JPH09182575A - Adsorbent, production of the same and treatment of fruit juice - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an adsorbent capable of removing the bitterness of a fruit juice selectively and at a high efficiency by the suspension polymerization of an aromatic vinyl monomeric compound, etc., in the presence of an inert substance generating a fine structure, and then bringing the produced polymer beads into contact with a lewis acid catalyst. SOLUTION: This adsorbent having >=1200m<2> /g specific surface area based on dry weight thereof, >=0.52ml/ml pore volume based on wet volume thereof and >=75m<2> /ml specific surface area in pores having >=50Å radius thereof, is obtained by the suspension polymerization of a monomer mixture containing an aromatic vinyl monomeric compound as a major component, consisting of divinylbenzene having 81% purity containing ethylvinylbenzene in the presence of an inert substance (e.g.; toluene) generating a fine structure with the addition of a dispersing agent (e.g.; polyvinyl alcohol) and a radial polymerization initiator (e.g.; dibenzoyl peroxide) in a desalted water under heating, and then bringing the obtained porous cross-linked polymer beads into contact with a lewis acid catalyst [e.g.; anhydrous ferric (III) chloride] in the pressure of an inert medium (e.g.; 1,2-dichloroethane).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel adsorbent, a method for producing the same, and a method for removing bitterness from fruit juice using the adsorbent.

[0002]

2. Description of the Related Art Conventionally, the quality of fruit juice, especially citrus fruit juice, varies depending on its plant variety, production area, cropping pattern, picking time, storage period method, juice extraction time, etc. It was difficult to provide a flavor that was stabilized by the treatment. Therefore, as one of the methods for stabilizing the quality of citrus juice, selective removal of the bitterness component from the juice has been carried out. As one of the methods, only the bitterness component is removed by contact with an adsorbent. A method of adsorbing and separating is known. As such a bitter ingredient, naringin, which is a typical flavonoid compound, can be mentioned.
In addition, limonin, which is a terpenoid compound peculiar to citrus fruits, is also known as a bitterness component, but its content is very small, and removal of naringin is the purpose of bitterness removal. This compound has a molecular weight of about 500, and in order to selectively and efficiently remove it using an adsorbent, it is necessary to precisely design and synthesize the hydrophobicity, that is, the chemical structure and pore structure of the adsorbent. is there.

As an example of bitterness removal by an adsorbent, for example,
Journal of the Japan Food Industry Society 1979 Vol. 26, No. 1, pp. 1-5
Adsorbent consisting of styrene-divinylbenzene copolymer
Although the method used is described, the exemplified adsorbents are
It is not designed and synthesized to remove bitterness components,
Surface area is about 700m^Two/ G (per g of adsorbent),
Its processing capacity was small and unsatisfactory.
Japanese Patent Laid-Open No. 60-153780 discloses styrene-divinylbenzene.
A method for removing bitter components using a zen copolymer has been shown.
However, the specific surface area of the adsorbent exemplified in this case is 5
00-700m ^Two/ G (per g of adsorbent). Also,
In Japanese Patent Publication No. 2-503516, a similar polymer is further back mounted.
After the bridge treatment, it was hydrophilized by introducing ion-exchange groups.
An example using a resin is disclosed.
In addition to the complex and multi-step manufacturing method, further ion exchange
Since it has a base, the resin is acidified before and after use to remove bitterness components.
Or it needs to be treated in advance with a chemical such as alkali
However, there are practical problems due to the complexity of the handling process.
Was.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an adsorbent which is easy to manufacture and has excellent bitterness component removing performance. That is, to provide an adsorbent that is suitable for selectively removing the bitterness component of fruit juice with high efficiency and that has a pore structure having a high treatment capacity and that does not contain an ionic functional group and is easy to handle. Is an issue. The present inventors have a hydrophobic chemical structure for the adsorbent to adsorb the bitterness component hydrophobically, and have a pore volume that allows the bitterness component to easily diffuse inside the adsorbent, and further efficiently adsorbs the bitterness component. The present invention could be completed by having a large specific surface area for

[0005]

In order to solve the above-mentioned problems, the present invention comprises, in claim 1, a porous crosslinked polymer obtained by polymerizing an aromatic vinyl monomer compound as a main component. Specific surface area per unit is 1200 m ² / g
(Adsorbent) Above, the pore volume per water wet volume is 0.52
The present invention provides an adsorbent characterized by having a specific surface area of 75 m ² / ml (adsorbent) or more in pores having a radius of 50 ml / ml or more and an adsorbent of 50 Å or more. In Claim 2, the aromatic vinyl monomer compound is divinylbenzene or a mixture of divinylbenzene and ethylvinylbenzene, and the adsorbent according to Claim 1 is provided.

