effect of flour extraction rate on flour composition, dough rheological characteristics and quality of flat bread

the effect of flour extraction rate on flour composition, dough rheological characteris-tics and the quality of iranian flat breads (lavash, taftoon and barbari) and their staling rate was investigated. flours with different extraction rates (70, 75, 80, 83, 86, 88, 90 and 93) were subjected to different tests. resultes indicated that, by increasing the extraction rate, the amount of protein, fat, fiber, ash, wet gluten, water absorption and the color of the flours all increased but the moisture content, sedimentation value and falling number decreased. rheological studies of doughs by farinograph showed a reduction in dough stability, whereas the dough mixing tolerance index increased along with the extraction rate. by using an extensigraph it was shown that dough resistance, extensibility and the area under extensigram curves were decreased by increasing the extraction rate. a study of the effects of flours with different extraction rates on bread quality, showed that the overall quality of breads is generally affected by the flour extraction rate. sensory analy-sis of breads in respect to overall quality and staling indicated that the desirable rates of extraction for lavash, taftoon and barbari, breads are 88, 90 and 88 respectively.