Sourdough was prepared with cellular suspension containing 10(9) cfu of each strain mL(-1) and incubated at 28 degrees C for 24 h and at 37 degrees C for 4 h. Two different sourdough levels (20 and 40%) were used in bread dough preparation. The bread doughs were proofed at 30 degrees C and 85% relative humidity for 60/120/180 min. When glutenin changes that occurred in samples 17, 18, 19, and 20 (40% SD 28) are compared with those that appeared in controls, it is obvious that, the relative intensities of some of the protein bands slightly decreased and a few fainter protein bands appeared (which did not exist in controls). A few fainter protein bands corresponding to the MM approximate to 25 kDa (high-mobility region) and the MM approximate to 66 kDa (low-mobility region) were appeared in the same samples. In the samples prepared with 20% sourdoughs incubated at 28 or 37 degrees C, the bands were still evident after 180 min of proof. This can be explained that glutenin fractions were not hydrolysed in these applications due to the delay in pH drop. The use of 40% sourdough incubated at 28 degrees C for 24 h resulted in sticky doughs and breads with lower volume, harder texture, unsatisfactory crumb grain and unpleasant flavour than the rest of the samples. The use of sourdoughs incubated at 37 degrees C for 4 h caused positive effect on loaf volumes, specific loaf volumes and crumb structure.