Effect of the refreshment on the liquid sourdough preparation

The aim of this work was to investigate the effect of refreshments on the growth of endogenous microorganisms during liquid sourdough preparation by using an Italian and Mexican wheat flours and its effects on the physicochemical properties (pH, total titratable acidity, water activity, moisture content and reducing sugars). The liquid sourdoughs were prepared (DY 200) and incubated for 6 days at 20 degrees C. The sourdoughs were refreshed every day and compared with the not-refreshed ones. Preliminary results showed that in the early stages of the microbial growth process, their population was greater in the sourdough made from the Mexican wheat flour than that of the Italian one. However, after 6 days, the microbial population was not significantly different in refreshed or not-refreshed samples for both sourdoughs (Italian and Mexican). Similarly, physicochemical properties did not show significant differences.