Method for producing concentrated grape juice and method for producing wine

Abstract

To provide a method for producing a concentrated grape juice which has a required sugar content and in which aroma and flavor are retained, and a method for producing wine using the concentrated grape juice.SOLUTION: A method for producing a concentrated grape juice according to the present disclosure includes a solid-content recovery step of recovering solid contents in grape juice under an inert-gas atmosphere, and a forward-osmosis-membrane concentration step of concentrating the grape juice from which the solid contents have been recovered, by passing it through a forward osmosis membrane under an inert-gas atmosphere.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for producing concentrated grape must and a method for producing wine. [Background technology]

[0002] Grapes grown in Japan for the purpose of winemaking are cultivated in a climate with high temperatures and humidity and little difference in temperature between day and night, which is a harsh environment for the satisfactory development and aging of wine, and sometimes immature grapes with low sugar content are harvested.

[0003] Therefore, when yeast fermentation is performed on grape juice with a low sugar content, sugar content is traditionally increased by adding sugar (chaptalization). Furthermore, fermentation aids containing nutrients and organic acids are added as needed to supplement the activity of the yeast. Chaptaration is a necessary technique for brewing wine from grape juice with a low sugar content. However, the wine obtained from grape juice that has been chaptarized has the problem of being low in flavor and taste.

[0004] For these reasons, concentrating grape juice has been adopted as a method for increasing sugar content without chaptalization. Conventional concentration techniques used in winemaking include vacuum concentration and reverse osmosis membrane concentration. The vacuum concentration method requires heating under reduced pressure, which reduces organic acids and nutrients, and also reduces flavor.

[0005] On the other hand, the reverse osmosis membrane concentration method significantly improves the problem of the reduction of organic acids and nutrients, but the problem of the deterioration of flavor due to the need for pressurization remains.Furthermore, the reverse osmosis membrane concentration method has problems such as the high cost and volume of the required equipment and the complicated operation.

[0006] As an example of using a reverse osmosis membrane concentration method, for example, Patent Document 1 discloses concentrating a coffee extract using a reverse osmosis membrane. However, this method requires a step of recovering the aroma components from the concentrated and recovered liquid by evaporation under reduced pressure, since aroma components are contained in the concentrated and recovered water.

[0007] Due to the above background, in France, under the Appellation d'Origine Contrôlée (AOC) system, vacuum concentration and reverse osmosis concentration methods are only permitted in winemaking under certain conditions. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-319749 Summary of the Invention [Problem to be solved by the invention]

[0009] As winemaking technology advances, there is a demand for concentrated grape must that has a required sugar content and retains its flavor, and for wine obtained from the concentrated grape must.

[0010] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a method for producing concentrated grape juice that has a required sugar content and retains its flavor, and a method for producing wine using the concentrated grape juice. [Means for solving the problem]

[0011] That is, the present invention includes the following aspects. [1] A method for producing concentrated grape juice, comprising: a solids recovery step of recovering solids from the grape juice under an inert gas atmosphere; and a forward osmosis membrane concentration step of concentrating the grape juice from which the solids have been recovered by passing it through a forward osmosis membrane under an inert gas atmosphere. [2] The method for producing concentrated grape juice according to [1], wherein the forward osmosis membrane concentration step uses a hollow fiber membrane module in which hollow fiber forward osmosis membranes are modularized. [3] The method for producing concentrated grape juice according to [1] or [2], wherein the solids recovery step includes a filtration step of filtering the grape juice. [4] The method for producing concentrated grape juice according to [3], wherein the grape juice is filtered using a cross-flow method in the filtration step. [5] The method for producing concentrated grape must according to any one of [1] to [4], wherein the inert gas is nitrogen, argon, carbon dioxide, or a mixture thereof. [6] The method for producing concentrated grape must according to any one of [1] to [5], wherein the solid content includes a sediment component. [7] The method for producing concentrated grape juice according to any one of [1] to [6], wherein the sugar content of the concentrated grape juice is 18.5 to 24.0. [8] A method for producing wine, which comprises yeast fermentation using concentrated grape must obtained by the production method according to any one of [1] to [7]. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a method for producing concentrated grape juice having a required sugar content and retaining flavor and aroma, and a method for producing wine using the concentrated grape juice. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram showing an example of a production apparatus used in the method for producing concentrated grape juice and wine according to this embodiment. [Figure 2] FIG. 2 is a schematic diagram showing an example of a production apparatus used in the method for producing concentrated grape juice and wine according to this embodiment. [Figure 3] FIG. 3 is a schematic diagram showing an example of a cross-flow filtration device in a production apparatus used in the method for producing concentrated grape juice and wine according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] In this specification, the term "comprise" is a concept that encompasses all of "comprise," "consist essentially of," and "consist only of."

