الفهرس 
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Abstract
The aim of this thesis was undertaken to investigate the effect of replacement of wheat flour (82%, 72% extraction rate) with different percentages of blends of sweet potato flour in balady bread and pan bread making. Sweet potato flours have lipids, crude fiber and ash contents higher than wheat flour. While moisture and crude protein content of sweet potato flours were lower than wheat flours. And sweet potato flours have mineral (Fe,K,Ca,Mg) contents higher than wheat flour. And it’s a high content in Beta-carotene. Rheological properties of dough were affected by the percentage of replacement of wheat flour (82%, 72% extraction rate) with blends of sweet potato flour by replacement 10%, 20%and 30%. Dough stability in most cases decreased with an increase in wheat flour dilution, indicating an overall weakening of the dough. The resistance to extension (B.U), extensibility (E) , proportional number (R/E) and the area under the curve (energy) were decreased as the ratio of sweet potato flour increased comparison with control, in wheat flour(82% extraction rate). But in wheat flour (72% extraction rate), The resistance to extension (B.U), proportional number (R/E) and the area under the curve (energy) were decreased with an increase sweet potato flours. At the same time the extensibility (E) was increased as the ratio of sweet potato flour increased comparison with control. Bread made from wheat flour substituted with blends of sweet potato flours at levels10%, 20% and 30%. In general, all bread with flour replacement were significantly different than control sample for all sensory properties at high substitution levels which caused a significant deterioration in flat bread properties. Flat bread can be produced with good acceptability by using 10% wheat flour substitution with blend of sweet potato flours. The data revealed that a decrease in the alkaline water retention capacity (AWRC) took place with increasing the storage period of bread and the level of blends added to the flour, compared with control value. Results revealed that the bread produced from sweet potato flour was greatly decreased in their moisture, protein, and total carbohydrate content than control samples. Moreover, the percent of change was increased in crude fiber, ash fat and mineral contents than control bread samples. The results explained the effects of sweet potato flour as antifungal and increased the preservation period of balady bread and pan bread compared with control.