Dough preparation process is an important stage of bread production which has a significant effect on quality of the end product. Bakery yeast, sourdough and chemical leavening agents are used as leavening agents for the treatment of dough for bread. In this study, bakery yeast, sourdough, sodium bicarbonate and combination of bakery yeast and sodium bicarbonate were used for the production of flat bread (lavash). The firmness of lavash bread texture was analyzed using a texture analyzer device and bread staling at 24, 48 and 72 h after baking was analyzed using DSC device. Also, microstructure of bread was studied by scanning electron microscopy (SEM). The results of DSC showed that bread produced with combination of bakery yeast and sodium bicarbonate, had lower enthalpy (279.84 ± 70.47 J/g) and staling than the other samples. Also, hardness of this sample was low (7.608 ± 0.892 N). The images obtained from SEM showed that diameter of gas bubbles in the bread produced with bakery yeast and combination of bakery yeast and sodium bicarbonate, were higher and their cell walls were thinner.