process for the production of hopfenextrakten

摘要

1,161,787. α-Acids, humulones and isohumulones. BUSH BOAKE ALLEN Ltd. 15 Nov., 1966 [17 Nov., 1965], No. 48866/65. Heading C2C. [Also in Division C6] A bittering additive comprising α-acids substantially free of fixed oils, essential oils and lupulones and a kettle additive comprising lupulones and essential oils substantially free of fixed oils are prepared, the α-acids in the bittering additive are converted into isohumulones, the kettle additive is added to wort and subsequently, e.g. after fermentation, the isomerized bittering additive is added. A solution of a solvent extract of hops in a waterimmiscible solvent, which dissolves alkali metal humulate salts less readily than does water, is contacted with alkali to form a mixture having a final pH sufficient to transfer the α-acids into the aqueous phase as humulate salts but not sufficient to transfer the lupulones into the aqueous phase as lupulate salts, the aqueous phase containing the humulate salts is separated, the humulate salts are subsequently isomerized to give isohumulones substantially free of fixed oils, essential oils and lupulones and, before or after isomerization, the respective humulate or isohumulate salts are separated from a liquid aqueous phase. The hop ingredients remaining in the water-immiscible solvent used in the initial partitioning are recovered after separation from the aqueous phase and freed from any fixed oils and hop waxes by re-dissolving in 80-95% aqueous methanol, whereby there is obtained a kettle additive comprising lupulones and essential oils substantially free of fixed oils. According to one typical example, ground dried hops were extracted and treated according to the above process. The residual aqueous solution of the potassium salts of the humulones was diluted with water to produce a tractable solution containing 30% W/V total solids, was boiled for approximately 45 minutes to effect isomerization and then concentrated by vacuum distillation to a soft extract containing 10-20% of water. The soft extract was dried under vacuum to a dry powdered product containing from 40 to 60% of isohumulones.