[0015] <Method for producing concentrated grape juice> The method for producing concentrated grape juice according to this embodiment includes a solids recovery step of recovering solids from the grape juice under an inert gas atmosphere, and a forward osmosis membrane concentration step of concentrating the grape juice from which the solids have been recovered by passing it through a forward osmosis membrane under an inert gas atmosphere.

[0016] <Grape juice> The grape juice in this embodiment is not particularly limited as long as it is obtained from grapes used in winemaking. The grape juice can be extracted using a known method, such as pressing with a press.

[0017] <Solid content recovery process> In the solid content recovery step, solid content in the grape juice is recovered under an inert gas atmosphere.

[0018] The method for producing concentrated grape juice according to this embodiment can prevent oxidation of the grape juice by recovering solids from the grape juice under an inert gas atmosphere, and can also concentrate the grape juice without clogging the forward osmosis membrane in the forward osmosis membrane concentration step described below.

[0019] The solid content recovered in the solid content recovery step includes sediment components (organic acids, etc.). In this specification, the term "seed component" is a general term for solid components including organic acids and the like.

[0020] The solid content recovery step may include either or both of a solid content precipitation step in which the grape juice is allowed to stand to precipitate solids in the grape juice, and a filtration step in which the grape juice is filtered. However, from the viewpoint of more easily avoiding clogging of the forward osmosis membrane in the forward osmosis membrane concentration step described below, it is preferable to include the filtration step, and it is more preferable to perform the filtration step after the solid content precipitation step.

[0021] The standing time in the solids settling step is not particularly limited, but is usually 12 to 24 hours. This operation of leaving the grape must in a tank and allowing impurities to settle to the bottom of the tank before fermenting the grape must is usually called "clarification (debourbage)."

[0022] The filtration method in the filtration step may be a dead-end method or a cross-flow method, of which cross-flow filtration is preferred from the viewpoint of further improving the quality of the concentrated grape must and concentrated wine.

[0023] The mesh size of the filter used in the filtration step is not particularly limited, but from the viewpoint of preventing clogging of the forward osmosis membrane in the forward osmosis membrane concentration step described below, a filter with mesh size that allows for the recovery of tartar and sediment components in the grape juice is preferred. A preliminary experiment may be conducted using the grape juice to be treated to select a filter with mesh size that allows for the appropriate recovery of tartar and sediment components. From the viewpoint of facilitating long-term continuous operation, the filter used in the filtration step preferably has a large filtration area, and it is more preferable to use multiple filters in parallel. Using multiple filters in parallel makes it possible to avoid interruptions to the filtration step due to filter replacement.

[0024] In the case of cross-flow filtration, a multi-stage configuration using multiple filters with different mesh sizes is preferred in order to accommodate tartar and sediment components of various sizes. Specifically, when using two types of filters with different mesh sizes, it is more preferred to use the filter with the larger mesh size as the front filter, and to filter the grape juice filtered through the front filter with a rear filter with smaller mesh sizes than the front filter.

[0025] The oxygen concentration in the inert gas atmosphere in the solid content recovery step is not particularly limited as long as the components in the grape must are not oxidized, but is preferably 5.0% by volume or less, more preferably 1.0% by volume or less, and even more preferably 0.1% by volume or less.

[0026] As the inert gas used in the solid content recovery step, nitrogen, argon, carbon dioxide, and mixed gases thereof are preferred, from the viewpoint of having little effect on the flavor of the grape juice.

[0027] The method for creating an inert gas atmosphere is not particularly limited, but for example, the air inside the container can be pushed out and evacuated by supplying an inert gas into the container containing the grape must under pressure, thereby replacing the air.

[0028] The container is not particularly limited as long as it is one used in wine brewing, but since it will be filled with an inert gas, a tank equipped with a degassing valve is preferred. By providing the tank with a degassing valve, it is easy to adjust the oxygen concentration in the tank to a predetermined concentration.

