JP4637641B2 - Low salt food production method and low salt food production system - Google Patents

Description

  The present invention relates to a low salt food production method and a low salt food production system. More specifically, the present invention relates to a method for surely and easily obtaining a good quality low-salt food having a good flavor by sufficiently reducing the salt content in the food at low energy and low cost, and a simple production system used therefor.

  Salinity is indispensable for life and is not only necessary for maintaining and adjusting physiological functions in the body, but also plays an important role in taste. However, high salt intake is considered to be one of the causes of adult diseases such as hypertension and stroke, and the salt content has been reduced compared to conventional cases when dietary treatment that already refrains from salt is required. Development of various low-salt foods that have been made is underway.

  Among various foods that should be low salified, seasonings such as soy sauce and miso are frequently used, and various low salinization methods have been proposed.

  For example, after separating soy sauce into a permeate and a concentrate with a reverse osmosis membrane, the permeate is desalted by electrodialysis using an ion exchange membrane, and the concentrated solution is mixed with the obtained desalted water. A method for producing reduced salt soy sauce has been proposed (see Patent Document 1). Usually, only the treatment by the electrodialysis method loses the nitrogen component in the soy sauce, and the flavor of the soy sauce is impaired. Thus, the deterioration of the flavor is suppressed by mixing the concentrated solution with the demineralized water.

  However, in the production method described above, the separation by the reverse osmosis membrane and the electrodialysis treatment by the ion exchange membrane must be performed by setting each condition, and the operation is complicated and takes time. In addition, when processing with a reverse osmosis membrane, the operating pressure of the filtration device has to be set to a very high value of 3 MPa or more, and in addition to the need for a dedicated expensive high-pressure pump, the power cost of such a high-pressure pump High maintenance costs are also required. In addition, there is a problem that the electric cost of applying a direct current during electrodialysis is high, and a very high maintenance cost is required.

  In addition to the above, the soy sauce is processed in an electrodialysis apparatus composed of parts in which a cation exchange membrane, a bipolar membrane and an anion exchange membrane are arranged in order, and parts in which a cation exchange membrane and an anion exchange membrane are arranged in order. A method for producing reduced salt soy sauce has been proposed (see Patent Document 2). Thus, by using a bipolar membrane, the change of the amino acid composition which is a nitrogen component in soy sauce is suppressed, and a flavor is hard to fall.

However, when using the bipolar membrane, a relatively large amount of pure water is required, and in addition to the normal cation exchange membrane and anion exchange membrane, such a bipolar membrane must be newly arranged in the apparatus. . In addition, the cost of electricity for operating the electrodialyzer is high, and the arrangement of the bipolar membrane requires about three times the normal amount of electricity, such as 6 A / dm ^2, which requires a very high maintenance cost. There is.
Japanese Patent Laid-Open No. 4-271864 JP-A-7-313098

  The present invention has been made in view of the above-described background art, and is intended to reliably and easily obtain a good-quality low-salt food having a good flavor by sufficiently reducing the salt content in the food at low energy and low cost. It is an object to provide a method and a simple manufacturing system used therefor.

That is, the present invention
(1) A method for producing a low-salt food wherein at least dialysis treatment is performed on the food,
The dialysis treatment is performed with a mosaic charged membrane ,
The mosaic charged membrane has a granular cation exchange resin and a granular anion exchange resin randomly distributed;
The cation-exchange resin and the anion exchange resin, both having an average method for producing low-salt food particle size Ru 500μm or less of the ion exchange resin der least 20 [mu] m, and (2) at least dialysis treatment facility low salt A food production system,
The present invention relates to a low-salt food production system used for the production method, wherein the dialysis treatment facility is provided with a mosaic charged membrane.

  According to the production method of the present invention and the low-salt food production system used therefor, the salt content in the food is sufficiently reduced at low energy and low cost, and a high-quality low-salt food that maintains its original good flavor is ensured and reliably. Can be easily obtained. At the same time, the food can be lightened.

The method for producing a low-salt food of the present invention is characterized in that at least a dialysis treatment is performed on the food, and the dialysis treatment is performed with a mosaic charged membrane. “Food products” subject to the present invention include, for example, seasonings such as soy sauce, miso, sauce, butter, soup stock, consomme, tomato sauce, tomato ketchup, soup, rice vinegar; juice, soups, pickles, plum dried Such as that which can be required to reduce its salt content. However, since the dialysis treatment using the mosaic charged membrane is performed in the production method and the production system of the present invention, the liquid food that has the fluidity and is not too viscous and can be treated by the mosaic charged membrane is targeted. . The “low-salt food” is a product in which the salt content in the “food” is reduced, that is, the contents of Na ⁺ and Cl ⁻ as salt components are reduced.

