JPH11290041A - Production of vegetable juice - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently carrying out the regeneration of an anion exchange resin, efficiently removing nitrate ions from a vegetable juice and producing the vegetable juice with a low content of the nitrate ions. SOLUTION: A stock solution (a pressed liquid) in a stock solution tank 6 is introduced from a gas-liquid inlet 28 into the upper part of a denitrating column 1 and passed through a resin bed 2 formed of a Cl-form strong basic anion exchange resin to remove nitrate ions. When the regeneration of the resin 2 is required, wash water is introduced from a gas-liquid introduction device 42 to backwash the resin 2 and feed the ion exchange resin into a regeneration column 3. A warm aqueous solution of sodium hydroxide in a downward stream is then passed from a water supply device 57 through the formed resin bed 56 to remove organic impurities sticking to the resin. An aqueous solution of sodium chloride is subsequently introduced from a tank 5 of the aqueous solution of sodium chloride into the regeneration column 3 and in a downward stream is passed from the water supply device 57 therethough to convert the resin into the Cl form. The regenerated resin is returned to the denitrating column 1 to repeat the denitrating treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing vegetable juice in which nitrate ions are removed from a vegetable juice by ion exchange to produce vegetable juice with a small amount of nitrate ions.

[0002]

2. Description of the Related Art Green vegetables such as spinach often contain a large amount of nitrate ions depending on the type of crop, variety, fertilizing conditions, and the like.
Nitrate ions of up to several thousand mg / l may be detected. It is said that when a large amount of nitrate ion is contained, it is not preferable for health, and the corrosion of a metal container such as tinplate is easily promoted.

As a method for solving such a problem, Japanese Patent Application Laid-Open No. 55-131357 discloses a method for removing nitrate ions from a celery juice by ion exchange using a strongly basic anion exchange resin. I have. Since squeezed liquids such as celery, spinach and kale contain a considerable amount of organic components, the organic components adhere to the anion exchange resin during the denitrification treatment. Organic components adhering to the anion exchange resin are removed to some extent during backwashing and regeneration, but some remain attached to the anion exchange resin, and if used in such a state, the processing performance of the anion exchange resin decreases. I do.

However, the type of anion exchange resin to be used and the appropriate regeneration method thereof have not been sufficiently studied in the vegetable juice production method so far. In a series of manufacturing processes that repeat the nitric acid treatment and resin regeneration cycle,
There is a problem that effective processing is not performed.

[0005]

An object of the present invention is to propose a method for efficiently producing vegetable juice having a low nitrate ion content in order to solve the above problems.

[0006]

The present invention is the following method for producing vegetable juice. (1) Vegetable juice that is subjected to a denitrification-regeneration cycle including a denitrification step of adsorbing nitrate ions by contacting a vegetable juice with an ion exchange resin and a regeneration step of regenerating the ion exchange resin adsorbing nitrate ions. In the production method, as the denitrification-regeneration cycle, a denitrification step of adsorbing nitrate ions by bringing a vegetable juice into contact with a Cl-type strongly basic anion exchange resin, and a strongly basic anion exchange resin adsorbing nitrate ions A vegetable juice production method comprising: performing a denitrification-regeneration cycle comprising a regeneration step of contacting an aqueous solution of sodium chloride with an aqueous solution of sodium hydroxide and then contacting the aqueous solution with an aqueous solution of sodium chloride for regeneration. (2) Vegetable juice that is subjected to a denitrification-regeneration cycle including a denitrification step of adsorbing nitrate ions by contacting a vegetable juice with an ion exchange resin and a regeneration step of regenerating the ion exchange resin adsorbing nitrate ions. In the production method, as the denitrification-regeneration cycle, a denitrification step of adsorbing nitrate ions by bringing a vegetable juice into contact with a Cl-type strongly basic anion exchange resin, and a strongly basic anion exchange resin adsorbing nitrate ions Is brought into contact with an aqueous solution of sodium hydroxide and then brought into contact with an aqueous solution of sodium chloride for regeneration.
A denitrification-regeneration cycle comprising a regeneration step; a denitration step of adsorbing nitrate ions by contacting a vegetable squeezed liquid with a Cl-type strongly basic anion exchange resin; and a strong basicity adsorbing nitrate ions. Vegetable juice production characterized by combining a second denitrification-regeneration cycle comprising a second regeneration step of regenerating the anion exchange resin by contacting only an aqueous solution of sodium chloride without contacting the aqueous solution of sodium hydroxide. Method.

