JP5650356B2 - Red pigment and method for producing the same - Google Patents

Description

  The present invention relates to a red pigment excellent in acid resistance using an iridoid compound and a protein hydrolyzate, and a method for producing the same.

  Conventionally, gardenia red pigments have been widely used as red pigments for food pigments. Gardenia red pigment is generally obtained by reacting an aglycone of an iridoid compound obtained by extraction from the fruit of Rubiaceae gardenia and a primary amino group-containing substance under acidic conditions. Other examples of red pigments include various pigments such as Benikouji pigment, cochineal pigment, safflower red pigment, anthocyanin pigment, and beet pigment. However, cochineal pigments are derived from insects, safflower red pigments are insoluble in water and have poor heat resistance, anthocyanin pigments cannot be used in a neutral pH range, and beet pigments have poor heat resistance. Therefore, there are difficulties such as limited foods that can be used. As an alternative, gardenia red pigment has attracted attention. Various dyes that produce red color by reacting an iridoid compound with a protein hydrolyzate and methods for producing the same have been proposed (for example, Patent Documents 1, 2, and 3).

  Patent Documents 1 and 2 disclose a method of producing a red pigment by reacting an iridoid compound having a carboxyl group at the 4-position of an iridoid skeleton with a protein hydrolyzate. The amino acid content with respect to the dry weight is 35% by weight or more, 50% by weight or more of the amino acids is glutamic acid and aspartic acid, and the ratio of the weight of leucine to the total weight of glutamic acid and aspartic acid is 8% or less. It is characterized by this.

  Patent Document 3 discloses a protein hydrolyzate containing a substance having a carboxyl group at the 4-position of an iridoid skeleton in an iridoid glycoside (eg, geniposide acid) and an amino group amount in the range of 30 to 60 per total nitrogen amount. (For example, a commercially available wheat protein hydrolyzate having an amino group content of 40.7 per total nitrogen amount) and an organic acid (for example, citric acid) are prepared, and β-glucosidase is added to the aqueous solution. The gardenia red pigment | dye whose content of the component with a molecular weight of 440,000 or more obtained by adding and carrying out an enzymatic hydrolysis reaction is 50% or more is disclosed.

Japanese Patent No. 4526600

Japanese Patent No. 4605824

JP 2011-217728 A

  However, the applicant has found that the red pigment using the iridoid compound of the above-mentioned patent document exhibits a good red color in the neutral range, but is insolubilized and unstable in the acidic range. I found it inferior.

  Therefore, the present invention aims to provide a red dye using an iridoid compound that can maintain stable color development even in an acidic solution and is more excellent in light resistance in a neutral to acidic range, and a method for producing the same. To do.

The method for producing a red pigment of the present invention is a method for producing a red pigment by reacting an iridoid compound having a carboxyl group at the 4-position of an iridoid skeleton with a protein hydrolyzate, wherein the protein hydrolyzate includes A total ratio of alanine, glycine and proline in the total amino acid composition contained in the degradation product is 50 % by weight or more , and an average molecular weight of 700 or more and 1400 or less is used.

  A collagen hydrolyzate can be used as the protein hydrolyzate, and fish scales may be used as the collagen.

The red pigment of the present invention is a red pigment containing hydroxyproline produced by reacting an iridoid compound with a proteolysate having an average molecular weight of 700 or more and 1400 or less, in the total amino acid composition contained in the pigment. The total content of alanine, glycine, proline and hydroxyproline is 50 % by weight or more.

The red pigment of the present invention is a red pigment produced by reacting an iridoid compound with a degradation product of collagen having an average molecular weight of 700 or more and 1400 or less, alanine, glycine in the total amino acid composition contained in the pigment, The total content of proline and hydroxyproline is 50 % by weight or more.

The red pigment of the present invention is a red pigment produced by reacting an iridoid compound with a protein hydrolyzate having an average molecular weight of 700 or more and 1400 or less , and is contained in the decomposition product as the protein hydrolyzate. alanine to total amino acid composition, the total proportion of glycine and proline are used not less than 50 wt%, alanine at all containing amino acid composition contained in the dye, glycine, total 50 weight of proline and content of the hydroxyproline % Or more.

