Rheological and thermal properties of dough and textural and microstructural characteristics of bread with pulque as leavening agent

This work studied rheological and thermal properties of dough and textural and microstructural features of bread with pulque, a white sap made from the juice of certain species of agave in Mexico, as leavening agent. To this end, a basic dough recipe (wheat flour-33.7%, sugar-2.5%, salt-0.5%, and water-63.3% w/w) was used as control. Dough variations were produced by substituting water (25%, 50%, 75% and 100% v/v) by pulque. The leavening volume of all the dough variations exhibited an increase of about 50% relative to the control dough, where only commercial yeast was used. Increasing pulque concentrations decreased dough apparent viscosity. The addition of pulque also decreased dough crystallinity (approx. 40%), indicating that the fermentation process disrupted the internal organization of starch granules. Furthermore, the incorporation of pulque induced an important decrease (approx. 55%) of the moisture diffusivity in the bread, suggesting that bacteria consortiums in pulque improved water binding by altering the protein structure. In turn, reduced moisture mobility led to reduced weight loss during bread baking. The results showed that pulque is a suitable source of leavening for the fabrication of bread specialties with improved textural and microstructural features.