阅读说明：本技术 栀子蓝色素及其制造方法 (Gardenia blue pigment and preparation method thereof ) 是由 西川正洋 山下顺也 三浦歌织 藤森贤一 于 2020-04-06 设计创作，主要内容包括：本发明的目的在于提供呈现明亮且泛红减少的鲜明的蓝色色调的栀子蓝色素及其制造方法。通过进行第一工序和第二工序,可以得到呈现明亮且泛红减少的鲜明的蓝色色调的栀子蓝色素,所述第一工序是使选自大豆肽、芝麻肽和大米肽中的至少1种肽与京尼平在溶剂中在不供给包含氧气的气体的条件下反应,所述第二工序是对上述第一工序中得到的反应液在供给包含氧气的气体的条件下进行处理。(The purpose of the present invention is to provide a gardenia blue pigment which exhibits a bright and clear blue hue with reduced redness, and a method for producing the same. A gardenia blue pigment exhibiting bright and sharp blue color tone with reduced reddening can be obtained by performing a first step of reacting at least 1 peptide selected from the group consisting of soybean peptide, sesame peptide and rice peptide with genipin in a solvent without supplying an oxygen-containing gas and a second step of treating the reaction solution obtained in the first step with supplying an oxygen-containing gas.)

1. A gardenia blue pigment having a color value E obtained by diluting it with water^10％ _1cmIn the case of a 0.1 solution, L in the Lab color system^*The value is shown as a of 66 or more^*The values are shown below-24.

2. The gardenia blue pigment according to claim 1, wherein the color value E is obtained by diluting with water^10％ _1cmB in Lab color System in the case of 0.1 solution^*Values are shown above-30.

3. The gardenia blue pigment according to claim 1 or 2, wherein when the operations shown in the following (1) to (3) are further performed, a color difference Δ E between the solution A which has been heat-treated at 90 ℃ for 15 minutes and the solution B which has not been heat-treated is obtained^* _abL of solution A which is 3.5 or less and heated at 90 ℃ for 15 minutes^*Value is shown as 64 or more, a^*Values shown below-14, b^*The value is shown to be above-31,

the operating conditions are as follows:

(1) preparing:

diluting gardenia blue pigment with 0.1M citric acid buffer solution with pH of 2.5 to prepare color value E^10％ _1cm0.1 solution A, and further, gardenia blue pigment was diluted with a 0.1M citric acid buffer solution having a pH of 6.0 to prepare a color value E^10％ _1cmA solution B of 0.1 of the total weight of the polymer,

(2) heating treatment of the solution:

the solution A was subjected to a heat treatment at 90 ℃ for 15 minutes, the solution B was not subjected to a heat treatment,

(3) measurement of color tone:

l in Lab color system was measured for solution A which had been heat-treated at 90 ℃ for 15 minutes and solution B which had not been heat-treated^*Value a^*Value b and^*the value is obtained.

4. The gardenia blue pigment according to any one of claims 1 to 3, wherein the maximum absorption wavelength of the gardenia blue pigment is in a region of 604nm or more.

5. A food or beverage colored with the gardenia blue pigment according to any one of claims 1 to 4.

6. A method for preparing gardenia blue pigment comprises the following steps:

a first step of reacting at least 1 peptide selected from the group consisting of a soybean peptide, a sesame peptide and a rice peptide with genipin in a solvent without supplying a gas containing oxygen; and

and a second step of treating the reaction solution obtained in the first step under a condition that a gas containing oxygen is supplied.

7. The production method according to claim 6, wherein the proportion of peptides having a molecular weight of 2000 or less in the peptides is 45% or more, and the content of free amino acids is less than 20% by mass.

8. The production method according to claim 6 or 7, wherein in the first step, polyphenol is further coexistent in the solvent.

9. The production method according to any one of claims 6 to 8, wherein air is used as the oxygen-containing gas.

Technical Field

The present invention relates to gardenia blue pigment which exhibits a bright and clear blue hue with reduced redness. In addition, the invention relates to a preparation method of the gardenia blue pigment.

Background

Conventionally, as a blue colorant used in foods and the like, food blue No. 1 (disodium 2- (bis {4- [ N-ethyl-N- (3-sulfophenyl methyl) amino ] phenyl } methylonium) benzenesulfonate), spirulina pigment, gardenia blue pigment, and the like have been known. Edible blue No. 1 and spirulina pigments are bright, less reddish, highly yellowish, vivid blue pigments, and have a characteristic of having a vivid blue hue. However, since edible blue No. 1 is a synthetic colorant, there is a tendency to avoid use as consumer's awareness of food safety increases. In addition, spirulina pigments, although natural pigments, are susceptible to fading by heat and are also expensive. On the other hand, gardenia blue pigment is a natural pigment, has stability to heat, overcomes the above disadvantages of edible blue No. 1 and spirulina pigment, and is commonly used in the field of food and the like.

The gardenia blue pigment is produced by allowing β -glucosidase and a primary amino group-containing compound to act on iridoid glycoside obtained from fruit of gardenia jasminoides ellis belonging to family Rubiaceae under aerobic conditions. However, the gardenia blue pigment obtained by such a production method is not sufficient in brightness and is reddish, and therefore is not sufficient in color tone.

Therefore, various techniques have been studied to improve the color tone of gardenia blue pigment.

For example, patent document 1 discloses that a gardenia blue pigment having a bright blue color with reduced reddish to purplish feeling can be obtained by subjecting iridoid glycoside derived from fruits of gardenia belonging to the family rubiaceae to β -glucosidase treatment in the presence of a casein degradation product treated with a proline-specific endoprotease.

Patent documents 2 and 3 disclose that gardenia blue pigment having a bright blue hue can be obtained by performing the following steps: a) a step of treating geniposide with glucosidase to obtain a hydrolysate; b) extracting the hydrolysate obtained in step a) with a solvent to obtain a product containing genipin; c) a step of reacting the product obtained in the step b) with an aqueous solution containing an amino acid and/or a salt thereof to produce gardenia blue pigment.

Patent document 4 discloses that a gardenia blue pigment having a bright blue color tone with reduced red to purple tinges can be obtained by performing the following steps: subjecting iridoid glycoside extracted from fruit of Gardenia jasminoides Ellis of Rubiaceae to beta-glucosidase treatment in the presence of protein decomposition product, and mixing polyphenol with the prepared gardenia blue pigment, or subjecting iridoid glycoside extracted from fruit of Gardenia jasminoides Ellis of Rubiaceae to beta-glucosidase treatment in the presence of protein decomposition product and polyphenol.

Patent document 5 discloses that when gardenia blue pigment is produced by allowing an aglycone of an iridoid glycoside and a taurine-containing substance to coexist under aerobic conditions, a polyphenol compound is added during or after the production, whereby gardenia blue pigment having a bright color tone can be obtained.

However, the techniques of patent documents 1 to 5 still provide reddish gardenia blue pigments, and the color tone thereof is still unsatisfactory, and it has not been possible to produce gardenia blue pigments having a blue color tone which are bright to the same extent as edible blue No. 1 and spirulina pigments and have reduced reddish color.

