JP7076058B2 - Colorants containing processed indigo leaves - Google Patents

Description

The present invention generally relates to a composition containing a product derived from indigo leaves and cyclodextrin, a method for producing the same, and the use of the composition as a colorant.

Indigo is a raw material for dyeing indigo cloth products such as goodwill, washcloths, yukata, and furoshiki, and these are closely related to Japanese life and form a part of Japanese culture. The roots of the Samurai Blue, the uniform of the Japan national football team, and the official emblem of the 2020 Tokyo Olympics are also indigo, and the indigo color is a traditional Japanese color.
Indigo is not only used as a raw material for dyeing cloth products, but also as a medicinal plant, applied to the skin for detoxification, antipyretic and anti-inflammatory purposes, or decocted and taken as a beverage or food. In addition, along with the recent boom in natural foods, indigo leaves and fruits themselves are also used as food (Non-Patent Document 1).

The traditional Japanese color, indigo, is derived from the pigment indigo (Indigo, Δ2,2'-bi [1H-indole] -3,3'-zion). As mentioned above, indigo has high utility value as an edible product in anticipation of its original physiological activity, but since the pigment component Indigo itself is a component that is completely insoluble in water, the indigo color of indigo was utilized. It is difficult to develop it as a food coloring agent, and there is no successful example of its development.

Generally, as one of the means for dispersing a water-insoluble substance in water, there is a combined use of cyclodextrin, and it is possible to encapsulate a water-insoluble substance in cyclodextrin and disperse it in water. For another purpose, for example, in Patent Document 1, carotenoid pigments, comfrey pigments, Benibana pigments, cutinashi pigments, monascolor, and annatto color, which are natural pigments for food additives, are included with β-cyclodextrin. A method is described, the purpose of which is to improve the thermal stability and photostability of natural dyes, and other techniques that combine a dye component and cyclodextrin are known, but all of them are cyclodextrins. The purpose of use is different, and no extract from indigo or dextrin is described as a dye molecule (Patent Document 2, Patent Document 3, Patent Document 4, Non-Patent Document 2).

In addition, edible indigo has already been cultivated and processed products and extracts have been commercialized, but the color of the processed products and extracts does not exhibit the vivid indigo color peculiar to indigo dyeing, which is the original color of plants. It has a greenish color, and the difficulty of drawing a bright indigo color from this edible indigo is also considered to be one of the reasons why indigo was not developed as a natural coloring agent, especially as a coloring agent for foods.

Tokukousho 60-45229 Gazette Japanese Patent Application Laid-Open No. 2006-197804 Japanese Patent Application Laid-Open No. 2004-259783 WO2008 / 062861 Gazette

Tokushima Prefectural Herbal Encyclopedia (Tokushima Shimbun / 1984) Analytica Chimica Acta 389 (1999) 291-298

Kuchinashi pigments (red, blue, yellow) are widely used as natural colorants for food additives, but bright indigo natural colorants derived from indigo, which is a traditional Japanese color, do not yet exist. Indigo itself has high expectations as a health food, and in order to make indigo a natural colorant for foods that makes use of its indigo color, it was necessary to make the water-insoluble indigo, which is the pigment component, water-soluble. In addition, in order to commercialize it as a coloring agent, it was necessary to devise something to divert the original bright indigo color of indigo as an edible coloring agent.

As a result of diligent studies for the purpose of producing a water-soluble natural colorant for food additives using natural indigo, the present inventor devised a treatment with an enzyme or the like for the extract of indigo leaves to produce a natural colorant. We have found that it is possible to produce a composition containing an indigo leaf processed product that has a bright indigo color by concentrating the indigo component to a high concentration and containing cyclodextrin to ensure water solubility, and completed the present invention.

Therefore, the present invention includes the following aspects.
<Composition containing processed indigo leaf product and cyclodextrin>
[1]
A composition containing a processed indigo leaf product containing indigo derived from indigo leaves at a concentration of 70% or more, and cyclodextrin.
[2]
The composition according to [1], wherein the amount of cyclodextrin is 1 to 10 equivalents with respect to indigo.
[3]
The composition according to [1] or [2], which is in a crushed state.
[4]
The composition according to any one of [1] to [3], which is dispersed in an aqueous solvent.
[5]
The composition according to [4], wherein some and / or all of the indigo in the indigo leaf processed product contains an inclusion complex that is inclusion with cyclodextrin.
[6]
The composition according to any one of [1] to [5], which is a colorant.
[7]
The composition according to [6], which is a food coloring agent.
<Manufacturing method of composition containing processed indigo leaf product and cyclodextrin>
[8]
1) Indigo leaves are boiled in an aqueous solvent to obtain an extract containing indican, treated with β-glucosidase, the indigo-containing precipitate is collected by filtration, and the obtained indigo-containing precipitate is crushed to be derived from indigo leaves. A processed indigo leaf product containing 70% or more of indigo is prepared, and then 2) the obtained processed indigo leaf product is mixed with cyclodextrin and pulverized.
[1] A method for producing the composition according to the above.