  According to the present invention, it is possible to provide a red pigment having excellent acid resistance using the iridoid compound and the protein hydrolyzate.

  Hereinafter, the details of a method for producing a red pigment by reacting an iridoid compound having a carboxyl group at the 4-position of the iridoid skeleton with a protein hydrolyzate will be described.

  As the iridoid compound having a carboxyl group at the 4-position of the iridoid skeleton of the present invention, for example, geniposide acid or geniposide acid aglycone can be used. Geniposide acid is obtained from the fruit extract of gardenia. Gardenia fruit extract contains many compounds having a carboxyl group at the 4-position of the iridoid skeleton represented by geniposide acid. Gardenia fruit extract can be obtained, for example, by ester hydrolysis of geniposide obtained by extraction with dry ethanol or water from dried gardenia fruit.

  Moreover, although the substance which hydrolyzed arbitrary proteins can be used as the protein hydrolyzate of this invention, Preferably, it is sufficient to use animal protein, especially the hydrolyzate of collagen. Collagen is obtained by extracting from the skin of livestock such as cows and pigs, and the skin and scales of fish such as flounder, salmon, sea bass and tilapia. It is also possible to use fibroin obtained from rice husk or the like as the protein hydrolyzate. In the present invention, the protein hydrolyzate may contain substances other than primary amino group-containing compounds such as excipients, moisture, and sodium chloride.

  The protein hydrolyzate is a protein hydrolyzed by an arbitrary method, and contains a primary amino group-containing compound including a free amino acid and a peptide. The pigment component of gardenia red pigment is a product obtained by reacting the above-mentioned iridoid compound and the above-mentioned protein hydrolyzate by an arbitrary method. The amino acid composition and content in the present invention are those obtained by decomposing the above-mentioned protein hydrolyzate and pigment component of gardenia red pigment into free amino acids by an arbitrary method, for example, by the following method.

Below, an example of the total amino acid measuring method of a protein degradation product is shown.
(1) Pretreatment Proteolysate decomposed by an arbitrary method is pulverized by freeze-drying, 20 mg of the powder sample and 2 ml of 6N-hydrochloric acid are placed in a hydrolysis tube, sealed, and subjected to hydrolysis at 110 ° C. for 22 hours. Do. After cooling and opening the tube, it is concentrated to dryness in a rotary evaporator and dried in a vacuum desiccator containing sodium hydroxide for 15 hours. This is added and dissolved in 20 ml of a mobile phase for HPLC measurement to obtain a sample for amino acid analysis.

(2) Method for measuring total amino acids of proteolysate Using the following apparatus, instrument, and reagent, measurement is performed with the following settings.
Apparatus: Shimadzu HPLC amino acid analysis system Precolumn: Shim-pack ISC-30Na / S0504 (Na)
Guard column: Shim-pack ISC-07 (Na)
Column: Shim-pack Amino-Na
Flow rate: 0.4 ml / min
Injection volume: 5 μl
Column temperature: 60 ° C
Detector: Fluorescence detection EX 350 nm, EM 450 nm
Mobile phase: Mobile phase kit for amino acid analysis Na type Reaction solution: Reaction solution kit for amino acid analysis OPA reagent Standard amino acid solution: Amino acid mixed solution (H type manufactured by Wako Pure Chemical Industries) 10-fold dilution

  In addition, although the amino acid in this invention is a general term for the organic compound which has a functional group of both an amino group and a carboxyl group, in the measuring method of this invention, alanine (Ala), arginine (Arg), aspartic acid ( Asp), cysteine (Cys), glutamic acid (Glu), glycine (Gly), histidine (His), isoleucine (Ile), leucine (Leu), lysine (Lys), methionine (Met), phenylalanine (Phe), proline ( Pro), serine (Ser), threonine (Thr), tryptophan (Trp), tyrosine (Tyr), valine (Val) and hydroxyproline (Hyp). In the measurement method of the present invention, asparagine (Asn) is measured as aspartic acid, and glutamine (Gln) is measured as glutamic acid.

