Rheological Characteristics of Composite Flour with Linseed Fibre – Relationship to Bread Quality

Hrušková M., Švec I. (2017): Rheological characteristics of composite flour with linseed fibre – relation to bread quality. Czech J. Food Sci., 35: 424–431. Linseed fibre represents a rich natural source of dietary fibre. Here, we report that the addition of linseed fibre at levels of 2.5 and 5.0% changes the viscosity of wheat flour as well as the rheological properties of non-fermented and fermented dough. The differences recorded between fibre from golden and brown flax seeds (GF and BF, respectively) were not significant; BF caused a stronger increase in non-fermented dough elasticity. The addition of both variants reduced fermentation times and partially decreased dough volumes during the three phases of the fermentation process. The results of the baking test corresponded with the altered rheological parameters of dough. Based on principal component and cluster analyses, representative features for each rheological test were identified: amylograph maximum (amylograph test), the pasting temperature (RVA test), dough softening degree (farinograph test), extensigraph ratio (extensigraph test) were selected as the representative features. For the evaluation of fermented dough behaviour, wheat flour-linseed fibre composites could be differentiated according to fermentation time (fermentograph test) and dough volume (OTG test). Statistics also confirmed the appropriateness of the crumb firmness parameter for a detailed specification of bread quality.