Effect of Added Brewer's Spent Grain on the Baking Value of Flour and the Quality of Wheat Bread

This study was undertaken to determine the effect of the partial replacement of wheat flour (WF) with barley brewer's spent grain (BBSG) and barley-buckwheat brewer's spent grain (BBSG + B) on dough quality and bread properties, including nutritional value. The contents of brewer's spent grain (BSG) in the blend with wheat flour were 0, 10, and 20%. The quality of the flour blends was assessed with intermediate methods and based on laboratory baking. Analyses were also carried out to determine contents of basic nutrients and energy value. The replacement of part of wheat flour with BBSG and BBSG + B diminished gluten yield and deteriorated its quality (a decreased sedimentation value and stability, and increased dough softening). Changes were also observed in the starch-enzymatic system, resulting in a decreased falling number and maximum paste viscosity. Breads containing both BSG types featured higher yield and lower loaf volume. They had also higher contents of protein, dietary fibre, fat, and ash as well as a lower energy value compared to the wheat bread. Considering the organoleptic traits of breads, the 10% replacement of wheat flour with BSG is recommended in the blend. The BBSG + B was found to elicit more beneficial effects on bread properties than BBSG.