WO2011037154A1 - Method for manufacturing desalted whey - Google Patents

Abstract

Provided is a method for manufacturing desalted whey, said method including: a step in which a liquid to be supplied to a desalting process is passed through an ion-exchange resin before being desalted; and a step in which the liquid which has passed through the ion-exchange resin is desalted via a membrane separation process. The aforementioned ion-exchange resin comprises an anion-exchange resin. At least a chlorine anion-exchange resin is used as the anion-exchange resin. The provided method can efficiently manufacture desalted whey in which the sodium and potassium content has been sufficiently reduced, while minimizing loss of the calcium and magnesium that the starting whey contains.

Description

Method for producing desalted whey

The present invention relates to a method for producing desalted whey.
This application claims priority based on Japanese Patent Application No. 2009-219862 filed in Japan on September 25, 2009, the contents of which are incorporated herein by reference.

Whey is a by-product of dairy products such as cheese. In general, whey (whey) is used as a raw material for whey protein and lactose, as well as a raw material for improving the flavor of bread or baked confectionery, a raw material for beverages, a raw material for infant formula, and the like.
Whey has a unique flavor and has a limited use because it contains a large amount of minerals. Therefore, many methods have been proposed as a method for desalting whey. Examples of the method for desalting whey include an ion exchange method, a nanofiltration method, and an electrodialysis method.

Among the minerals contained in whey, calcium and magnesium are important nutrients whose intake standards are set in each country, as shown in the “Japanese dietary intake standards (2005 edition)”. It is. However, in Japan, for example, according to the “2005 National Health and Nutrition Survey Results”, the rate of satisfaction with the dietary intake standard is insufficient. For this reason, calcium and magnesium fortified foods and supplements are widely distributed. Calcium and magnesium are defined as nutritional ingredients that can be labeled as functional nutritional foods. By satisfying certain requirements, the functions of calcium and magnesium can be demonstrated and their nutritional significance is widely recognized. .

Dairy products are expected as a good source of calcium, and whey is no exception. In desalting whey, it is desirable not only to simply reduce the mineral content, but also to desalinate only monovalent minerals such as sodium and potassium while leaving divalent cations, ie calcium and magnesium.

Conventional methods of desalting whey using ion exchange resins preferentially remove not only monovalent cations but also divalent cations such as calcium and magnesium, which are nutritionally valuable.
For example, in the method described in Non-Patent Document 1, whey is first passed through a hydrogen-type cation exchange resin, and metal cations are replaced with hydrogen ions to become acidic and flow out. Next, the effluent is passed through a hydroxyl group-type anion exchange resin, and desalting is carried out by replacing anions (citric acid, phosphoric acid, chlorine, lactic acid) with hydroxide ions. According to this method, a high desalting rate of 90 to 98% can be achieved, but calcium and magnesium are also removed.

The method described in Patent Document 1 is a method in which liquid passing through an ion exchange resin and electrodialysis are combined. Here, concentrated whey is first introduced into a weakly cationic or carboxylic acid column, 60-70% of divalent cations are ion exchanged with protons, and 5-15% of monovalent cations are ion exchanged with protons. The resulting effluent is then introduced into a mixed bed column of strong cationic ion exchange resin and strong anionic ion exchange resin, the remaining calcium and magnesium ions are exchanged for protons, and sodium and potassium ions are exchanged for protons. Then, the sulfate anion is ion-exchanged with the chloride anion to become strongly acidic (pH 2 to 2.5). Thereafter, most of the chloride anions and most of the protons are removed by introduction into an electrodialyzer, and further introduced into a strong anionic ion exchange resin to exchange citrate ions and phosphate ions with chloride ions. This method describes that 60% or more of divalent cations (calcium and magnesium) are removed.

There is a membrane separation method as a method of desalting only monovalent minerals such as sodium and potassium while leaving divalent cations.
Patent Document 2 proposes a method for reducing the contents of sodium and potassium using a nanofiltration method which is a kind of membrane separation method.
However, the desalting by nanofiltration has a problem that the desalting efficiency decreases as the desalting rate increases. Therefore, in order to achieve a high desalting rate, it is necessary to perform membrane filtration for a long time, for example, and the production efficiency is poor.

Patent Document 3 proposes a method of adding an electrolyte (milk casein, whey protein concentrate, etc.) that does not permeate the nanofiltration membrane to the milk before desalting in order to promote desalting in the nanofiltration method. ing.
Non-Patent Document 2 reports that calcium chloride is added in the nanofiltration method in order to reduce the sodium ion blocking rate of the sodium chloride solution.

Japanese Patent No. 3295696 JP-A-8-266221 JP 2004-180580 A

However, in the method described in Patent Document 3, the electrolyte to be added (milk casein, whey protein concentrate, etc.) itself has economic value and is economically inefficient.
In the method described in Non-Patent Document 2, according to the knowledge of the present inventors, the addition of calcium chloride reduces the permeation flux, that is, the amount of liquid passing through the membrane per unit time. However, there is a drawback that the desalting efficiency becomes worse. Moreover, since calcium chloride is added, the calcium content in the obtained desalted whey is higher than that of the raw material whey, which may not be preferable depending on the application.

The present invention has been made in view of the above circumstances, and efficiently produces desalted whey in which sodium and potassium are sufficiently reduced while suppressing the reduction of the contents of calcium and magnesium contained in the raw material whey. It aims to provide a possible method.

In order to solve the above-mentioned problems, the present inventors have conducted intensive research. As a result, in the desalination treatment of whey by the membrane separation method, the total of the sodium content and the potassium content in the liquid to be treated is a treatment target. It was found that when the molar ratio of the chlorine content to the value, that is, the value of (chlorine / (sodium + potassium)) is small, the permeation rate of sodium and potassium in the separation membrane is reduced, and the desalting efficiency is lowered.
The molar ratio (chlorine / (potassium + sodium)) can be increased by passing the liquid to be treated through a chlorine-type anion exchange resin, and the molar ratio (chlorine / (potassium + sodium)) is increased. It was found that sodium and potassium can be efficiently desalted by performing membrane separation in a state where the reduction of the content of calcium and magnesium contained in whey can be suppressed, and the present invention has been completed. .

One aspect of the present invention is a method for producing desalted whey from a raw material whey solution through a step of performing a desalting treatment by a membrane separation method, and a liquid to be treated to be subjected to the desalting treatment, Having a step of passing through an ion exchange resin before desalting, wherein the ion exchange resin is made of an anion exchange resin, and at least a chlorine type anion exchange resin is used as the anion exchange resin. The present invention relates to a method for producing desalted whey.

