Fermentation affects the composition and foaming properties of the aqueous phase of dough from soft wheat flour

• Fermentation increases amylase inhibitor and puroindoline extractability in dough liquor.
• Dough liquor from (defatted) fermented dough produces much and very stable foam.
• Crumb of bread supplemented with dough liquor from fermented dough has very fine cells.
• The low pH of the latter dough liquor increases surface activity of puroindolines.

A quality characteristic of bread is that it has a homogeneous and fine crumb structure. The latter depends on the number and size of gas cells present in dough as well as their stabilization during fermentation and baking. Discontinuities in the gluten–starch matrix result in liquid films formed from the dough aqueous phase taking over gas cell stabilization. This is especially important in late fermentation. How fermentation affects (the composition and properties of) the dough aqueous phase is unclear. In the present study, the dough's aqueous phase was isolated as dough liquor (DL) from unfermented and fermented dough made from flour and water (with or without added sugar and salt). Fermentation increased DL yield and changed its composition. With regards to surface active proteins, especially the extractability of α-amylase/trypsin inhibitors and puroindolines (PINs) in DL increased. More foam of higher stability was formed from DL from (defatted) fermented dough than from that from (defatted) flour-water dough. PINs were specifically enriched in foam from DL from fermented dough. Finally, supplementation of dough with the latter DL sample yielded bread with finer gas cells than those of control bread. Thus, fermentation enhances the foaming properties of DL, which is also translated in improved bread quality.

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