  Embodiments of a method for producing a low-salt food of the present invention and a low-salt food production system used therefor will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic configuration diagram illustrating an example of a low salt food production method and a low salt food production system used in the low salt food production method according to the first embodiment of the present invention, where soy sauce is used as a representative example of the target food. FIG. As shown in FIG. 1, the low salt soy sauce production system as an example of the present embodiment includes at least a dialysis treatment facility 1, and the dialysis treatment facility 1 includes a mosaic charged membrane 10. Hereinafter, when the food is soy sauce, that is, a method for producing low salt soy sauce and a low salt soy sauce producing system will be specifically described, the food subject to this embodiment is not limited to such soy sauce. .

  First, soy sauce cake mixed with appropriate amounts of soybeans, wheat and rice bran and salt solution are mixed well in the moromi production tank 2 by adjusting the mixing ratio, and transferred to the fermentation tank 3 with a predetermined transfer amount by the pump 2p. . The soy sauce cake is fermented in the fermentation tank 3 under predetermined conditions to produce soy sauce. Next, the obtained soy sauce is transferred to the pressing machine 4 with a predetermined transfer amount by the pump 3p, and pressed under predetermined conditions with the pressing machine 4 to separate the liquid component and the solid component in the soy sauce. Get refined soy sauce and soy sauce cake. The soy sauce cake is discharged from the pressing machine 4, and the purified soy sauce is transferred to the soy sauce tank 5 by a pump 4p with a predetermined transfer amount.

  The purified soy sauce thus transferred to the soy sauce tank 5 is transferred to the dialysis treatment facility 1 by a pump 5p with a predetermined transfer amount. Conventionally, here, processing that combines reverse osmosis membrane treatment and electrodialysis treatment, electrodialysis treatment using a bipolar membrane, and the like have been performed. In this embodiment, the dialysis treatment equipment 1 is provided. Dialysis treatment is performed with the mosaic charged membrane 10. Thus, performing the dialysis treatment with the mosaic charged membrane 10 is one of the major features of this embodiment.

  The mosaic charged membrane used in the dialysis treatment is a membrane having a cationic polymer component and an anionic polymer component, and having ion channels penetrating the front and back of the membrane and adjacent to each other. The mosaic charged membrane is an excellent functional membrane that can transmit ions through the ion channel, but cannot transmit low molecular weight organic substances or non-ions, or transmits only a small amount. .

Thus, one mosaic charged membrane is used, and cations such as Na ⁺ , K ⁺ , Mg ²⁺ , Ca ²⁺ , Al ³⁺ , and Cl ⁻ , F ⁻ , Br ⁻ , NO ₃ ⁻ , SO ₄ ^{2. -,} it is possible to transmit anions both such PO ₄ ^3-, without requiring a long time in the transmission, it is not necessary to apply a large pressure or flow of electricity from the outside. Therefore, the temperature of the refined soy sauce (target food) does not increase during the treatment, and there is no possibility of affecting the quality and flavor of the refined soy sauce (target food). Moreover, among these cations and anions, the salt components Na ⁺ and Cl ⁻ have a particularly high permeability compared to other ions, so that these Na ⁺ and Cl ⁻ selectively permeate through the mosaic charged membrane. It is efficiently removed from refined soy sauce (target food). Thus, when dialysis treatment is performed with such a mosaic charged membrane, the salt content in the refined soy sauce (target food) can be reliably reduced while maintaining its quality and flavor, and the running cost is reduced. It can also be suppressed.

As shown in FIG. 1, the liquid tanks 1A and 1B in the dialysis treatment facility 1 are partitioned by a mosaic charged membrane 10, and purified soy sauce is transferred to the liquid tank 1A. Inject dialysis water. In each ion channel in the mosaic charged membrane 10, either a cation or an anion preferentially permeates, but both ions permeate as a whole membrane. However, as described above, Na ⁺ and Cl ⁻ are particularly highly permeable compared to other ions, so that they easily penetrate into the dialysis water side in the liquid tank 1B and are purified soy sauce in the liquid tank 1A. Removed from.

  There is no particular limitation on the mosaic charged membrane used in the present embodiment, and it is sufficient that it is composed of a cationic polymer component and an anionic polymer component. For example, the mosaic charged membrane is composed of a cation exchange resin and an anion exchange resin. Preferably used.

  There is no particular limitation on the shape and distribution of each ion exchange resin constituting the mosaic charged membrane. For example, a granular cation exchange resin and a granular anion exchange resin are random as shown in the schematic diagram of FIG. And a mosaic charged film in which a cation exchange resin and an anion exchange resin are alternately arranged in layers as shown in the schematic diagram of FIG.