According to another aspect of the present invention, a treatment liquid to be subjected to desalting treatment is passed through an ion exchange resin before being desalted, and the passed treatment liquid is subjected to membrane separation. The present invention relates to a method for producing desalted whey, wherein the ion exchange resin is made of an anion exchange resin, and at least a chlorine type anion exchange resin is used as the anion exchange resin.

In another aspect of the present invention, the liquid to be treated for the desalting treatment is a raw material whey liquid, and the pH of the raw material whey liquid is, for example, 5.5 to 7.4, more preferably 6 The present invention relates to a method for producing desalted whey, wherein the pH of the effluent from the anion exchange resin is in the range of 5.5 to 7.4, more preferably 6 to 7.
Another aspect of the present invention relates to a method for producing desalted whey in which the membrane separation method is a nanofiltration method.

As another aspect of the present invention, the molar ratio of chlorine content to the total value of sodium content and potassium content (chlorine / (sodium + potassium)) of the liquid to be treated for the desalting treatment. The present invention relates to a method for producing a desalted whey that maintains 0.35 or more.
As another aspect of the present invention, the molar ratio (chlorine / (sodium + potassium)) of chlorine content to the total value of sodium content and potassium content in the effluent from the chlorine-type anion exchange resin is as follows. The present invention relates to a method for producing desalted whey performed under conditions of 0.8 or more.

As another aspect of the present invention, the (Ca + Mg) residual rate determined by the following formula (1) in the desalted whey is 60% or more, and the desalting rate calculated by the following formula (2) is 60%. The present invention relates to a method for producing desalted whey as described above.
(Ca + Mg) residual rate (unit:%) = {(total of Ca content and Mg content of desalted whey) / (total of Ca content and Mg content of raw whey solution)} × 100 (1) (In the formula, the Ca content is the content of calcium contained per 100 g of the solid content, the Mg content is the content of magnesium contained per 100 g of the solid content, and each unit is mmol / 100 g solid. .)
Desalination rate (unit:%) = {{(total of Na content and K content of raw material whey liquid) − (total of Na content and K content of desalted whey liquid)} / (Na of raw whey liquid) Total of content and K content)} × 100 (2) (In the formula, the Na content is the content of sodium contained per 100 g of solid content, and the K content is potassium contained per 100 g of solid content. In any case, the unit is mmol / 100 g solid.)
Yet another aspect of the present invention relates to the desalted whey, which is suitable for formula milk.

According to the method of the present invention, it is possible to efficiently produce a desalted whey in which sodium and potassium are sufficiently reduced while suppressing reduction of the contents of calcium and magnesium contained in the raw material whey.

It is a graph which shows the relationship between the integrated permeate amount of a nanofiltration membrane, and the desalination rate of sodium and potassium in an Example and a comparative example. It is a graph which shows the relationship between the amount of integrated permeated liquids and the permeation flux per unit membrane module in an Example and a comparative example.

The present invention will be described in detail. In the following, “%” is “% by mass” unless otherwise specified.
<Raw material whey>
A whey is a transparent liquid remaining after removing coagulated milk in the process of producing cheese, casein, sodium caseinate, yogurt or the like using milk such as cow, sheep or goat as a raw material. The whey used in the present invention may be an untreated whey obtained only by separating the coagulated milk, and the untreated whey is subjected to degreasing and / or deprotein pretreatment using a separation membrane. The untreated whey or the pretreated whey may be powdered by a conventional method such as spray drying or freeze drying. Commercial whey powder can also be used.

The raw material whey liquid may be a liquid containing whey. For example, liquid whey may be used as it is, or an aqueous solution of whey powder. You may use the concentrate concentrated beforehand as a raw material whey liquid as needed.
The whey and the raw material whey liquid are preferably neutral. Specifically, the pH of the raw material whey solution is preferably in the range of 5.5 to 7.4, more preferably 6 to 7, for example.
If the raw material whey solution is within the above range, the desalting step by the separation membrane and the step of passing through the ion exchange resin, which will be described later, can be performed in a neutral region without performing the neutralization step. Degradation, denaturation, acid decomposition of sugar, alkaline reaction, etc. can be prevented. In addition, it is preferable to use a separation membrane having low alkali resistance because there is no possibility of shortening the membrane life.

<Liquid flow to anion exchange resin>
The ion exchange resin in this invention consists of an anion exchange resin. That is, the process of passing the liquid through the cation exchange resin is not performed.
The liquid passing through the anion exchange resin is preferably performed in a neutral range. Specifically, the pH of the liquid before passing through the anion exchange resin and the pH of the effluent from the anion exchange resin are both, for example, pH 5.5 to 7.4, more preferably 6 It is preferably within the range of.
For this purpose, it is desirable to use a neutral raw material whey solution and not to use an OH type anion exchange resin as an anion exchange resin, and it is preferable to use only a chlorine type anion exchange resin as an anion exchange resin.

As the chlorine type anion exchange resin, an anion exchange resin that has been previously made into a chlorine type using saline or hydrochloric acid is used. Examples of the anion exchange resin include IRA402BL and IRA958 manufactured by Rohm and Haas, and PA316 manufactured by Mitsubishi Chemical (both are product names). However, the present invention is not limited thereto, and an anion exchange resin suitable for obtaining a desalted whey having a target composition can be appropriately selected according to the use of the desalted whey.

By passing the solution through a chlorine-type anion exchange resin, the chlorine content in the solution increases. At the time of passing through the chlorine-type anion exchange resin, the liquid to be treated to be subjected to the desalting treatment by the membrane separation method is passed before the desalting treatment. For example, the desalting treatment may be performed after passing the raw material whey solution through a chlorine-type anion exchange resin. Alternatively, the desalted whey solution that has been desalted by the membrane separation method may be passed through a chlorine-type anion exchange resin and then further subjected to a desalting treatment by the membrane-separation method. It is also possible to alternately repeat the flow of water through and the desalting treatment by the membrane separation method a plurality of times, and finally perform the desalting treatment by the membrane separation method. These may be combined.
Furthermore, the raw material whey is extracted from the raw material tank, passed through a chlorine-type anion exchange resin, and an operation for returning the obtained liquid to the raw material tank is added to perform membrane separation, thereby reducing the Cl / (Na + K) ratio. It is possible to maintain.

