EP0519024A1

EP0519024A1 - Dealcoholizing method

Info

Publication number: EP0519024A1
Application number: EP92900211A
Authority: EP
Inventors: Jean-Marc Girard; Albert Duriaux; Philippe Cuenat; Michel Jaccard
Original assignee: Migros Genossenschafts Bund
Current assignee: Migros Genossenschafts Bund
Priority date: 1991-01-07
Filing date: 1991-12-13
Publication date: 1992-12-23
Also published as: CA2077639A1; US5324435A; TNSN91126A1; OA09798A; AR246557A1; MA22366A1; WO1992012232A1; FR2671355B1; JO1693B1; ZA919924B; FR2671355A1; JPH06500236A

Abstract

Procédé dans lequel on effectue le stockage et le traitement du liquide à désalcooliser dans un circuit de désalcoolisation sous une atmosphère non oxydante, on procède à une diafiltration partielle de ce liquide non dilué dans un module d'osmose inverse, on procède à un échange d'eau en compensant partiellement la perte de volume due à la séparation du perméat par un apport d'eau déminéralisée totalement débarrassée de toute trace de chlore et desaérée et on rajoute au rétentat des ingrédients naturels ou synthétiques non extraits du liquide original par traitement thermique. Afin d'obtenir une désalcoolisation complète, on procède à une préconcentration à une température comprise entre 10 et 15 °C du liquide initial à désalcooliser et, au cours du traitement, on procède de façon alternée à au moins une concentration, une diafiltration et une dilution. Ce procédé est notamment utilisé pour traiter le vin, la bière et le cidre et leur permet de garder leurs normes de qualités et de goût requises.Process in which the storage and processing of the liquid to be dealcoholized is carried out in a dealcoholization circuit under a non-oxidizing atmosphere, a partial diafiltration of this undiluted liquid is carried out in a reverse osmosis module, an exchange of water by partially compensating for the loss of volume due to the separation of the permeate by a supply of demineralized water completely free of all traces of chlorine and deaerated and natural or synthetic ingredients are not added to the retentate that are not extracted from the original liquid by heat treatment. In order to obtain complete dealcoholization, the initial liquid to be dealcoholized is preconcentrated at a temperature of between 10 and 15 ° C. and, during treatment, at least one concentration, one diafiltration and one dilution. This process is used in particular to treat wine, beer and cider and allows them to maintain their required standards of quality and taste.

Description

DECOOLING PROCESS

The present invention relates to a dealcoholization process by reverse osmosis of an alcoholic liquid, in particular wine, beer or cider, in which the storage and treatment of this liquid to be dealcoholized is carried out in a dealcoholization circuit under a non-alcoholic atmosphere. oxidant, in which a partial diafiltration of this liquid is carried out in a reverse osmosis module, in which a water exchange is carried out by partially compensating for the loss of volume due to the separation of the permeate by a supply of water demineralized, completely free of all traces of chlorine and deaerated if necessary, and in which natural or synthetic ingredients are added to the retentate that are not extracted from the original liquid by heat treatment.

A process of this type is already known, described in the international patent application published under No. ² WO 87/03902. This process has proved to be quite remarkable and has led to extremely interesting results, in particular for the production of fully or partially dealcoholized wine whose residual alcohol level is of the order of 0.5 to 2%. Total dealcoholization has proven problematic because of the excessively long duration of treatment, which has the effect of making the process expensive and therefore unprofitable.

The process described in the French patent application published under N ⁹ 2 620 129 also relates to a process for dealcoholizing liquids by reverse osmosis. In this process, before the diafiltration, the initial liquid is diluted by adding an equivalent quantity of water. This water is then removed by a strong reconcentration carried out at a relatively high temperature (25 to 35 ° C). The introduction of this water has various drawbacks. On the one hand, if this reconcentration is carried out at low temperature, the total duration of dealcoholization is greatly increased, hence the need to work at high temperature in an attempt to reduce this duration. On the other hand, in terms of taste, the reconcentration at a relatively high temperature so as not to lengthen the operation too much leads to a loss of "vinous" elements such as organic acids, flavors and salts, and therefore causes a reduction in the quality of the product obtained. In addition, the fact that the concentration factor is greater than 5 strongly distorts the undiluted wine as a result of chemical phenomena such as tartaric precipitation or protein instability in the case of white wine. Finally, the final dilution of the dealcoholized liquid obtained by this process significantly alters its quality.

