Structural analysis and properties of dextran produced by Weissella confusa and the effect of different cereals on its rheological characteristics

• Published in: International journal of biological macromolecules 2020-01, Vol.143, p.305-313
• Main Authors: Heperkan, Z. Dilek, Bolluk, Meltem, Bülbül, Sedef
• Format: Article
• Language: English
• Subjects: Boza; Dextran; Exopolysaccharide; FTIR; Weissella confusa
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2019.12.036

Weissella confusa is a commonly found species in boza, a highly viscous beverage obtained from fermented cereals. Exopolysaccharide (EPS) produced by Weissella confusa C19 was characterized and the role of different cereals on its rheological characteristics were studied. Thus, the effect of the type of cereals on textural characteristics of boza for standard boza production and the fate of W. confusa during fermentation were assessed. W. confusa C19 EPS consisted of glucose, sucrose and 1.7 mg/kg protein. Structural characterization of water-soluble dextran was determined by 1H NMR, functional groups were identified by Fourier transform infrared spectroscopy (FT-IR) and the crystal structure was determined by X-ray diffraction (XRD). After EPS characterization, different cereal-based media including maize, oat, rice and wheat were used for the growth and EPS production of the bacterium. The rheologial properties of EPS obtained from different cereal-based media showed that the steady shear behavior of EPS was pseudoplastic. W. confusa C19 is a unique strain that can adapt to the environment containing high sugar to produce high amounts of polysaccharides. Besides new information on EPS from W. confusa origin, this study showed that the amount of dextran increased using solid media fortified with different cereals. •W. confusa C19 is a unique strain that are able to produce high amount of EPS•Solid media allow observation and collection of EPS more easily•W. confusa C19 EPS was consisted of glucose, sucrose and 1.7 mg/kg protein•The highest amount of dextran was obtained from rice medium•The dried dextran was transparent like glass and very hard like stone•The number of colonies decreased gradually day by day in mMRS agar•The cells were bursted due to high sugar concentration in cereal-based media