Documents of the prior art

Patent document

Patent document 1: international publication No. 2006/82922

Patent document 2: international publication No. 2016/45100

Patent document 3: international publication No. 2017/156744

Patent document 4: international publication No. 2003/29358

Patent document 5: japanese laid-open patent publication No. 7-111896

Disclosure of Invention

The purpose of the present invention is to provide a gardenia blue pigment which exhibits a bright and clear blue hue with reduced redness, and a method for producing the same.

The present inventors have conducted extensive studies to solve the above problems, and as a result, have found that a gardenia blue pigment exhibiting a bright and sharp blue hue with reduced reddening can be obtained by performing a first step of reacting at least 1 peptide selected from the group consisting of a soybean peptide, a sesame peptide and a rice peptide with genipin in a solvent without supplying an oxygen-containing gas, and a second step of treating the reaction solution obtained in the first step with supplying an oxygen-containing gas. Further, it was found that the gardenia blue pigment obtained by performing the first and second steps was diluted with water to give a color value E^10％ _1cmIn the case of a 0.1 solution, L in the Lab color system^*The value is shown as a of 66 or more^*The value was-24 or less, and a color tone similar to that of food blue No. 1 was exhibited. Further, it was found that when the first step and the second step were carried out using rice peptide as an additive peptide, the obtained gardenia blue pigment exhibited not only a bright and clear blue color tone with reduced redness but also a color tone stably maintained even after heating under acidic conditions. The present invention has been completed through further studies based on these findings.

That is, the present invention provides the inventions of the following disclosed embodiments.

Item 1. A gardenia blue pigment which is diluted with water to give a color value E^10％ _1cmIn the case of a 0.1 solution, L in the Lab color system^*The value is shown as a of 66 or more^*The values are shown below-24.

Item 2. according to itemThe gardenia blue pigment of 1 which is diluted with water to prepare a color value E^10％ _1cmB in Lab color System in the case of 0.1 solution^*Values are shown above-30.

Item 3 the gardenia blue pigment according to item 1 or 2, wherein, when the operations shown in the following (1) to (3) are further performed, the color difference Δ E between the solution A which has been heat-treated at 90 ℃ for 15 minutes and the solution B which has not been heat-treated^* _abL of solution A which is 3.5 or less and heated at 90 ℃ for 15 minutes^*Value is shown as 64 or more, a^*Values shown below-14, b^*Values above-31 are shown.

< operating conditions >

(1) Preparation of

Diluting gardenia blue pigment with 0.1M citric acid buffer solution with pH of 2.5 to prepare color value E^10％ _1cmSolution A was 0.1. In addition, the gardenia blue pigment was diluted with a 0.1M citric acid buffer solution having a pH of 6.0 to prepare a color value E^10％ _1cmSolution B was 0.1.

(2) Heat treatment of the solution

The solution A was subjected to a heat treatment at 90 ℃ for 15 minutes. Solution B was not subjected to heat treatment.

(3) Measurement of color tone

L in the Lab color system was measured for the solution A which had been heat-treated at 90 ℃ for 15 minutes and the solution B which had not been heat-treated^*Value a^*Value b and^*the value is obtained.

The gardenia blue pigment according to any one of claims 1 to 3, wherein the maximum absorption wavelength of the gardenia blue pigment is in a region of 604nm or more.

A food or beverage according to claim 5, which is colored with the gardenia blue pigment according to any one of claims 1 to 4.

The method of producing gardenia blue pigment according to item 6, which comprises the following first step and second step.

A first step: at least 1 peptide selected from the group consisting of soybean peptide, sesame peptide and rice peptide was reacted with genipin in a solvent without supplying an oxygen-containing gas.

A second step: the reaction solution obtained in the first step is treated under the supply of a gas containing oxygen.

The production method according to item 6, wherein the proportion of peptides having a molecular weight of 2000 or less among the peptides is 45% or more, and the content of free amino acids is less than 20% by mass.

The method according to item 6 or 7, wherein in the first step, polyphenol is further present in the solvent.

The production method according to any one of claims 6 to 8, wherein air is used as the oxygen-containing gas.

According to the present invention, it is possible to produce a gardenia blue pigment exhibiting a bright and clear blue hue with reduced redness by a simple method. The gardenia blue pigment of the present invention is a natural pigment, but exhibits a blue color tone similar to that of edible blue No. 1, and therefore can be colored in a good color tone with high safety for various products such as food. In addition, the gardenia blue pigment of the present invention can maintain a clear blue color tone with brightness and reduced redness even when subjected to filtration treatment, heat sterilization treatment, drying treatment, etc., and thus can be easily manufactured and managed.

In addition, according to one embodiment of the present invention, a gardenia blue pigment is provided which has not only a bright, clear blue color tone with reduced redness, but also the characteristic of being able to stably maintain the color tone even after heating under acidic conditions, and therefore, can be colored in a good color tone even for acidic foods.

Detailed Description

1. Gardenia blue pigment

The gardenia blue pigment of the present invention is characterized in that it is diluted with water to give a color value E^10％ _1cmIn the case of a 0.1 solution, L in the Lab color system^*The value is shown as a of 66 or more^*The values are shown below-24. Hereinafter, the gardenia blue pigment of the present invention will be described in detail.

[ color tone characteristics ]

In the context of the present invention, the "color value E^10％ _1cm"is a unit indicating the color density of the dye, and is a value obtained by converting the absorbance at the maximum absorption wavelength measured by an absorbance meter using a cuvette having an optical path length of 1cm within a reliable concentration range into a value in a 10 wt% solution.

Since the maximum absorption wavelength of gardenia blue pigment is around 600nm, the color value E of gardenia blue pigment^10％ _1cmThe absorbance of the light can be determined by specifying the maximum absorption wavelength in the vicinity of 600nm and measuring the absorbance, but when the maximum absorption wavelength is not present, the absorbance at 600nm may be measured.

Color number E of gardenia blue pigment^10％ _1cmThe solution of 0.1 is prepared by diluting gardenia blue pigment with water (preferably ion-exchanged water). In the present invention, the color value E^10％ _1cmA color number of 0.1 means that the color number E is^10％ _1cmThe 4 th digit after the decimal point of (b) is rounded to 0.100.

The gardenia blue pigment of the invention is diluted by water to prepare a color value E^10％ _1cmIn the case of a 0.1 solution, L in the Lab color system (CIE L a b color system)^*The value was 66 or more, and a bright blue hue was exhibited. L is a value of L from the viewpoint of rendering a brighter blue tone^*The value is preferably 66 to 75, more preferably 67 to 75, and still more preferably 68 to 73.

The gardenia blue pigment of the invention is diluted by water to prepare a color value E^10％ _1cmIn the case of a 0.1 solution, a in the Lab color system^*The color of the composition showed a blue hue with little blushing, and the value was-24 or less. The a is a from the viewpoint of exhibiting a blue hue with further reduced reddening^*The value is preferably-35 to-24, more preferably-35 to-25, and still more preferably-32 to-26.

