The modulation of buckwheat flour techno-functional properties by ultrasound treatment

The buckwheat is a naturally gluten-free pseudocereal, rich in phytochemicals, phenols and functional proteins, however, the functional characteristics of its flour in baking process are not as performing as those of wheat flour. The aim of this thesis was to analyse how the functional, viscosimetric and antioxidant properties of two variety of buckwheat (Polish and Italian) flours change in response to an ultrasound (US) pre-treatment carried out on different solid:liquid ratio. For this, in the differently treated Polish buckwheat samples some functional properties (water absorption index, water solubility index, swelling power, water holding capacity, water absorption capacity, foaming capacity and stability, emulsifying activity and emulsion stability) were analysed. Moreover, the thermoviscous test, antioxidant capacity and polyphenol content were quantified. Finally, bread samples, obtained with treated and untreated Polish buckwheat flour were analysed for baking loss, specific volume, colour analysis of crust, porosity and hardness. The obtained results showed that the US pre-treatment increased the water holding capacity, improved the foam stability, but decreased the ability to form foams and emulsions as well as the viscosity of the treated flour samples. The breads formulated with US treated flours had a more uniform pore distribution in the crumb and were softer than the breads formulated with untreated flour. Moreover, US pre-treatment had no effects on surface colour and phenolic content of obtained bread. In conclusion, the application of US on buckwheat flour can be a good alternative to the use of additives in formulation in order to obtain gluten-free and nutritionally rich final products.