HOPS

摘要

1,236,731. Hop extracts. WATNEY COMBE REID & CO. Ltd. 7 Jan., 1970 [9 Jan., 1969], No. 1393/69. Heading C2C. [Also in Division C6] The alpha acids and beta acids are extracted from resinous hop material such as lupulin in the following process steps: (1) (optional) the hop material is given an initial wash with sodium or potassium hydrogen phosphate buffer solution of pH 4-9to extract selectively tannins and fatty acids, the temperature being kept low enough to avoid substantial dissolution of the alpha acid content of the hop fraction; (2) the alpha acids are then extracted with the aid of aqueous disodium or dipotassium hydrogen phosphate, or sodium or potassium citrate, at a pH in the range 7 to 9 and a temperature between 40‹ and 90‹ C.; and (3) the beta acids are extracted from the residue with a 0À2-2À0% by weight aqueous solution of sodium or potassium carbonate at a temperature in the range 25‹ to 100‹ C. Crystallization of the extracted alpha acids and beta acids may be promoted by the addition of acid, e.g. citric acid and gaseous carbon dioxide, respectively. The extractions may be performed by percolating alkali through a column of the lupulin-rich powder or by spraying the alkali on to the inside surface of a packed bed of the powder in a basket centrifuge. In both cases a filter aid (specified) should be included. The extracted alpha acids may be isomerized by boiling at atmospheric pressure for 2 hours at a pH of 9 (or longer at a lower pH). The extracted beta-acids may be oxidized to hulupones by gaseous oxygen at a temperature in the range 70-90‹ C.