Effects of flour mean particle size, size distribution and water content on rheological properties of wheat flour doughs

Abstract

This investigation is focused on the granulometric and rheological analysis of two kinds of wheat flour, i.e. type 0 and type 00. The granulometric analysis was carried out using a laser diffraction particle size analyzer. The particle size distribution of the type 0 and 00 flours, expressed as the mass median diameter (D(v,0.5)), was 80.922 µm and 71.686 µm, respectively. The rheological characterization of physical mixtures of wheat flour and water was carried out by means of small deformation dynamic oscillatory measurements. The rheological measurements evidenced a different behavior of the two samples of flour when they were mixed with water. Namely, the progressive addition of water to the type 0 wheat flour favored a decrease of G′ and G″ values, emphasizing that the dough becomes less full-bodied, while its structure remains unmodified; in fact, the phase-angle was not influenced by the water content. On the contrary, the type 00 wheat flour mixed with increased water content provided a dough characterized by lower elastic and viscous moduli, even though the behavior of the phase angle progressively varied. The different results may be due to the different particle size distribution of the flour and the different percentage of gluten present in each. Thanks to this parallel study of the particle size distribution of flours and the rheological behavior of the derived doughs, new food preparation procedures and new research on adulteration in the bread production can be designed.