The present invention proposes to provide a solution to these problems by making it possible to carry out complete dealcoholization with good yield and leading to an undiluted product which meets the standards of quality and taste required in the matter.

For this purpose, the method according to the invention is characterized in that one proceeds to a preconcentration of the initial liquid to be dealcoholized undiluted, and in that during the treatment one proceeds alternately to at least one concentration at low temperature, diafiltration also at low temperature and dilution.

Advantageously, the concentration and the diafiltration are carried out at a temperature between 10 and 15 ° C.

Preferably, the pH can be stabilized during the treatment.

According to a preferred embodiment, the preconcentration rate of the liquid to be dealcoholized is less than 5 and preferably between 3 and 4.

Advantageously, the ratio R = Dd / Di is maintained, in which Dd represents the flow rate of the permeate at the start of the diafiltration and Di the initial flow rate of the permeate at the start of the dealcoholization, between 60 and 80% and preferably higher at 65%. Also according to this embodiment, the initial flow of permeate Di, at the start of the dealcoholization, is at least between 10 and 15 1 / h / m ² of filtering surface, and preferably between 12, 6-13 1 / h / m ² for white wines and between 11.6-12 1 / h / m ² for red wines.

According to a preferred embodiment of the process, the pH is stabilized by means of tartaric acid and / or tartrates if it is desired to fall below 0.5% by volume of alcohol.

According to another embodiment of this method, a primary diafiltration is carried out successively, a concentration, the main diafiltration and a dilution to the final volume chosen.

Preferably, the primary dialfitration is carried out until a volume of permeate of between 0.5 and 2% of the wine initially used is obtained.

According to a particularly advantageous embodiment, one proceeds successively to a concentration, a diafiltration, a partial dilution, a reconcentration, a diafiltration and a dilution to the final volume chosen.

In these embodiments, the different processing phases, or combinations of these phases, are repeated at least twice.

Advantageously, procedures are carried out regularly before treatment and / or during treatment for rinsing-fouling of the membranes.

Preferably, these interventions are carried out by means of aqueous rinsing-fouling solutions. An aqueous solution for rinsing and soiling may contain caustic soda, nitric acid or hydrogen peroxide, as well as enzymatic preparations. The entire installation is also rinsed before the start of dealcoholization, using an aqueous solution containing fine alcohol and preferably about 11% by volume of alcohol.

In the embodiments described, a partial or total diafiltration is carried out before the treatment and an acidification is carried out during the dealcoholization treatment and a concentration of the dealcoholized retentate previously deacidified is carried out in order to preserve it.

When reconstituting the dealcoholized wine, ingredients are preferably introduced whose volume is over-concentrated with respect to the initial volume of wine. Food acids can also be introduced.

Advantageously, these food acids can comprise lactic acid or tartaric acid and Na-hydrogen tartrate.

It is also possible to introduce into the alcohol-free wine substances chosen from the following group of substances: glycerin, NaCl, succinic acid, citric acid, malic acid, glucose, NaHCU3, K2CO3, fructose and grape juice.

Advantageously, the acidity is readjusted by means of tartaric acid after control of this acidity, the other ingredients having been added beforehand.

In the context of this process, numerous tests have been carried out with membranes of the HC 50 type and with a module of 19 m ² . It has been found that a preconcentration of the undiluted treated wine, by a factor of between 2 and 5 and preferably between 3 and 4-, before diafiltration has the advantage of reducing the treatment time by around 35% and d '' about four times the amount of permeate produced. By way of example, the partial dealcoholization of 1028 liters and 2217 liters of wine respectively was carried out according to a technique A which does not provide for preconcentration and a technique B corresponding to the process described above. The results are shown in the table below.

The time saving in case B is 35%. The gain of R is four times.