The increase in the chlorine content by passing through the chlorine type anion exchange resin is the chlorine content relative to the total of the sodium (Na) content and potassium (K) content in the effluent from the chlorine type anion exchange resin. The molar ratio (chlorine / (sodium + potassium)) (hereinafter sometimes referred to as the Cl / (Na + K) ratio) is preferably 0.8 or more.
Moreover, 1.1 is preferable from a viewpoint of manufacturing efficiency, and, as for the suitable upper limit of Cl / (Na + K) ratio, it is more preferable that it is 1.0. As will be described later, the value of the Cl / (Na + K) ratio increases as the amount of whey solids per unit exchange capacity of the chlorine-type anion exchange resin decreases.
When the Cl / (Na + K) ratio is 0.8 or more, it is easy to keep the Cl / (Na + K) ratio in the liquid to be processed to be desalted in the separation membrane described later at 0.35 or more.
For example, in the desalting treatment by batch concentration method or diafiltration described later, Cl / (Na + K in the liquid to be treated used for the desalting treatment by the separation membrane unless the chlorine content is increased in the middle. ) The ratio may decrease over time. In this case, if the Cl / (Na + K) ratio of the liquid initially supplied for the desalting treatment is 0.8 or more, the Cl / (Na + K) of the liquid to be treated can be obtained without increasing the chlorine content in the middle. It is easy to maintain the ratio at 0.35 or higher.
The upper limit of the increase in chlorine content by passing through the chlorine-type anion exchange resin is not particularly limited, but it is necessary to make it within a range that does not hinder after the desalting step. It is preferable to set the chlorine content of the desalted whey within a preferable range according to the use of the desalted whey. For example, when desalted whey is used as a raw material for infant formula, the chlorine content of desalted whey can be exemplified by 1 to 25 mmol / 100 g solids.

The condition for passing through the chlorine-type anion exchange resin can be set in accordance with the target value of the chlorine content in the effluent as long as lactose does not precipitate.
When a whey-containing liquid is passed through a chlorine-type anion exchange resin, the smaller the amount of whey solids per unit exchange capacity of the ion exchange resin, the higher the ion exchange efficiency. The increase will increase. In order to increase the chlorine content in the effluent, it is preferable that the solid concentration of the liquid to be passed is lower and the flow rate is smaller (slower).
The solid concentration of the liquid passed through the chlorine-type anion exchange resin is preferably 4 to 40% by mass, for example, and more preferably 5 to 20% by mass. When the solid concentration is less than 4% by mass, it takes time to pass the liquid and the efficiency is not good. Further, the lower the solid concentration, the higher the concentration factor when performing the concentration in the subsequent step. When the solid concentration exceeds 40% by mass, the viscosity of the solution increases and the possibility of lactose precipitation increases.
For example, the flow rate when the liquid is passed is preferably 2 to 12 SV, and more preferably 3 to 8 SV. If the flow rate is less than 2 SV, it takes time to pass the liquid and the efficiency is not good. When the flow rate exceeds 12 SV, the pressure loss increases. SV represents a relative amount of the liquid passed per unit time with respect to the amount of the ion exchange resin, and a flow rate when the same amount of liquid as the amount of the ion exchange resin is passed for 1 hour is referred to as 1 SV.
The temperature of the liquid to be passed is preferably 2 to 50 ° C, more preferably 3 to 15 ° C. When the temperature is less than 2 ° C., the viscosity of the liquid becomes too high. If the temperature is too low, the liquid may freeze. On the other hand, when the temperature exceeds 50 ° C., the possibility of protein denaturation or browning increases. In order to suppress the growth of microorganisms, 10 ° C. or lower is preferable.
In general, the smaller the SV and the solid content concentration, the higher the ion exchange efficiency and the higher the Cl / (Na + K) ratio.
Moreover, the Cl / (Na + K) ratio tends to increase as the amount of whey solids per unit exchange capacity of the chlorine-type anion exchange resin decreases.
Specifically, whey containing 23.5 mmol / 100 g solid of sodium (Na), 66.5 mmol / 100 g solid of potassium (K), and 42.3 mmol / 100 g solid of chlorine (Cl) and having a concentration of 7 When the raw material whey liquid that is mass% is passed through the ion exchange resin at SV 6.5 under the condition of 10 ° C., the whey that passes through the ion exchange capacity (capacity) of the chlorine type anion exchange resin per 1 eq. If the solid content of the liquid is set to 2.2 kg or less, the Cl / (Na + K) ratio is 0.8 or more. “Eq” represents the ion exchange capacity of the ion exchange resin, and 1 eq means that 1 mol of charge can be exchanged.

<Desalting step of performing desalting treatment by membrane separation method>
As the membrane separation method used for the desalting treatment, a method having a high calcium and magnesium rejection and a high sodium and potassium permeability is used. For example, a known method can be used as a method for selectively desalting monovalent minerals, such as electrodialysis, nanofiltration, or dialysis. The nanofiltration method is preferable in that desalting and concentration can be performed at the same time, and advanced desalting is possible by combining diafiltration steps as necessary.

The nanofiltration method is a method having a step of separating a liquid to be treated for desalting treatment by nanofiltration into a permeated liquid that has permeated the nanofiltration membrane and a retentate liquid that has not permeated.
A nanofiltration (NF) membrane is an intermediate region between an ultrafiltration (UF) membrane and a reverse osmosis (RO) membrane that has a molecular weight of tens to thousands of daltons, that is, a nanometer region when converted to a molecular size. This is a separation membrane to be imaged. Among inorganic substances, carbohydrates, amino acids, vitamins, etc., particles having a low molecular weight and low charge permeate the nanofiltration membrane.

In the desalting step which is one aspect of the present invention, a part of the cation of the monovalent mineral among the minerals contained in the whey passes through the nanofiltration membrane and is contained in the permeate. On the other hand, divalent mineral cations hardly pass through the nanofiltration membrane and are contained in the retentate. Desalted whey is obtained from the retentate solution.
Specific nanofiltration membranes include DL, DK, HL series manufactured by GE Water Technologies, SR-3 series manufactured by Koch Membrane System, DOW-NF series manufactured by Dow Chemical, and NTR manufactured by Nitto Denko. A series (all are product names) can be exemplified, but is not limited thereto.
A separation membrane suitable for obtaining a desalted whey having a target composition can be appropriately selected and used depending on the application of the desalted whey.

As the membrane separation apparatus used in the present invention, a known apparatus can be appropriately selected and used.
For example, a membrane module equipped with a nanofiltration membrane, a supply pump that sends the liquid to be treated to the membrane module, a means for taking out the permeate that has permeated the nanofiltration membrane from the membrane module, and a retentate that did not permeate the nanofiltration membrane Means for taking out the membrane from the membrane module. The batch-type apparatus further includes a stock solution tank that holds the liquid to be treated before being supplied to the membrane module, and means for returning the retentate liquid taken out from the membrane module to the stock solution tank.
The membrane separation operation may be a batch concentration type in which the permeate is taken out and the retentate is returned to the stock solution tank. In addition to the step of taking out the permeate and returning the retentate solution to the stock solution tank, a step of performing diafiltration (hydrodiafiltration) in which the same amount of water as the taken out permeate is added to the stock solution tank may be provided. Alternatively, a continuous type may be employed in which the liquid to be treated is continuously supplied to the membrane module, and the retentate liquid and the permeated liquid are continuously extracted. These may be combined.

