DE1442159C - Process for the practically selective separation of alpha acids and beta acids from hops extract obtained by means of organic solvents as alkali salts - Google Patents

Description

Hopping wort with natural hops presents the brewer with the problem of making beer with practical to produce a consistent taste, although the hops as a natural product are not uniform and often has to be stored for a long time before use, since hops are only harvested once a year, beer but is brewed continuously. However, long storage is disadvantageous for the quality of the hops. In addition, with the hops, substances that are undesirable for the taste of the beer are sometimes created introduced into the wort.

To avoid the difficulties and disadvantages associated with using natural hops, Attempts have already been made to hop wort with extracts made from hops; With With extracts, however, the beer cannot taste as good as with natural hops, and there As the extracts are usually syrupy, they cannot easily be immersed in the wort evenly distribute. It has also been found that the extracts do not remain stable. It is also known to produce various types of extracts from hops in order to produce special components such as oils, Separate tannins and acids. These extracts have limited use as they are not make it possible to achieve the desired taste of the beer.

The invention is based on the object, the alpha acids and beta Säuien from by means of organic Solvent-obtained hop extract pi Aktisch selectively to be separated as alkali salts, the enable the brewer to stop using natural hops or extracts for hops difficulties associated with beer wort without affecting the taste of the beer is affected, but is even improved if one compares beer with the made using natural hops. The brewer now has it in the Hand, the products of the beer wort obtained by the method of the invention in each desired amounts during a process stage in the beer production to add in which they can be most effectively used to achieve a beer with a predetermined taste. Aromatic and bacteriostatic properties of the can be determined with the process products Achieve beer to a controllable extent.

These products also facilitate the continuous production of beer, something with natural hops is quite difficult.

According to the process of the invention, the alpha-acids and alpha-acids are separated in a practically selective manner the beta acids from hops extract obtained by means of organic solvents as alkali salts in the way that you can use the solvent extract with one on the alpha acids. related practically stoichiometric Amount of aqueous alkali metal hydroxide solution added, the aqueous solution of the alkali metal salts formed separates the alpha acids from the solvent extract after the separation of the aqueous Solution remaining solvent extract in turn mixed with an aqueous alkali hydroxide solution, separates the aqueous solution of the formed alkali metal salts of the beta acids and finally from the aqueous Solutions of the alkali salts of alpha acids or beta acids by removing the water solid salts isolated.

It is surprising that a selective separation of the alpha and beta acids only with the help of a aqueous alkali solution is possible, as one would expect due to the similar structure of both acids it had to be that a mixture of acids is formed when the extract is completely mixed with one Neutralization of the acids treated insufficient amount of an alkali solution.

From the Austrian patent specification 215 930 it is known that beer wort is made from isohumulone by reduction with a metal hydride such as sodium borohydride, potassium borohydride or by means of hydrogen and add sodium isohumulol obtained in alcohol to increase the lightfastness of the beer increase, a task that only arises when beer is sold in light-colored bottles, which is practical not happening. Since the method of the Austrian patent specification is initially based on a humulone, that from an organic solvent

obtained hops extract is obtained as a lead complex, isohumulol is used in many Countries contrary to legal regulations, apart from the fact that the. Way to obtain the isohumulol is much more complicated than the preparation of the alkali salts of the alpha- and beta-acids according to the method of the present invention.

The hop extract used for the purposes of the invention can be made from ground or whole, dried hops, fresh hops (green hops), frozen hops and lupulin, fresh or dried, can be obtained.

It is advantageous for the separation of alpha-acids to use a Alkalihydroxydmenge which is up to 10 ° / ₀ over the stoichiometrically required amount.

According to a further embodiment of the invention to separate the alkali salts of the alpha acids, the required alkali hydroxide solution is added Partial amounts are added and the respective resulting solution of the alkali salt is separated off.

If the alkali hydroxide solution is added to the solvent extract at a temperature not exceeding 50 °, practically only the alpha acids are obtained; however, if one puts the solvent extract with Alkälihydroxydlösung at 50 ⁰ C temperature exceeding, one obtains mixtures of alpha-acids and isohumulones.

