Effect of different sugars on rheological properties of Balangu seed gum

Hydrocolloids are defined as high weight macromolecules which could dissolve in water and give solutions with highviscosity or gels. In this study, the effect of sucrose, fructose, glucose and lactose at concentrations of 0, 1, 2, 3 and 4% w/w on the rheological properties of Balangu seed gum solution (1%) were investigated. Rheological properties of solutions were measured by a Brookfield rotational viscometer. Results showed that at all solutions, with increasing shear rate, the apparent viscosity decreased, indicating the pseudoplastic behavior of Balangu seed gum. Synergistic interactions between gum and sugars improved the viscosity of solutions and the amount of viscosity change depends on type of sugar. Apparent viscosity clearly increased from 23.1 to 35.1 mPa.s with increasing glucose concentration from 0 to 4 % (shear rate=61.2 s-1). Power law model well described non-Newtonian behavior of Balangu seed gum in the presence of sugars. Fitting with power law model showed that the consistency coefficient (k) and flow behavior index (n) were influenced by the type and sugars content. Addition of sucrose, fructose and lactose led to decreases in flow behavior index and increases in pseudoplastic properties of solutions. Interaction between Balangu seed gum and glucose was maximum and this solution showed the highest apparent viscosity.