JP7252790B2 - Filtration and clarification method for fruit wine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing fruit liquor, including filtration and clarification steps for fruit liquor using a porous membrane. More specifically, the present invention relates to a method for producing a fruit wine that includes a filtration/clarification step using a porous membrane for removing aggregates from a fruit wine containing yeast or lees after fermentation, wherein The present invention relates to a method in which the change in chromaticity components is small, the removal rate of sediment components is high, and the recovery of the water permeation amount after the washing process of the porous membrane and the washing solution (chemical solution) resistance are high.

Conventionally, fruit wines are produced by preparing fruit raw materials and going through fermentation, clarification, and aging processes, and there are a wide variety of factors required to stabilize the quality. For example, in the case of red wine, stabilizing the color tone is important from the viewpoint of quality maintenance. In addition, darker red wines tend to be preferred by consumers because of their higher quality and richer content of useful ingredients such as anthocyanins.
The chromaticity of red wine is greatly influenced by the variety of grapes used as raw materials and the growing environment. For example, Cabernet Sauvignon and Merlot, which are representative varieties of red wine, are known as varieties that can express a deep red color. , the chromaticity may not be as high as expected.
Even with white wine, the chromaticity of the produced wine changes depending on the variety of raw materials, the region where it is cultivated, and the weather. In the case of white wine, some brands set a certain lower limit for chromaticity from the viewpoint of production control. As with red wine, chromaticity mainly depends on raw materials, so it may be difficult to always ensure a certain level of chromaticity.
In order to solve such problems related to color tone and chromaticity, a method of applying ultrasonic waves at any point before or during the brewing (hereinafter, see Patent Document 1), or adding pectinase to the raw material of wine and adding grape skins has been reported (hereinafter, see Patent Document 2).

JP-A-2001-258540 JP-A-11-46747

However, when ultrasonic waves are applied, the color components in the pericarp can be efficiently eluted, but other useful components may be decomposed. Moreover, although the addition of pectinase can promote the elution of color components, it is complicated in that the amount of addition must be adjusted for each raw material.
As a result of extensive studies and repeated experiments, the inventors of the present invention have found that the factors that determine the chromaticity of fruit wines are the raw materials and the chromaticity components from the raw materials. It was found that it is affected not only by the extraction method of , but also by the subsequent manufacturing process. Among them, in diatomaceous earth filtration, which is conventionally used to clarify fruit wine after alcohol fermentation, a considerable amount of components related to color are adsorbed, and the color after filtration is lower than before filtration. I found a new problem.

On the other hand, in recent years, a membrane filtration method has been reported as a turbidity removal method that can replace diatomaceous earth filtration. Advantages of the membrane filtration method include: (1) high level of turbidity in the obtained water quality and stability (obtained water is highly safe); (3) easy automatic operation; and (4) reduction in disposal costs for used diatomaceous earth. For the clarification operation by membrane filtration, a flat membrane or hollow fiber porous ultrafiltration membrane or microfiltration membrane having an average pore size in the range of several nanometers to several hundred nanometers is used. As described above, the clarification operation by the membrane filtration method has many advantages that the diatomaceous earth filtration does not have. Therefore, it is being adopted for various filtration applications as an alternative or complementary means to the conventional method.
However, when a porous filtration membrane is produced from a resin material, if the film-forming method is different, the microstructure of the material constituting the membrane will differ. In addition, in the filtration for removing the sediment contained in the fermented fruit wine, it is required to keep the sediment removal rate high while suppressing the deterioration of the aforementioned color components as much as possible. Furthermore, since the membrane usually clogs if the filtration operation is continued, the operation of the filtration method using the porous filtration membrane is accompanied by a washing step. On the other hand, the use of chemicals in the cleaning process induces deterioration of membrane strength. At this time, if there is a difference in the microstructure of the materials that make up the porous filtration membrane, the degree of damage to the porous filtration membrane caused by the cleaning solution (chemical solution) used in the repeated cleaning process will differ. There is also the issue of impact.

In view of such problems, the problem to be solved by the present invention is to provide a fruit liquor containing agglomerates of sediment components after fermentation, which includes a filtration and clarification process using a porous membrane for removing the agglomerates. To provide a method for producing sake in which the change in chromaticity components before and after filtration is low, the sediment component removal rate is high, and the water permeation recoverability and washing solution (chemical solution) resistance after the washing process of a porous membrane are high. is.

The present inventors have made intensive studies and repeated experiments to solve the above-mentioned problems, and as a result, the pores from the inside of the membrane, which is the liquid to be treated side of the porous filtration membrane, to the outside of the membrane, which is the filtrate side. In a method for producing fruit liquor including a filtration step using a porous membrane for removing aggregates of lees from fruit liquor containing aggregates of sediment components by using a membrane with good communication properties, before and after filtration The change in color components of fruit wine is low, the sediment removal rate is high, and the cleaning solution (chemical solution) used in the cleaning process is hot water at 50 ° C. to 90 ° C. and / or 0.05% by weight or more. Deterioration of the membrane can be minimized even when an aqueous solution containing 5% by weight or less of sodium hypochlorite or 0.4% to 4% by weight of sodium hydroxide is used. was unexpectedly discovered, and the present invention was completed.

That is, the present invention is as follows.
[1] the following steps:
A fermentation step of fermenting fruit to obtain a fruit wine containing aggregates of sediment components; a filtration/clarification step of separating the filtrate from the aggregates of the sediment components;
A method for producing a fruit wine comprising
In the SEM image of the membrane cross section in the film thickness direction perpendicular to the inner surface of the porous membrane, a field of view including the inner surface, a field of view including the outer surface of the membrane, and a field of view including the outer surface of the membrane, and photographed at equal intervals between these fields 2 The total area of the resin portion having an area of 1 μm ² or less is 70% or more of the total area of the resin portion in each region of a total of 4 fields of view, and
When X1 is the absorbance of the fruit wine before the filtration/clarification step and X2 is the absorbance of the fruit wine after the filtration/clarification step at an arbitrary wavelength of 250 nm to 650 nm, X2/X1≧0.75. fulfill a relationship,
A method for producing a fruit liquor characterized by:
[2] the following steps:
A fermentation step of fermenting fruit to obtain a fruit wine containing aggregates of sediment components; a filtration/clarification step of separating the filtrate from the aggregates of the sediment components;
A method for producing a fruit wine comprising
In the SEM image of the membrane cross section in the film thickness direction perpendicular to the inner surface of the porous membrane, a field of view including the inner surface, a field of view including the outer surface of the membrane, and a field of view including the outer surface of the membrane, and photographed at equal intervals between these fields 2 In each region of a total of 4 fields of view, the total area of the resin part having an area of 10 μm ² or more is 15% or less of the total area of the resin part, and at any wavelength of 250 nm to 650 nm, When the absorbance of the fruit wine before the filtration/clarification step is X1 and the absorbance of the fruit wine after the filtration/clarification step is X2, the relationship X2/X1≧0.75 is satisfied.
A method for producing a fruit liquor characterized by:
[3] the following steps:
A fermentation step of fermenting fruit to obtain a fruit wine containing aggregates of sediment components; a filtration/clarification step of separating the filtrate from the aggregates of the sediment components;
A method for producing a fruit wine comprising
In the SEM image of the membrane cross section in the film thickness direction perpendicular to the inner surface of the porous membrane, a field of view including the inner surface, a field of view including the outer surface of the membrane, and a field of view including the outer surface of the membrane, and photographed at equal intervals between these fields 2 In each region of a total of four visual fields, the total area of the resin portion having an area of 1 μm ² or less is 70% or more of the total area of the resin portion, and the resin has an area of 10 μm ² or more. The total area of the resin portion is 15% or less with respect to the total area of the resin portion, and the absorbance of the fruit wine before the filtration/clarification step at an arbitrary wavelength of 250 nm to 650 nm is X1, and the filtration/clarification step is X1. When the absorbance of the fruit wine after the clarification step is X2, the relationship X2/X1≧0.75 is satisfied.
A method for producing a fruit liquor characterized by:
[4] The porous membrane has a field of view including the inner surface, a field of view including the outer surface of the membrane, and a field of view of these in an SEM image of the membrane cross section in the film thickness direction perpendicular to the inner surface of the porous membrane. The total area of the resin portion having an area of more than 1 μm ² and less than 10 μm ² in each region of a total of 4 fields of view taken at equal intervals between 2 fields is 15% or less of the total area of the resin part The method according to any one of [1] to [3] above.
[5] In the filtration/clarification step, a mixture of fruit wine and bentonite obtained in the fermentation step is passed through a porous membrane composed of a resin having a three-dimensional network structure, and the above [1] to [ 4].
[6] The method according to any one of [1] to [5], wherein the porous membrane has a surface open area ratio of 25 to 60%.
[7] The method according to any one of [1] to [6], wherein the porous membrane is a hollow fiber membrane.
[8] The method according to any one of [1] to [7] above, wherein the resin constituting the porous membrane is a thermoplastic resin.
[9] The method according to [8], wherein the thermoplastic resin is a fluororesin.
[10] The fluororesin includes vinylidene fluoride resin (PVDF), chlorotrifluoroethylene resin, tetrafluoroethylene resin, ethylene-tetrafluoroethylene copolymer (ETFE), ethylene-monochlorotrifluoroethylene copolymer (ECTFE ), a hexafluoropropylene resin, and a mixture of these resins.
[11] The method according to [8], wherein the thermoplastic resin is polyethylene (PE).
[12] After the filtration/clarification step, the cleaning step further comprises passing or immersing a cleaning liquid through the porous membrane to clean the inside of the porous membrane, wherein the cleaning liquid is hot water of 50°C to 90°C. The method according to any one of [1] to [11] above.
[13] After the filtration/clarification step, the cleaning step further includes passing or immersing a cleaning liquid through the porous membrane to clean the inside of the porous membrane, wherein the cleaning liquid is 0.05% by weight or more. The method according to any one of [1] to [11] above, which is an aqueous solution containing sodium hypochlorite at 0.5 wt% or less or sodium hydroxide at 0.4 wt% or more and 4 wt% or less.
[14] The relationship between the tensile elongation at break E0 of the porous membrane before the washing step and the tensile elongation at break E1 of the porous membrane after the washing step is E1/E0×100≧80%. , the method according to the above [12] or [13].
[15] The tensile elongation at break E0 of the porous membrane before the washing step and the porous membrane after repeating the washing step X times (where X is an integer of 2 to 100) The method according to the above [12] or [13], wherein the relationship with the tensile elongation at break EX is EX/E0×100≧70%.
[16] The above [ 12] or the method according to [13].
[17] The flux L0 of the porous membrane before the filtration/clarification step and the flux of the porous membrane after repeating the washing step X times (where X is an integer of 2 to 100) The method according to the above [12] or [13], wherein the relationship with the flux LX is X/L0×100≧90%.
[18] The above-mentioned [12] to [17], wherein the cleaning step includes a cleaning liquid step of performing cleaning with the cleaning liquid, and then a rinsing step of performing rinsing with rinse water to remove remaining cleaning liquid components. Any method described.
[19] The method according to [18] above, wherein the amount of rinsing water used in the rinsing step is 100 L/m ² or less per unit area of the porous membrane.
[20] The above [18], wherein the chlorine concentration in the filtrate after restarting the filtering/clarification step after the rinsing step is 0.1 ppm or less, and the pH of the filtrate is 8.6 or less. ] or the method according to [19].