Sodium hydroxide is preferably used as the alkali hydroxide solution.

The invention is described below with reference to the flow diagram shown in the drawing.

I. Solvent extraction

Hops are treated with a solvent that extracts the <x and / J acids. The hops are preferably in a ground form in order to obtain a more efficient extraction of the desired constituents. The preferred solvent is hexane. However, other solvents such as toluene and chloroform can also be used. For the sake of simplicity, the process of the invention is described below using hexane as the solvent. As a result, the first stage of the process is a hexane extraction stage 1, as can be seen from the flow diagram. Two fractions are formed by means of this hexane extraction, namely a hexane extract and a residue. The residue 2 and the hexane extract 3 are then in a suitable manner, e.g. B. by filtration, separated from each other.

II. Residue Treatment

The residue 2 containing water-soluble components is mixed with hot water in a water extraction stage 4 treated, whereby the water-soluble tannins 5 are extracted from the residue. The tannins are then freeze-dried in a drying level 6 or another equivalent technical method, by which the heat-unstable tannins are not affected. The dried tannins 7 are in in a stable form and are available for incorporation in suitable quantities in custom-made products Mixtures available for use by the brewer.

III. Hexane extract treatment

The amount of Λ-acids and ^ -acids contained in the hexane extract 3 is then calculated and for one of the standard test methods is used for this purpose. The actual test method used is the spectrophotometric used in "Methods of Analysis of the American Society of Brewing Chemists", 6th revised edition, 1958, pp. 138-A, 138-B, 138-C.

The hexane extract is then treated with alkali in successive stages as follows:

a) First alkali treatment.

The hexane extract is in an alkali treatment stage8 with "an aqueous sodium hydroxide in an acid based on the calculated amount" "Alkali solution containing a stoichiometric amount. This treatment gives a mixture a) an aqueous extract 9 containing the sodium salts of the «acids; and b) a hexane solution 10, which is practically free from α-acids. The alkali extract 9 is then made up of the hexane solution any suitable manner, e.g. B. by means of a separatory funnel, separated, and the extract 9 is in a dry stufeil dried to by freeze drying to obtain a powder 12 "which contains a high content of sodium salts of the" acid Freeze drying is used because the salts are not stable in heat. Another a suitable drying method is evaporation under vacuum. ■

The dried "- acid sodium salts 12 are in a stable form, and they can be in suitable Quantities of the wort during an appropriate treatment stage of the brewing process can be added.

, \ b) Second alkali treatment

The hexane solution 10, which contains the x-acids are removed, is then in a second alkali treatment stage 13 treated with an aqueous alkali solution, preferably based on sodium hydroxide to the calculated amount of the amount / I-acids present in the hexane extract, in stoichiometric Amount contains, whereby the solution is applied in such a concentration to get out of the hexane solution to deposit the / I acids in the form of their sodium salts. There is a mixture; from a) one aqueous alkali extract 14, which contains the ß-acid sodium salts and b) one of «acids and ^ acids practically free hexane solution 15. The alkali extract 14 is then suitable from the hexane solution Way, e.g. B. by means of a vaginal funnel, deposited, and the alkali extract is in a drying stage 16 dried to obtain a powder 17 with a high content of / 3-acid-sodium salts.

The same drying technique as described above can be used for Obtaining the powdered> acid is followed.

The dry ß-acid sodium salts are more stable Form before, and they can be in suitable amounts of the wort or the beer during any suitable Be added stage of the brewing process.

IV. Treatment of the hexane solution

The hexane solution is then subjected to fractional distillation in a destination stage 18, hop oils 19 and hexane 20 are obtained.

The hop oils are available to be made in appropriate quantities in accordance with customer requirements Mixtures to be used by the brewer. If desired, according to the procedure the invention obtained free acids of the -acid salts and the / 5-acid salts by neutralizing the Salts are obtained. As particularly illustrated in the flow diagram of the drawing, the α-acid salts 12 and the /? - acid salts 17 by acidification are neutralized, the free α-acids 12 'and the free / 3-acids 17' are obtained as Such can be applied after turning them into a stable form. has convicted.