The present invention also provides a porous crosslinked product obtained by suspension-polymerizing a monomer mixture containing an aromatic vinyl monomer compound as a main component in the presence of an inactive substance for expressing a fine structure. The method for producing an adsorbent according to claim 1 or 2, wherein the polymer beads are contacted with a Lewis acid catalyst in the presence of an inert medium. Furthermore, the present invention,
A method for treating fruit juice, which comprises contacting with the adsorbent according to claim 1 or 2.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
In the present invention, the porous cross-linked polymer that constitutes the adsorbent is one obtained by polymerizing an aromatic vinyl monomer compound as a main component. For the porous cross-linked polymer, various known production methods have been disclosed. For example, the porosity of the ion exchange resin described in "Chelate Resin / Ion Exchange Resin" (published by Kodansha in 1976) by Nobu Hojo edited by Hojo Nobu. It can be produced according to the production method of the mother material.

In the present invention, the adsorbent has a specific surface area per dry weight of 1200 m ² / g (adsorption) or more, a pore volume per water wet volume of 0.52 ml / ml (adsorbent) or more, and a radius of 50 Å or more. Has a specific surface area of 75
It is an essential constituent requirement that it is at least m ² / ml (adsorbent). Preferably, the specific surface area per dry weight of the adsorbent is 1200 to 3000 m ² / g (adsorbent), and the pore volume per wet volume of water is 0.52 to 1.0 ml / ml.
(Adsorbent), and the specific surface area in the pores with a radius of 50 Å or more is 75 to 150 m ² / ml (Adsorbent). If it is out of this range, bitterness cannot be selectively and efficiently removed. Or, it becomes difficult to produce such an adsorbent.

The value of the specific surface area per dry weight of the adsorbent (m ² / g dry / adsorbent) was measured by the BET method, and the pore volume per water wet volume of the adsorbent and The value of the specific surface area in the pores with a radius of 50 Å or more is the cumulative pore volume value (ml / g dry adsorbent) and the specific surface area value (m ² / g dry adsorbed) obtained by the BJH (nitrogen adsorption) method, respectively. Agent), the bulk density of the adsorbent in water (g
It is a value obtained by multiplying by (dry / adsorbent / ml water wet / adsorbent).

The aromatic vinyl monomer compound in the present invention is composed of an aromatic monovinyl monomer compound and / or an aromatic polyvinyl monomer compound. In particular, the content ratio of the aromatic polyvinyl monomer compound in the aromatic vinyl monomer compound is preferably in the range of 55 to 100% by weight.

As the aromatic monovinyl monomer compound,
Examples thereof include styrene, vinyltoluene, ethylvinylbenzene, vinylbenzyl chloride and the like. Examples of the aromatic polyvinyl monomer compound include divinylbenzene, trivinylbenzene, divinylnaphthalene and the like. You may use these 1 type or in mixture of 2 or more types. Particularly, as an aromatic vinyl monomer compound, divinylbenzene 100-
A mixture of 55% by weight and 0-45% by weight of ethylvinylbenzene is preferred. In addition, if necessary, a small amount of other copolymerizable vinyl monomer compounds such as aliphatic vinyl monomer compounds may be used in combination with these aromatic vinyl monomer compounds.

In the production method of the present invention, examples of the inactive substance which expresses the fine structure include various compounds which are soluble in the aromatic vinyl monomer compound or the monomer mixture and are substantially insoluble in water. To be Specific examples of these inert substances include aliphatic hydrocarbon compounds such as heptane and octane, aromatic compounds such as benzene, toluene and xylene, halogenated hydrocarbon compounds such as dichloroethane and chlorobenzene, and linear compounds such as polystyrene. The polymer compounds may be used alone or in combination of two or more.
Of these, toluene is particularly preferable as the inert substance. In the present invention, the proportion of the inactive substance used is 30 to 300 parts by weight, preferably 75 to 250 parts by weight, based on 100 parts by weight of the mixture of all vinyl monomer compounds used.

