Investigating the Impact of Sprouting on Starch Properties of Wheat Flour and Non-Linear Rheological Behavior of Bread Dough

Abstract

This study investigated the physical and technological properties of the sprouted refined (SR), sprouted whole (SW) and unsprouted refined (UR) wheat flours to explore their potential in bread production. The effects of sprouting on the starch properties, including molecular weight, amylase activity, pasting, and crystallinity, were examined. Rheological properties were measured using farinograph, extensograph, and mixograph instruments. Then, a mixture design was used to optimize the flour blends for bread dough formulation. The non-linear rheological properties of the dough samples prepared by these flour blends were analyzed using large amplitude oscillatory shear (LAOS) test. Molecular weight (UR: 669.6 kDa and SR: 390.4 kDa) and the falling number (UR: 485.5 s, SR: 132 s and SW: 62 s) decreased with sprouting. The water absorption of UR and SR were similar (55 and 54 %), but SW had higher water absorption being 61%. The mixograph peak torque (UR: 78.3 %Tq, SR: 63.6 %Tq and SW: 57.4 %Tq) values decreased with sprouting. Comparison of the optimum blends with commercial counterparts in bread dough production was conducted by principal component analysis (PCA) using different rheological properties (GL, eta L,S, and T) at different strain values. The results showed that using a blend of 50.5% UR, 48.5% SR, and 1% SW, as well as 5.1% UR, 51.3% SR, and 43.6% SW, in bread dough formulation resulted in non-rheological properties similar to those of their commercial counterparts: refined bread flour and whole wheat bread flour.