When determining the stoichiometric amount given in the following examples, the complex nature of the mixture known as -acids and the presence of small amounts of extraneous acidic ones Substances charged. The stoichiometric amount of sodium hydroxide was increased as a result based on the molecular weight of humulone and added 10% excess sodium hydroxide.

B ei s ρ i el I

1000 g dry hops (7.41% acids, 5.53% acids according to the A.S.B.C. ([American Society of Brewing Chemists] test method) were ground to a powder and stirred with hexane extracted for several hours and filtered. The procedure was repeated twice and the combined Hexane extracts distilled in vacuo to a volume of 3000 ml. The solution contained 5.5% solids (total 166.5 g); the solids contained 45.60% acids by the A.S.B.C. test method . and 29.17% ^ acids.

180 ml of the aforementioned hexane solution contain 10 g of total solids, 4.56 g of α-acids and 2.91 g /? - acids. The equivalent amounts of normal sodium hydroxide to these acids are:

«Acids 12.6 ml

ίο / 5-acids 7.0 ml.

A) The 180 ml hexane solution was mixed with 13 ml normal sodium hydroxide and 25 ml water and the mixture stirred at 25 ° C for 10 minutes, deposited, and the hexane layer was washed with 10 ml of water. The combined water extracts were freeze-dried Subjected by freezing in a dry ice-acetone bath and under high

ao vacuum dried.

B) 7.0 ml of normal sodium hydroxide were added to the hexane solution remaining from extraction A and 15 ml of water are added and

as the extraction, washing, separation and the Freeze drying, as described under A, carried out.

Q 7.0 ml of normal sodium hydroxide were added to the hexane solution remaining from extraction B and 15 ml of water are added and the process as described under A is repeated.

The test results are summarized in the following table:

Weight
dry α-acids
% ^ Acids
^e /. % Yield
α-acids % Yield
, / 3 acids A.
B.
C. 5.0 g
2.6 g
1.2 g 83.4
0
0 0
80.0
42.6 91.4 71.5
17.5 All in all 8.8 g 91.4 89.0

This example illustrates the accuracy of the separation achievable by the method of the invention, likewise the fact that excellent yields, especially with regard to the -acids, are obtained can be.

Example II

180 ml of the hexane solution prepared according to Example I were, as indicated in Example I, extracted with parts of dilute sodium hydroxide, as in Example I, but the extractions were carried out at a temperature of 45.degree.
At 45 ° C the yield and purity of the -acids are superior to those at 25 ° C. This is due in part to the greater ease of separating the two layers at the higher temperature. The overall yield of / 9 acids is lower at the higher temperature. Under these test conditions, little or no isomerization of the α-acids to isohumulones occurs.

The test results are summarized in the following table:

Weight
dry «Acids
7th /? - Acids
% "/" Yield
«Acids % Yield
// - acids Λ
H
C. 5.0 g
2.85 g
1.3 g 87.07
0
0 0
71.66
16.24 95.2 70.0
7.2 liisj! C ".ainl », 15 g 95.2 77.2

Example III

180 ml of the equivalent in previous examples The hexane solution produced was evaporated to dryness under high vacuum. That way Thus obtained 10 g of material was dissolved in 180 ml of VMP naphtha. The extractions of this solution

with aliquots of diluted alkalis were carried out as indicated in Example I, but "the Extractions were carried out at a temperature of 90 ° C. The resulting solutions were as in the preceding Examples subjected to cold drying. In the following table are the test results summarized:

Weight
dry α-acids
Vo /? - acids
% 7 “Yield
ot acids % Yield
/ 3 acids A.
B.
C. 4.8 g
1.7 g
2.2 g 45.6
0
0 0
23.6
33.2 48 13.7
25.1 All in all 8.7 g 48 38.8

From the above figures it can be seen that there has been no loss of weight of the material, but a considerable loss of α- and / S-acids. The determinations of the α- and / S-acids in this as well as in all examples were according to the official A.S.B.C. method. The spectrophotometric curves obtained after the A.S.B.C. method indicated that isohumulones were present. R i g b y and bars (A. S. B. C. proceeding 1961, 46-50) describe a method for the determination of α-acids and isohumulones. Your method applied to faction A produced the following results:

Weight
G α-acids
° / o Isohumulones ° / o yield of α-acids and isohumulones A. 4.8 52.1 22.7 84.2

It follows from the above figures that a high degree of isomerization had occurred at 90 ⁰ C during the relatively short period of extraction. The experiment represents, at least in part, an isomerization of -acids under buffered conditions in which the ß- and other hop acids act as buffers to prevent overbasing. The experiment also shows that the acids containing isohumulones, like their sodium salts, can be dried by deep freezing without decomposition.

