RHEOLOGICAL CHANGES IN WHEAT SOURDOUGH DURING CONTROLLED AND SPONTANEOUS FERMENTATION

The changing rheological characteristics of wheat doughs during fermen tation at 30 degrees C for 72 hr were measured using a controlled stre ss rheometer. Dynamic oscillation tests were performed at frequencies ranging from 0.01 to 10 Hz. Wheat sourdoughs (dough yield 200) were pr epared with a mixed starter culture containing typical hetero- and hom ofermentation process were compared to results from spontaneous fermen tation. Maximum phase angle values, especially at low frequencies, wer e closely related to total gas production in the doughs. Complex visco sity decreased during fermentation and reached lower final values for doughs without starter culture. Heating characteristics of doughs afte r various fermentation times were measure at temperatures ranging from 30 to 80 degrees C. The highest values for complex viscosity were fou nd at approximate to 65 degrees C. When heated, fermented doughs produ ced weaker gels than fresh doughs. The temperatures at which these max ima occurred increased significantly with fermentation time for sponta neously fermented dough.