JP2020150850A - Method for removing bitterness of citrus fruit product - Google Patents

Abstract

To provide a simple and inexpensive removal method of limonin for removing bitterness of citrus such as Citrus natsudaidai and Citrus grandis, and stably supplying fruit juice to a large number of people, which even a small-scale citrus producer can use.SOLUTION: A method for removing a bitterness component of citrus fruit juice in which a CDP immobilized cellulose sponge composite material is used as a selective adsorbent of limonin, and which includes bringing the material into contact with citrus fruit juice or the like. It is preferable that the contact of a cyclodextrin polymer complex (CDP complex) and citrus fruit juice be performed by shaking or agitating a mixture of the CDP complex and the citrus fruit juice, and shaking or agitation be performed for 15 minutes or more. It is preferable that a contact amount of the CDP complex be 10 g or more for 100 g of the citrus fruit juice.SELECTED DRAWING: Figure 1

Description

The present invention relates to a field for removing a bitter component contained in citrus juice.

Citrus fruits such as grapefruit, sweet summer, Banpeiyu, and Kawachi Bankan contain flavonoids such as naringin as bitter components and health functional components such as antioxidant activity, obesity prevention, and hypertension prevention. On the other hand, limonoids as triterpene derivatives such as limonin are also contained as bitter components and functional components such as antitumor and antibacterial properties. Naringin presents a refreshing bitterness, while limonin is an intense bitterness with a squid feeling that remains in the mouth, causing deterioration in the quality of fruit products. (Non-Patent Document 1)

The bitterness of limonin significantly reduces the value of the citrus fruits it contains. Eliminating this unpleasant bitterness is an important issue for the citrus industry. Already in 1984, Shaw et al. Used a water-insoluble β-cyclodextrin polymer (hereinafter abbreviated as CDP) to reduce the concentration of the bitter component limonin in grapefruit juice to 4 ppm, which is below the threshold, while reducing sugar content, acidity, citric acid, etc. It is reported that the above was maintained without change (Non-Patent Document 2).

However, this CDP preparation method is one in which the epichlorohydrin cross-linking agent is once agglomerated in an alkaline aqueous solution, insolubilized and crushed, and is glassy and brittle, and has a problem in its shape stability. There was a concern that debris that had collapsed during the adsorption operation using the column method or batch method would block the flow of juice and not only block the flow of the column, but would also be mixed into the juice product. Further, due to the instability of the CDP structure, there is a problem in the durability of the CDP after repeated use many times. In addition, there was a problem in separability from insoluble impurities in fruits such as pulp in citrus fruit juice. Therefore, it was not actually used industrially to remove the bitterness of citrus fruits.

On the other hand, a method of directly adding cyclodextrin (hereinafter referred to as "CD") to juice to mask a bitter component such as limonin to reduce bitterness has been attempted (Non-Patent Document 3). Since this method adds a considerable amount of CD alone to the product, not only is the cost high, but the flavor of the beverage is lost and the flavor is reduced.

In addition, a method of using a hydrophobic resin such as polyolefin as a bitter adsorbent (Patent Document 1) is also known, but this method has a problem that the flavor of juice deteriorates because it adsorbs the flavor (non-patent). Patent Document 4). As yet another method, a method by pressurization (Patent Document 2) has been reported, but this method has a problem that a large-scale high-pressure device is required.

On the other hand, a complex with cellulose has been reported as a material using a novel cyclodextrin polymer (Patent Document 3).

Japanese Patent Application Laid-Open No. 5-328915 Japanese Patent Application Laid-Open No. 4-370079 Japanese Patent Application Laid-Open No. 2009-242556

Miyake et al., Journal of Japanese Society of Food Life, 28, 41 (2017) P. E. Shaw, et. al. , J. Agric. Food. Chem. , 32, 832 (1984) Fragrance Journal No. 63, 73 (1983) Shin Hasegawa, Chemistry and Biology, 21 (12), 823 (1984)

Therefore, the present invention removes the bitterness of citrus fruits such as Amanatsu and Banpeiyu, and stably supplies fruit juice to a large number of people. Therefore, simple and inexpensive limonin removal that can be used even by small-scale citrus producers. The purpose is to provide the law.