The indigo-colored natural colorant created by the processed indigo leaf product of the present invention has a natural and vivid color tone when colored, and is safe for the body. By using it in products such as processed foods, sweets, and beverages, it is expected that the range of development of value-added food-related products will be greatly expanded. In recent years, research on the effects of eating indigo on beauty and health has become active, and the effects of improving cholesterol levels and reducing visceral fat have been proved, and the effects can be expected in that respect.
Furthermore, the indigo natural colorant can be applied not only to foods and beverages, but also to various daily necessities and furniture that make use of traditional Japanese colors.

It is a schematic diagram which shows the process of producing the composition containing the indigo leaf processed product and cyclodextrin, and the colorant. FIGS. 2-1 and 2-2 and FIG. 2-3 show that the composition of the present invention containing the processed indigo leaf product and cyclodextrin is a water-soluble colorant. FIG. 2-1 is a photograph showing the state of dissolution immediately after mixing. It is a photograph showing the state of dissolution of the composition of the present invention containing a processed indigo leaf product and cyclodextrin after being allowed to stand for one day. It is a photograph which shows the state of the precipitation of the bottom of a test tube after standing for one day. It is a graph which measured the solution which dissolved indigo leaf processed product in chloroform by the absorption spectrum. It is a graph which measured the coloring liquid immediately after mixing by the absorption spectrum about the composition of this invention containing the green leaf processed product and 1 equivalent, 2 equivalents and 3 equivalents of α-cyclodextrin. It is a graph which measured the coloring liquid immediately after mixing by the absorption spectrum about the composition of this invention containing the green leaf processed product and 1 equivalent, 2 equivalents and 3 equivalents β-cyclodextrin. It is a graph which measured the coloring liquid immediately after mixing by the absorption spectrum about the composition of this invention containing the green leaf processed product and 1 equivalent, 2 equivalents and 3 equivalents of γ-cyclodextrin.

Hereinafter, the present invention will be described in more detail with reference to FIG. 1 as appropriate.
The present invention relates to, as one embodiment, a processed indigo leaf product containing indigo derived from indigo leaves at a concentration of 70% or more, and a composition containing cyclodextrin. The composition of the present invention corresponds to [E] in FIG.

The "indigo leaf" in the present invention is usually a small upper powder of the Polygonaceae family, and is a plant "Tateai" (Polygonum tinctrium Lour.) It means the leaves of the family plant "Mercurialis leiocarpa Siebold". Preferably, it is a leaf of "Buckwheat" (Polygonum tinctrium Loure.).

The indigo leaf processed product contained at a concentration of 70% or more of indigo disperses in water and is finally substantially included in cyclodextrin. From this point of view, the higher the concentration of indigo in the product, the more preferable it is, preferably 80% or more, and further preferably 90% or more. Ordinary dried indigo leaves contain about 0.2% indigo, about 10% precipitated indigo, and about 10% squid.

In the present invention, cyclodextrin is a cyclic oligosaccharide in which both ends of an oligosaccharide in which glucose is linked are bonded to form a ring, and utilizes an inclusion action of incorporating various molecules into the internal cavity thereof. Cyclodextrin includes "α-cyclodextrin" in which 6 glucoses are bound to form a ring, "β-cyclodextrin" in which 7 are bound, and "γ-cyclodextrin" in which 8 are bound. be. In the present invention, any of α-, β-, and γ-cyclodextrin can be used, and α-cyclodextrin is preferable.

In another aspect, the present invention provides a composition in a ground state containing a processed indigo leaf product containing 70% or more of indigo derived from indigo leaves and cyclodextrin. The composition of the present invention is finally dispersed and dissolved in an aqueous solvent, and is used as a food coloring agent. In order for the processed indigo leaf product to disperse well in an aqueous solvent, it is necessary to form an inclusion complex with cyclodextrin. Therefore, at least the composition of the present invention is preferably in a pulverized state.
In this embodiment, the present invention, in another aspect, in the composition of the present invention dispersed in an aqueous solvent, and in the composition of the present invention dispersed in an aqueous solvent, a part of indigo in a green leaf processed product and / Or provide a composition of the invention containing an inclusion complex which is all inclusions in cyclodextrin.

