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 (BM100) or 60% barley malt and 40% unmalted wheat (BM60W40). Arabinoxylan and beta-glucan hydrolyzing enzyme activities were determined during mashing using two temperature profiles. The measured enzymic activities increased for the BM100 and BM60W40 mashes in the early stages of mashing. The endoxylanase and alpha-L-arabinofuranosidase activities remained constant at 50 degrees C but rapidly decreased above 50 degrees C. At 72 degrees C, the endoxylanase and alpha-L-arabinofuranosidase activities were almost completely lost. The beta-D-xylosidase activity only decreased slowly at 63 degrees C. The beta-glucanase activity decreased rapidly at 50 degrees C and was completely lost after 15 min at 50 degrees C. From the xylose (Xyl) levels (a measure for arabinoxylan content) in the BM100 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 BM60W40 worts (0.92-1.11 g/L) corresponded with a solubilization of 0.12 to 0.15% Xyl during mashing.