The gardenia blue pigment of the present invention is diluted with water to give a color value E^10％ _1cmB in Lab color system in the case of 0.1 solution^*The value is not particularly limited, and may be, for example, -30 or more. As b of^*Value, may be preferredIt is-27 or more, more preferably-25 or more, still more preferably-25 to-15, still more preferably-24 to-15, and particularly preferably-23 to-18.

C in Lab color system^*The value (Chroma) is represented by (a)^*Value of²+b^*Value of²)^1/2It was found that the gardenia blue pigment of the present invention has a color value E obtained by dilution with water^10％ _1cmC in Lab color system in the case of 0.1 solution^*Value (chroma) satisfying a^*Value b and^*the range of the value is, for example, 34 or more, preferably 35 to 40, more preferably 36 to 40, and still more preferably 37 to 40.

In the gardenia blue pigment of the present invention, the color value E is obtained by diluting with water^10％ _1cmH in Lab color System in 0.1 solution^*The value (Hue ) is not particularly limited, and is, for example, 230 or less, preferably 205 to 228, more preferably 205 to 225, and still more preferably 205 to 220.

The gardenia blue pigment of the present invention satisfying such a color tone can be obtained by the production method described later.

Further, the conventional gardenia blue pigment has a drawback that the reddish feeling becomes strong and the color tone changes if heated under acidic conditions, but in the production method described later, when rice peptide is used as the peptide to be added in the first step, it is possible to obtain a gardenia blue pigment having the above color tone, and having a characteristic of stably maintaining the color tone even after heating under acidic conditions (hereinafter, also referred to as "acid-resistant heating").

Specific examples of the gardenia blue pigment of the present invention having such acid-resistant heating properties include a color difference Δ E between a solution a subjected to heat treatment at 90 ℃ for 15 minutes and a solution B not subjected to heat treatment in the case where the operations shown in the following (1) to (3) are performed^* _abL of solution A which is 3.5 or less and heated at 90 ℃ for 15 minutes^*Value is shown as 64 or more, a^*Values shown below-14, b^*The value is indicated as gardenia blue pigment of-31 or more.

< operating conditions >

(1) Preparation of

Diluting gardenia blue pigment with 0.1M citric acid buffer solution with pH of 2.5 to prepare color value E^10％ _1cmSolution A was 0.1. In addition, the gardenia blue pigment was diluted with a 0.1M citric acid buffer solution having a pH of 6.0 to prepare a color value E^10％ _1cmSolution B was 0.1.

(2) Heat treatment of the solution

The solution A was subjected to a heat treatment at 90 ℃ for 15 minutes. Solution B was not subjected to heat treatment.

(3) Measurement of color tone

L in the Lab color system was measured for the solution A which had been heat-treated at 90 ℃ for 15 minutes and the solution B which had not been heat-treated^*Value a^*Value b and^*the value is obtained.

Regarding the color difference Δ E between the solution A which was heat-treated at 90 ℃ for 15 minutes and the solution B which was not heat-treated^* _abThe content is preferably 3.5 or less, and from the viewpoint of more excellent acid-resistant heating properties, it is preferably 3.0 or less, more preferably 0 to 2.5, and still more preferably 0 to 2.0.

L for solution A heated at 90 ℃ for 15 minutes^*The value is preferably 64 or more, and from the viewpoint of more excellent acid-resistant heating properties, it is preferably 65 or more, more preferably 65 to 70, and still more preferably 66 to 70.

A for solution A heated at 90 ℃ for 15 minutes^*The value is preferably-14 or less, and from the viewpoint of more excellent acid-resistant heating properties, it is preferably-15 or less, more preferably-26 to-16, and still more preferably-26 to-17.

B for solution A heated at 90 ℃ for 15 minutes^*The value is preferably-31 or more, more preferably-30 or more, still more preferably-29 to-22, and still more preferably-28 to-22, from the viewpoint of more excellent acid-resistant heating properties.

In the present invention, the above-mentioned values in the Lab color system are values measured by a spectrophotometer (CM-5KONICA MINOLTA JAPAN). The measurement conditions were as follows: the light source in the total transmission measurement is D65, the visual field is 10 ℃, the diameter phi of the measurement is 20mm, and the irradiation diameter phi is 26 mm.

Further, although the maximum absorption wavelength of the conventional gardenia blue pigment is in the vicinity of 600nm, the maximum absorption wavelength of the gardenia blue pigment of the present invention may be, for example, 604nm or more, preferably 605 nm or more, and more preferably 605 to 610 nm.

[ use ]

The gardenia blue pigment of the present invention is used as a blue colorant. The product to which the gardenia blue pigment of the present invention is applied is not particularly limited as long as the blue colorant is required to be used, and specific examples thereof include foods and drinks, cosmetics, oral agents, and pharmaceuticals. The gardenia blue pigment of the present invention is a natural source and has high safety, and therefore is particularly suitable as a colorant for foods and beverages.

The type of the food or drink to be colored with gardenia blue pigment of the present invention is not particularly limited as long as it is a food or drink which is required to be colored blue, and examples thereof include snacks such as jelly, chewing gum, soft candy, agar, cake, cookie, and candy in sheet form; japanese snacks such as dumpling, cake, fern cake, and stuffing; fruit processed products such as fruit jam; jam such as strawberry jam, blueberry jam, etc.; syrup; mirin, cooking wine, seasoning juice, sauce and other seasonings; frozen desserts such as ice cream, ice milk, ice dessert; dairy products such as yogurt, ice cream, fresh milk, etc.; aquatic product paste products such as fish cake, bamboo wheel, fish sausage, fish meat paste, etc.; bottling and canning livestock meat, fish meat, fruit, etc.; lactic acid bacteria beverage, refreshing beverage, carbonated beverage, fruit juice beverage, non-fruit juice beverage, fruit beverage, vegetable beverage, sport beverage, powder beverage, jelly beverage, alcoholic beverage, etc.; salted vegetables; and (5) flour.

In addition, when the gardenia blue pigment of the present invention has acid-resistant heating properties, it can be suitably used for acidic foods and beverages, particularly acidic foods and beverages that are sterilized by heat in the production process. In the present invention, acidic food and drink means food and drink having a pH of 5.0 or less.

When the gardenia blue pigment of the present invention has acid-heating resistance, the pH of the acidic food or beverage to be colored is not particularly limited as long as it is in the range of 5.0 or less, and even an acidic food or beverage having a pH of 4.0 or less, for example, can exhibit a stably maintained color tone. Specific examples of acidic foods and beverages include acidic beverages such as lactic acid bacteria beverages, refreshing beverages, carbonated beverages, fruit juice beverages, non-fruit juice beverages, fruit beverages, vegetable beverages, sports beverages, jelly beverages, and alcoholic beverages; dairy products such as yogurt, ice cream, fresh milk, etc.; desserts such as jelly; frozen desserts such as fruit juice, ice milk, and ice desserts; snacks such as soft sweets and jelly beans; jam such as strawberry jam, blueberry jam, etc.; juices such as fruit juices; salted vegetables; seasonings such as seasonings.

