Dilute solution properties of Balangu (Lallemantia royleana) seed gum: effect of temperature, salt, and sugar

Abstract

The interaction between hydrocolloids and solvent/cosolutes are the predominant factors determining their functional properties in food systems. In this research, the influence of different temperatures, salts and sugars were investigated on some molecular parameters of Balangu seed gum (BSG) as a new potential source of hydrocolloid. The results revealed that BSG has a high molecular weight (3.65 × 10(6)g/mole) and intrinsic viscosity (7236.18 ml/g), rather flexible chain with a chain flexibility parameter of 1156.53, low stiffness parameter (0.346 for Na(+) and 0.507 for Ca(2+)) and hydrogel content (46%). It was observed that except for water, the solutions of different salts (NaCl and CaCl(2)) and sugars (sucrose and lactose) are poor solvents for BSG as indicated by a monotonous decrease in intrinsic viscosity, swollen specific volume, shape function, hydration parameter, and coil dimensions. The parameters representing the interactions of BSG molecules with different cosolutes, i.e. hydrogel content and Huggins constant, were observed to increase significantly as the ionic strength and sugar concentrations increased from 0.005 to 0.05 M and 2.5 to 40% w/v, respectively. In addition, the elevated temperatures (20-50 °C) induced a clear contraction in BSG dimensional and shape parameters along with a decrease in solvent quality and the extent of associated water molecules through hydrogen bonds and/or physical entrainment. These results may be of high significance when considering the influence of major additives generally used in food products, such as various salts and sugars, and/or frequent processing parameters like temperature on rheological and functional points of view.