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 山下顺也 西川正洋 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即使在酸性条件下的加热后也能够稳定地维持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,能够得到即使在酸性条件下的加热后也能够稳定地维持色调的栀子蓝色素,所述第一工序是使核桃肽、苦瓜肽、和/或大豆肽与京尼平在溶剂中在不供给包含氧气的气体的条件下进行反应,所述第二工序是对上述第一工序中得到的反应液在包含氧气的气体的供给下进行处理。(The purpose of the present invention is to provide gardenia blue pigment which can stably maintain the color tone even after heating under acidic conditions, and a method for producing the same. A gardenia blue pigment which can maintain a stable color tone even after heating under acidic conditions can be obtained by performing a first step of reacting a walnut peptide, a momordica charantia peptide and/or a soybean peptide with genipin in a solvent without supplying a gas containing oxygen and a second step of treating the reaction solution obtained in the first step with supplying a gas containing oxygen.)

1. A gardenia blue pigment having a color difference Delta E between a solution A which has been heat-treated at 90 ℃ for 15 minutes and a solution B which has not been heat-treated in the case where the operations (1) to (3) below 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 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％ _1cmSolution B at 0.1;

(2) heating treatment of the solution:

heating the solution A at 90 ℃ for 15 minutes, and not heating the solution B;

(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.

2. A food or beverage colored with the gardenia blue pigment according to claim 1.

3. The food or drink according to claim 2, wherein the food or drink is an acidic food or drink.

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

a first step in which at least 1 selected from the group consisting of a walnut peptide, a momordica peptide and a soybean peptide is reacted 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.

5. The manufacturing method according to claim 4, wherein air is used as the gas containing oxygen.

Technical Field

The present invention relates to gardenia blue pigment which can maintain a stable color tone even after heating under acidic conditions. In addition, the invention relates to a preparation method of the gardenia blue pigment.

Background

Conventionally, gardenia blue pigment, which is a natural pigment, has been widely used as a blue colorant used in foods and the like. The gardenia blue pigment is prepared from iridoid glycoside obtained by allowing beta-glucosidase and a compound containing primary amino group to act on fruits of gardenia belonging to family Rubiaceae under aerobic conditions. However, the gardenia blue pigment obtained by such a production method has a disadvantage that it turns reddish and changes in color tone when heated under acidic conditions. Therefore, when conventional gardenia blue is used for acidic foods and beverages, the color tone of the gardenia blue is strong in reddening after heat sterilization even if the color tone is desired before heat sterilization, and thus the range of use is limited.

Therefore, various techniques have been studied for improving the stability of gardenia blue pigment under acidic conditions.

For example, patent document 1 discloses that gardenia blue pigment which can be stably dissolved in an acidic region can be obtained by subjecting iridoid glycoside to β -glucosidase treatment in the presence of a protein decomposition product derived from silk. However, the gardenia blue pigment described in patent document 1 has a color tone with a strong reddish feeling, and has a problem that the color tone changes greatly due to a further increase in the reddish feeling after heating under acidic conditions.

Patent document 2 discloses that addition of gum ghatti and/or gum arabic to gardenia blue can impart acid resistance. However, the gardenia blue pigment described in patent document 2 cannot suppress the change in color tone after heating under acidic conditions.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2017-63650

Patent document 2: japanese patent laid-open publication No. 2015-91946

Disclosure of Invention

The purpose of the present invention is to provide gardenia blue pigment which can stably maintain the color tone even after heating under acidic conditions, 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 gardenia blue pigment capable of stably maintaining a color tone even after heating under acidic conditions can be obtained by performing a first step of reacting walnut peptide, momordica charantia peptide and/or soybean peptide with genipin in a solvent without supplying a gas containing oxygen, and a second step of treating the reaction solution obtained in the first step with supplying a gas containing oxygen.

Further, it was found that the gardenia blue pigment obtained by performing the first and second steps had a color difference Δ E between the solution A which had been heat-treated at 90 ℃ for 15 minutes and the solution B which had not been heat-treated, when the operations shown in the following (1) to (3) were 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^*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

For solution A, heat treatment was carried out at 90 ℃ for 15 minutes. For solution B, no heat treatment was performed.

(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 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 has a color difference Δ E between a solution A which has been heat-treated at 90 ℃ for 15 minutes and a solution B which has not been heat-treated 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^*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 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.

