JP5835726B2 - Process for producing desalted milk, desalted and defatted milk, desalted concentrated milk and desalted and defatted concentrated milk, and desalted milk powder and desalted and defatted milk powder - Google Patents

Description

  TECHNICAL FIELD The present invention relates to desalted milk and desalted skim milk, and methods for producing these, and in particular, by using membrane separation technology, stable desalted milk and desalted skim milk for a long period of time. The present invention relates to a production method to be produced, and a quality-degraded desalted milk and a desalted skim milk produced thereby.

  Membrane separation technology is adopted as one of the methods for removing ions from milk. In the dairy industry, various types of milk protein / peptide raw materials for infant formula milk, WPC (whey protein concentrate), TMP (milk protein concentrate), etc. are used for the recovery and effective use of cheese whey produced as a by-product during cheese manufacture. It is widely used in the production of protein raw materials for food and drink, dairy products such as natural cheese and yogurt, and component-modified milk and concentrated milk.

  Various membranes for membrane separation exist and have different characteristics.

  RO (Reverse Osmosis) membrane removes only water from milk and is mainly used for concentration.

  NF (Nanofiltration) membranes are used for the purpose of removing salty taste by partial desalting because they pass through monovalent ions such as sodium and potassium. Since the treatment method using the NF membrane can easily reduce monovalent minerals such as sodium and potassium and simultaneously remove water, the load in the concentration and drying process can be reduced. It is said to be an efficient method.

  Therefore, conventionally, by using a NF membrane, monovalent metal salts such as water and sodium in milk or milk material are permeated and separated, and the non-fat milk solid content and the Ca / Na concentration ratio are adjusted, It has been proposed to adjust the non-fat milk solids content and the Ca / Na concentration ratio by permeating and separating moisture by using an RO membrane and mixing it with milk or milk material that has been treated with an NF membrane. (Patent Document 1).

  Also, NF method using NF membrane and desalting milk as it is, Diafiltration (DF) method of adding water to milk concentrated by filtration through NF membrane, and further filtering through NF membrane, raw material A method has been proposed in which milk is filtered through an NF membrane to remove only monovalent minerals such as sodium and potassium, and then concentrated and spray-dried to obtain a low mineral milk powder (Patent Document 2).

JP 2002-253116 A JP-A-8-266221

  The desalination rate when separating sodium and potassium from raw milk (raw milk) using membrane separation technology cannot be monitored online, and is generally confirmed by analysis after the end of production. That is, when desalinating from raw milk (raw milk) using membrane separation technology in the prior art, desalted milk that has been desalted after all raw milk has been passed through the desalting process is stored in a storage tank, etc. A method of checking the composition of sodium and potassium after storing the solution and making the concentration and composition uniform by stirring or the like has been adopted.

  In such a conventional method, there is a possibility that the desalination rate varies depending on the treatment (batch), and a new treatment such as further desalination treatment is required according to the measured desalination rate. There was also a concern. Thus, there has been a problem that desalted milk that has been desalted from raw milk by the same process cannot be stably supplied.

  Moreover, when separating sodium and potassium from raw milk (raw milk) using membrane separation technology, it was necessary to set the pressure required on the high concentration side when the pressure was controlled in one section, and the membrane was likely to be clogged .

  When the membrane is clogged, pipe cleaning (CIP) is performed, but when it is restarted, it is difficult to completely return the desalting conditions to the original conditions, and there is a difference in the desalting rate of the product before and after CIP. was there.

  In other words, when desalting raw milk (raw milk) is processed with a single desalting membrane, especially when a line design is used to process a large amount of raw milk at once, blocking the desalting membrane In order to produce desalted processed milk with a constantly designed desalination rate from raw milk, it is necessary to use a new (freshly) membrane every time one batch of raw milk is processed. There is no technical proposal to solve this problem.

  On the other hand, for example, the degree of desalting from raw milk affects the flavor of raw milk itself, dairy products using raw milk, and food and drink using the dairy products. For example, it is also known that the salty taste of the raw milk itself is reduced by desalting the raw milk, the milk flavor is relatively increased, and the good flavor of the milk is increased. For this reason, desalinized milk that has been desalted from raw milk at a stable desalting rate, and dairy products using the desalted milk have been demanded from the market.

  From the above background, the present invention uses a membrane separation technique to produce a desalinized milk and a desalted skim milk powder with stable quality for a long time, and a stable desalted product produced thereby. The object is to propose salt-treated milk and desalted skim milk powder.

The invention described in claim 1
After the first membrane concentration treatment is performed on the raw material milk using the nanofiltration membrane, the raw material milk after the first membrane concentration is diluted, and again using the nanofiltration membrane By performing the second membrane concentration treatment, the sodium-equivalent salt content after the second membrane concentration treatment is lower than the sodium-equivalent salt content in the raw milk, A desalinized milk production method for continuously producing a desalination rate at a predetermined value for 12 hours or more ,
Permeation flux in the first membrane concentration treatment and the second membrane concentration treatment: F (kg / m ² / h), solid content concentration of the raw milk and before the second membrane concentration Solid content concentration: between TS (wt%)
F <22-0.8TS
(However, F <9.2 and TS <25.8)
This is a method for producing desalted milk, wherein the relationship is established .

