Applicability of wheat brewer's spent grain in steamed bread-making based on physicochemical and visual profiles assessment of doughs and breads

Brewer's spent grain (BSG), one of the main byproducts of brewing, has been widely used in the food industry due to its high nutritional components of dietary fiber, proteins, polysaccharides, and polyphenols. This study investigated the influence of wheat brewer's spent grain (WBSG) on the physicochemical properties of dough and steamed bread-making performance. The incorporation of WBSG in wheat flour significantly increased water absorption, development time, and degree of softening while decreasing the stability time of blending dough. Excessive WBSG up to 20% restricted the dough formation. WBSG contributed to the remarkable increase of pasting viscosities, pasting temperature, and immobilized water proportion in doughs. For all doughs, storage moduli (G ') were higher than viscous moduli (G ''). WBSG addition resulted in higher moduli values and the formation of highly networked gluten structure, finally leading to the lower specific volume, spread ratio, and elasticity of bread. Lightness (L*) of bread decreased with increasing WBSG while redness (a*) and total color difference (Delta E) augmented. Low WBSG addition (<= 5%) could endow steamed bread with the appearance of a chocolate-like color and pleasant malt flavor, which is acceptable for most consumers. Nevertheless, the improvement of nutritional and functional characteristics of steamed bread incorporated with WBSG should be more focused in the future.