Example IV

300 g of ground hops were extracted three times with hexane while stirring at room temperature and filtered each time. The extracts were combined and placed in a vacuum to a volume of 1000 ml distilled.

According to the A. S. B. C. investigation method of hops, a calculation resulted in 22.23 g of α-acids, the 60 ml normal sodium hydroxide are equivalent.

The hexane solution was stirred with 50 ml normal sodium hydroxide plus 50 ml water for 10 minutes. The aqueous part was separated off and the hexane was extracted with 16 ml of normal sodium hydroxide plus 20 ml of water repeatedly. The aqueous part was separated off and the hexane with 40 ml of water washed. The aqueous portions were combined, filtered and dried by cold.

The weight of the dry material was 26.0 g (A.S.B.C. method).

«-Acids 79.5%

^ -Acids 0.4%

This corresponds to a 93% yield of the α-acids contained in the hops.

The sodium salt obtained as indicated above was dissolved in water, the solution acidified and then extracted with ether and the ether extract dried. There was obtained a yield of 93.7 ° / ₀ of free acids in the form of a thick oil. This material had a specific rotation of -180 °. Humulon has a specific rotation of -225 °. The optical rotation and the spectrophotometric test method are therefore practically in agreement.

The amount of sodium contained in the sodium salt determined by an experiment was 6.04%, which agreed well with the 93.2% free acid obtained.

The hexane solution extracted with alkali was further extracted with dilute sodium hydroxide, until no more extractables remained in the hexane. The hexane solution was made with water washed free of alkali and then distilled through a fractionating column to a volume of 60 ml. The 60 ml was then concentrated in vacuo to 20 ml or less until constant Weight has been reached. The material thus obtained was extracted with 90% methanol and the methanol extract concentrated in vacuo to 20 ml or less and a yield of 2 g of a thick oil obtained, the beer as such or after a further treatment Gives the aroma of hops.

The starting hops extracted with hexane were dried in air to remove the hexane and then by treatment with 600 ml of hot

309 62 on 7th

ίο

65 ° C held water extracted for 16 hours, filtered and washed with hot water. The temperature was kept at 65 ° C to be microbiological To prevent growth. All of the water extract thus obtained became dried by freezing and gave a yield of 52.8 g. This material contains all water soluble Hop tannins and is a valuable addition to the wort to avoid the so-called "hot stroke" to create.

Example V

180 ml of the hexane solution prepared according to Example I together with 4.56 g of α-acids and 2.91 g of α-acids (A.S.B.C. test method) were treated with an amount of dilute sodium hydroxide equivalent to that of Total amount of hops acids present was equivalent. This hexane solution was 10 minutes stirred with 27 ml of normal sodium hydroxide and 55 ml of water at 25 ° C. The aqueous portion was separated, filtered and dried by freezing.

Weight of dry material - 8.2 g A. S.B. C. test method,

α-acids 34 ° / ₀

/ 9 acids 31%

This corresponds to a yield of only 61% of the originally present α-acids and a yield of 89% of the / 3 acids. In Example I, according to which the same total amount of sodium hydroxide was used, the yield of the α-acids was 91.4%. This illustrates that a considerable Decomposition of the α-acids takes place in the presence of alkali. However, the experiment did not show that under any considerable amount of isohumulones formed in the wild under the above test conditions, because there was obviously no separation of the α-acids from the ίο den / 3-acids.