In the filtration/clarification step in the method for producing fruit wine according to the present invention, the communication of pores from the inside of the porous filtration membrane, which is the side of the liquid to be treated, to the outside of the membrane, which is the side of the filtrate, is good. Since a membrane is used, the change in color of the fruit wine before and after filtration is low, and the sediment removal rate is high. Or even when using an aqueous solution containing 0.05% to 0.5% by weight of sodium hypochlorite or 0.4% to 4% by weight of sodium hydroxide, deterioration of the membrane can be minimized. Therefore, the method for producing a fruit wine according to the present invention is excellent in filtration performance, its recoverability, and chemical resistance, and has a long life. Specifically, since the porous membrane used in the filtration/clarification step in the method for producing fruit wine according to the present invention has high pore continuity, the chromaticity components of the fruit wine are less adsorbed to the membrane, and there is less 25% or less, and the sediment removal rate is over 95%. Furthermore, even when an aqueous solution of sodium hydroxide having a relatively low concentration of 4% by weight is used as the washing liquid in the washing step, the water permeation rate of the porous membrane can be sufficiently recovered.

It is an example of a SEM image of a cross section of a porous membrane used in the filtration/clarification step in the method for producing fruit wine according to the present embodiment (black portions indicate resin, white portions indicate pores (pores)). In the SEM image of the film cross section in the film thickness direction perpendicular to the inner surface of the porous film used in Example 1, a field of view including the inner surface, a field of view including the outer surface of the film, and between these fields of view, etc. 2 is a histogram showing the ratio (%) of the total area of a resin portion having a predetermined area to the total area of a resin portion in each region (circles 1 to 4) of a total of 4 fields of view of 2 fields photographed at intervals. In the SEM image of the membrane cross section in the film thickness direction perpendicular to the inner surface of the porous membrane used in Example 2, a field of view including the inner surface, a field of view including the outer surface of the membrane, and between these fields of view, etc. 2 is a histogram showing the ratio (%) of the total area of a resin portion having a predetermined area to the total area of a resin portion in each region (circles 1 to 4) of a total of 4 fields of view of 2 fields photographed at intervals. In the SEM image of the film cross section in the film thickness direction perpendicular to the inner surface of the porous film used in Example 3, a field of view including the inner surface, a field of view including the outer surface of the film, and between these fields of view, etc. 2 is a histogram showing the ratio (%) of the total area of a resin portion having a predetermined area to the total area of a resin portion in each region (circles 1 to 4) of a total of 4 fields of view of 2 fields photographed at intervals. In the SEM image of the membrane cross section in the film thickness direction perpendicular to the inner surface of the porous membrane used in Comparative Example 3, a field of view including the inner surface, a field of view including the outer surface of the membrane, and between these fields of view, etc. 2 is a histogram showing the ratio (%) of the total area of a resin portion having a predetermined area to the total area of a resin portion in each region (circles 1 to 4) of a total of 4 fields of view of 2 fields photographed at intervals.

Hereinafter, embodiments of the present invention (hereinafter also referred to as present embodiments) will be described in detail. It should be noted that the present invention is not limited to this embodiment.

<Method for producing fruit wine>
The method for producing fruit liquor of the present embodiment includes the following steps:
A fermentation step of fermenting fruit to obtain a fruit wine containing aggregates of sediment components; a filtration/clarification step of separating the filtrate from the aggregates of the sediment components;
A method for producing a fruit wine comprising
In the SEM image of the membrane cross section in the film thickness direction perpendicular to the inner surface of the porous membrane, a field of view including the inner surface, a field of view including the outer surface of the membrane, and a field of view including the outer surface of the membrane, and photographed at equal intervals between these fields 2 The total area of the resin portion having an area of 1 μm ² or less is 70% or more of the total area of the resin portion in each region of a total of 4 fields of view, and
When X1 is the absorbance of the fruit wine before the filtration/clarification step and X2 is the absorbance of the fruit wine after the filtration/clarification step at an arbitrary wavelength of 250 nm to 650 nm, X2/X1≧0.75. fulfill a relationship,
It is characterized by
X2/X1≧0.85 is preferred, and X2/X1≧0.9 is more preferred.
The shape of the porous membrane is not particularly limited, and may be a flat membrane, a tubular membrane, or a hollow fiber membrane. Hollow fiber membranes are preferred because they can be

As the filtration step in the method for producing a fruit wine according to the present embodiment, for example, a fruit wine (liquid to be treated) containing an aggregate of sediment components aggregated by fermentation in the hollow portion (inner surface) of the porous hollow fiber membrane is filtered. It may be a so-called internal pressure filtration step in which the liquid is supplied, passed through the film thickness (thickness) part of the porous hollow fiber membrane, and the liquid oozing out from the outer surface of the porous hollow fiber membrane is taken out as filtrate. However, even in a so-called external pressure filtration process in which the liquid to be treated is supplied from the outer surface of the porous hollow fiber membrane, and the filtrate oozing out from the inner surface of the porous hollow fiber membrane is taken out through the hollow part. good. Examples of types of fruit wine include red wine, white wine, cider (apple wine), apricot wine, yuzu wine, and plum wine, but are not limited to these. Nor is there any limitation with respect to the clarification of soft drinks that do not involve a brewing process.
As used herein, the term "inside the porous membrane" refers to a membrane (thickness) portion in which a large number of pores are formed.