The invention according to claim 2
The raw material milk is any of animal milk that has not undergone a reduction step, processed milk produced by reducing a dairy product that is a processed product of the animal milk, and plant-derived milk. It is a manufacturing method of desalinized milk described.

The invention described in claim 3
The method for producing desalted milk according to claim 1 or 2, wherein the raw milk is a whole fat type .

The invention according to claim 4
The method for producing desalted milk according to claim 1 or 2, wherein the raw milk is defatted .

The invention according to claim 5
Permeation flux in the first membrane concentration treatment and the second membrane concentration treatment: F (kg / m ² / h), solid content concentration of the raw milk and before the second membrane concentration Solid content concentration: between TS (wt%)
F <22.3-TS
(However, F <10.1 and TS <18.9)
The method for producing desalted milk according to claim 4, wherein the relationship is established .

The invention described in claim 6
After the first membrane concentration treatment is performed on the raw material milk using the nanofiltration membrane, the raw material milk after the first membrane concentration is diluted, and again using the nanofiltration membrane By performing the membrane concentration treatment for the second time, the desalinized milk for continuously producing desalted milk having a salt content reduced by 40% or more in terms of sodium as compared with the raw material milk for 12 hours or more. A manufacturing method comprising:
Permeation flux in the first membrane concentration treatment and the second membrane concentration treatment: F (kg / m ² / h), solid content concentration of the raw milk and before the second membrane concentration Solid content concentration: between TS (wt%)
F <22-0.8TS
(However, F <9.2 and TS <25.8)
This is a method for producing desalted milk, characterized in that the above relationship is established .

The invention described in claim 7
The raw milk is claim 6, wherein the animal milk that has not undergone the reduction step, processed milk made by reducing the dairy is a processed product of the animal milk to be either milk of vegetable origin serial is a manufacturing method of desalting milk mounting.

The invention described in claim 8
The method for producing desalted milk according to claim 6 or 7, wherein the raw milk is a whole fat type .

The invention according to claim 9
The method for producing desalted milk according to claim 6 or 7, wherein the raw milk is defatted .

The invention according to claim 10 is:
Permeation flux in the first membrane concentration treatment and the second membrane concentration treatment: F (kg / m ² / h), solid content concentration of the raw milk and before the second membrane concentration Solid content concentration: between TS (wt%)
F <22.3-TS
(However, F <10.1 and TS <18.9)
The method for producing desalted milk according to claim 9, wherein the relationship is established .

The invention according to claim 11
In the desalting concentration step in the first membrane concentration treatment and the second membrane concentration treatment, the desalting concentration step is performed with the permeation flux: F (kg / m ² / h) being constant. In addition, the continuous operation is performed so that the operation pressure does not increase with the operation time during the desalting and concentration step, and the desalinized milk according to any one of claims 1 to 10 is produced. Is the method .

The invention according to claim 12
12. The dewatering according to claim 11, wherein the operating pressure is kept constant during the desalting and concentration step, or the operating pressure is controlled to be within a predetermined range during the desalting and concentration step. This is a method for producing salt-treated milk .

The invention according to claim 13
The desalinized milk produced by the desalinized milk production method according to any one of claims 4, 5, 9, and 10 is a desalted and skimmed milk. Is the method .

The invention according to claim 14
A method for producing any one desalination process to remove water from the desalination process milk desalted and concentrated milk produced by the manufacturing method of the milk according to claims 1-12.

The invention according to claim 15 is:
13. to remove moisture from the desalination degreased milk produced by the manufacturing method of desalination degreasing milk wherein the process for producing desalted defatted concentrated milk.
The invention according to claim 16
A method for producing desalted powdered milk by removing water from the desalted milk produced by the method for producing desalted milk according to claim 1, and pulverizing it .
It is.
The invention described in claim 17
A method for producing demineralized skim milk powder by removing moisture from the desalted and degreased processed milk produced by the method for producing demineralized and degreased milk according to claim 13.
It is.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method which manufactures demineralized milk and demineralized skim milk powder with which quality was stabilized continuously for a long time, and the demineralized milk and demineralized skim milk powder which were manufactured stably by this are provided. be able to.

The figure which shows the time-dependent change of the refractive sugar degree (%) of the concentrate in the continuous operation which performed the process which membrane-concentrates skim milk using a nanofiltration (NF) film | membrane continuously for a maximum of 12 hours. The figure showing the time-dependent change of the operation pressure in the several membrane concentration continuous treatment driving | operation with which the operation conditions in the continuous operation are represented in Table 2. The figure showing the area | region considered to be continuous for 12 hours from the relationship between permeation | transmission flux (kg / m < ² > / h) and solid content concentration (weight%) based on the result of the continuous operation of Table 2 and FIGS. The figure which shows the time-dependent change of the refractive sugar degree (%) of the concentrate in the continuous operation which performed the process which membrane-concentrates raw milk using a nanofiltration (NF) film | membrane continuously for a maximum of 12 hours. The figure showing the time-dependent change of the operation pressure in the several membrane concentration continuous process driving | operation with which the operation conditions in the continuous operation are represented in Table 3. Based on the results of continuous operation shown in Table 3 and FIGS. 4 to 5, a diagram showing an area considered to be possible for 12 hours from the relationship between the permeation flux (kg / m ² / h) and the solid content concentration (% by weight). .