In this specification, the transmittance of sodium and potassium (hereinafter sometimes referred to as (Na + K) transmittance) is a value represented by the following formula (3). The unit of sodium content (hereinafter sometimes referred to as Na content) and potassium content (hereinafter sometimes referred to as K content) is mmol / L solution. (Na + K) permeability = (total of Na content and K content in permeate) / (total of Na content and K content in retentate) (3)

Maintain the Cl / (Na + K) ratio of chlorine content to the total value of Na content and K content at 0.35 or higher, preferably 0.5 or higher, in the liquid to be treated for desalination treatment with a separation membrane. It is preferable to do. When the Cl / (Na + K) ratio is 0.35 or more, the (Na + K) transmittance is sufficiently high.
When the Cl / (Na + K) ratio is 0.35 or more, the (Na + K) transmittance is sufficiently high. In order to prevent the Cl / (Na + K) ratio from becoming less than 0.35 during the desalting process by membrane separation, once the Cl / (Na + K) ratio is lowered, the chlorine-type anion exchange is performed again. It is possible to pass through the resin and then perform membrane separation. That is, in the production method of the present invention, the Cl / (Na + K) ratio can be maintained at 0.35 or more by repeating the anion exchange step a plurality of times.

Desalted whey is obtained from a retentate solution that has been desalted. The retentate obtained after the desalting treatment may be used as it is as a liquid desalted whey, and if necessary, a concentrated liquid desalted whey may be used as a concentrated liquid desalted whey. Further, after the retentate solution is concentrated as necessary, it may be converted into a powdered desalted whey through a normal drying process such as freeze drying or spray drying. Desalted whey can be used as a raw material for other products.
The total of the sodium content and the potassium content in the desalted whey is preferably 40 mmol or less, more preferably 32 mmol or less, per 100 g of the solid content.

According to the present invention, by providing a liquid to be processed to be subjected to a desalting treatment by a membrane separation method through a chlorine-type anion exchange resin before being desalted, the following examples are provided. As shown, (Na + K) permeability during the desalting step is kept at a high level, and desalting efficiency is improved. Therefore, a desalted whey having a sufficiently reduced content of sodium and potassium in the raw material whey can be efficiently produced. Moreover, the reduction of the content of calcium and magnesium contained in the raw material whey can be satisfactorily suppressed.

For example, a desalted whey having a residual rate of calcium and magnesium ((Ca + Mg) residual rate) of 60% or more and a desalting rate of 60% or more can be produced.
In the present specification, the (Ca + Mg) residual rate is a value obtained by the following formula (1), and the desalting rate is a value obtained by the following formula (2).
(Ca + Mg) residual rate (unit:%) = {(total of Ca content and Mg content of desalted whey) / (total of Ca content and Mg content of raw whey solution)} × 100 (1) (In the formula, the Ca content is the content of calcium contained per 100 g of the solid content, the Mg content is the content of magnesium contained per 100 g of the solid content, and each unit is mmol / 100 g solid. .)
Desalination rate (unit:%) = {{(total of Na content and K content of raw material whey liquid) − (total of Na content and K content of desalted whey liquid)} / (Na of raw whey liquid) Total of content and K content)} × 100 (2) (In the formula, the Na content is the content of sodium contained per 100 g of solid content, and the K content is potassium contained per 100 g of solid content. In any case, the unit is mmol / 100 g solid.)

The desalting rate can be controlled by the desalting conditions. For example, the desalination rate can be improved by elongating the desalting time, increasing the integrated permeate amount, or the like.
The residual ratio of (Ca + Mg) varies depending on the processing conditions when the liquid is passed through the ion exchange resin or the desalting conditions.

Also according to the present invention, Journal of membrane Science, Vol. 104, no. 3, P205-218 (1995) (Non-Patent Document 2), since the operation of adding calcium chloride is not performed, desalted whey without increasing the calcium content as compared with the raw material whey. Can be manufactured. Therefore, for example, desalted whey suitable for applications where the calcium content is too high compared to the raw material whey, such as desalted whey for prepared milk powder.
The formula powdered milk is obtained by processing raw milk, milk or special milk, or foods produced using these as raw materials, or using them as a main raw material, and adding the nutrients necessary for infants to a powder form.

Hereinafter, the present invention will be described in more detail using examples, but the present invention is not limited to these examples. In the following, “%” representing a unit of content is “% by mass” unless otherwise specified.
<Comparative Example 1>
(Raw material whey solution)
Cheese whey powder (protein 12.1%, fat 1.1%, carbohydrate 77.2%, ash content 7.8%, moisture 1.8%) 5.7kg as raw material whey, water was added to this It melt | dissolved and the raw material whey liquid of 105 kg was obtained. (Desalination by nanofiltration)
The obtained raw material whey solution was subjected to desalination treatment with a nanofiltration membrane (DL3840C-30D: manufactured by GE Water & Process Technologies) while returning the retentate solution to the stock solution tank until the permeate amounted to 66.6 kg. went. The liquid in the stock solution tank at this time is defined as desalted whey liquid (I).
Subsequently, by adding water amount equal to the permeate amount to the stock solution tank, the nanofiltration is continued by a hydrodiafiltration method that keeps the amount of liquid in the stock solution tank constant, and the permeate is 33.3 kg (desalting treatment). The desalting treatment was performed until the total reached 99.9 kg from the start. The liquid in the stock solution tank thus obtained is designated as desalted whey liquid (II). The recovered amount of desalted whey liquid (II) is 31.0 kg and contains 4.4 kg of solid content.

Regarding the raw material whey and the desalted whey solution (II), the composition per 100 g of the solid content is shown in Table 1, and the mineral composition per 100 g of the solid content (unit: mmol / 100 g solid, the same applies hereinafter) is shown in Table 2.
About raw material whey liquid, desalted whey liquid (I), and desalted whey liquid (II), the total of sodium (Na) content and potassium (K) content per 100 g of solid content (hereinafter referred to as Na + K) The total of Ca content and Mg content per 100 g of solid content (hereinafter sometimes referred to as Ca + Mg), chlorine content (hereinafter sometimes referred to as Cl), and Cl / ( The Na + K) ratio is shown in Table 3.

