Activity of Arabinoxylan Hydrolyzing Enzymes during Mashing with Barley Malt or Barley Malt and Unmalted Wheat

Pilot scale brews were prepared either with 100% barley malt (BM 100 ) or 60% barley malt and 40% unmalted wheat (BM 60 W 40 ). Arabinoxylan and β-glucan hydrolyzing enzyme activities were determined during mashing using two temperature profiles. The measured enzymic activities increased for the BM 100 and BM 60 W 40 mashes in the early stages of mashing. The endoxylanase and α- l -arabinofuranosidase activities remained constant at 50 °C but rapidly decreased above 50 °C. At 72 °C, the endoxylanase and α- l -arabinofuranosidase activities were almost completely lost. The β- d -xylosidase activity only decreased slowly at 63 °C. The β-glucanase activity decreased rapidly at 50 °C and was completely lost after 15 min at 50 °C. From the xylose (Xyl) levels (a measure for arabinoxylan content) in the BM 100 worts (1.28−1.33 g/L), a solubilization of 0.23−0.26% Xyl (% of cereal dry matter) during mashing was calculated. The Xyl levels in the BM 60 W 40 worts (0.92−1.11 g/L) corresponded with a solubilization of 0.12 to 0.15% Xyl during mashing.