[0007] The kind of vegetables used in the method of the present invention is not limited as long as they contain nitrate ions. Specific examples of vegetables include spinach, kale, rape, celery, and the like. The method for obtaining the vegetable juice is also not particularly limited, and can be obtained using a crusher or a press.

The squeezed liquid thus obtained can be directly subjected to a denitrification treatment for removing nitrate ions, but solids such as fibers and other impurities are removed by pretreatment such as filtration and centrifugation. Preferably, the juice is subjected to a denitrification treatment. The concentration of the squeezed liquid to be subjected to the denitrification treatment is arbitrary, but it is 2 to 50 ° as a dissolved solid concentration (Brix degree).
It is preferred to use a juice of Bx, preferably 5-20 ° Bx. In order to adjust the Brix degree to such a range, for example, a vacuum evaporation concentration method of evaporating water under reduced pressure,
It can be performed by a method such as a method of adding water after concentration. The concentration of nitrate ions contained in such a juice is usually 1000 to 6000 mg / l (at 10 ° B
x).

In the method of the present invention, the above-mentioned squeezed liquid is brought into contact with a Cl-type strongly basic anion exchange resin to adsorb and remove nitrate ions. The OH type anion exchange resin is not preferred because the pH of the vegetable juice after denitrification becomes high. Further, since the weakly basic anion exchange resin does not have a neutral salt decomposability, nitrate ions in the form of nitrate cannot be removed.

As the strongly basic anion exchange resin, a tetraalkylammonium salt type I resin having a high basicity is preferred because it is chemically stable, has little organic contamination, and has little odor. Trialkyl alkanol ammonium salt type II resins are not preferred because the resins are liable to be degraded by hydrolysis and may have an unpleasant odor depending on the type of vegetables.

As the strongly basic anion exchange resin, any of a gel type and a porous type can be used, but a porous type is preferred because it absorbs organic impurities. The gel type is not preferable because it is more difficult to wash than the porous type and shortens the use period.

Such a strong basic anion exchange resin is passed through an aqueous sodium hydroxide solution according to the regeneration step described below to carry out washing and conversion to the OH form, and further, is passed through an aqueous sodium chloride solution to remove Cl After shaping, hot water (for example, 7
(0-75 ° C.) and the like to sterilize, and then provide to the denitrification step.

By bringing vegetable juice into contact with such a Cl-type strong basic anion exchange resin,

[Image Omitted] The ion exchange reaction of R—Cl ⁻ + NO ₃ ⁻ → R—NO ₃ ⁻ + Cl ⁻ (1) (wherein R represents a base resin, the same applies hereinafter) proceeds, and The nitrate ions in the squeezed liquid are exchanged and adsorbed on the anion exchange resin to obtain vegetable juice from which the nitrate ions have been removed.

[0014] The contacting method is not particularly limited, and it can be carried out in a batch system. However, it is preferable to pass the squeezed liquid through a column filled with an anion exchange resin. In this case, the liquid may be passed in a downward flow, or may be passed in an upward flow. In order to obtain a nitrate ion removal rate of 90% or more (when the Brix degree is 10 ° Bx), the liquid passing speed is set to SV = 0.5 to 4 h ⁻¹ , preferably SV = ¹ to 2 h ⁻¹ . Is desirable.

When the denitrification step is continued in this way,
Since the ion exchange capacity of the anion exchange resin decreases due to the adsorption of nitrate ions, the process proceeds to the regeneration step. At the time when the denitrification step is completed, the recovery rate of vegetable juice can be increased by extruding the squeezed liquid from the resin layer with pressurized air.

After the squeezed liquid is extruded in this manner, water is added so as to be 100 to 200 mm higher than the resin surface.
It is preferable to extract the squeezed liquid adhering to the resin by stirring, and to completely recover the liquid remaining on the surface and pores of the resin particles. This washing and collecting operation can be performed a plurality of times.