Preferably, the method for producing fruit wine of the present embodiment further includes a washing step of passing or immersing a washing liquid through the porous membrane to wash the inside of the porous membrane after the filtration/clarification step. , the washing liquid may be hot water of 50° C. to 90° C. (hereinafter also referred to as hot water).
More preferably, the method for producing a fruit wine of the present embodiment further includes a washing step of passing or immersing a washing liquid through the porous membrane to wash the inside of the porous membrane after the filtration/clarification step. an aqueous solution containing 0.05% by weight or more and 0.5% by weight or less of sodium hypochlorite or 0.4% by weight or more and 4% by weight or less of sodium hydroxide (hereinafter also referred to as a chemical solution) can be In the cleaning step, it is preferable to carry out chemical cleaning after hot water cleaning.
The cleaning step can include a cleaning liquid step of cleaning with the cleaning liquid, and then a rinse step of rinsing with rinse water to remove remaining cleaning liquid components. When the cleaning liquid is hot water, the temperature of the hot water can be preferably 55°C or higher and 85°C or lower, more preferably 60°C or higher and 80°C or lower. When the cleaning liquid is the chemical solution, the temperature of the chemical solution is preferably 15° C. or higher and 35° C. or lower, more preferably 20° C. or higher and 35° C. or lower. Further, the concentration of sodium hydroxide in the chemical solution is more preferably 0.7% by weight or more and 4% by weight or less, and further preferably 1% by weight or more and 4% by weight or less. The concentration of sodium hypochlorite in the chemical solution is more preferably 0.1% by weight or more and 0.5% by weight or less, and further preferably 0.2% by weight or more and 0.5% by weight or less. In the washing process, for example, the washing liquid is passed through in the direction opposite to the flow direction of the fruit wine in the filtration process, that is, from the filtrate side to the concentrate side, thereby removing deposits from the filtration surface (concentrate side surface) of the porous membrane. (Insoluble components) are separated and removed by reverse pressure water washing, and air scrubbing is used to shake off the insoluble components adhering to the porous membrane by shaking the porous membrane with air. The amount of rinsing water used in the rinsing step is preferably 100 L/m ² or less, more preferably 50 L/m ² or less per unit area of the porous membrane. Further, it is preferable that the chlorine concentration in the filtrate after restarting the filtering step after the rinsing step is 0.1 ppm or less and the pH of the filtrate is 8.6 or less.
A filter aid may be added in advance to the stock solution before the filtration/clarification step. Examples of filter aids include activated carbon, polyvinylpolypyrrolidone (PVPP), colloidal silica, bentonite, and the like. The concentration at the time of addition depends on the type of the stock solution, but can be appropriately adjusted between about 50 ppm and 5000 ppm. If the concentration at the time of addition is too low, the aggregation effect may not be sufficient. Also, if the concentration at the time of addition is too high, it may have an adverse effect on filtration. Although the size of the filter aid depends on the substance to be adsorbed, it is preferable to use a filter aid that is large enough to clog the pores of the hollow fiber membrane and that does not easily scratch the surface of the hollow fiber membrane.
The structure, raw material (material), and manufacturing method of the porous membrane used in the filtration step in the method for producing fruit wine according to the present embodiment will be described in detail below.

<Porous membrane>
The porous membrane has a field of view including the inner surface, a field of view including the outer surface of the membrane, a field of view including the outer surface of the membrane, and a field between these fields in an SEM image of a membrane cross section in the film thickness direction perpendicular to the inner surface of the porous membrane. In each area of a total of 4 fields of 2 fields photographed at intervals, the total area of the resin part having an area of 1 μm ² or less is 70% or more of the total area of the resin part; , the total area of the resin parts having an area of 10 μm ² or more is 15% or less of the total area of the resin parts; the total area of the resin parts having an area of 1 μm ² or less in each region is 70% or more of the total area of the resin parts, and the total area of the resin parts having an area of 10 μm ² or more is 15% or less of the total area of the resin parts; is either In a preferred porous membrane, the total area of the resin portions having an area of 1 μm ² or less in each region is 70% or more of the total area of the resin portions, and the area is more than 1 μm ² and less than 10 μm ² . The total area of the resin portions is 15% or less of the total area of the resin portions, and the total area of the resin portions having an area of 10 μm2 ^or more is the total area of the resin portions 15% or less.

FIG. 1 is an example of a cross-sectional SEM image of a porous membrane used in the filtration/clarification step in the method for producing fruit wine according to the present embodiment. Such an SEM image is a field of view including the inner surface, a field of view including the outer surface of the membrane, and a field between these fields in the SEM image of the membrane cross section in the film thickness direction perpendicular to the inner surface of the hollow fiber porous membrane. SEM image obtained by photographing a predetermined field of view in the area closest to the inside of the areas of the total of 4 fields of view, 2 fields of view photographed at equal intervals. be.
In each of the above regions, there is a difference in the existence distribution of the resin portion between the membrane cross section in the membrane thickness direction perpendicular to the inner surface of the hollow fiber porous membrane and the cross section parallel to the inner surface, that is, the pores The anisotropy of connectivity can be virtually ignored.
As used herein, the term “resin portion” refers to a dendritic skeleton portion of a three-dimensional network structure made of resin, which forms a large number of pores in the porous membrane. The parts shown in black in FIG. 1 are the resin parts, and the white parts are the holes.
Inside the porous membrane, communicating pores are formed that communicate with each other while bending from the inside to the outside of the membrane. The total area of the resin part having an area of 1 μm ² or less in each of the four fields of view including the surface, the field of view including the outer surface of the film, and the two fields of view taken at equal intervals between these fields of view. However, if it is 70% or more of the total area of the resin portion, the continuity of the pores is high (that is, the existence ratio of the communicating pores inside the membrane is high), and the flux of the liquid to be treated (water permeability, water permeability), high water permeability retention rate after washing, and damage to the membrane after chemical washing, which is indexed by tensile elongation at break, is reduced. However, if the ratio of the total area of the resin part having an area of 1 μm ² or less to the total area of the resin part is too high, a tree with a three-dimensional network structure composed of resin will form a large number of pores in the porous membrane. Since the skeleton portion becomes too thin, the total area of the resin portion having an area of 1 μm ² or less is maintained at 70% or more of the total area of the resin portion, while the total area is more than 1 μm ² . It is preferable that the total area of the resin part having an area is 2% or more and 30% or less of the total area of the resin part, and the total area of the resin part having an area of 10 μm ² or more is the resin more preferably 15% or less of the total area of the resin portion, and the total area of the resin portion having an area of more than 1 μm ² and less than 10 μm ² is 15% or less of the total area of the resin portion. Further, it is more preferable that the total area of the resin portions having an area of 10 μm ² or more is 2% or more and 15% or less of the total area of the resin portions. If the total area of the resin portions having an area of more than 1 μm ² is 2% or more and 30% or less of the total area of the resin portions, a dendritic skeleton portion having a three-dimensional network structure composed of resin is formed. Since it is not too thin, the strength and tensile elongation at break of the porous membrane can be appropriately maintained.

2 to 5 are SEM images of cross sections of the porous membranes used in Example 1, Example 2, Example 3, and Comparative Example 3 in the film thickness direction orthogonal to the inner surface of the inner surface. A field including a field including the outer surface of the film, and a total of 4 fields of view (circles 1 to 4) taken at equal intervals between these fields of view. 4 is a histogram showing the ratio (%) of the total area of resin portions having an area. In FIG. 1, the resin portion appears in the form of granules. 2 to 5 show histograms of the area ratio of each area of each granular resin portion to the total area of all the resin portions in a field of view of a predetermined size in each region. showing. Circle 1 in FIGS. 2 to 5 indicates a field of view including the inner surface, a field of view including the outer surface of the membrane, and a field of view of these fields in the SEM image of the membrane cross section in the film thickness direction perpendicular to the inner surface of the porous membrane. The number of the area closest to the inside is the number of the area closest to the inside of the areas of a total of 4 fields of view of 2 fields of view photographed at equal intervals, and the circle 4 is the number of the area closest to the inside. For example, circle 1 of Example 1 is a histogram when a field of view of a predetermined size within the innermost region of the porous hollow fiber membrane of Example 1 is photographed. A method for measuring the area distribution of the resin portion in each region of the porous hollow fiber membrane will be described later.

The surface open area ratio of the porous membrane is preferably 25 to 60%, more preferably 25 to 50%, still more preferably 25 to 45%. If the surface opening ratio on the side that comes into contact with the liquid to be treated is 25% or more, clogging and deterioration of water permeability due to abrasion of the membrane surface are reduced, so filtration stability can be enhanced. On the other hand, if the surface open area ratio is high and the pore size is too large, the required separation performance may not be exhibited. Therefore, the average pore size of the porous membrane is preferably 100-700 nm, more preferably 100-600 nm. If the average pore diameter is 100 to 700 nm, the separation performance is sufficient, and pore communication can be ensured. The methods for measuring the surface open area ratio and the average pore size will be described later.

The thickness of the porous membrane is preferably 80-1,000 μm, more preferably 100-300 μm. If the film thickness is 80 μm or more, the strength of the film can be ensured.

As for the shape of the porous hollow fiber membrane, an annular single-layer membrane can be mentioned, but a multi-layer membrane having different pore diameters between the separation layer and the support layer supporting the separation layer may also be used. In addition, the membrane may have an irregular cross-sectional structure such as having projections on the inner surface and the outer surface.

