ABSTRACT: Nowadays, consumption of whole flours and flours with high extraction rate is recommended, because of their large amount of fiber, vitamins and minerals. Despite nutritional benefits of whole flours, concentration of some undesirable components such as phytic acid is higher than white flour. In this study, the effect of several sourdough lactic acid bacteria on toast bread was investigated. Sourdough was made from lactic acid bacteria (Lb. plantarum, Lb. reuteri) with different dough yields (Dy) and incubated at 30˚C for 20 hours, then added to dough in the ratios of 10, 20 and 30% replacement. Breads supplemented with Lb. plantarum sourdough had lower phytic acid. Higher replacement of sourdough and higher DY caused higher decrease in phytic acid content. Sourdough made from Lb. plantarum, DY = 300 and 30% replacement caused the highest decrease in phytic acid content (49.63 mg/100g). As indicated by the panelists, Lb. reuteri sourdough can present the greatest effect on overall quality score of the breads. DY reduction caused a decrease in bread quality score. Sensory score of toast bread was 81.71 in the samples treated with Lb. reuteri sourdough with DY = 250 and 20% replacement.