In the regeneration, the squeezed liquid is extruded from the resin layer, replaced with water (eg, pure water), back-washed to remove the suspension adhered to the resin, and then subjected to chemical injection to ion-exchange the resin. Restores ability. Recovery of ion exchange capacity is possible by contact with aqueous sodium chloride solution, but in order to remove organic impurities attached to the resin, contact with aqueous sodium hydroxide solution prior to contact with aqueous sodium chloride solution It is necessary to do.

The contact with the aqueous sodium hydroxide solution can be carried out every time the regeneration treatment is carried out, or can be omitted at the frequency described later. In the former case, a denitrification-regeneration cycle (first regeneration step) comprising the above-mentioned denitrification step and regeneration treatment, that is, a regeneration step (first regeneration step) of contacting with an aqueous sodium hydroxide solution and then regenerating by contacting with an aqueous sodium chloride solution. Denitrification-regeneration cycle). In the latter case, a second denitrification-regeneration cycle comprising this first denitrification-regeneration cycle, and a second regeneration step of contacting only the aqueous solution of sodium chloride without contacting with the aqueous solution of sodium hydroxide without the above-mentioned denitrification step. This is done by combining the cycles.

The first regeneration step is carried out by contacting the strongly basic anion exchange resin with an aqueous solution of sodium hydroxide and then with an aqueous solution of sodium chloride. The first regeneration step of contacting with such an aqueous solution of sodium hydroxide includes:
A first regeneration step using an aqueous solution of sodium hydroxide and an aqueous solution of sodium chloride, and a second regeneration step using an aqueous solution of sodium chloride alone, without performing each time in each regeneration step of the cycle of the denitrification step and the regeneration step. Is preferably performed in combination. Regeneration using an aqueous solution of sodium hydroxide is desirably performed at a rate of 1 to 10 times, preferably 5 to 8 times. The ratio of using the aqueous sodium hydroxide solution can be selected according to the amount of the organic component adhering to the strong basic anion exchange resin. Increase the number of times.

The contact between the strongly basic anion exchange resin and the aqueous sodium hydroxide solution is carried out at a concentration of 2 to 6% by weight, preferably 2 to 6% by weight.
-4% by weight, temperature 35-60 ° C, preferably 50-55.
It is desirable that an aqueous solution of sodium hydroxide at a temperature of 0 ° C. is passed through at a flow rate of SV = 2 to 6 h ⁻¹ , preferably SV = 2 to 4 h ⁻¹ and brought into contact therewith. The liquid can be passed in a downward flow or in an upward flow. The amount (regeneration level) of the aqueous sodium hydroxide solution is preferably 50 to 200 g NaOH / l-resin, and more preferably 100 to 150 g NaOH / l-resin.

By contacting with an aqueous solution of sodium hydroxide, organic impurities in the squeezed liquid adhering to the strongly basic anion exchange resin can be removed, thereby recovering the ability to adsorb nitrate ions and organic impurities. be able to. Also

By the ion exchange reaction of R—NO ₃ ⁻ + NaOH → R—OH ⁻ + NaNO ₃ (2), nitrate ions are eliminated and the resin is converted to the OH form.

The contact with the aqueous solution of sodium hydroxide is carried out following the contact with the aqueous solution of sodium hydroxide, and washing with water in the middle is preferable because the discharge of organic impurities is promoted. Contact with an aqueous sodium chloride solution may be performed.

The contact between the strongly basic anion exchange resin and the aqueous solution of sodium chloride is carried out at a concentration of 2 to 20% by weight, preferably 5 to 20% by weight.
10 to 10% by weight, temperature normal temperature to 60 ° C, preferably 15 to 3
It is desirable that an aqueous solution of sodium chloride at 0 ° C. is brought into contact with the solution at a flow rate of SV = 2 to 6 h ⁻¹ , preferably SV = 2 to 4 h ⁻¹ . The liquid can be passed in a downward flow or in an upward flow. The regeneration level of sodium chloride is 200-500 g NaCl / l-resin, preferably 3
Desirably, the amount is from 00 to 400 g NaCl / l-resin.