(Material (material) of porous membrane)
The resin constituting the porous membrane is preferably a thermoplastic resin, more preferably a fluororesin. Examples of fluororesins include vinylidene fluoride resin (PVDF), chlorotrifluoroethylene resin, tetrafluoroethylene resin, ethylene-tetrafluoroethylene copolymer (ETFE), ethylene-monochlorotrifluoroethylene copolymer (ECTFE), hexa At least one selected from the group consisting of fluoropropylene resins and mixtures of these resins may be used.
Thermoplastic resins include polyolefins, copolymers of olefins and halogenated olefins, halogenated polyolefins, and mixtures thereof. Examples of thermoplastic resins include polyethylene (PE), polypropylene, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, ethylene-tetrafluoroethylene copolymer, polyvinylidene fluoride (which may contain hexafluoropropylene domains), these A mixture of These resins are excellent in handleability due to their thermoplasticity and toughness, and thus are excellent as membrane materials. Among these, vinylidene fluoride resin, tetrafluoroethylene resin, hexafluoropropylene resin or mixtures thereof, homopolymers or copolymers of ethylene, tetrafluoroethylene, chlorotrifluoroethylene, or mixtures of homopolymers and copolymers are mechanically It is preferable because it is excellent in strength and chemical strength (chemical resistance) and good in moldability. More specifically, fluorine resins such as polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, ethylene-tetrafluoroethylene copolymer, and ethylene-chlorotrifluoroethylene copolymer can be mentioned.

The porous membrane may contain up to about 5% by mass of components (impurities, etc.) other than the thermoplastic resin. For example, it includes a solvent used when manufacturing a porous membrane. As will be described later, the first solvent (hereinafter also referred to as a non-solvent), the second solvent (hereinafter also referred to as a good solvent or poor solvent), or both used as a solvent in the production of the porous membrane are included. . These solvents can be detected by pyrolysis GC-MS (gas chromatography-mass spectrometry).

The first solvent includes sebacate, citrate, acetylcitrate, adipate, trimellitate, oleate, palmitate, stearate, phosphate, and has 6 to 30 carbon atoms. and at least one selected from the group consisting of fatty acids and epoxidized vegetable oils.
In addition, unlike the first solvent, the second solvent contains sebacate, citrate, acetylcitrate, adipate, trimellitate, oleate, palmitate, stearate, phosphorus It may be at least one selected from the group consisting of acid esters, fatty acids having 6 to 30 carbon atoms, and epoxidized vegetable oils. Examples of fatty acids having 6 to 30 carbon atoms include capric acid, lauric acid, and oleic acid. Examples of epoxidized vegetable oils include epoxy soybean oil and epoxidized linseed oil.
The first solvent is a first mixed liquid in which the ratio of the thermoplastic resin to the first solvent is 20:80, and even if the temperature of the first mixed liquid is raised to the boiling point of the first solvent, the thermoplastic It is preferable that the resin is a non-solvent that does not uniformly dissolve in the first solvent.
The second solvent is a second mixed liquid in which the ratio of the thermoplastic resin to the second solvent is 20:80, and the temperature of the second mixed liquid is higher than 25 ° C. and the boiling point of the second solvent or lower. It is preferable that the solvent is a good solvent in which the thermoplastic resin is uniformly dissolved in the second solvent at that temperature.
The second solvent is a second mixed liquid in which the ratio of the thermoplastic resin to the second solvent is 20:80, and when the temperature of the second mixed liquid is 25 ° C., the thermoplastic resin It is a poor solvent in which the thermoplastic resin uniformly dissolves in the second solvent at any temperature where the temperature of the second mixed liquid is higher than 100 ° C. and below the boiling point of the second solvent. preferable.

In addition, in the filtration/clarification step in the method for producing fruit wine of the present embodiment, a porous hollow fiber membrane using polyvinylidene fluoride (PVDF) as a thermoplastic resin is used as the first solvent (non-solvent). can be used.
In this case, the first solvent is sebacate, citrate, acetylcitrate, adipate, trimellitate, oleate, palmitate, stearate, phosphate, and has 6 carbon atoms. At least one selected from the group consisting of 30 or less fatty acids and epoxidized vegetable oils, in a first mixed solution in which the ratio of polyvinylidene fluoride to the first solvent is 20:80, the first mixing It can be a non-solvent that does not uniformly dissolve polyvinylidene fluoride in the first solvent even when the temperature of the liquid is raised to the boiling point of the first solvent. Bis-2-ethylhexyl adipate (DOA) is preferred as the non-solvent.
Moreover, the porous hollow fiber membrane may contain a second solvent different from the first solvent. In this case, the second solvent is sebacate, citrate, acetylcitrate, adipate, trimellitate, oleate, palmitate, stearate, phosphate, and has 6 carbon atoms. At least one selected from the group consisting of 30 or less fatty acids and epoxidized vegetable oils, in a second mixture in which the ratio of polyvinylidene fluoride and the second solvent is 20:80, the second mixture It is preferable that the solvent is a good solvent that dissolves polyvinylidene fluoride uniformly in the second solvent at a liquid temperature higher than 25° C. or lower than the boiling point of the second solvent. Further, in the second solvent, polyvinylidene fluoride does not uniformly dissolve in the second solvent when the temperature of the second mixed liquid is 25 ° C., and the temperature of the second mixed liquid is higher than 100 ° C. It is more preferable that polyvinylidene fluoride is a poor solvent that uniformly dissolves in the second solvent at any temperature below the boiling point of . Acetyl tributyl citrate (ATBC) is preferred as the poor solvent.

(Physical properties of porous membrane)
The initial value of the tensile elongation at break of the porous membrane is preferably 60% or more, more preferably 80% or more, still more preferably 100% or more, and particularly preferably 120% or more. A method for measuring the tensile elongation at break will be described later.

From a practical point of view, the compressive strength of the porous membrane is preferably 0.2 MPa or more, more preferably 0.3 to 1.0 MPa, still more preferably 0.4 to 1.0 MPa.

<Method for producing porous membrane>
A method for producing a porous hollow fiber membrane will be described below. However, the method for producing the porous hollow fiber membrane used in the filtration/clarification step in the method for producing fruit wine according to the present embodiment is not limited to the following production method.
The method for producing the porous hollow fiber membrane used in the filtration/clarification step in the method for producing fruit wine according to the present embodiment includes (a) a step of preparing a melt-kneaded product, and (b) spinning the melt-kneaded product into a multi-structure. (c) a step of extracting the plasticizer from the hollow fiber membrane; When the melt-kneaded product contains an additive, the step (d) of extracting the additive from the hollow fiber membrane may be further included after the step (c).

The concentration of the thermoplastic resin in the melt-kneaded product is preferably 20 to 60% by mass, more preferably 25 to 45% by mass, still more preferably 30 to 45% by mass. If this value is 20% by mass or more, the mechanical strength can be increased, and if it is 60% by mass or less, the water permeability can be increased. The melt-kneaded product may contain additives.
The melt-kneaded product may consist of two components, a thermoplastic resin and a solvent, or may consist of three components, a thermoplastic resin, an additive, and a solvent. The solvent includes at least a non-solvent as described later.
As the extracting agent used in step (c), it is preferable to use liquids such as methylene chloride and various alcohols that do not dissolve thermoplastic resins but have high affinity with plasticizers.
When a melt-kneaded product containing no additive is used, the hollow fiber membrane obtained through step (c) may be used as the porous hollow fiber membrane. When producing a porous hollow fiber membrane using a melt-kneaded product containing an additive, after step (c), the additive (d) is extracted and removed from the hollow fiber membrane to obtain a porous hollow fiber membrane. Further steps are preferred. As the extractant in step (d), it is preferable to use hot water or a liquid that can dissolve the additives used, such as acids and alkalis, but does not dissolve the thermoplastic resin.

Inorganic substances may be used as additives. The inorganic substance is preferably inorganic fine powder. The primary particle size of the inorganic fine powder contained in the melt-kneaded product is preferably 50 nm or less, more preferably 5 nm or more and less than 30 nm. Specific examples of the inorganic fine powder include silica (including fine silica powder), titanium oxide, lithium chloride, calcium chloride, organic clay, etc. Among these, fine silica powder is preferable from the viewpoint of cost. The above-mentioned "primary particle size of inorganic fine powder" means a value obtained from analysis of electron micrographs. That is, first, a group of inorganic fine powders is pretreated by the method of ASTM D3849. After that, the diameters of 3000 to 5000 particles photographed on the transmission electron micrograph are measured, and these values are arithmetically averaged to calculate the primary particle size of the inorganic fine powder.
By identifying the elements present in the inorganic fine powder inside the porous hollow fiber membrane using fluorescent X-rays or the like, it is possible to identify the material of the inorganic fine powder present.
When an organic substance is used as an additive, a hydrophilic polymer such as polyvinylpyrrolidone or polyethylene glycol can be used to impart hydrophilicity to the hollow fiber membrane. Moreover, the viscosity of the melt-kneaded product can be controlled by using a highly viscous additive such as glycerin or ethylene glycol.