In addition, during the period from the start to the end of the desalting treatment, the permeate amount is measured six times over time, and after passing through the desalted whey solution and nanofiltration membrane in the stock solution tank at the time of the measurement, the stock solution tank 40 mL each of the retentate liquid in the middle of being returned to and the permeated liquid of the nanofiltration membrane were collected at the same time. Measure the Na content, K content, and chlorine content (all in mmol / 100g solids) of the collected liquid, and the Cl / (Na + K) ratio in the desalted whey solution in the stock solution tank, the above formula The (Na + K) transmittance determined in (3) and the desalting rate determined in the above equation (2) were calculated. The results are shown in Table 4.

As shown in Tables 3 and 4, the pH values of the raw material whey liquid and the desalted whey liquids (I) and (II) are almost unchanged at 6.8 to 6.9. Although the desalted whey solution (II) had a reduced (Na + K) content as compared with the raw material whey, the desalting rate was only 44.0%. The Ca and Mg contents per 100 g of the solid content increased slightly.
As shown in Table 4, in this example in which the raw material whey solution was desalted as it was by nanofiltration, Cl / (in the desalted whey solution (liquid to be treated) subjected to nanofiltration during the desalting treatment. The Na + K) ratio decreased with time, and finally obtained desalted whey solution (II) was 0.02. Along with this, the transmittance of (Na + K) also decreased, and when the desalting rate reached 44%, the (Na + K) transmittance became a remarkably low value of 0.07.
In general, in a desalting treatment using a membrane separation method, the amount of desalting is determined by (permeate amount) × (concentration of salt to be desalted in the permeate). When the amount of permeate per unit time and the concentration of the salt to be desalted in the raw material liquid are the same, if the transmittance is halved, the desalted amount is also halved. The decrease means that the desalting amount per unit permeate is reduced.
Therefore, in this example, even if desalting is continued in an attempt to increase the desalting rate beyond this level, the desalting does not proceed substantially because the transmittance is extremely low. Even if desalting proceeds, it is considered that the desalting does not proceed because the transmittance further decreases as desalting proceeds.

<Comparative Example 2>
The difference between this example and Comparative Example 1 is that the cheese whey powder used as the raw material whey is different, and in the desalting treatment by nanofiltration, the nanofiltration is carried out by the hydrodiafiltration method, and then the water is stopped and It is a point to continue filtration.
Cheese whey powder (protein 12.7%, fat 0.9%, carbohydrate 76.4%, ash content 8.1%, moisture 2.0%) 5.8kg as raw material whey, water was added to this It melt | dissolved and the raw material whey liquid of 105 kg was obtained.
(Desalination by nanofiltration)
The obtained raw material whey solution was desalted in the same manner as in Comparative Example 1 until the permeate amounted to 52.4 kg with a nanofiltration membrane. At this time, the pH of the desalted whey solution (I) in the stock solution tank was 6.8.
Subsequently, nanofiltration was continued by the hydrodiafiltration method in the same manner as in Comparative Example 1, and desalting treatment was performed until the permeate became 38.6 kg. At this time, the pH of the desalted whey solution in the stock solution tank was 6.7.
Thereafter, the addition of water was stopped and nanofiltration was continued to obtain 14.3 kg of permeate (a total of 105.3 kg from the start of the desalting treatment). The liquid in the stock solution tank thus obtained is designated as desalted whey liquid (II). The recovered amount of the desalted whey liquid (II) is 32.9 kg and contains 4.6 kg of solid content.

About raw material whey and desalted whey liquid (II), the composition per 100 g of solid content is shown in Table 5, and the mineral composition per 100 g of solid content is shown in Table 6.
About raw material whey liquid and desalted whey liquid (II), pH, total of Na content and K content per 100 g of solid content, total of Ca content and Mg content per 100 g of solid content, chlorine content, and The Cl / (Na + K) ratio is shown in Table 7.

In addition, during the period from the start to the end of the desalting treatment, the permeate amount was measured five times over time, and Cl / (Na + K) in the desalted whey solution at each measurement was performed in the same manner as in Comparative Example 1. The ratio, (Na + K) permeability, and desalting rate were calculated. The results are shown in Table 8.

As shown in Tables 7 and 8, the pH of the raw material whey solution and the desalted whey solution (II) is almost unchanged at 6.6 to 6.8.
Although the desalted whey solution (II) had a reduced (Na + K) content compared with the raw material whey, the desalting rate was only 44.1%. Ca and Mg contents decreased slightly.
As shown in Tables 7 and 8, in this example in which the raw material whey solution was desalted as it was by nanofiltration, the Cl / (Na + K) ratio immediately after the start of the desalting treatment (permeate amount 1 kg in Table 8) was 0. 5 and finally decreased to 0.03. The (Na + K) transmittance was as low as 0.09 when the desalination rate reached 44.1%.

<Example 1>
The point that this example is significantly different from Comparative Example 2 is that the raw material whey solution was passed through a chlorine-type anion exchange resin before the desalting treatment by nanofiltration.
As the raw material whey, 6.8 kg of the same cheese whey powder as in Comparative Example 2 was used, and water was added to dissolve it to obtain 95 kg of raw material whey liquid.
(Liquid flow to ion exchange resin)
The obtained raw material whey liquid was passed through a 3 L chlorine type anion exchange resin column (Rohm and Haas, product name: IRA402BL) to obtain 94 kg of an ion exchange whey liquid containing 6 kg of a solid content. The liquid flow conditions were a flow rate of 6.4 SV and a liquid flow temperature of 5 to 10 ° C.

(Desalination by nanofiltration)
Of the obtained ion exchange whey liquid, an amount of liquid corresponding to a solid amount of 5.6 kg was collected and added to make a total amount of 106.5 kg. This was desalted under the same conditions as in Comparative Example 2 until the permeate reached 52.4 kg with a nanofiltration membrane. At this time, the pH of the desalted whey solution (I) in the stock solution tank was 6.5.
Subsequently, under the same conditions as in Comparative Example 2, nanofiltration was continued by a hydrodiafiltration method, and desalting was performed until the permeate reached 38.6 kg. At this time, the pH of the desalted whey solution in the stock solution tank was 6.6.
Thereafter, under the same conditions as in Comparative Example 2, water addition was stopped and nanofiltration was continued to obtain 14.3 kg of permeate (a total of 105.3 kg from the start of the desalting treatment). The liquid in the stock solution tank thus obtained is designated as desalted whey liquid (II). The recovered amount of desalted whey liquid (II) is 34.5 kg and contains 4.8 kg of solids.