  The mosaic charged membrane 10 a shown in FIG. 3 is a membrane in which cation exchange resin particles 11 and anion exchange resin particles 12 are randomly dispersed in a film forming polymer 13. For example, the mosaic charged membrane 10a is formed by mixing a film-forming polymer, a solvent, a cation exchange resin, and an anion exchange resin, and dispersing the cation exchange resin and the anion exchange resin in a polymer solution to form a uniform polymer dispersion. After the preparation, the polymer dispersion can be applied to a substrate, stretched, dried and coagulated, and the solvent can be removed from the obtained film and washed. When preparing such a polymer dispersion, a method of dispersing a cation exchange resin and an anion exchange resin in a uniform polymer solution obtained by dissolving a film-forming polymer in a solvent, a cation exchange resin and an anion exchange It is possible to prepare a dispersion by dispersing the resin in a solvent, and then to dissolve the film-forming polymer in the dispersion and adopt a method in which the cation exchange resin and the anion exchange resin are dispersed in the polymer solution. it can.

  Examples of the film-forming polymer include a polysulfone-based resin such as polysulfone, polyethersulfone, and polyphenylsulfone that can be formed by heating and drying when forming a mosaic charged film; Polyarylate resins such as polyesters with aliphatic dicarboxylic acids; Polyamide resins such as polymers obtained by polycondensation of diamines with dibasic acids, lactam ring-opening polymerization, polycondensation of aminocarboxylic acids, etc .; Polymers obtained by polycondensation of carboxylic dianhydride and diamine, polyimide resins such as polyetherimide; for example, obtained by reaction of trimellitic anhydride with diisocyanate or reaction of trimellitic anhydride chloride with diamine Polymers and anhydrous trimmers Polyamideimide resin such as aromatic polyamideimide by reaction of oxalic acid and diphenylalkyl diisocyanate; for example, polymer or polyurethane urea obtained by reaction of polyisocyanate such as aliphatic polyisocyanate and polyol such as tetramethylene glycol Polyurethane resins such as resins; Fluorine resins such as polymers in which hydrogen atoms of alkylene main chain such as polytetrafluoroethylene are substituted with fluorine atoms and their sulfonated products; Silicones such as polyalkylsiloxanes such as polymethylsiloxane Examples of such resins are shown. The number average molecular weight of the film-forming polymer is not particularly limited.

  The solvent is not particularly limited as long as it can dissolve the film-forming polymer, and can be appropriately selected according to the type of the film-forming polymer. For example, N-methyl-2-pyrrolidone, N-ethyl-2- Nitrogen-containing organic solvents such as pyrrolidone, N-vinyl-2-pyrrolidone, N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide; dioxane, tetrahydrofuran, etc. Ether type organic solvents; ketone type organic solvents such as methyl ethyl ketone and methyl isobutyl ketone.

As the cation exchange resin dispersed in the polymer solution, for example, a sulfonic acid group (—SO ₃ H), a carboxylic acid group (—COOH), a phosphonic acid group (—PO ₃ H ₂ , —PO ₄ H), Phenol group (—C ₆ H ₄ OH), sulfoethyl group (— (CH ₂ ) ₂ SO ₂ OH), phosphomethyl group (—CH ₂ PO (OH) ₂ ), carboxymethyl group (—OCH ₂ COOH), imino Having an acetic acid group (—N═C (CH ₂ COOH) ₂ ), an iminodiacetic acid ester group (—N═C (CH ₂ COOR) ₂ ), etc., for example, having an ion exchange capacity of about 1 to 2.5 meq / mL An acidic resin can be suitably used.

Examples of the anion exchange resin dispersed in the polymer solution include quaternary ammonium base (—NR ₃ ), tertiary amino group (—NR ₂ ), secondary amino group (—NHR), first Secondary amino group (—NH ₂ ), 2-hydroxypropylamino group (—OC ₂ H ₄ N (C ₂ H ₅ ) CH ₂ CH (OH) CH ₃ ), triethylamino group (— (CH ₂ ) ₂ N ( C ₂ H _{5) 3),} polyethylene imino group _{(- (CH 2 CH 2 NH} ) x CH 2 CH 2 NH 2), diethylaminoethyl group _{(- (CH 2) 2 N} (C 2 H 5) 2), p - aminobenzyl group _{(-CH 2 -C 6 H 4 -NH} 2), N- methylglucamine group _{(-CH 2 -N (CH 3)} -CH 2 - (C (OH) H) 4 -CH 2 OH For example, a basic resin having an ion exchange capacity of about 1 to 2.5 meq / mL. It can be used to apply.