As a result of repeated studies on a method for removing limonin, the present inventors have used a CDP-immobilized cellulose sponge composite material as a selective adsorbent for limonin and brought it into contact with citrus juice or the like to obtain the above-mentioned prior art. We found that the removal of limonin from citrus fruits could be achieved easily and efficiently while solving the problem.

More specifically, the present invention relates to the following invention:
(1) A method for removing the bitter component of citrus juice, in which the citrus juice is brought into contact with a cyclodextrin polymer complex (hereinafter referred to as "CDP complex") formed by binding a cyclodextrin polymer to a cellulose sponge. How to include.
(2) The method according to (1), wherein the contact between the CDP complex and the citrus juice is carried out by shaking or stirring a mixture of the CDP complex and the citrus juice.
(3) The method according to (2), wherein the shaking or stirring is performed for 15 minutes or more.
(4) The method according to (2) or (3), wherein the amount of the CDP complex at the time of contact treatment between the cyclodextrin polymer complex and citrus juice is 10 w / w% or more.
(5) The method according to (1), wherein the contact of the citrus juice with the CDP complex is carried out by passing through the CDP complex.
(6) The method according to any one of (1) to (4), wherein the cyclodextrin is β-cyclodextrin and / or γ-cyclodextrin.
(7) The method according to any one of (1) to (6), wherein the bitterness component is limonin.

By using the CDP complex, it was possible to produce a new citrus juice product having a refreshing citrus flavor and sweetness without bitterness from citrus fruits such as sweet summer juice and banpeiyu juice. In particular, the method of the present invention does not require a large-scale device unlike other methods, and limonin can be isolated at a high concentration by a simple operation. Therefore, a citrus juice product from which bitterness has been removed easily and inexpensively can be obtained. Can be manufactured. For this reason, it provides a method for removing bitter components that can be used at the production site even by small-scale citrus farmers.

In addition, the CDP complex had sufficient chemical and mechanical strength, and the bitter component was gently dissociated with ethanol in a short period of time so that it could be used repeatedly many times. Therefore, the CDP complex is a material that can withstand continuous use with almost no mechanical stress from the outside, and can be used for producing citrus juice products that are stable and have less bitterness even after repeated use. .. Therefore, it was shown that it is a material with very good cost performance.

Therefore, the present invention removes the bitterness of citrus fruits such as Amanatsu and Banpeiyu while dramatically improving the water insolubilization and continuous mechanical stability of CD and the separation operation from the aquatic environment containing citrus impurities. It is possible to do that.

It is a graph which shows the relationship between the amount of CDP complex and the amount of limonin removed. The vertical axis shows the content (ppm) of limonin contained in the juice after contact with the CDP complex, and the horizontal axis shows the amount of the CDP complex used (w / w%). It has been shown that as the amount of CDP complex used increases, the content of limonin tends to decrease. It is a graph which shows the relationship between the shaking time and the content of the limonin remaining in the fruit juice when the mixture of the CDP complex and the sweet summer juice is subjected to the shaking contact treatment. The vertical axis shows the concentration of limonin remaining in the juice (μg / ml), and the horizontal axis shows the shaking time (minutes). It was shown that the concentration of limonin decreased to less than half after 15 minutes of shaking. It is a graph which shows the result of the removal of limonin in Banpeiyu juice by the CDP complex using each CD of α-CD, β-CD, and γ-CD. STD shows the control group which has not been treated with the CDP complex, and α-CDP, β-CDP and γ-CDP are CDP complexes using the respective CDs of α-CD, β-CD and γ-CD, respectively. The processing group is shown. The vertical axis shows the content of limonin remaining in the juice (μg / g). Although the limonin content was reduced to less than half when any of the CDs was used, the decrease in limonin tended to be larger in β-CD and γ-CD as compared with α-CD.