The cosmetic to be colored with gardenia blue pigment of the present invention is not particularly limited as long as it is a cosmetic which is required to be colored blue, and examples of the type of the cosmetic include basic cosmetics such as cream, lotion, beauty lotion, ointment, oil, pack, lotion, and gel; makeup cosmetics such as foundation, eye shadow, lipstick, and blush.

The oral preparation to be colored with gardenia blue pigment of the present invention is not particularly limited as long as it is an oral preparation which is required to be colored blue, and examples thereof include dentifrice such as a paste dentifrice, a powder dentifrice, and a liquid dentifrice; toothpaste; mouth washes such as mouth washes and gargles; oral paste, tooth-care spray, orally disintegrating film, gel, lozenge, tablet, chewable tablet, etc.

The drug to be colored with gardenia blue pigment of the present invention is not particularly limited as long as it is a drug which is required to be colored blue, and examples thereof include powders, granules, tablets, capsules, pills, and liquids.

The amount of gardenia blue pigment to be added to a product to be colored in the present invention may be appropriately set depending on the type of the product and the degree of coloring to be imparted to the product.

2. Preparation method of gardenia blue pigment

The method for producing gardenia blue pigment of the present invention is characterized by comprising the following first step and second step. Hereinafter, the method for producing gardenia blue pigment of the present invention will be described in detail.

A first step: at least 1 peptide selected from the group consisting of soybean peptide, sesame peptide and rice peptide was reacted with genipin in a solvent without supplying an oxygen-containing gas.

A second step: the reaction solution obtained in the first step is treated under the condition that a gas containing oxygen is supplied.

[ first step ]

Peptide (ii)

In the first step, at least 1 selected from the group consisting of soybean peptide, sesame peptide and rice peptide is used as the primary amino group-containing compound.

The soybean peptide is a peptide obtained by hydrolyzing a protein derived from soybean to reduce the molecular weight of the protein. The hydrolysis of the soybean-derived protein is not particularly limited, and may be carried out by a known method such as protease treatment, acid treatment, or alkali treatment. In addition, commercially available soybean peptides can be used.

The sesame peptide is a peptide obtained by hydrolyzing a protein derived from sesame to reduce the molecular weight. The hydrolysis of the sesame-derived protein is not particularly limited, and may be carried out by a known method such as protease treatment, acid treatment, or alkali treatment. In addition, commercially available sesame peptide can be used.

The rice peptide is a peptide obtained by hydrolyzing a protein derived from rice to lower the molecular weight of the protein. The hydrolysis of the rice-derived protein is not particularly limited, and may be carried out by a known method such as protease treatment, acid treatment, or alkali treatment. The rice peptide can be obtained from commercial products. In addition, as described above, when rice peptide is used as the primary amino group-containing compound, it is possible to produce gardenia blue pigment which not only exhibits bright and clear blue color tone with reduced reddening, but also has acid-resistant heating properties.

The average molecular weight of the soybean peptide, sesame peptide and rice peptide used in the present invention is not particularly limited, and may be, for example, about 5000 or less, preferably about 150 to 3000, and more preferably about 150 to 2000. The molecular weight distribution of the soybean peptide, the sesame peptide and the rice peptide is about 45% or more, preferably about 50 to 100%, and more preferably about 60 to 100% of the peptide having a molecular weight of 2000 or less. When the peptide having a molecular weight of 2000 or less is contained at such a ratio, the brightness of gardenia blue pigment can be further improved and the redness can be further reduced. In the present invention, the average molecular weight of the peptide is a weight average molecular weight calculated by gel filtration chromatography using HPLC using a peptide having a known molecular weight as a standard substance. The ratio of peptides having a molecular weight of 2000 or less is the ratio of the peak area of peptides having a molecular weight of 2000 or less to the total peak area.

In addition, free amino acids (amino acids that are present alone without binding to peptides) that are generated when hydrolyzing proteins may be present in a peptide. When a large amount of such free amino acids are contained in soybean peptide, sesame peptide, and rice peptide, the brightness of gardenia blue pigment may be reduced, and the reddish feeling may be enhanced. Therefore, the soybean peptide, the sesame peptide and the rice peptide used in the present invention are preferably small in free amino acid content, and for example, the content of free amino acid is less than 20% by mass, preferably 10% by mass or less, and more preferably 5% by mass or less.

Genipin (R)

Genipin is an aglycone of geniposide (iridoid glycoside) contained in fruits of gardenia jasminoides ellis belonging to Rubiaceae. Genipin can be obtained by allowing β -glucosidase to act on geniposide obtained by extraction treatment from fruits of gardenia jasminoides ellis belonging to the family rubiaceae.

The fruit of gardenia jasminoides ellis of the family rubiaceae used for the extraction of geniposide may be any of an undried product, a dried product or a frozen product, and may be a fruit obtained by cutting or pulverizing the fruit in order to improve the extraction efficiency.

Examples of the extraction solvent used for the extraction of geniposide include water, an organic solvent, and a mixed solvent thereof. The organic solvent is preferably a hydrophilic organic solvent, and examples thereof include monohydric alcohols having 1 to 5 carbon atoms (ethanol, methanol, propanol, isopropanol, etc.), polyhydric alcohols having 2 to 5 carbon atoms (glycerin, isopropylene glycol, propylene glycol, 1, 3-butylene glycol, etc.), esters (methyl acetate, etc.), ketones (acetone, etc.), and the like. Among these extraction solvents, water, lower monohydric alcohols and mixed solvents thereof are preferable from the viewpoints of safety and extraction efficiency of active ingredients; more preferred are water, ethanol and hydrous ethanol (mixed solvent of water and ethanol), and still more preferred is hydrous ethanol. When a mixed solvent of a lower monohydric alcohol and water is used as the solvent, the mixing ratio of the lower monohydric alcohol and water is not particularly limited, and for example, the concentration of the lower monohydric alcohol may be about 1 to 99 mass%, preferably about 40 to 90 mass%, and more preferably about 50 to 80 mass%.

The extraction method is not particularly limited as long as it is a general solvent extraction method, and examples thereof include a method of immersing the crude drug in an extraction solvent by cold immersion, warm immersion, or the like, and stirring it as necessary, and a diafiltration method.

The extraction solution obtained by the extraction treatment can be subjected to filtration, centrifugation, or the like as necessary to remove solid components, thereby recovering geniposide. The recovered geniposide may be subjected to purification treatment such as adsorption treatment or gel filtration, if necessary, to improve the purity.

