ARABINOXYLAN AND ARABINOXYLAN HYDROLYZING ACTIVITIES IN BARLEY MALTS AND WORTS DERIVED FROM THEM

The water-extractable and total arabinoxylan contents of su: bar ley m alts varied between 0.49-0.69% (all analytical data expressed as a pro portion of dry malt) and 6.40-6.93% respectively. Centrifuged wort ara binoxylan (0.62-0.93%) represented 10 to 14% of the total barley malt arabinoxylan. During brewing some monomeric arabinose (ara) (0.02-0.03 %) and xylose (xyl) (0.03-0.06%) were released. There was a linear rel ationship (R-2 = 0.65; n = 6) between the centrifuged wort arabinoxyla n contents and endoxylanase activities in the malts as well as between the levels of arabinoxylan solubilised during brewing and the endoxyl anase activities of malts (R-2 = 0.88; n = 6). The levels of monomeric xyl released during brewing were also related in a linear way (R-2 = 0.92; n = 6) to the beta-D-xylosidase activities. The levels of monome ric ara released were not directly related to alpha-L-arabinofuranosid ase activities (R-2 = 0.28; n = 6). (C) 1997 Academic Press Limited.