Next, the step (a) of preparing a melt-kneaded product in the method for producing a porous hollow fiber membrane of the present embodiment will be described in detail.
In the method for producing a porous hollow fiber membrane of the present embodiment, a non-solvent for a thermoplastic resin is mixed with a good solvent or poor solvent. The mixed solvent after mixing is a non-solvent for the thermoplastic resin used. When a non-solvent is used as the raw material for the membrane in this way, a porous hollow fiber membrane having a three-dimensional network structure can be obtained. Its mechanism of action is not necessarily clear, but it is thought that the crystallization of the polymer is moderately inhibited by using a solvent with a lower solubility by mixing it with a non-solvent, making it easier to form a three-dimensional network structure. . For example, non-solvents and poor or good solvents include phthalates, sebacates, citrates, acetyl citrates, adipates, trimellitates, oleates, palmitates, and stearates. , phosphate esters, fatty acids having 6 to 30 carbon atoms, various esters such as epoxidized vegetable oils, and the like.
A solvent that can dissolve a thermoplastic resin at room temperature is called a good solvent, a solvent that cannot be dissolved at room temperature but can be dissolved at high temperature is called a poor solvent for the thermoplastic resin, and a solvent that cannot be dissolved at high temperature is called a solvent. A good solvent, a poor solvent, and a non-solvent can be determined as follows.
Put about 2g of thermoplastic resin and about 8g of solvent in a test tube, heat up to the boiling point of the solvent in about 10°C increments with a test tube block heater, mix the inside of the test tube with a spatula, etc., and the thermoplastic resin A solvent that dissolves is a good solvent or a poor solvent, and a solvent that does not dissolve is a non-solvent. A substance that dissolves at a relatively low temperature of 100° C. or less is judged as a good solvent, and a substance that does not dissolve unless the temperature is raised to a temperature of 100° C. or above and below the boiling point is judged as a poor solvent.
For example, when polyvinylidene fluoride (PVDF) is used as the thermoplastic resin and acetyl tributyl citrate (ATBC), dibutyl sebacate, or dibutyl adipate is used as the solvent, PVDF is uniformly mixed with these solvents at about 200°C. Dissolve. On the other hand, when bis-2-ethylhexyl adipate (DOA), diisononyl adipate, or bis-2-ethylhexyl sebacate is used as the solvent, PVDF does not dissolve in these solvents even when the temperature is raised to 250°C.
When ethylene-tetrafluoroethylene copolymer (ETFE) is used as the thermoplastic resin and diethyl adipate is used as the solvent, the ETFE is uniformly mixed and dissolved at about 200.degree. On the other hand, it does not dissolve when bis-2-ethylhexyl adipate (DIBA) is used as a solvent.
Also, when ethylene-monochlorotrifluoroethylene copolymer (ECTFE) is used as the thermoplastic resin and triethyl citrate is used as the solvent, it dissolves uniformly at about 200°C, and when triphenylphosphite (TPP) is used, it dissolves. do not.

EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these. Each physical property value in Examples and Comparative Examples was obtained by the following methods.

(1) Outer Diameter and Inner Diameter of Porous Hollow Fiber Membrane The porous hollow fiber membrane was thinly sliced using a razor in a cross section orthogonal to the length direction, and the outer diameter and inner diameter were measured with a 100x magnifying glass. . For one sample, measurements were taken at 60 cut surfaces at intervals of 30 mm for the length method, and the average value was taken as the outer diameter and inner diameter of the hollow fiber membrane.

(2) Electron microscopic photography A porous hollow fiber membrane was cut into an annular shape in a cross section perpendicular to the length direction, dyed with 10% phosphotungstic acid + osmium tetroxide, and embedded in an epoxy resin. Then, after trimming, the cross section of the sample was subjected to BIB processing to prepare a smooth cross section, which was then subjected to a conductive treatment to prepare a microscopic sample. Using the HITACHI SU8000 series electron microscope, the electron microscope (SEM) image of the cross section of the film at an acceleration voltage of 1 kV is 5,000 to 30,000 times the film thickness (thick part) cross section. A field of view including the inner surface of the membrane, a field of view including the outer surface of the membrane, and two fields of view taken at equal intervals between these fields of view, a total of 4 fields of view (circles 1 to 4 in Figures 2 to 5) was taken at a predetermined field of view. It can be measured by changing the magnification according to the average pore diameter. Specifically, when the average pore diameter is 0.1 μm or more, it is 5000 times. , 10,000 times, and 30,000 times when the average pore size is less than 0.05 μm. The size of the field of view was 2560×1920 pixels.
ImageJ was used for image processing, and the captured SEM image was subjected to threshold processing (Image-Adjust-Threshold: Otsu method (Otsu was selected)) to binarize the hole portion and the resin portion. .
Surface aperture ratio: The surface aperture ratio was measured by calculating the ratio of the resin portion and the hole portion in the binarized image.
Area distribution of resin part: Using ImageJ's "Analyze Particle" command (Analyz Particle: Size 0.10-Infinity), the size of the binarized granular resin part contained in the captured SEM image was measured. . If the total area of all the resin parts included in the SEM image is ΣS, and the area of the resin parts of 1 μm ² or less is ΣS (<1 μm ^{2 ), then ΣS (<1 μm 2 )} /ΣS is calculated to obtain 1 μm The area ratio of the resin portion having an area of ² or less was calculated. Similarly, the area ratio of the resin portion having an area within a predetermined range was calculated.
Regarding the noise removal when performing the binarization process, the resin portion with an area of less than 0.1 μm ² was removed as noise, and the resin portion with an area of 0.1 μm ² or more was analyzed. Further, noise was removed by applying median filter processing (Process-Filters-Median: Radius: 3.0 pixels).
In addition, a granular resin part cut off at the edge of the SEM image was also measured. Also, the "Include Holes" treatment was not performed. In addition, no processing was performed to correct the shape from a "snowman" shape to a "flat" shape or the like.
Mean Pore Pore Size: Measured using ImageJ's "Plugins-Bone J-Thickness" command. The space size was defined as the maximum circle size that fits into the gap.

(3) Flux (permeability, initial pure water flux)
After immersing the porous hollow fiber membrane in ethanol and repeating immersion in pure water several times, one end of the wet hollow fiber membrane having a length of about 10 cm was sealed, and an injection needle was inserted into the hollow part of the other end. 25 ° C. pure water is injected from the injection needle at a pressure of 0.1 MPa in an environment of ° C., the amount of pure water permeating from the outer surface of the membrane is measured, and the following formula:
Initial pure water flux [L/m ² /h] = 60 × (permeated water amount [L]) / {π × (membrane outer diameter [m]) × (membrane effective length [m]) × (measurement time [min] )}
The pure water flux was determined by , and the water permeability was evaluated.
The term "effective membrane length" refers to the net membrane length excluding the portion where the injection needle is inserted.

(4) Permeability retention rate during actual liquid filtration Next, (i) put pure water into the circulation tank, perform circulation filtration so that the transmembrane pressure difference = 0.05 MPa, and collect the permeated water for 1 minute. It was taken as the initial water permeability.
Next, (ii) after removing the water in the pipe, the fruit liquor undiluted solution was put into the circulation tank and circulated and filtered so that the transmembrane pressure difference was 0.15 MPa.
Next, (iii) after removing the residual liquid in the pipe, pure water was put into the circulation tank, and the product was circulated and filtered so that the transmembrane pressure difference was 0.05 MPa, and washed with water.
Next, (iv) after removing the water in the pipe, the prepared chemical solution was put into the circulation vessel, and membrane circulation filtration was carried out to carry out cleaning with the chemical solution for 30 minutes. An aqueous solution obtained by mixing 0.2% by weight of sodium hypochlorite and 1% by weight of caustic soda was used as the chemical solution.
Next, (v) after cleaning with the chemical solution, remove the chemical solution from the piping, put pure water into the circulation tank, perform circulation filtration so that the transmembrane pressure difference = 0.05 MPa, and remove the permeated water that comes out. Samples were repeatedly collected at a timing of 10 L/m ² , and when the permeate had a chlorine concentration of 0.1 ppm or less and a pH of 8.6 or less, washing was terminated, and the amount of water used for rinsing was recorded. Further, circulating filtration was continued at the same transmembrane pressure difference, and the permeated water was sampled for 1 minute and used as the permeation amount.
Each parameter was calculated by the following formula:
Transmembrane pressure difference = {(input pressure) + (output pressure)}/2
Inner membrane surface area [m ² ] = π x (hollow fiber membrane inner diameter [m]) x (hollow fiber membrane effective length [m])
Membrane surface linear velocity [m/s]=4×(circulating water volume [m ³ /s])/{π×(membrane inner diameter [m]) ² }. All operations were performed at 25° C. and a film surface linear velocity of 1.0 m/sec.

