Effect of gamma irradiation on structural properties and rheological behavior of binary biopolymer blend: A case study on guar gum-sage seed gum blends

Abstract

In this study, different gum powders (guar gum (GG), sage seed gum (SSG) and guar-sage seed gums (GG-SSG) were irradiated at 0, 5, and 10 kGy. FTIR analysis revealed some small changes in transmittance of gum samples with gamma irradiation. Flow behavior of the gum solutions (1% w/w) revealed shear thinning behavior with a n value lower than 1. The viscosity of gum solutions (1% w/w) decreased significantly with increase of irradiation dose from 0 to 10 kGy which was in consistent with the effect of irradiation dose on the consistency index (k). Herschel–Bulkley and Sisko models with higher values of determination coefficient (R2) were found to be the best models to explain the steady shear properties of non-irradiated and irradiated gum solutions. Irradiation doses (5 and 10 kGy) changed the flow behavior of guar gum solution (1%) from non-Newtonian shear-thinning to Newtonian behavior. G’ and G’’ in GG, SSG, and GG-SSG were observed to decrease in strain sweep test as the irradiation dose was increased from 0 to 10 kGy. In SSG and GG-SSG, G’ was greater than G’’ with no cross over in all the applied frequency range, while guar gum exhibited a solid-like behavior after cross over point. Frequency sweep rheological parameters of gum solutions (1%) including G’, G’’, and (η*) also affected by gamma irradiation and decreased significantly with increasing irradiation dose from 0 to 10 kGy (p<0.05).