The vinyl monomer compound is prepared by adding a small amount of a polymerization initiator in the presence of the above-mentioned inactive substance and conducting a polymerization reaction.
It becomes a porous cross-linked polymer. As the polymerization initiator, an organic peroxide such as benzoyl peroxide or lauroyl peroxide or an organic azo compound such as azobisisobutyronitrile is used in an amount of 0.01 to 10 per 100 parts by weight of the vinyl monomer compound. It is preferable to use it in a ratio of parts by weight. The polymerization reaction can be carried out according to a known suspension polymerization method,
The resulting product is washed to give porous crosslinked polymer beads. The obtained polymer beads retain the ability to be used as the adsorbent of the present invention as it is, but after the post-treatment by the method for producing an adsorbent of the present invention described later, an adsorbent having improved bitterness removing performance is obtained. Obtainable.

In the method for producing an adsorbent according to the present invention, a monomer mixture containing an aromatic vinyl monomer compound as a main component is suspension-polymerized in the presence of an inactive substance capable of expressing a fine structure to obtain an adsorbent. The porous cross-linked polymer beads thus obtained are brought into contact with a Lewis acid catalyst in the presence of an inert medium to provide a method for producing an adsorbent having specific physical properties. It should be noted that the general catalytic crosslinking reaction of the polymer beads with the Lewis acid catalyst is a known method as described in JP-A No. 4-18436.

The inert medium used in the production method of the present invention may be one that wets the polymer beads and is inert to the Lewis acid. Specifically, it is a halogenated hydrocarbon such as dichloroethane or dichloropropane. Compounds. These inert media should be used in an amount of 1 to 10 g per 1 g of polymer beads. The conditions for contacting with the Lewis acid catalyst are preferably in the range of 50 to 100 ° C. for 1 to 10 hours. After the contact, the catalyst is inactivated and washing treatment is carried out to produce the target adsorbent.

In the production method of the present invention, the specific surface area is 1200 m ² by appropriately selecting the above production conditions.
/ G (dry resin / adsorbent) or more, pore volume 0.52 m
l / ml (water-wetting resin / adsorbent) or more and radius 50Å
It is possible to produce an adsorbent having a specific surface area of 75 m ² / ml (water-wetting resin / adsorbent) or more contributed by the pores. The obtained adsorbent is usually 50 to 2000 μm.
Often used with a particle size of 300-1000μ
Those having a particle size of m are preferred. The adsorbent having the physical properties defined by the present invention is useful for adsorptive separation of various organic compounds in a liquid, and is extremely effective for removing bitterness components in citrus juice, in particular.

The adsorbent according to the present invention can be used in the step of removing the bitterness of fruit juice in a water wet state. That is, the treatment can be carried out by a batch method in which an adsorbent is placed in a container containing fruit juice and brought into contact with it, or a continuous flow method in which the adsorbent is filled in a tower-type contacting device and the fruit juice is passed through. The adsorbent that has been used and deteriorated can be regenerated by bringing it into contact with hot water, hydrous alcohol or the like to desorb and remove components to be adsorbed, and can be reused for fruit juice treatment.

As the fruit juice from which the bitterness can be removed by the adsorbent treatment of the present invention, citrus fruits such as summer mandarin orange,
Tangerine, grapefruit, orange, fruit juice such as lemon, which is preferably used for those containing naringin, limonin, etc. as a bitter ingredient, and not only juice juice squeezed from these fruits, but also filtration and concentration. , Diluted, heated, stored under cooling, mixed with other fruit juices, or processed by adding agents such as sweeteners, cooling agents, acidulants, nutrients and dispersants.

[0019]

EXAMPLES Hereinafter, the method of the present invention will be described in more detail by showing representative examples and comparative examples.

Example 1 Purity 81 containing ethylvinylbenzene as an impurity
% Divinylbenzene (213 g) was mixed with toluene (372 g) and 75% pure dibenzoyl peroxide (2.9 g), and warm demineralized water containing 2.9 g of polybiyl alcohol 205
It was added to 0 ml and stirred to suspend. The temperature was raised with stirring, and a polymerization reaction was carried out at 80 ° C. for 8 hours. The obtained polymer beads were washed with water and dried. Dried polymer beads 1
After swelling by adding 00 g to 500 ml of 1,2-dichloroethane and swelling, 10 g of anhydrous iron (III) chloride was added and the temperature was raised, and the mixture was reacted at 80 ° C. for 8 hours. The obtained beads were washed to obtain adsorbent I. When the specific surface area was measured with a Shimadzu Flowsorb 2300 specific surface area meter, it was 1262 m ² /
g (adsorbent). Further, the pore volume of the adsorbent measured by using a Micromeritics ASAP2400 nitrogen adsorption meter and converted per wet volume of water is 0.55 ml / ml.
(Adsorbent), the specific surface area in the pores with a radius of 50 Å or more was 81 m ² / ml (adsorbent). Adsorbent I (50 ml) in a water-wet state was filled in a glass column having an inner diameter of 14 mm and kept at 40 ° C. Naringin (0.
75 g / l), citric acid (10 g / l) and sucrose (1
Demineralized water in which 00 g / l) was dissolved at 40 ° C. in space velocity (S
V) The solution was passed so as to have a flow rate of 20 BV / hr, and the amount of the solution passed until the leaking concentration of naringin at the column outlet reached 10% of the inlet concentration was 74 BV.

