The present disclosure relates to methods for improving the nutritional quality of fermentation by-products derived from starch-containing material, wherein the fermentation step is carried out in the presence of a first enzyme composition comprising at least one hemicellulase, and wherein the process comprises further the steps of i) subjecting the fermented mash after the fermentation to a second enzyme composition comprising a beta- 1,3 glucanase and a xylanase, ii) separating the desired fermentation product by distillation.