Corn. plant enzymes peroxidases extd. from horseradish (Armoracia rusticana), carrot (Daucus carota), sugar beet (Beta vulgaris), parsley (Petroselinum crispim) and apple (Malus mill) were added to the hop ext. (prepd. by extn. with supercrit. CO(2)) to degrade humulones and lupulones contained in the ext. at pH 5.4-8.2 (phosphate buffers). The highest degrdn. efficiency was achieved when the horseradish enzyme extract was used. After 72 h at 25 degrees C, the total degrdn. of all hop bitter acids was obsd. The pH did not play any important role in the degrdn.