(5) Tensile elongation at break (%)
A porous hollow fiber membrane was used as a sample, and the tensile elongation at break was calculated according to JIS K7161. The load and displacement at tensile breakage were measured under the following conditions.
Measuring equipment: Instron type tensile tester (AGS-5D manufactured by Shimadzu Corporation)
Distance between chucks: 5cm
Pulling speed: 20cm/min

(6) Absorbance UVmini-1240 manufactured by SHIMADZU was used to measure absorbance. The scanning range was set from 250 nm to 700 nm, and the fruit liquor before and after filtration was placed in a quartz cell and measured. The optical path length was appropriately selected from two types, 1 cm and 5 cm, depending on the type of fruit liquor and the dilution factor. The liquid temperature was measured at 20°C. Before the measurement of the fruit liquor before and after filtration, the background measurement was performed with pure water in advance, and then the cell was washed with the sample solution three times before the measurement was performed. After measurement, the color tone and color intensity of each sample solution were calculated from the absorbance at 420 nm, 520 nm, and 620 nm. The color tone referred to here is a value of (absorbance at 420 nm)/(absorbance at 520 nm), and is used as an index of vividness of fruit wine. Further, the color intensity is a value of (absorbance at 420 nm) + (absorbance at 520 nm) + (absorbance at 620 nm), and was used as an index indicating the depth of color of fruit wine.

(7) pH
HORIBA's pH METER F-22 was used to measure the pH of the fruit liquor. After calibrating with standard solutions of pH = 4.01, 6.86, and 9.18 before measurement, the pH of the fruit liquid was measured before and after filtration at a liquid temperature of 20°C.

(8) Sugar content A pocket sugar content meter PAL-S manufactured by ATAGO was used to measure the sugar content of the fruit wine. 0.5 mL of the sample liquid was dropped onto the stage, and the sugar content of the sample liquid at a liquid temperature of 20°C was measured.

(9) Turbidity A 2100P TURBIDIMETER manufactured by HACH was used to measure the turbidity of the fruit liquor. 15 mL of the sample liquid was placed in a glass cell, and the turbidity of the sample liquid at a liquid temperature of 20°C was measured.

(10) Viscosity A VISCOMATE viscometer MODEL VM-1G manufactured by Yamaichi Denki Co., Ltd. was used to measure the viscosity of the fruit liquor. 30 mL of the sample liquid was placed in a 50 mL container glass beaker, and the viscosity of the sample liquid at a liquid temperature of 20°C was measured.

(11) Haze
Haze Meter NDH4000 manufactured by Nippon Denshoku Industries Co., Ltd. was used to measure the haze of the fruit liquor. 20 mL of the sample liquid was placed in a glass cell, and the cloudiness of the sample liquid at a liquid temperature of 20°C was measured.

(12) Alkali resistance test After the actual liquid filtration described in (4) above, the porous hollow fiber membrane was cut into 10 cm pieces, 20 pieces were immersed in 500 ml of a 4% sodium hydroxide aqueous solution, and held at 40 ° C. for 10 days. bottom. The tensile elongation at break of the film before and after immersion in sodium hydroxide was measured with n20, and the average value was calculated. The elongation retention rate after NaOH immersion is calculated by the following formula:
Elongation retention after immersion in NaOH = (tensile elongation at break after immersion)/(tensile elongation at break before immersion) x 100
and evaluated the alkali resistance. The tensile elongation at break before immersion corresponds to the tensile elongation at break before the washing process, and the tensile elongation at break after immersion corresponds to the tensile elongation at break after the washing process.
Further, after the above-described real liquid filtration, the above-described washing step by immersion in a 4% sodium hydroxide aqueous solution was repeated 10 times. Then, the initial value of the tensile breaking elongation (tensile breaking elongation before immersion) is E0, and the value of the tensile breaking strength of the porous hollow fiber membrane after repeating the washing process 10 times is EX, where EX/E0× Alkali resistance was evaluated by calculating 100 as "elongation retention rate after 10 cycles of repeated washing".
Further, after the above-mentioned real liquid filtration, the hollow fiber membrane was immersed in a 4% sodium hydroxide aqueous solution and kept at 40° C. for 10 days. After immersion in sodium hydroxide, filtration is performed for 10 minutes at the same filtration pressure as when measuring the initial pure water permeation rate described above, and the permeated water is collected for 2 minutes from the 8th minute to the 10th minute of filtration, and the washing process. Post-permeability. The initial pure water permeation amount was defined as LO (flux L0), the water permeation amount after the washing process was defined as L1 (flux L1), and L1/L0×100 was calculated as the water permeation amount retention rate after NaOH immersion.
Further, after the above-described real liquid filtration, the above-described washing step of immersing the hollow fiber membrane in a 4% sodium hydroxide aqueous solution was repeated 10 times. Then, filtration is performed for 10 minutes at the same filtration pressure as when the initial pure water permeability was measured, and the permeated water was collected for 2 minutes from the 8th minute to the 10th minute of filtration, and the water permeability after the repeated washing process. bottom. The initial pure water permeation rate is LO (flux L0), the water permeation rate after repeated washing is LX (flux LX, X = 10), and LX/L0 x 100 is calculated as "permeability retention rate after 10 cycles of repeated washing". bottom.

[Example 1]
40% by mass of PVDF resin (Kureha Co., Ltd., KF-W #1000) as a thermoplastic resin, 23% by mass of finely divided silica (primary particle size: 16 nm), and 20% by mass of bis-2-ethylhexyl adipate (DOA) as a non-solvent.7. A melt-kneaded product was prepared using 7% by mass and 9.3% by mass of acetyl tributyl citrate (ATBC, boiling point 343° C.) as a poor solvent. The temperature of the resulting molten mixture was 240°C. The resulting melt-mixed material is passed through a spinning nozzle having a double-tube structure, and the hollow fiber-like extrudate is passed through a free running distance of 120 mm. developed. The obtained hollow fiber extrudate was taken up at a speed of 5 m/min and wound on a skein. The wound hollow fiber extrudate is immersed in isopropyl alcohol to extract and remove DOA and ATBC, then immersed in water for 30 minutes to replace the hollow fiber membrane with water, and then soaked in a 20 wt% NaOH aqueous solution for 70 minutes. C. for 1 hour, and then repeatedly washed with water to extract and remove finely divided silica to prepare a porous hollow fiber membrane.
Table 1 below shows the composition, manufacturing conditions, and various physical properties of the obtained porous membrane. The resulting porous hollow fiber membrane had a three-dimensional network structure. In addition, the membrane had a high flux (water permeability) and a high degree of communication.

A filtration/clarification step was carried out using the obtained hollow fiber membrane. Tokiyama Sauvignon red wine (Akita Winery) was used as the treatment liquid. A filtration experiment system was constructed using the following instruments. Masterflex (registered trademark, model number 7523-60) manufactured by Cole Palmer Co., Ltd. was used as a liquid-sending pump. For the pump head, Masterflex (registered trademark) Easy Load (model number 7518-10) also manufactured by Cole Palmer was used. As liquid feeding tubes, Pharmed (registered trademark) BPT pump tube (model number 06508-25) and Masterflex (registered trademark) silicon tube (model number 96400-16) were used. A module with an effective membrane area of 120 cm ² and a total length of 130 mm was produced and subjected to filtration evaluation.
After connecting the pump tube so that the bottom of the module is the supply side, the top is the circulation side, and the top side nozzle is the filtration side so that the stock solution can be introduced to the inner surface of the hollow fiber membrane, 100 mL of the stock solution is placed in an ice bath. The inside of the module was co-washed by circulating liquid at a speed of 600 L/min by a liquid-sending pump. After co-washing for 10 minutes, all the circulating liquid was discharged. After that, 2000 mL of the undiluted solution was cooled to 20° C. or lower in an ice-cooling bath, and the solution was sent at a rate of 600 L/min by a liquid sending pump. The filtration valve was opened so that the output pressure on the circulation side was 55 kPa, and cross-flow filtration was performed for 20 minutes. At that time, the filtrate was transferred to the stock solution tank and the mixing was continued. After that, the filtration valve was opened so that the output pressure on the circulation side was 55 kPa, and cross-flow filtration was performed for 20 minutes. A total of 1900 mL of filtrate was collected with a graduated cylinder. After filtration, the absorbance, pH, sugar content, turbidity, viscosity, and haze of the undiluted solution and filtrate were measured and evaluated.
When the absorbance of red wine before and after the filtration process was measured, the ratio of absorbance before and after filtration was 0.98 at 420 nm, 0.98 at 520 nm, and 0.95 at 620 nm, as shown in Table 2 below. Also, the ratio of color intensity before and after filtration was 0.99.
In addition, the water permeability retention rate at the time of real liquid filtration was 75%, the elongation retention rate after NaOH immersion was 80%, and the water permeability retention rate after NaOH immersion was 99%. The degree retention was 70%, and the water permeability retention after 10 cycles of repeated washing was 95%.
In addition, in the above (4) measurement of the water permeability retention rate during real liquid filtration, when the chlorine concentration of the permeated water became 0.1 ppm or less and the pH became 8.6 or less, the rinse was completed. was 40 (L/m ² ).