[0029] The inert gas replacement device for creating an inert gas atmosphere is not particularly limited, and any known inert gas replacement device can be used. As the inert gas replacement device, a device that connects a high-pressure cylinder filled with inert gas and a tank equipped with a degassing valve by piping, and that can push out and exhaust air from the container by supplying the inert gas into the container containing the grape must, is preferred. The amount of inert gas supplied can be adjusted appropriately depending on the oxygen concentration in the tank.

[0030] ≪Forward osmosis membrane concentration process≫ In the forward osmosis membrane concentration step (hereinafter also referred to as the "FO membrane concentration step"), the grape juice from which the solids have been recovered is passed through a forward osmosis membrane in an inert gas atmosphere to concentrate the grape juice.

[0031] In the method for producing concentrated grape juice according to this embodiment, the grape juice from which the solids have been recovered is passed through a forward osmosis membrane, thereby enabling the grape juice to be concentrated without clogging the forward osmosis membrane. Furthermore, in the method for producing concentrated grape juice according to this embodiment, the grape juice can be concentrated while retaining its flavor and aroma by passing the juice through an FO membrane under an inert gas atmosphere.

[0032] In this specification, the term "forward osmosis membrane" refers to an FO membrane, a type of semipermeable membrane that allows water molecules to pass through but not molecules or ions above a certain size.

[0033] FO refers to the phenomenon where, when a solution with high osmotic pressure (hyperosmotic solution) and a solution with low osmotic pressure (hypoosmotic solution) are separated by a semipermeable membrane, only water permeates from the hypoosmotic solution to the hyperosmotic solution. In this case, the hypoosmotic solution is called the feed solution, and the hyperosmotic solution is called the draw solution (DS).

[0034] The solvent of the DS is preferably the same as the solvent of the treatment liquid, which in the case of use in winemaking is grape must. The solute of the DS is not particularly limited, but examples thereof include salts that are readily soluble in water; sugars such as sucrose, fructose, and glucose; monoalcohols such as methanol, ethanol, 1-propanol, and 2-propanol; glycols such as ethylene glycol and propylene glycol; polymers such as polyethylene oxide and propylene oxide; and copolymers of the above polymers.

[0035] The shape of the FO membrane may be a flat membrane, a hollow fiber membrane, or the like. In the FO membrane concentration step, it is preferable to use a modularized FO membrane, from the viewpoint of minimizing the equipment footprint.

[0036] When the FO membrane is flat, examples of the module form include pleated modules and spiral modules. When the FO membrane is hollow fiber, examples of the module form include hollow fiber membrane modules in which hollow fiber bundles are packed into a cylinder.

[0037] The hollow fiber membrane module in the FO membrane is not particularly limited as long as it can concentrate grape juice, but a hollow fiber membrane module that can maintain a higher water permeability (flux) is preferred. Examples include a hollow fiber membrane module made of cellulose triacetate and a hollow fiber membrane module made of a composite polyamide membrane with an aquaporin. More specifically, examples include the "HOLLOSEP® FO Membrane" manufactured by Toyobo MC Co., Ltd., and the "HFFO2" and "HFFO14" manufactured by AQUAPORINA. Of these, a hollow fiber membrane module made of a composite polyamide membrane with an aquaporin is more preferred, as shown in the examples below. In this specification, aquaporin refers to a protein that selectively allows only water molecules present on the surface of the cell membrane to pass through.

[0038] The concentration temperature of the grape juice in the FO membrane concentration step is not particularly limited as long as the components in the grape juice are not oxidized, but is preferably 0°C to 30°C, more preferably 5°C to 25°C, and even more preferably 10°C to 20°C.

[0039] The FO membrane concentration step may be started after the solid content recovery step is completed, or may be carried out in parallel with the solid content recovery step as long as the grape must necessary for the FO membrane concentration is not depleted.

[0040] The oxygen concentration in the inert gas atmosphere in the FO membrane concentration step may be the same as the oxygen concentration described in the above-mentioned <<Solid content recovery step>>, and is preferably 5.0 vol% or less, more preferably 1.0 vol% or less, and even more preferably 0.1 vol% or less.

[0041] Examples of inert gases used in the FO membrane concentration step include the same inert gases as those described in the above-mentioned <<Solids Recovery Step>>, and nitrogen is preferred from the viewpoint of having little effect on the flavor and aroma of the grape must.

[0042] Examples of a method for creating an inert gas atmosphere in the FO membrane concentration step include the same method as the method for creating an inert gas atmosphere described above in the <<Solids Recovery Step>>, and it is preferable to push out and evacuate the air in the container containing the grape must using the pressure of the inert gas supplied into the container.

