molecular weight than that produced from sucrose. The M-EPS was added into the set yogurt, and then the water holding capacity, pH, and microstructure of set yogurt were evaluated. Compared with the controls, the addition of M-EPS improved the water holding capacity and reduced the pH of set yogurt. Meanwhile, the structure of the three-dimensional network was also observed in the set yogurt containing M-EPS, indicating that M-EPS had a positive effect on the stability of set yogurt. The results provide a theoretical basis for the cost-effective utilization of sugarcane molasses. [ABSTRACT FROM AUTHOR]

• 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) was produced by Leuconostoc ctireum NM105 from homemade manchurian sauerkraut. After culturing the strain in Man–Rogosa–Sharpe medium containing 5% sucrose at 25 °C for 48 h, the EPS was purified and a yield of 23.5 g/L was achieved. The EPS consisted exclusively of glucose and the weight-average molecular weight was 1.01 × 10 8 Da. The structural characterization of the purified EPS determined by FT-IR, 1 H, 13 C and two-dimensional NMR spectroscopy demonstrated that the glucan contained α-(1 → 6)-linked d -glucopyranose units, 2,6-linked d -glucopyranose units and terminal α- d -glucopyranose units at a ratio of 1:1:1. The microstructure of the dried dextran appeared a sheet-like smooth glittering and highly branched surface. The NM105 dextran showed high water solubility and excellent water retention. All the results suggested that the highly α-(1 → 2) branched dextran might have the potential to serve as valuable polymers applied in foods, cosmetics and other fields. [ABSTRACT FROM AUTHOR]