The β -glucosidase used for producing genipin from geniposide may be any enzyme having β -glucosidase activity, and examples thereof include enzymes derived from Aspergillus niger (Aspergillus niger), Trichoderma reesei (Trichoderma reesei), Trichoderma viride (Trichoderma viride), and almond. Commercially available enzymes having β -glucosidase activity can be used. Examples of commercially available enzymes having β -glucosidase activity include Sumizyme C6000, Sumizyme AC, Sumizyme C, Sumizyme X, Sumizyme BGT, Sumizyme BGA (trade name; manufactured by Nippon chemical industries Co., Ltd.), CELLULOSIN AC40, CELLULOSIN T3, CELLULOSIN AL (trade name; manufactured by HBI Co., Ltd.) Onozuka 3S, Y-NC (trade name; manufactured by Yakult Pharmaceutical Industry Co., Ltd.), Cellulase A "AMANO" 3, and Cellulase T "AMANO" 4 (trade name; manufactured by Nayayaku Kogyo Co., Ltd.).

In order to allow β -glucosidase to act on geniposide to produce genipin, β -glucosidase and geniposide may be allowed to coexist under conditions in which β -glucosidase can act. The amount of the β -glucosidase to be used may be appropriately set according to conditions such as geniposide concentration, reaction temperature, and reaction time.

The temperature conditions for allowing β -glucosidase to act may be set as appropriate within the range of the temperature at which β -glucosidase acts, and examples thereof include about 30 to 60 ℃, preferably about 40 to 50 ℃.

The pH condition for allowing β -glucosidase to act may be set as appropriate within the pH range in which β -glucosidase acts, and examples thereof include about pH3.5 to 6.0, preferably about pH4.3 to 4.8.

Examples of the reaction solvent in the case where the β -glucosidase is allowed to act include water; phosphate buffer, citric acid buffer, Tris buffer, tartaric acid buffer, boric acid buffer, and the like.

The time for allowing the β -glucosidase to act may be appropriately set according to the amounts of the β -glucosidase and geniposide used, temperature conditions, and the like, and may be, for example, about 3 to 30 hours, preferably about 5 to 24 hours.

The reaction solution in which geniposide is produced by allowing β -glucosidase to act on geniposide may be used as it is in the first step as a geniposide-containing solution, or may be used in the first step in a state of being concentrated or dried by being subjected to purification treatment, concentration treatment, drying treatment, or the like as necessary.

Polyphenols

In the first step, the reaction may be carried out in the coexistence of the polyphenol, the specific peptide and genipin. Polyphenol refers to a compound having a plurality of phenolic hydroxyl groups in the molecule. The source of the polyphenol to be used is not particularly limited, and may be any of plant-derived polyphenols, polyphenols produced by microorganisms, chemically synthesized polyphenols, and the like.

The type of polyphenol is not particularly limited, and may be any of a flavonoid-based polyphenol or a non-flavonoid-based (phenolic acid-based) polyphenol. Examples of the flavonoid-based polyphenol include flavanones, flavones (フラボン syn), flavonols, flavanols, flavanonols, isoflavones, anthocyanins, chalcones, stilbenes, and the like.

Specific examples of flavanones include hesperidin, transglycosylhesperetin, hesperetin, naringin (ナリジン), and liquiritigenin. The transglycosylation hesperidin is a hesperidin derivative obtained by transferring a monosaccharide or oligosaccharide such as glucose, arabinose, galactose, rutinose, sophorose, glucuronic acid, etc. to the hydroxyl group of hesperidin, and specific examples thereof include α -monoglucosyl hesperidin, α -diglucosyl hesperidin, α -triglucosyl hesperidin, α -tetraglucosyl hesperidin, α -pentaglucosyl hesperidin, etc.

Specific examples of the flavonoid include flavone, apigenin, luteolin, apidine (apigenin), luteolin, and baicalein.

Specific examples of the flavonols include quercetin, kaempferol, and myricetin.

Specific examples of the flavanols include catechin (epicatechin, epicatechin gallate, epigallocatechin gallate, theaflavin, etc.), theaflavin, and anthocyanins.

Specific examples of flavanonols include alpintone (Alpinone) and taxifolin.

Specific examples of the isoflavones include genistein, daidzein, daidzin, glycitein, equol, biochanin a (biochanin a), coumestrol, puerarin, formononetin, and the like.

Specific examples of the anthocyanins include pelargonidin, anthocyanidin, petunidin, peony anthocyanin, petunidin (ペチュニジン), delphinidin, malvidin, and the like.

Specific examples of chalcones include carthamin and phloretin.

Specific examples of stilbenes include resveratrol.

Examples of the non-flavone-based polyphenol include ellagic acid, coumarin, curcumin, chlorogenic acid, lignan, sesamin, and the like.

These polyphenols may be used alone in 1 kind, or in combination in 2 or more kinds.

Among these polyphenols, flavanones are preferably mentioned, hesperidin, transglycosylated hesperetin and hesperetin are more preferred, and transglycosylated hesperetin is further preferred.

The polyphenol may be a purified polyphenol or a polyphenol (e.g., extract) in which other components are mixed.

Reaction of

In the first step, the specific peptide and genipin are allowed to coexist in a solvent without supplying a gas containing oxygen to cause a reaction.

The concentration of the specific peptide at the time of starting the reaction with genipin may be, for example, about 1 to 50% by mass, preferably about 5 to 30% by mass, and more preferably about 10 to 20% by mass of the specific peptide, and about 0.1 to 50% by mass, preferably about 1 to 20% by mass, and more preferably about 2.5 to 10% by mass of the genipin.

The ratio of genipin to the specific peptide at the start of the reaction is, for example, about 20 to 1000 parts by mass, preferably about 100 to 600 parts by mass, and more preferably about 200 to 300 parts by mass of the specific peptide relative to 100 parts by mass of genipin.

When polyphenols are also present, the concentration of the polyphenols at the time of starting the reaction is, for example, about 0.01 to 10% by mass, preferably about 0.025 to 5% by mass, and more preferably about 0.5 to 1% by mass. When polyphenols are also made to coexist, the ratio of genipin to polyphenol at the time of starting the reaction is, for example, about 0.2 to 220 parts by mass, preferably about 0.5 to 110 parts by mass, and more preferably about 1 to 22 parts by mass, relative to 100 parts by mass of genipin.

The pH at which the specific peptide is reacted with genipin is, for example, about 5 to 10, preferably about 6 to 9, and more preferably about 7 to 8. In addition, the reaction can be adjusted so as to be kept constant in these pH ranges.

Examples of the solvent for reacting the specific peptide with genipin include water; phosphate buffer, citric acid buffer, Tris buffer, tartaric acid buffer, boric acid buffer, and the like.

In the first step, the specific peptide and genipin may be reacted with each other in the presence of a solvent by, for example, adding genipin to a solution in which the specific peptide is dissolved, or adding the specific peptide to a solution in which genipin is dissolved. In addition, if a reaction solution (a liquid containing genipin) in which β -glucosidase is allowed to act to produce genipin is used, the specific peptide may be added to the reaction solution.

In the first step, the specific peptide and genipin are allowed to coexist in a solvent, and the reaction is performed without supplying a gas containing oxygen. The reaction can be carried out without supplying a gas containing oxygen, for example, by the following method: a method of performing smooth stirring to the extent that no air is introduced or leaving it to stand without stirring under an air atmosphere (hereinafter referred to as "method 1"); a method of stirring or standing in an atmosphere of inert gas such as nitrogen or argon; and a method of supplying an inert gas such as nitrogen or argon into the liquid. Among these methods, the method 1 is preferred because preparation of an inert gas and a special apparatus are not required, and the method is simple.

