WO2021187438A1

WO2021187438A1 - Concentration method for raw material liquid

Info

Publication number: WO2021187438A1
Application number: PCT/JP2021/010432
Authority: WO
Inventors: 友規須賀; 充藤田; あずさ山中
Original assignee: 旭化成株式会社
Priority date: 2020-03-19
Filing date: 2021-03-15
Publication date: 2021-09-23
Also published as: JP2021146297A

Abstract

This concentration method for a raw material liquid includes a raw material concentration step for obtaining a dilution induction solution by bringing a raw material liquid containing a solvent and a solute and an induction solution containing an inducing substance into contact with a forward osmosis membrane, and causing the solvent in the raw material liquid to migrate into the induction solution and also for concentrating the raw material liquid. The forward osmosis membrane is a hollow-fiber membrane. The concentration method for the raw material liquid includes a step for causing the raw material liquid to flow through a hollow portion of the hollow-fiber forward osmosis membrane and causing the induction solution to flow through the outside of the hollow-fiber forward osmosis membrane. When the viscosity of the raw material liquid flowing into the hollow portion of the hollow-fiber forward osmosis membrane is from 20-600 cP, a linear velocity of the raw material liquid flowing into the hollow portion of the hollow-fiber forward osmosis membrane is 0.1-5.0 cm/s.

Description

Method of concentrating raw material liquid

The present invention relates to a raw material liquid concentration system for a food manufacturing process. More specifically, the present invention relates to a method for concentrating a raw material liquid, which concentrates the raw material liquid by separating a part of a solvent from the raw material liquid used for food applications by a forward osmosis method.

Consumer health consciousness in recent years has led to consumer interest in naturally harvested, extracted or concentrated food products. For example, a concentrated liquid obtained by putting a raw material liquid derived from a natural product into an evaporator and heating and evaporating water is added as a sweetener to various dishes, confectionery and the like. However, when the raw material liquid is heated at a high temperature, many components contained in the raw material liquid are altered or disappear, so that there is a problem that the flavor component of the obtained concentrated liquid is deteriorated.
Therefore, a reverse osmosis membrane method is generally used as a method for concentrating the raw material liquid without requiring heating. For example, Patent Documents 1 and 2 describe a method for concentrating maple syrup by a reverse osmosis membrane method.
On the other hand, Patent Document 3 describes a method of concentrating a liquid food by a forward osmosis membrane method.

Japanese Unexamined Patent Publication No. 2003-70448 U.S. Pat. No. 9622505 International Publication No. 2019/098390

However, in the reverse osmosis membrane method, it is necessary to apply a pressure higher than the osmotic pressure of the concentrated solution to the raw material solution, so that the concentrated concentration is limited. Further, in the reverse osmosis membrane method, since a high pressure is applied, the components are easily adsorbed on the membrane, and there is a problem that the membrane performance deteriorates after repeated operation. In addition, for example, liquid food products such as sugar liquids such as maple syrup and honey, coffee extracts, tea extracts, soup stocks, fragrance emulsions, and food oil emulsions have a higher viscosity due to the concentration of the components. .. Therefore, when the hollow fiber membrane module is used for concentration, there is a problem that it becomes difficult to pass the raw material liquid through the flow path, the concentration cannot be efficiently performed, or the performance deteriorates when the module is operated for a long period of time.
An object of the present invention is to solve the above problems.
That is, an object of the present invention is to provide a concentration method capable of efficiently concentrating a raw material liquid by suppressing deterioration or decrease of components even if the raw material liquid has a high viscosity.

In the concentration of the raw material solution using the forward osmosis method, the present inventors control the linear velocity of the raw material solution or the inductive solution according to the viscosity of the raw material solution when moving the solvent from the raw material solution to the inductive solution. The present invention has been made by finding that the separation of the solvent becomes more efficient and that such efficient separation can be stably performed for a long period of time.
The present invention includes the following aspects.

<< Aspect 1 >> A raw material liquid containing a solvent and a solute and an inducing solution containing an inducing substance are brought into contact with each other via a normal osmotic membrane, and the solvent in the raw material liquid is moved into the inducing solution. A method for concentrating a raw material solution, which comprises a raw material solution concentrating step of obtaining a dilution induction solution and concentrating the raw material solution.
The forward osmosis membrane has a hollow thread shape and is in the form of a hollow thread.
The method for concentrating the raw material liquid includes a step of circulating the raw material liquid through the hollow portion of the hollow thread-shaped forward osmosis membrane and circulating the induction solution outside the hollow thread-shaped forward osmosis membrane.
When the viscosity of the raw material liquid flowing into the hollow portion of the hollow thread-like forward osmosis membrane is 20 cP or more and 600 cP or less, the linear velocity of the raw material liquid flowing into the hollow portion of the hollow thread-like forward osmosis membrane is set to 0. 1 cm / s or more and 5.0 cm / s or less,
Method of concentrating raw material liquid.
<< Aspect 2 >> When the viscosity of the raw material liquid flowing into the hollow portion of the hollow thread-like forward osmosis membrane is 20 cP or more and 600 cP or less, the linear velocity of the raw material liquid flowing into the hollow portion of the hollow thread-shaped forward osmosis membrane. The method for concentrating the raw material liquid according to the first aspect, wherein the amount is 0.9 cm / s or more and 3.5 cm / s or less.
<< Aspect 3 >> A raw material liquid containing a solvent and a solute and an inducing solution containing an inducing substance are brought into contact with each other via a normal osmotic membrane, and the solvent in the raw material liquid is moved into the inducing solution. A method for concentrating a raw material solution, which comprises a raw material solution concentrating step of obtaining a dilution induction solution and concentrating the raw material solution.
The forward osmosis membrane has a hollow thread shape and is in the form of a hollow thread.
The method for concentrating the raw material liquid includes a step of circulating the raw material liquid through the hollow portion of the hollow thread-shaped forward osmosis membrane and circulating the induction solution outside the hollow thread-shaped forward osmosis membrane.
The linear velocity of the induction solution flowing into the outside of the forward osmosis membrane is 0.1 cm / s or more and 10 cm / s or less.
Method of concentrating raw material liquid.
<< Aspect 4 >> The method for concentrating a raw material solution according to any one of aspects 1 to 3, wherein the induction solution is an inorganic salt solution containing a divalent cation.
<< Aspect 5 >> The positive osmotic film is a polyether sulfone, a polysulfone, a polyketone, a polyether ether ketone, a polyphenylene ether, a polyvinylidene fluoride, a polyacrylonitrile, a polyimine, a polyimide, a polybenzoxazole, a polybenzoimidazole, and a sulfonated tetrafluoroethylene. The method for concentrating a raw material solution according to any one of aspects 1 to 4, which is a film having a thin film layer containing at least one selected from the group consisting of and polyamide as a main component.
<< Aspect 6 >> A method for concentrating a raw material liquid, wherein the raw material liquid concentrating step is performed in two or more steps in series.
In succession two steps of the raw material solution concentration step is carried out of the two or more stages of the raw material solution concentration step, the raw material liquid flow path cross-sectional area A _d of the forward osmosis membrane used in the subsequent stage of the raw material solution concentration step, preceding the ratio _a d / _{a u} for feed liquid flow path cross-sectional area _{a u} of the forward osmosis membrane is 0.2 to 10,
The method for concentrating a raw material liquid according to any one of aspects 1 to 5.
The ratio of the raw material liquid flow path cross-sectional area A _d, based on the starting material liquid flow path cross-sectional area A _u of forward osmosis membrane used in the preceding stage of the raw material solution concentration step of forward osmosis membrane used in "embodiment 7" the subsequent raw material liquid concentration step The method for concentrating a raw material liquid according to aspect 6, wherein _Ad / _{Au is 2 or more and 8 or less.}
<< Aspect 8 >> In the raw material liquid concentrating step performed in two or more steps in series, the raw material liquid is pumped in order to supply the raw material liquid concentrated in the raw material liquid concentrating step in the previous stage as the raw material liquid in the raw material liquid concentrating step in the subsequent stage. The method for concentrating a raw material liquid according to aspect 6 or 7, wherein one or more liquid pumps are used.
<< Aspect 9 >> Further comprising an induction solution concentration step of removing the solvent from the dilution induction solution to obtain a regeneration induction solution.
The concentrated induction solution obtained in the induction solution concentration step is used again as the induction solution.
The method for concentrating a raw material liquid according to any one of aspects 1 to 8.
<< Aspect 10 >> A induction solution concentration step of removing the solvent from the induction solution to obtain a concentration induction solution.
Further comprising a mixing step of mixing the concentration-inducing solution obtained in the induction solution concentration step with the dilution-inducing solution.
The mixed solution obtained in the mixing step is used again as the induction solution.
The method for concentrating a raw material liquid according to any one of aspects 1 to 8.
<< Aspect 11 >> The method for concentrating a raw material solution according to Aspect 9 or 10, wherein the induction solution concentration step is carried out by an evaporation means.
<< Aspect 12 >> The forward osmosis membrane is formed by contacting the raw material solution with a diluted solution of the induction solution or the solvent whose osmotic pressure is adjusted to be lower than that of the raw material solution via the forward osmosis membrane. The method for concentrating a raw material solution according to any one of aspects 1 to 11, which comprises a first washing step for washing.
13. Aspect 12 according to aspect 12, further comprising a second cleaning step of cleaning the forward osmosis membrane by bringing the solvent into contact with both sides of the forward osmosis membrane after the first cleaning step. Method of concentrating raw material liquid.
<< Aspect 14 >> A food product which is a concentrated solution of a solute containing sugar and a raw material liquid containing a liquid medium.
The concentrate is
Brix value is 50 or more and
The absorbance at 450 nm in ultraviolet-visible spectroscopy is 0.1 or more and 1.0 or less.
Grocery.
<< Aspect 15 >> The food product according to Aspect 14, wherein the absorbance at 450 nm in the ultraviolet-visible spectroscopic analysis of the concentrated solution is 0.2 or more and 0.8 or less.
<< Aspect 16 >>
The food product according to aspect 14 or 15, wherein the raw material liquid is a maple liquid or a coconut liquid endosperm.

In the concentration method of the present invention, when the raw material liquid is concentrated with a forward osmosis membrane, the linear velocity of the raw material liquid or the induction solution is controlled according to the viscosity of the raw material liquid, so that the components contained in the raw material liquid are efficiently increased. It can be concentrated to a high concentration and can be operated for a long period of time. Moreover, since the concentration by the forward osmosis membrane does not require heating, it is possible to significantly reduce the coloration, alteration, loss due to volatilization, etc. of the contained components due to heat when concentrating the liquid food.

FIG. 1 is a conceptual diagram for explaining an example of an embodiment of the raw material liquid concentration system of the present invention. FIG. 2 is a conceptual diagram for explaining another example of the embodiment of the raw material liquid concentration system of the present invention. FIG. 3 is a conceptual diagram for explaining still another example of the embodiment of the raw material liquid concentration system of the present invention. FIG. 4 is a conceptual diagram for explaining still another example of the embodiment of the raw material liquid concentration system of the present invention. FIG. 5 is a conceptual diagram for explaining still another example of the embodiment of the raw material liquid concentration system of the present invention. FIG. 6 is a conceptual diagram for explaining still another example of the embodiment of the raw material liquid concentration system of the present invention. FIG. 7 is a conceptual diagram for explaining still another example of the embodiment of the raw material liquid concentration system of the present invention. FIG. 8 is a conceptual diagram for explaining still another example of the embodiment of the raw material liquid concentration system of the present invention. FIG. 9 is a conceptual diagram for explaining still another example of the embodiment of the raw material liquid concentration system of the present invention. FIG. 10 is a conceptual diagram for explaining still another example of the embodiment of the raw material liquid concentration system of the present invention. FIG. 11 is a conceptual diagram for explaining still another example of the embodiment of the raw material liquid concentration system of the present invention. FIG. 12 is a conceptual diagram for explaining still another example of the embodiment of the raw material liquid concentration system of the present invention. FIG. 13 is a conceptual diagram for explaining still another example of the embodiment of the raw material liquid concentration system of the present invention. FIG. 14 is a conceptual diagram for explaining still another example of the embodiment of the raw material liquid concentration system of the present invention. FIG. 15 is a conceptual diagram for explaining still another example of the embodiment of the raw material liquid concentration system of the present invention. FIG. 16 is a conceptual diagram for explaining still another example of the embodiment of the raw material liquid concentration system of the present invention. FIG. 17 is a conceptual diagram for explaining still another example of the embodiment of the raw material liquid concentration system of the present invention.

