PHYSICOCHEMICAL, RHEOLOGICAL AND STRUCTURAL CHARACTERISTICS OF ALCOHOL PRECIPITATED FRACTION OF GUM TRAGACANTH

Obtaining specific polysaccharide of gum by separating other parts appears to be an approach to get a hydrocolloid with a higher quality and new functional properties. Therefore, gum tragacanth (GT) was used for these aims. The characterization of alcohol precipitated part of GT were performed in terms of physico-chemical compositions (moisture, ash, protein, color and transparency); rheological behaviors aqueous solutions at different concentration, temperature, pH, presence of salt and sucrose; and structural characterization (FTIR, XRD, DSC and SEM). Applied process has no effect on sucrose its chemical compositions which is important for preserving of progressing application. Clearer solution was obtained for purified sample which was important for sensorial properties of end-product. Rheological experiments indicated that separation insoluble part (bassorin) from GT increased viscosity and improved the stability to the different environmental conditions. FTIR experiment results confirmed that tragacanthin and bassorin is physically mixture not chemically bonded. The improvement of thermal stability of GT was also observed by DSC as a result of bassorin separation. The results suggest that extraction soluble part of GT resulted in higher rheological and structural characteristics which may help to widen its application.