  In addition, from the viewpoint that the dispersibility of the cation exchange resin and the anion exchange resin in the polymer solution is improved and the characteristics of the resulting mosaic charged membrane are further improved, both of these cation exchange resins and anion exchange resins are, for example, An ion exchange resin having a relatively small particle size such as a pulverized ion exchange resin or an ultrafine ion exchange resin is preferred. As general ion exchange resins, there are many resins having an average particle diameter of usually about 700 to 900 μm, although they vary depending on the type. Considering the dispersibility of the ion exchange resin in the polymer solution and the pressure resistance of the mosaic charged membrane, the average particle size is preferably as small as possible, for example, 500 μm or less, more preferably 400 μm or less, and particularly preferably 300 μm or less. For example, when using a pulverized ion exchange resin, considering the workability when pulverizing the ion exchange resin and the workability when preparing a polymer dispersion from the ion exchange resin, the average particle diameter of the ion exchange resin is It is preferably 0.1 μm or more, more preferably 1 μm or more, and particularly preferably 20 μm or more. In addition, since it is possible to change the salt permeability | transmittance of the mosaic charge membrane obtained by the particle diameter of these ion exchange resins, the purpose of using the mosaic charge membrane, that is, in the target food to be treated with the mosaic charge membrane It is preferable to appropriately select and use an ion exchange resin such as a pulverized ion exchange resin or an ultrafine ion exchange resin having a suitable particle size according to the salt content of the desired low salt food or the salt content of the target low salt food. In the case of using a pulverized ion exchange resin as the ion exchange resin, there is no particular limitation on the pulverization method of the ion exchange resin, and it is preferable to select a pulverization method as appropriate according to the type of the ion exchange resin.

  It is preferable to appropriately change the type (combination) and the use ratio of the cation exchange resin and the anion exchange resin according to the salt content in the target food, the type of ions other than the salt component, and the like. Moreover, it is preferable to change suitably the kind and usage ratio of the said film formation polymer and a solvent in consideration of the kind and total amount of these ion exchange resins.

  The obtained polymer dispersion liquid is allowed to stand, for example, or defoamed using a centrifuge, and then applied onto a substrate having a smooth surface by, for example, a bar coating method, a spray coating method, a spin coating method, or the like. The film is stretched to form a film having a thickness of about 0.05 to 1 mm. After drying and coagulating this at a desired temperature and time, the solvent is removed from the resulting film, and a cleaning process is performed to obtain a thickness of about 0.05 to 1 mm, as shown in FIG. A mosaic charged membrane is obtained.

  Further, as a mosaic charged membrane in which granular ion exchange resins as described above are randomly distributed, an ion selective surface layer is provided on one side as shown in the schematic diagram of FIG. Mosaic charged membranes having properties (selectivity based on differences in ionic valence) can also be used. As shown in FIG. 4, the mosaic charged membrane 10 b has an ion-selective surface layer on one side of a membrane 14 in which cation exchange resin particles 11 and anion exchange resin particles 12 are randomly dispersed in a membrane-forming polymer 13. 15 is provided.

  The mosaic charged membrane 10b shown in FIG. 4 is manufactured in the same manner as the mosaic charged membrane 10a shown in FIG. 3, for example, and is supported on one side of the membrane that has been subjected to the cleaning treatment, as described below, and if necessary. A polymer of a body and a charged polymer solution mixed with a solvent are applied and stretched by, for example, a bar coating method, a spray coating method, a spin coating method, etc., dried and solidified, and an ion having a thickness of about 10 to 200 μm. It can be produced by providing a selective surface layer.

  The ion-selective surface layer preferably contains an arbitrary chargeable polymer depending on, for example, the type of ions other than the salt component contained in the target food.

Mosaic charged membranes with selectivity for cations such as Na ⁺ , K ⁺ , Ca ²⁺ , Mg ²⁺ , and Al ³⁺ are, for example, polyethyleneimine, or quaternary on any polymer main chain. Ammonium base (—NR ₃ ), tertiary amino group (—NR ₂ ), secondary amino group (—NHR), primary amino group (—NH ₂ ), 2-hydroxypropylamino group (—OC _{2) H 4 N (C 2 H 5} ) CH 2 CH (OH) CH 3), triethyl amino group _{(- (CH 2) 2 N} (C 2 H 5) 3), polyethylene imino group (- (CH ₂ CH ₂ NH _{) x CH 2 CH 2 NH 2} ), diethylaminoethyl group _{(- (CH 2) 2 N} (C 2 H 5) 2), p- aminobenzyl group _{(-CH 2 -C 6 H 4 -NH} 2), N - methylglucamine group _{(-CH 2 -N (CH 3)} -CH 2 - (C (OH) H _4, such as -CH ₂ OH) polymers having such, those positive ion-selective surface layer containing a charged polymer is provided is preferable.