Hereinafter, an embodiment of the present invention (hereinafter, also referred to as the present embodiment) will be specifically described in detail with reference to non-limiting examples. In the drawings of the present disclosure, the elements with the same reference numerals are intended to have the same configuration or function as each other.

<Method of concentrating raw material liquid>
In the method for concentrating the raw material liquid of the present embodiment, the raw material liquid containing the solvent and the solute and the inducing solution containing the inducing substance are brought into contact with each other through a normal osmotic membrane, and the solvent in the raw material liquid is put into the inducing solution. It includes a raw material solution concentration step of moving to obtain a dilution-inducing solution and concentrating the raw material solution. This raw material liquid concentrating step includes a step of circulating the raw material liquid through the hollow portion of the hollow filament-shaped forward osmosis membrane and circulating the inductive solution outside the hollow filament-shaped forward osmosis membrane.
Here, in the method for concentrating the raw material liquid of the present embodiment, in the raw material liquid concentrating step, when the viscosity of the raw material liquid flowing into the hollow portion of the hollow thread-like forward osmosis membrane is 20 cP or more and 600 cP or less, the hollow thread-like The linear velocity of the raw material liquid flowing into the hollow portion of the forward osmosis membrane is 0.1 cm / s or more and 5.0 cm / s or less.
According to another embodiment of the present embodiment, in the raw material liquid concentration step, the linear velocity of the induction solution flowing into the outside of the forward osmosis membrane is 0.1 cm / s or more and 10 cm / s or less.
In the raw material liquid concentration step, the linear velocity control of the raw material solution and the linear velocity control of the inductive solution may be performed in an overlapping manner.

In the process of concentrating the raw material liquid, the viscosity of the solution gradually increases as the degree of concentration (concentration ratio) increases. In the case of the conventional method, when the viscosity of the solution is 20 cP or more, it becomes difficult to pass the raw material liquid through the flow path, and it is not possible to concentrate efficiently. Further, if the product is operated for a long period of time in such a state, the concentration performance deteriorates with time. Further, when the viscosity of the solution is 600 cP or more, it becomes difficult to feed the liquid by the liquid feeding pump.

In the method for concentrating the raw material liquid of the present embodiment, when the viscosity of the raw material liquid flowing into the hollow portion of the hollow thread-like forward osmosis membrane is 20 cP or more and 600 cP or less, the linear velocity of the raw material liquid flowing into the hollow portion of the forward osmosis membrane. Is 0.1 cm / s or more and 5.0 cm / s or less, preferably 0.9 cm / s or more and 3.5 cm / s or less.
Although the reason is not clear, when this linear velocity is 0.1 cm / s or more, the osmotic pressure of the raw material liquid is maintained low when the solvent in the raw material liquid moves to the induction solution through the forward osmosis membrane. Therefore, the water permeability is maintained at a high level. Presumably, by adjusting the linear velocity of the raw material liquid to the above range, the retention of the raw material liquid on the surface of the forward osmosis membrane (in the preferred embodiment of the present invention, the surface of the separation active layer on the support layer) is suppressed. It is inferred that.
Further, if this linear velocity is 5.0 cm / s or less, the pressure loss when the raw material liquid passes through the hollow portion of the hollow thread-like forward osmosis membrane is reduced, and the pressure applied from the inside to the outside of the membrane is reduced. Can be done. Therefore, it is possible to suppress clogging and deterioration of the film, which facilitates long-term operation.

On the other hand, the linear velocity of the induction solution flowing into the outside of the forward osmosis membrane is preferably 0.1 cm / s or more and 10 cm / s or less, more preferably 1.0 cm / s or more and 5.0 cm / s or less, and further. It is preferably 1.5 cm / s or more and 4.0 cm / s or less. Although the reason is not clear, when this linear velocity is 0.1 cm / s or more, the osmotic pressure of the inducing solution is maintained high when the solvent in the raw material liquid moves to the inducing solution through the forward osmosis membrane. Therefore, the water permeability is maintained at a high level. Presumably, by adjusting the linear velocity of the inducing solution to the above range, the retention of the inducing solution on the surface of the forward osmosis membrane (in the preferred embodiment of the present invention, the surface of the separation active layer on the support layer) is suppressed. It is inferred that.
Further, when this linear velocity is set to 10 cm / s or less, the pressure loss when the inductive solution passes outside the hollow thread-like forward osmosis membrane is reduced, and the pressure applied from the outside to the inside of the membrane can be reduced. Therefore, destruction of the forward osmosis membrane (in a preferred embodiment of the present invention, separation of the support layer and the separation active layer on the support layer) can be suppressed, and long-term operation becomes easy.

In the method for concentrating the raw material liquid of the present embodiment, the raw material liquid containing the solvent and the solute and the inducing solution containing the inducing substance are brought into contact with each other through a normal osmotic membrane, and the solvent in the raw material liquid is put into the inducing solution. It is preferably carried out using a raw material solution concentrating system having a normal osmotic membrane unit that is moved to obtain a dilution inducing solution and concentrates the raw material solution.
Hereinafter, a raw material liquid concentrating system preferably used for carrying out the raw material liquid concentrating method of the present embodiment will be described.

<< Raw material liquid concentration system >>
In the raw material liquid concentration system for carrying out the raw material liquid concentration method of the present embodiment,
The forward osmosis membrane is hollow filamentous and
The forward osmosis membrane unit has a function of allowing the raw material liquid to flow through the hollow portion of the hollow filament-like forward osmosis membrane and the inducing solution to flow outside the hollow filament-like forward osmosis membrane.
When the viscosity of the raw material liquid flowing into the hollow portion of the hollow thread-shaped forward osmosis membrane is 20 cP or more and 600 cP or less, the linear velocity of the raw material liquid flowing into the hollow portion of the hollow thread-shaped forward osmosis membrane is 0.1 cm / s or more. It has a function of 5.0 cm / s or less.

According to another embodiment of this raw material liquid concentration system, the raw material having a function of setting the linear velocity of the inducing solution flowing into the outside of the forward osmosis membrane to 0.1 cm / s or more and 10 cm / s or less in the forward osmosis membrane unit. It may be a liquid concentration system.
The forward osmosis membrane unit may have a function of controlling the linear velocity of the raw material solution and a function of controlling the linear velocity of the inductive solution in an overlapping manner.

In the present specification, the linear velocity of the raw material liquid is a value Y / A [] obtained by dividing ^{the flow velocity Y [cm 3} / s] of the raw material liquid by the raw material liquid flow path cross-sectional area A [cm ^{2] of the forward osmosis membrane unit.} It is defined as [cm / s]. Here, the cross-sectional area of the raw material liquid flow path of the forward osmosis membrane unit is equal to the total cross-sectional area of the hollow portion of the hollow filamentous forward osmosis membrane contained in the unit.
The linear velocity of the inductive solution is defined as a value Z / B [cm / s] obtained by dividing ^{the flow velocity Z [cm 3} / s] of the inductive solution by the cross-sectional area B [cm ^{2] of the inductive solution flow path of the forward osmosis membrane unit.} Defined. Here, the inductive solution flow path cross-sectional area B of the forward osmosis membrane unit is equal to the value obtained by subtracting the total cross-sectional area of the hollow filamentous forward osmosis membrane contained in the unit from the cross-sectional area of the inner space of the housing of the unit. ..

In the raw material liquid concentrating system of the present embodiment, as a function of controlling the linear velocity of the raw material liquid or the inductive solution, a known device or a combination thereof may be appropriately selected and used. For example, a flow velocity measuring device and a means for feeding back the measurement result of the flow velocity measuring device to the flow rate adjustment of the liquid feed pump can be exemplified. The means for feeding back the measurement result of the flow velocity measuring device to the flow rate adjustment of the liquid feed pump may be automatic control or manual control.

In the concentration of the raw material liquid, the forward osmosis membrane unit may be passed once, the raw material liquid concentrated to some extent may be circulated, and the forward osmosis membrane unit may be passed again to further concentrate. Further, such circulation may be repeated to pass the forward osmosis membrane unit three times or more to obtain a highly concentrated concentrated liquid. In such a case, when the degree of concentration of the raw material liquid is low and the viscosity of the raw material liquid is less than 20 cP, it is not necessary to control the linear velocity of the raw material liquid. When the viscosity of the raw material liquid is less than 20 cP, highly efficient concentration is possible without controlling the linear velocity of the raw material liquid.
When the viscosity of the raw material liquid flowing into the hollow portion of the hollow thread-like forward osmosis membrane reaches the range of 20 cP or more and 600 cP or less, the advantageous effect of the present invention is exhibited by adjusting the viscosity of the raw material liquid to the above range. Will be done.
On the other hand, the advantageous effect of the present invention is also exhibited by setting the linear velocity of the induction solution flowing into the outer portion of the hollow thread-like forward osmosis membrane to 0.1 cm / s or more and 10 cm / s or less.

In the raw material liquid concentration system of the present embodiment, two or more forward osmosis membrane units may be arranged. In this case, the two or more forward osmosis membrane units may be arranged in series or in parallel, or a set of two or more forward osmosis membrane units arranged in parallel may be arranged in series.
By arranging two or more forward osmosis membrane units in parallel, the processing amount can be increased while maintaining the concentration efficiency of the raw material liquid concentration system.
By arranging two or more forward osmosis membrane units in series, the concentration efficiency for each pass can be further increased.

However, in the process of concentrating the raw material liquid, the viscosity of the solution gradually increases as the degree of concentration progresses. In that case, if a plurality of forward osmosis membrane units are arranged in series, it becomes difficult for the solution to pass through the forward osmosis membrane unit on the downstream side, and efficient concentration cannot be performed, or the performance deteriorates due to long-term operation. There is. In order to avoid this, when two or more forward osmosis membrane units are arranged in series in the raw material liquid concentration system of the present embodiment, they are arranged on the downstream side of the flow of the raw material liquid in the two adjacent forward osmosis membrane units. All forward osmosis membrane unit raw liquid flow path cross-sectional area a _d of the ratio a _{d /} a _u for raw liquid flow path cross-sectional area a _u of forward osmosis membrane unit disposed upstream of the raw material liquid flow, 0 It is preferably 2 or more and 10 or less, and preferably 1 time or more and 8 times or less.

Although the reason is not clear, when this ratio _Ad / _Au is 0.2 or more, clogging of the film is suppressed, and long-term operation becomes easier. Presumably, by _{setting the ratio Ad} / _Au to 0.2 or more, the pressure loss when the raw material liquid passes through the hollow portion of the hollow thread-like forward osmosis membrane is reduced, and the pressure applied from the inside to the outside of the membrane is reduced. It is presumed that it is due to the decrease. Further, when this ratio _Ad / _Au is 10 or less, the water permeability is high and easily maintained. Presumably, by _{setting the ratio Ad} / _Au to 10 or less, when the solvent in the raw material liquid moves to the induction solution via the forward osmosis membrane, the surface of the forward osmosis membrane (in a preferred embodiment of the present invention, the support layer). It is presumed that the retention of the raw material solution on the surface of the above separation active layer) is suppressed, and therefore the osmotic pressure of the raw material solution is maintained low.

The “raw material liquid flow path cross-sectional area of the forward osmosis membrane unit” means the total cross-sectional area of the hollow portion of the hollow thread-like forward osmosis membrane contained in the forward osmosis membrane unit.
In the raw material liquid concentration system of the present embodiment, when three or more forward osmosis membrane units are arranged in series, the ratio _Ad / _Au in the set of two forward osmosis membrane units adjacent to each other is in the above range. It is preferably inside. For example, if the three forward osmosis membrane units are arranged in series, a total of A ₂ of the raw material liquid flow path cross-sectional area of the second forward osmosis membrane unit, the feed liquid passage of the first forward osmosis membrane unit The ratio A ₂ / _{A 1} to the total cross-sectional area _{A 1} is 0.2 or more and 10 or less, and the total cross-sectional area of the raw material liquid flow path of the third forward osmosis membrane unit A ₃ is the second forward osmosis. It is preferable that the ratio A ₃ / A ₂ _{to the total A 2} of the cross-sectional area of the raw material liquid flow path of the membrane unit is 0.2 or more and 10 or less.

