The Effect of Extruded Sorghum Flour and Hydrocolloids on the Physical and Chemical Properties of Gluten-free Cookie

Celiac disease is a digestive autoimmune disorder caused by the digestion of gluten. As of current, the only known treatment for this disease is to get a gluten-free diet. In this study, sorghum flour (extruded and non-extruded), xanthan and Lepidium perfoliatum seed gum were applied at three concentrations, namely 0, 0.3, 0.6 and 1.0%, to improve physical and chemical characteristics of gluten-free cookies. The cookies were subjected to physical and chemical characterization (spread factor, textural properties, gelatinization temperature, enthalpy, color, percent porosity, and crust thickness) and sensory evaluations. The results showed that, the cookies made from extruded sorghum flour (100%) containing Lepidium perfoliatum seed gum at 0.3% had the lowest L* and the highest a* and b* contents. Moreover, the samples composed of non-extruded sorghum flour had the highest adhesiveness and stiffness, while post-baking stiffness of the cookies composed of extruded sorghum flour was lower than those of other cookies; i.e. the cookies made from extruded sorghum flour were of softer texture. These cookies had also the highest spread factor, percent porosity, and crust thickness, and these properties were observed to increase with increasing the gum concentration. Overall acceptability of the cookies made from extruded sorghum flour was significantly higher than those composed of non-extruded sorghum flour, indicating extruded sorghum flour as an appropriate ingredient for producing gluten-free cookies.