Rheological characterization of the hydrocolloid from Gleditsia amorphoides seeds

Espina Corona Gum (ECG) is extracted from Gleditsia amorphoides seeds and is used as an additive in Argentinean food industry. Its chemical structure corresponds to a galactomannan. ECG was compared with Guar Gum (GG) as regards several properties, among them those related to rheological behavior, the effect of NaCl concentration, temperature and acidity. Experimental results demonstrated that ECG solutions have a shear-thinning behavior, respond to a power-law model, are influenced by temperature, and show a good stability when heated. The presence of NaCl and acidity did not affect ECG solution viscosity. ECG solutions were less viscous and less shear-thinning than GG ones. The viscoelastic behavior shows that, for low frequencies, the viscous modulus is greater than the elastic one up to the crossover point of the frequency, where this behavior is reverted. The apparent viscosity decreased as the frequency of oscillation increased.

► The gum extracted from Gleditsia amorphoides seeds has a pseudo-plastic behavior and fits the power-law model. ► Shear-thinning behavior is influenced by temperature and ECG shows a good stability when heated. ► The presence of NaCl and the presence of GDL do not affect the apparent viscosity of ECG. ► The oscillatory dynamic trials suggest that for low frequencies the viscous modulus is greater than the elastic modulus. ► The apparent viscosity of ECG solutions decreased as the frequency of oscillation increased.