Processing & rheological properties of wheat flour dough and bread containing high levels of soluble dietary fibres blends

- Breads containing up to 23% soluble fibres blend with density < 0.25 g·cm− 3.
- DF addition increased the extensional viscosity of dough.
- For DF ≤ 23%, little changes of bread crumb cellular structure were observed.
- Inulin addition led to dough and bread properties different from DF blend.

Wheat flour doughs were processed with soluble dietary fibres (DF) added up to 40% (w/w flour). DF were made of a ternary mixture of maltodextrins (MT, 3/5), pectins (PE, 1/5) and inulin (IN, 1/5). The addition of DF decreased the specific mechanical energy developed by the mixer, mainly because of water addition. It increased the ratio of storage moduli and the elongational viscosity of the dough, but decreased the strain hardening index. Energy input and rheological changes at mixing largely explained the decreases of porosity characteristic time and stability time during fermentation. It was possible to add up to 30% DF with a moderate increase of bread density, and 20%, with little change of crumb cellular structure. Hence, the changes of bread crumb texture were not mainly due to bread density, but rather likely to the changes of properties of the intrinsic material. Results obtained by addition of single fibre source, especially inulin, deviated from the main trends observed for texture and rheological properties. These results provide a good basis to design breads with increased dietary fibre content.

Variations of characteristic time of fermentation of bread doughs enriched with ternary blends of soluble fibres (from △, control, to ▲, 29% SF on flour sub.) with their elongational viscosity (at strain rate = 1 s− 1) and related impact on crumb grain and density.148