Item 2. A food or beverage colored with the gardenia blue pigment according to item 1.

The food or drink according to item 3, 2, wherein the food or drink is an acidic food or drink.

Item 4. a method for producing gardenia blue pigment, which comprises:

a first step in which at least 1 selected from the group consisting of a walnut peptide, a momordica peptide and a soybean peptide is reacted with genipin in a solvent without supplying a gas containing oxygen;

and a second step of treating the reaction solution obtained in the first step with a gas containing oxygen.

Item 5. the production method according to item 4, wherein air is used as the oxygen-containing gas.

According to the present invention, gardenia blue pigment which can stably maintain the color tone even after heating under acidic conditions can be produced by a simple method. Further, since the gardenia blue pigment of the present invention is a natural pigment, it is highly safe for acidic foods and can be colored in a good color tone.

Detailed Description

1. Gardenia blue pigment

The gardenia blue pigment of the present invention is characterized in that 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 in the case of performing the operations shown in (1) to (3) described later^* _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. Hereinafter, the gardenia blue pigment of the present invention will be described in detail.

In the present specification, the characteristic of stably maintaining the color tone even after heating under acidic conditions may be referred to as "acid-heating resistance".

[ acid-resistant heating ]

The gardenia blue pigment of the invention has excellent acid-resistant heating performance, and specifically has the following characteristics: when the following operations were performed, the color difference Δ E between the solution A which had been heat-treated at 90 ℃ for 15 minutes and the solution B which had not been heat-treated was measured^* _abL of solution A which is 3.5 or less and heated at 90 ℃ for 15 minutes^*A value of 64 or more, a^*A value of-14 or less, and b^*The value is-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 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.

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. In the present invention, E^10％ _1cmA color number of 0.1 means that the color number E is^10％ _1cmThe 4 th bit after the decimal point of the value of (b) is rounded to 0.100.

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.

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 not less than 64, but preferably not less than 65 from the viewpoint of more excellent acid-resistant heating propertyMore 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, more preferably-15 or less, still more preferably-26 to-16, and still more preferably-26 to-17, from the viewpoint of more excellent acid-resistant heating properties.

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.

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

[ 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.

The pH of the acidic food or beverage to be colored with gardenia blue pigment of the present invention is not particularly limited as long as it is in the range of 5.0 or less, and for example, even an acidic food or beverage having a pH of 4.0 or less 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.; sauces such as fruit sauces; 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 its kind is not particularly limited, and examples thereof include basic cosmetics such as cream, lotion, beauty lotion, ointment, oil, pack, emulsion, gel, and the like; 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: reacting at least 1 selected from the group consisting of walnut peptide, momordica charantia peptide and soybean peptide with genipin in a solvent under the condition that a gas containing oxygen is not supplied.

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

[ first step ]

Juglans regia, Momordica charantia and/or Soy peptides

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

Walnut peptide is a peptide obtained by hydrolyzing a protein derived from walnut to reduce the molecular weight. The hydrolysis of the protein derived from walnuts is not particularly limited, and may be carried out by a known method such as protease treatment, acid treatment, or alkali treatment. The walnut peptide can be a commercial product.

Momordica charantia peptide is a peptide obtained by hydrolyzing a protein derived from Momordica charantia to lower the molecular weight of the protein. The hydrolysis of the protein derived from momordica charantia is not particularly limited, and may be performed by a known method such as protease treatment, acid treatment, or alkali treatment. The Momordica charantia peptide can be commercially available.

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 average molecular weight of the walnut peptide, the momordica peptide and the soybean peptide used in the present invention is not particularly limited, and examples thereof include 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, further improvement in the brightness of gardenia blue pigment and further reduction in redness can be achieved. 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.

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 preferred from the viewpoint of safety and extraction efficiency of the active ingredient; 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 a purification treatment such as adsorption treatment or gel filtration as 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 subjected to purification treatment, concentration treatment, drying treatment, or the like as necessary to prepare a concentrated solution or a dried product.

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.

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. The reaction can be adjusted in such a way that it remains constant within 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 preferable 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.