  The inventors of the present invention have made extensive studies in order to achieve the above object, and have obtained the following knowledge.

That is, when the raw milk is concentrated in a membrane and desalted, the membrane is concentrated while setting the flow rate (permeation flux) (kg / m ² / h) of the permeate per nanofiltration membrane area to a predetermined range, Dilution treatment is then performed, and further, membrane concentration is performed while setting the flow rate (permeation flux) (kg / m ² / h) of the permeate per nanofiltration membrane area within a predetermined range, so that a long time (12 hours or more) ) It has been found that desalted milk can be stably produced while maintaining a predetermined desalting rate (decrease of 40% or more in terms of sodium) continuously.

  In addition, by adopting the method for producing desalted processed milk of the present invention, not only simply desalting raw material milk, but also continuously producing desalted processed milk as designed as necessary. It is possible to adjust the desalination rate according to the completed desalted state, such as desalting again after desalination treatment of all raw milk and addition of raw milk again after desalting treatment of all raw milk. The risk of complications is reduced, and efficient production of desalted and concentrated milk can be expected.

  In the method for producing desalted milk proposed by the present invention, after the first membrane concentration treatment is performed on raw milk using a nanofiltration membrane, the raw milk after the first membrane concentration is processed. By diluting and again performing the second membrane concentration treatment using the nanofiltration membrane, the sodium equivalent salt content after the second membrane concentration treatment is reduced to the sodium equivalent in the raw milk. Desalinated milk that is lower than the salt content is continuously produced for 12 hours or more while maintaining the desalination rate at a predetermined value, or the salt content is 40 in comparison with the raw material milk in terms of sodium. % Desalted milk that has been reduced by at least 12% is produced continuously for 12 hours or more.

  In the present invention, it is preferable that the first and second membrane concentration treatments are performed with a predetermined permeation flux using the nanofiltration membrane having a predetermined range of membrane area. Thereby, desalted milk can be stably produced while maintaining a predetermined desalting rate (decrease of 40% or more in terms of sodium) continuously for a long time (12 hours or more).

Here, the permeation flux (kg / m ² / h) is the flow rate of the permeate per nanofiltration membrane area. The flow rate (kg ² / h) of raw milk that permeates the nanofiltration membrane having a membrane area (m ² ) in a predetermined range, and the raw material that is diluted after the first membrane concentration and used for the second membrane concentration The milk flow rate (kg ² / h) is obtained by dividing the milk flow area (m ² ) by the nanofiltration membrane, respectively.

  Here, the origin of the raw material milk is not particularly limited, and examples thereof include animal milk (such as milk, sheep milk, goat milk, and buffalo milk) and plant-derived milk (soy milk). The raw material milk is not particularly limited as long as it is liquid, such as raw milk that has not undergone a reduction step, and processed milk that is produced by reducing dairy products (fat dry milk, skim milk, butter, cream, condensed milk, etc.).

  In addition, since raw milk can be desalted with a nanofiltration membrane if it is liquid, it goes without saying that it is not limited to any of the full fat type, degreased type, and fat-enriched type.

  Furthermore, various foods and food additives for enhancing the flavor and nutritional value of the raw material milk can be arbitrarily added as long as the raw material milk is liquid.

  The first membrane concentration treatment according to the present invention is not particularly limited as long as it is a membrane concentration treatment having a function of permeating and condensing monovalent cations such as sodium and potassium and moisture. The membrane treatment using a nanofiltration (NF) membrane is preferable. A commercially available nanofiltration membrane can be used, but the average salt removal rate is 90% or higher, preferably 95% or higher, more preferably 97% or higher. The average salt removal rate of the translation membrane was 97% to 99%.

  The means for diluting in the production method of the present invention is not particularly limited as long as it dilutes the processed product (concentrated milk) after the first membrane concentration treatment.

  For example, after the first membrane concentration treatment, the raw material water is added to the processed product (concentrated milk) after the first membrane concentration treatment, or the raw water is desalted and then diluted. If the composition of this processed material (concentrated milk) becomes thin, it will not specifically limit.

  In addition to the raw water, the permeate (the solution containing monovalent cations such as sodium and potassium permeated from the raw milk and water) that was generated in the first membrane concentration treatment was desalted. You can use everything. Examples of the desalting treatment here include a method using a reverse osmosis membrane treatment such as an RO membrane, a method of performing an electrodialysis treatment, a method of performing an ion exchange treatment such as an ion exchange column, and the like. Is not to be done.

  The second membrane concentration treatment in the production method of the present invention described above is not particularly limited as long as it is a membrane concentration treatment having a function of permeating and condensing monovalent cations such as sodium and potassium and moisture. Absent. The membrane treatment using a nanofiltration (NF) membrane is preferable. A commercially available nanofiltration membrane can be used, but the average salt removal rate is 90% or higher, preferably 95% or higher, more preferably 97% or higher. The average salt removal rate of the translation membrane was 97% to 99%.

