Preparation of iso-alpha-acid-containing hop extracts
AssigneeAlbright & Wilson Limited
InventorsAnthony M. Humphrey, Anthony Lewis
Life of this patent
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Abstract
When preparing hop extract containing iso-alpha-acids, improved yield of iso-alpha-acids is obtained by contacting a solution of extracted alpha-acids in a water-immiscible non-polar liquid with a sufficiently strong aqueous solution of acid to provide a pH of less than 1 in an aqueous phase that separates from the non-polar liquid. After contacting with the acid, the alpha-acids are isomerized such as by forming alpha acid salts and heating the salts.
Claims23
In the method for the preparation of an isomerized hop extract which consists essentially in extracting alpha-acids from hops with a solvent for alpha-acids to form an alpha-acid-containing hop extract, contacting a solution of said alpha-acids in a water immiscible, non-polar liquid with a base selected from the hydroxides and carbonates of sodium and potassium whereby said base and said alpha-acids react to form salts of the alpha-acids, heating said salts to effect isomerisation thereof, and transferring said isomerised salts, into an aqueous, alkaline phase, the improvement which consists in that a solution of the alpha-acids in a water immiscible non-polar liquid is contacted, prior to conversion into the salt form, with a sufficiently strong aqueous solution of acid to provide a pH of less than 1 in an aqueous phase that separates from said water-immiscible non-polar liquid after contacting said solution of alpha acids with said aqueous solution of acid.
A method for the preparation of isomerised hop extract which consists essentially in contacting a solution of an alpha-acid-containing hop extract in a non-polar, water-immiscible liquid having a boiling point greater than 100.degree. C. with a sufficiently strong aqueous solution of acid to produce an aqueous phase after said contacting having a pH of less than 1, separating said aqueous phase from said liquid, contacting said liquid with a substantially anhydrous base selected from the group consisting of the hydroxides and carbonates of sodium and potassium to precipitate salts of the alpha-acids, heating said salts in said liquid at a temperature between 100.degree. C. and 150.degree. C., to form salts of iso-alpha-acids, contacting said salts of iso-alpha-acids with sufficient water to dissolve them at a pH between about 8 and 9.5, and separating an aqueous solution of iso-alpha-acid salts from said liquid.
A method for the preparation of isomerised hop extract which consists essentially in extracting hops with a volatile solvent for alpha acids, evaporating said solvent to form a hop extract containing alpha-acids, beta-acids and hop oils, dissolving said extract in a water-immiscible non-polar liquid contacting said extract in said liquid with a sufficiently strong aqueous solution of acid to produce an aqueous phase that separates from said liquid having a pH below 1, separating said aqueous phase from said non-polar liquid, contacting said liquid with sufficient substantially anhydrous potassium carbonate to form potassium salts of said alpha-acids, but not to form potassium salts of said beta-acids, heating said salts while in said non-polar liquid to isomerise said salts of said alpha-acids to form potassium salts of iso-alpha-acids, contacting said isomerised salts in said non-polar liquid with sufficient water to dissolve said salts of iso-alpha-acids at a pH insufficient to convert said beta-acids to the salt form, and in the presence of sufficient non-polar, water-immiscible liquid to retain said beta-acids in said non-polar liquid, and separating said liquid from an aqueous phase containing said iso-alpha-acid salts.
A method for the production of isomerised hop extract which consists essentially in contacting a solution of hop extract containing alpha-acids in a non-polar, water-immiscible liquid with a sufficiently strong aqueous solution of acid to provide an aqueous phase having a pH of less than 1, separating said aqueous phase from said liquid, contacting said liquid with sufficient aqueous alkali to extract said alpha-acids from said liquid as their salts, separating said aqueous alkali containing said salts from said liquid and subsequently isomerising said alpha-acid salts.
Dependencies are inferred from the claim text.