Method for the reduction of aroma loss during the production of ethanol-reduced and ethanol-free beverages

Abstract

The present invention relates to a method for the reduction of aroma loss during the production of ethanol-reduced and ethanol-free beverages.

Claims

1. A method for the reduction of aroma loss during the production of ethanol-reduced and ethanol-free beverages comprising the steps: (a) de-alcoholization of a beverage containing from 1 to 60 vol.-% ethanol by a thermal or membrane-based dealcoholization process; (b) separating the ethanol containing process stream from the de-alcoholized beverage; (c)(i) conveying the separated ethanol containing process stream to a condenser, at least one stripping column and subsequently to at least one adsorber column, or (ii) conveying the separated ethanol containing process stream directly to at least one adsorber column; wherein the ethanol containing fraction of the ethanol containing process stream is adsorbed on the at least one adsorber column; (d) recycling of the remaining process stream to the de-alcoholized beverage.

2. The method according to claim 1, wherein the adsorber material of the at least one adsorber column comprises an MFI zeolite and/or a silicalite with a molar SiO2/Al2O3 ratio of at least 200.

3. The method according to claim 1, wherein the beverage has a temperature of from 5 to 20° C., the ethanol containing process stream has a temperature of from 15 to 40° C. and the temperature within the at least one adsorber column is from 20 to 65° C.

4. The method according to claim 1, wherein the adsorption according to step (c) (i) or (ii) is conducted at a pressure of from 0.5 to 2 bar.

5. The method according to claim 1, wherein the conveying of the ethanol containing process stream of step (c) is carried out at a flow rate of from 50-950 (L/hour)/L adsorber volume.

6. The method according to claim 1, wherein step (a) is carried out as a two-stage step and wherein a process stream 1 is obtained which is the ethanol containing process step subjected to method steps (b) to (d) and wherein a process stream 2 is obtained which is discarded.

7. The method according to claim 6, wherein the volumetric ratio of process stream 1 to process stream 2 is selected from the range of from 0.01 to 1.

8. The method according to claim 1, wherein the ratio of the ethanol containing process stream to the de-alcoholized beverage is selected from the range of from 5 to 20 vol.-%.

9. The method according to claim 1, wherein the ethanol containing process stream contains from 10 to 90 vol.-% ethanol, from 10 to 90 vol.-% H20 and from 50 to 200 mg/l aromatic compounds.

10. The method according to claim 1, wherein the dissolved oxygen level of the beverage according to step (a) is selected from a range of from 0.01 to 3.0 mg/l.

11. The method according to claim 1, wherein step (c) is repeated at least once.

12. The method according to claim 1, wherein steps (c) and (b) are repeated at least once.

Description

EXAMPLES AND FIGURES

[0073] The present invention is explained in greater detail below by means of the examples. It is emphasized that the examples illustrate particular embodiments and do not limit the scope of the present application in any way.

[0074] FIG. 1: shows a flow chart of a set up for conducting the inventive method implementing a step (a) as a two-stage step and implementing condensation of the ethanol containing beverage stream

[0075] FIG. 2: shows a flow chart of a set up for conducting the inventive method implementing a step (a) as a two-stage step but no condensation of the ethanol containing beverage stream

[0076] FIG. 3: shows the ethanol content in the gas stream behind the adsorber column with 80 min cycle time according to example 1

[0077] FIG. 4: shows the ethanol content in the gas stream behind the adsorber column with 20 min cycle time according to example 1

[0078] FIG. 5: shows the results of example 2

[0079] FIG. 6 shows the distribution of aromatic compounds in the beverage, the de-alcoholized beverage and the ethanol containing process stream

[0080] FIG. 7 shows the distribution of aromatic compounds in the ethanol containing process stream, before carrying out step (c) (i) and the remaining process stream after step (c)(i)

[0081] FIG. 8 shows the distribution of acetaldehyde in the ethanol containing process stream, before carrying out step (c) (i) and the remaining process stream after step (c)(i), and in the ethanol containing fraction

[0082] FIG. 9 shows the amount of aromatic compounds, which can be recycled into the dealcoholized beverage after carrying out the inventive process.

[0083] FIG. 10 shows the amount of aromatic compound, that can be recycled into the dealcoholized beverage after the respective process step.