On the other hand, as a mosaic charged film to which selectivity for anions such as Cl ⁻ , F ⁻ , Br ⁻ , NO ₃ ⁻ , SO ₄ ²⁻ and PO ₄ ³⁻ is given, for example, polyacrylic acid, polymethacrylic acid, , For example, a sulfonic acid group (—SO ₃ H), a carboxylic acid group (—COOH), a phosphonic acid group (—PO ₃ H ₂ , —PO ₄ H), a phenol group (—C ₆ ) on an arbitrary polymer main chain. H ₄ OH), sulfoethyl group (— (CH ₂ ) ₂ SO ₂ OH), phosphomethyl group (—CH ₂ PO (OH) ₂ ), carboxymethyl group (—OCH ₂ COOH), iminodiacetic acid group (—N═ An ion-selective surface layer containing a negatively charged polymer, such as a polymer having C (CH ₂ COOH) ₂ ), an iminodiacetic ester group (—N═C (CH ₂ COOR) ₂ ), etc., was provided. Those are preferred.

  Since many of these chargeable polymers are water-soluble, usually, for example, polyvinyl alcohol, polysulfone resin, polyarylate resin, polyamide resin, polyimide resin, polyamideimide resin, polyurethane resin, It is preferable to select as appropriate from, for example, polymers exemplified as the film-forming polymer, such as a fluorine-based resin and a silicone-based resin, and use it as a support.

  The mosaic charged membrane in which the granular cation exchange resin and the granular anion exchange resin as shown in FIGS. 3 and 4 are randomly distributed has an application temperature range of about 10 to 80 ° C. in the dialysis treatment, for example. Therefore, there is an advantage that the processing temperature can be appropriately changed depending on the quality of the target food or the quality of the target low-salt food.

  Further, the operation pressure during the dialysis treatment does not need to be set to a high pressure as in, for example, the conventional reverse osmosis membrane treatment, and may be a low pressure of 2 MPa or less, as will be described later. Since the mosaic charged membrane in which the granular cation exchange resin and the granular anion exchange resin are randomly distributed has excellent pressure resistance, when such a mosaic charged membrane is used, dialysis treatment is performed. It is also possible to set the operating pressure at this time to a high pressure.

  The mosaic charged membrane 10c shown in FIG. 5 is one in which the cation exchange resin 16 and the anion exchange resin 17 are alternately arranged in layers. The mosaic charged membrane 10c is prepared, for example, by preparing a block copolymer from a polymer capable of introducing a cation exchange group and a polymer capable of introducing an anion exchange group, and before or after film formation, the cation exchange group and the anion. It can be produced by a method such as introducing an exchange group, crosslinking each block if necessary, and using a polymer solution in which the block copolymer is dissolved in a solvent, and evaporating the solvent to form a film. .

Examples of the polymer capable of introducing a cation exchange group include a sulfonic acid group (—SO ₃ H), a carboxylic acid group (—COOH), a phosphonic acid group (—PO ₃ H ₂ , —PO ₄ H), a phenol group ( -C ₆ H ₄ OH), sulfoethyl _{(- (CH 2) 2 SO} 2 OH), phosphomethyl group _{(-CH 2 PO (OH) 2} ), carboxymethyl group (-OCH ₂ COOH), iminodiacetic acid group ( A polymer capable of introducing a cation exchange group such as —N═C (CH ₂ COOH) ₂ ) or iminodiacetic ester group (—N═C (CH ₂ COOR) ₂ ) can be used as appropriate.

Examples of the polymer capable of introducing an anion exchange group include a quaternary ammonium base (—NR ₃ ), a tertiary amino group (—NR ₂ ), a secondary amino group (—NHR), and a primary amino group. (—NH ₂ ), 2-hydroxypropylamino group (—OC ₂ H ₄ N (C ₂ H ₅ ) CH ₂ CH (OH) CH ₃ ), triethylamino group (— (CH ₂ ) ₂ N (C ₂ H _{5) 3),} polyethylene imino group _{(- (CH 2 CH 2 NH} ) x CH 2 CH 2 NH 2), diethylaminoethyl group _{(- (CH 2) 2 N} (C 2 H 5) 2), p- aminobenzyl Groups (—CH ₂ —C ₆ H ₄ —NH ₂ ), N-methylglucamine groups (—CH ₂ —N (CH ₃ ) —CH ₂ — (C (OH) H) ₄ —CH ₂ OH), etc. A polymer capable of introducing an anion exchange group can be appropriately used.

  The kind (combination) and the use ratio of the polymer capable of introducing the cation exchange group and the polymer capable of introducing the anion exchange group are appropriately changed according to the salt content in the target food or the kind of ions other than the salt component. It is preferable to do. In addition, it is preferable to appropriately change the conditions for preparing the block copolymer according to the type of the polymer.