In the production method of the present invention described above, the desalinized milk is continuously produced for 12 hours or more while maintaining the desalination rate at a predetermined value. In the continuous production of desalted milk that has been reduced by 40% or more for 12 hours or longer, the permeation flux in the first and second membrane concentration treatments: F (kg / m ² / h ) And the solid content concentration of the raw material milk and the solid content concentration before the film concentration: TS (% by weight) is desirably established.

As described above, the first and second membrane concentration treatments are performed by using the nanofiltration membrane having a membrane area within a predetermined range and with a predetermined permeation flux. Salt-treated milk is produced continuously for 12 hours or more while maintaining the desalination rate at a predetermined value, or the salt content is reduced by 40% or more in terms of sodium compared to the raw milk. Milk can be produced continuously for 12 hours or more. Furthermore, the permeation flux: F (kg / m ² / h) in the first and second membrane concentration treatments, the solid content concentration of the raw material milk and the solid content before the membrane concentration is performed. Concentration: By producing a predetermined relationship with TS (% by weight), desalted milk is continuously produced for 12 hours or more while maintaining the desalination rate at a predetermined value, or sodium equivalent Thus, it is possible to more stably produce desalted milk having a salt content reduced by 40% or more compared to the raw material milk for 12 hours or more.

In this case, the permeation flux in the first and second membrane concentration processes: F (kg / m ² / h), the solid content concentration of the raw milk and the solid content concentration before the membrane concentration: TS The relationship between (% by weight) can be appropriately set in consideration of the target desalination rate in each treatment.

  For example, according to the study by the inventors of the present application, when desalinating skim milk, the relationship of F <22.3-TS (where F <10.1 and TS <18.9) is established. It has been confirmed that it is desirable.

  In this case, when F> 10.1 or TS> 18.9, the membrane is blocked as the operation time becomes longer, so that the pressure in the tube is increased and stable continuous production becomes difficult. Further, in the case of permeation flux F> 22.3-TS, the pressure in the pipe increases, and stable continuous production becomes difficult.

  In addition, when the said relationship (F <22.3-TS) is materialized, the said raw material milk can be processed with the processing amount of 20 t / h.

For example, in this case, the nanofiltration membranes used for the first membrane concentration treatment and the second membrane concentration treatment are the same, and the total membrane area is 1800 m ² , Desalted and concentrated to a solid content of 9.4% to 16% by membrane concentration, diluted with diluted water to a desalted and concentrated milk with a solid content of 16% to a solid content of 9.4%, and solidified by the second membrane concentration. By desalting and concentrating again from 9.4% to 16%, 40% desalting can be achieved in terms of sodium. By designing to perform these steps in series, it becomes possible to produce desalted and defatted (concentrated) milk having a stable desalting rate for 12 hours or more.

  On the other hand, when the raw milk (whole milk) is desalted, according to the study by the present inventors, F <22-0.8TS (however, F <9.2 and TS <25.9). It has been confirmed that the above relationship is desirable.

  In this case, when F> 9.2 or TS> 25.9, the membrane is blocked as the operation time becomes longer, so that the pressure in the tube is increased and stable continuous production becomes difficult. In addition, when the permeation flux F> 22-0.8TS, the pressure in the pipe increases, and stable continuous production becomes difficult.

  In addition, when the said relationship (F <22-0.8TS) is materialized, the said raw material milk can be processed with the processing amount of 20 t / h and 14 t / h.

In this case, the nanofiltration membranes used for the first membrane concentration treatment and the second membrane concentration treatment are the same, and both have a membrane area of 1800 m ² and the first membrane concentration treatment. Desalted and concentrated from 12.8% to 22.6% solids, diluted 22.6% desalted and concentrated milk with diluted water to 12.8% solids, and concentrated for the second time. By desalting and concentrating again from 12.8% to 22.6% solid content, 40% desalting can be achieved in terms of sodium. By designing these steps in a series, desalted (concentrated) milk having a stable desalination rate for 12 hours or more can be produced.

  Furthermore, in the skim milk and raw milk, within the range where the relationship between the permeation flux F and the total solid content TS is established, the process of effectively using one nanofiltration membrane treatment facility and repeating the membrane treatment and liquid storage It goes without saying that it is possible to produce a desalted (defatted) concentrated milk having a stable desalting rate for 12 hours or more after the final nanofiltration membrane treatment. It is expected that the space occupied by the membrane equipment will be improved.

In this case, the nanofiltration membrane used for the membrane concentration treatment has a membrane area of 648 m ² , stores liquid after the first membrane concentration, and then performs the second membrane concentration to obtain a solid content of 12 Desalted and concentrated from 8% to 25.6%, diluted 25.6% of desalted and concentrated milk to 12.8% in diluted water, and stored after the third membrane concentration. Next, the fourth concentration of the membrane is desalted and concentrated from 12.8% to 25.6% solids, and the second concentration of the membrane is again desalted from 12.8% to 22.6% solids. Concentration makes it possible to desalinate 50% in terms of sodium. By designing these steps, it is possible to produce desalted and defatted (concentrated) milk having a stable desalting rate for 12 hours or more after the fourth membrane concentration treatment.

