Structural and Rheological Properties of Succinoglycan Biogums Made from Low-Quality Date Syrup or Sucrose Using Agrobacterium radiobacter Inoculation

This study examines and compares the structural and rheological properties of succinoglycan exopolysaccharide made by fermentation of sucrose or date syrup at identical temperature, pH, and total soluble solid. Using thin-layer chromatography (TLC), Fourier transform infrared (FTIR) spectroscopy, and rotational viscometery structural and rheological properties of prepared exopolysaccharides were assessed. The variables under studies were biogum concentrations (0.5%, 1.0%, 1.5%, and 2.0% w/w), temperature (5, 25 and 40°C), and pH (2.5, 4.0, 7.0, and 10.0). Results revealed that the quantity of exopolysaccharide produced in the date syrup (DSE) medium was three to five times greater than that of sucrose (SE) medium. The biogums exhibited non-Newtonian, shear-thinning behavior, and the viscosity of DSE was higher than SE at all tested concentrations. The TLC and FTIR spectroscopy assessments designated that the biogum is composed of glucose and galactose units, carrying a carboxylic group and indicated the presence of succinoglycan. The outcomes of this study could be useful to food industries seeking low cost biogum.