  The solvent for preparing the polymer solution from the block copolymer is not particularly limited, and for example, benzene, toluene, xylene, cyclohexane, dioxane, tetrahydrofuran and the like that can sufficiently dissolve the block copolymer can be used. The type of the solvent may be determined according to the type of polymer constituting the block copolymer.

  The polymer solution is used to form a film by evaporating the solvent on mercury, for example. In order to improve the strength of the resulting mosaic charged film, for example, a thin film made of polyvinyl chloride, polyethylene, polypropylene, or the like is used as a support member. A film may be formed.

  Before or after film formation as described above, a cation exchange group and an anion exchange group are introduced into each polymer site in the block copolymer to form a crosslinked structure as necessary. The introduction and crosslinking of these ion exchange groups can be performed by appropriately selecting conditions according to the type of ion exchange group and the structure of the polymer site.

  In the dialysis treatment in the present embodiment, for example, a mosaic charged membrane in which the granular cation exchange resin and the granular anion exchange resin shown in FIG. 3 and FIG. 4 are randomly distributed, the cation exchange resin shown in FIG. A mosaic charged membrane in which anion exchange resins are alternately arranged in layers can be used without any particular limitation, but among these mosaic charged membranes, it has pressure resistance, durability, salt permeability, ion selectivity, For example, the granular cation exchange resin shown in FIG. 3 and FIG. 4 can be processed regardless of the salt content and the concentration of ions other than the salt component in the target food. A mosaic charged membrane in which granular anion exchange resins are randomly distributed is preferable. Among these, it is particularly preferable that the cation exchange resin and the anion exchange resin use a mosaic charged membrane which is an ion exchange resin having an average particle diameter of 500 μm or less.

  In addition, considering the low chlorination effect due to dialysis treatment, the salt permeability of the mosaic charged membrane depends on the salt content in the food subject to dialysis treatment, the type of ions other than the salt component, dialysis treatment conditions described later, etc. Although somewhat different, it is preferably 50% or more, more preferably 70% or more, and particularly preferably 90 to 99% salt permeability can be achieved.

  The operation pressure at the time of dialysis treatment in the dialysis treatment facility 1 can be set low by using a mosaic charged membrane, operates sufficiently at low cost, and satisfactory dialysis treatment results can be obtained. For example, it is preferably 2 MPa or less, more preferably 1.8 MPa or less. In addition, when the operation pressure is too low, it may take time for the dialysis treatment. Therefore, the pressure is preferably set to 0.1 MPa or more, more preferably 0.3 MPa or more. In the production system shown in FIG. 1, the operating pressure of the pump 5p when the purified soy sauce is transferred from the soy sauce tank 5 to the dialysis treatment equipment 1 is also about 0.1 to 2 MPa, and further 0.3 to 1. The pressure is preferably about 8 MPa.

  Further, other dialysis treatment conditions are not particularly limited as long as a sufficient treatment effect is obtained, that is, as long as the salt content of the target food is sufficiently reduced, depending on the quality of the food and the quality of the target low-salt food. For example, the processing temperature (food temperature) is preferably about 10 to 80 ° C., more preferably about 15 to 60 ° C. The processing temperature may be set as appropriate in advance within a range where the quality and flavor of the food do not change. In this embodiment, the food temperature does not rise unexpectedly during the processing. Therefore, for example, when purified soy sauce is dialyzed with a mosaic charged membrane, there is no problem in the conventional electrodialysis method in which the amino acid component in the soy sauce is damaged and the flavor is lowered.

  In the low salt food production method and low salt food production system using soy sauce as an example shown in the schematic configuration diagram of FIG. 1, only one dialysis treatment facility 1 is provided, but as another example of this embodiment, The dialysis treatment can be performed a plurality of times in a production system provided with a plurality of dialysis treatment facilities.

  FIG. 2A shows an example of a low salt food production method and a low salt food production system when two dialysis treatment facilities 1 and 1 are provided in parallel. FIG. 2B shows two dialysis treatment facilities 1 and 1. An example of a low salt food production method and a low salt food production system provided in series is shown as a partial schematic configuration diagram from the soy sauce tank 5 to the front of the pumps 8p and 9p, respectively. As shown in FIG. 2A and FIG. 2B, both of the two dialysis treatment facilities 1 and 1 are provided with a mosaic charged membrane 10, and purified soy sauce in the soy sauce tank 5 is transferred by a pump 5p at a predetermined transfer amount. The two dialysis treatment facilities 1 and 1 are simultaneously subjected to dialysis treatment (FIG. 2A) or sequentially in the first dialysis treatment facility 1 and the second dialysis treatment facility 1 (FIG. 2B). .