  In the production method of the present invention, when the permeation flux is kept constant in the desalting and concentration step by membrane treatment, the operation pressure does not increase with the operation time, and is constant or within a predetermined range. Production of desalted (defatted) concentrated milk with a desalting rate of is desirable in that the risk of blockage of the membrane is reduced.

  In the production method of the present invention, the treatment temperature of the raw material milk is not particularly limited, but when the raw material milk before sterilization is treated, it is desirable to treat it at a low temperature in order to suppress bacterial growth as much as possible, for example, at 10 ° C. or less. It is desirable to process.

  The composition analysis method used in the production method of the present invention can be analyzed by a method known for milk and dairy products, and the method is not particularly limited.

  The desalted milk proposed by the present invention is produced by the production method of the present invention described above.

  There is no restriction | limiting in particular in further processing and processing from the desalinated milk manufactured by this invention. In other words, desalted milk is further concentrated and dried to form powdered milk, desalted milk is diluted into processed milk and milk beverages, and desalted milk and dairy products processed from it are used as raw materials. There are no restrictions on the foods and drinks.

  As described above, any raw fat type, non-fat type, or fat-enriched type can be used as long as the raw material milk is liquid. Then, if a non-fat type is used for raw material milk, demineralized and degreased milk can be produced by the production method of the present invention. By making the raw material milk to be used a full-fat type or a non-fat type, the desalted milk can be further concentrated and dried to produce full-fat milk powder or skim milk powder.

  Hereinafter, the present invention will be described in more detail with reference to experimental examples in which the inventors have completed the present invention and examples of the present invention based on the experimental examples. The present invention is not limited to the above-described embodiment and the following examples, and can be variously modified within the technical scope grasped from the description of the scope of claims. In the following,% is based on weight.

(Test Example 1)
Batch concentration test to confirm the permeation performance of nanofiltration membranes for skim milk.

A nanofiltration membrane (NF3838C / 30-FF) with an average salt removal rate of 97 to 99% with a diameter of 4 inches and a membrane area of 7.4 m ² at about 1300 L / h with skim milk from a supply tank of 3 t capacity The membrane was concentrated to 10 ° C. or lower until the concentration of skim milk was about doubled while discharging only the permeate into the recovery tank. The operating pressure was set to be equal pressure conditions at three levels of 1.2 MPa, 1.4 MPa, and 1.6 MPa, and the concentrated solution was sampled. Refractive sugar content (%), total solid content (%), sodium The content (mg%) and potassium content (mg%) were measured. The measurement results are shown in Table 1.

From the measurement results of Table 1, when membrane concentration with a nanofiltration membrane is performed under an isobaric condition at an operating pressure of 1.6 MPa or less, the relationship between total solid content and refractive sugar content is considered to be as follows: It was.
Total solid content (%) = 0.9338 × refractive sugar content (%) − 0.8478

In addition, the relationship between the average value of the desalting rate of sodium and potassium and the total solid content of the desalted and concentrated milk after concentration was considered as shown in the following formula from the results of Table 1.
Average value of desalting rate of Na and K (%) = 42.3 × Ln (% of total solids) −94.8

  Therefore, in order to obtain a demineralized and defatted concentrated milk having an average value of the desalting rate of sodium and potassium from the dehydrated milk having a total solid content of 9.38%, the total solid content of the demineralized and defatted concentrated milk is obtained from the above formula. It was found necessary to concentrate to 23.9% with a nanofiltration membrane.

  In addition, it is concentrated with a nanofiltration membrane from skimmed milk with a total solid content of 9.38% to a desalted and defatted concentrated milk with a total solid content of 16.02%, and then diluted to a total solid content of 9.38%. It was found that the average value of the demineralization rate of sodium and potassium could be 40% of desalted and defatted concentrated milk by making the salt defatted milk and membrane concentration again to a total solid content of 16.02%.

(Test Example 2)
A wide range of combinations of permeation flux and concentration concentration was set for each membrane concentration condition (permeation flux and concentration concentration), and a continuous operation test was conducted to identify a condition range in which continuous operation for 12 hours was possible.

Nonfat milk is discharged from a 3t-capacity storage tank at a predetermined flow rate with a high-pressure pump, and a nanofiltration membrane (NF3838C / 30) with an average salt removal rate of 97 to 99% with a diameter of 4 inches and a membrane area of 7.4 m ² is used. -FF spiral membrane (manufactured by Dow-Filmtec, USA) was performed, and the treatment temperature was 10 ° C or lower.

Table 2 below shows the setting conditions of the conducted continuous operation test and the results of the continuous operation test.

The data in Table 2 is data obtained by running Run 2 for 7 hours, and Run 1 and Runs 3 to 7 other than Run 2 for 12 hours continuously. The measured TS (%) of the concentrated solution after membrane treatment refers to the average value when continuously operated. As for the flow rate, the lower limit value and the upper limit value data in continuous operation are indicated by the flow meter. The permeated liquid refractory sugar content refers to data of a lower limit value and an upper limit value when continuously operated. The permeation flux (kg / m ² / h) is a value obtained by dividing the flow rate of the permeate by the area of the nanofiltration membrane (7.4 m ² ). This is the upper limit data. “Measurement / average” of the permeation flux refers to the average value in continuous operation.