The above ratio _Ad / _Au is, for example,
Adjusting the cross-sectional area of the raw material liquid flow path of each forward osmosis membrane unit connected in series;
Placing multiple forward osmosis membrane units connected in parallel on some or all of the forward osmosis membrane units connected in series;
It can be adjusted to a desired value by such means.

When a plurality of forward osmosis membrane units are arranged in series, the degree of concentration is low in the unit on the upstream side of the raw material liquid, and the viscosity of the raw material liquid flowing into the hollow portion of the hollow filament-like forward osmosis membrane is less than 20 cP. However, in the unit on the downstream side of the raw material liquid, the degree of concentration increases, and the viscosity of the raw material liquid may fall within the range of 20 cP or more and 600 cP or less.
In such a case, it is not necessary to control the linear velocity of the raw material solution and the inductive solution in the upstream unit having a low viscosity of the raw material solution. In a unit having a viscosity of the raw material solution of less than 20 cP, highly efficient concentration is possible without controlling the linear velocity of the raw material solution and the inductive solution.
Among a plurality of forward osmosis membrane units arranged in series, in a unit in which the viscosity of the raw material liquid flowing into the hollow portion of the hollow thread-like forward osmosis membrane on the downstream side of the raw material liquid flow is in the range of 20 cP or more and 600 cP or less. By adjusting the viscosities of the raw material solution and the inductive solution within the above ranges, the advantageous effects of the present invention will be exhibited.

When two or more forward osmosis membrane units are arranged in series, one or more raw material liquid feeding pumps may be arranged between the two or more forward osmosis membrane units arranged in series. By arranging the raw material liquid feed pump between the units, the pressure loss when the raw material liquid passes through the hollow portion of the hollow thread-like forward osmosis membrane is reduced, and the pressure applied from the inside to the outside of the membrane can be reduced. Therefore, clogging and deterioration of the film can be suppressed, and long-term operation becomes easier.

The raw material solution concentrating system of the present embodiment may further include an induction solution membrane unit that removes a solvent from the dilution induction solution to obtain a regeneration induction solution.

Hereinafter, the present embodiment will be described with reference to the drawings with reference to non-limiting specific examples.
FIGS. 1 to 17 show schematic views for explaining an example of the raw material liquid concentration system of the present embodiment, which each has a forward osmosis concentration step and optionally an induction solution regeneration step.

In the forward osmosis concentration step of the raw material liquid concentration system of FIG. 1, a forward osmosis membrane unit A having a forward osmosis membrane o and performing a forward osmosis process is used. The internal space of the forward osmosis membrane unit A is divided into two, a raw material liquid side space R and an induction solution side space D, by the forward osmosis membrane o. The raw material liquid a, which is the object to be concentrated, is introduced into the space R on the raw material liquid side of the forward osmosis membrane unit A. On the other hand, the induction solution d is introduced into the induction solution side space D of the forward osmosis membrane unit A.
The raw material liquid a contains a solute and a solvent b. The inducing solution d preferably contains an inducing substance and further contains a solvent b. The osmotic pressure of the inductive solution d is set to be higher than that of the raw material solution a.
Then, when the raw material solution a and the inductive solution d are brought into contact with each other via the forward osmosis membrane o, the solvent b in the raw material liquid a passes through the forward osmosis membrane o using the osmotic pressure difference between the two solutions as a driving force. To move to the induction solution d side. As a result, a concentrated liquid c, which is a concentrated raw material liquid, and a diluted induction solution e, which is a diluted induction solution, can be obtained.

In the raw material liquid concentration system of FIG. 2, the forward osmosis membrane unit A and the forward osmosis membrane unit B are connected in series in the forward osmosis concentration step. The configurations of these two forward osmosis membrane units are the same as those of the forward osmosis membrane unit A in the raw material liquid concentration system of FIG. 1, respectively.
Here, first, the raw material liquid a is introduced into the space R on the raw material liquid side of the forward osmosis membrane unit A. Next, the raw material liquid that has passed through the forward osmosis membrane unit A is introduced into the raw material liquid side space R of the forward osmosis membrane unit B, and is further passed through the forward osmosis membrane unit B to obtain a concentrated liquid c.
The inducing solution d is introduced into the induction solution side space D of the forward osmosis membrane unit B, passes through the forward osmosis membrane unit B to be diluted, and then introduced into the induction solution side space D of the forward osmosis membrane unit A. It passes through the osmotic membrane unit A and is further diluted to obtain a dilution induction solution e.

In the raw material liquid concentration system of FIG. 3, the forward osmosis membrane unit A and the forward osmosis membrane unit B are connected in series as in FIG.
Here, the raw material liquid a is passed through the forward osmosis membrane unit A and the forward osmosis membrane unit B in this order to obtain the concentrated liquid c, which is the same as in FIG.
However, in the raw material solution concentrating system of FIG. 3, the induction solution d is introduced into the induction solution side space D of the forward osmosis membrane unit A and the induction solution side space D of the forward osmosis membrane unit B, respectively, and is introduced from the raw material solution a. A dilution induction solution e diluted by embracing the solvent b is obtained from each of the forward osmosis membrane units A and B.

In the raw material liquid concentration system of FIG. 4, the forward osmosis membrane unit A and the forward osmosis membrane unit B are connected in series as in FIG.
Here, the raw material solution a is passed through the forward osmosis membrane unit A and the forward osmosis membrane unit B in this order to obtain a concentrated solution c, and the induction solution d is passed through the forward osmosis membrane unit B and the forward osmosis membrane unit A. It is the same as in FIG. 2 to pass in order to obtain the dilution induction solution e.
However, in the raw material liquid concentrating system of FIG. 4, the raw material liquid feeding pump is arranged in the raw material liquid flow path between the forward osmosis membrane unit A and the forward osmosis membrane unit B connected in series.
In the raw material liquid concentrating system of FIG. 4, the linear velocity of the raw material liquid passing through the forward osmosis membrane unit can be appropriately controlled by the raw material liquid feeding pump arranged in the raw material liquid flow path.

In the raw material solution concentration system of FIG. 5, the forward osmosis membrane unit A and the forward osmosis membrane unit B are connected in series as in FIG. Passing in the order of B to obtain a concentrated solution c, and passing the inducing solution d through the forward osmosis membrane unit B and the forward osmosis membrane unit A, respectively, and diluting the inducing solution e from each of the two forward osmosis membrane units e. To obtain is the same as in FIG.
However, in the raw material liquid concentrating system of FIG. 5, the raw material liquid feeding pump is arranged in the raw material liquid flow path between the forward osmosis unit A and the forward osmosis membrane unit B connected in series.

The raw material liquid concentration system of FIG. 6 has a forward osmosis concentration step and an induction solution regeneration step.
The configuration and function of the forward osmosis membrane unit A are the same as those of the forward osmosis membrane unit A of the raw material solution concentration system of FIG. The solution d is diluted to obtain a dilution induction solution e. This dilution induction solution e is sent to the mixing mechanism.
The inductive solution regeneration step has an inductive solution concentrating unit and a mixing unit.
In the induction solution concentration unit, a part of the solvent b is removed from the dilution induction solution e to obtain a concentration induction solution f. In the induction solution regeneration unit, a known concentration means such as an evaporation means may be used to remove the solvent from the dilution induction solution d.
The concentrated induction solution f obtained in the induction solution concentration unit is sent to the mixing unit.
Further, the dilution induction solution e obtained in the forward osmosis membrane unit A in the above forward osmosis concentration step is also sent to the mixing unit.
Then, in the mixing mechanism, the concentration-inducing solution f obtained in the induction solution concentration step and the dilution induction solution e obtained in the forward osmosis concentration step are mixed, and the concentration is adjusted as necessary to prepare the induction solution. Will be played. The obtained regeneration-inducing solution may be used as the inducing solution d.
The mixing mechanism may be, for example, a buffer tank.

The raw material liquid concentration system of FIGS. 7 to 10 is a raw material liquid concentration system in which each of the forward osmosis concentration steps of FIGS. 2 to 5 is combined with the same induction solution regeneration step as shown in FIG.

The raw material liquid concentration system of FIG. 11 includes a forward osmosis concentration step and an induction solution regeneration step, and the forward osmosis concentration step includes a circulation mechanism.
In the raw material liquid concentration system of FIG. 11, the forward osmosis concentration step is the same as the forward osmosis concentration step of the raw material liquid concentration system of FIG. 6 except that the circulation mechanism is included, and the induction solution regeneration step is the raw material liquid concentration of FIG. It is the same as the induction solution regeneration step of the system.
The circulation mechanism has a function of reintroducing the concentrated liquid obtained in the forward osmosis membrane unit A into the space R on the raw material liquid side of the forward osmosis membrane unit A as a raw material liquid. In this case, the number of times the raw material liquid is passed through the forward osmosis membrane unit A (that is, the number of times the concentrated liquid obtained in the forward osmosis membrane unit A is reintroduced as the raw material liquid in the forward osmosis membrane unit A) is arbitrary. Reintroduction a predetermined number of times gives a highly concentrated concentrate c.

The raw material liquid concentrating system of FIG. 12 is a raw material liquid concentrating system in which the raw material liquid concentrating system of FIG. 7 is combined with the same circulation mechanism as shown in FIG.

The raw material liquid concentration system of FIG. 13 includes a forward osmosis concentration step and an induction solution regeneration step.
In the raw material liquid concentration system of FIG. 13, the forward osmosis membrane unit A, the forward osmosis membrane unit B, and the forward osmosis membrane unit C are connected in series in the forward osmosis concentration step. The configurations of these three forward osmosis membrane units are the same as those of the forward osmosis membrane unit A in the raw material liquid concentration system of FIG. 1, respectively. The forward osmosis concentration step of the raw material liquid concentration system of FIG. 13 further has a circulation mechanism.

In the raw material liquid concentrating system of FIG. 13, first, the raw material liquid a is introduced into the raw material liquid side space R of the forward osmosis membrane unit A and passed through the forward osmosis membrane unit A. Next, the raw material liquid that has passed through the forward osmosis membrane unit A is introduced into the space R on the raw material liquid side of the forward osmosis membrane unit B, and is passed through the forward osmosis membrane unit B. Further, the raw material liquid that has passed through the forward osmosis membrane unit B is introduced into the space R on the raw material liquid side of the forward osmosis membrane unit C, and is passed through the forward osmosis membrane unit C.
The raw material liquid that has passed through the forward osmosis membrane unit C is reintroduced as a raw material liquid into the space R on the raw material liquid side of the forward osmosis membrane unit A by the circulation mechanism. The number of times the raw material liquid is passed through the forward osmosis membrane units A to C (that is, the number of times the concentrated liquid obtained by the forward osmosis membrane units A to C is reintroduced as the raw material liquid in the forward osmosis membrane units A to C) is arbitrary. be. Reintroduction a predetermined number of times gives a highly concentrated concentrate c.

The inducing solution d is introduced into the inducing solution side space D of the forward osmosis membrane unit C, passes through the forward osmosis membrane unit C to be diluted, and then introduced into the inducing solution side space D of the forward osmosis membrane unit B. It passes through the osmosis membrane unit B and is further diluted, introduced into the induction solution side space D of the forward osmosis membrane unit A, passes through the forward osmosis membrane unit A and is additionally diluted to obtain a dilution induction solution e. ..

The inductive solution regeneration step in the raw material liquid concentration system of FIG. 13 has the same function as the inductive solution regeneration step in the raw material liquid concentration system of FIG.

The raw material liquid concentrating system of FIG. 14 is a raw material liquid concentrating system in which a circulation mechanism is added to the raw material liquid concentrating system of FIG.

The raw material liquid concentration system of FIG. 15 includes a forward osmosis concentration step and an induction solution regeneration step. The forward osmosis concentration step involves a circulation mechanism.
Here, the concentrated liquid obtained by passing the raw material liquid a through the forward osmosis membrane unit A, the forward osmosis membrane unit B, and the forward osmosis membrane unit C in this order is reintroduced into the forward osmosis membrane unit A by a circulation mechanism. It is the same as the raw material liquid concentration system of FIG. 13 that a highly concentrated concentrated liquid c can be obtained by reintroduction and circulation a predetermined number of times.
However, in the raw material solution concentration system of FIG. 15, the induction solution d is the induction solution side space D of the forward osmosis membrane unit A, the induction solution side space D of the forward osmosis membrane unit B, and the induction solution side of the forward osmosis membrane unit C. A dilution-inducing solution e, which is introduced into the space D and diluted by embracing the solvent b from the raw material solution a, is obtained from each of the forward osmosis membrane units A, B, and C.

