Rheological and microstructural evolution of the most common gluten-free flours and starches during bread fermentation and baking

Mechanistic relations between the evolution of the starch/flour structure, dough rheology and bread quality were investigated using the most common flours and starches in gluten-free bread-making. Micrographs showed that the small wheat starch granules filled the spaces of the big granules, forming a uniform starch-hydrocolloid matrix. This granular advantage decreased the consistency and increased the uniformity of wheat-starch based doughs throughout fermentation, as shown by micrographs and the higher critical strain. The viscoelastic properties of the different doughs strongly influenced the bread volume and the crumb texture. Thus, starch-based breads showed higher specific volume and lower hardness, especially those made with wheat starch, whose lower pasting temperature also reinforced the continuous phase of the crumb. On the other hand, the large potato starch granules did not form a continuous starch-hydrocolloid matrix, resulting in breads with the lowest specific volume, elasticity, cohesiveness and resilience, and the highest hardness.