  While supplying non-fat milk and non-fat concentrated milk to a circulation line with a high-pressure pump from a supply tank, adjusting the operation pressure before and after the nanofiltration membrane to keep the permeate flow rate constant so as to keep the permeate flux constant Continuous operation was performed.

  The results of continuous operation are shown in Table 2 above. In any test, the flow rates of skim milk and concentrate were stable for 12 hours. The concentration of concentrated milk was also stable near the target value. In each test, the operation was performed with the permeation flux almost as set. FIG. 1 shows the transition of the refractive sugar content of the concentrated solution that has passed through the nanofiltration membrane in the operation time.

  From FIG. 1, it was revealed that the refractive sugar content of the concentrate during continuous operation is constant.

The change with time of the operating pressure during continuous operation is shown in FIG.

  From FIG. 2, the operating pressure value during the continuous operation is constant except for Run 2, and it is considered that the continuous operation for 12 hours can be stably performed. In Run 4, an increase in the operating pressure was suggested at the end of the operation, suggesting that the nanofiltration membrane was blocked, but compared to Run 2, the starting time of the increase in the operating pressure was later, and it was judged that operation for 12 hours was possible.

  Based on the above results, the availability of continuous operation was plotted by distinguishing with symbols (◯, Δ, ×), and the 12-hour continuous operation possible region was indicated by hatching in FIG.

From FIG. 3, the range of conditions under which each of the concentrated solids of skim milk can be operated continuously for 12 hours is approximately when the permeation flux is F [kg / m ² / h] and the concentrated solids TS [%]. Within the range shown by the following formula.
Permeation flux F <22.3-TS
(However, F <10.1 and TS <18.9)

As a processing facility for producing desalted and defatted concentrated milk from skimmed milk, a first nanofiltration membrane treatment facility of a three-circulation path system having a total area of 1800 m ² of nanofiltration membrane, and the downstream process thereof is defatted. Equipment for proportionally mixing filtered water obtained by reverse osmosis membrane treatment of the permeate obtained by nanofiltration filtration of milk, and further, in the downstream process, a three-circulation route system with a total area of nanofiltration membrane of 1800 m ² A continuous processing apparatus having a second nanofiltration membrane processing facility was used.

  Desalination rate (salt content in sodium equivalent of manufactured desalted processed milk / salt content in sodium equivalent of skim milk × 100) = 40%, skim milk (solid content 9.4%) Was passed through the apparatus at 20 t / h. The average flow rate of the permeated liquid in the first and second nanofiltration membrane treatment facilities was 8.3 t / h. The desalination rate at the time of leaving the second nanofiltration membrane treatment apparatus remained around 40%, and the desalination rate did not change for more than 12 hours.

(Test Example 3)
Batch concentration test to confirm the permeation performance of nanofiltration membranes for whole milk.

A nanofiltration membrane (NF3838C / 30-) with an average salt removal rate of 97 to 99% with a diameter of 4 inches and a membrane area of 7.4 m ² at about 1300 L / h from a 3 t capacity supply tank with a high-pressure pump. FF spiral membrane, manufactured by US Dow-Filmtec), and after the discharge, the membrane was concentrated at 10 ° C. or lower until the concentration of skim milk was about doubled while discharging only the permeate to the recovery tank. . The operating pressure was set to be equal pressure conditions at three levels of 1.2 MPa, 1.4 MPa, and 1.6 MPa, and the concentrated solution was sampled. Refractive sugar content (%), total solid content (%), sodium The content (mg%) and potassium content (mg%) were measured. The measurement results are shown in Table 3.

From the measurement results in Table 3, when membrane concentration was performed with a nanofiltration membrane under an isobaric condition at an operating pressure of 1.6 MPa or less, the relationship between total solid content and refractive sugar content is considered to be as follows: It was.
Total solid content (%) = 1.15 × refractive sugar content (%) − 1.09

In addition, the relationship between the average value of the desalting rate of sodium and potassium and the total solid content of the desalted and concentrated milk after concentration was considered as shown in the following formula from the results of Table 1.
Average value of desalting rate of Na and K (%) = 50.5 × Ln (% of total solids) −131

  Therefore, in order to obtain a demineralized defatted concentrated milk having an average sodium and potassium demineralization rate of 40% from raw milk having a total solid content of 12.81%, the total solid content of the demineralized defatted concentrated milk is calculated from the above formula. It was found that it was necessary to concentrate with a nanofiltration membrane to 29.6%.

  Concentrate with a nanofiltration membrane from raw milk with a total solid content of 12.81% to desalted and concentrated milk with a total solid content of 25.6%, and then dilute to a total solid content of 12.81%. It was also found that the average value of the desalting rate of sodium and potassium could be 50% of desalted whole fat concentrated milk by making the fat milk and concentrating the membrane again to a total solid content of 25.6%.

(Test Example 4)
A wide range of combinations of permeation flux and concentration concentration for each membrane concentration condition (permeation flux and concentration concentration) was conducted, and a continuous operation test was conducted to identify a condition range in which continuous operation for 12 hours was possible. .