The raw material liquid concentrating system of FIGS. 16 and 17 is a raw material liquid concentrating system in which the raw material liquid concentrating system of FIGS. 9 and 10 is combined with the same circulation mechanism as shown in FIG. 12, respectively.

In the raw material liquid concentration system shown in FIGS. 1 to 17, the raw material liquid a and the induction solution d are countercurrent in the forward osmosis concentration step, but parallel flow may be used.
Further, the forward osmosis treatment in the forward osmosis concentration step may be performed by a total amount filtration method or a cross-flow filtration method, but the cross-flow filtration method is preferable from the viewpoint of filtration flow velocity and suppression of membrane contamination.

Further, in FIGS. 6 to 17, the concentrated induction solution f obtained by the induction solution concentration unit in the induction solution regeneration step may be directly used as the induction solution d. In this case, it is preferable that the concentration of the concentration-inducing solution f is controlled to be substantially the same as the concentration of the induction solution d.

<< Method of concentrating raw material liquid >>
The method for concentrating the raw material liquid of the present embodiment is as described above.
A raw material solution containing a solvent and a solute and an inducing solution containing an inducing substance are brought into contact with each other via a normal osmotic membrane, and the solvent in the raw material solution is moved into the inducing solution to obtain a dilution inducing solution. A method for concentrating a raw material solution, which comprises a step of concentrating the raw material solution while obtaining the raw material solution.
The forward osmosis membrane has a hollow thread shape and is in the form of a hollow thread.
The method for concentrating the raw material liquid includes a step of circulating the raw material liquid through the hollow portion of the hollow thread-shaped forward osmosis membrane and circulating the induction solution outside the hollow thread-shaped forward osmosis membrane.
When the viscosity of the raw material liquid flowing into the hollow portion of the hollow thread-like forward osmosis membrane is 20 cP or more and 600 cP or less, the linear velocity of the raw material liquid flowing into the hollow portion of the hollow thread-like forward osmosis membrane is set to 0. 1 cm / s or more and 5.0 cm / s or less,
This is a method for concentrating the raw material liquid.
According to another embodiment of the present embodiment, in the raw material liquid concentration step, the linear velocity of the induction solution flowing into the outside of the forward osmosis membrane is 0.1 cm / s or more and 10 cm / s or less.
In the raw material liquid concentration step, the linear velocity control of the raw material solution and the linear velocity control of the inductive solution may be performed in an overlapping manner.

When the viscosity of the raw material liquid flowing into the hollow portion of the hollow thread-like forward osmosis membrane is 20 cP or more and 600 cP or less, the linear velocity of the raw material liquid flowing into the hollow portion of the hollow thread-shaped forward osmosis membrane is 0.9 cm / It is preferably s or more and 3.5 cm / s or less.

The induction solution used in the method for concentrating the raw material solution of the present invention is preferably an inorganic salt solution containing a divalent cation;
The positive osmotic membrane consists of polyethersulfone, polysulfone, polyketone, polyetheretherketone, polyphenylene ether, polyvinylidene fluoride, polyacrylonitrile, polyimine, polyimide, polybenzoxazole, polybenzoimidazole, sulfonated tetrafluoroethylene, and polyamide. It is preferable that the film has a thin film layer containing at least one selected from the group as a main component.

In the method for concentrating the raw material liquid of the present embodiment, the raw material liquid concentrating step may be performed in two or more steps in series.
In this case, the consecutive two-step starting solution concentration step is carried out of the two or more stages of the raw material solution concentration step, the raw material liquid flow path cross-sectional area A _d of the forward osmosis membrane used in the subsequent stage of the raw material solution concentration step, the ratio a _{d /} a _u for feed liquid flow path cross-sectional area a _u of the preceding forward osmosis membrane, preferably 0.2 to 10, more preferably 1 to 8.

In the raw material liquid concentrating step performed in two or more steps in series, one raw material liquid feeding pump is used to supply the raw material liquid concentrated in the raw material liquid concentrating step in the previous stage as the raw material liquid in the raw material liquid concentrating step in the subsequent stage. The above may be used.

Further, it is also an example of a preferable embodiment of the present embodiment that the concentrated liquid obtained by the method for concentrating the raw material liquid of the present invention is further concentrated by subjecting it to another additional concentrating method to obtain a final product. ..

In the method for concentrating the raw material solution of the present embodiment, the dilution inducing solution obtained in the raw material solution concentrating step may be regenerated into the inducing solution and reused.
As the regeneration and reuse of the dilution induction solution, specifically, for example,
Perform an induction solution concentration step of removing the solvent from the dilution induction solution to obtain a regeneration induction solution, and use the concentration induction solution obtained in this induction solution concentration step as the induction solution;
The concentration-inducing solution obtained in the induction solution concentration step and the induction solution concentration step, in which the solvent is removed from the induction solution to obtain a concentration induction solution, and the dilution induction solution obtained in the raw material solution concentration step are mixed and mixed. Perform the step and use the mixed solution obtained in the mixing step as an inducing solution;
And so on.
The induction solution concentration step in the above method can be performed by, for example, an evaporation means.

The description of the raw material liquid concentrating system described above can be used as it is, or after appropriate changes or replacements by those skilled in the art, as a description of each element of the raw material liquid concentrating method of the present embodiment.
The method for concentrating the raw material liquid of the present embodiment can be performed using, for example, the raw material liquid concentrating system of the present embodiment.

<< Method of concentrating raw material liquid including cleaning process of forward osmosis membrane >>
If the method for concentrating the raw material liquid of the present embodiment is continued for a long time, the forward osmosis membrane may become dirty due to the accumulation of deposits and the amount of water permeation may decrease. In particular, when the raw material liquid has a high concentration, the forward osmosis membrane tends to be significantly contaminated. Therefore, it is desirable to wash the forward osmosis membrane to return the water permeability to the initial value and then reuse it. Is done.
Another aspect of the present invention provides a method for concentrating a raw material solution, which comprises a step of cleaning the forward osmosis membrane.
This embodiment is described in the method for concentrating the raw material liquid of the present embodiment.
The first cleaning step of cleaning the forward osmosis membrane by bringing the raw material solution and the diluted solution or solvent of the induction solution whose osmotic pressure is adjusted to be lower than that of the raw material solution into contact with each other through the forward osmosis membrane. It is a method to have further.
The method for concentrating the raw material liquid of this embodiment may further include a second step of cleaning the forward osmosis membrane by bringing a solvent into contact with both sides of the forward osmosis membrane after the first step.

<First cleaning process>
In the first cleaning step in the cleaning method of the raw material liquid concentration system of the present embodiment, the raw material liquid and the diluted solution or solvent of the induction solution whose osmotic pressure is adjusted to be lower than that of the raw material liquid are passed through a forward osmosis membrane. This is a step of cleaning the forward osmosis membrane by bringing them into contact with each other.
Instead of the inducing solution, a diluted solution of the inducing solution whose osmotic pressure is adjusted to be lower than that of the raw material solution or the solvent itself is used, and when this and the raw material solution are brought into contact with each other through a forward osmosis membrane, the osmotic pressure becomes the raw material solution. Since the value is higher on the side, the solvent moves from the diluting solution or the solvent of the induction solution to the raw material solution by using the osmotic pressure difference as a driving force. That is, the forward osmosis membrane is efficiently washed by passing the solvent in the direction opposite to that during the concentration operation in the thickness direction of the forward osmosis membrane and washing out the deposits existing in the pores of the forward osmosis membrane, for example. It becomes possible to do.
The diluted solution or solvent of the inducing solution and the raw material solution to be brought into contact with the forward osmosis membrane may or may not be flowed independently. When both of these flow, it may be convection or convection.

<Second cleaning process>
The second cleaning step in the cleaning method of the raw material liquid concentration system of the present embodiment is a step of cleaning the forward osmosis membrane by bringing a solvent into contact with both sides of the forward osmosis membrane.
In this second cleaning step, the deposits that have been washed out from the pores of the forward osmosis membrane and adhered to the surface of the forward osmosis membrane or its vicinity can be washed away by the first cleaning step, for example. .. Therefore, this second cleaning step is preferably performed after the first cleaning step.
The solvent that comes into contact with the forward osmosis membrane may or may not flow independently on both sides. When both solvents on both sides of the forward osmosis membrane are allowed to flow, they may be countercurrent or convection.

<< Method of concentrating raw material liquid including inspection process of forward osmosis membrane >>
In the method for concentrating the raw material liquid of the present embodiment, an inspection step can be performed in order to confirm the performance of the forward osmosis membrane.
Therefore, another aspect of the present invention provides a method for concentrating a raw material solution, which comprises a step of inspecting a forward osmosis membrane.
The method for concentrating the raw material liquid of the present embodiment is
Using the solvent itself instead of the raw material liquid,
It is included in the step of operating the solvent and the inducing solution in contact with each other through the forward osmosis membrane, moving the solvent into the inducing solution, and measuring the permeation flow velocity thereof.
According to the method for concentrating the raw material liquid of the present embodiment, the change in the performance of the forward osmosis membrane can be easily and surely confirmed by the inspection step of the forward osmosis membrane.

Therefore, when the raw material liquid is continuously concentrated for a long period of time by the method for concentrating the raw material liquid of the present embodiment, for example, the forward osmosis membrane is periodically washed, and after the washing of the forward osmosis membrane, the forward osmosis membrane is washed. , The inspection of the present embodiment can be performed to confirm the degree of performance recovery of the forward osmosis membrane, and it can be easily determined whether or not the concentration operation can be continued.
For example, the cleaning and inspection of the present embodiment are performed every time a certain period of time elapses after the start of operation, and the operation is terminated when the permeation flow velocity drops to, for example, 80% or less of the previous cleaning and inspection. Operation management such as is conceivable.

≪Each element of the method of concentrating the raw material liquid≫
Next, each element constituting the method for concentrating the raw material liquid of the present embodiment will be described in detail.
[Raw material liquid]
The raw material liquid is a fluid composed of a solvent-containing article containing a solute and a solvent. The solvent-containing article constituting this raw material liquid may be a solution or an emulsion, and examples thereof include foods, cosmetics, pharmaceuticals, pharmaceutical raw materials, seawater, and accompanying water discharged from gas fields and oil fields. be able to.
According to the system of the present embodiment, the solvent-containing articles constituting the raw material liquid can be efficiently concentrated by controlling the linear velocity of the raw material liquid and the inductive solution according to the viscosity of the raw material liquid. Moreover, in the system of the present embodiment, the raw material liquid can be concentrated without requiring heating of the raw material liquid.
Therefore, when the system of the present invention is applied to the concentration of foods, it is possible to efficiently obtain concentrated foods in which the components in the raw material liquid are not deteriorated and the loss of aroma components is small.

Therefore, the solvent-containing article constituting the raw material liquid applied to the present embodiment is preferably a food product. More preferably, as food products, for example, coffee extract, juice (eg, orange juice, tomato juice, etc.), fruit juice (eg, fruit juice such as apple, grape, orange, grapefruit, lemon, etc.), dairy products (eg, lactic acid bacteria). Beverages, raw milk, etc.), juice (for example, kelp juice, eel juice, etc.), tea extract (for example, green tea, medium-grade green tea), roasted green tea, refined green tea. ), Covered tea, extract such as sweet tea), seasonings (eg, soy sauce, Worcester sauce, spice solution, etc.), perfume emulsions (eg, vanilla essence, strawberry essence, etc.) ), Food oil emulsions (eg emulsions such as rapeseed oil, sunflower oil, red flower oil, corn oil), sugar-containing sweeteners (eg maple sap, honey, coconut liquid germ milk, sugar cane sugar solution, Rakan fruit juice, etc.) ) And so on.