  Although the manufacturing method of protein hydrolyzate is arbitrary, an example of the manufacturing method which produces | generates the protein hydrolyzate from dried scales is shown.

  Add water to the dried scales and swell sufficiently. As the dry scale serving as the substrate, for example, scales of strawberry and tilapia are used. The ratio of the substrate (dried scale) to water may be about 5 to 50% by weight (hereinafter, “%” means “% by weight”), preferably 10 to 20%. The swelling is preferably performed for about 1 hour under the condition of heating to such an extent that water does not boil. For hydrolysis of scale, any method of enzyme, acid and alkali hydrolysis may be used, but it is preferable to use an enzyme hydrolysis reaction.

  Enzymatic hydrolysis can be carried out by a conventional method, but a proteolytic enzyme is added to the scale swelling liquid and reacted with stirring. The type of proteolytic enzyme is arbitrary, but neutral protease is preferred. For example, protease A “Amano” SD, Bromelain F (Amano Enzyme Co., Ltd.), Sumiteam LP, Sumiteam FP (Shin Nihon Chemical Industry Co., Ltd.), Neutase (Novozymes Japan Co., Ltd.), Orientase 90N ( HIBIAI Co., Ltd.), Aroase NS (Yakult Pharmaceutical Co., Ltd.), and Papain (Kyowa Hakko Bio Co., Ltd.) can be used. The amount of the proteolytic enzyme added, the reaction temperature, and the reaction time are arbitrary, but it is preferably carried out under appropriate conditions for the proteolytic enzyme used, but the average molecular weight of the protein hydrolyzate is about 200 to 1800, preferably about 700 to 1400. It is preferable to be controlled.

  The resulting hydrolyzate of protein hydrolyzate is heated to inactivate the proteolytic enzyme. The heating temperature / time may be any temperature / time at which the enzyme becomes inactive.

  The obtained protein hydrolyzate may be used for the reaction of gardenia red pigment as it is, but can also be used as a concentrated solution and powder. Any method may be used for the production method related to concentration and powder.

  By the above process, a protein (fish collagen) hydrolyzate using fish scales as a raw material is obtained. The temperature, time, and amount of each substance added in the above steps are such that the average molecular weight of the obtained protein hydrolyzate is controlled to 200 to 1800, preferably 700 to 1400, and glycine, alanine, and proline occupying all the contained amino acids. The total content is controlled to be 30% or more, preferably 40% or more.

  When a red pigment was experimentally prepared using a dried scale and a hydrolyzate of commercially available gelatin, the results shown in Table 1 were obtained. Based on this result, it can be seen that the average molecular weight of the protein hydrolyzate is preferably controlled to about 200 to 1800, preferably about 700 to 1400.

In addition, the measurement of the average molecular weight of protein hydrolyzate is performed by the following method, for example.
(1) Preparation of gel filtration chromatography test solution Proteolysate decomposed by any method is pulverized by freeze-drying, 100 mg of the powder sample is dissolved in 10 ml of purified water, and filtered through a 0.45 μm membrane filter. And a test solution for gel filtration chromatography for average molecular weight measurement.

(2) Gel Filtration Chromatography Measurement Conditions for Proteolytic Product Device: Waters Alliance HPLC system Column: TSK-GEL G250PWXL Inner diameter 7.8 mm, length 300 mm
Flow rate: 0.5 ml / min
Column temperature: 40 ° C
Injection volume: 5 μl
Detector: UV (measurement wavelength 210 nm)
Mobile phase: Water / acetonitrile / TFA = 55/45 / 0.1 mixed solution Analysis: Empower2 chromatography manager

The following substances were used as molecular weight markers. (Molecular weight in parentheses)
Gly (75)
Thyrotropin Release Home (362)
Bombesin (1620)
Glucagon (3483)
Insulin (5700)
Aprotinin (6511)

Moreover, the measurement of the average molecular weight of the production | generation red pigment | dye of Table 1 is performed by the following method, for example.
(1) Preparation of Gel Filtration Chromatography Sample Solution of Gardenia Red Dye Component The reacted gardenia red pigment was arbitrarily diluted with the following mobile phase so that Abs at 530 nm was 5.0, and the 0.45 μm membrane filter was used. Filter to obtain a test solution for gel filtration chromatography for measuring average molecular weight.

