physicochemical and emulsifying properties of barijeh (ferula gumosa) gum

ferula gumosa  boiss is one of the natural plants of iran whose exudates (barijeh) can be used in food industry. in the present study the properties of the gum extracted from tubers of ferula gumosa were examined. for this purpose, gum was extracted from crude exudates by alcoholic extraction with 90% (v/v) ethanol. the purity of gum was relatively high, and it was composed mostly of polysaccharide. soybean oil emulsions (10% w/w) were prepared using gum with concentration from 0.2 to 1.0 % (w/w). surface tension, interfacial tension and creaming measurements were performed for all emulsions. particle size measurements, light microscopy observations and rheological studies were performed for 1.0 % gum emulsion. the purified gum was found to reduce surface tension and interfacial tension of emulsions. although particle size distribution measurements showed a slight change in particle size pattern after two month, mean diameter of particles remained constant. the creaming tests confirmed a comparatively good overall stability over a period of two months. the rheological measurements showed the shear thinning nature of emulsions prepared with the barijeh gum. the emulsion stability was attributed to the surface adsorption mechanism.