[0043] Examples of the container include the same containers as those described above in the <<Solid content recovery step>>, and from the viewpoint of container cost and volume, a tank equipped with a deaeration valve is preferred.

[0044] The inert gas replacement device for creating an inert gas atmosphere may be the same as the inert gas replacement device in the above-mentioned <<Solid Content Recovery Step>>. A preferred device is one in which a high-pressure cylinder filled with inert gas is connected to a tank equipped with a degassing valve via piping, and the pressure of the inert gas supplied into the container containing the grape must is used to push out and evacuate the air inside the container.

[0045] In the FO membrane concentration process according to this embodiment, the only pressures that need to be applied from outside the system are those for transporting the grape must from which the solids have been recovered and the DS. The FO membrane concentration process according to this embodiment does not require concentration at the high operating pressures required in reverse osmosis membrane concentration, so one of its features is that clogging of the membrane caused by components in the grape must being adsorbed onto the membrane surface is minimal, resulting in a long membrane life.

[0046] (Solid content reduction process) The method for producing concentrated grape juice according to this embodiment may include, after the FO membrane concentration step, a solids reduction step in which the solids in the grape juice recovered in the solids recovery step are added to the concentrated grape juice.

[0047] The method for producing concentrated grape juice according to this embodiment can produce a concentrated grape juice containing the above-described solids while relatively increasing the sugar content compared to the grape juice before concentration by carrying out a solids reduction step. The solids contained in the concentrated grape juice can activate the activity of yeast in the "wine production method" described below.

[0048] The solid content introduced in the solid content reduction step may be the solid content precipitated in the solid content precipitation step or the solid content recovered in the filtration step, but the solid content precipitated in the solid content precipitation step and the solid content recovered in the filtration step are preferred, and the solid content recovered in the filtration step is more preferred.

[0049] The solid matter recovered in the solid matter recovery step may be entirely added to the concentrated grape juice, or a portion of the recovered solid matter may be added to the concentrated grape juice, but it is preferable to add the entirely recovered solid matter to the concentrated grape juice.

[0050] The timing of adding the solids recovered in the solid recovery step to the concentrated grape juice is not particularly limited as long as it is after the FO membrane concentration step is completed and before the production of wine, but it is preferable to add them immediately after the FO membrane concentration step is completed.

[0051] The method for adding the solids in the grape juice recovered in the solid recovery step to the concentrated grape juice is not particularly limited, but when the filtration method in the solid recovery step is dead-end filtration, the solids may be added as they are, or may be added together with the grape juice remaining in the solid recovery step. Alternatively, when the filtration method in the solid recovery step is cross-flow filtration, the filter may be backwashed with the filtered grape juice, and the solids adhering to the filter may be added to the concentrated grape juice.

[0052] <Concentrated grape juice> The components of the concentrated grape juice according to this embodiment will be described below.

[0053] (sugar content) In this specification, sugar content is a Brix value and refers to the amount of soluble solids measured at 20°C using a refractometer or a sugar refractometer (for example, the Anton Paar hydrometer "DMA 35" (trade name)).

[0054] The sugar content of the concentrated grape juice according to this embodiment is preferably 18.5 to 24.0, more preferably 19.5 to 23.0, and even more preferably 20.5 to 22.0. By concentrating using an FO membrane so that the sugar content falls within the above numerical range, wine with preserved flavor can be produced without adding sugar in the "wine production method" described below.

[0055] (total acidity) In this specification, the total acid value refers to the content of organic acids, and can be measured, for example, by the method described in the National Tax Agency's prescribed analytical method (National Tax Agency Ordinance No. 6 of 2007, revised June 22, 2007) for fruit liquor (9-10 total acid (free acid)).

[0056] The total acidity of the concentrated grape juice according to this embodiment is not particularly limited, but is preferably 5.0 mass / volume % to 8.0 mass / volume %. By concentrating the extract using an FO membrane so that the total acidity falls within the above range, the step of replenishing organic acids or the step of recovering organic acids becomes unnecessary in the "Wine production method" described below.

[0057] (organic acid) Examples of organic acids contained in the concentrated grape juice according to this embodiment include citric acid, tartaric acid, malic acid, succinic acid, lactic acid, acetic acid, etc. Furthermore, when the grape juice contains a large amount of malic acid, the sourness of the grape juice tends to be reduced.