(2) Gel filtration chromatography measurement conditions of gardenia red pigment component Apparatus: Waters Alliance HPLC system Column: Shodex Asahipak GS-620HQ
Inner diameter 7.8mm, length 300mm
Flow rate: 0.5 ml / min
Column temperature: 40 ° C
Injection volume: 5 μl
Detector: VIS (measurement wavelength 530 nm)
Mobile phase: 0.1 N sodium acetate buffer (pH 5.5, containing 0.2 M sodium chloride)
Analysis: Empower2 Chromatography Manager

The following substances were used as molecular weight markers. (Molecular weight in parentheses)
BSA (669K)
Apoferritin (443K)
Ferritin (440K)
β-Amylase (200K)
Aldolase (158K)
Conalbumin (75K)
Ovalbumin (44K)
Carbon Abydrase (29K)
Cytchrome C (12.4K)
Aprotinin (6.5K)

  The reaction of the gardenia red pigment with the iridoid compound having a carboxyl group at the 4-position of the iridoid skeleton and the protein hydrolyzate in the production method of the present invention may employ various conventional methods.

  As described above, geniposide is extracted from gardenia fruits using water or alcohol. Here, geniposide prepared as a concentrate or powder was used. Hydrolysis may be performed according to a conventional method, and is usually performed by adding an alkali or an acid to the geniposide solution, or using an appropriate hydrolase. In this embodiment, sodium hydroxide is added. In this case, the geniposide solution is prepared so that the concentration of geniposide is 1 to 50%, preferably about 5 to 15%. Sodium hydroxide is preferably added so that the pH of the geniposide solution is 9.0 to 13.0, and the heating is performed at room temperature to 90 ° C. The pH is preferably 10.0 to 12.0, the reaction temperature is 40 to 60 ° C., and the reaction time is 1 to 24 hours.

  By adding an inorganic acid such as hydrochloric acid or an organic acid such as citric acid to the resulting hydrolyzed geniposide solution, the liquidity is adjusted to pH 7.0 or lower, preferably pH 5.0 or lower, thereby reducing the geniposide ester. A liquid containing geniposide acid which is a hydrolyzate is prepared.

  The method for producing gardenia red pigment of the present invention is not particularly limited as long as it includes a step of allowing a sugar hydrolase (β-glucosidase) to act on the solution containing the geniposide acid in the presence of the above-mentioned protein hydrolyzate. . Any sugar hydrolase can be used, but an enzyme preparation having β-glucosidase activity is preferably used. Specifically, Sumiteam AC, Sumiteam BGA (Shin Nihon Chemical Industry Co., Ltd.), Cellulase “Onozuka” 12S, Cellulase Y-2NC (Yakult Pharmaceutical Co., Ltd.), Aromase (Amano Enzyme Co., Ltd.) may be used. it can.

  In addition, the said reaction can perform an enzyme process at pH (3-6) in which (beta) -glucosidase can act, and temperature (40-80 degreeC). The reaction time is preferably in the range of 24 to 72 hours. Moreover, although it is preferable to carry out under the anaerobic conditions under inert gas, such as nitrogen gas, there is no restriction | limiting in particular in anaerobic conditions.

  As preferable production conditions of the present invention, geniposidic acid is 5 to 30%, preferably 10 to 15%, and the above-mentioned collagen protein degradation product is 5 to 20% in 100% by weight (hereinafter referred to as%) of the reaction solution. It is preferable to adjust to 8 to 15% and organic acid to 2 to 20%, preferably 8 to 15%. The amount of β-glucosidase added is 0.01 to 5.0%, preferably 0.1 to 1.0%.

