GB1088631A - Hop concentrate - Google Patents

Abstract

In a method for preparing solvent extracts of hops, wherein hops are contacted with an extracting solvent (benzene, light petroleum, acetone, methanol or carbon tetrachloride) to form a crude extract, the solution is separated from insoluble matter and the crude extract recovered, the crude extract so obtained is contacted with a purifying solvent consisting of from 80 to 90% by volume methanol, from 80 to 90% by volume ethanol or 80 to 90% by volume of a mixture of methanol and ethanol, and from 10 to 20% by volume water, at a temperature of from 0 to 50 DEG C. in an amount sufficient to dissolve a part of the crude extract, thereby forming a solution of a purified extract, the solution of the purified extract is separated from the undissolved part of the crude extract and the purified extract is recovered. The crude extract may be contacted with absolute methanol and the water added subsequently. The purified extract typically contains 82-94% soft resins, including a total humulones content of 25-55%, a total lupulone content of 10-40%, 1-4% essential oil of hops and up to 2% water. The purified extract may be dissolved in a water immiscible solvent (benzene, light petroleum or carbon tetrachloride) and the solution contacted with 2-20% w/v potassium or sodium hydroxide to form an aqueous solution (pH 10.7-12) of an alkaline extract, the aqueous phase being separated from the water-immiscible phase and heated to isomerize the humulones in the alkaline extract. Carbon dioxide may be passed through the solution of the alkaline extract before and/or during the heating, such heating may involve boiling the solution at atmospheric pressure for at least one hour, and the solution of the isomerized extract produced may be concentrated or dried. The purified extract may be rendered dispersible by blending with 100 parts by weight of the extract, 2.5 parts of 5% aqueous methyl ethyl cellulose, 2.5 parts of a 5% aqueous sodium carboxymethyl cellulose solution and 2.5 parts by weight of glucose syrup (70% glucose w/v in water).