Example 2 The amount of divinylbenzene was 195 g and the amount of toluene was 39 g.
An adsorbent II was obtained in the same manner as in Example 1 except that the amount of 1 g and dibenzoyl peroxide was changed to 2.6 g. The specific surface area per dry weight is 1301 m ² / g (adsorbent), and the pore volume per water wet volume is 0.53 ml / m.
The specific surface area of the pores having an adsorbent of 1 (adsorbent) and a radius of 50 Å or more was 82 m ² / ml (adsorbent). When the naringin solution was passed through in the same manner as in Example 1, the flow rate was 77B.
V.

Comparative Example 1 When a commercially available styrene-divinylbenzene-based adsorbent "Diaion" HP20 (manufactured by Mitsubishi Chemical Co., Ltd.) was measured in the same manner as in Example 1, the specific surface area per dry weight was 6
01 m ² / g (adsorbent), pore volume per wet volume of water was 0.44 ml / ml (adsorbent), and specific surface area in pores with a radius of 50 Å or more was 40 m ² / ml (adsorbent). When the Naringin solution was passed, the flow rate was 43 BV.
Met.

Comparative Example 2 The amount of divinylbenzene was 234 g and the amount of toluene was 35 g.
An adsorbent III was obtained in the same manner as in Example 1 except that 1 g and the amount of dibenzoyl peroxide were 3.1 g. The specific surface area per dry weight of this adsorbent is 1225 m ² / g
(Adsorbent), pore volume per wet volume of water is 0.50 m
The specific surface area of the pores having a radius of 50 Å or more was 77 m ² / ml (adsorbent). Example 1
When the naringin solution was passed through in the same manner as above, the passing amount was 69 BV.

Comparative Example 3 An adsorbent IV was obtained in the same manner as in Comparative Example 2 except that 12 g of polystyrene was added to the mixture of divinylbenzene, toluene and dibenzoyl peroxide. The specific surface area per dry weight of this adsorbent was 1209 m ² / g (adsorbent), the pore volume per wet volume of water was 0.55 ml / ml (adsorbent), and the specific surface area of pores with a radius of 50 Å or more was 54 m.
^{It was 2} / ml (adsorbent). When the naringin solution was passed through in the same manner as in Example 1, the flow rate was 69 BV.

The results of the above Examples and Comparative Examples are summarized in Table 1. From these results, the adsorbent has a specific surface area per dry weight of 1200 m ² / g (adsorbent) or more, a pore volume per water wet volume of 0.52 ml / ml (adsorbent) or more,
And a specific surface area in the radial 50Å or more pores 75 m ²
It can be seen that the effect of the present invention is not exhibited unless all of the following conditions are satisfied: / ml (adsorbent) or more.

[0026]

[Table 1]

[0027]

INDUSTRIAL APPLICABILITY The present invention provides an adsorbent having a pore structure suitable for selectively and efficiently removing the bitterness component of fruit juice, a method for producing the same, and a method for treating fruit juice.

Claims (5)

[Claims] 1. A porous cross-linked polymer obtained by polymerizing an aromatic vinyl monomer compound as a main component and having a specific surface area per dry weight of 1200 m ² / g (adsorbent) or more,
An adsorbent characterized by having a pore volume per wet volume of water of 0.52 ml / ml (adsorbent) or more, and a specific surface area of pores having a radius of 50 Å or more of 75 m ² / ml (adsorbent) or more. 2. The adsorbent according to claim 1, wherein the aromatic vinyl monomer compound is divinylbenzene or a mixture of divinylbenzene and ethylvinylbenzene. 3. A porous cross-linked polymer bead obtained by suspension polymerization of a monomer mixture containing an aromatic vinyl monomer compound as a main component in the presence of an inert substance for expressing a fine structure. The method for producing an adsorbent according to claim 1 or 2, which comprises contacting with a Lewis acid catalyst in the presence of an inert medium. 4. A method for treating fruit juice, which comprises contacting the fruit juice with the adsorbent according to claim 1. 5. The processing method according to claim 4, wherein the fruit juice is citrus fruit juice.