Structural characterization of exopolysaccharides from Weissella cibaria NC516.11 in distiller grains and its improvement in gluten-free dough

In this study, an exopolysaccharide (EPS) was produced by Weissella cibaria NC516.11 isolated from distiller grains of Chinese Baijiu. The structural characterization of EPS determined using fourier transform infrared spectra and nuclear magnetic resonance spectra demonstrated that W. cibaria NC516.11 had α-(1 → 6) (93.46%) d-glucose linkages with a few α-(1 → 3) (6.54%) d-glucose linked branches. The monosaccharide composition of the EPS was glucose, and its molecular weight was 2.82 × 106 Da. Scanning electron microscopy showed that the microstructure of EPS had a three-dimensional structure at low magnification and a particle structure that protruded from the surface at high magnification. The addition of EPS into dough can promote the cross-linking of starch molecules and increase the water-holding capacity. Dynamic rheology indicated that the aqueous solution of EPS is a pseudoplastic fluid, and the higher the concentration of EPS, the greater the viscosity. The addition of EPS to the gluten-free dough showed G' > G″, which could increase the viscoelastic properties of the dough and enhance the gluten network.