[Example 2]
40% by mass of ETFE resin (TL-081, manufactured by Asahi Glass Co., Ltd.) as a thermoplastic resin, 23% by mass of finely divided silica (primary particle size: 16 nm), and 18.5% by mass of bis-2-ethylhexyl adipate (DOA) as a non-solvent. % and 18.5% by mass of diisobutyl adipate (DIBA) as a poor solvent to prepare a melt-kneaded product. The temperature of the resulting molten mixture was 240°C. The resulting melt-mixed material is passed through a spinning nozzle having a double-tube structure, and the hollow fiber-like extrudate is passed through a free running distance of 120 mm. developed. The obtained hollow fiber extrudate was taken up at a speed of 5 m/min and wound on a skein. The wound hollow fiber extrudate is immersed in isopropyl alcohol to extract and remove DOA and DIBA, then immersed in water for 30 minutes to replace the hollow fiber membrane with water, and then soaked in a 20 wt% NaOH aqueous solution for 70 minutes. C. for 1 hour, and then repeatedly washed with water to extract and remove finely divided silica to prepare a porous hollow fiber membrane.
Table 1 below shows the composition, manufacturing conditions, and various physical properties of the obtained porous membrane. The resulting porous hollow fiber membrane had a three-dimensional network structure. In addition, the membrane had a high flux (water permeability) and a high degree of communication.
A filtration step was performed using the obtained hollow fiber membrane. As in Example 1, Tokiyama Sauvignon red wine was used as the treatment liquid. The filtration experiment method was carried out with the same specifications as in Example 1. When the absorbance of red wine before and after the filtration process was measured, the ratio of absorbance before and after filtration was 0.98 at 420 nm, 0.98 at 520 nm, and 0.97 at 620 nm, as shown in Table 2 below. The color intensity ratio before and after filtration was 1.00.
In addition, the water permeability retention rate at the time of real liquid filtration was 70%, the elongation retention rate after NaOH immersion was 98%, and the water permeability retention rate after NaOH immersion was 100%. The water retention rate was 90%, and the water permeability retention rate after 10 cycles of repeated washing was 96%.
In addition, in the above (4) measurement of the water permeability retention rate during real liquid filtration, when the chlorine concentration of the permeated water became 0.1 ppm or less and the pH became 8.6 or less, the rinse was completed. was 35 (L/m ² ).

[Example 3]
40% by mass of ECTFE resin (Halar 901, manufactured by Solvay Specialty Polymers) as a thermoplastic resin, 23% by mass of finely divided silica (primary particle size: 16 nm), and 29% by mass of triphenyl phosphite (TPP) as a non-solvent. A melt-kneaded product was prepared using 0.6% by mass and 7.4% by mass of bis-2-ethylhexyl adipate (DOA) as a poor solvent. The temperature of the resulting molten mixture was 240°C. The resulting melt-mixed material is passed through a spinning nozzle having a double-tube structure, and the hollow fiber-like extrudate is passed through a free running distance of 120 mm. developed. The obtained hollow fiber extrudate was taken up at a speed of 5 m/min and wound on a skein. The wound hollow fiber extrudate is immersed in isopropyl alcohol to extract and remove TPP and DOA, then immersed in water for 30 minutes to replace the hollow fiber membrane with water, and then soaked in a 20 wt% NaOH aqueous solution for 70 minutes. C. for 1 hour, and then repeatedly washed with water to extract and remove finely divided silica to prepare a porous hollow fiber membrane.
Table 1 below shows the composition, manufacturing conditions, and various physical properties of the obtained porous membrane. The resulting porous hollow fiber membrane had a three-dimensional network structure. In addition, the membrane had a high flux (water permeability) and a high degree of communication.
A filtration step was performed using the obtained hollow fiber membrane. As in Example 1, unfiltered red wine of Tokiyama Sauvignon (Akita Winery) was used as the treatment liquid. The filtration experiment method was carried out with the same specifications as in Example 1. When the absorbance of red wine before and after the filtration process was measured, the ratio of absorbance before and after filtration was 0.99 at 420 nm, 0.98 at 520 nm, and 0.98 at 620 nm, as shown in Table 2 below. Also, the ratio of color intensity before and after filtration was 0.99.
In addition, the water permeability retention rate at the time of real liquid filtration was 80%, the elongation retention rate after NaOH immersion was 97%, and the water permeability retention rate after NaOH immersion was 98%. The degree retention was 95%, and the water permeability retention after 10 cycles of repeated washing was 95%.
In addition, in the above (4) measurement of the water permeability retention rate during real liquid filtration, when the chlorine concentration of the permeated water became 0.1 ppm or less and the pH became 8.6 or less, the rinse was completed. was 50 (L/m ² ).

[Comparative Example 1]
The wine after the fermentation process was mixed with diatomaceous earth of Standard Supercell (manufactured by Celite), and filtered with a filter press manufactured by Naigai Johki Co., Ltd. at a pressure of 1.0 MPa. As in Example 1, Tokiyama Sauvignon red wine was used as the treatment liquid. When the absorbance of red wine before and after the filtration process was measured, the ratio of absorbance before and after filtration was 0.68 at 420 nm, 0.67 at 520 nm, and 0.64 at 620 nm, as shown in Table 2 below. Also, the ratio of color intensity before and after filtration was 0.67.

[Comparative Example 2]
A hollow fiber membrane of Comparative Example 2 was obtained by forming the membrane in the same manner as in Example 1 except that only ATBC was used as the solvent. Table 1 below shows the composition, manufacturing conditions, and various physical properties of the obtained porous membrane. The resulting porous hollow fiber membrane had a spherulite structure. In addition, the flux was low and the membrane had low connectivity.
A filtration step was performed using the obtained hollow fiber membrane. As in Example 1, Tokiyama Sauvignon red wine was used as the treatment liquid. The filtration experiment method was carried out with the same specifications as in Example 1. When the absorbance of red wine before and after the filtration process was measured, the ratio of absorbance before and after filtration was 0.70 at 420 nm, 0.70 at 520 nm, and 0.69 at 620 nm, as shown in Table 2 below. Moreover, the ratio of color intensity before and after filtration was 0.7.
In addition, the water permeability retention rate at the time of real liquid filtration was 30%, the elongation retention rate after NaOH immersion was 30%, and the water permeability retention rate after NaOH immersion was 150%. The degree retention was 20%, and the water permeability retention after 10 cycles of repeated washing was 200%.
In addition, in the above (4) measurement of the water permeability retention rate during real liquid filtration, when the chlorine concentration of the permeated water became 0.1 ppm or less and the pH became 8.6 or less, the rinse was completed. was 140 (L/m ² ).

[Comparative Example 3]
A hollow fiber membrane of Comparative Example 3 was obtained by forming the membrane in the same manner as in Example 1 except that the finely divided silica was 0% and the solvent was only γ-butyrolactone. Table 1 below shows the composition, manufacturing conditions, and various physical properties of the obtained porous membrane. The resulting porous hollow fiber membrane had a spherulite structure. In addition, the flux was low and the membrane had low connectivity.
A filtration step was performed using the obtained hollow fiber membrane. As in Example 1, Tokiyama Sauvignon red wine was used as the treatment liquid. The filtration experiment method was carried out with the same specifications as in Example 1. When the absorbance of red wine before and after the filtration process was measured, the ratio of absorbance before and after filtration was 0.68 at 420 nm, 0.68 at 520 nm, and 0.67 at 620 nm, as shown in Table 2 below. Moreover, the ratio of color intensity before and after filtration was 0.68. In addition, the water permeability retention rate during real liquid filtration was 30%, the elongation retention rate after NaOH immersion was 30%, and the water permeability retention rate after NaOH immersion was 160%. The degree retention was 20%, and the water permeability retention after 10 cycles of repeated washing was 180%.
In addition, in the above (4) measurement of the water permeability retention rate during real liquid filtration, when the chlorine concentration of the permeated water became 0.1 ppm or less and the pH became 8.6 or less, the rinse was completed. was 150 (L/m ² ).