In one aspect, the present invention relates to a method for removing the bitter component of citrus juice, which comprises contacting the CDP complex with the citrus juice. As used herein, the term "Amanatsu" means the fruits of plants belonging to the genus Citrus, Amanatsu, Trifoliate orange, etc., for example, Amanatsu, Lime, Bergamot, Citron, Lemon, Zabon, Bampeil Buntan. , Grapefruit, Hassaku, Daidai, Natsumikan, Tankan, Iyokan, Hyuga Natsu, Amanatsu (Amanatsu), Yuzu, Sudachi, Kabos, Mikan, Satsuma mandarin, Yatsushiro mikan, Mandarin, Ponkan, Kishu mikan, Shikuwasa, Trifoliate orange, Kinkan , Haxen, obalactone, evodin, and citsaminolide. The citrus juice means a liquid obtained by squeezing citrus juice. The juice does not have to be 100% and is included in the juice of the citrus fruits herein as long as it contains the liquid obtained by squeezing the citrus fruits.

Examples of the "bitterness component" of citrus juice include limonoids, limonin, and nomilin.

As used herein, the cyclodextrin can be any one of α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin, or a mixture of any two or more kinds (two kinds or three kinds). A cyclodextrin polymer is a polymer obtained by cross-linking two or more cyclodextrins with a cross-linking agent such as a polyacid anhydride, and the cross-linking usually occurs in three dimensions. Depending on the degree of cross-linking, CDP has water-soluble and insoluble polymers. For example, water-insoluble CDP can be obtained by synthesizing CD: polyacid anhydride under heating conditions of 1: 3 or more and 100 ° C. or more.

As used herein, the term "cyclodextrin polymer complex" or "CDP complex" means a complex of a cyclodextrin polymer and a cellular sponge having a structure in which a cyclodextrin polymer is bound to a cellulose sponge. The method for producing the CDP complex of the present specification can be carried out by referring to the description of JP-A-2009-242556. The size of the cellulose sponge can be any size as long as the fruit juice can easily penetrate into the interior and can be easily recovered by a mesh having a network structure. For example, the size of the cellulose sponge can be 100 cm ³ or less. , 75 cm ³ or less, 50 cm ³ or less, 27 cm ³ or less, 25 cm ³ or less, 8 cm ³ or less, or 1 cm ³ or less. The size of the cellulose sponge can be 0.1 cm ³ or more, 0.5 cm ³ or more, and 0.8 cm ³ or more. The shape of the cellulose sponge is not particularly limited, but may be a sphere, a cylinder, a triangular prism, a cube, a quadrangular prism, a hexagonal prism, or a shape similar thereto. For example, 0.5 cm square, 0.8 cm square, 1 cm square, 1.3 cm square, or 1.5 cm square or a range between any of these numerical values (eg, 0.5 to 1.5 cm square, 0.8 to 0.8 to It may have a cube of (1.3 cm square, etc.) or a similar shape. In particular, when the bitterness component is removed by passing through a CDP complex column, for example, it is preferable to have a shape suitable for filling the column, and a sphere or a shape having the same inner diameter as the column can be considered. In addition, when the bitterness component is removed by mixing the fruit juice and the CDP complex in the container and shaking or stirring, the size may be sufficiently movable in the container by the stirring or shaking. preferable.

The method of contacting the CDP complex with the citrus juice is not particularly limited, but for example, the bitter component may be removed by flow separation. That is, the bitterness component may be continuously captured and removed by the CD by passing the citrus juice through the column packed with the CDP complex.

