Dairy ingredients such as nonfat dry milk (NFDM), ultra filtered cheese whey, and whey protein concentrate are widely used in the preparation of bakery products. The nutritional, organoleptic and some functional properties of bread enriched by dairy products are improved. Increased water absorption, reduced staling rate, and increased crust color are some of the advantages of dairy ingredients in bread baking. On the other hand, dough slackening and volume-depressing effects with no heated dairy fractions have been reported frequently. The performance of dairy ingredients in baking has been the subject of many publications, and almost every milk fraction has been described as loaf volume-depressing. In order to eliminate defects caused by the addition of dairy ingredients in the formulation and further increasing of bread shelf life several modifying method developed that in this study, the method of heat modifying was used. This method is based on the thought that believes with the thermal improving the disturbance effect of thiol bonds in proteins of dairy compounds in gluten network is resolved and whey proteins besides being denatured form polymers and may even gel, and also increases their water holding capacity. Dairy ingredients used in this project were none fat dry milk (34% protein), ultra filtered cheese whey powder (9.5% protein) and whey concentrate powder (81.17% protein) and their effects in modified and unmodified states (in level of 5% based on flour dry weight and in two states of modifying acidic (3.35) and slightly alkaline (7.5) pH) on reducing the rate of staling in Iranian flat bread (Taftoon), its flavor and color and also dough rheological properties were compared. Obtained results showed that treatments containing modified dairy ingredients could delay the staling of bread better than unmodified types and also improve dough farinograph and extensograph properties. The results were evaluated in a completely randomized design and Duncan's multiple range tests was used for comparison of means in statistical level of 5%. Differences between mean of modified treatments and their self unmodified types were quite significant. The remarkable point was that treatment containing ultra filtered cheese whey modified in slightly alkaline pH, despite the low amount of protein, contrary to previous thought could delay staling of bread much better than the others. It can be said increase in lactose amount of dairy ingredients beside pH can be more effective than dairy ingredients proteins.