JP2001348507A - Method for purification of anthocyanin pigment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove odorous component from an anthocyanin pigment solution obtained from red radish and suppress the generation of residual smell. SOLUTION: An anthocyanin pigment is purified by filtering an anthocyanin pigment solution obtained from red radish with an RO membrane or a UF membrane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for purifying an anthocyanin dye, and more particularly, to a method for purifying an anthocyanin dye from an anthocyanin dye solution containing an odor component such as a red radish dye extract. About.

[0002] Natural anthocyanin-based dyes such as red radish dyes are useful substances as food additives, dyes such as color inks, coloring agents for pharmaceuticals and cosmetics, and the like.

[0003] The red radish pigment is a pelargonidin pigment among anthocyanin pigments, exhibits stable properties under acidic conditions, and is particularly useful because it emits clearer red than red pigments from other plants.

[0004]

2. Description of the Related Art Hitherto, a method for purifying an anthocyanin dye using a UF membrane (ultrafiltration membrane) or an RO membrane (reverse osmosis membrane) has been proposed. For example, Japanese Patent Application Laid-Open No. 52-21032
In the publication, an anthocyanin-based pigment extracted from grape is treated by a combination of an ultrafiltration step and a reverse osmosis step. In JP-A-59-223756, anthocyanin-based dyes such as purple corn, red cabbage, berries or grape peel are treated using a cationic or adsorptive resin and an ultrafiltration membrane. However, there is no description or suggestion about removal of sulfides and the like, which are odor components unique to red radish.

[0005] Anthocyanin-based pigments extracted from red radish are more useful than red pigments from other plants as described above, but on the other hand, odors peculiar to radish are transferred to produce scents or return odors. There were problems such as this, and it was not used frequently.

[0006]

An object of the present invention is to remove odor components contained in an anthocyanin-based dye solution obtained from red radish and to suppress returned odor.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to solve the above-mentioned problems. As a result, first, a trace amount of odor component of the aqueous solution of red radish dye was converted into a gas of the red radish extract by a headspace method. Special GC analysis method with concentrated phase components /
Confirmation of odor peak According to GC method / GC-MS method, CH ₃ − such as dimethyl disulfide, dimethyl trisulfide, etc.
(S) Tetra. Represented by n-CH ₃ (where n = 2 to 6)
They have been found to be sulfides such as penta-hexa bodies.

Next, the present inventors use a difference in molecular weight between the red radish dye and the odor component to perform a RO film or UF film treatment to obtain a red radish dye solution with reduced odor. I found that I can do it. Furthermore, it has been found that the above-mentioned membrane treatment can also reduce a low-molecular-weight sulfur-containing component (hereinafter, referred to as an S-containing component), which is considered to be one of the causes of the return odor, and can also prevent the return odor. Reached.

That is, the gist of the present invention is a method for purifying an anthocyanin-based dye, which comprises filtering an anthocyanin-based dye solution obtained from red radish using an RO membrane or a UF membrane.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An aqueous solution of anthocyanin dyes that can be used in the present invention is obtained from red radish containing sulfides as odor components and natural anthocyanin dyes. Specifically, for example, an extract such as red radish and red turnip is mentioned. Among them, red radish is preferred.

An aqueous solution of an anthocyanin pigment is obtained by, for example, cutting the above plant to such an extent that the pigment can be extracted, adding an appropriate amount of water, immersing the mixture, stirring if necessary, extracting the pigment component contained in the plant, and filtering. It can be obtained by: In this case, it is desirable to extract the aqueous solution while maintaining the pH of the aqueous solution on the acidic side. The pH of the extract is usually 7 or less, preferably 4 or less, more preferably in the range of about 1 to 4. As the acid used for adjusting the pH, for example, citric acid, tartaric acid,
Organic acids such as malic acid and acetic acid and inorganic acids such as hydrochloric acid, sulfuric acid and phosphoric acid can be mentioned.

The extract thus obtained contains an anthocyanin-based pigment component and sulfides as odor components.

Next, the aqueous solution containing the odor component and the dye component is treated with an RO film or a UF film to remove the odor component and the low molecular weight S-containing component. As a method of membrane treatment, for example, a dye solution is filtered by a cross flow method, and while continuously extracting a filtrate containing an odor component, water or a weakly acidic aqueous solution corresponding to the filtrate that has escaped into the dye solution is continuously added. A method of adding the solution and performing a filtration treatment until the final withdrawal amount of the filtrate and the addition amount of water or a weakly acidic aqueous solution becomes 1 to 10 times the amount of the dye solution.