  2A and 2B show the case where the dialysis treatment is performed twice in two dialysis treatment facilities, but the number of dialysis treatments is not limited, and the salt content in the target food, the target low salt food It is preferable to change appropriately according to the salt content, the amount of food to be processed, and the like. In addition, parallel processing and serial processing can be appropriately combined.

Thus, the purified soy sauce (processed product) in the liquid tank 1A after the dialysis treatment is processed by the pump 1Ap from the dialysis treatment equipment 1 as a low salt soy sauce from which the salt components Na ⁺ and Cl ⁻ are sufficiently removed. It is transferred to the low salt soy sauce tank 6. The low salt soy sauce is once stored in the low salt soy sauce tank 6 and then transferred to the next process such as burning by the pump 6p. In addition, although it may heat after dialysis treatment (desalting treatment) in this way, dialysis treatment (desalting treatment) may be performed on the soaked soy sauce that has been fired.

On the other hand, the dialysis water in the liquid tank 1B is discharged as a saline solution containing Na ⁺ and Cl ⁻ from the dialysis treatment equipment 1 by the pump 1Bp and once stored in the saline tank 7. Since this salt water can be reused as salt water for moromi, after passing through the pump 7p, it is appropriately sterilized as necessary and transferred to the moromi production tank 2 by the pump 8p. Further, when it is not necessary to reuse the saline solution, the solution is transferred to the wastewater treatment facility by the pump 9p after passing through the pump 7p.

  In addition, although the salt content in common soy sauce is about 17 to 20 weight% normally, for example, in this embodiment, when low salt soy sauce is manufactured with the low salt soy sauce production system shown in FIG. It is preferable to reduce the salt content of soy sauce to about 10% by weight or less, and further to about 8% by weight or less. That is, although it differs somewhat depending on the type and application of the target low salt food, the salt content of the obtained low salt food is reduced to 70% or less, and further to 60% or less with respect to the salt content of the food to be processed. It is preferable to make it. If the salt content in the low-salt food is too low, the effects derived from the salt content of the food may be hindered in the first place. Dialysis treatment is preferably performed so that the salt content of the food is 20% or more. Thus, reducing the salt content of the target food as desired can be achieved by appropriately adjusting the type of the mosaic charged membrane, dialysis treatment conditions, and the like.

  As described above, the method for producing low salt soy sauce and the system for producing low salt soy sauce are described as typical examples, and according to the method for producing low salt food and the system for producing low salt food of this embodiment, Therefore, it is possible to reliably and easily obtain a high-quality low-salt food in which the salt content is sufficiently reduced at low energy and at low cost and the original good flavor is maintained. At the same time, by reducing the amount of coloring components in the food, it is possible to lighten the food and to obtain a light-colored low-salt food.

  In the low salt food production system of the present embodiment, although not shown in the schematic configuration diagrams of FIGS. 1, 2A, and 2B, the dialysis treatment facility 1 and the like so that the entire system can be operated efficiently, safely and accurately. Each of these facilities and various tank pumps are controlled and operated.

  Below, the mosaic charged membrane used for the manufacturing method of the low salt food of this invention and the low salt food manufacturing system is demonstrated in detail based on a manufacture example.

Production Examples 1-6 (Manufacture of Mosaic Charged Membrane)
The raw materials 1 to 4 shown below were prepared. The raw material 3 and the raw material 4 were each pulverized so as to have an average particle diameter shown in Table 1, and used as a pulverized ion exchange resin.
Raw material 1 (film-forming polymer):
Polysulfone (manufactured by Aldrich, number average molecular weight: about 22000)
Raw material 2 (solvent):
N-methyl-2-pyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd.)
Raw material 3 (cation exchange resin):
Sulfonic acid group-containing ion exchange resin (trade name: Amberlite IR-120B, manufactured by Organo Corporation,
(Ion exchange capacity: 1.9 meq / mL)
Raw material 4 (anion exchange resin):
Quaternary ammonium base-containing ion exchange resin (trade name: Amberlite IRA-410J, manufactured by Organo Corporation,
(Ion exchange capacity: 1.4 meq / mL)

  Table 1 shows the amount of raw materials 1 to 4 used and the average particle diameter of raw materials 3 and 4 together.

  First, the raw material 1 and the raw material 2 were sufficiently heated and stirred using a stirrer with a heater at about 60 ° C. until a uniform polymer solution was obtained. While maintaining the obtained polymer solution at 60 ° C., the raw material 3 and the raw material 4 that were pulverized to adjust the particle diameter were added thereto, and the mixture was sufficiently heated and stirred until the raw material 3 and the raw material 4 were dispersed in the polymer solution. Thus, a uniform polymer dispersion was obtained.