  The enzyme is inactivated by heating the reaction solution at 70 to 120 ° C., preferably 80 to 100 ° C. for 0.3 to 3 hours, preferably 0.5 to 1 hour. The obtained pigment is subjected to purification steps such as centrifugation, filtration, adsorption resin, membrane purification, etc., as necessary, and an optional concentration treatment or powder treatment is performed to complete a red pigment as a product.

  The red pigment thus obtained has a total content of alanine, glycine, proline and hydroxyproline in the total amino acid content of 40% or more, preferably 50% or more. In addition, the color tone is bright and the acid resistance is excellent. In addition, compared with conventional products, excellent effects are also seen in terms of heat resistance and light resistance.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

<Production example of collagen hydrolyzate>
200 kg of water was added to 15 kg of dried scale (Fish Collagen Peptan F 2000LD (known trade company)), and the mixture was swelled at 50 ° C. for 1 hour, followed by heat treatment at 90 ° C. for 30 minutes. 75 g of protease A “Amano” SD was added to the swollen solution cooled to 50 ° C., and the mixture was stirred for 36 hours while maintaining the temperature at 50 ± 2 ° C. After that, sterilization treatment was performed at 90 ° C. for 1 hour to deactivate the enzyme. This reaction solution was filtered, concentrated and dried to obtain 10.9 kg of protein hydrolyzate powder using scale collagen as a raw material. The average molecular weight of the protein hydrolyzate was around 1060, which was the same as the fish collagen degradation product 5 in Table 1.

  The composition of the protein hydrolyzate produced in the above production example was as shown in Tables 2 and 3. As shown in Table 1, the total content of glycine, alanine and proline in all the amino acids contained in the protein hydrolyzate of Production Example was 40% or more.

In Tables 2 and 3, values obtained by investigating the composition of the following commercially available protein hydrolyzate are listed.
Fish skin ... HDL-30DR (Nitta Gelatin Co., Ltd.)
Beef bones S-4 (Nitta Gelatin Co., Ltd.)
Pork bone ... GBL-100 (Nitta Gelatin Co., Ltd.)
Pig skin ... 800F (Nitta Gelatin Co., Ltd.)
Milk ... Far East Peptone (Kyokuto Pharmaceutical Co., Ltd.)
Soybean ... High New R (Fuji Oil Co., Ltd.)
Wheat ... Pro Extract HVP-G (Banshu Seasoning Co., Ltd.)
Corn ... Pro Extract G2 (Banshu Seasoning Co., Ltd.)

単位：ｍｇ／１００ｇ

Unit: mg / 100g

計１：タンパク分解物の全アミノ酸中のプロリン、グリシン及びアラニンの占める割合

Total 1: Proline, glycine and alanine occupying the total amino acids of proteolysate

<Example 1>
Sodium hydroxide was added to 78 kg of a geniposide solution having a geniposide concentration of 10.8% to adjust the solution pH to 12.0. After stirring at 60 ° C. for 2 hours, citric acid was added to adjust the pH to 4.5. To this solution was added 5.7 kg of the protein hydrolyzate powder of fish collagen (scale collagen) described above, and then cellulase “Onozuka” 12S was added, and the enzyme reaction was performed at 60 ° C. for a total of 48 hours under a nitrogen atmosphere. Make red color. This solution was filtered, subjected to membrane purification, and concentrated to adjust the color value to 50 to obtain 35 kg of the red pigment of the example.

<Example 2>
90 g of water was added to 10 g of HDL-30DR (Nitta Gelatin Co., Ltd.), which is a fish skin collagen, and stirred and dissolved at 50 ° C. for 1 hour, followed by heat treatment at 90 ° C. for 30 minutes. Sumiteam FP (0.1 g) was added to the solution cooled to 45 ° C., and the mixture was stirred for 24 hours while maintaining the temperature at 45 ° C. After that, heat treatment was performed at 90 ° C. for 1 hour to inactivate the enzyme. Separately, 100 g of a geniposide solution adjusted to 10% was adjusted to pH 12.0 by adding a 24% sodium hydroxide solution, stirred at room temperature overnight, and then adjusted to pH 4.5 by adding citric acid. To this, the entire amount of the fish skin collagen degradation product prepared above was mixed, 0.05 g of Sumiteam BGA was further added, and an enzyme reaction was performed at 50 ° C. for 36 hours under a nitrogen atmosphere to develop a red color. This solution was heated at 90 ° C. for 1 hour and then cooled to room temperature to obtain 200 g of a red pigment having a color value of 14.5.