The temperature during the reaction in the first step is, for example, about 5 to 50 ℃, preferably about 10 to 45 ℃, and more preferably about 20 to 40 ℃.

The reaction time in the first step is, for example, about 1 hour or more, preferably about 3 to 24 hours, and more preferably about 5 to 20 hours.

[ second Process ]

In the second step, the reaction solution obtained in the first step is treated under the supply of a gas containing oxygen. The reaction solution obtained in the first step may be supplied to the second step as it is, or may be supplied to the second step after the pH is adjusted to about 5 to 10, preferably about 6 to 9, and more preferably about 7 to 8, as necessary. The reaction can be adjusted in such a way that it remains constant within these pH ranges.

The gas containing oxygen used in the second step may be oxygen itself, or a gas containing a gas component other than oxygen, such as air, may be used. From the viewpoint of reducing the production cost, air is preferably used as the gas containing oxygen.

The supply of the gas containing oxygen to the reaction solution obtained in the first step is performed by the following method: a method in which a gas containing oxygen is directly introduced into the reaction solution and stirred as necessary; and a method of stirring the reaction solution in an atmosphere of a gas containing oxygen so that the gas containing oxygen enters the reaction solution.

The amount of the gas containing oxygen may be set appropriately according to the size of the apparatus for performing the second step, the presence or absence of stirring in the supply of the gas containing oxygen, the stirring speed, and the like, as long as the amount is the same as the aerobic conditions (conditions at the time of color development) used in the production of conventional gardenia blue pigment, and for example, the amount of the gas containing oxygen may be 0.01 to 5.0vvm, preferably 0.05 to 2.5vvm, and more preferably 0.1 to 1.0 vvm. Here, the unit "vvm" of the supply amount of the oxygen-containing gas means the amount of the gas supplied in 1 minute per 1L of the reaction solution obtained in the first step. The supply amount of the oxygen-containing gas exemplified herein is the supply rate of the air itself. That is, for example, when pure oxygen is used as the gas containing oxygen, the air may contain about 20% by volume of oxygen, and thus the amount of oxygen may be 20% by volume of the supply amount.

The temperature at which the oxygen-containing gas is supplied is, for example, about 5 to 50 ℃, preferably about 10 to 45 ℃, and more preferably about 20 to 40 ℃. The temperature in the second step may be constant or may vary within these ranges during the reaction.

In the second step, the supply of the oxygen-containing gas may be performed until the color value of the solution becomes constant, or may be stopped at a point when a desired color tone appears. Specifically, the supply time of the oxygen-containing gas is 1 hour or more, preferably about 3 to 120 hours, more preferably about 6 to 50 hours, and further preferably about 12 to 40 hours.

By performing the second step in this manner, the gardenia blue pigment is produced which exhibits a bright and clear blue color tone with reduced reddening. The reaction solution after the second step may be used as it is as a gardenia blue pigment solution, or may be subjected to refining treatment, concentration treatment, drying treatment, etc. as necessary to prepare a gardenia blue pigment concentrated solution or dried product.

Examples

The present invention will be described in detail below with reference to examples and the like, but the present invention is not limited to these examples.

Test example 1

1. Production of gardenia blue pigment (Using fermenter) (examples 1-1 to 1-3 and comparative examples 1-1 to 1-15)

(1) Preparation of genipin

First, geniposide solution (color value E) extracted and purified from fruit of Gardenia jasminoides Ellis of Rubiaceae is prepared^10％ _1cm1335.48, the measurement wavelength was 238 nm; geniposide content of about 45 mass%). 11.0g of cellulase (Sumizyme C, 1500U/g, Nippon chemical Co., Ltd.) having β -glucosidase activity was dissolved in 110g of purified water, and 110g of the geniposide solution (color value E at the start of the reaction) was added^10％ _1cmAt 245, a measurement wavelength of 238 nm; at the beginning of the reactionThe concentration of geniposide is about 0.2 mol/L). Then, after the pH of the solution was adjusted to 4.5, an enzyme reaction was performed at 50 ℃ for 18 hours to obtain a genipin-containing liquid (post-reaction solution).

(2) Reaction without oxygen supply

Sodium monohydrogen phosphate dihydrate 5.5g, trisodium phosphate (anhydrous) 4.27g, and the peptide or amino acid shown in table 1 76.1g were added to water 283g and dissolved. The obtained solution was mixed with the genipin-containing liquid (total amount) obtained above, and the pH was further adjusted to 7.5. The resulting solution was transferred to a 1L fermentor (BMJ-01 NC: ABLE Co., Ltd.), and allowed to react for 15 hours under slow stirring conditions at 35 ℃ without introducing air.

(3) Reaction under oxygen supply

After the reaction solution was adjusted to pH7.0 without supplying oxygen, the reaction was carried out at 35 ℃ and 420rpm with stirring until the color value was raised smoothly while supplying air at a supply rate of 0.25 vvm. The reaction time varies depending on the type of peptide or amino acid used, and is 24 to 48 hours. Thus, a liquid (solution after reaction) containing gardenia blue pigment was obtained.

2. Measurement of color tone of gardenia blue pigment

Filtering the obtained liquid containing gardenia blue pigment, diluting the pigment liquid without insoluble substances with ion-exchanged water to prepare color value E^10％ _1cmIs a 0.1 solution. The color tone of the solution was measured using a spectrophotometer (CM-5KONICAMINOLTAJAPAN Co., Ltd.). In the total transmission measurement, the light source was set to D65, the visual field was set to 10 ℃, the measurement diameter was φ 20mm, and the irradiation diameter was φ 26 mm. For reference, the color value E was obtained by diluting edible blue No. 1 with ion-exchanged water^10％ _1cmThe color tone of the 0.1 solution was also measured in the same manner.

The obtained results are shown in table 1. As a result, it was confirmed that the peptide was obtained by mixing soybean peptide, sesame peptide or rice peptide with BeijingThe color value E of gardenia blue pigment obtained by reacting nipine without supplying air and then reacting nipine with air^10％ _1cmWhen a solution of 0.1 is prepared, L^*The value is shown above 66, and a^*The color of the pigment showed a clear blue color tone of-24 or less, which was bright and reduced in redness, and the color tone was closer to that of the edible blue No. 1 than that of the conventional gardenia blue pigment (examples 1-1 to 1-3). On the other hand, when produced under the same conditions using peptides or amino acids other than soybean peptide, sesame peptide and rice peptide, the color turns into a reddish blue (a)^*High value), the color tone was not close to that of edible blue No. 1 (comparative examples 1-1 to 1-15).

[ Table 1]

"Soybean peptide (Hinute AM, manufactured by shinko Co., Ltd.)" of #1 had a free amino acid content of 2% by mass, and the peak area of the peptide having a molecular weight of 2000 or less was 78.1% of the total peak area in the analysis results by gel filtration chromatography using HPLC.