These results proved to be correct only on condition that the initial flow of the membranes, at the time of start-up, does not drop below 12.6 1 / h / m ² , i.e. a 240 1 / h flow rate for 19 m ² of membrane surface, and provided that the concentration rate, before diafiltration, does not cause the permeate flow to drop below 65-70%, and more specific 70% of its initial value at the time of start-up. In other words,

Dd i 65-70% Di where:

Dd represents the flow rate of the permeate at the start of the diafiltration, and Di represents the initial flow rate of the permeate at start-up. In addition, a preconcentration of undiluted wine before diafiltration, by a factor greater than 3-4 times, has the effect of denaturing the dealcoholized wine and is not indicated from an organic point of view.

A test was carried out on 10,560 liters of white wine which were concentrated 7.5 times before diafiltration. The retentate obtained is brown, cloudy. After reconstitution, the dealcoholized wine obtained had an old taste that wine obtained from a 3-fold concentrate did not have at all. The results obtained with composite membranes with a surface area of 19 m ² , from white wine, are shown below.

We deduce that:

1.- the preconcentration of undiluted wine must not exceed 2 to 5 times and preferably 3 to 4 times due to organoleptic depreciations; 2.- the ratio R = Dd / Di must remain between 60 and 80% and preferably greater than 65-70% due to a decrease in performance;

3.- the initial permeate flow at the start of the dealcoholization on the undiluted wine must be at least between 10 and 15 1 / h / m ² and preferably 12.6-13 1 / h / m ² for the wines whites and 11.6-12 1 / h / m ² for reds.

There has also been a noticeable gain in time when the different phases of treatment are alternated during the dealcoholization operation. To this end, we proceeded as follows:

a .- During a first test, a primary diafiltration of the undiluted wine was carried out until a volume of permeate of between 0.5 and 2% of the wine initially used was obtained, followed by '' a concentration then a main diafiltration followed by a dilution.

b. - During a second test, a concentration was carried out followed by a diafiltration, a partial dilution, a reconcentration, a diafiltration and finally a dilution.

Other combinations are possible and the above-mentioned phases can be repeated several times.

Finally, to guarantee an optimal dealcoholization yield, that is to say to reduce the duration of the operation to a minimum and avoid imparting unpleasant tastes to the dealcoholized wine, it has been necessary to develop cleaning processes combining a certain number of specific interventions using a set of chemicals intended to ensure sufficient cleaning of the membranes, in particular after a dealcoholization phase of red wine. To guarantee an initial permeate flow of around 11.6 1 / h / m ² for red wines and around 12.6 1 / h / m ² for white wines, a combination of chemical treatments intended to restore sufficient permeability to the membranes to ensure the desired flow rate.

Firstly, a rinse with nitric acid is carried out. For 115 liters of water from the installation, 624 ml of HNO3, 65%, are added to a treatment tank and this mixture is circulated brought to a pressure of the order of 10 to 12 bars, for a minimum of thirty minutes. Then rinse with running water for at least fifteen minutes. After this rinsing with water, a solution of hydrogen peroxide is prepared by adding 160 ml of 35% hydrogen peroxide to 115 liters of water from the installation and a circulation of this mixture is brought to pressure. from 10 to 12 bars, for thirty minutes. Then rinse with water as before. During the dealcoholization process, as soon as the permeate flow tends to drop below 60 to 80% or preferably below 65 to 70% of its value when it is started up, a intermediate treatment of membranes consisting of:

1.- for white wines, to clean the membranes using a solution containing 40 liters of hot water at 30 ° C, 810 g of "Ultrasil 53" sold by the company Henkel and 50 g of caustic soda at 100 % in powder.

2.- for red wines, rinse with nitric acid followed by rinsing with hydrogen peroxide as mentioned above.

Between each dealcoholization operation of 20,000 liters of white or red wine, an appropriate cleaning of the membranes is carried out. The parameters of these interventions are summarized in the table below: Product Dosage Pressure / Bar Duration of treatment Temperature "C of treatment (for 1151t / (module inlet) (minutes) (maximum) 55 tub, 60 Inst.) (Heat water with steam hose if necessary)

Rinsing (city water) 10-12 15 Ultrasil 15 1, 000 kg 10-12 5 -10 40 Rinsing (city water) 10-12 15 Ultrasil 55 0.575 kg 10-12 10 leave 12 hours 30-35 Rinsing (city water) 10-12 15 Ultrasil 75 0.345 kg 10-12 20 40 Rinsing (city water) 10-12 15 Ultrasil 15 0.750 kg 10-12 30-40 40 Rinsing (city water) 10-12 15

By proceeding in this way, it was possible to preserve intact the initial capacity for performance of a module operating for approximately six years in an uninterrupted manner.

