Evaluating Rheological Behaviour of Tragacanth Gum Blend with QodoumeShirazi, Farsi and Locust Bean Gums

One of the most interesting methods to develop novel rheological and textural properties in food formulation is the application of hydrocolloid blends. In this study, properties of tragacanth gum blends with qodoumeshirazi, farsi and locust bean gums were evaluated. By this purpose initially the rheological behavior of tragacanth, qodoumeshirazi, farsi and locust bean gums were evaluated individually at 0.2% total gum concentration. Further, the rheological behavior of tragacanth gum blend with the mentioned gums in ratios of 20:80, 40:60, 60:40 and 80:20 were investigated between 1.32 and 165 s-1 shear rates. Power law and Herschel-Bulkley models were used to described their rheological behavior.These results showed that all solutions had pseudoplasticbehavior. Among the individual gum solutions,qodoumeshirazi showed by itself yield stress. The consistency coefficient of tragacanth gum was considerably higher than other gums. The apparent viscosities of blend solutions of tragacanth- locust bean gums and tragacanth-farsi gums in the ratio of 20:80 were higher than individual gums, which revealed the existence of synergism between these groups of gums. Since,farsi, qodoumeshirazi and locust bean gums are cheaper than tragacanth gum; it is possible to have cheaper formulation by using them instead oftragacanth gum.