[0058] The organic acid can be measured, for example, by gas chromatography-mass spectrometry (GC / MS).

[0059] (available nitrogen) As used herein, available nitrogen refers to the amount of nitrogen that can be utilized by yeast in wine brewing, and can be measured, for example, by the method described for sake (3-6 amino acids) in the National Tax Agency's analytical method (National Tax Agency Ordinance No. 6 of 2007, revised June 22, 2007).

[0060] (pH) The pH of the concentrated grape juice according to this embodiment is not particularly limited, but is preferably 2.7 to 4.2, more preferably 2.9 to 3.8, and even more preferably 3.1 to 3.5.

[0061] The pH can be measured using a commercially available pH measuring device.

[0062] (color tone) The color tone of the concentrated grape juice according to this embodiment can be measured, for example, by the method described in the section on fruit wines (9-11 coloring degree) in the National Tax Agency's prescribed analytical methods (National Tax Agency Ordinance No. 6 of 2007, revised June 22, 2007).

[0063] <Wine production method> The method for producing wine according to this embodiment is a method for producing wine using concentrated grape juice obtained by the above-mentioned <Method for producing concentrated grape juice>. The method for producing wine according to this embodiment includes the following fermentation step and solids recovery step.

[0064] <Fermentation process> The various fermentation conditions in the fermentation step are not particularly limited and are appropriately selected to obtain the desired wine quality.

[0065] <Solid content recovery process> Wine production typically includes a step of recovering solids from the wine after yeast fermentation has finished and before filling into containers. Methods for recovering solids from wine include those described in the "Solids Recovery Step" section of the "Method for Producing Concentrated Grape Juice" above. The filter used to recover solids from wine is preferably one with a mesh size large enough to recover tartar and sediment components from the wine. A preliminary experiment may be conducted using the grape juice to be treated, and a filter with openings that can adequately recover tartar and sediment components may be selected.

[0066] <Wine> The components of the wine according to this embodiment will be described below.

[0067] The total acidity and pH can be measured in the same manner as described in the above section "Concentrated Grape Must."

[0068] (total acidity) The total acidity of the wine according to this embodiment is not particularly limited, but is preferably 5.0 mass / volume % to 8.0 mass / volume %.

[0069] (pH) The pH of the wine according to this embodiment is not particularly limited, but is preferably 2.7 to 4.2, more preferably 2.9 to 3.8, and even more preferably 3.1 to 3.5.

[0070] (Alcohol content) The alcohol content of wine can be measured, for example, by the method described for fruit wine in the National Tax Agency's prescribed analytical method (National Tax Agency Ordinance No. 6 of 2007, revised June 22, 2007).

[0071] (extract) In this specification, the extract content refers to the number of grams of non-volatile components contained in 100 cubic centimeters of original volume at a temperature of 15° C. For example, it can be calculated by the method described in the National Tax Agency's prescribed analytical method for fruit wine (National Tax Agency Ordinance No. 6 of 2007, revised June 22, 2007).

[0072] The extract content of the wine according to this embodiment is preferably 1.8 mass / volume % to 2.5 mass / volume %, and more preferably 2.0 mass / volume % to 2.3 mass / volume %.

[0073] According to the method for producing wine according to this embodiment, wine with preserved flavor can be obtained from concentrated grape juice with preserved flavor.

[0074] <Quality of concentrated grape juice and wine> As shown in Table 1, the concentrated grape juice and wine obtained by the production method according to this embodiment have sugar content, alcohol content, and flavor comparable to those of wines made from mature grapes that do not require sugar addition.

[0075] As shown in Table 1, when unripe grapes are grown in Japan, where the growing environment is unfavorable, and harvested when the sugar content is low, the concentrated grape juice and wine obtained without sugar addition or concentration have low sugar content, alcohol content, and flavor. When immature grapes are used as the raw material, the desired sugar content and alcohol content can be achieved by adding sugar, but the flavor is relatively low compared to the sugar content. In addition, by using conventional concentration methods (vacuum concentration or reverse osmosis membrane concentration) without adding sugar, it is possible to obtain the desired sugar content and alcohol content even when using immature grapes as the raw material, but the concentration reduces the aroma and flavor.

[0076] By using the production method according to this embodiment, even when unripe grapes are used as the raw material, the flavor can be maintained because there is no need to use sugar addition or conventional concentration methods.