To avoid communicating dubious tastes to the dealcoholized wine, such as stagnant, cork and musty tastes, before each dealcoholization, the module and the piping are rinsed with an aqueous solution containing about 11% by volume of fine alcohol consisting for example of 94% ethanol and 2% by volume of propyl alcohol. The rinsing alcohol is recirculated in the module and piping circuit for at least 15 minutes before being expelled by the wine to be dealcoholized. No rinsing with water, which could reintroduce questionable tastes, is carried out between this rinsing with alcohol and the start of the dealcoholization process.

On the other hand, to avoid oxidation and old tastes in dealcoholized wines, it has proved advantageous to deaerate the demineralized water introduced in the process beforehand, until its oxygen content is reduced to less than 0.1 mg / 1.

In addition, to transport and store the retentate, it may be useful to concentrate it. For this purpose, in order to prevent the product from becoming cloudy as soon as precipitates are formed, it is advantageous to carry out a partial or total deacidification of the wine to be dealcoholized before concentration and dealcoholization.

Tests were carried out on red Algerian wine having a content of 10.8% by volume of alcohol and a total titratable acidity content of 5.56 g / 1, a pH of 3.25 and a tartaric acidity. 2.5 g / 1. Deacidification was carried out according to the usual cellar techniques to bring it to a content of 3.10 g / l of total acidity, a pH of 4.10 and a tartaric acidity of 0.8 g / l. This deacidified wine was normally dealcoholized and concentrated 3, 5 times. The retentate was stored for two and a half months at 10 ° C. without any clouding or formation of precipitate being observed. He was then reconstructed. For this purpose, we took a part of concentrated retentate to which we added two parts of water as well as the usual ingredients while also compensating for the acidity lost during the deacidification process. A comparative tasting revealed that a non-deacidified witness before dealcoholization and immediate reconstitution after dealcoholization had strictly the same taste as the previously deacidified sample.

To ensure the preparation of dealcoholized wine having an alcohol content of less than 0.5% by volume, the same techniques are used as those set out above, however introducing two additional characteristics which are as follows:

α / an acidification of the retentate is carried out during dealcoholization. It has been found that during dealcoholization to a content of less than 0.5% of the alcohol content, the loss of acidity for wine, with the membranes of the HC50 type used, can be large enough to cause an increase. the pH of the wine leading to a significant change in its qualities, in particular its color, its physical and bacteriological stability, etc. To avoid these phenomena, acidity, for example in the form of tartaric acid, tartrates or other food acids, is periodically reinjected into the wine to be dealcoholized, during the dealcoholization treatment, to stabilize the pH. By way of example, 15,130 kg of red wine originating from Algeria were treated and containing, for example 11.4% by volume of alcohol. The dealcoholization process made it possible to bring the volume of alcohol down to 3.8% by preconcentrating the undiluted wine by a rate equal to 2. From the moment this volume of alcohol is reached, it was added 2.0 g of tartaric acid per liter of concentrated retentate circulated in the circuit. From this moment, the concentration is increased during dealcoholization until reaching a rate equal to 5 without causing a visible change in the acidity of the wine. Diafiltration and dilution were then carried out according to the process mentioned above, and dealcoholized red wine was obtained. having a final alcohol content of less than 0.03% by volume, the control having been carried out by enzymatic analysis.

β / A modification of the dealcoholization process is carried out when the alcohol content drops below 0.5% by volume of alcohol. When the volume of alcohol drops below 1%, it has been found that it is advantageous to alternate the concentration, dilution and diafiltration phases to complete the dealcoholization. For dealcoholized wines at a higher rate, the dealcoholization process is advantageously terminated by dilution after diafiltration.

