| 摘要 |
<p>The hops extract contg. alpha-acids or a soln. of these in a non-water miscible solvent is contacted with an essentially non-aqs. alkali to form resinous alkali metal salts of alpha-acids, or a non-aq. soln. of these. The salts are heated to form iso alpha-acid salts which are recovered by partitioning between a substantially non-polar water-immiscible solvent and water at pH 8.2-9.5. In a specified process is above, a solvent soln. of hops extract is used with alkali not exceeding 140% of the stoichiometric amt. based on the alpha-acids, pref. 105-140%. For prepn. of a bittering agent for beer, hops is extracted with a volatile solvent, the solvent is evaporated from the extract, followed by treatment of the extract as above and sepn. of the aq. soln. of iso alpha-acid salts. In the aq. extn., the amt. of water used is a specific variation is sufficient to dissolve the iso-alpha-acid salts, but insufficient to convert a substantial amt. of beta-acids into their alkali metal salts. Used in making beer. Process enables prepn. of a prod. free of undesirable beta-acids. The use of anhydrous alkali enables lower working volumes giving improved productivity with a simple, fast and complete sepn. by final water washing.</p> |