  The obtained polymer dispersion was left to stand until bubbles disappeared in the liquid, defoamed, cast on a glass plate, and stretched to a uniform thickness of about 0.5 mm by a bar coating method. This was dried at 30 ° C. for 24 hours to be solidified, and then the solvent as the raw material 2 was removed from the obtained film and washed with distilled water to obtain a mosaic charged film.

  The obtained mosaic charged film was free from cracks, chips and scratches and had a good appearance. The thickness is shown in Table 1.

Production Example 7 (Manufacture of Mosaic Charged Membrane with Ion Selective Surface Layer)
Polyethyleneimine (trade name: polyethyleneimine P-70, manufactured by Wako Pure Chemical Industries, Ltd., 30% polyethyleneimine solution, number average molecular weight: about 70,000) is used as a positively charged polymer, and as a support for polyethyleneimine An ion selective surface layer was formed using polyvinyl alcohol (Wako Pure Chemical Industries, Ltd., polymerization degree: 1000).

  Polyvinyl alcohol was dissolved in a 70% aqueous solution of dimethyl sulfoxide (manufactured by Wako Pure Chemical Industries, Ltd.), and polyethylene imine was added to this solution so that the ratio of polyvinyl alcohol to polyethylene imine was 20: 1 (weight ratio). A polymer solution was prepared by addition.

  The obtained polymer solution was applied and stretched on one side of the washed film obtained in Production Example 4 by a bar coating method, and this was dried at room temperature for about 1 hour to solidify, and then the obtained film Then, the solvent was removed from the solution and washed with distilled water to obtain a mosaic charged membrane provided with an ion-selective surface layer having a thickness of about 150 μm.

  The obtained mosaic charged film was free from cracks, chips and scratches and had a good appearance. The thickness is shown in Table 1.

  The low-salt food production method and low-salt food production system of the present invention can be effectively used for the production of high-quality low-salt foods that maintain good flavor.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram which shows an example of the manufacturing method of a low salt food based on the 1st Embodiment of this invention, and a low salt food manufacturing system used for this, and shows an example of the manufacturing method of a low salt soy sauce, and its manufacturing system. Schematic configuration diagram It is a partial schematic block diagram which shows an example of the manufacturing method of a low salt food based on the 1st Embodiment of this invention, and an example of the low salt food manufacturing system used for this, An example of the manufacturing method of a low salt soy sauce, and an example of the manufacturing system Partial schematic configuration diagram It is a partial schematic block diagram which shows an example of the manufacturing method of a low salt food based on the 1st Embodiment of this invention, and an example of the low salt food manufacturing system used for this, An example of the manufacturing method of a low salt soy sauce, and an example of the manufacturing system Partial schematic configuration diagram The schematic diagram which shows an example of the mosaic charge film used for this invention The schematic diagram which shows an example of the mosaic charge film used for this invention The schematic diagram which shows an example of the mosaic charge film used for this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Dialysis treatment equipment 1A, 1B Liquid tank 2 Moromi production tank 3 Fermentation tank 4 Press machine 5 Soy sauce tank 6 Low salt soy sauce tank 7 Saline tank 10, 10a, 10b, 10c Mosaic charged membrane 11 Cation exchange resin particle 12 Anion Exchange resin particles 13 Membrane-forming polymer 14 Membrane 15 Ion selective surface layer 16 Cation exchange resin 17 Anion exchange resin 1Ap, 1Bp Pump 2p, 3p, 4p, 5p, 6p, 7p, 8p, 9p Pump

Claims (7)

A method for producing a low-salt food wherein at least dialysis treatment is performed on the food,
The dialysis treatment is performed with a mosaic charged membrane ,
The mosaic charged membrane has a granular cation exchange resin and a granular anion exchange resin randomly distributed;
The cation-exchange resin and the anion exchange resin, the manufacturing method of the low-salt food both average particle size of Ru 500μm or less of the ion exchange resin der least 20 [mu] m.   The manufacturing method of Claim 1 which performs a dialysis process in multiple times.   The production method according to claim 1 or 2, wherein the dialysis treatment is performed at an operation pressure of 2 MPa or less. The manufacturing method of any one of Claims 1-3 whose salt permeability | transmittance of a mosaic charged membrane is 50% or more. The manufacturing method of any one of Claims 1-4 which reduce the salt content of a low salt food to 70% or less with respect to the salt content of a foodstuff. A low-salt food production system equipped with at least a dialysis treatment facility,
The low-salt food production system used for the production method according to claim 1, wherein the dialysis treatment facility is provided with a mosaic charged membrane. The low salt food production system according to claim 6 , wherein a plurality of dialysis treatment facilities are provided.

Images