By way of example, 846 1 of red Algerian wine having a content of 12.2% by volume of alcohol was treated to bring this volume of alcohol to 0.02%. The durations of the phases of this treatment are recorded in the table below:

It is found that by proceeding only to the first three phases up to a final alcohol level of 0.02%, it took 23.5 hours or 27.8 hours per 1000 liters. Consequently, the time saving observed is of the order of 37%.

Other combinations of concentration, diafiltration and dilution phases can be envisaged.

With regard to the reconstitution of the wine and in particular of the taste of this wine after the dealcoholization operation, in other words in order to improve the organoleptic quality of the dealcoholized wine and give it a less aqueous taste, it is advantageous to increase somewhat the quantity of the ingredients compared to the initial volume of wine treated.

Instead of rediluting the retentate at the end of deacoolization at the initial rate of the treated wine, a defined percentage of volume is deduced from this initial rate which will not be found in the final wine. This percentage is for example equal to the value of the volume occupied by the alcohol in the wine to be dealcoholized. The ingredients that are added to the retentate have a volume proportional to the initial volume of the treated wine, or possibly greater than this volume and no longer proportional to the volume of retentate. As a result, dealcoholized wine will have a more accentuated content of vinous elements.

For example, if 10,000 liters of dealcoholized wine containing 11% alcohol are treated, the volume of alcohol contained in this wine being 1,100 liters, the volume of dealcoholized wine obtained is 8 900 liters. In the prior art, these 8,900 liters were reduced to 10,000 liters by adding water and the ingredients were calculated on a basis of 10,000 liters. In the process described above, the retentate is not rediluted and an amount of ingredients calculated on the basis of 10,000 liters is added to the 8,900 liters of dealcoholized wine obtained. It is understood that the dose of ingredients could be increased so as to make it proportional to a volume greater than that of the initial wine to be dealcoholized. Nevertheless, experience shows that the additional addition of ingredients corresponding to the volume of alcohol contained in the initial volume of wine is enough to remove the watery taste due to loss of alcohol.

As mentioned previously, during the dealcoholization operation, part of the acidity must be compensated, in particular to restore body to the dealcoholized wine. During the reconstitution at the end of dealcoholization, food acids can be added to the retentate.

As an example, lactic acid can be used at a rate of

0.65 g / 1 calculated on the initial volume of wine for red wines and of the order of 2.6 g / 1 calculated on the initial volume with regard to rosé wines and white wines.

It is also possible to add tartaric acid and Na-hydrogen-tartrate in an amount sufficient to reach a titratable total acidity rate, which is for example of the order of 7.4 g / l in the desalted wine. . To do this, the retentate reduced to the volume calculated above is mixed in the reconstitution tank, grape juice concentrate in an amount approximately equal to 49.7 g / 1 of initial wine, fructose in an amount approximately equal to 26 , 5 g / l of initial wine, lactic acid as indicated above and sodium hydrogen tartrate in the amount mentioned above.

This entire tank is then stirred for a period of approximately

1/4 hour to 1/2 hour so that the mixture is homogeneous. A sample is then taken for a titer verification.

The difference in acidity between the titer measured and the desired titer is completed in the form of tartaric acid. For example, 83 kg of tartaric acid were added to increase the amount of acidity of 11,630 liters of dealcoholized wine from 5.6 g / l to 7.5 g / l.

Other tartrate salts have been used but experience has shown that K-Hydrogen-tartrate is unsuitable because of its insol- lubricity in wine and that K-Na tartrate gives the wine a soapy and pharmaceutical taste beyond an amount of 80 mg / 1.

It is noted that the sodium level in the dealcoholized wine thus re¬ constituted, even after the addition of Na-Hydrogen-tartrate, is not significantly increased compared to the initial wine.

During the reconstitution, other ingredients can be added to obtain special effects. These ingredients as well as the rates

10 maximums not to be exceeded for organoleptic reasons are given in the table below:

i -3

20

25

30

One of the possible uses of the alcohol from the process is vinegar. In this industry, alcohol diluted to 10 or 12% by volume is used. During the dealcoholization process, it is possible to envisage directly collecting a fraction of permeate, one of which

35 alcohol volume content is between 7 and 8% and increase by concentration this alcohol volume to 10 to 15%. The cost of the operation is relatively modest since it allows the use of inexpensive equipment.