When a sodium chloride aqueous solution is brought into contact with the strongly basic anion exchange resin converted into the OH form,

The strongly basic anion exchange resin is regenerated to Cl form by the ion exchange reaction of R—OH ⁻ + NaCl → R—Cl ⁻ + NaOH (3)

On the other hand, when the contact with the aqueous solution of sodium hydroxide is omitted,

[Image Omitted] R-NO ₃ ⁻ + NaCl → R-Cl ⁻ + NaNO ₃ (4) Regenerated to the Cl form by an ion exchange reaction.

After the contact with the aqueous solution of sodium chloride as described above, washing is performed, and the regeneration step is completed. Thereafter, the vegetable juice is brought into contact with the resin to restart the denitrification treatment, thereby producing vegetable juice.

[0027] Even if the above-mentioned regeneration step is performed, the treatment may be deteriorated due to the growth of microorganisms. Therefore, the sterilization treatment is performed a plurality of times, for example, once every 5 to 10 times of the first regeneration step. It is preferred to do so. Sterilization treatment, before restarting the denitrification treatment, strong basic anion exchange resin at 60 ~ 80 ℃,
It is preferably immersed in hot water at 70 to 80 ° C. for 3 to 8 hours, preferably 3 to 5 hours, and sterilized. In particular, when the production of vegetable juice is temporarily interrupted after the regeneration process, the microorganisms may grow during the period until the process is restarted, and the number of cells in the vegetable juice may increase. Is preferred.

The vegetable juice thus obtained is subjected to post-treatment such as instant sterilization using a plate heater cooler or the like, and then used as a raw material for mixing vegetable juice or the like. In this case, since the amount of nitrate ions is reduced, there is no harm to the human body, and corrosion of a metal container such as a tin can during the storage period is suppressed.

[0029]

The method for producing vegetable juice of the present invention includes a step of regenerating a strongly basic anion exchange resin, which comprises the steps of contacting the resin with an aqueous solution of sodium hydroxide and then with an aqueous solution of sodium chloride. The ion exchange capacity of the strongly basic anion exchange resin can be maintained at a high level, whereby a vegetable juice having a low nitrate ion content can be efficiently produced.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in the drawings. FIG. 1 is a system diagram showing an apparatus for producing vegetable juice according to an embodiment. In FIG. 1, reference numeral 1 denotes a denitrification tower, in which a resin layer 2 is formed by a Cl-type strong basic anion exchange resin. 3 is a regeneration tower, 4 is a sodium hydroxide aqueous solution tank, 5 is a sodium chloride aqueous solution tank, 6 is a stock solution tank, 7 is a blower, 8 is a relay tank, and 9 is a processing solution tank.

To produce vegetable juice using the apparatus of FIG.
In the denitrification process, the valves 11, 12, and 13 are opened, and the valves 15, 16, 17, 18, 19, 20, 21, and 33 are opened.
Is closed, the pump 25 is started to take out the undiluted solution (squeezed liquid) from the undiluted solution tank 6 and remove the solid content by passing through the filter 26. Then, the communication path 27 and the gas-liquid introduction port connected thereto are connected. From 28, it is introduced into the upper part of the denitrification tower 1. The undiluted solution introduced into the denitrification tower 1 is passed through the resin layer 2 formed of the Cl-type strong basic anion exchange resin at the above-mentioned flow rate in a downward flow to remove nitrate ions. In the resin layer 2, the ion exchange reaction of the above formula (1) occurs, and nitrate ions are adsorbed and removed. The processing solution from which the nitrate ions have been removed is introduced into the relay tank 8 through the communication path 29 and is temporarily stored.

[0032] Even after the stock solution tank 6 is emptied, the denitrification step is continued to process the stock solution in the upper part of the tower.
In this case, the valves 12, 13, 15 are opened and the valves 11, 1
6, 17, 18, 19, 20, 21, 31, 32, 33
Is closed, the air pressurized by the blower 7 is passed from the gas-liquid inlet 28 through the air path 35 and the communication path 27 to the denitrification tower 1.
And the stock solution is passed through the resin layer 2 to remove nitrate ions. Next, the valve 21 is opened, the valves 12 and 13 are closed, and pure water or soft water is introduced from the water supply channels 36 and 37 and the water supply port 38 to the upper surface of the resin layer 2 so as to have the height described above. Thereafter, the valve 16 is opened and the valve 15 is closed, and air pressurized by the blower 7 is injected into the air passage 35 and the communication passage 41 from the bottom of the denitrification tower 1 and diffused from the gas-liquid introduction device 42. After stirring, the stock solution adhering to the resin is extracted, and the stock solution remaining on the surface and fine pores of the resin particles is completely recovered from the resin layer 2 and stored in the relay tank 8.
The air introduced for air diffusion is exhausted from an exhaust gas path (not shown).

