Effect of different microstructural features of soluble and insoluble fibres on gluten-free dough rheology and bread-making

• Soluble fibres decreased dough consistency and insoluble fibres increased it.
• Soluble fibres improved the physicochemical characteristics of gluten-free breads.
• Soluble fibres were found to combine with the hydrocolloid in the aqueous phase.
• Among insoluble fibres, the finer fibres improved bread characteristics.

The aim of this study was to investigate the microstructural features of different fibres and their effect on gluten-free dough rheology and bread-making. Insoluble fibres (oat and bamboo, fine and coarse, potato and pea), and soluble fibres (Nutriose® and polydextrose) were studied. Soluble fibres decreased dough consistency, favoured volume increase during fermentation and produced breads with higher specific volumes, lower hardness, lower luminosity and greater cell density than control breads. The fine insoluble fibres also produced breads with higher specific volumes and lower hardness than controls; however, coarser insoluble fibres gave rise to breads with lower specific volumes and greater hardness than controls. Soluble fibres were found to combine with the hydrocolloid in the aqueous phase, favouring the creation of a film that coated the starch granules and flour particles, giving more stability to the structure, whereas insoluble fibres remained whole, disrupting the structure created.