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The flow behavior of six species of Iranian gum tragacanth dispersions was investigated at different temperatures and ionic strengths, within a concentration range (0.05-1.5% w/w) using a controlled shear rate rheometer. The steady shear measurements showed that all of the gum dispersions had shear-thinning natures. The power law model was used to describe the rheological properties of dispersions and Arrhenius model was used to evaluate the temperature effect. Composition analysis, surface tension measurement, particle size analysis, and color measurement of all the species were also carried out. The results indicated that the six species of gum tragacanth being studied in this paper exhibited significantly different physicochemical properties. Therefore, various species of gum tragacanth can be used instead of different hydrocolloids in a wide range of applications.

Dysphagia is a symptom, commonly found in healthcare residents and the elderly, may lead to undernutrition and negative effects on quality of life. Providing special food products that cannot only be swallowed by patients but also meet nutritional requirements is a challenge for food rheologists and healthcare staff. The purpose of this paper was to review the literature on rheological aspects of dysphagia-oriented products. Also, some suggestions were proposed for better exploitation of rheological data in the field of dysphagia-rheology.