Alternatively, the bitter component of citrus juice may be removed by batch separation. For example, the bitter component in the citrus juice may be removed by binding to the CD by shaking or stirring the container containing the mixture of the CDP complex and the citrus juice. In this case, the shaking or stirring time is preferably 15 minutes or more. The speed at the time of shaking or stirring can be 50 rpm or more, 80 rpm or more, 90 rpm or more, or 100 rpm or more. The maximum value of shaking or stirring speed can be 200 rpm, 180 rpm, 150 rpm, 130 rpm, or 100 rpm. Preferably, the shaking or stirring speed is 100 rpm. The amount of CDP complex per 100 g of citrus juice in the mixture can be 10 g or more, 20 g or more, 30 g or more, 40 g or more, or 50 g or more. The amount of CDP complex per 100 g of citrus juice in the mixture can be 100 g or less, 90 g or less, 80 g or less, 70 g or less, 60 g or less, or 50 g or less. Preferably, the amount of CDP complex per 100 g of citrus juice in the mixture is any value between these minimum and maximum values, eg, 10 g or more and 100 g or less.

The citrus juice from which the bitterness component has been removed is easily recovered from the mixture with the CDP complex by filtering using a mesh having a network structure made of a material applicable to foods such as metal or plastic. be able to.

In addition, the CDP complex after use for removing the bitter component of citrus juice separated from the mixture can be regenerated by dissociating the bound bitter component by shaking it in an organic solvent such as ethanol. The shaking time in the dissociation treatment can be 30 minutes to 5 hours, preferably 1 hour or more. After the shaking treatment, the organic solvent is appropriately removed by evaporation or the like to obtain a regenerated CDP complex in which the bitterness component is dissociated. The regenerated CDP complex can be used as a CDP complex in the above-mentioned bitterness removal of citrus juice.

Hereinafter, the present invention will be specifically described with reference to examples of the present invention, but the present invention is not limited thereto. In addition, all references cited herein are incorporated herein by reference.

(Example 1)
Using the CDP complex manufacturing method (Japanese Patent Laid-Open No. 2009-242556) reported by Aomori Prefectural Industrial Technology Center et al., CDP is bound to a cubic Toray cellulose sponge (Toray Fine Chemical Co., Ltd., Japan) of about 1 cm square. It was. Using the obtained CDP complex, simple and inexpensive bitterness removal of citrus fruits containing limonin as a bitter component such as sweet summer juice or Banpeiyu juice was performed. This CDP complex has a structure in which CDP is immobilized inside the cavity of the cellulose sponge by three-dimensionally cross-linking the CD to polymerize it, and further binding and immobilizing it to a cellulose sponge having a continuous cavity diameter.

All of the CDP complex (manufactured by Environmental Engineering Co., Ltd., purchased from Saidin Co., Ltd.) and instruments (2L plastic container, wire mesh for filtration, etc.) were sterilized and sterilized with boiling water. 720 g of commercially available Amanatsu juice was put into a plastic container, and 216 g of β-CDP complex was added. A plastic container containing a mixture of fruit juice and CDP complex was set in a shaker, and the mixture was shaken at 100 rpm for 1 hour. After the shaking was completed, the CDP complex was separated from the mixture with a wire mesh having a grain size of 1 cm or less, and the juice was transferred to a special bottle. It was considered that the CDP cavity and the cellulose sponge in the CDP complex adsorbed essential oil components such as limonene in addition to limonin.

After the bitterness component was removed, the sweet summer juice and the CDP complex could be separated by simply passing them through a stainless steel mesh having a diameter of 20 cm, which has a mesh diameter smaller than 1 cm, for a moment and filtering the juice.

Table 1 shows the results of measuring the limonin concentration before and after the bitterness removal treatment by this method with the sweet summer juices of the two companies. It is said that the threshold value for bitterness of limonin is 6 ppm, and this method was able to reduce the amount of limonin to a level at which almost no bitterness was felt in the sensory test.
For HPLC analysis, Kanto Chemical Mightysil RP-18GP (5 μm), 150 mm × φ4.6 mm, water: acetonitrile 1: 1 was used as the mobile phase, and elution was performed at a flow rate of 0.5 ml / min. The detection wavelength was measured at 210 nm. The limonin standard substance used was manufactured by Fuji Film Wako Co., Ltd.