Examples of sugars in sweeteners include monosaccharides (eg, glucose, fructose, galactose, mannose, ribose, deoxyribose, etc.), disaccharides (eg, maltose, sucrose, lactose, etc.), sugar chains (eg, glucose, etc.). In addition to galactose, mannose, fucose, xylose, glucuronic acid, isulonic acid and the like; saccharide derivatives such as N-acetylglucosamine, N-acetylgalactosamine and N-acetylneuraminic acid can be mentioned.
The raw material liquid that is a food product applied to the present embodiment is preferably a raw material liquid containing a solute containing sugar and a liquid medium, and more preferably maple sap or coconut liquid endosperm.
The liquid medium contained in these raw material liquids dissolves or disperses solutes in the raw material liquids. In a typical embodiment, the liquid medium is water.
The raw material liquid may be a fluid, and in addition to the solution, for example, a mixture such as an emulsion is also included.
When the method for concentrating the raw material liquid of the present embodiment is applied to such a raw material liquid, it has a high sugar content (Brix value), contains many components useful for maintaining and improving health, and has light transmittance. High, concentrates can be obtained.

Maple sap is generally collected from maple trees during the period of the year when the sugar content is the highest and the temperature difference between day and night is large (for example, March to April in the Northern Hemisphere). Normally, sap contains only 2-4% by mass of sugar. Therefore, about 40 L of sap is required to make 1 L of syrup.

In one aspect, maple sap is used as the raw material sap and maple syrup is obtained as the concentrate.
The quality of maple syrup is graded according to unified standards in Canada and the United States. In general, the closer the sap is collected to the beginning of the season, the lighter the color of the sap, and the resulting maple syrup has a delicate taste and high light transmittance. Maple syrup with high light transmittance is called "extra light". On the other hand, those with low light transmittance are called "dark". The higher the light transmittance of maple syrup, the better the quality.
The sugar content (Brix value) of maple syrup is generally 66.5%, which is equivalent to that of granulated sugar, white sugar and the like. In addition, maple syrup has a lower calorie content than, for example, white sugar honey, and tends to have a higher content of minerals such as calcium and potassium than other sweeteners.

Coconut liquid endosperm refers to translucent liquid endosperm contained in immature coconut fruit. Coconut liquid endosperm is rich in minerals, has a mineral composition close to that of human body fluids, and has an osmotic pressure almost the same as that of the human body, so that it can be a natural nutrient-rich hydration material.
Among the abundant minerals of coconut liquid endosperm, magnesium and potassium are known to be effective in eliminating swelling and activating metabolic enzymes.
Even in coconut liquid endosperm, the higher the light transmittance, the more delicate the taste and the better the quality.

In one aspect, the Brix value of the concentrate (ie, the value of sugar content measured by a Brix meter) is 50 or greater. The Brix value before concentration (that is, the raw material liquid) is about 1 to 5. When such a raw material liquid having a low sugar content is concentrated in a concentrated liquid having a Brix value of 50, the concentration rate is about 10 to about 50 times. That is, a Brix value of 50 or more of the concentrated solution is an index of the concentrated solution having a high concentration rate. The Brix value of the concentrated solution is preferably 50 or more or 60 or more from the viewpoint of obtaining a concentrated solution having a high concentration rate. The upper limit of the Brix value of the concentrate is not particularly limited, but from the viewpoint of ease of production of the concentrate, it may be, for example, 75 or less or 70 or less.
In one aspect, the concentrate of the present disclosure has a high light transmittance even at a high concentration of Brix value of 50 or more. This high light transmittance is an index that the transmittance of the raw material liquid before concentration is well maintained.

The absorbance of the concentrate at 450 nm in UV-visible spectroscopy is preferable from the viewpoint that the concentrate contains many healthy components that are effective in eliminating swelling and activating metabolic enzymes. It may be 0.1 or more, more preferably 0.2 or more. Further, the absorbance is preferably 1.0 or less, and may be 0.8 or less, from the viewpoint of high quality of the concentrated liquid (particularly, the flavor is delicate). The light transmittance of the concentrated liquid of the present disclosure is an index indicating that the transmittance and flavor before concentration (that is, in the raw material liquid) are well maintained.
Such concentrates have not been known conventionally.

Therefore, from another point of view of the present invention,
A food product that is a concentrate of a solute containing sugar and a raw material liquid containing a liquid medium.
The concentrate is
Brix value is 50 or more and
The absorbance at 450 nm in ultraviolet-visible spectroscopy is 0.1 or more and 1.0 or less.
Groceries are provided.

[Solute]
The solute refers to a substance selected from an inorganic compound and an organic compound, and is preferably dissolved in a solvent.
The solute may be liquid or solid.
[solvent]
The solvent is a liquid. The solvent can be any inorganic or organic solvent, preferably dissolving the solute. The solvent exists as a liquid in the raw material liquid. The solvent is often water.

[Concentrated raw material liquid]
In the concentrated raw material liquid, at least a part of the solvent is selectively separated and removed from the raw material liquid by passing the raw material liquid through a forward osmosis concentration step, and the components (solutes) in the raw material are maintained. can get. In the method for concentrating the raw material liquid of the present embodiment, the amount or ratio of the solvent separated from the raw material liquid can be arbitrarily controlled.
According to the step of forward osmosis concentration in the present embodiment, it is possible to concentrate to near the saturation concentration of the raw material solution as long as the osmotic pressure of the concentrated raw material solution does not exceed the osmotic pressure of the induction solution.
The forward osmosis concentration step of the present embodiment is a forward osmosis process. Therefore, it is possible to obtain a high concentration ratio while maintaining a high level of raw material liquid components. Further, since an arbitrary concentration ratio can be obtained by changing the induction solution, there are various types of raw material liquids to which the raw material liquid concentration system of the present embodiment can be applied, and substantially any liquid can be concentrated. It is possible. Therefore, according to the present embodiment, a high-quality concentrated raw material liquid can be obtained with high efficiency even in the case of a raw material liquid to which the prior art has been impossible or difficult to apply.
In particular, this embodiment is suitable as a method for concentrating a raw material liquid for a food manufacturing process. As described above, when the method for concentrating the raw material liquid of the present embodiment is applied to the concentration of food or the raw material thereof, it is possible to concentrate the food while maintaining the quality of the food.

As described above, the method for concentrating the raw material liquid of the present embodiment is effective for obtaining a food product as a concentrated liquid using maple sap or coconut liquid endosperm as the raw material liquid.

[Induction solution]
The inducing solution is a solution containing an inducing substance. The inductive solution is preferably a fluid that has a higher osmotic pressure than the raw material solution and does not significantly denature the forward osmotic membrane.
(Inducible substance)
The inducer may be any substance that can give an osmotic pressure higher than that of the raw material solution when dissolved in a solvent, and a substance having high solubility in water is particularly preferable in terms of ease of osmotic pressure adjustment. Examples of the inducer that can be used in this embodiment include salts, sugars, alcohols, and polymers. In one embodiment, the inducer may be one or more selected from the group consisting of salts, sugars, alcohols, and polymers.
Examples of the inorganic salt include sodium chloride, potassium chloride, magnesium chloride, calcium chloride, sodium sulfate, magnesium sulfate, sodium thiosulfate, sodium sulfite, ammonium chloride, ammonium sulfate, ammonium carbonate and the like;
Examples of sugars include general sugars such as sucrose, fructose, and glucose; and special sugars such as oligosaccharides and rare sugars;
Examples of the alcohol include monoalcohols such as methanol, ethanol, 1-propanol and 2-propanol; and glycols such as ethylene glycol and propylene glycol.
Examples of the polymer include polymers such as polyethylene oxide and polypropylene oxide, and copolymers thereof.
Among the above-mentioned inducers, the inducer is preferably a salt, particularly an inorganic salt, in that it has a high osmotic pressure.

The concentration of the inducing substance in the inducing solution is set so that the osmotic pressure of the inducing solution is higher than the osmotic pressure of the raw material solution. The osmotic pressure of the inductive solution may fluctuate within that range as long as it is higher than the osmotic pressure of the raw material solution.
Examples of the method for determining the osmotic pressure difference between the two liquids include the following methods.
(1) When two liquids are mixed and then separated into two phases: A method of determining that the osmotic pressure of the liquid with the larger volume is higher after the two-phase separation, or
(2) When the two liquids are mixed and not separated into two phases: A method in which the two liquids are brought into contact with each other through a forward osmosis membrane, and the osmotic pressure of the liquid whose volume has increased after a certain period of time is judged to be high. The fixed time at this time depends on the osmotic pressure difference, but is generally in the range of several minutes to several hours.

(Solvent of induction solution)
The solvent that may be contained in the inductive solution may be water, ethanol, or the like. However, the solvent of the induction solution is preferably the same type as the solvent to be separated and removed from the raw material solution, and from this viewpoint, water is preferable.

[Forward osmosis membrane]
The forward osmosis membrane is a membrane having a function of allowing a solvent to permeate but not a solute.
The forward osmosis membrane may be composed of a single layer, or may be a membrane having a support layer and a separation active layer on the support layer.
The shape of the forward osmosis membrane in this embodiment is a hollow thread. When a hollow thread-shaped forward osmosis membrane is used, the membrane area per unit volume is large, and high-concentration concentration can be efficiently performed.
When the forward osmosis membrane is in the form of a hollow thread, it is easy to clean the forward osmosis membrane by allowing the raw material liquid to flow through the hollow portion of the hollow thread-like forward osmosis membrane and the inducing solution to flow outside the hollow thread-like forward osmosis membrane. Therefore, it is preferable.
As a hollow filamentous positive osmotic film, since it has a high blocking rate of inducers, polyethersulfone, polysulfone, polyketone, polyether ether ketone, polyphenylene ether, polyvinylidene fluoride, polyacrylonitrile, polyimine, polyimide, polybenzoxazole, A film having a thin film layer containing at least one selected from the group consisting of polybenzoimidazole, sulfonated tetrafluoroethylene, perfluorosulfonic acid polymer, and polyamide as a main component is preferable.

Polyamides can be formed by interfacial polymerization of polyfunctional acid halides and polyfunctional aromatic amines.
A polyfunctional aromatic acid halide is an aromatic acid halide compound having two or more acid halide groups in one molecule. Specifically, for example, trimesic acid halide, trimellitic acid halide, isophthalic acid halide, terephthalic acid halide, pyromellitic acid halide, benzophenone tetracarboxylic acid halide, biphenyldicarboxylic acid halide, naphthalenedicarboxylic acid halide, pyridinedicarboxylic acid halide, etc. Examples thereof include benzenedisulfonic acid halide, which can be used alone or in admixture thereof. Examples of the halide ion in these aromatic acid halide compounds include chloride ion, bromide ion, and iodide ion.
In the present embodiment, particularly trimesic acid chloride alone, a mixture of trimesic acid chloride and isophthalic acid chloride, or a mixture of trimesic acid chloride and terephthalic acid chloride is preferably used.

The polyfunctional aromatic amine is an aromatic amino compound having two or more amino groups in one molecule. Specifically, for example, m-phenylenediamine, p-phenylenediamine, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3 , 3'-diaminodiphenylamine, 3,5-diaminobenzoic acid, 4,4'-diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfone, 3,4′-diaminodiphenylsulfone, 1,3,5-triamino Benzene, 1,5-diaminonaphthalene and the like can be mentioned, and these can be used alone or in combination thereof.
In this embodiment, in particular, one or more selected from m-phenylenediamine and p-phenylenediamine are preferably used.
Interfacial polymerization of polyfunctional acid halides and polyfunctional aromatic amines can be carried out according to routine methods.

A perfluorosulfonic acid polymer generally refers to a polymer having a side chain having a sulfonic acid in a main chain skeleton in which a part or all of hydrogen is replaced with fluorine. Perfluorosulfonic acid polymers are used, for example, in chemically stable cation exchange resins, salt electrolysis, polymer electrolyte fuel cells, water electrolysis or various sensors as ion selective permeable membranes, such as Nafion (registered). (Trademark) (DuPont), Aciplex (registered trademark) (Asahi Kasei Co., Ltd.), Flemion (registered trademark) (AGC Co., Ltd.), etc. Some are listed.

The chemical structure of the perfluorosulfonic acid polymer is not particularly limited, but is typically the following structural formula (1);

{In formula (1), _{_{_{Y, - (CF 2 -CF (CF}}} 3) -O-) m - (CF 2) it is a monovalent group represented by n -SO ₃ H; x is 0 It is a number from .06 to 0.5; m is an integer from 0 to 2, and n is an integer from 1 to 6. } Can be mentioned. Incidentally, _"(CF 2 -CF _2)" units and _"(CF 2 -CF (OY))" sequence of units has been described for convenience block structure in formula (1), be a block It may be random, random, or a combination thereof.