About raw material whey and desalted whey liquid (II), the composition per 100 g of solid content is shown in Table 9, and the mineral composition per 100 g of solid content is shown in Table 10.
For raw material whey liquid, ion exchange whey liquid and desalted whey liquid (II), pH, total of Na content and K content per 100 g of solid content, total of Ca content and Mg content per 100 g of solid content, Table 11 shows the chlorine content and the (Cl / (Na + K) ratio).

In addition, during the period from the start to the end of the desalting treatment, the permeate amount was measured five times over time, and Cl / (Na + K) in the desalted whey solution at each measurement was performed in the same manner as in Comparative Example 1. The ratio, (Na + K) transmittance, and desalting rate were calculated. The results are shown in Table 12.

As shown in Tables 11 and 12, the pH values of the raw material whey solution, the ion exchange whey solution, and the desalted whey solution (II) are 6.5 to 6.8 and hardly change.
The desalted whey solution (II) has a significantly reduced (Na + K) content and a high desalting rate of 67.8% compared to the raw material whey.
The (Ca + Mg) content in the desalted whey solution (II) is lower than that in Comparative Examples 1 and 2, but the (Ca + Mg) content in the desalted whey solution (II) relative to the (Ca + Mg) content in the raw material whey. The residual ratio (Ca + Mg) expressed as a ratio is 79.9% when calculated from the values in Table 11, which is favorable.
As shown in Tables 11 and 12, the Cl / (Na + K) ratio immediately after the start of the desalting treatment (the permeate amount of 1 kg in Table 12) is high due to the high chloride ion content of the ion exchange whey solution subjected to nanofiltration. Was as high as 0.88, and finally decreased only to 0.37. The (Na + K) permeability was as high as 0.43 in the desalted whey solution (II) in which the desalting rate reached 67.8%.

<Example 2>
The difference between this example and Example 1 is that, in nanofiltration after passing through the ion exchange resin, desalting is first performed under conditions to obtain a 3-fold concentrated solution, and then desalted by hydrodiafiltration. This is the point where salt treatment was performed.
Cheese whey powder (13.2% protein, 0.9% fat, 76.0% carbohydrates, 7.9% ash, 2.1% moisture) as a raw material whey was dissolved in 185 kg by adding water to 185 kg A 5 kg raw material whey solution was prepared. (Liquid flow to ion exchange resin)
The obtained raw material whey liquid was passed through a 10 L chlorine-type anion exchange resin column (Rohm and Haas, product name: IRA402BL). 1-No. It was obtained by dividing into three. The flow conditions were a flow rate of 6.0 SV and a flow temperature of 5 to 10 ° C. No. 1-No. The pH of the ion exchange whey solution of No. 3 was 6.5. Table 13 shows the liquid amount and solid amount of each liquid, and the chlorine content per 100 g of the solid content.

Next, in the same nanofiltration membrane as in Comparative Example 1, no. 1-No. While the ion exchange whey solution of 3 is sequentially added, the desalting treatment is carried out while operating the one-way system without returning the retentate solution to the stock solution tank, and the concentration factor is tripled, and the water in the device is added. As a result, 78.0 kg of a retentate solution (desalted whey solution) containing 12.2 kg of a solid content was obtained.
The method of charging is No. in the raw material tank. No. 1 immediately before the liquid of 1 was exhausted. No. 2 was added, and No. 2 was similarly applied. No. 2 immediately before the liquid of No. 2 runs out. 3 liquids were added. No. in the raw material tank. The operation of the apparatus was stopped immediately before the liquid 3 was exhausted.
For example, when the raw material whey solution is supplied to a membrane module equipped with a nanofiltration membrane at 3 L / min, the retentate solution (desalted whey solution) is supplied at a rate of 1 L / min. The removal rate of the retentate liquid and the permeated liquid can be set to a ratio of 1: 2 such that the permeated liquid is extracted from the membrane module at a rate of 2 L / min.
The pH of the 3-fold concentrated desalted whey solution (retentate solution) thus obtained, the total of Na content and K content per 100 g of solid content, the total of Ca content and Mg content per 100 g of solid content, and chlorine content The amounts and the Cl / (Na + K) ratio are shown in Table 17.

No. 3 times over time until 18.0 kg of retentate solution (desalted whey solution) is obtained after feeding 1 and the raw material whey solution, retentate solution (desalted whey solution), permeate in the stock solution tank 40 mL of each was collected simultaneously. The first sampling is No. in the raw material tank. Immediately before the liquid of 1 is exhausted, the second sampling is No. in the raw material tank. Immediately before the liquid of No. 2 disappears, the third sampling is No. in the raw material tank. Each of the three liquids was being separated and was performed immediately before the operation of the apparatus was stopped.
In the same manner as in Comparative Example 1, the Cl / (Na + K) ratio and (Na + K) permeability in the raw material whey liquid (processed liquid) in the stock solution tank were calculated. The results are shown in Table 14.
When the desalting rate was determined in the same manner as in Comparative Example 1, it was 55%.

Subsequently, the three-fold concentrated desalted whey solution obtained above was subjected to nanofiltration with the same nanofiltration membrane, and then returned to the stock solution tank while the retentate solution was returned to the stock solution tank. Desalting was performed until 6 kg was obtained. The liquid in the stock solution tank thus obtained is designated as desalted whey liquid (II). The recovered amount of desalted whey liquid (II) is 71.1 kg and contains 10.8 kg of solid content.

About raw material whey and desalted whey liquid (II), the composition per 100 g of solid content is shown in Table 15, and the mineral composition per 100 g of solid content is shown in Table 16.
About raw material whey liquid, said 3 times concentration desalted whey liquid and desalted whey liquid (II), pH, total of Na content and K content per 100 g of solid content, Ca content and Mg content per 100 g of solid content The total amount, chlorine content, and Cl / (Na + K) ratio are shown in Table 17.

In addition, while measuring the amount of permeate four times over the course from the start to the end of nanofiltration by the hydrodiafiltration method, desalting in the raw material tank at each measurement in the same manner as in Comparative Example 1 The Cl / (Na + K) ratio, (Na + K) permeability, and desalting rate in the whey solution were calculated, respectively. The results are shown in Table 18.

As shown in Tables 17 and 18, the raw material whey solution, No. 1-No. The pH of No. 3 ion exchange whey solution, 3 times concentrated desalted whey solution, and desalted whey solution (II) is 6.3 to 6.8, and hardly changes.
The desalted whey liquid (II) has a significantly reduced (Na + K) content as compared with the raw material whey, and the desalting rate is 76.2%, which is higher than that of Example 1.
When calculated from the values in Table 17, the residual ratio of (Ca + Mg) in the desalted whey solution (II) is 88.6%, which is favorable.
As shown in Tables 17 and 18, the Cl / (Na + K) ratio immediately after the start of the desalting treatment (first time in Table 14) is 1 because the chloride ion content of the ion exchange whey solution used for nanofiltration is high. It was as high as .12, and finally decreased only to 0.56 (permeate amount of 77.6 kg in Table 18). The (Na + K) permeability was as high as 0.5 even when the desalting rate reached 76.2%.