Next, when the resin needs to be regenerated, the valve 1
With the valves 6 and 21 closed and the valves 17 and 20 opened, washing water is introduced from the gas-liquid introduction device 42 through the water supply path 36 and the communication path 41 to wash the resin. The cleaning waste liquid generated at this time is collected by a liquid collecting device 44 and discharged from a liquid discharging path 45. Thereafter, the valves 17 and 20 are closed, and the valves 19 and 2 are closed.
1 and 52 are opened, and the ion exchange resin is transferred to the regeneration tower 3 together with water through the communication path 43. At this time, surplus water is collected by the liquid collecting device 81 and discharged from the drainage passage 45.

In the regeneration tower 3, the valves 54 and 55 are opened, and the valves 19, 21, 33, 51, 52, 53, 58 and 6
Backwashing is performed in a state where the ports 2 and 66 are closed.
6. Discharged through the communication path 75 and the drainage path 45. Next, the valves 54 and 55 were closed, the resin formed a resin layer 56, and a hot sodium hydroxide aqueous solution was passed through the resin layer 56 from the water supply device 57 in the downward flow under the above conditions, and adhered to the resin. Remove organic impurities. In the resin layer 56, the ion exchange reaction of the formula (2) occurs, and the resin is converted to the OH form.

The hot aqueous sodium hydroxide solution to be supplied to the regeneration tower 3 is opened with the valves 61, 62 and 63 open and the valves 65 and 6.
While the pumps 6 and 67 are closed, the pump 68 is driven to take out the aqueous sodium hydroxide solution from the aqueous sodium hydroxide tank 4, and the aqueous solution and pure water or soft water heated by the heat exchanger 71 are sucked by the ejector 72. The hot sodium hydroxide aqueous solution is supplied from the flow channel 73 to the water supply device 57.

Next, the pump 68 is stopped, and the valves 61 and 6 are stopped.
When the valves 2 and 63 are closed and the valves 31 and 51 are open, the air pressurized by the blower 7 is injected from the gas-liquid inlet 76 through the air path 35 and the communication path 75, and the regenerated waste liquid is pushed out from the resin layer 56. . Next, the valves 52 and 53 are opened and the valve 31 is closed, and pure water or soft water is introduced from the water supply passage 36 and the water supply port 78 for cleaning. The regenerated wastewater and the washing wastewater are collected by a liquid collecting device 81 and discharged from a liquid discharging passage 45, and also discharged from a connected liquid discharging passage 82 through a gas-liquid introducing device 64 at the bottom of the tower. Wash water and pressurized air can also be introduced from the gas-liquid introduction device 64. When the regeneration step using the aqueous sodium hydroxide solution is omitted, these operations can be omitted. However, about one out of ten regeneration steps is performed using the aqueous sodium hydroxide solution.

Next, an aqueous sodium chloride solution is introduced from the aqueous sodium chloride tank 5 into the regeneration tower 3, and the resin is regenerated by flowing the aqueous solution from the water supply device 57 in the downward flow under the above conditions. In the resin layer 56, the ion exchange reaction of the above formula (3) or (4) occurs, and the resin is converted into Cl form. The pump 84 drives the pump 84 to take out the aqueous sodium chloride solution to be supplied to the regeneration tower 3.
When the valves 2, 63 are closed and the valves 51, 65, 66, 67 are open, they are suction-mixed by the ejector 85 and supplied to the water supply device 57 from the channel 73. At that time, the drainage that has passed through the resin layer 56 is discharged from the flow path 82. After the completion of this step, the valve 65 is closed, the pump 84 is stopped, and the regenerated effluent is extruded from the resin layer 56, followed by washing.