In this embodiment, a hollow thread-like forward osmosis membrane is used. In the present embodiment, it is particularly preferable to use a composite hollow fiber having a separation active layer made of a polymer thin film on the inner surface of the hollow fiber-like porous support membrane.
As the support film, for example, it is preferable to use a film composed of a component selected from polyethersulfone, polysulfone, polyketone, polyether ether ketone, polyphenylene ether, polyvinylidene fluoride, polyacrylonitrile, and the like.
As the separation active layer, for example, it is preferable to use a layer composed of a component selected from polyimine, polyimide, polybenzoxazole, polybenzimidazole, sulfonated tetrafluoroethylene, perfluorosulfonic acid polymer, polyamide and the like. ..

The outer diameter of the hollow fiber membrane constituting the forward osmosis membrane is, for example, 300 μm or more and 5,000 μm or less, preferably 350 μm or more and 4,000 μm or less, and the inner diameter of the hollow fiber membrane is, for example, 200 μm or more and 4,000 μm or less. It is preferably 500 μm or more and 1,500 μm or less. When the inner diameter of the hollow fiber membrane is 200 μm or more, the pressure in the hollow fiber during the circulation operation becomes relatively small, and the contact area of the raw material component becomes small. Therefore, the solute contained in the raw material liquid is less likely to adhere to the film surface. Such an effect is more easily obtained when the inner diameter of the hollow fiber membrane is 500 μm or more. On the other hand, when the inner diameter of the hollow fiber membrane is 4,000 μm or less, the contact area of the raw material components is not appropriately large, so that the solvent separation efficiency is not easily impaired.
As the forward osmosis membrane, it is preferable to use one in the form of a forward osmosis membrane module in which a thread bundle composed of a plurality of hollow filamentous forward osmosis membranes is preferably housed in a suitable housing.

The permeation flux of the forward osmosis membrane with respect to the solvent ^{is preferably 1.0 L / (m 2} × h) or more. Although the reason is not clear, if the initial permeation flux is 1.0 L / (m ² × h) or more, it becomes easy to prevent the solvent separation efficiency from being impaired. The permeation flow rate is more preferably 3.0 L / (m ² × hr) or more.
The permeated flux for the solvent in the present specification means the amount of the solvent passing through the forward osmosis membrane, which is allocated per unit area of the forward osmosis membrane and per unit time, and is defined by the following formula (1). ).
F = L / (M × H) (1)
Here, F is the permeated flux (L / (m ² × hr)) for the solvent, L is the amount of permeated solvent (L), and M is the surface area (m ² ) of the forward osmosis membrane. Yes, H is the time (h).
The permeated flux when the solvent is water is commonly referred to as the "permeability".

[Introduction of raw material solution and induction solution into the forward osmosis membrane unit]
The raw material liquid to be concentrated is introduced into the raw material liquid side space of the forward osmosis membrane unit, and the inductive solution is introduced into the inductive solution side space. The directions of these flows may be countercurrent or parallel.

[Temperature of raw material solution and induction solution]
In the forward osmosis concentration step of the method for concentrating the raw material liquid of the present embodiment, the temperature of the raw material liquid introduced into the space on the raw material liquid side of the forward osmosis membrane unit is preferably 3 ° C. or higher and 60 ° C. or lower, more preferably 5. It is ℃ or more and 50 ℃ or less. When the temperature of the raw material liquid is 3 ° C. or higher, it is easy to avoid slowing the permeation flow rate, and when the temperature is 60 ° C. or lower, it is easy to avoid denaturation of the components in the raw material liquid.
The temperature of the induction solution introduced into the space on the induction solution side of the forward osmosis membrane unit is preferably 5 ° C. or higher and 60 ° C. or lower, and more preferably 10 ° C. or higher and 50 ° C. or lower. When the temperature of the inducing solution is 5 ° C. or higher or 60 ° C. or lower, it becomes easy to avoid a large amount of the inducing substance moving from the inducing solution to the raw material solution through the forward osmosis membrane.
As a heat source for heating the raw material liquid and the inductive solution, for example, a heat exchanger can be used, or exhaust heat from an industrial process or the like can be used. It is preferable to use exhaust heat as a heat source because the amount of energy consumed can be reduced.

[Induced solution regeneration process]
In the method for concentrating the raw material liquid of the present embodiment, the induction solution regeneration step arbitrarily adopted includes, for example, the following two viewpoints.
The first aspect is an inductive solution regeneration step having the following steps:
The induction solution regeneration step of removing the solvent from the dilution induction solution to obtain a regeneration induction solution which is a concentrate of the dilution induction solution; and the induction solution reuse step of reusing the obtained regeneration induction solution as an induction solution. ..
A second aspect is an inductive solution regeneration step having the following steps:
The induction solution concentration step, in which the solvent is removed from the induction solution to obtain a concentration induction solution that is a concentrate of the induction solution;
Mixing step of mixing the obtained concentration-inducing solution and dilution-inducing solution to obtain a mixture (regeneration-inducing solution); and reusing the obtained regeneration-inducing solution as an inducing solution, inducing solution reuse step.

Removal of the solvent from the dilution induction solution or induction solution in the induction solution regeneration step or the induction solution concentration step may be carried out by, for example, evaporation means. As the evaporation means, for example, a distillation process, a forward osmosis process, a membrane distillation process or the like can be used.
In the distillation process, a dilution induction solution or an induction solution is adjusted to a predetermined temperature and then fed into a distillation tower to obtain a solvent from the top of the column, and the solvent is removed from the bottom of the column to concentrate the dilution induction. It is a process of obtaining a regeneration-inducing solution, which is a solution, or a concentration-inducing solution, which is a concentrated induction solution from which a solvent has been removed.
The forward osmosis process is a process in which a dilution-inducing solution or an inducing solution is circulated in contact with the forward osmosis membrane so that the solvent contained in the dilution-inducing solution or the inducing solution is removed through the forward osmosis membrane. It is a process of obtaining a solvent and a regeneration-inducing solution or a concentration-inducing solution.
In the membrane distillation process, a membrane unit having a separation chamber divided into a liquid phase portion and a gas phase portion by a semipermeable membrane is used. By introducing a dilution induction solution or an induction solution into the liquid phase portion of the membrane unit for membrane distillation and reducing the pressure in the gas phase portion, the solvent contained in the dilution induction solution or the induction solution can be removed from the liquid phase portion. It passes through the semitransparent film and moves to the gas phase part of reduced pressure. Thereby, the solvent can be removed from the dilution induction solution or the induction solution to obtain the regeneration induction solution or the concentration induction solution.

In the induction solution regeneration step or the induction solution concentration step, it is preferable to use a forward osmosis process using a forward osmosis membrane or a membrane distillation process using a semipermeable membrane because of the small equipment size, and a solvent from the dilution induction solution or the induction solution. It is more preferable to use a membrane distillation process using a semipermeable membrane in that the movement of the inducer to the substance can be suppressed.
The elements used in the membrane distillation process will be described below.

[Semipermeable membrane of membrane distillation process]
Examples of the shape of the semipermeable membrane used in the membrane distillation process include a hollow fiber membrane, a flat membrane, and a spiral membrane.
The flat membrane-like semipermeable membrane may be composed of, for example, a single layer, or may have a support layer and a separation active layer on the support layer. The hollow thread-like semipermeable membrane may be, for example, a hollow thread composed of a single layer, a hollow thread-like support layer, an outer surface or an inner surface of the support layer, or both surfaces thereof. It may have the above separation active layer.
The material of the support layer and the separation active layer in the semipermeable membrane may be composed of any material selected from the materials exemplified above for the forward osmosis membrane in the forward osmosis concentration step, respectively.
The permeation flux of the semipermeable membrane with respect to the solvent ^{is preferably 1 L / (m 2} × hr) or more and 200 L / (m ² × hr) or less. If the permeated flux is 1 L / (m ² x hr) or more, it becomes easy to avoid impairing the efficient separation of the solvent, and if it is 200 L / (m ² x hr) or less, the derived solution is used. It becomes easy to avoid an increase in the amount of the inducer that passes through the semipermeable membrane and moves to the solvent.
This permeation flux is defined in the same way as the permeation flux for the solvent of the forward osmosis membrane in the forward osmosis concentration step.

[Temperature of dilution induction solution or induction solution introduced into the membrane distillation process]
It is preferable that the temperature of the dilution induction solution e or the induction solution is adjusted in the range of 20 ° C. or higher and 90 ° C. or lower before being introduced into the liquid phase portion. When this temperature is 20 ° C. or higher, it becomes easy to avoid impairing the efficiency of solvent separation by membrane distillation, and when it is 90 ° C. or lower, the inducing substance contained in the dilution inducing solution or the inducing solution stream is half. It becomes easy to suppress the amount of transfer to the solvent through the permeable membrane.
As a heat source for heating the dilution induction solution or the induction solution, for example, a heat exchanger can be used, or exhaust heat from an industrial process or the like can be used. It is preferable to use exhaust heat as a heat source because the amount of energy consumed can be reduced.

[Phase part in membrane distillation process]
The gas phase portion of the membrane unit for membrane distillation used in the membrane distillation process is preferably depressurized to a predetermined pressure. The pressure of the gas phase portion may be appropriately set according to the scale of the apparatus, the concentration of the induction solution, the production rate of the desired solvent, etc., but is preferably 0.1 kPa or more and 80 kPa or less, and is preferably 1 kPa or more. It is more preferably 50 kPa or less.
Examples of the decompression device for depressurizing the gas phase portion of the membrane unit for membrane distillation include a diaphragm vacuum pump, a dry pump, an oil rotary vacuum pump, an ejector, and an aspirator.

[Products obtained in the induction solution regeneration process]
According to the induction solution regeneration step of the present embodiment, the solvent is separated from the dilution induction solution to become a regeneration induction solution which is a concentrated dilution induction solution, and is discharged from the membrane unit for membrane distillation. The obtained regeneration-inducing solution can be reused as an inducing solution as it is or after adjusting the concentration as needed.
Further, from the second viewpoint, the solvent is separated from the inducing solution to become a concentrated inducing solution, which is a concentrated inducing solution, and is discharged from the membrane unit for membrane distillation. The obtained concentration-inducing solution is mixed with the dilution-inducing solution to form a mixed solution, and then adjusted to a predetermined concentration as necessary to obtain a regeneration-inducing solution. The obtained regeneration-inducing solution can be reused as it is as an inducing solution.
The induction solution regenerated by the induction solution regeneration step may be reused after adjusting the temperature using an appropriate cooling device.
As the cooling device in the above, for example, a chiller, a heat exchanger, or the like can be used.
In these induction solution regeneration steps, the dilution induction solution or the solvent separated from the induction solution may be reused as needed.

In the following examples and comparative examples, a raw material liquid concentrating system having two or three forward osmosis membrane units connected in series is used, and the raw material liquid that has passed through the two or three forward osmosis membrane units is used. , The circulation concentration operation was performed by the method of returning to the first forward osmosis membrane unit again by the circulation mechanism.
This circulation concentration operation was performed in the following two stages, and the linear velocity of the raw material solution and the induction solution was set for each stage.
[First stage]
A step of diluting the stock solution with water and adjusting the solution viscosity to 1.0 cP as a raw material solution, and concentrating the solution to a solution viscosity of 20 cP by the above circulation concentration operation.
[Second stage]
A step of using the solution having a solution viscosity of 20 cP obtained in the first step as a raw material solution and concentrating it to a predetermined solution viscosity by the same circulation concentration operation.

The linear velocities of the raw material solution and the inductive solution were calculated by the above formulas from the flow velocities of the raw material solution and the inductive solution measured using the flow sensor: type "FD-X" manufactured by KEYENCE CORPORATION, respectively.