<Example 3>
A desalted whey solution was produced in the same procedure as in Example 1. That is, the desalting conditions by nanofiltration are the same as in Comparative Example 2. In this example, the amount of ion exchange resin used was changed from 3 L to 5 L, so that the chlorine content in the ion exchange whey liquid was higher than in Example 1.
As a raw material whey, water was added to and dissolved in 6.75 kg of the same cheese whey powder as in Comparative Example 2 to obtain a 95 kg raw material whey solution.
(Liquid flow to ion exchange resin)
The obtained raw material whey liquid was passed through a 5 L chlorine-type anion exchange resin column (Rohm and Haas, product name: IRA402BL) to obtain 88.1 kg of an ion exchange whey liquid containing 5.74 kg of a solid content. It was. The liquid flow conditions were a flow rate of 6.4 SV and a liquid flow temperature of 6 to 10 ° C.

(Desalination by nanofiltration)
Water was added to the obtained ion exchange whey solution to make a total amount of 105 kg. This was desalted under the same conditions as in Comparative Example 2 until the permeate reached 52.4 kg with a nanofiltration membrane. At this time, the pH of the desalted whey solution (I) in the stock solution tank was 6.4.
Subsequently, nanofiltration was continued by a hydrodiafiltration method under the same conditions as in Comparative Example 2, and desalting treatment was performed until the permeate reached 38.6 kg. At this time, the pH of the desalted whey solution in the stock solution tank was 6.5.
Thereafter, the addition of water was stopped and nanofiltration was continued to obtain 14.3 kg of permeate (a total of 105.3 kg from the start of the desalting treatment). The liquid in the stock solution tank thus obtained is designated as desalted whey liquid (II). The recovered amount of the desalted whey liquid (II) is 33.1 kg and contains 4.8 kg of solids.

About raw material whey and desalted whey liquid (II), the composition per 100 g of solid content is shown in Table 19, and the mineral composition per 100 g of solid content is shown in Table 20.
For raw material whey liquid, ion exchange whey liquid and desalted whey liquid (II), pH, total of Na content and K content per 100 g of solid content, total of Ca content and Mg content per 100 g of solid content, Table 21 shows the chlorine content and the (Cl / (Na + K) ratio).

In addition, during the period from the start to the end of the desalting treatment, the permeate amount was measured five times over time, and Cl / (Na + K) in the desalted whey solution at each measurement was performed in the same manner as in Comparative Example 1. The ratio, (Na + K) transmittance, and desalting rate were calculated. The results are shown in Table 22.

As shown in Tables 21 and 22, the pH values of the raw material whey liquid, ion exchange whey liquid, and desalted whey liquid (II) are 6.4 to 6.8 and hardly change.
The desalted whey solution (II) has a significantly reduced (Na + K) content compared to the raw material whey, and the desalting rate is 73.9%, which is higher than that of Example 1.
When calculated from the values in Table 21, the residual ratio of (Ca + Mg) in the desalted whey solution (II) is 69.5%, which is slightly lower than Example 1 but good.
As shown in Tables 21 and 22, the Cl / (Na + K) ratio immediately after the start of the desalting treatment (permeated liquid amount 1 kg in Table 18) because the ion exchange whey solution used for nanofiltration has a high chloride ion content. Was as high as 1.03, and finally decreased only to 0.56 (permeated liquid amount of 105.3 kg in Table 22). The (Na + K) permeability was as high as 0.53 even when the desalination rate reached 73.9%.

<Comparison between Example 3 and Comparative Example 2>
Table 23 shows the raw material whey used in Example 3 and Comparative Example 2, and the desalted whey solution obtained in each example, the total of Na content and K content per 100 g of solid content, 100 g of solid content. The total of Ca content per Mg and Mg content, chlorine content, and (Cl / (Na + K) ratio) are collectively shown.
FIG. 1 is a graph showing the relationship between the accumulated permeate amount and the desalination rate (%) of (Na + K) based on the results of Example 3 and Comparative Example 2.

As shown in Table 23, Cl / (Na + K) in Example 3 in which the raw material whey liquid was passed through a chlorine-type anion exchange resin before the desalting treatment by nanofiltration was compared to Comparative Example 2. The ratio is remarkably large and the (Na + K) content is small.
In addition, as shown in FIG. 1, even though the accumulated permeate amounts in the nanofiltration step are the same, Example 3 has a higher (Na + K) desalination rate than Comparative Example 2, and unit permeation Desalination efficiency per liquid volume was greatly improved.

<Comparative Example 3>
The difference between this example and Example 3 is that the raw material whey liquid is not passed through the chlorine-type anion exchange resin, but instead a liquid obtained by adding CaCl ₂ · 2H ₂ O to the raw material whey liquid is subjected to nanofiltration. It is a point that was subjected to. The desalting conditions by nanofiltration are the same as in Comparative Example 2.

As raw material whey, use cheese whey powder (protein 12.3%, fat 1.1%, carbohydrate 76.4%, ash 7.4%, moisture 1.9%) 5.83kg, add water to this An aqueous solution in which 200 g of calcium chloride dihydrate (CaCl ₂ · 2H ₂ O) was further dissolved in water was added to and mixed with the dissolved raw material whey solution to obtain 105 kg of calcium chloride-added whey solution.

(Desalination by nanofiltration)
The obtained calcium chloride-added whey solution was desalted under the same conditions as in Comparative Example 2 with a nanofiltration membrane until the permeate amounted to 52.4 kg. At this time, the pH of the desalted whey solution (I) in the stock solution tank was 6.2.
Subsequently, nanofiltration was continued by a hydrodiafiltration method under the same conditions as in Comparative Example 2, and desalting treatment was performed until the permeate reached 38.6 kg. At this time, the pH of the desalted whey solution in the stock solution tank was 6.2.
Thereafter, the addition of water was stopped and nanofiltration was continued to obtain 14.3 kg of permeate (a total of 105.3 kg from the start of the desalting treatment). The liquid in the stock solution tank thus obtained is designated as desalted whey liquid (II). The recovered amount of desalted whey liquid (II) is 33.0 kg and contains 5.0 kg of solid content.

About raw material whey and desalted whey liquid (II), the composition per 100 g of solid content is shown in Table 24, and the mineral composition per 100 g of solid content is shown in Table 25.
About raw material whey solution, calcium chloride added whey solution and desalted whey solution (II), pH, total of Na content and K content per 100 g of solid content, total of Ca content and Mg content per 100 g of solid content Table 26 shows the chlorine content and the Cl / (Na + K) ratio.

