The study of composition, molecular weight and rheological caracteristics of Zedo gum exudates from Amygdalus scoparia

Gums play roles such as stabilizers, emulsifiers, texture improvement etc in food systems. Physico - chemical properties of gums determine their applications. In this study, some properties of Zedo gum, which exudes from Amygdalus Scoparia, were investigated. We harvested Zedo gums from the trees in Kerman province and separated into white, yellow and red groups. The gums were tested for protein, fat and ash content according to AOAC. Na, Fe, Mg, Ca, K and Zn were determined by ICP and total carbohydrate by phenol sulfuric method. Thermal analysis was done from 30 to 600 °C. Molecular mass was carried out by size exclusion chromatography and rheological behavior was assayed by a Physica MCR 301 rheometer at 25 °C on 2% (w/w/) dispersions. Zedo gums showed significant difference in some compositions and thermal analysis. All samples contained high molecular weight polysaccharides of above 1million Dalton. An increase in strain caused a reduction in storage and loss moduli. No jell-like behavior was observed among the samples and high temperatures had lowering effect on their viscosities. Zedo gums samples with three colors were investigated. It was demonstrated that some phisico-chemical and rheological differences existed among them. The results showed that Zedo gum and gum Arabic were two quite distinct polysaccharides with different properties.