Nonfat milk is discharged from a 3t-capacity storage tank at a predetermined flow rate with a high-pressure pump, and a nanofiltration membrane (NF3838C / 30) with an average salt removal rate of 97 to 99% with a diameter of 4 inches and a membrane area of 7.4 m ² is used. -FF spiral membrane (manufactured by Dow-Filmtec, USA) was performed, and the treatment temperature was 10 ° C or lower.

Table 4 below shows the setting conditions of the continuous operation test and the results of the continuous operation test.

The data in Table 4 is data obtained by running Run 2 for 5 hours, Run 3 for 7 hours, Run 4 for 8 hours, Run 7 for 9 hours, and other Run 1 and Run 5 to 6, and Run 8 to 9 for 12 hours continuously. The measured TS (%) of the concentrated solution after membrane treatment refers to the average value when continuously operated. As for the flow rate, the lower limit value and the upper limit value data in continuous operation are indicated by the flow meter. The permeated liquid refractory sugar content refers to data of a lower limit value and an upper limit value when continuously operated. The permeation flux is a value obtained by dividing the area of the nanofiltration membrane (7.4 m ² ) from the flow rate of the permeate, and the actual measurement values are data of the lower limit value and the upper limit value when continuously operated, respectively. “Measurement / average” of the permeation flux refers to the average value in continuous operation.

  While supplying non-fat milk and non-fat concentrated milk to a circulation line with a high-pressure pump from a supply tank, adjusting the operation pressure before and after the nanofiltration membrane to keep the permeate flow rate constant so as to keep the permeate flux constant Continuous operation was performed.

  The results of continuous operation are shown in Table 4 above. In any test, the flow rate of skim milk and permeate was stable throughout the continuous operation. The concentration of concentrated milk was also stable near the target value. In each test, operation was performed with a permeation flux as set. FIG. 4 shows the transition of the refractive sugar content of the concentrated solution concentrated in the membrane during the operation time.

  FIG. 4 reveals that the refractive sugar content of the concentrate during continuous operation is constant and the composition of the concentrate is also constant.

  FIG. 5 shows the change over time in the operating pressure during continuous operation. From FIG. 5, the operating pressures of Runs 1, 5, 6, 8, and 9 were stable, and continuous operation for 12 hours was possible, but Runs 2, 3, 4, and 7 were nanofiltration membranes during operation. An increase in operating pressure was observed suggesting a blockage of the water, and continuous operation for 12 hours was considered impossible.

  Based on the result of continuous operation, whether or not continuous operation is possible is plotted by distinguishing with symbols (◯, ×), and the region where continuous operation is possible for 12 hours is shown by hatching in FIG.

From FIG. 6, the range of conditions under which each solid content of raw milk can be continuously operated for 12 hours is approximately the following when the permeation flux is F [kg / m ² / h] and the concentrated solid content is TS [%]. It will be within the range indicated by the formula.
Permeation flux F <22-0.8TS
(However, F <9.2 and TS <25.9)

As processing equipment for producing desalted concentrated milk from raw milk, the first nanofiltration membrane processing equipment of the 3 circulation path system with a total area of 1800 m ² of nanofiltration membrane, and the skim milk in the downstream process A facility for proportionally mixing filtered water obtained by subjecting the permeate obtained by nanofiltration filtration to reverse osmosis membrane treatment, and further downstream of the facility, a three-circulation path system with a total area of 1800 m ² of nanofiltration membrane A continuous processing apparatus having two nanofiltration membrane processing facilities was used.

  Desalination rate (salt content in sodium equivalent of manufactured desalted processed milk ÷ salt content in sodium equivalent of skim milk × 100) = 40%, raw milk (solid content 13.0%) The liquid was passed through this apparatus at 20 t / h. The average flow rate of the permeated liquid in the first and second nanofiltration membrane treatment facilities was 8.3 t / h. The desalination rate at the time of leaving the second nanofiltration membrane treatment apparatus remained around 40%, and the desalination rate did not change for more than 12 hours.

As a processing facility for producing desalted and concentrated milk from raw milk, it has a nanofiltration membrane processing facility with a total circulation area of 648 m ^{2 and} a liquid storage facility in the downstream process. The device was used.

  Desalination rate (salt content of sodium in desalted processed milk ÷ salt content in terms of sodium in raw milk x 100) = 50%, with raw milk (12.8% solids) The liquid was passed through the apparatus at 14 t / h, and the average flow rate of the permeated liquid in the first nanofiltration membrane treatment facility was 4.7 t / h. The concentrated liquid after storage was passed at 7.2 t / h, and the average flow rate of the permeated liquid in the second nanofiltration membrane treatment facility was 1.8 t / h. Furthermore, the permeate obtained by nanofiltration filtration of raw milk into the concentrated solution after storage is mixed with filtered water having a composition equivalent to that of water by reverse osmosis membrane treatment, to a solid content of 12.8% Diluted. Furthermore, diluted desalted milk (solid content: 12.8%) was passed at 14 t / h, and the average flow rate of the permeated liquid in the third nanofiltration membrane treatment facility was 4.7 t / h. It was. The concentrated liquid after storage was passed at 7.2 t / h, and the average flow rate of the permeated liquid in the fourth nanofiltration membrane treatment facility was 1.8 t / h. The desalination rate after leaving the fourth nanofiltration membrane treatment apparatus was around 50%, and the desalination rate did not change for more than 12 hours.