Also, the Cl / (Na + K) ratio, (Na + K) permeability, and desalting rate in the desalted whey solution at the time immediately after the start of desalting treatment (permeate amount 1 kg) and at the end thereof were calculated. The results are shown in Table 27.

<Measurement of permeation flux>
About Example 3 and Comparative Example 3, the time-dependent change of the permeation flux (unit: L / min) per unit membrane module from the start to the end of the desalting process by nanofiltration was examined. The result is shown in FIG. The vertical axis in FIG. 2 represents the permeation flux (unit: L / min) per membrane module (membrane area 7.4 m ² ), and the horizontal axis represents the integrated value of the permeate amount.

As shown in Tables 26 and 27, since calcium chloride was added in Comparative Example 3, the content of (Ca + Mg) in the desalted whey solution (II) was significantly increased as compared with the raw material whey. Further, (Na + K) transmittance and desalting rate are slightly inferior to those of Example 3.
Specifically, in Comparative Example 3, since calcium chloride was added, the Ca content in the desalted whey solution (II) was 30.7 mmol / 100 g solid, which was about three times that of the raw material whey. Calcium is an important nutrient, but an excessive increase in Ca content is not always acceptable. For example, when using whey in formula milk, if the Ca content is too high, it is necessary to limit the amount used.

In addition, as shown in FIG. 2, although nanofiltration was performed under the same conditions as in Example 3, Comparative Example 3 to which calcium chloride was added had a permeation flux per unit membrane module of about 1/2. And much smaller. If the permeation flux is halved, the amount of liquid that can be processed in the same area is halved, and if the membrane area is the same, twice the time required to obtain the same permeate flow rate is required. Means.

<Example 4>
In this example, a nanofiltration membrane different from those in Examples 1 to 3 was used.
Cheese whey powder (protein 12.1%, fat 1.1%, carbohydrate 77.2%, ash 7.8%, moisture 1.8%) 6.1 kg was dissolved in water to make 85 kg of raw whey solution . This raw material whey solution was passed through a 6 L chlorine type anion exchange resin column (Rohm and Haas, product name: IRA402BL) to obtain 95.1 kg of ion exchange whey solution containing 5.82 kg of solid content. The liquid flow conditions were a flow rate of 6.4 SV and a liquid flow temperature of 5 to 10 ° C.

The total amount was made 106 kg by adding water to this ion exchange whey solution. This was subjected to desalting with a nanofiltration membrane (Duratherm Pro NF3840HR: manufactured by GE Water & Process Technologies) in a batch concentration manner while returning the retentate solution to the stock solution tank until 66.6 kg of permeate was obtained. The liquid in the stock solution tank at this time is defined as desalted whey liquid (I). The pH of the desalted whey solution (I) was 6.6.
Thereafter, nanofiltration was continued by a hydrodiafiltration method, and desalting was performed until the permeate reached 33.3 kg (total 99.9 kg from the start of desalting). The liquid in the stock solution tank thus obtained is designated as desalted whey liquid (II). The recovered amount of desalted whey liquid (II) is 32.9 kg and contains 4.7 kg of solid content.
For raw material whey liquid, ion exchange whey liquid and desalted whey liquid (II), pH, total of Na content and K content per 100 g of solid content, total of Ca content and Mg content per 100 g of solid content, Table 28 shows the chlorine content and the Cl / (Na + K) ratio.

As shown in Table 28, the pH values of the raw material whey liquid, the ion exchange whey liquid, and the desalted whey liquid (II) are 6.4 to 6.8, and hardly change.
The desalted whey solution (II) has a significantly reduced (Na + K) content and a high desalting rate of 75.9% compared to the raw material whey.
The residual ratio of (Ca + Mg) in the desalted whey solution (II) is 78.8% when calculated from the values in Table 28, which is favorable.
The ion exchange whey solution used for nanofiltration had a high chloride ion content, and the Cl / (Na + K) ratio decreased only from 1.01 to 0.94 in the desalting process.

According to the method of the present invention, it is possible to efficiently produce a desalted whey in which sodium and potassium are sufficiently reduced while suppressing reduction of the contents of calcium and magnesium contained in the raw material whey.

Claims (7)

1. A method for producing desalted whey,
   Including passing a solution to be subjected to desalting treatment through an ion exchange resin before being desalted, and subjecting the liquid to be treated to desalting by a membrane separation method. ,
   Here, the ion exchange resin comprises an anion exchange resin,
   The method using at least a chlorine-type anion exchange resin as the anion exchange resin.
2. The liquid to be treated for the desalting treatment is a raw material whey, the pH of the raw material whey liquid is in the range of 6-7, and the pH of the effluent from the anion exchange resin is 6-7. The method for producing a desalted whey according to claim 1.
3. The method for producing desalted whey according to claim 1 or 2, wherein the membrane separation method is a nanofiltration method.
4. The molar ratio (chlorine / (sodium + potassium)) of the chlorine content to the total value of the sodium content and the potassium content of the liquid to be subjected to the desalting treatment is maintained at 0.35 or more. Item 4. The method for producing desalted whey according to any one of Items 1 to 3.
5. In the effluent from the chlorine-type anion exchange resin, the molar ratio of the chlorine content to the total value of the sodium content and the potassium content (chlorine / (sodium + potassium)) is 0.8 or more. The method for producing desalted whey according to any one of claims 1 to 4.
6. The (Ca + Mg) residual rate obtained by the following formula (1) in the desalted whey is 60% or more, and the desalting rate obtained by the following formula (2) is 60% or more. The manufacturing method of desalted whey as described in any one of Claims.
   (Ca + Mg) residual rate (unit:%) = {(total of Ca content and Mg content of desalted whey) / (total of Ca content and Mg content of raw whey solution)} × 100 (1) (In Formula 1, the Ca content is the content of calcium contained per 100 g of solid content, the Mg content is the content of magnesium contained per 100 g of solid content, and the unit is mmol / 100 g solid. is there.)
   Desalination rate (unit:%) = {{(total of Na content and K content of raw material whey liquid) − (total of Na content and K content of desalted whey liquid)} / (Na of raw whey liquid) Sum of content and K content)} × 100 (2)
   (In Formula 2, Na content is the content of sodium contained per 100 g of solid content, K content is the content of potassium contained per 100 g of solid content, and all units are in mmol / 100 g solids. is there.)
7. The method for producing desalted whey according to any one of claims 1 to 6, wherein the desalted whey is for formula milk powder.

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