As the RO film to be used, a relatively loose RO film having a salt rejection of 10 to 70% is usually used, and specific examples thereof include NTR-7410 manufactured by Nitto Denko and NTR.
R-7430, NTR-7450 and the like. As the UF membrane to be used, usually, a UF membrane having a molecular weight cut off of 6000 or less and a relatively small molecular weight is used. Specific examples thereof include SEP-0013 and SAP-001 manufactured by Asahi Kasei Corporation.
3, SIP-0013 and the like. Examples of the weakly acidic aqueous solution include an aqueous solution of the above-described organic acid or inorganic acid. By this film treatment, a dye solution with reduced odor can be obtained.

The aqueous solution of anthocyanin-based dye used in the present invention is purified by being treated with an RO membrane or a UF membrane as described above, but is preferably subjected to a synthetic adsorption resin treatment before or after the membrane treatment. As a method of the synthetic adsorption resin treatment, for example, a dye solution containing a dye component and an odor component is passed through a synthetic adsorption resin column, and first, both the odor component and the dye component are adsorbed to the resin, and the resin is first broken through. There is a method in which the recovery is started from the passing solution containing the coloring component coming out, and the coloring solution between the passing solution containing the odor component coming out afterwards is collected.

As the synthetic adsorption resin used in the present invention, a non-polar porous adsorption resin having a network molecular structure such as a styrene-divinylben copolymer resin or an acrylic ester copolymer resin is preferable. As specific examples, Diaion HP-20, HP-50, SP-206, SP
-825 (all manufactured by Mitsubishi Chemical Corporation); Amberlite XA
D-2, XAD-4, XAD-7, XAD-8 (or more,
Rohm and Haas).

The liquid may be passed through an aqueous solution containing an odor component and a dye component, followed by an aqueous solvent not containing these components. The pH of the aqueous solvent used for the passage is preferably 4 or less, more preferably about 1 to 4. As the acid used for adjusting the pH, those described above are used.

The passing speed of the liquid is not particularly limited. If the flow rate is high, the throughput per apparatus can be secured. However, there is a limit because turbulence of flowing water or the length of the adsorption zone is increased.
The lower the speed, the better the adsorption, but conversely, the throughput per unit time decreases. Therefore, the liquid passing speed is usually SV =
0.1 to 10 is suitable.

The amount of liquid passed before the breakthrough of the dye component starts is about 3 to 4 times (3 to 4 BV) the bed volume (hereinafter, this may be referred to as "BV"). It may be performed after passing 1 to 10 BV, preferably 2 to 6 BV.

Also, while the dye component is adsorbed on the resin, the passing liquid is transparent, and turns red when the dye component starts to break through. Therefore, the absorbance of the passing liquid is checked to determine the collection starting point. It is preferable to decide. The end point of the collection may be determined by previously confirming the breakthrough point of the odor component with the bed volume as described above, or it can be sufficiently determined even if a person smells the odor. The determination can also be made by analyzing the sulfides in the gas phase sample used. By this resin treatment, a dye solution having almost no odor can be obtained.

By the above-mentioned film treatment, a dye solution having a small odor and a small return odor can be obtained. Further, by combining the film treatment and the resin treatment, it is possible to obtain a dye liquid which is almost odorless and has little return odor. The order of the film treatment and the resin treatment, the number of treatments, and the combination of the film and the resin type are not particularly limited.

The dye solution thus obtained can be made into a concentrated solution by a commonly used method known per se.

[0023]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 1 kg of red radish was cut into a suitable size, 5 liters of a 1% aqueous solution of citric acid was charged in a large extractor, and the mixture was extracted at room temperature for about 8 hours and repeated three times. A red radish dye extract was prepared by separating the extract and collecting the collected liquid by using a heating and decompression concentrator to bring the liquid obtained by evaporating and removing water into a kettle and bringing it into contact with a resin. A part of the solution was filtered through a glass fiber filter paper having a pore size of 1.6 μm, and then subjected to a test described below as a red radish pigment stock solution. The absorbance at 512 nm (A512 value) of the red radish dye stock solution was 290.

500 mL of the red radish dye stock solution was filtered by a cross-flow method using an RO membrane NTR-7430 manufactured by Nitto Denko Corporation, and the filtrate containing the odor component was continuously extracted while the filtrate which had passed through the dye stock solution was matched. Of 0.1% citric acid aqueous solution was continuously added, and filtration treatment was performed until the final amount of filtrate withdrawn and the amount of added citric acid aqueous solution became 1.5 L, and 500 mL of red radish RO membrane treatment liquid was removed. Obtained. The A512 value of the treatment liquid was 265. The treated solution was analyzed for sulfides by headspace GC, and at the same time, the odor was evaluated by a sensory test. The results are shown in Table 1. Further, the treatment liquid is placed in a refrigerator (about 4 ° C).
For one month, and then sulfides were analyzed in headspace GC, and at the same time, the odor was evaluated by a sensory test. The results are shown in Table 2.

