| 摘要 |
1,274,678. Xanthohumols. BUSH BOAKE ALLEN Ltd. 13 Nov., 1969 [19 Nov., 1968], No. 54875/68. Heading C2C. [Also in Division C6] In preparing bittering adjuncts for beer involving (a) preparing a solvent extract of hops containing the hop resins and oils, (b) separating the extract into an α-acid-containing fraction, which is substantially free from #-acids and hop oils, and a #-acid- and oil-containing fraction which is substantially free from α-acids, and (c) isomerizing the α-acid-containing fraction, xanthohumols are separated from the solvent extract of hops prepared in step (a) before proceeding to step (b). Thus, a benzene extract of hops is taken up in petroleum ether and the xanthohumols are extracted with 70-80% v./v. of aqueous methanol at a pH insufficiently high to extract the α-acids also. The methanolic extract yields a resinous residue rich in xanthohumols. It is stated that xanthohumols and isoxanthohumols, being insoluble in both hydrocarbon and aqueous alkali would entrain a significant proportion of the valuable α-acids during the solvent extraction process. Part of the xanthohumol then remains in the extract and tends to cause cloudiness on addition to beer. The isomerized extract resulting from step (c) typically contains 10-70% by weight of iso-α-acids as their salts, less than 0À2% of xanthohumols and 20-85% of water. Specifications 1,161,787 and 187,789 are referred to. |
