extraction and physicochemical properties of barijeh (ferula galbaniflua) gum

ferula galbaniflua boiss is one of the natural plants of iran that its exudates, barijeh gum, can be used in food industry. the present study explored the properties of a new gum extracted from tubers of ferula galbaniflua. for this purpose, barijeh gum was extracted from crude exudates by alcoholic extraction with 90% ethanol. the purity of gum was relatively high, and it composed mostly of saccharides. the composition of gum was analyzed using hplc, and by comparing sample with standards, the constitution of sugars and uronic acids in extracted sample were determinated. in this research the effect of temperature (50, 70, 90 °c) and ph (4, 7, 10) on the extraction yield, viscosity and on the purity of extracted gum investigated. it was found that, extraction yield in acidic ph was highest and rising temperature lead to more yield. by the other way, increasing temperature and reducing ph reduced protein content in extracted gum. increasing temperature of extraction medium decreased viscosity of gum suspension. also, alkaline extraction yield less viscosity of gum suspension. our analysis indicated presence of galactose and arabinose that galactose:arabinose ratio was 6:1. soybean oil emulsions (10% w/w) were prepared using different concentrations of barijeh gum. the purified barijeh gum was found to reduce surface tension and interfacial tensions of emulsions. although particle size distribution measurements showed a slight change in particle size pattern after two months but mean diameter of particles was constant. the creaming tests confirmed a comparatively good overall stability over a period of two months.