#2 As to "sesame peptide (sesame peptide KM-20, Tanshan pharmaceutical Co., Ltd)", the peak area of the peptide having a molecular weight of 2000 or less was 90% or more of the total peak area in the analysis result by gel filtration chromatography using HPLC.

#3ΔE^* _abThe value represents the color difference with reference to food blue No. 1 (reference example).

Further, the gardenia blue pigment-containing liquid obtained in examples 1-1 to 1-3 was filtered, and the insoluble matter-removed pigment liquid was diluted with ion-exchanged water to prepare a color value E^10％ _1cmIs a 0.05 solution. The color tone of the solution was measured using an ultraviolet-visible spectrophotometer (manufactured by JASCO, V750) equipped with an integrating sphere. The obtained results are shown in table 2. From these results, it was also confirmed that the gardenia blue pigment obtained in examples 1-1 to 1-3 exhibited a bright and clear blue color tone with reduced reddening.

[ Table 2]

Test example 2

1. Production of gardenia blue pigment (Using fermenter) (examples 2-1 to 2-5)

Gardenia blue pigment was produced by the same method as in test example 1 above except that the soybean peptide shown in Table 3 was used in the reaction under the condition of no oxygen supply.

2. Measurement of color tone of gardenia blue pigment

The color tone of the gardenia blue pigment obtained was measured under the same conditions as in test example 1. The obtained results are shown in table 3. From the results, it was confirmed that when a predetermined peptide was reacted with genipin without supplying air and then reacted under supplying air, gardenia blue pigment having a good color tone with suppressed reddening was obtained with a lower free amino acid content of the peptide used.

[ Table 3]

The ratio (%) of peptides having a molecular weight of 2000 or less is a value obtained by obtaining the ratio of the peak area of peptides having a molecular weight of 2000 or less to the total peak area of peptides from the results of analysis by gel filtration chromatography using HPLC.

Test example 3

1. Production of gardenia blue pigment (Using fermenter) (examples 3-1 to 3-3 and comparative example 3-1)

Gardenia blue pigment was produced in the same manner as in test example 1 except that soybean peptide (Hinute AM, manufactured by shinko Co., Ltd.) was used as the peptide to be added, and the reaction time was changed to 0 hour (comparative example 3), 4 hours (example 3-1), 5 hours (example 3-2) and 22 hours (example 3-3) without supplying oxygen.

2. Production of gardenia blue pigment (Using fermenter) (comparative example 3-2)

(1) Preparation of genipin

A liquid containing genipin was prepared under the conditions shown in test example 1 above.

(2) Reaction under oxygen supply

Sodium monohydrogen phosphate dihydrate 5.5g, trisodium phosphate (anhydrous) 4.27g, and the peptide or amino acid shown in Table 4 76.1g were added to water 283g and dissolved. The obtained solution was mixed with the genipin-containing liquid (total amount) obtained above, and the pH was further adjusted to 7.5. The resulting solution was transferred to a 1L-volume fermentor, and while supplying air to the solution at a supply rate of 0.25vvm, the reaction was carried out under stirring conditions of 35 ℃ and 420rpm until the color value was raised smoothly. The reaction time was 33 hours.

(3) Reaction without oxygen supply

After the reaction liquid after the reaction under the condition of supplying oxygen was adjusted to pH7.0, the reaction was carried out for 18 hours under a slow stirring condition without introducing air at 35 ℃. Thus, a liquid (solution after reaction) containing gardenia blue pigment was obtained.

3. Measurement of color tone of gardenia blue pigment

The color tone of the gardenia blue pigment obtained was measured under the same conditions as in test example 1. The obtained results are shown in table 4. In Table 4, the color value E adjusted by diluting the food blue No. 1 with ion-exchanged water¹⁰％_1cmThe color tone of the 0.1 solution was also measured in the same manner. From the results, it was also confirmed that when a predetermined peptide was reacted with genipin without supplying air and then reacted with genipin with supplying air, a gardenia blue pigment exhibiting a clear blue color tone with bright and reduced reddening was obtained.

In addition, even when a predetermined peptide and genipin were reacted under the condition of supplying air and then the reaction was carried out under the condition of not supplying air, it was not possible to obtain a gardenia blue pigment exhibiting a clear blue color tone with brightness and reduced reddening.

[ Table 4]

#ΔE^* _abThe value represents the color difference with reference to food blue No. 1 (reference example).

Test example 4

1. Production of gardenia blue pigment (Using fermenter) (example 4-1)

Gardenia blue pigment was produced in the same manner as in test example 1 except that soybean peptide (Hinute AM, manufactured by shinko corporation) was used as the added peptide, and 1.2G of transglycosylhesperidin (α -triglucose hesperidin content: 85% by mass, α G hesperidin PA-T, manufactured by kazaki corporation) was added to the solution subjected to the reaction under the condition of no oxygen supply.

2. Preparation of gardenia blue pigment (Using flask) (example 4-2)

(1) Preparation of genipin

First, geniposide solution (color value E) extracted and purified from fruit of Gardenia jasminoides Ellis of Rubiaceae is prepared^10％ _1cmAt 1240, the wavelength was determined to be 238 nm; geniposide content of about 45 mass%). 3.56g of cellulase (Sumizyme C, 1500U/g, Nippon chemical Co., Ltd.) having β -glucosidase activity was dissolved in 39.11g of purified water, and 35.5g of the geniposide solution (color value E at the start of the reaction) was added^10％ _1cmAt 245, a measurement wavelength of 238 nm; geniposide concentration of about 0.2 mol/L). Then, after the pH of the solution was adjusted to 4.5, an enzyme reaction was performed at 50 ℃ for 18 hours to obtain a genipin-containing liquid (post-reaction solution).

(2) Reaction without oxygen supply

1.65G of monosodium phosphate dihydrate, 1.28G of trisodium phosphate (anhydrous), 22.83G of soybean peptide (Hinute AM, manufactured by shin-shi oil Co., Ltd.), and 0.18G of transglycosylhesperidin (content of. alpha. -triglucosyl hesperidin 85 mass%;. alpha. -G hesperidin PA-T, Kawasaki Geigoni K.K.) were added to 75G of water and dissolved therein. The obtained solution was mixed with the genipin-containing liquid (total amount) obtained above, and the pH was further adjusted to 7.5. The resulting solution was transferred to a 300mL beaker, sealed, and reacted at 35 ℃ with stirring (magnetic stirrer) at 100rpm for 18 hours without aeration.

(3) Reaction under oxygen supply

After the reaction under the condition of not supplying oxygen, the reaction solution was adjusted to pH7.0, and then transferred to a 500mL flask, and the flask mouth is opened to the air atmosphere, at 35 degrees C, stirring 150rpm under conditions of reaction for 30 hours until the color value to reach a smooth rise. Thus, a liquid (solution after reaction) containing gardenia blue pigment was obtained.