[Example 1]
In Example 1, the raw material squeeze concentrating step was carried out using the raw material liquid concentrating system having the configuration shown in FIG.
≪Preparation of raw material liquid concentration system≫
<Preparation of a forward osmosis membrane unit having a forward osmosis membrane o>
(1) Preparation of Hollow Fiber Support Membrane Module 20% by mass of polyether sulfone (PES: manufactured by BASF, trade name "Ultrason") dissolved in N-methyl-2-pyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd.). Hollow fiber spinning stock solution was prepared. A wet hollow fiber spinning machine equipped with a double spun was filled with the above-mentioned spinning stock solution and extruded into a coagulation tank filled with water to form hollow fibers by phase separation. The obtained hollow fiber was wound on a winder. The outer diameter of the obtained hollow fiber was 1,000 μm, the inner diameter was 700 μm, and the diameter of the fine pores on the inner surface was 0.05 μm. This hollow fiber was used as a support film.
The 130 hollow fiber-shaped support membranes are filled in a cylindrical plastic housing having a diameter of 2 cm and a length of 10 cm, and both ends of the hollow fibers are fixed with an adhesive so as not to block the internal space, whereby the effective inner surface area of the membrane is 0. A 023 m ² hollow fiber support membrane module was prepared.

(2) Preparation of forward osmosis membrane unit 10 g of m-phenylenediamine and 0.8 g of sodium lauryl sulfate are placed in a 0.5 L container, and 489.2 g of pure water is further added and dissolved to prepare a first solution used for interfacial polymerization. 0.5 kg was prepared.
In another 0.5 L container, 0.8 g of trimesic acid chloride was placed, and 399.2 g of n-hexane was added and dissolved to prepare 0.4 kg of a second solution used for interfacial polymerization.
The core side (inside of the hollow fiber) of the hollow fiber support membrane module obtained above is filled with the first solution, allowed to stand for 30 minutes, then drained, and a thin liquid film of the first solution is formed inside the hollow fiber. Was formed.
Next, the core side pressure was set to normal pressure by the core side pressure adjusting device, and the shell side pressure was set to a reduced pressure of 10 kPa as an absolute pressure by the shell side pressure adjusting device. After allowing to stand for 30 minutes in this state, while maintaining this pressure, the second solution is pumped to the core side at a flow rate of 1.5 L / min for 3 minutes to carry out interfacial polymerization. went. The polymerization temperature was 25 ° C.
Next, the hollow fiber membrane module was removed from the apparatus, and nitrogen at 50 ° C. was flowed to the core side for 30 minutes to volatilize and remove n-hexane. Further, by cleaning both the shell side and the core side with pure water, the forward osmosis membrane unit, which is a module of the hollow filament forward osmosis membrane o having a separation active layer made of polyamide on the inner surface of the hollow filamentous support membrane. Was produced.
The cross-sectional area of the raw material liquid flow path (total cross-sectional area of the hollow portion of the hollow fiber) of the obtained forward osmosis membrane unit is 0.50 cm ² , and the cross-sectional area of the inductive solution flow path (in the inner space of the housing of the unit). The value obtained by subtracting the total cross-sectional area of the hollow fiber forward osmosis membrane contained in the unit from the cross-sectional area) was 1.79 cm ² .

<Preparation of induction solution regeneration unit>
23 parts by mass of hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd., product name "AEROSIL-R972") with an average primary particle size of 0.016 μm and a specific surface area of 110 m ^{2 / g, 31 parts by mass of dioctyl phthalate (DOP), and phthalic acid.} After mixing 6 parts by mass of dibutyl (DBP) with a Henschel mixer, 40 parts by mass of polyvinylidene fluoride (manufactured by SOLVAY, product name "Solef6010") having a weight average molecular weight of 310,000 was added and mixed again with a Henschel mixer. To obtain the mixture. This mixture was pelletized by a twin-screw kneading extruder.
The obtained pellets were melt-kneaded at 240 ° C. with a twin-screw kneading extruder and extruded into hollow filaments to obtain hollow filaments. At this time, a hollow yarn forming spun is attached to the extrusion port in the head at the tip of the extruder, and the kneaded melt is extruded from the ring hole for extrusion of the melt, and at the same time, inside the ring hole for extrusion of the melt. Extrusion was performed in the form of a hollow thread by discharging nitrogen gas from a circular hole for discharging a hollow portion-forming fluid.
The hollow filament was introduced into a water bath (40 ° C.) at a free running distance of 20 cm and wound at a speed of 20 m / min.

The obtained hollow filaments were continuously picked up by a pair of first endless track type belt pickers at a speed of 20 m / min, and a first heating tank (0.8 m length) controlled to a space temperature of 40 ° C. was used. After passing through, the belt was picked up by a second track type belt picker at a speed of 40 m / min and stretched 2.0 times in the length direction. Then, after passing through a second heating tank (0.8 m long) in which the space temperature was controlled to 80 ° C., the mixture was cooled while being periodically bent on the water surface of the cooling water tank at 20 ° C. After that, it was picked up at a speed of 30 m / min by a third endless track type belt picker, and the stretched hollow filament was contracted (relaxed) up to 1.5 times in the length direction, and then the circumference was about 3 m. It was wound up with a belt. Periodic bending on the water surface of the cooling water tank was performed by continuously sandwiching a hollow filament-like object at a rotation speed of 170 rpm using a pair of concave-convex rolls having a peripheral length of about 0.20 m and four ridges.

The hollow filament after the above treatment was immersed in methylene chloride to extract and remove DOP and DBP, and then dried. Next, the treated hollow filament was immersed in a 50 mass% ethyl alcohol aqueous solution and then immersed in a 5 mass% sodium hydroxide aqueous solution at 40 ° C. for 1 hour to extract and remove silica. Then, it was washed with water and dried to obtain a hollow fiber membrane. The outer diameter of the obtained hollow fiber was 1250 μm, the inner diameter was 700 μm, and the diameter of the fine pores on the inner surface was 0.1 μm. This hollow fiber was used as a porous membrane.
It is effective by filling 70 porous membranes made of the above hollow fibers into a cylindrical plastic housing having a diameter of 2 cm and a length of 10 cm, and fixing both ends with an adhesive so that the hollow portions of the hollow fibers are not blocked. An inductive solution regeneration unit, which is a module of a hollow fiber-like porous membrane having an inner surface area of 0.012 m ^{2, was prepared.}
The permeation flux (permeability) of the water of this unit measured using pure water as the treatment liquid and 3.5 mass% saline as the induction solution was 20.02 L / (m ² × hr). rice field.

<Construction of raw material liquid concentration system>
In Example 1, the raw material liquid was concentrated using the raw material liquid concentrating system having the configuration shown in FIG.
The two forward osmosis membrane units obtained above are arranged in series so that the raw material solution is introduced into the hollow portion of the hollow filamentous forward osmosis membrane contained in these units and the induction solution is introduced into the outer portion. , Connected the piping. Here, in order to introduce the concentrated raw material liquid through the two forward osmosis membrane units into the forward osmosis membrane unit again, a circulation mechanism of the raw material liquid was arranged.
On the other hand, using one of the induction solution regeneration units obtained above, a membrane distillation apparatus was assembled in which the hollow portion of the hollow fiber contained in the unit was a liquid phase portion and the outer portion was a gas phase portion.
Then, the two forward osmosis membrane units and the membrane distillation apparatus are connected by piping via a mixing mechanism, and the dilution induction solution discharged from the forward osmosis membrane unit is concentrated by the induction solution regeneration unit, and the mixing mechanism is used. After adjusting the concentration, it was configured so that it could be reused as an induction solution to be introduced into the forward osmosis membrane unit.

With the system having the above configuration, the forward osmosis concentration step and the inductive solution attitude step were carried out.
The operating conditions for each process are as follows.

(1) Forward osmosis concentration step Raw material solution: A solution obtained by diluting maple sap with water to adjust the viscosity to 1.0 cP. Linear velocity of the raw material solution First stage (concentration from 1.0 cP to 20 cP): 5.0 cm / s
Second stage (concentration from 20 cP to 50 cP): 0.9 cm / s
Inducing solution type: 20 wt% magnesium chloride aqueous solution Linear velocity of inducing solution: 2.0 cP (constant throughout the first and second stages)
Processing temperature: 25 ° C
Filtration method: Cross flow method (2) Induction solution regeneration process Dilution induction solution flow velocity: 600 ml / min Gas phase pressure: 10 kPa (absolute pressure)

<Evaluation>
(Measurement of permeation flux (permeability) of the medium transferred from the raw material solution to the induction solution)
One minute after the start of operation, the amount (L) of the medium (water) transferred from the raw material solution transferred during operation to the induction solution via the forward osmosis membrane is measured by an electronic balance (type) manufactured by A & D Co., Ltd. The measurement was carried out under the name "GX-12K"), and the permeation flux (water permeation amount) was calculated according to the following formula (1).
F = L / (M × H) (1)
Here, F is the amount of water permeation of the medium (L / (m ² × hr)), L is the amount of the medium that has permeated the forward osmosis membrane (unit: L), and M is the surface area (unit: unit) of the forward osmosis membrane. : ^{M 2} ), and H is time (unit: hr).
From the obtained value of the water permeation amount L, it was evaluated according to the following criteria.
A: When the permeated flux exceeds 3.0 B: When the permeated flux is 1.0 or more and 3.0 or less C: When the permeated flux is 0.5 or more and less than 1.0 D: Permeated flux Is less than 0.5

(Viscosity analysis)
The viscosities of the raw material solution and the obtained concentrated solution were measured as the solution viscosity by a viscometer manufactured by Thermo Scientific (model name "HAAKE ViscoTester iQ").

(Long-term drivability)
The long-term operability of the raw material liquid concentration system was evaluated according to the following criteria.
When the concentration of the raw material liquid that was circulated and concentrated reached a predetermined concentration, the operation was temporarily stopped, the system was washed and inspected, and the permeation flow velocity was measured. If the permeation flow velocity value obtained in the inspection exceeds 80% of the previous measurement value, the concentration operation is continued, and if it is 80% or less of the previous inspection value, the concentration operation is terminated at that point. ..
The cleaning and inspection of the raw material liquid concentration system were carried out as follows.

-Washing-
The circulation of the raw material liquid was continued after removing the raw material liquid, leaving the minimum amount capable of continuing the normal circulation of the raw material liquid. In this state, water was circulated instead of the inductive solution and operated for 30 minutes to perform the first washing step.
Next, while the circulation of water instead of the inductive solution was continued, water was circulated instead of the raw material solution, and the water was configured to circulate on both sides of the forward osmosis membrane, and operated for 60 minutes. A cleaning step was performed. During the second washing step, the water circulated on both sides of the forward osmosis membrane was replaced with fresh water once every 20 minutes.
The forward osmosis membrane was washed by a series of these operations.

-test-
After cleaning, while maintaining the circulation of water on the raw material liquid side, the water on the inductive solution side was changed to an aqueous solution containing 20% by mass of magnesium chloride and circulated for operation, and the amount of water permeation of the system after cleaning was measured. ..
When the value of the obtained water permeation amount was more than 80% of the previous inspection value, the raw material solution and the induction solution were returned to the conditions before washing and circulated, and the concentration operation was continued. On the other hand, when the value of the hydraulic conductivity was 80% or less of the previous inspection value, the operation was terminated at that time, and the long-term operability was evaluated according to the following criteria based on the time from the start of the operation to the end of the operation. .. A: I was able to drive for 1,000 hours without any problems.
B: In the range of 500 hours or more and less than 1,000 hours, the operation was able to be performed without any problem.
C: In the range of 100 hours or more and less than 500 hours, the operation could be performed without any problem.
D: I was able to drive without problems in the range of 10 hours or more and less than 100 hours E: I could not drive for 10 hours

[Examples 2 to 5, 9 to 18, and 20 to 22, and Comparative Examples 1 to 5]
In these examples, the raw material solution concentration system having the configuration shown in FIG. 12 was used to determine the type of stock solution, the linear velocity and post-concentration viscosity of the raw material solution in the second stage of concentration, and the linear velocity of the induced solution. The raw material solution was concentrated in two steps in the same manner as in Example 1, except that each of them was changed as shown in Table 3.
In Comparative Example 5, when the viscosity of the concentrated raw material liquid circulated and introduced into the forward osmosis membrane unit exceeded 600 cP during the second stage concentration, it became difficult to transfer the solution. The operation was stopped.