Example VI

360 ml of a hexane extract from hops which, according to the A. S. B. C. test method, 8.88 g of α-acids and 6.63 g /? - acids were added with stirring treated with an amount of dilute sodium hydroxide equivalent to 2.7 g of alpha acids. It was deposited and the treatment with further equal amounts of dilute sodium hydroxide to repeated four extractions. The aqueous extracts were dried by themselves by freezing.

For each extraction 8 ml normal sodium hydroxide and 20 ml water were used. The dried ones Samples were tested according to the A.S.B.C. test method. In the following table are the test results summarized:

pH of the solution Weight
dry «Acids
% /? - acids
7o % Yield
α-acids A.
B.
C.
D. 8.15
8.5
9.25
10.5 2.0
3.3
3.4
3.2 89.1
88.2
72.7
30.0 0
0
0
53.5 20.0
32.7
27.9
10.8 total 11.9 91.4

This example shows that the α-acids are selectively extracted when small amounts of alkali are used will. It should be noted that the pH of the extracts over a fairly large Range extends without giving any indication of the relative amount of extracted alpha-acids given is. It is shown in Examples I, II and IV that over 90% of the α-acids and none of the? -Acids extracted according to the A.S.B.C. test using appropriate amounts of sodium hydroxide can be.

Example VII

180 ml of the hexane extract of hops prepared according to Example IV were diluted with amounts Alkali extracted according to Example I, with the difference that instead of sodium hydroxide normal potassium hydroxide has been used.

The results were as follows:

Weight
G α-acids
7th / J acids
7o % Yield
α % Yield
ß A.
B.
C. 5.3
2.8
1.5 76.4
8.8
0 0
59.3
40.8 80.0
5.4 57.0
20.7 total 9.6 85.4 77.7

The result illustrates that potassium hydroxide is somewhat less effective than sodium hydroxide in separating x- and ^ -acids under otherwise identical conditions.

Example VIII

180 ml of the hexane extract prepared according to Example I. of hops were diluted with amounts

Sodium hydroxide treated in the same way as indicated in Example I, but the extractions were carried out at 65 ° C and the following results were obtained:

Weight
G α-acids
⁰ U ^ Acids
7o % Yield
rt % Yield
ß A.
B.
C. 4.9
2.2
1.2 75.5
3.27
0 0
44.18
56.17 79.0
1.5 54.8
38.0 total 8.3 80.5 92.8

This experiment shows that the yield of α-acids at 65 ° C is not as good as at 45 ⁰ C. The spectrophotometric curves show that about 10 ° "of the originally present α-acids have been converted to isohumulones ao /.

Example IX

1000 ml of a usual, not with as Brewing wort added to hops, 100 mg of the material obtained according to Example IV was added. This According to the A.S.B.C. test method, it contained 79.5 mg of α-acids and 0.4 mg /? -acids, which is 1160 mg of hops per liter of wort is equivalent. The treated wort was refluxed for 5 hours, cooled and a filtered sample examined by the Rigby and Bars method (A.S.B.C. method 1961, 46-50).

A sample of the same wort was treated with 1160 mg hops per liter of wort and taken in the brewery cooked, and analyzed in the same way.

The wort treated in the laboratory gave:

45.6 ppm isohumulones,
16.0 ppm alpha acids.

The wort treated in the brewery resulted in:

28.3 ppm isohumulones

10.4 ppm α-acids.

The example described above illustrates that the loss of bitter substances on transition of hops into the wort is considerably lower if the α-acids according to the method of the present results finding have been extracted.

Example X

In example III it was noted that isomerization has taken place and the fraction A after the test method Rigby 23.7 ° / ₀ containing isohumulones as well as 45.6 J ⁰ ₀ α-acids in accordance with test method ASBC.

3.0 g of fraction A obtained according to the experiment of Example III, the 1.370 g of α-acids and Containing 0.715 g of isohumulone was dissolved in water, acidified with hydrochloric acid and divided into three parts extracted from 50 ml of hexane each time. The hexane solution obtained in this way was shaken with Water and separation freed from free hydrochloric acid. The hexane extract was 10 minutes with 3.3 ml Stirring normal sodium hydroxide plus 10 ml of water. After the separation, the hexane was 5 ml Water washed. The combined water fractions were filtered and dried by freezing.

