In this study, the weight average molecular weight (M_w) of three selected biopolymers including guar gum (GG), xanthan gum (XG) and Balangu seed gum (BSG) were determined by light scattering and compared with those obtained by linear rheology. In addition, the number average molecular weight (M_n), z-average molecular weight (M_z), polydispersity index (PDI) and molecular weight distribution (MWD) curves were obtained by frequency sweep data in linear regime. At the end, between a log-normal and a three-parameter log-normal MWD models, the latter better expresses the MWD for all hydrocolloids. These results are important for molecular characterization of biopolymers using a more sensitive and less expensive method of rheology than those previous conventional techniques.

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