<Example 3>
Using beef bone gelatin S-4 (Nitta Gelatin Co., Ltd.) as a raw material, 200 g of red pigment having a color value of 17.3 was obtained in the same manner as in Example 2.

<Example 4>
Using pork bone gelatin GBL-100 (Nitta Gelatin Co., Ltd.) as a raw material, 200 g of red pigment having a color value of 17.8 was obtained in the same manner as in Example 2.

<Example 5>
Using pig skin gelatin 800F (Nitta Gelatin Co., Ltd.) as a raw material, 200 g of red pigment having a color value of 16.3 was obtained in the same manner as in Example 2.

<Comparative Example 3>
90 g of water is added to 10 g of milk-derived proteolysate, Far Eastern Peptone (Kyokuto Pharmaceutical Co., Ltd.), which is a commercially available protein hydrolyzate, and after stirring and dissolving at 50 ° C. for 1 hour, heat treatment is performed at 90 ° C. for 30 minutes. Cooled to 45 ° C. Separately, 100 g of a geniposide solution adjusted to 10% was adjusted to pH 12.0 by adding a 24% sodium hydroxide solution, stirred at room temperature overnight, and then adjusted to pH 4.5 by adding citric acid. To this, the whole amount of the milk-derived proteolysate solution prepared above was mixed, 0.05 g of Sumiteam BGA was further added, and an enzyme reaction was carried out at 50 ° C. for 36 hours under a nitrogen atmosphere to develop a red color. This solution was heated at 90 ° C. for 1 hour and then cooled to room temperature to obtain 200 g of a red pigment having a color value of 12.5.

<Comparative example 4>
200 g of a red pigment having a color value of 13.3 was obtained in the same manner as in Comparative Example 3, using High Newt R (Fuji Oil Co., Ltd.), a soybean-derived protein hydrolyzate that is a commercially available protein hydrolyzate.

<Comparative Example 5>
Using wheat proteolysate pro-extract HVP-G (Banshu Seasoning Co., Ltd.), which is a commercially available protein hydrolyzate, 200 g of red pigment having a color value of 15.7 was obtained in the same manner as in Comparative Example 3. .

<Comparative Example 6>
A corn-derived proteolysate pro-extract G2 (Banshu Seasoning Co., Ltd.), which is a commercially available protein hydrolyzate, was used as a raw material to obtain 200 g of a red pigment having a color value of 15.5 in the same manner as in Comparative Example 3.

  The amino acid composition of this example was as shown in Tables 4 and 5. In Tables 4 and 5, the compositions of red pigments produced using other protein hydrolysates and red pigments manufactured by other companies as comparative examples are also described as reference examples. Comparative Example 1 is Gardenian Red-N- (L) manufactured by Mitsui Sugar Co., Ltd., and Comparative Example 2 is Riquet Color SGR-20 manufactured by Riken Vitamin Co.

単位：ｍｇ／１００ｇ

Unit: mg / 100g

計２：各原料由来の分解物を使用した生成赤色素の全アミノ酸組成中のプロリン、グリシン、アラニン及びヒドロキシプロリンの占める割合

Total 2: Ratio of proline, glycine, alanine and hydroxyproline in the total amino acid composition of the red pigment produced using the degradation products derived from each raw material

  As shown in these tables, the total content of alanine, glycine, proline and hydroxyproline in all the amino acids contained in the red pigment of the example was 50% or more.