[Comparative Example 4]
A hollow fiber membrane of Comparative Example 4 was obtained by forming the membrane in the same manner as in Example 3 except that DOA was used as the solvent. Table 1 below shows the composition, manufacturing conditions, and various physical properties of the obtained porous membrane. The resulting porous hollow fiber membrane had a spherulite structure. In addition, the flux was low and the membrane had low connectivity.
A filtration step was performed using the obtained hollow fiber membrane. As in Example 1, Tokiyama Sauvignon red wine was used as the treatment liquid. The filtration experiment method was carried out with the same specifications as in Example 1. When the absorbance of red wine before and after the filtration process was measured, the ratio of absorbance before and after filtration was 0.61 at 420 nm, 0.60 at 520 nm, and 0.57 at 620 nm, as shown in Table 2 below. Moreover, the ratio of color intensity before and after filtration was 0.6.

[Example 4]
The hollow fiber membrane was formed under the same conditions as in Example 1. Table 3 below shows the composition, manufacturing conditions, and various physical properties of the resulting porous membrane. Red wine immediately after fermenting concentrated fruit juice, which is a blend of multiple types, was used as the undiluted solution. The filtration experiment method was carried out with the same specifications as in Example 1. Various analysis results before and after the filtration process are shown in Table 4 below.

[Comparative Example 5]
As the filtration method, diatomaceous earth filtration was selected as in Comparative Example 1. The same stock solution as in Example 4 was used as the treatment solution. The filtration experiment method was carried out with the same specifications as in Example 1. Various analysis results before and after the filtration process are shown in Table 2 below.

[Example 5]
The hollow fiber membrane was formed under the same conditions as in Example 1. Table 3 below shows the composition, manufacturing conditions, and various physical properties of the resulting porous membrane. The unfiltered white wine of Riesling Forte (Asahimachi Wine) was used as the undiluted solution for the treatment liquid. The filtration experiment method was carried out with the same specifications as in Example 1. Various analysis results before and after the filtration process are shown in Table 4 below.

[Comparative Example 6]
As the filtration method, diatomaceous earth filtration was selected as in Comparative Example 1. The same stock solution as in Example 5 was used as the treatment solution. The filtration experiment method was carried out with the same specifications as in Example 1. Various analysis results before and after the filtration process are shown in Table 4 below.

[Example 6]
The hollow fiber membrane was formed under the same conditions as in Example 1. Table 3 below shows the composition, manufacturing conditions, and various physical properties of the resulting porous membrane. Unfiltered cider made from Aomori apples (Hirosaki Cider Kobo) was used as the undiluted solution for the treatment liquid. The filtration experiment method was carried out with the same specifications as in Example 1. Various analysis results before and after the filtration process are shown in Table 4 below.

[Comparative Example 7]
As the filtration method, diatomaceous earth filtration was selected as in Comparative Example 1. The same stock solution as in Example 6 was used as the treatment solution. The filtration experiment method was carried out with the same specifications as in Example 1. Various analysis results before and after the filtration process are shown in Table 4 below.

[Example 7]
The hollow fiber membrane was formed under the same conditions as in Example 1. Table 3 below shows the composition, manufacturing conditions, and various physical properties of the resulting porous membrane. Anzuroshu (Kirin Beverage Co., Ltd.) was used as the undiluted solution for the treatment liquid. The filtration experiment method was carried out with the same specifications as in Example 1. Various analysis results before and after the filtration process are shown in Table 4 below.

[Comparative Example 8]
As the filtration method, diatomaceous earth filtration was selected as in Comparative Example 1. The same stock solution as in Example 7 was used as the treatment solution. The filtration experiment method was carried out with the same specifications as in Example 1. Various analysis results before and after the filtration process are shown in Table 4 below.

From the above results, it was found that membranes with good communication properties are excellent in filtration performance, permeability of chromaticity components, resistance to chemical solutions, and have a long life.

In the filtration/clarification step in the method for producing fruit wine according to the present invention, the pores of the porous filtration membrane (from the inside of the membrane on the side of the liquid to be treated to the outside of the membrane on the side of the filtrate) have good communication. Since a high-quality membrane is used, the color of the fruit liquor before and after filtration is small, and the sediment removal rate is high. / Or even when using an aqueous solution containing 0.05% by weight or more and 0.5% by weight or less of sodium hypochlorite or 0.4% by weight or more and 4% by weight or less of sodium hydroxide, the membrane Since deterioration can be minimized, the method for producing fruit wine according to the present invention is excellent in filtration performance and resistance to chemical solutions, and has a long life.

Claims (17)

The following steps:
A fermentation step of fermenting fruit to obtain a fruit wine containing aggregates of sediment components; a filtration/clarification step of separating the filtrate from the aggregates of the sediment components;
A method for producing a fruit wine comprising
In the SEM image of the membrane cross section in the film thickness direction perpendicular to the inner surface of the porous membrane, a field of view including the inner surface, a field of view including the outer surface of the membrane, and a field of view including the outer surface of the membrane, and photographed at equal intervals between these fields 2 In each region of a total of 4 fields of view, the total area of the resin portion having an area of 0.1 μm ² or more and 1 μm ² or less is 70% or more of the total area of the resin portion and is more than 1 μm ² is 2% or more and 30% or less of the total area of the resin portion, and the total area of the resin portion having an area of 10 μm2 ^or more is the resin portion 15% or less of the total area of and X1 the absorbance of the fruit wine before the filtration / clarification process at an arbitrary wavelength of 250 nm to 650 nm, and the absorbance of the fruit wine after the filtration / clarification process when X2 satisfies the relationship X2/X1≧0.75,
A method for producing a fruit liquor characterized by: 2. The method according to claim 1, wherein in said filtration/clarification step, a mixture of fruit wine obtained in the fermentation step and bentonite is passed through a porous membrane composed of a resin having a three-dimensional network structure. 3. The method according to claim 1, wherein the porous membrane has a surface open area ratio of 25 to 60%. The method according to any one of claims 1 to 3, wherein said porous membrane is a hollow fiber membrane. The method according to any one of claims 1 to 4, wherein the resin constituting the porous membrane is a thermoplastic resin. 6. The method according to claim 5, wherein the thermoplastic resin is a fluororesin. The fluororesin includes vinylidene fluoride resin (PVDF), chlorotrifluoroethylene resin, tetrafluoroethylene resin, ethylene-tetrafluoroethylene copolymer (ETFE), ethylene-monochlorotrifluoroethylene copolymer (ECTFE), hexa 7. The method of claim 6, wherein the resin is any one selected from the group consisting of fluoropropylene resins and mixtures of these resins. 6. The method of claim 5, wherein the thermoplastic resin is polyethylene (PE). After the filtering/clarification step, the method further comprises a washing step of washing the inside of the porous membrane by passing or immersing the washing liquid through the porous membrane, wherein the washing liquid is hot water of 50°C to 90°C. The method according to any one of claims 1-8. After the filtration/clarification step, the porous membrane further comprises a washing step of passing or immersing a washing liquid through the porous membrane to wash the inside of the porous membrane, wherein the washing liquid is 0.05% by weight or more and 0.5% by weight. % or less of sodium hypochlorite or 0.4 wt % or more and 4 wt % or less of sodium hydroxide. The relationship between the tensile elongation at break E0 of the porous membrane before the washing step and the tensile elongation at break E1 of the porous membrane after the washing step is E1/E0×100≧80%. 11. The method according to 9 or 10. The tensile breaking elongation E0 of the porous membrane before the washing step and the tensile breaking elongation of the porous membrane after repeating the washing step X times (where X is an integer of 2 to 100) 11. The method according to claim 9 or 10, wherein the relationship with degree EX is EX/E0*100≧70%. 11. The relationship between the flux L0 of the porous membrane before the filtration/clarification step and the flux L1 of the porous membrane after the washing step is L1/L0×100≧95%. The method described in . The flux L0 of the porous membrane before the filtration/clarification step, and the flux LX of the porous membrane after repeating the washing step X times (where X is an integer of 2 to 100). 11. The method according to claim 9 or 10, wherein the relationship X/L0×100≧90%. 15. The cleaning step according to any one of claims 9 to 14, wherein the cleaning step includes a cleaning liquid step of performing cleaning with the cleaning liquid, and then a rinsing step of performing rinsing with rinse water for removing remaining cleaning liquid components. the method of. The method according to claim 15, wherein the amount of rinsing water used in the rinsing step is 100 L/ ^m2 or less per unit area of the porous membrane. 17. The method according to claim 15 or 16, wherein the filtrate after restarting the filtration/clarification step after the rinsing step has a chlorine concentration of 0.1 ppm or less and a pH of the filtrate of 8.6 or less. described method.

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