EXAMPLE 1: INFLUENCE OF CYCLE TIME DURING STEP (C) (I)

[0084] 1 L synthetic solution of ethanol and water, resembling the ethanol containing process stream with an ethanol concentration of 5 vol.-% was provided in a tempered (20° C.) container and conveyed by using a peristaltic pump (Watson Marlow, 520DU) into the stripping column (diameter 60 mm, height 1400 mm) at the top of the column with a volume flow of 1.5 L/h. The stripping column was filled with filling material (Teflon raschig rings, diameter 6 mm, height 6 mm, Sigma-Aldrich, Z243477). A counter-currently flowing N.sub.2 stream (20 L/min) was conveyed from the bottom to the top of the stripping column. The stripping column was used at a pressure of 1.013 bar and a temperature of 22° C. The N.sub.2 gas stream was contacted with the adsorber columns and recycled into the stripping column. For adsorption three adsorber columns were used, filled with adsorber material (Clariant, TZP9028; MFI Zeolith, molar SiO.sub.2/Al.sub.2O.sub.3 ratio 1000). Simultaneously two adsorber columns were used for adsorption, one column for desorption. From the N.sub.2 gas stream a sidestream of 0.5 L/min were taken behind the adsorber column and the ethanol content of the gas stream was analysed with a mass spectrometer (Thermo scientific PrimaPro Process MS) for monitoring of the ethanol removal by the adsorber columns. For desorption of the ethanol from the adsorber columns a N.sub.2 gas flow (0.5 L/min) was used. By a vacuum pump the pressure in the adsorber columns was reduced to 100 mbar.

[0085] Two experiments were performed with 20 min and 80 min cycle time respectively when the adsorber columns were switched.

[0086] FIG. 3 shows the ethanol concentration within the gas stream behind the adsorber column and the mode of each adsorber column 1-3 with 80 min cycle time. 0-80 min: Columns ½ in adsorption, column 3 in desorption; 80-160 min: Columns ⅓ in adsorption, column 2 in desorption; 160-240 min: Columns ⅔ in adsorption, column 1 in desorption.

[0087] FIG. 4 shows the ethanol concentration within the gas stream behind the adsorber column and the mode of each adsorber column 1-3 with 20 min cycle time.

[0088] It can be seen from the results of example 1 that the ethanol concentration in the gas stream with a cycle time of 80 min increases after 20-30 min of each cycle resulting in a lower adsorption of ethanol. With 20 min cycles the ethanol concentration in the gas stream is much lower at 0.01-0.025%.

EXAMPLE 2: INFLUENCE OF ETHANOL CONCENTRATION DURING STEP (C)(I)

[0089] 1 L synthetic solution of ethanol and water resembling the ethanol containing process stream with different ethanol concentrations of 5 vol.-%, 15 vol.-%, 30 vol.-% and 40 vol.-% was provided in a tempered (20° C.) container and conveyed by using a peristaltic pump (Watson Marlow, 520DU) into the stripping column (diameter 60 mm, height 1400 mm) at the top of the stripping column with a volume flow of 1.5 L/h. The stripping column was filled with filling material (Teflon raschig rings, diameter 6 mm, height 6 mm, Sigma-Aldrich, Z243477). A counter-currently flowing N.sub.2 stream (20 L/min) was conveyed from the bottom to the top of the stripping column. The stripping column was used at a pressure of 1.013 bar and a temperature of 22° C. The N.sub.2 gas stream was contacted with the adsorber columns and recycled into the stripping column. For adsorption three adsorber columns were used, filled with adsorber material (Clariant, TZP9028; MFI Zeolith, molar SiO.sub.2/Al.sub.2O.sub.3 ratio 1000). Simultaneously two columns were used for adsorption, one column for desorption. For desorption of the ethanol from the adsorber columns a N.sub.2 gas flow (0.5 L/min) was used. By a vacuum pump the pressure in the adsorber columns was reduced to 100 mbar. The experiments were performed with 20 min cycle time.

[0090] FIG. 5 shows the dealcoholization of the different synthetic solutions. The dealcoholization can be fitted by an exponential function c.sub.Ethanol (t)=A.Math.e.sup.−B.Math.t with c.sub.Ethanol as the ethanol concentration at the time t. A as a constant which can be expressed as the ethanol concentration at the beginning of the process and B as a constant describing the ethanol removal. The constants of the fittings and the regression coefficient R.sup.2 of the fitting are shown in table 1.

TABLE-US-00001 TABLE 1 Parameters of the exponential fitting Ethanol Regression concentration A B coefficient R.sup.2  5 vol.-% 243.2 0.068 0.999 15 vol.-% 308.9 0.059 0.997 30 vol.-% 125.7 0.058 0.996 40 vol.-% 34.9 0.072 0.985

[0091] By differentiation of the function the ethanol removal can be described as dc.sub.Ethanol/dt=B.Math.c.sub.Ethanol(t). As can be seen the constant B is the range of 0.58-0.72 independent from ethanol concentration. It can be seen from the results of example 2 that the ethanol removal increases with the concentration resulting in a faster and cost effective inventive process especially at high concentration of the ethanol containing process stream.