The extraction and the deposition were carried out with a further amount of 3.3 ml normal sodium hydroxide and 10 ml of water repeatedly and another 5 ml of water used for washing. The combined extracts were also filtered and cold dried.

The amount of sodium hydroxide used for each extraction was equivalent to 1.2 g of α-acids (or isohumulones).

The analysis of the dry sample is given below:

1
2

Weight
G

1.2
1.2

% α-acids
ASBC test method

26.83
54.50

Rigby test method

37.70
11.46

This experiment shows that the isohumulones extracted preferentially by dilute sodium hydroxide be, but the separation is not exactly what follows from the fact that in faction 2 something Isohumulones are present.

45

Example XI

A hexane extract from hops which, based on the ASBC test method, had 2.53 _{% / 0} α-acids and 1.62% / 3-acids, was left to stand in a flask which had been exposed to diffuse daylight for 6 weeks. A filtered sample then contained:

1.48 ° / ₀ α-acids in accordance with the test method ASBC 0 ° / _0/3 acids according to the test method ASBC

1.46 ° / ₀ isohumulones according to the test method Rigby

An amount of 180 ml of the above solution containing 2.66 g of α-acids according to the A.S.B.C. test method and 2.63 g Containing isohumulones according to the Rigby test method were treated with 8 ml of normal sodium hydroxide for 10 minutes and 15 ml of water were stirred, then it was separated out and the hexane solution was washed with 5 ml of water. The aqueous components were combined, filtered and dried by freezing. The hexane solution was then treated in the same way with a further amount of 8 ml of sodium hydroxide.

The following analytical results were obtained:

Weight
g

2.1
3.8

° / o α-acids
ASBC test method.

9.0
40.9

° / o isohumulones

Rigby test

method

55.1
19.2

This experiment shows that mixtures of -acids and isohumulones can be separated if also not as precise as mixtures of «- and / 3 acids.

The hops constituents obtained according to the process of the invention are used to produce malt beverages and of alcoholic and non-alcoholic malt beverages. The alpha-

Acids and beta acids either in powder form, i.e. H. in the form of their alkaline salts, or in oil form, d. H. in the form of free acids, which will hold eggs when the salts are acidified. The free acids can dutch absorption of inert materials can also be brought into powder form. The free acids can be mixed with suitable Materials such as maltosedextrin can be encapsulated.

The alpha acids, be it in the form of their salts or as

ίο free acids, foods can also be used as flavorings can be added. The beta acids can be in the form of their salts or as free acids as bacteriostatic agents are used for food.

The exploitation of the invention can be through legal provisions, in particular through the food law or by the Beer Tax Act.

1 sheet of drawings

Claims (6)

Patent claims: 1. Process for the practically selective separation of the alpha acids and the beta acids from hops extract obtained by means of organic solvents as alkali salts, characterized in that that the solvent extract with a practically stoichiometric amount of aqueous alkali metal hydroxide solution based on the alpha acids added, the aqueous solution of the formed alkali salts of the alpha acids of separates the solvent extract, the remaining after the separation of the aqueous solution Solvent extract in turn mixed with an aqueous alkali metal hydroxide solution, the aqueous solution separates the formed alkali salts of the beta acids and finally from the aqueous solutions of the Alkali salts of alpha acids or beta acids isolate the solid salts by removing the water. 2. The method according to claim 1, characterized in that an amount of alkali metal hydroxide is used for the separation of the alpha acids which is up to 10 ° / ₀ above the stoichiometrically required amount. 3. Process according to Claims 1 and 2, characterized in that one is used for the deposition the alkali metal hydroxide solution required is added in partial amounts to the alkali metal salts of the alpha acids and separating the resulting solution of the alkali salt. 4. Process according to claims 1 to 3, characterized in that the solvent extract is mixed with the alkali metal hydroxide solution at a temperature not exceeding ^{50 ° C.} 5. Process according to claims 1 to 3, characterized in that the solvent extract mixed with the alkali hydroxide solution at a temperature exceeding 50 ° C. 6. Process according to Claims 1 to 5, characterized in that the alkali metal hydroxide " solution uses aqueous sodium hydroxide solution.