[0077] [Table 1]

[0078] <Production system used in the production of concentrated grape juice and wine> FIG. 1 is a schematic diagram showing an example of a production system used in a method for producing concentrated grape juice according to this embodiment and wine using the concentrated grape juice as a raw material.

[0079] The apparatus 10 for producing concentrated grape must and wine includes a first storage tank 2 having a first replacement device 1, a recovery device 3, a second storage tank 5 having a second replacement device 4, an FO membrane concentrator 6, and a second recovery device 7. The second storage tank 5 has the FO membrane concentrator 6 on a circulation line for the concentrated grape must.

[0080] The first replacement device 1 is not particularly limited, and examples thereof include the inert gas replacement device exemplified in the <Solids recovery step> in the above <Method for producing concentrated grape juice>.

[0081] The first storage tank 2 is not particularly limited, and any known tank used in wine brewing can be used. Examples of the first storage tank 2 include the containers exemplified in the "Solids Recovery Step" section of the above-mentioned "Method for Producing Concentrated Grape Juice." From the standpoints of container cost and volume, a tank equipped with a deaeration valve is preferred. The first storage tank 2 may be provided with a recovery device for recovering solid matter that has settled in the lower part of the first storage tank 2.

[0082] The first recovery device 3 can be a filter similar to that described in the <Solids Recovery Step> in the above-mentioned <Method for Producing Concentrated Grape Juice>. From the viewpoint of preventing clogging of the FO membrane in the FO membrane concentrator 6, a filter with a mesh size that can recover tartar and sediment components in the grape juice is preferred.

[0083] The second replacement device 4 is not particularly limited, and examples thereof include the inert gas devices exemplified in the above <FO membrane concentration step>.

[0084] Examples of the second storage tank 5 include the containers exemplified in the <FO membrane concentration step> section of the above <Method for producing concentrated grape juice>. From the viewpoints of container cost and volume, a tank equipped with a deaeration valve is preferred. Although not shown in FIG. 1, a tank dedicated to fermentation may be provided downstream of the second storage tank 5.

[0085] The FO membrane described in the above <FO membrane concentration step> can be used as the FO membrane concentrator 6, and from the viewpoint of minimizing the equipment footprint, it is preferable to use a modularized FO membrane.

[0086] The second recovery device 7 can be the same as that described in the "Solid recovery step" in the "Wine production method" above, and is preferably one with a mesh size that can recover the sediment components in the wine.

[0087] A method for producing concentrated grape juice and wine using the concentrated grape juice and wine production apparatus 10 will be described below.

[0088] First, an inert gas IG is supplied from a first replacement device 1 to a first storage tank 2 containing grape juice A1, thereby creating an inert gas IG atmosphere inside the first storage tank 2.

[0089] Next, in the first storage tank 2, the grape juice A1 is allowed to stand under an inert gas IG atmosphere to allow the solid content X to settle. Next, the grape juice A1 (A2, X) from which the solid content X has precipitated is passed through the first recovery device 3, and the grape juice A2 from which the solid content X has been recovered is introduced into the second storage tank 5.

[0090] Next, the grape juice A2 from which the solid content X has been recovered is passed through an FO membrane concentrator 6 on the circulation line under an inert gas IG atmosphere to obtain concentrated grape juice A3. The solid content X precipitated in the first storage tank 2 and the solid content X recovered in the first recovery device 3 may be added to the obtained concentrated grape juice A3.

[0091] Next, the concentrated grape juice A3 to which the solid content X has been added is fermented in the second storage tank 5. After the fermentation is completed, the wine W1 containing the solid content X is passed through the second recovery device 7, and the solid content X is recovered to obtain the wine W2.

[0092] FIG. 2 is a schematic diagram showing an example of a production system used in the method for producing concentrated grape juice according to this embodiment and wine using the concentrated grape juice as a raw material.

[0093] The concentrated grape must and wine production apparatus 11 includes a storage tank 8 having a replacement device 1, a first recovery device (cross-flow filtration type) 9, an FO membrane concentration device 6, and a second recovery device 7.

[0094] The replacement device 1 is the same as the first replacement device 1 in FIG. 1 described above.

[0095] The storage tank 8 is not particularly limited, and any known tank used in wine brewing can be used. Examples of the storage tank 8 include those exemplified as the containers described in the "Solids Recovery Step" section of the above-mentioned "Method for Producing Concentrated Grape Juice." From the viewpoints of container cost and volume, a tank equipped with a deaeration valve is preferred. Although not shown in FIG. 2, a tank dedicated to fermentation may be provided downstream of the storage tank 8.