(Example 2)
In order to find the minimum amount of CDP complex required for the bitterness component of 50 g of fruit juice, the amount of limonin removed was determined by the same method as in Example 1 except that the amount of CDP complex used was various. Measured by HPLC.

The relationship between the amount of CDP complex and the amount of limonin removed is shown in FIG. As a result, it was found that for 100 g of sweet summer juice, the use of 30 g of the CDP complex reduced the amount to 8 ppm, and the use of 45 g of the juice reached 5 ppm, which was below the bitterness threshold of limonin.

(Example 3)
In order to determine the minimum shaking time for limonin removal, the amount of limonin removed was measured by HPLC using the same method as in Example 1 except that the shaking time was various.

The relationship between the CDP complex, the amount of limonin removed, and the amount of limonin removed is shown in FIG. As a result, it was found that the shaking time was reduced to 8 ppm, which was close to the bitterness threshold, within 15 minutes.

(Example 4)
A sensory test was conducted by tasting the taste of Amanatsu new fruit juice from which bitterness was removed using a CDP complex containing each of α-CD, β-CD, and γ-CD.

The results are shown in Table 2. As a result, it was obtained that the fruit juice produced by the β-CDP complex had the best taste. Therefore, it is considered that limonin is best removed by the β-CDP complex.

(Example 5)
The bitterness of Banpeiyu juice was removed using the CDP complex. It was confirmed that the commercially available Banpeiyu juice contains 140 ppm of limonin, and that a sensory test by tasting also causes considerable bitterness (not shown). To this was added 30 w / w% CDP complex and treated in the same manner as in Example 1. When the juice after the treatment was measured by HPLC, limonin was reduced to 50 ppm. A sensory test of the treated juice showed that although some bitterness remained, the taste was significantly improved compared to the untreated juice (not shown). Further, as in Example 4, bitterness was removed using a CDP complex containing each of α-CD, β-CD, and γ-CD. The result is shown in FIG. Banpeiyu juice tends to have a slightly lower limonin content in β-CD and γ-CD than in α-CD, but untreated fruit juice (STD) regardless of which CD is used. It was shown to reduce the limonin content by about 60% as compared to.

(Example 6)
In Example 1, the CDP complex that had been adsorbed was collected in a 500 ml container, immersed in 200 ml of ethanol, and shaken for 1 hour to remove the adsorbate. The ethanol solution was distilled off under reduced pressure with an evaporator to dry the adsorbed components. The adsorbed component obtained was 36 g. Using the recovered CDP complex, limonin in the fruit juice was further removed by the same method as in Example 1. This limonin removal and desorption of the adsorbent from the CDP complex were repeated.

As a result, it was shown that it can sufficiently withstand at least 20 times of repeated use without deteriorating the adsorption performance (not shown).

Claims (8)

A method for removing the bitter component of citrus juice, which comprises contacting the citrus juice with a cyclodextrin polymer complex in which a cyclodextrin polymer is bound to a cellulose sponge. The method according to claim 1, wherein the contact between the cyclodextrin polymer complex and the citrus juice is carried out by shaking or stirring a mixture of the cyclodextrin polymer complex and the citrus juice. .. The method according to claim 2, wherein the shaking or stirring is performed for 15 minutes or more. The method according to claim 2 or 3, wherein the amount of the CDP complex to be contacted with 100 g of the citrus juice is 10 g or more. The method according to any one of claims 2 to 4, wherein the size of the cellulose sponge is 1 cm ³ or more. The method according to claim 1, wherein the contact of the citrus juice with the CDP complex is carried out by passing through the CDP complex. The method according to any one of claims 1 to 6, wherein the cyclodextrin is β-cyclodextrin and / or γ-cyclodextrin. The method according to any one of claims 1 to 7, wherein the bitterness component is limonin.