The effect of p H , salts and sugars on the rheological properties of cress seed ( L epidium sativum ) gum

Summary Effect of shear rate (15–600 s −1 ), gum concentration (1–2%), pH (3–9), sucrose (10–40%), lactose (5–15%), NaCl (100–300 m m ) and CaCl 2 (5–50 m m ) was evaluated on apparent viscosity ( η a ), flow behaviour index ( n ), consistency coefficient ( K ) and yield stress ( τ 0 ) indices of cress seed gum ( CSG ) solutions. Different rheological models were used to fit the experimental data, although the H erschel– B ulkley model was found the best model. An increase in gum concentration led to an increase in τ 0 , η a , and k and a decrease in n values. The addition of salts lowered the k value; however, the n value showed slight significant change. The presence of sugar resulted in the enhancement of n , k , τ 0 and η ap values. The existence of yield stress and pseudoplastic behaviour of CSG , its stability against salts, wide range of p H and synergic effect of sugar make it a good thickener and stabiliser in food formulations.