[Examples 6 to 8, 23, and 24]
In these examples, the concentration of the raw material solution (diluted maple sap, viscosity 1 cP) was concentrated in two steps in the same manner as in Example 1 except that the raw material solution concentration system having the configuration shown in FIG. 13 was used. went.
The raw material liquid concentration system of FIG. 13 has a three-stage forward osmosis membrane unit. The units at each of these stages are referred to as a forward osmosis membrane unit A, a forward osmosis membrane unit B, and a forward osmosis membrane unit C in order from the upstream side of the raw material liquid.
_{In these examples, the ratios A 2} / A ₁ and A ₃ / are used as the forward osmosis membrane units A, B, and C by connecting the units shown in Table 1 below in parallel, respectively. The value of A _{2 was adjusted.}

[Examples 9 and 10]
In Example 9, the raw material liquid (diluted maple sap, viscosity 1 cp) was concentrated using the raw material liquid concentration system having the configuration shown in FIG.
The raw material liquid concentrating system shown in FIG. 16 has the same configuration as the raw material liquid concentrating system of FIG. 12 used in Example 1 except that a liquid feeding pump is arranged between two forward osmosis membrane units connected in series. Has.

[Example 19]
In Example 19, the hollow filamentous support membrane module was prepared by the following procedure, and the raw material liquid was concentrated under the same conditions as in Example 1 except that the material of the hollow filamentous support membrane was polyketone.
(Manufacturing of hollow filamentous support membrane module)
A polyketone having an extreme viscosity of 3.4 dl / g, in which ethylene and carbon monoxide are completely alternately copolymerized, is added to a 65 mass% resorcin aqueous solution so that the polymer concentration is 10.7 mass%, and the mixture is stirred at 80 ° C. for 2 hours. It was dissolved and defoamed to obtain a uniform and transparent undiluted solution.
A wet hollow fiber spinning machine equipped with a double spinner was filled with the above stock solution, the temperature was adjusted to 50 ° C., and the hollow fiber was extruded into a coagulation tank filled with water to form hollow fibers by phase separation. The obtained hollow fiber was wound on a winder. The outer diameter of the obtained hollow fiber was 1.0 mm, the inner diameter was 0.7 mm, the diameter of the fine pores on the inner surface was 0.15 μm, and the water permeability was 950 L / (m ² × hr) / 100 kPa.
This hollow fiber was used as a support film. The 130 hollow fiber-shaped support membranes are filled in a cylindrical plastic housing having a diameter of 2 cm and a length of 10 cm, and both ends are fixed with an adhesive so as not to block the internal space of the hollow fibers. A 023 m ² hollow fiber support membrane module was prepared.

The evaluation results are summarized in Table 2 below.

[Example 25]
In Example 25, the raw material liquid concentrating system having the configuration shown in FIG. 12 is used, and the raw material liquid that has passed through the two forward osmosis membrane units is returned to the first forward osmosis membrane unit by the circulation mechanism. The raw material liquid was concentrated.
This circulation concentration operation was performed in the following two stages, and the linear velocity of the raw material solution and the induction solution was set for each stage.
First step: Concentration from Brix value 2 (solution viscosity 1 cp) to Brix value 40 (solution viscosity 20 cP) Second step: Concentration from Brix value 40 (solution viscosity 20 cP) to Brix value 300 (solution viscosity 300 cP) Other than the above The operating conditions of the above were set to be the same as those of the first embodiment.
<Evaluation>
The measurement of the permeation flux (permeability) of the medium transferred from the raw material solution to the induction solution, the analysis of the viscosity, and the long-term operability were each evaluated in the same manner as in Example 1.
The analysis of sugar content and absorbance and the sensory evaluation of flavor were performed as follows.

(Analysis of sugar content)
The concentrations of the raw material liquid and the obtained concentrated liquid were measured as Brix values by a sugar content meter "PAL-S" manufactured by Atago Co., Ltd.
(Absorbance)
The obtained concentrate was filtered through an ultrafiltration filter (Amicon Ultra-0.5, PLGC Ultracell-10 Membrane, 10 kDa, UFC501008). The obtained filtrate was filled in a two-sided transparent quartz cell with a screw cap for a spectrophotometer (manufactured by GL Sciences Co., Ltd., S15-UV-10, optical path length 10 mm, optical path width 10 mm).
Ultraviolet-visible spectroscopic analysis was performed with this filtrate as the sample side and the above-mentioned distilled water as the reference side, and the absorbance at a wavelength of 450 nm was examined.
The conditions for ultraviolet-visible spectroscopic analysis were as follows.
Measuring device: JASCO V-770 manufactured by JASCO Corporation
Measurement mode: Abs
Measurement wavelength: 800-200 nm
Data acquisition interval: 0.5 nm
Light source: D2, WI
Light source switching: 340 nm
Correction: Baseline

(Sensory evaluation of flavor)
The obtained concentrated liquid was diluted with pure water, and the concentrated liquid reduced liquid adjusted to the same concentration as the raw material liquid before concentration was used for the taste of five panelists, and the flavor was evaluated according to the following criteria.
A: All five panelists judged that the original flavor of the ingredients was strong.
B: The number of panelists who judged that the original flavor of the raw material was strong was 1 or more and 4 or less.
C: None of the panelists judged that the original flavor of the raw material was strong.

[Example 26]
The same procedure as in Example 25 was carried out except that the raw material solution was coconut liquid endosperm and the reached Brix value in the second stage was 50.
[Example 27]
The Brix value reached in the second step was 60 and the others were carried out in the same manner as in Example 25 to obtain a concentrate. Next, distillation was carried out at 110 ° C. using an atmospheric distillation apparatus, and the product was concentrated to a Brix value of 70 to obtain a final product.
[Example 28]
It was carried out in the same manner as in Example 27 except that the reached Brix value in the second stage was set to 50.

[Comparative Example 6]
Maple sap, which is a raw material liquid, was concentrated by a distillation method.
Distillation was carried out at 110 ° C. using an atmospheric distillation apparatus.
[Comparative Example 7]
Maple sap, which is a raw material liquid, was concentrated to a Brix value of 20 by a reverse osmosis method, and then further concentrated to a Brix value of 70 by a distillation method.
The reverse osmosis method was carried out using a product number "NTR-759HR" manufactured by Nitto Denko Corporation as a reverse osmosis membrane at an operating pressure of 2.0 MPa.
The distillation method was carried out at 110 ° C. using an atmospheric distillation apparatus. The sample viscosity before distillation was 100 cP, and the sample viscosity after distillation was 300 cP.
[Comparative Example 8]
Maple sap, which is a raw material liquid, was concentrated to a Brix value of 20 by a forward osmosis method, and then further concentrated to a Brix value of 70 by a distillation method.
The forward osmosis method was carried out in the same manner as in the first step of Example 25, except that the reached Brix value was set as described above.
The distillation method was carried out at 110 ° C. using an atmospheric distillation apparatus. The sample viscosity before distillation was 40 cP, and the sample viscosity after distillation was 300 cP.

The evaluation results are summarized in Table 3 below.

Claims

A raw material solution containing a solvent and a solute and an inducing solution containing an inducing substance are brought into contact with each other via a normal osmotic membrane, and the solvent in the raw material solution is moved into the inducing solution to obtain a dilution inducing solution. A method for concentrating a raw material solution, which comprises a step of concentrating the raw material solution while obtaining the raw material solution.
The forward osmosis membrane has a hollow thread shape and is in the form of a hollow thread.
The method for concentrating the raw material liquid includes a step of circulating the raw material liquid through the hollow portion of the hollow thread-shaped forward osmosis membrane and circulating the induction solution outside the hollow thread-shaped forward osmosis membrane.
When the viscosity of the raw material liquid flowing into the hollow portion of the hollow thread-like forward osmosis membrane is 20 cP or more and 600 cP or less, the linear velocity of the raw material liquid flowing into the hollow portion of the hollow thread-like forward osmosis membrane is set to 0. 1 cm / s or more and 5.0 cm / s or less,
Method of concentrating raw material liquid.
When the viscosity of the raw material liquid flowing into the hollow portion of the hollow thread-like forward osmosis membrane is 20 cP or more and 600 cP or less, the linear velocity of the raw material liquid flowing into the hollow portion of the hollow thread-shaped forward osmosis membrane is 0.9 cm. The method for concentrating a raw material liquid according to claim 1, wherein the concentration is at least / s and 3.5 cm / s or less.
A raw material solution containing a solvent and a solute and an inducing solution containing an inducing substance are brought into contact with each other via a normal osmotic membrane, and the solvent in the raw material solution is moved into the inducing solution to obtain a dilution inducing solution. A method for concentrating a raw material solution, which comprises a step of concentrating the raw material solution while obtaining the raw material solution.
The forward osmosis membrane has a hollow thread shape and is in the form of a hollow thread.
The method for concentrating the raw material liquid includes a step of circulating the raw material liquid through the hollow portion of the hollow thread-shaped forward osmosis membrane and circulating the induction solution outside the hollow thread-shaped forward osmosis membrane.
The linear velocity of the induction solution flowing into the outside of the forward osmosis membrane is 0.1 cm / s or more and 10 cm / s or less.
Method of concentrating raw material liquid.
The method for concentrating a raw material solution according to any one of claims 1 to 3, wherein the induction solution is an inorganic salt solution containing a divalent cation.
The positive osmotic membrane is from polyethersulfone, polysulfone, polyketone, polyether etherketone, polyphenylene ether, polyvinylidene fluoride, polyacrylonitrile, polyimine, polyimide, polybenzoxazole, polybenzoimidazole, sulfonated tetrafluoroethylene, and polyamide. The method for concentrating a raw material solution according to any one of claims 1 to 4, which is a film having a thin film layer containing at least one selected from the group as a main component.
A method for concentrating a raw material liquid, wherein the raw material liquid concentrating step is performed in two or more steps in series.
In succession two steps of the raw material solution concentration step is carried out of the two or more stages of the raw material solution concentration step, the raw material liquid flow path cross-sectional area A d of the forward osmosis membrane used in the subsequent stage of the raw material solution concentration step, preceding the ratio a d / a u for feed liquid flow path cross-sectional area a u of the forward osmosis membrane is 0.2 to 10,
The method for concentrating a raw material liquid according to any one of claims 1 to 5.
Raw material liquid flow path cross-sectional area A d of the forward osmosis membrane used in the subsequent stage of the raw material solution concentration step, the ratio based on the starting material liquid flow path cross-sectional area A u of forward osmosis membrane used in the preceding stage of the raw material solution concentration step A d / A The method for concentrating a raw material liquid according to claim 6, wherein u is 2 or more and 8 or less.
In the raw material liquid concentrating step performed in two or more steps in series, in order to supply the raw material liquid concentrated in the raw material liquid concentrating step in the previous stage as the raw material liquid in the raw material liquid concentrating step in the subsequent stage, one raw material liquid feeding pump is used. The method for concentrating a raw material liquid according to claim 6 or 7, wherein one or more of them are used.
Further comprising an induction solution concentration step of removing the solvent from the dilution induction solution to obtain a regeneration induction solution.
The concentrated induction solution obtained in the induction solution concentration step is used again as the induction solution.
The method for concentrating a raw material liquid according to any one of claims 1 to 8.
Induction solution concentration step of removing the solvent from the induction solution to obtain a concentration induction solution, and
Further comprising a mixing step of mixing the concentration-inducing solution obtained in the induction solution concentration step with the dilution-inducing solution.
The mixed solution obtained in the mixing step is used again as the induction solution.
The method for concentrating a raw material liquid according to any one of claims 1 to 8.
The method for concentrating a raw material solution according to claim 9 or 10, wherein the induction solution concentration step is performed by an evaporation means.
The first method of cleaning the forward osmosis membrane by bringing the raw material solution and a diluted solution of the induction solution or the solvent whose osmotic pressure is adjusted to be lower than that of the raw material solution are brought into contact with each other via the forward osmosis membrane. The method for concentrating a raw material solution according to any one of claims 1 to 11, which comprises the cleaning step of.
The raw material solution according to claim 12, further comprising a second cleaning step of cleaning the forward osmosis membrane by bringing the solvent into contact with both sides of the forward osmosis membrane after the first cleaning step. Concentration method.
A food product that is a concentrate of a solute containing sugar and a raw material liquid containing a liquid medium.
The concentrate is
Brix value is 50 or more and
The absorbance at 450 nm in ultraviolet-visible spectroscopy is 0.1 or more and 1.0 or less.
Grocery.
The food product according to claim 14, wherein the absorbance at 450 nm in the ultraviolet-visible spectroscopic analysis of the concentrated solution is 0.2 or more and 0.8 or less.
The food product according to claim 14 or 15, wherein the raw material liquid is maple sap or coconut liquid endosperm.