[0096] The same filter as that described in the <Solids Recovery Step> in the above-mentioned <Method for Producing Concentrated Grape Juice> can be used as the recovery device (cross-flow filtration type) 9. From the viewpoint of preventing clogging of the FO membrane in the FO membrane concentrator 6, the filter preferably has a mesh size that allows recovery of tartar and sediment components in the grape juice.

[0097] In order to accommodate tartar and sediment components of various sizes, it is preferable to use multiple filters with different mesh sizes as the recovery device (cross-flow filtration type) 9. Specifically, as shown in Fig. 3, when two types of filters with different mesh sizes are used, it is more preferable to use the filters with larger mesh sizes as the front-stage filters 91, 92, and to filter the grape juice filtered through the front-stage filters 91, 92 through the rear-stage filter 93 with smaller mesh sizes than the front-stage filters 91, 92. It is preferable to use the front-stage filters 91, 92 in parallel in order to reduce the risk of clogging with tartar and sediment components.

[0098] The FO membrane concentrator 6 is the same as the FO membrane concentrator 6 in FIG. 1 described above.

[0099] The second recovery device 7 is the same as the second recovery device 7 in FIG.

[0100] A method for producing concentrated grape juice and wine using the concentrated grape juice and wine production apparatus 11 will be described below.

[0101] First, an inert gas IG is supplied from the replacement device 1 to a storage tank 11 containing grape juice A1, thereby creating an inert gas IG atmosphere inside the storage tank 11. The grape juice A1 may be allowed to stand in the storage tank 11 to allow the solid content X to precipitate.

[0102] Next, the grape juice A1(X) is passed through a recovery device (cross-flow filtration type) 9, and the filtered grape juice A2 is passed through an FO membrane concentrator 6 to obtain concentrated grape juice A3.

[0103] The obtained concentrated grape juice A3 is returned to the storage tank 8. In addition, the grape juice A1(X) that was not filtered in the recovery device (cross-flow filtration type) 9 is also returned to the storage tank 8. This circulation is continued until the Brix of the grape juice in the storage tank 8 reaches the target value.

[0104] The resulting concentrated grape juice A3 is then fermented in a storage tank 8. After fermentation is complete, the wine W1 containing the solid content X is passed through a second recovery device 7, and the solid content X is recovered to obtain a wine W2. [Example]

[0105] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0106] [Example 1] The grape must was concentrated using an FO membrane to produce concentrated grape must.

[0107] First, a storage tank containing 1,200 L of grape juice with a Brix of 16.6 was purged under a nitrogen atmosphere. The grape juice was then passed through a filter to recover the solids. The filtered grape juice was then placed in a grape juice circulation tank and circulated through an FO membrane (manufactured by AQUAPORIN, product name "HFFO14," number of membranes: 3). FO membrane concentration was continued under a nitrogen atmosphere for 7 hours until the Brix of the grape juice reached 21.5.

[0108] After the Brix of the grape juice reached 21.5, the solids recovered by the filter and the grape juice before concentration, including the sediment at the bottom of the supply tank, were added to the grape juice with a Brix of 21.5, yielding 930 L of concentrated grape juice with a Brix of 20.2.

[0109] The specific gravity, Brix, total acidity, available nitrogen, pH, color, and organic acids of the grape must were measured before concentration, at the maximum concentration point (peak value in Table 2), and after concentration. The results are shown in Table 2. While the sugars and organic acids of the grape must were concentrated by FO membrane concentration, no decrease in pH was observed. In addition, sensory evaluation by five experts with high ability to distinguish between the flavors of grape must and wine revealed that the resulting concentrated grape must had strong melon and vanilla aromas. This demonstrates that by taking measures to prevent oxidation and control solids during FO membrane concentration of grape must, concentrated grape must that retains its flavor without the need for chaptalization.

[0110] [Table 2]

[0111] [Example 2] The concentrated grape juice obtained in Example 1 was used to brew wine in a conventional manner.

[0112] The specific gravity, pH, total acidity, alcohol content, and extract content of the resulting wine were measured. The results are shown in Table 3. The concentrated grape juice obtained in Example 1 was fermented with yeast to obtain a wine with an alcohol content of 11.7 volume / volume%. In addition, as a result of sensory evaluation by the same five experts as in Example 1, the resulting wine had strong melon and vanilla aromas, similar to the concentrated grape juice obtained in Example 1. These results demonstrate that a flavorful wine can be obtained from concentrated grape must, which retains its flavor without adding sugar.