EXAMPLE 3: ANALYSIS OF AROMATIC PROFILE

[0092] Conducting a thermal based de-alcoholization, as depicted in FIG. 1, a de-alcoholized beverage and an ethanol containing process stream 1 are produced.

[0093] Aromatic compounds, originally contained in the beverage, are transferred to the ethanol containing process stream during the thermal based de-alcoholization process. This transfer is visualized in FIG. 6. There the aromatic compound distribution of a beverage, as well as the de-alcoholized beverage and ethanol containing process stream that derive from it, are depicted. The following aromatic compounds were measured by the method gas chromatography (Gas Chromatography Headspace with FID Sampler).

[0094] Acetaldehyde

[0095] n-Propanol

[0096] i-Butanol

[0097] 2-Methylbutanol

[0098] 3-Methylbutanol

[0099] Ethylacetate

[0100] Phenylethanol

[0101] 3-Methylbutanoic acid

[0102] Hexanoic acid

[0103] Caprylic acid

[0104] The ethanol containing process stream is subjected to step (c)(i) as depicted in FIG. 1. Here, the ethanol containing process stream, containing the aromatic compounds, is separated into an ethanol containing fraction and a remaining process stream where the aromatic compounds are accumulated. The distribution of aromatic compounds is depicted in FIG. 7. The aromatic compound “acetaldehyde”, which is considered being an off flavor, is adsorbed on the adsorber and hence accumulates in the ethanol containing fraction. (FIG. 8)

[0105] The experiment was conducted the following way:

[0106] 1 L of the ethanol containing process stream was placed in a tempered (15° C.) container and conveyed by using a peristaltic pump (Watson Marlow, 520DU) into the stripping column (diameter 60 mm, height 1400 mm) at the top of the column with a volume flow of 2 L/h. The stripping column was filled with filling material (Teflon raschig rings, diameter 6 mm, height 6 mm, Sigma-Aldrich, Z243477). A counter-currently flowing inert gas stream (N2, 12 L/min) was conveyed from the bottom to the top of the stripping column. The stripping column was used at a pressure of 1.013 bar and a temperature of 22° C. The inert gas stream was contacted with the adsorber columns and recycled into the stripping column. For adsorption three adsorber columns were used, filled with adsorber material (Clariant, TZP9028; MFI Zeolith, molar SiO2/Al2O3 ratio 1000). Simultaneously two columns were used for adsorption, one column for desorption. For desorption of the ethanol from the adsorber columns an inert gas stream (N2, 0.6 L/min) was used. By a vacuum pump the pressure in the adsorber columns was reduced to 100 mbar. After a cycle time of 20 min the columns changed their role. 72 cycles were conducted.

[0107] Example 3 shows, that the inventive process, selectively separates ethanol from the ethanol containing process stream but retains the aromatic compounds within the remaining process stream. FIGS. 6 and 7 show that a major part of the aromatic compounds separated from the beverage by state of the art de-alcoholization processes can be recycled to the final product. In addition, the off-flavor acetaldehyde can be significantly reduced (FIG. 8).

EXAMPLE 4: DETERMINATION OF RECYCLABLE REMAINING PROCESS STREAM, IN COMPARISON TO RECYCLING OF ETHANOL CONTAINING PROCESS STREAM

[0108] In Example 4, the amount of recyclable remaining process stream will be determined. Finally it will also be compare to a direct recycling of the ethanol containing process stream. The recyclable remaining process stream is determined by its ethanol concentration. The smaller the ethanol concentration in the ethanol containing process stream, the more can be recycled into the beverage. Two parameters are decisive for the ethanol concentration in the remaining process stream. The ethanol concentration of the educt of the inventive method (the ethanol containing process stream) and the temperature at which the method is conducted.

[0109] In this example, 4 experiments were performed varying these parameters. The experiments were conducted as described in the experiment description in Example 3. Table 2, columns 2 and 3 show the parameters. The ethanol concentration of the educt was varied between 5.-% and 40.-% and the temperature was varied between 5° C. and 20° C. This way, 4 remaining process streams were produced. Table 2 shows in column 4, the ethanol concentration for these remaining process streams. Furthermore, in column 5, the amounts of remaining process stream recycled to 1 L de-alcoholized beverage are calculated. This calculation takes as a basis, that the de-alcoholized beverage has an ethanol concentration of 0.01 vol.-% and can be topped up with remaining process stream to 0.5 vol.-%.