The "water solvent" used to form the inclusion complex of the present invention has sterility suitable for eating and drinking such as drinking water and distilled water because the composition of the present invention is used as a food coloring agent. Means the water that is there.

The "processed indigo leaf product" of the present invention means a product obtained by subjecting a natural indigo leaf to a predetermined process, and the outline of the production method thereof is as shown in FIG.
Indigo leaves are boiled in an aqueous solvent at 100 ° C. to 110 ° C. for 10 to 20 minutes to obtain an extract [A] containing indican, treated with β-glucosidase, and the indigo-containing precipitate is collected by filtration. The indigo-containing precipitate [C or D] obtained is crushed to produce a processed indigo leaf product containing indigo derived from indigo at a concentration of 70% or more.

As the "indigo leaf" used in the processed product of the present invention, since the present invention also aims at a food coloring agent, it is preferable to use indigo cultivated without using pesticides or pesticides. In the production method of the present invention, when "sukumo" obtained through the fermentation step is used as a starting material, it is a mere detour route in the present invention.

The composition of the present invention
1) Indigo leaves were boiled in an aqueous solvent at 100 ° C. to 110 ° C. for 10 to 20 minutes to obtain an extract containing indican, treated with β-glucosidase, and the indigo-containing precipitate was collected by filtration. The indigo-containing precipitate is crushed to produce an indigo leaf processed product containing indigo derived from indigo at a concentration of 70% or more, and then 2) the obtained indigo processed product is mixed with cyclodextrin and pulverized.
Manufactured by process. The obtained mixture is preferably pulverized by a ball mill, an electric millstone mill, or the like.

The "aqueous solvent" used in the production method of the present invention includes ordinary water such as tap water and groundwater, as well as water containing a certain amount of alcohol. The alcohol content is preferably 20% to 75%.
By boiling the indigo leaf at 100 ° C. to 110 ° C. for 10 to 20 minutes, the bacteria and enzymes adhering to the indigo leaf are sterilized and inactivated, and the soluble component [A] containing indican is extracted. When preparing the extract [A] containing indican, a predetermined amount of indigo leaves are packed in a heat-resistant net or the like and boiled, which is convenient for removing the indigo leaves and recovering the extract. Alternatively, an extract containing indican can be prepared by putting a predetermined amount of indigo leaves into a container containing an aqueous solvent, heating the container, and filtering the boiled liquid.

Then, the obtained indican-containing extract is enzymatically treated with β-glucosidase to convert indican into indigo [B].
The amount of β-glucosidase used is preferably 10 to 30 times the amount of indican. The enzyme treatment is usually carried out at a temperature of 40 to 60 ° C., preferably about 50 ° C. for about 1 to 2 hours. Enzymatic treatment usually involves oxygen bubbling to increase the dissolved oxygen concentration, with a pressure of preferably 0.01 to 1.0 MPa, more preferably 0.1 MPa. Next, the obtained indigo-containing precipitate was collected by filtration using filter paper or the like [C], and if necessary, washed with 50% ethanol water or alcohol such as ethanol in order to remove flavonoids contained in the indigo leaves. Purify and then dry [D]. Usually, the concentration of indigo after alcohol purification is around 90%. Next, the obtained indigo was subjected to 1 to 10 equivalents, preferably 1 to 5 equivalents, more preferably 1 to 3 equivalents, and more preferably 2 equivalents of α-, β- and / or γ. -The composition [E] of the present invention is obtained by mixing with cyclodextrin and even more preferably 2 equivalents of α-cyclodextrin and pulverizing. Grinding is performed by a ball mill, ultrasonic waves, a grinder, a flour mill, or the like.

The composition [E] is stored as it is or refrigerated. In the present invention, the composition [E] before being made into a solution can also be referred to as a water-soluble colorant [F]. When the water-soluble colorant [F] of the present invention is used as a colorant, the colorant [F] is used in an amount of 0.001 to 0.1 vol% depending on the purpose as the concentration of the processed indigo leaf product. Dissolves in an aqueous solvent. However, the concentration of this processed indigo leaf product is not important as long as the indigo color appears.

The colorant [F] of the present invention can be widely used for food and industrial purposes. For industrial use, it is used for eyeglasses, furniture, clothing, paints, building materials, etc. For foods, it is used as a food coloring agent for Japanese and Western confectionery, candy, ice cream, cooking, tea, buckwheat, drinking water, alcohol such as Japanese sake and liqueur, and processed foods. Food colorants are pigments used for the purpose of coloring foods during manufacturing and processing. The color of food has the effect of increasing appetite and enriching eating habits.

Hereinafter, the present invention will be described in detail by way of examples, but it should be noted that these do not limit the scope of the present invention and are merely examples. In the examples, FIG. 1 is cited as appropriate.