[0113] [Table 3]

[0114] [Example 3] Using the equipment flow shown in Figure 2, grape must was concentrated using an FO membrane to produce concentrated grape must.

[0115] First, a storage tank containing 1,302 L of grape juice with a Brix of 14.5 was purged with nitrogen. The grape juice was then passed through a cross-flow filtration system as shown in Figure 3, and the solids in the grape juice were collected. The filtered grape juice was then passed through FO membranes (manufactured by AQUAPORIN, product name "HFFO14", number of membranes: 3) and circulated through a storage tank.

[0116] Next, solid recovery and FO membrane concentration were continued under a nitrogen atmosphere for 4 hours and 50 minutes until the Brix of the grape juice reached 21.0, yielding 872 L of concentrated grape juice.

[0117] The specific gravity, Brix, pH, total acidity, available nitrogen, tartaric acid, and malic acid of the grape must were measured before and after concentration. The results are shown in Table 4. While the sugars and organic acids of the grape must were concentrated by FO membrane concentration, no decrease in the pH of the grape must was confirmed by FO membrane concentration. Furthermore, the values ​​of tartaric acid, malic acid, and available nitrogen were higher than those of the concentrated grape must in Example 1. Furthermore, the values ​​of tartaric acid, malic acid, and available nitrogen were higher than those of the concentrated grape must in Example 1. Furthermore, although the same yeast was used in both Examples 1 and 3, the concentrated grape must obtained in Example 3 had a stronger citrus aroma and a more pronounced acidity due to its higher malic acid and tartaric acid values. These findings demonstrate that cross-flow filtration can be used to produce concentrated grape must that retains its flavor without the need for sugar chaptalization. Furthermore, the use of concentrated grape must with a high available nitrogen content can further activate the yeast, resulting in a wine with a richer flavor.

[0118] [Table 4]

[0119] The above results demonstrate that by taking measures to prevent oxidation and control solids content during the FO membrane concentration of grape must, it is possible to produce a concentrated grape must with the required sugar content and that retains its flavor and aroma, without the need for sugar addition, and to produce wine using this concentrated grape must. [Industrial Applicability]

[0120] According to the present invention, it is possible to provide a method for producing concentrated grape juice having a required sugar content and retaining flavor and aroma, and a method for producing wine using the concentrated grape juice. [Explanation of symbols]

[0121] 1...first replacement device, replacement device, 2...first storage tank, 3...first recovery device, 4...second replacement device, 5...second storage tank, 6...FO membrane concentration device, 7...second recovery device, A1...grape must, A2...grape must from which solids have been recovered, A3...concentrated grape must, W1...wine containing solids, IG...inert gas, X...solids, 10...apparatus for producing concentrated grape must and wine, 11...apparatus for producing concentrated grape must and wine, 8...storage tank, 9...cross-flow filtration recovery device, 91, 92...pre-stage filters, 93...post-stage filter

Claims

1. a solids recovery step of recovering solids in the grape juice under an inert gas atmosphere; a forward osmosis membrane concentration step of concentrating the grape juice from which the solid content has been recovered by passing the grape juice through a forward osmosis membrane under an inert gas atmosphere; A method for producing concentrated grape must, comprising:

2. 2. The method for producing concentrated grape juice according to claim 1, wherein the forward osmosis membrane is a hollow fiber membrane module in which hollow fiber forward osmosis membranes are modularized.

3. The method for producing concentrated grape juice according to claim 1 or 2, wherein the solid content recovery step includes a filtration step of filtering the grape juice.

4. The method for producing concentrated grape juice according to claim 3, wherein the grape juice is filtered by a cross-flow method in the filtering step.

5. 3. The method for producing concentrated grape must according to claim 1, wherein the inert gas is nitrogen, argon, carbon dioxide, or a mixture thereof.

6. The method for producing concentrated grape juice according to claim 1 or 2, wherein the solid content includes a sediment component.

7. The method for producing concentrated grape juice according to claim 1 or 2, wherein the sugar content of the concentrated grape juice is 18.5 to 24.

0.

8. A method for producing wine, comprising yeast fermentation using concentrated grape must obtained by the method according to claim 1 or 2.

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