Claims

1. Process for dealcoholization by reverse osmosis of an alcoholic liquid, in particular wine, beer or cider, in which the storage and treatment of this liquid to be dealcoholized is carried out in a dealcoholization circuit under a non-oxidizing atmosphere, in in which a partial diafiltration of this liquid is carried out in a reverse osmosis module, in which an exchange of water is carried out by partially compensating the loss of volume due to the separation of the permeate by a supply of completely freed demineralized water of any trace of chlorine and deaerated if necessary, and in which natural or synthetic ingredients not extracted from the original liquid by heat treatment are added to the retentate, characterized in that a preconcentration of the initial liquid to be dealcoholized undiluted is carried out, and in that during the treatment at least one concentration is carried out alternately at low temperature, a diafiltration also at low temperature and a dilution.

2. Method according to claim 1, characterized in that the concentration is carried out at a temperature between 10 and 15 °C.

3. Method according to claim 1, characterized in that the pH is stabilized during the treatment.

4. Method according to claim 1, characterized in that the preconcentration rate of the liquid to be dealcoholized is less than 5 and preferably between 3 and 4.

5. Method according to claim 1, characterized in that the ratio R = Dd / Di is maintained, in which Dd represents the flow rate of the permeate at the start of the diafiltration, and Di the initial flow rate of the permeate, between 60 and 80% and preferably greater than 65%.

6. Method according to claim 1, characterized in that the initial flow of permeate Di, at the start of the dealcoholization, is at least between 10 and 15 1/h/m ² of filtering surface, and preferably between 12.6-13 1/h/m ² for white wines and between 11.6-12 1/h/m ² for wines red.

1. Method according to claim 3, characterized in that the pH is stabilized by means of tartaric acid and/or tartrates.

8. Method according to claim 1, characterized in that one proceeds successively to a primary diafiltration, to a concentration, to the main diafiltration and to a dilution until the chosen final volume.

9. Method according to claim 8, characterized in that the primary dialfitration is carried out until a volume of permeate of between 0.5 and 2% of the wine initially used is obtained.

10. Method according to claim 1, characterized in that one successively carries out a concentration, a diafiltration, a partial dilution, a reconcentration, a diafiltration and a dilution until the chosen final volume.

11. Method according to any one of claims 8 or 10, characterized in that the different treatment phases, or combinations of these phases, are repeated at least twice.

12. Method according to claim 1, characterized in that rinsing-defouling of the membranes is carried out regularly before treatment and/or during treatment.

13. Method according to claim 12, characterized in that these interventions are carried out using aqueous solutions.

14. Method according to claim 13, characterized in that the aqueous rinsing-defouling solution contains caustic soda.

15. Method according to claim 13, characterized in that the aqueous rinsing-defouling solution contains nitric acid.

16. Method according to claim 13, characterized in that the aqueous rinsing-defouling solution contains hydrogen peroxide.

17. Method according to claim 1, characterized in that the entire installation is rinsed before the start of dealcoholization, using an aqueous solution containing fine alcohol.

18. Method according to claim 17, characterized in that the rinsing solution contains approximately 11% by volume of alcohol.

19- Method according to claim 1, characterized in that you carry out a partial or total diafiltration before the treatment and an acidification during the dealcoholization treatment.

20. Method according to claim 19, characterized in that we carry out a concentration of the dealcoholized retentate previously deacidified to preserve it.

21. Method according to claim 1, characterized in that during the reconstitution of the dealcoholized wine, ingredients are introduced whose volume is in overconcentration compared to the initial volume of wine.

22. Method according to claim 1, characterized in that during the reconstitution of the dealcoholized wine, food acids are introduced.

23. Method according to claim 22, characterized in that these food acids comprise lactic acid.

24. Method according to claim 22, characterized in that these food acids comprise a mixture of tartaric acid and Na-Hydrogen tartrate.

25- Method according to claim 1, characterized in that substances chosen from the following group of substances are introduced into the dealcoholized wine; glycerin, NaCl, succinic acid, citric acid, malic acid, glucose, NaHCθ3, K2CO3, fructose and grape juice.

26. Method according to claim 1, characterized in that the acidity is readjusted using tartaric acid after controlling this acidity, the other ingredients having been previously added.