Effect of gum tragacanth on the physicochemical, textural and sensory properties of corn-based gluten-free bread

Celiac Disease (CD) is a common lifelong disorder with small bowel malabsorption and gluten intolerance. The only effective treatment for CD is a strict adherence to a gluten free diet throughout the patient’s lifetime. One of the main challenges in relation to the gluten free bread is to obtain a proper structure and quality. Gluten free breads require polymeric substances that mimic the viscoelastic properties of gluten to provide structure and retain gas. In this research effect of tragacanth in three concentrations (0.5, 1.25 and 2%) and pectin-tragacanth in concentration of 1.5% (1:1) was evaluated on the physicochemical, textural and sensory properties of corn-based gluten-free bread. Specific Volume of the breads was enlarged as the concentration of tragacanth increased compared to the control sample. The lowest weight loss of samples was belonged to the bread containing2% tragacanth that had not significant difference with the sample containing 1.25% tragacanth. With increasing of tragacanth concentrations a significant )P<0.01) increase in moisture content of the sample crumb was observed compared to the control bread. Crumb hardness increased during storage from first to third day and the effect of treatment on crumb hardness was significant )P<0.01). Bread containing 1.25% tragacanth had a softer texture compared with other breads containing hydrocolloids and control bread. However, this difference was not significant (P>0.05). Also the results showed that treatment effect on the sensory properties was not significant (P>0.05), and addition of different concentration of hydrocolloids improved the overall score of sensory evaluation. Generally, according to the results of different tests and statistical analysis which carried out in the present study, it was suggested that the addition of tragacanth in concentration of 1.25% can improve the gluten-free bread quality.