  Measurement of all amino acids of the red pigment may be performed, for example, by the following method. For Example 1 and Comparative Examples 1 and 2, a gardenia red pigment was dissolved in 2.0 ml of purified water in an amount corresponding to 20 g with a color value of 2.5, and used as a sample for measuring gardenia red pigment-constituting amino acids. 1 ml of gardenia red pigment solution obtained by the above operation and 1 ml of 12N-hydrochloric acid are added to the hydrolysis tube, pretreatment and HPLC analysis are performed in the same manner as the measurement of the composition of the protein hydrolyzate, and gardenia red Measure the constituent amino acids.

  For example, Examples 2 to 4 and Comparative Examples 3 to 6 may be purified by the following procedures to purify gardenia red pigment from the reaction solutions of various protein degradation products. An amount corresponding to 20 g with a color value of 2.5 was adjusted, and the dye solution filtered through a 0.45 μm membrane filter was added to Amicon (registered trademark) Ultra-0.5 ml (Ultracel (registered trademark) -3K, Merck Millipore Ltd.). ) And centrifugal separation at 15,000 rpm for 10 minutes to collect components that have not passed through the membrane. The recovery rate of gardenia red pigment component by this operation was 92% or more. By repeating these operations, the gardenia red pigment component corresponding to 20 g with a color value of 2.5 is purified and concentrated. This purified and concentrated gardenia red pigment is further washed and purified with 1.5 ml of purified water, and the purified red pigment is dissolved in 2.0 ml of purified water to obtain a sample for measuring amino acids constituting gardenia red pigment.

  The color tone, acid resistance, heat resistance and light resistance of Examples 1 to 5 and Comparative Examples 1 to 6 were compared with other red pigments. The comparison results are shown below.

  Table 6 shows a comparison of transmitted light color differences of aqueous solutions in which Examples 1 to 5 and Comparative Examples 1 to 6 were each adjusted with a pH 4.0 buffer to a Abs 530 nm reading of 0.5. Here, L, a, and b are coordinate values in the Lab color space, where L is lightness, a is redness, and b is blueness. Munsell is a tone value by the Munsell color system. According to this, Examples 1-5 are a color tone comparable with Comparative Examples 1-6. In particular, Example 1 is an intermediate color tone of Comparative Example 1 of reddish purple and Comparative Example 2 of reddish purple, and has a color tone specific to gardenia red pigment.

  These aqueous solutions were subjected to a resistance test and a light resistance test under the following conditions. The dyes of Example 1 and Comparative Examples 1 to 6 were added to two types of citrate buffers at pH 3.0 and pH 5.0. In order to make the conditions the same, Examples 1 to 5 and Comparative Examples 1 to 6 were arbitrarily diluted with each citrate buffer so that Abs at 530 nm was around 0.5.

  What heated this solution for 30 minutes at 90 degreeC was compared as the acid-proof sample of Examples 1-5 and Comparative Examples 1-6, respectively. Moreover, after heating this solution at 90 degreeC for 30 minutes and irradiating 6000 lux white light for 3 days and 5 days, it compared as the light-resistant sample of Examples 1-5 and Comparative Examples 1-6, respectively.

  These comparison results are shown in Tables 7 and 8. In these tables, the absorbance at the time of dilution adjustment, the absorbance after heating, after 3 days of irradiation and after 5 days of irradiation, the presence or absence of precipitation, and the residual rate are described. Regarding the acid resistance test results by dilution and heating at pH 3.0, Examples 1 to 5 show almost no fading even at pH 3.0, but Comparative Examples 1 to 6 indicate that the dye component is insoluble by heating after dilution. And became precipitated. Moreover, about the subsequent light resistance test result, although Examples 1-5 have some fading, they are not insolubilized and are maintaining the color close | similar to the original, In Comparative Examples 1-6, the pigment component insolubilizes and precipitates. It remained.

  Moreover, about the acid resistance and light resistance test results at pH 5.0, Examples 1-5 were found to have superior acid resistance equal to or higher than that of Comparative Examples 1-6.