3. Measurement of color tone of gardenia blue pigment

The color tone of the obtained gardenia blue-containing liquid was measured by the same method as in test example 1. The obtained results are shown in table 5. Table 5 also shows the color value E adjusted by diluting food blue No. 1 with ion-exchanged water^10％ _1cmThe color tone of the solution was measured at 0.1. This result confirmed that even when transglycosylation hesperidin was added when soybean peptide was reacted with genipin without supplying oxygen, gardenia blue pigment having a bright and bright blue color with reduced reddening could be obtained by reacting with air after the reaction without supplying air.

The maximum absorption wavelength of the gardenia blue pigment of example 4-1 was 605.5nm, and the maximum absorption wavelength of the gardenia blue pigment of example 4-2 was 608.0 nm.

[ Table 5]

#ΔE^* _abThe value represents the color difference with reference to food blue No. 1 (reference example).

Test example 5

1. Production of gardenia blue pigment (Using flask) (reference example 1)

Gardenia blue pigment was produced by the method of example 2 described in patent document 3 (international publication No. 2017/156744). Specifically, 0.6g of genipin (purity 98%, Kyokushi food Co., Ltd.), 9mL of 99.5% ethanol, and 2.05g of sodium glutamate monohydrate were dissolved in water. The obtained solution was put into a flask, put into a water bath at 75 ℃ and reacted for 6 hours under 150 strokes/min. Removing ethanol in the reacted reaction solution by an evaporator, and freeze-drying to obtain powdery gardenia blue pigment.

2. Measurement of color tone of gardenia blue pigment

The color value E adjusted by diluting the obtained gardenia blue pigment with ion-exchanged water was prepared^10％ _1cmThe color tone of the solution was measured using a spectrophotometer (CM-5KONICA MINOLTA JAPAN Co., Ltd.) for 0.0337. In the total transmission measurement, the light source was set to D65, the visual field was set to 10 ℃, the measurement diameter was φ 20mm, and the irradiation diameter was φ 26 mm. For reference, a color value E was prepared by diluting the gardenia blue pigment-containing liquid obtained in example 1-1 with ion-exchanged water^10％ _1cmThe color tone of the solution was measured in the same manner as in the 0.0337 solution.

The results are shown in Table 6. As a result, it was confirmed that a is a for gardenia blue pigment obtained by the method of patent document 3^*The color tone was reddish with a high value.

[ Table 6]

Test example 6

1. Production of gardenia blue pigment (Using flask) (examples 5-1 and 5-2)

(1) Preparation of genipin

First, geniposide solution (color value E) extracted and purified from fruit of Gardenia jasminoides Ellis of Rubiaceae is prepared^10％ _1cm1335.48, the measurement wavelength was 238 nm; geniposide content of about 45 mass%). 4.17g of cellulase (Sumizyme C, 1500U/g, Nippon chemical Co., Ltd.) having β -glucosidase activity was dissolved in 41.67g of purified water, and 41.67g of the geniposide solution (color value E at the start of the reaction) was added^10％ _1cmAt 245, a measurement wavelength of 238 nm; geniposide concentration of about 0.2 mol/L). Then, after the pH of the solution was adjusted to 4.5, an enzyme reaction was performed at 50 ℃ for 18 hours to obtain a genipin-containing liquid (post-reaction solution).

(2) Reaction without oxygen supply

Sodium hydrogen phosphate monohydrate 1.65g, trisodium phosphate (anhydrous) 1.28g, and rice peptide (rice peptide powder, Wuhan Tiantianhao biological products Co., Ltd.) 22.83g were added to water 75g and dissolved. The obtained solution was mixed with the genipin-containing liquid (total amount) obtained above, and the pH was further adjusted to 7.5. The resulting solution was transferred to a 300mL beaker, sealed, and reacted at 35 ℃ with stirring (magnetic stirrer) at 100rpm for 18 hours in an unvented state.

(3) Reaction under oxygen supply

The reaction solution after the reaction without supplying oxygen was adjusted to pH7.0 and transferred to a 500 mL-volume flask, and the reaction was carried out at 35 ℃ under stirring at 150rpm for 48 hours with the flask mouth open to the air atmosphere until the color value was raised smoothly. Thus, a liquid (solution after reaction) containing gardenia blue pigment was obtained.

2. Determination of acid-resistant heating property of gardenia blue pigment

A solution A (color value E) was prepared by diluting the obtained gardenia blue pigment-containing liquid with 0.1M citric acid buffer solution having a pH of 2.5^10％ _1cm0.1). Separately, a solution B (color value E) was prepared by diluting the obtained gardenia blue pigment-containing liquid with 0.1M citric acid buffer solution having a pH of 6.0^10％ _1cm0.1). After the solutions A and B were allowed to stand at 5 ℃ for about 18 hours, the solution A was subjected to heat treatment at 90 ℃ for 15 minutes. The solution B was not subjected to heat treatment. The solutions A and B were centrifuged at 3000rpm for 10 minutes by a centrifuge, and the absorbance of the supernatant at the maximum absorption wavelength near 600nm was measured. The ratio of the absorbance of the solution A to that of the solution B was determined as 100%, and the ratio was determined as the residual ratio of the solution A after heat treatment at 90 ℃ for 15 minutes at a pH of 2.5.

The color tones of the solution A after the heat treatment and the solution B without the heat treatment (after leaving at 5 ℃ C. for about 18 hours) were measured by a spectrophotometer (CM-5KONICAMINOLTA JAPAN Co., Ltd.). In the total transmission measurement, the light source was set to D65, the visual field was set to 10 ℃, the measurement diameter was φ 20mm, and the irradiation diameter was φ 26 mm.

The results are shown in Table 7. According to the results, gardenia blue pigment obtained by reacting rice peptide with genipin under the condition of not supplying oxygen and then under the condition of supplying oxygen is set to 2.5 even though pH is set (color value E)^10％ _1cm0.1) is heated, L^*Also has a value of 64 or more, a^*Has a value of-14 or less, and b^*A value of-31 or more, and further a value corresponding to the unheated condition of pH6.0 (color value E)^10％ _1cmIs 0.1) comparison,. DELTA.E^* _abAlso 3.5 or less, and has excellent resistance to heat by acid heating.

[ Table 7]

#ΔE^* _abThe value represents the color difference with respect to the solution B which was not subjected to the heat treatment.

Test example 7

1. Gardenia jasminoides ellisProduction of blue pigment (Using flasks) (comparative examples 7-1 to 7-5)

Gardenia blue pigment was produced under the same conditions as in example 5-1 except that the peptides or amino acids shown in Table 8 were used instead of the rice peptide.

2. Determination of acid-resistant heating property of gardenia blue pigment

The heat resistance was measured under the same conditions as in test example 6. The results are shown in Table 8. As a result, it was confirmed that the gardenia blue pigment obtained could not be heat-resistant even when the peptide other than the rice peptide was reacted with genipin without supplying air and then the reaction was performed under the condition of supplying air.

[ Table 8]

#ΔE^* _abThe value represents the color difference with respect to the solution B which was not subjected to the heat treatment.