Mechanisms Behind Distiller’s Grains Impact on Wheat Dough and Bread Quality

Distiller’s grains, by-product from ethanol production, can be a new source for nutritionally enriched bakery products, particularly because of its high amount of dietary fibre and protein. Ingredients rich in fibre provoke challenges to the dough and bread system; therefore, mechanisms behind dried distiller’s grains (DDGs) impact on wheat bread must be evaluated. So, dough and bread characteristics were analysed in bread containing 0–20 % DDG, and effects of pH, particle size and furfural as DDG metabolite were studied. As a result, wheat bread incorporating DDG provides smaller volume from 20 to 45 %, firmer crumb up to a factor of 6 and reduced springiness up to 10 %. However, pH adjustment balanced the negative influence, and the low pH of DDG was revealed as the most influential parameter. The variation of particle sizes could not influence dough or bread characteristics significantly. While the low pH of DDG and the high amount of dietary fibre do not completely explain the negative impacts, inhibiting effects on the activity of Saccharomyces cerevisiae were evaluated. DDGs contain 2.7 ppm furfural as a consequence of the drying process, so its role as inhibiting compound was investigated in a model suspension and dough. It was confirmed that furfural is contributing to structure weakening effects in dough.