ｐＨ３．０緩衝液中での耐酸性及び耐光性比較結果

Comparison of acid and light resistance in pH 3.0 buffer

ｐＨ５．０緩衝液中での耐酸性及び耐光性比較結果

Comparison of acid resistance and light resistance in pH 5.0 buffer

  Table 9 shows the results of separately conducted acid resistance, heat resistance and light resistance tests. In this test, the following processing was performed on Comparative Example 7 and 8 which are the same products as Comparative Example 1 and Example 6, and Comparative Example 1 and 2 manufactured in the same manner as in Example 1. The dyes of Example 6 and Comparative Examples 7 and 8 were added to five types of solutions adjusted to pH 3.0, pH 3.5, pH 4.0, pH 5.0, and pH 7.0 with sodium citrate. In order to make the conditions the same, Example 6 (color value 50) was added by 0.10%, Comparative Example 7 (color value 100) was added by 0.05%, and Comparative Example 8 (color value 50) was added by 0.10%. .

  These solutions heated at 90 ° C. for 30 minutes were compared as acid-resistant samples of Example 6, Comparative Examples 7 and 8, respectively. Moreover, what heated these solutions at 90 degreeC for 2 hours was compared as a heat-resistant sample under the acidic conditions of Example 6, Comparative Examples 7 and 8, respectively. In addition, these solutions were heated at 90 ° C. for 30 minutes and then irradiated with white light of 6000 lux for 3 days, and were compared as light-resistant samples under the acidic conditions of Example 6 and Comparative Examples 7 and 8, respectively. .

  In Table 9, with respect to the acid resistance test results, although Example 6 shows almost no fading even when the pH decreases, Comparative Examples 7 and 8 show fading as the pH decreases, and Comparative Example When pH 7 was reached, the pigment became insoluble and precipitated at pH 3, and Comparative Example 8 was precipitated at pH 3.5 because the pigment was unnecessary. As for the heat resistance test results, the color fading (heat resistance) due to heat in Example 6 and Comparative Examples 7 and 8 is almost the same as long as the comparison is made in the pH range where Comparative Examples 7 and 8 do not precipitate. Furthermore, as for the light resistance test results, although Example 6 has a slight color fading, the color is almost the same as the original, but Comparative Examples 7 and 8 are largely faded.

  From these results, Example 6 is excellent in acid resistance and light resistance. Further, the heat resistance is equal to or higher than that of the comparative example.

Claims (7)

A method of producing a red pigment by reacting an iridoid compound having a carboxyl group at the 4-position of an iridoid skeleton with a protein hydrolyzate,
As the protein hydrolyzate, a total ratio of alanine, glycine and proline in the total amino acid composition contained in the decomposed product is 50 % by weight or more , and an average molecular weight of 700 or more and 1400 or less is used. A method for producing a red pigment.   The method for producing a red pigment according to claim 1, wherein a collagen hydrolyzate is used as the protein hydrolyzate.   The method for producing a red pigment according to claim 2, wherein fish scales are used as the collagen. The red pigment | dye manufactured with the manufacturing method in any one of Claims 1 thru | or 3 . A red pigment containing hydroxyproline produced by reacting an iridoid compound with a proteolytic product having an average molecular weight of 700 or more and 1400 or less ,
A red pigment, wherein the total content of alanine, glycine, proline and hydroxyproline in the composition of all contained amino acids contained in the pigment is 50 % by weight or more. A red pigment produced by reacting an iridoid compound with a degradation product of collagen having an average molecular weight of 700 or more and 1400 or less ,
A red pigment, wherein the total content of alanine, glycine, proline and hydroxyproline in the composition of all contained amino acids contained in the pigment is 50 % by weight or more. A red pigment produced by reacting an iridoid compound with a protein hydrolyzate having an average molecular weight of 700 or more and 1400 or less ,
As the protein hydrolyzate, one having a total ratio of alanine, glycine and proline in the total amino acid composition contained in the decomposed product is 50 % by weight or more,
A red pigment, wherein the total content of alanine, glycine, proline and hydroxyproline in the composition of all contained amino acids contained in the pigment is 50 % by weight or more.