Effect of gamma irradiation on the physicochemical properties of gum tragacanth (Astragalus campatus)

Gum tragacanth (GT) is an Iranian native gum used in various industries. This study was carried out to evaluate the effect of different doses of gamma irradiation (0, 4, 8, 16, and 30 kGy) on some physicochemical (color, solubility, pH, WAC), structural (FTIR), rheological (viscosity, consistency and flow behaviour) and stabilizing capability of GT. Based on our findings, at higher doses of gamma irradiation the solubility and b* value improved while the WAC and pH decreased. Moreover, the FTIR results showed that the functional groups of GT were not significantly affected by gamma irradiation. On the other hand, the apparent viscosity of gum dispersion decreased with increasing in total absorbed dose likely due to reduce of side branches and radiolysis of the glycosidic bonds. Furthermore, irradiation had inverse effect on the stabilizing capability of tragacanth because of losing side branches and steric repulsion or steric stabilization. The flow behaviour of gum dispersions shifted from non-Newtonian to Newtonian one

Keywords:

Gum tragacanth , Gamma irradiation , Physicochemical , Rheology