  In a predetermined range of nanofiltration membrane area and permeation flow rate, raw milk is concentrated by desalting in a nanofiltration (NF) membrane, then diluted, and further subjected to nanofiltration (NF). ) By desalting the membrane, it is possible to stably produce desalted milk having a constant desalting rate (for example, a decrease of 40% or more in terms of sodium) continuously for a long time (12 hours or more). I found.

  By adopting the method for producing desalted processed milk of the present invention, it is possible not only to desalinate raw milk, but also to produce desalted processed milk as designed as needed. The risk of complicated processes due to the desalting state in which salt is desalted again after salt treatment is reduced, and efficient desalted concentrated milk can be produced.

Claims (17)

After the first membrane concentration treatment is performed on the raw material milk using the nanofiltration membrane, the raw material milk after the first membrane concentration is diluted, and again using the nanofiltration membrane By performing the second membrane concentration treatment, the sodium-equivalent salt content after the second membrane concentration treatment is lower than the sodium-equivalent salt content in the raw milk, A desalinized milk production method for continuously producing a desalination rate at a predetermined value for 12 hours or more ,
Permeation flux in the first membrane concentration treatment and the second membrane concentration treatment: F (kg / m ² / h), solid content concentration of the raw milk and before the second membrane concentration Solid content concentration: between TS (wt%)
F <22-0.8TS
(However, F <9.2 and TS <25.8)
A method for producing desalted milk, wherein the relationship is established . The raw material milk is any of animal milk that has not undergone a reduction step, processed milk produced by reducing a dairy product that is a processed product of the animal milk, and plant-derived milk. The manufacturing method of desalinized milk of description. The method for producing desalted milk according to claim 1 or 2, wherein the raw milk is a whole fat type . The method for producing desalted milk according to claim 1 or 2, wherein the raw milk is defatted . Permeation flux in the first membrane concentration treatment and the second membrane concentration treatment: F (kg / m ² / h), solid content concentration of the raw milk and before the second membrane concentration Solid content concentration: between TS (wt%)
F <22.3-TS
(However, F <10.1 and TS <18.9)
The method for producing desalted milk according to claim 4, wherein the relationship is established . After the first membrane concentration treatment is performed on the raw material milk using the nanofiltration membrane, the raw material milk after the first membrane concentration is diluted, and again using the nanofiltration membrane By performing the membrane concentration treatment for the second time, the desalinized milk for continuously producing desalted milk having a salt content reduced by 40% or more in terms of sodium as compared with the raw material milk for 12 hours or more. A manufacturing method comprising:
Permeation flux in the first membrane concentration treatment and the second membrane concentration treatment: F (kg / m ² / h), solid content concentration of the raw milk and before the second membrane concentration Solid content concentration: between TS (wt%)
F <22-0.8TS
(However, F <9.2 and TS <25.8)
A method for producing desalted milk, wherein the relationship is established . The raw milk is claim 6, wherein the animal milk that has not undergone the reduction step, processed milk made by reducing the dairy is a processed product of the animal milk to be either milk of vegetable origin manufacturing method of desalting milk serial placement. The method for producing desalted milk according to claim 6 or 7, wherein the raw milk is a whole fat type . The method for producing desalted milk according to claim 6 or 7, wherein the raw milk is defatted . Permeation flux in the first membrane concentration treatment and the second membrane concentration treatment: F (kg / m ² / h), solid content concentration of the raw milk and before the second membrane concentration Solid content concentration: between TS (wt%)
F <22.3-TS
(However, F <10.1 and TS <18.9)
The method for producing desalted milk according to claim 9, wherein the relationship is established . In the desalination concentration step in the first membrane concentration treatment and the second membrane concentration treatment, the permeation flux: F (kg / m ² / H) is performed at a constant value, and the desalting concentration step is performed, and continuous operation is performed so that the operating pressure does not increase with the operating time during the desalting concentration step. The method for producing desalted milk according to claim 10. 12. The dewatering according to claim 11, wherein the operating pressure is kept constant during the desalting and concentration step, or the operating pressure is controlled to be within a predetermined range during the desalting and concentration step. A method for producing salt-treated milk. The desalinized milk produced by the desalinized milk production method according to any one of claims 4, 5, 9, and 10 is a desalted and skimmed milk. Method. Method for producing any one desalination process to remove water from the desalination process milk desalted and concentrated milk produced by the manufacturing method of the milk according to claims 1-12. Method of making a claim 13 to remove moisture from the desalination degreased milk produced by the manufacturing method of desalination degreased milk desalting skim concentrated milk according. A method for producing desalted powdered milk by removing water from the desalted milk produced by the method for producing desalted milk according to claim 1, and pulverizing it . A method for producing demineralized skim milk powder by removing moisture from the desalted and degreased milk produced by the method for producing demineralized and skimmed milk according to claim 13 .

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