When the cycle is repeated, the number of bacteria in the processing solution increases due to the proliferation of bacteria in the resin, and the capability of the in-line sterilizer may become insufficient. Therefore, after the end of the regeneration, heat sterilization of the ion exchange resin is performed. First, the valves 51, 62,
63 is opened, and hot water of 70 to 75 ° C. is passed through the resin layer 56. The temperature of the waste water is measured, and when the temperature reaches 70 ° C. or higher, the valves 51, 62, and 63 are all closed, and left as it is for 3 to 5 hours. Thereafter, washing is performed with room temperature water. These operations can be omitted, but about one out of ten regeneration steps is performed while monitoring the increase in the number of bacteria in the processing solution for each cycle.

The regenerated resin is returned to the denitrification tower 1 from the communication path 86 with the valves 18, 33, 58 opened, and the denitration process is repeated again. At this time, the water is discharged through the gas-liquid introduction device 42 by opening the valve 18. The processing liquid in the relay tank 8 is sent to a cyclone 92 and a filter 93 by a pump 91 to remove solids, and then sterilized by an in-line sterilizer 94. In the in-line sterilizer 94,
The hot water in the hot water tank 95 is circulated through the circulation path 97 by the pump 96 to perform indirect heating and sterilize. The sterilized processing liquid is sent to the processing liquid tank 9 and stored therein. The treatment liquid (vegetable juice) thus obtained is used as a mixed raw material of vegetable juice and the like.

Since such a production method includes a regeneration step using an aqueous solution of sodium hydroxide, it is possible to remove organic impurities attached to the resin which cannot be removed only by backwashing. As a result, the ion exchange capacity of the resin is maintained at a high level, and vegetable juice having a low nitrate ion content can be efficiently produced.

[0041]

EXAMPLES Example 1 1) Denitrification Treatment As vegetable juice, spinach was squeezed, concentrated to 30 to 40 ° Bx by a vacuum evaporation method, and frozen and stored. At the time of denitrification, the spinach juice was thawed, diluted with pure water, and adjusted to 10 ° Bx as a stock solution (liquid to be treated) to produce vegetable juice by the method of FIG.

As the Cl-type strong basic anion exchange resin, A-118 (I-type porous type, manufactured by Kurita Kogyo Co., Ltd.) was used. When using resin for the first time,
After passing a 4% by weight aqueous sodium hydroxide solution, washing with pure water, further sterilizing with hot water of 70 ° C. for 3 hours, and then passing a 10% by weight aqueous sodium chloride solution to form Cl and use did. When used for the second and subsequent denitrification treatments, the regeneration treatment described later was followed. In the denitrification treatment, 1 liter of the above resin was packed in an acrylic column having a diameter of 50 mm, and 2 liter of the stock solution was passed downward at 15 ° C. at a flow rate of SV = 1 h ⁻¹ , and No. ¹ was passed. 2.4 liters of the treatment solution of No. 1 was obtained.
Table 1 shows the results such as the nitrate ion removal rate.

2) Regeneration treatment with sodium chloride aqueous solution The resin was regenerated by pouring a 10% by weight aqueous solution of sodium chloride downward at room temperature at a flow rate of SV = 3 h ^-1 .
The amount of sodium chloride used was 400 g / l-resin.
After washing with water, the stock solution was subjected to denitrification by the method of denitration in 1) above. 2 was obtained. Similarly, the regeneration treatment and the denitrification treatment were repeated. 3-No. 9 was obtained. The results are shown in Tables 1 and 2.

[0044]

[Table 1]

[0045]

[Table 2]

Notes to Tables 1 and 2 * 1 Dissolved solids concentration determined by refractometer

(Equation 1)

From the results shown in Tables 1 and 2, when the resin regeneration with the sodium chloride aqueous solution alone is repeatedly performed, the nitrate ion removal rate gradually decreases. Up to the treatment liquid No. 8, the nitrate ion removal rate was 95% or more, indicating that a high removal rate was obtained.