Example 1
Production of indigo water-soluble colorant 1-1: Production of indican aqueous solution After enclosing 1.5 kg of indigo leaves harvested in Taraya-cho, Tokushima City in a heat-resistant net, soak in 6.25 L of boiling water and extract with hot water for 20 minutes. conduct. Then, the indigo leaves were removed and the filtrate was recovered to obtain a high-concentration indican extract. The amount of indican was analyzed by high performance liquid chromatography and found to be 8.1 g.

1-2: Production of processed indigo leaf product Add 234 g of β-glucosidase to the indican extract [A] obtained in 1-1, and perform enzyme treatment for 2 hours while performing oxygen bubbling (0.1 MPa) at about 50 ° C. .. The treated precipitate was recovered using production filter paper No. 26 (manufactured by Advantech Toyo), and the recovered precipitate was used with 50% ethanol water and ethanol to remove flavonoids contained in the indigo leaves. The remaining precipitate was dried to obtain a processed indigo leaf product having a purity of 82% and 3.3 g.

1-3: Production of a composition containing a processed indigo leaf product and cyclodextrin The processed indigo leaf product obtained in 1-2 was subjected to ultrasonic treatment in water to make particles finer. The processed indigo leaf product that had been refined by ultrasonic waves was freeze-dried, and the processed indigo leaf product that had been refined was recovered. The finely divided indigo leaf processed product and 1 equivalent, 2 equivalents, and 3 equivalents of α, β, and γ-cyclodextrin, respectively, were mixed using a mortar to obtain nine compositions.

Example 2
Quality Evaluation of Water-Soluble Colorant Using 9 compositions and water containing 1 equivalent, 2 equivalents and 3 equivalents of α, β, γ-cyclodextrin prepared in Example 1, processed indigo leaf product [Example 1]. 1-2] was prepared in an amount containing a concentration of 0.005 vol%. Immediately after mixing, and then allowed to stand for one day, each precipitate was visually confirmed. Since the amount of the precipitate after standing for one day was very small, it was judged that each composition of Example 1 was a water-soluble colorant. The photographs showing the obtained results are shown in FIGS. 2-1 and 2-2 and 2-3.
As can be seen from FIG. 2-3, 2 equivalents of α-cyclodextrin had the least amount of precipitate.

In addition, the colored liquid immediately after mixing was measured by an absorption spectrum, and this was compared with the absorption spectrum of a processed indigo leaf product dissolved in chloroform as a control. The absorption spectra of the nine compositions prepared in Example 1 showed similar or higher values as compared with the control. From this as well, it was determined that each composition of Example 1 was a water-soluble colorant. The obtained results are shown in FIGS. 3-1 to 3-4. In addition, since the 2 equivalents of α-cyclodextrin show the highest absorption spectrum, it is also shown that the 2 equivalents of α-cyclodextrin are cyclodextrins suitable for solubilizing indigo leaf processed products. Was done.

Considering the potential of Awa Ai, we created an industry using indigo from an unprecedented unique perspective, and developed Japan Blue's natural colorant, which is used as the color of the official emblem of the 2020 Tokyo Olympics. Commercialize. Due to the great demand for Japan Blue's natural colorants, the area of Aihata in Tokushima Prefecture is expected to increase. In addition, great industrial promotion can be expected for the secondary industry that manufactures and sells foods using Japan Blue's natural coloring agents. The creation of the next industrialization is expected.

Claims (7)

A composition containing a processed indigo leaf product containing indigo derived from indigo leaves at a concentration of 70% or more, and cyclodextrin , wherein the amount of cyclodextrin is 1 to 5 equivalents with respect to indigo . The composition according to claim 1 , which is in a crushed state. The composition according to claim 1 or 2 , which is dispersed in an aqueous solvent. The composition according to claim 3 , wherein a part and / or all of the indigo in the green leaf processed product contains an inclusion complex which is included with cyclodextrin. The composition according to any one of claims 1 to 4 , which is a colorant. The composition according to claim 5 , which is a food coloring agent. 1) Indigo leaves are boiled in an aqueous solvent to obtain an extract containing indican, treated with β-glucosidase, the indigo-containing precipitate is collected by filtration, and the obtained indigo-containing precipitate is crushed to be derived from indigo leaves. A processed indigo leaf product containing 70% or more of indigo is prepared, and then 2) the obtained processed indigo leaf product is mixed with cyclodextrin and pulverized.
A method for producing a processed indigo leaf product containing indigo derived from indigo leaves at a concentration of 70% or more, and a composition containing cyclodextrin .

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