Example 2 In the same manner as in Example 1, 500 mL of red radish R
An O membrane treatment solution was obtained, and the treatment solution was passed at a flow rate of SV = 3 through a 20 cm ³ synthetic adsorption resin DIAION HP20 (manufactured by Mitsubishi Chemical Corporation) packed in a glass column having a diameter of 12.5 mmφ. From column 5, the flow through the column was started to be collected, and 410 mL of the resin flow liquid was obtained. The A512 value of the treatment liquid is 26
It was 0. The treated solution was analyzed for sulfides by headspace GC, and at the same time, the odor was evaluated by a sensory test. The results are shown in Table 1. Further, the treated liquid was stored in a refrigerator (about 4 ° C.) for one month, and then sulfides were analyzed in headspace GC, and at the same time, the odor was evaluated by a sensory test. The results are shown in Table 2.

Example 3 600 mL of a red radish dye stock solution was packed in a glass column having a diameter of 12.5 mmφ and passed through a synthetic adsorption resin DIAION HP20 (manufactured by Mitsubishi Chemical Corporation) of 20 cm ³ at a flow rate of SV = 3 to obtain a BV = 3, start collecting the liquid passing through the column,
500 mL of a resin passing liquid was obtained. The dye treatment liquid is subjected to a filtration treatment by a cross-flow method using a UF membrane SEP-0013 manufactured by Asahi Kasei, and while the filtrate is continuously extracted, a 1% aqueous citric acid solution corresponding to the filtrate discharged into the dye treatment liquid is continuously added. , And filtered until the final amount of filtrate withdrawn and the amount of added citric acid aqueous solution become 1.5 L.
0 mL of a red radish UF membrane treatment liquid was obtained. A of the processing solution
The 512 value was 125. The treated solution was analyzed for sulfides by headspace GC, and at the same time, the odor was evaluated by a sensory test. The results are shown in Table 1. Further, the treated liquid was stored in a refrigerator (about 4 ° C.) for one month, and then sulfides were analyzed in headspace GC, and at the same time, the odor was evaluated by a sensory test. The results are shown in Table 2.

Comparative Example 1 600 mL of a red radish dye stock solution was packed in a glass column having a diameter of 12.5 mmφ and passed through a synthetic adsorption resin Diaion HP20 (manufactured by Mitsubishi Chemical Corporation) of 20 cm ³ at a flow rate of SV = 3. = 3, start collecting the liquid passing through the column,
500 mL of a resin passing liquid was obtained. The A512 value of the treatment liquid was 280. The treated solution was analyzed for sulfides by headspace GC, and at the same time, the odor was evaluated by a sensory test. The results are shown in Table 1. Further, the treated liquid was stored in a refrigerator (about 4 ° C.) for one month, and then sulfides were analyzed in headspace GC, and at the same time, the odor was evaluated by a sensory test. The results are shown in Table 2.

[0029]

[Table 1] A512 sulfite (relative value) Sensory evaluation red turmeric dye stock solution 290 1.0 +++++ Example 1 265 0.2 + Example 2 260 0.04- Example 3 125 0.02- Comparative example 280 0.1 + -: No odor + To +++: The more +, the stronger the smell

[0030]

[Table 2] Sulfite Relative value Sensory evaluation red turmeric dye stock solution 1.0 ++++ Example 1 0.3 ++ Example 2 0.2 + Example 3 0.2 + Comparative example 0.7 ++++-: No odor + ~ ++++: + The more the smell, the stronger the smell

[0031]

According to the present invention, an anthocyanin-based dye solution containing a sulfide as an odor component is subjected to RO treatment or UF membrane treatment to obtain a dye solution with reduced odor and reduced return odor. It becomes possible. Further, by performing a purification treatment in which the RO membrane treatment or the UF membrane treatment is combined with the synthetic adsorption resin treatment, the above-described effect is improved.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shuichi Abe 1-1 Kurosaki Castle Stone, Yawatanishi-ku, Kitakyushu City, Fukuoka Prefecture Inside the Kurosaki Office of Mitsubishi Chemical Corporation (72) Inventor Makoto Ishikawa 1st Kurosaki Castle Stone, Yawata-Nishi-ku, Kitakyushu City, Fukuoka Prefecture No.1 Mitsubishi Chemical Corporation Kurosaki Office F-term (reference) 4B018 MA02 MF01

Claims (3)

[Claims] 1. A method for purifying an anthocyanin-based dye, which comprises filtering an anthocyanin-based dye solution obtained from red radish using an RO membrane or a UF membrane. 2. A method for purifying an anthocyanin dye, comprising contacting the filtered anthocyanin dye solution according to claim 1 with a synthetic adsorption resin. 3. The method according to claim 1, wherein an anthocyanin-based dye solution obtained from red radish is brought into contact with the synthetic adsorption resin.
3. A method for purifying an anthocyanin-based dye, which comprises performing filtration as described in 1. above.