3) Regeneration treatment with aqueous sodium hydroxide solution After obtaining the treatment liquid No. 9, the resin was regenerated using an aqueous sodium hydroxide solution and an aqueous sodium chloride solution. In the case of an aqueous sodium hydroxide solution, a 2% by weight aqueous sodium hydroxide solution at 40 ° C. was passed in a downward flow at a flow rate of SV = 3 h ⁻¹ . The amount of sodium hydroxide used is 1
00 g / liter-resin. Thereafter, after washing with water, regeneration was performed by passing an aqueous solution of sodium chloride in the same manner as described above. Table 3 shows the reproduction results.

[0049]

[Table 3]

Notes for Table 3

(Equation 2) * 2 Absolute amount of BOD component discharged into the regenerated solution (regenerated drainage amount × regenerated drainage BOD concentration) * 3 Of regenerating the resin from which the treatment solution 8 was obtained

From the results shown in Table 3, when the resin was regenerated using an aqueous solution of sodium hydroxide and an aqueous solution of sodium chloride, the amount of organic matter (BOD) discharged (BOD) was lower than when the regeneration was performed using the aqueous solution of sodium chloride alone. (Removed amount) is large, and the regeneration rate of the exchange group of the resin is high.

Using the resin regenerated with the aqueous sodium hydroxide solution and the aqueous sodium chloride solution as described above, the squeezed liquid of spinach was denitrified by the method of 1). 10 treatment liquids were obtained. The results are shown in Table 2, and it can be seen that the nitric acid removal ability of the ion exchange resin is almost restored to the level of a new product by using two liquids for regeneration.

4) Sterilization Treatment According to the denitration treatment of 1) and the regeneration treatment of 2) and 3), the denitrification treatment and the regeneration treatment were carried out for 20 cycles or more, and then the apparatus was stopped for 3 months. Before resuming the operation, the resin was regenerated with an aqueous sodium chloride solution, and the resin was immersed in hot water at 70 to 80 ° C. for 3 hours to perform sterilization.

Using this sterilized resin, the above 1)
The juice of spinach was subjected to a denitrification treatment according to the above method to obtain a treated liquid. The number of general bacteria and the number of molds and yeasts in this treatment solution were measured as follows. For general bacteria, use a standard agar medium and appropriately dilute the sample to 1 m
It was determined after culturing at 37 ° C. for 48 hours by a plate culture method per 1 liter. With respect to mold and yeast, samples were appropriately diluted using a potato dextrose agar medium, and determined by culturing at 30 ° C. for 72 hours per 1 ml of a plate culture method. Table 4 shows the results. In addition, the processing liquid obtained using the resin which was not subjected to the sterilization treatment was also determined in the same manner as described above and used as a control.
Table 5 shows the results.

[0055]

[Table 4]

[0056]

[Table 5]

From the above results, it can be seen that the use of hot water-sterilized resin makes it possible to obtain vegetable juice with a low bacterial count.

Example 2 Kale squeezed liquid adjusted to 10 ° Bx as in Example 1 was used as a stock solution, and denitrification and regeneration with sodium chloride alone were repeated as in Example 1. , No. 1 to No. 7 was obtained. The results are shown in Tables 6 and 7.

[0059]

[Table 6]

[0060]

[Table 7] Notes on Tables 6 and 7 * 1 See Table 1 * 2 See Table 1

No. After obtaining the treating solution of No. 7, the resin was regenerated in the same manner as in Example 1 using an aqueous solution of sodium hydroxide and an aqueous solution of sodium chloride. Table 8 shows the reproduction results.

[Table 8] * 1 See Table 3 * 2 See Table 3 * 3 No. in Table 7 Result of regenerating the resin from which the treatment solution 6 was obtained

From the results shown in Table 8, when the resin was regenerated using an aqueous solution of sodium hydroxide and an aqueous solution of sodium chloride, the amount of organic substances (BOO) discharged (BOO) was lower than when the regeneration was performed using only the aqueous solution of sodium chloride alone. (Removed amount) is large, and the regeneration rate of the exchange group of the resin is high.

Using the resin regenerated with the aqueous sodium hydroxide solution and the aqueous sodium chloride solution as described above, the kale juice was subjected to a denitrification treatment in the same manner as described above.
No. 8 was obtained. The results are shown in Table 7,
It can be seen that the nitrate ion removal rate has recovered to the same level as the initial stage.