[0110] Table 2 shows the parameters applied in the experiments, the remaining ethanol concentration in the remaining process stream and the amount of remaining process stream that can be recycled to 1 L of de-alcoholized beverage.

TABLE-US-00002 Amount of Ethanol remaining concentration Ethanol process stream in ethanol Temperature concentration recycled to 1 L containing of inventive in remaining de-alcoholized process stream method process stream beverage Sample [vol.-%] [° C.] [vol.-%] [ml] 1 5 5 2.3 272 2 5 20 0.4 ∞ (372) * 3 40 5 10.2  51 4 40 20 3.2 181 * As the ethanol concentration of the second sample is below 0.5% vol the generated volume of remaining process stream can be added completely. In a standard thermal dealcoholization process, 389 ml of ethanol containing process stream are produced during the production of 1 L of dealcoholized beverage. From 389 ml of ethanol containing process stream, 372 ml of remaining process stream can be generated by the inventive method.

[0111] To compare the values to the state of the art, table 3 shows a list of the amount of ethanol containing process stream, recycled directly into a de-alcoholized beverage. Here again the amount of recycled product differs with the ethanol concentration. Also here, the calculation takes as a basis, that the de-alcoholized beverage has an ethanol concentration of 0.01 vol.-% and can be topped up with ethanol containing process stream to 0.5 vol.-%.

[0112] Table 3 shows recyclable amounts of ethanol containing process stream for different ethanol concentrations when directly recycled into the de-alcoholized beverage.

TABLE-US-00003 Amount of ethanol Ethanol concentration containing process in ethanol containing stream recycled to process stream de-alcoholized beverage Sample [vol.-%] [ml] A 5 109 B 40 12

[0113] The larger the amount of recycled process stream (ethanol containing process stream or remaining process stream), the more aromatic compounds can be re-transferred to the final beverage product. Comparing sample A to sample 1 and 2, and sample B to samples 3 and 4, it gets clear that by implementing the method of invention, the amount of recycled process stream transferred to 1 L de-alcoholized beverage is significantly larger than the amount, which could have been recycled without the inventive treatment. For an ethanol concentration of 5 vol. %, 109 ml of an ethanol containing process stream (sample A) could be recycled, in case the inventive method is applied, a remaining process stream of 272 ml (sample 1) or even 372 ml (sample 2) can be recycled into the dealcoholized beverage. This means doubling or even tripling the recyclable amount. Therefore, a much higher content of aromatic compounds can be recycled into the dealcoholized beverage. For an ethanol containing process stream with an ethanol concentration of 40 vol.-%, the increase is even more significant. Instead of recycling 12 ml back to the dealcoholized beverage (sample B), 51 ml (sample 3) or even 181 ml (sample 4) of remaining process stream can be recycled. This means the recycled amount is 5 or even 15 times higher.

EXAMPLE 5: QUALITY AND QUANTITY OF RE-TRANSFERABLE AROMATIC COMPOUNDS

[0114] In Example 4, the possible volumes of recyclable remaining process stream were already calculated and compared to a direct recycling of ethanol containing process stream. In this example the quality and quantity of the aromatic compounds were determined for the volumes calculated. Here again, sample A is compared to samples 1 and 2 and sample B is compared to samples 3 and 4. The aromatic compounds were analyzed by mass spectrometry. The following aromatic compounds were analyzed.

[0115] Acetic acid isobutyl ester

[0116] Ethyl butyrate

[0117] Ethylhexanoat

[0118] Isovaleric acid

[0119] Hexanoic acid

[0120] Octanoic acid

[0121] FIG. 9 shows the amounts of aromatic compounds, that can be re-added to the de-alcoholized beverage by recycling the volume of sample A, sample 1 or sample 2.

[0122] FIG. 10 shows the amounts of aromatic compounds, that can be re-added to the de-alcoholized beverage by recycling the volume of sample B, sample 3 or sample 4.

[0123] One can see in both figures, that the recycling of remaining process streams instead of ethanol containing process streams results in significantly higher amounts of core aromatic compounds in the final beverage product for exemplary potential production temperatures of 5 and 20° C. Comparing for example the amounts of aromatic compounds in sample B the ones in sample 4, the increase can be shown very intensely.

[0124] The amount of acetic acid isobutyl ester recycled into the final beverage product can be increased by factor 14 by applying the method of invention. The amount of ethyl butyrate can be increased by factor 4. The amount of ethylhexanoat by factor 3 and the amounts of isovaleric acid, hexanoic acid and octanoic acid even by the factors 35, 55 and 28.