Rheological and thermal properties of dough and textural and microstructural features of bread obtained from nixtamalized corn/wheat flour blends

Abstract

Bread made with corn flour has a rich tradition in several countries. On the other hand, nixtamalization is a process conferring malleability and functionality to corn flour via calcium incorporation. The aim of this work was to study the rheological and thermal properties of dough, and the textural and microstructural features of bread obtained from nixtamalized corn (NCF)/wheat flour (WF) blends. Thermal analysis indicated that NCF promoted the interaction between starch molecules and lipids. The incorporation of NCF improved the viscoelasticity of dough, indicative that the participation of lower amounts of gluten (protein) due to WF substitution by NCF might be compensated by the cross-linking capacity of calcium ions. Morphological analysis via SEM showed that as NCF was incorporated, a more compact and porous microstructure arose that caused breads to exhibit increasing hardness, but a decrease in the rest of the textural characteristics. Increasing amounts of NCF led to more homogeneous bread crust color, characterized by a more subdued lightness and yellow hue. Overall, NCF offers a mean to improve dough viscoelasticity and granular microstructure of wheat-based bread.