In order to supply a gas containing oxygen to the reaction solution obtained in the first step, the reaction is carried out 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 oxygen-containing gas to be supplied may be the same as the aerobic conditions (conditions during color development) used in the production of conventional gardenia blue pigment, and may be appropriately set depending on the size of the apparatus for performing the second step, the presence or absence of stirring in the oxygen-containing gas supply, the stirring speed, and the like, and examples of the amount of oxygen to be supplied include 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 to the reaction solution obtained in the first step for 1 minute per 1L. The supply amount of the oxygen-containing gas exemplified herein is the supply rate of the air itself. That is, for example, if pure oxygen is used as the oxygen-containing gas, the oxygen may be supplied in an amount of 20% by volume of the supply amount because about 20% by volume of oxygen is contained in the air.

The temperature of the reaction solution when the gas containing oxygen 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 gardenia blue pigment having the acid-resistant heating property is produced, and the supply time of the oxygen-containing gas may be appropriately set according to the supply rate, the reaction temperature, and the like of the oxygen-containing gas. For example, when walnut peptide and/or momordica charantia peptide is used, the reaction is carried out until the color value of the reaction solution rises smoothly, and the supply time of the gas containing oxygen is specifically 20 to 120 hours, preferably 30 to 100 hours, and more preferably 40 to 80 hours. In addition, for example, in the case of using soybean peptide, gardenia blue pigment having acid-resistant heating property may not be produced at the time when the rise of the color value of the reaction liquid becomes smooth, and therefore, it is desirable to continue the supply of the oxygen-containing gas after the rise of the color value of the reaction liquid becomes smooth, and the supply time of the oxygen-containing gas is specifically 40 to 140 hours, preferably 50 to 130 hours, and more preferably 60 to 120 hours.

By performing the second step in this manner, the gardenia blue pigment having acid-resistant heating properties is produced. The reaction solution obtained in the second step may be used as it is as a gardenia blue pigment solution, or may be subjected to purification treatment, concentration treatment, drying treatment, or the like as needed 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 (examples 1-1 to 1-3)

(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

1.65g of monosodium hydrogen phosphate dihydrate, 1.28g of trisodium phosphate (anhydrous), and 22.83g of walnut peptide (walnut peptide powder, wuhan tiantian good biological products limited), momordica charantia peptide (momordica charantia peptide powder, wuhan tiantian good biological products limited), or soybean peptide (HINUTE AM, shinshui oil corporation) were added to 75g of water 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

After the reaction solution after the reaction without supplying oxygen was adjusted to pH7.0 (examples 1-1, 1-3 and 1-4) or pH5.0 (example 1-2), the reaction solution was transferred to a 500 mL-capacity flask, and the reaction was carried out at 35 ℃ for 120 hours (examples 1-2 and 1-4) or 48 hours (examples 1-1 and 1-3) under stirring at 150rpm with the mouth of the flask opened to the air atmosphere. Thus, a liquid (solution after reaction) containing gardenia blue pigment was obtained.

2. Test of acid-and heat-resistance of gardenia blue pigmentStator

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 of pH6.0^10％ _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 in the case of heat treatment at 90 ℃ for 15 minutes at pH 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-5KONICA MINOLTA JAPAN Co., Ltd.). The measurement conditions were set to light source D65, a visual field of 10 ℃ and a measurement diameter φ 20mm and an irradiation diameter φ 26mm in the total transmission measurement.

The results are shown in Table 1. According to the results, gardenia blue pigment obtained by reacting a walnut peptide, a momordica charantia peptide or a soybean peptide with genipin under oxygen-free conditions and then under oxygen supply was adjusted to pH2.5 (color value E)^10％ _1cm0.1) heating, 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, even with the condition of pH6.0 without heating (color value E)^10％ _1cmIs 0.1) comparison,. DELTA.E^* _abIs 3.5 or less, and also has excellent resistance to heat by acid.

[ Table 1]

#ΔE^* _abValue expressed as the value of the area not heatedThe solution B was the color difference value at the time of calibration.

Test example 2

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

Gardenia blue pigment was produced under the same conditions as in example 1-1 above, except that the peptides or amino acids shown in Table 2 were used instead of walnut peptides.

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

The heat resistance was measured under the same conditions as in test example 1. The results are shown in Table 2. As a result, it was confirmed that the gardenia blue pigment obtained could not be heated with acid resistance even when genipin was reacted with a peptide other than walnut peptide, momordica peptide and soybean peptide without supplying air and then subjected to a reaction with supplying air.

[ Table 2]

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