Potato fibre preparation (PFP), as the by-product of industrial potato starch isolation, can be a potential functional additive in the food technology due to its sorption properties. The objective was to study industrial potato fibre preparation used as a supplement of wheat flour (15 g per 1 kg of wheat flour) to obtain the following thermally-stabilised complex: wheat starch–water–gluten proteins–mineral components. While determining the affinity of fibre to water, for the wheat flour or potato fibre preparation, the predominant amount of the insoluble fraction (IDF) of dietary fibre over the soluble fraction (SDF) was observed. Due to PFP sorption properties, the supplementation of wheat flour with this preparation enhanced the swelling capacity of starch granules in the dough and favoured gelling as well as mechanical and molecular behaviour of water in the bread structure. The microstructure proofs of bread crumbs indicated an indirect participation of potato fibre components in fibrous construction of gluten network formation. The complementation of soluble and insoluble fibre fractions and some elements, especially potassium, phosphorus, calcium, magnesium or microelements iron, zinc, copper, could be provided in baking products. The results indicate that this potato fibre preparation could be applied as dietary component in nutritional prophylaxis in everyday diet of adults and young people as well.