Potential of barley straw pretreated with a lignin inhibitor as an adjunct during beer production

Abstract

SummaryBarley straw is an agricultural residue of low added value used for alcohol production through chemical pretreatments. However, chemical pretreatments are expensive and generate residues, preventing the possible application of this product in the food. This study aims to use piperonylic acid as a lignin inhibitor applied in a barley field to obtain a pretreated straw more accessible to structural carbohydrates, releasing fermentable sugars and partially replacing malt in beer. Straws showed structural and chemical changes with SEM, FTIR and compositional analysis. These changes enabled the fermentable sugars release when inserted in wort with 2.5% of barley straw, using cellulase isolated or a xylanase and cellulase mixture in 1:2 proportion, maintaining a final enzyme concentration of 16 U mL−1. Barley straw pretreated with lignin inhibitor can be used as a brewing adjunct, increasing the release of fermentable sugars and bioactive compounds.