Reference Example 1 Resin A-118 similar to that used in Example 1 was prepared by
18 liter packed in 50mm acrylic column, 10 °
Bx spinach squeezed liquid 34 liter denitrification treatment,
A method for increasing the yield was studied.

After all the residual liquid in the denitrification tower is extruded with air, water is further added up to 200 mm above the resin layer surface, stirred with a blower, and extruded again with air to improve the yield by about 3 to 5%. And 82% to 84%. Similarly, when spinach juice concentrated and adjusted to 12 ° Bx is used, the above-mentioned water extraction is performed twice to make 86 to 9
0% recovery is now possible.

The recovery rate (yield) is based on the amount of the undiluted solution, Bri
It was calculated from the amount of the processing solution with respect to x degrees and the Brix degree. In addition, the Brix degree at the lower limit of recovery was set to 1.5 ° Bx for both the start of the passage and the extrusion of water, and care was taken so that the average Brix degree of the treatment liquid did not become 7 ° Bx or less.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an apparatus for producing vegetable juice according to an embodiment.

[Explanation of symbols]

Reference Signs List 1 denitrification tower 2, 56 resin layer 3 regeneration tower 4 sodium hydroxide aqueous solution tank 5 sodium chloride aqueous solution tank 6 stock solution tank 7 blower 8 relay tank 9 treatment solution tank 11, 12, 13, 15, 16, 17, 18, 19 , 2
0, 21, 31, 3233, 51, 52, 53, 54,
55, 61, 62, 63, 65, 66, 67 valve 25, 68, 84, 91, 96 pump 26, 93 filter 27, 29, 41, 43, 75, 86 communication path 28, 76 gas-liquid inlet 35 air Channels 36 and 37 Water supply channels 38 and 78 Water supply ports 42 and 64 Gas-liquid introduction devices 44 and 81 Liquid collection devices 45 Drainage channels 57 Water supply devices 71 and heat exchangers 72 and 85 Ejectors 73 Flow channels 82 Drainage channels 92 Cyclones 94 Sterilizer 95 Hot water tank 97 Circulation path

 ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Takayuki Moribe 3-4-7 Nishi-Shinjuku, Shinjuku-ku, Tokyo Inside Kurita Industry Co., Ltd. (72) Inventor Takuya Katsumata 3-4-2 Nishishinjuku, Shinjuku-ku, Tokyo No. Kurita Industrial Co., Ltd.

Claims (2)

[Claims] 1. A vegetable which is subjected to a denitrification-regeneration cycle comprising a denitrification step of adsorbing nitrate ions by bringing a vegetable juice into contact with an ion exchange resin and a regeneration step of regenerating the ion exchange resin adsorbing nitrate ions. In the method for producing a juice, the denitrification-regeneration cycle includes: a denitration step in which a vegetable squeezed solution is brought into contact with a Cl-type strong basic anion exchange resin to adsorb nitrate ions; and a strong basic anion adsorbing nitrate ions. A method for producing vegetable juice, comprising performing a denitrification-regeneration cycle comprising a regeneration step of contacting an exchange resin with an aqueous solution of sodium hydroxide and then regenerating by contacting with an aqueous solution of sodium chloride. 2. A vegetable which is subjected to a denitrification-regeneration cycle comprising a denitration step of adsorbing nitrate ions by bringing a vegetable juice into contact with an ion exchange resin and a regeneration step of regenerating the ion exchange resin adsorbing nitrate ions. In the method for producing a juice, the denitrification-regeneration cycle includes: a denitration step in which a vegetable squeezed solution is brought into contact with a Cl-type strong basic anion exchange resin to adsorb nitrate ions; and a strong basic anion adsorbing nitrate ions. A first denitrification-regeneration cycle comprising a first regeneration step in which the exchange resin is brought into contact with an aqueous sodium hydroxide solution and then brought into contact with an aqueous sodium chloride solution, and the vegetable squeezed liquid is subjected to Cl-type strong basic anion exchange A denitrification step of adsorbing nitrate ions by contact with the resin, and sodium hydroxide Second de-nitrate of a second reproduction step of reproducing by contacting an aqueous sodium chloride solution only without contact with an aqueous solution - method for producing vegetable juice and performs combination regeneration cycle.