JP2009065898A - Gold nanocolloid aqueous dispersing liquid for food and drink - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gold nanocolloid aqueous dispersing liquid for food and drink, extremely effective for coloring food and drink. <P>SOLUTION: This gold nanocolloid aqueous dispersing liquid for food and drink contains gold particles, and at least one kind of a protective material selected from the group consisting of gelatin, collagen, and collagen peptide. A method for producing the gold nanocolloid aqueous dispersing liquid is also provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a gold nanocolloid dispersion for food and drink and a method for producing the dispersion.

  As colorants used for the purpose of enhancing the commercial value of food and drink, organic and inorganic dyes, pigments (hereinafter referred to as colorants) that are harmless to the human body are generally used. On the other hand, unlike these colorants, attempts have been made to color food and drink with a solution containing gold particles by utilizing the color developed by gold plasmon absorption (Patent Document 1).

  However, the gold particles are very likely to aggregate, and if the concentration of gold in the solution becomes high, the gold particles precipitate in the solution without being dispersed, and cannot be used as a colorant. For example, the gold concentration of the colloidal gold solution disclosed in Patent Document 1 is a low concentration of 0.0001 to 0.1% by weight. In order to sufficiently color food and drink using such a low concentration colloidal gold solution, it is necessary to add a large amount of gold colloid solution to the food and drink.

  Moreover, in the method of patent document 1, nonionic surfactants, such as polyoxyethylene and hydrogenated hydrogenated castor oil, are used, and the taste and food texture of food may be inhibited.

Under such circumstances, the gold nanocolloid aqueous dispersion for coloring foods and drinks that stably disperses the gold particles in the solution and does not impair the taste and texture of the food, even if it has a high concentration of gold particles. Liquid is sought.
Japanese Patent Laid-Open No. 7-204493 JP-A-5-236907

  This invention makes it a subject to provide the gold | metal nanocolloid aqueous dispersion for food-drinks effective in coloring of food-drinks.

  The present inventors have intensively studied in order to solve the above problems. As a result, even when gold particles are contained at a high concentration in the solution by reducing the gold compound using a specific reducing agent and further using a specific protective agent (dispersing agent), It was found that they do not aggregate in an aqueous solution and are stably dispersed uniformly. Moreover, since the obtained gold nanocolloid aqueous dispersion has gold particles dispersed at a high concentration, the food and drink can be sufficiently colored by adding a small amount to the food and drink. It was found that the feeling and the like were not impaired. The present invention has been completed based on such findings.

The present invention relates to an aqueous gold nanocolloid dispersion for food and drink as shown in the following items 1 to 9 and a method for producing the dispersion.
Item 1. A gold nanocolloid aqueous dispersion for food and drink, comprising gold particles and at least one protective agent selected from the group consisting of gelatin, collagen and collagen peptides.
Item 2. Item 2. The gold nanocolloid aqueous dispersion for food or drink according to Item 1, wherein the protective agent is a collagen peptide having a molecular weight of 500 to 10,000.
Item 3. Item 3. The gold nanocolloid aqueous dispersion for food or drink according to Item 1 or 2, wherein the gold content is 0.1 to 1.0% by weight.
Item 4. Item 4. The gold nanocolloid aqueous solution for food and drink according to any one of Items 1 to 3, wherein the gold particles are gold particles obtained by reducing a gold compound with at least one reducing agent selected from the group consisting of an alcohol and an organic acid. Dispersion.
Item 5. Item 5. The gold nanocolloid aqueous dispersion for food and drink according to Item 4, wherein the gold compound is at least one selected from the group consisting of gold chloride, chloroauric acid, and a salt of chloroauric acid.
Item 6. Item 6. The gold nanocolloid aqueous dispersion for food or drink according to any one of Items 1 to 5, wherein the particle size of the gold particles is 5 to 50 nm.
Item 7. Item 5. The gold nanocolloid for food and beverage according to item 4, wherein the reducing agent is at least one selected from the group consisting of ethanol, acetic acid, propionic acid, butyric acid, lactic acid, tartaric acid, malic acid, succinic acid, sorbic acid and benzoic acid. Aqueous dispersion.
Item 8. Item 8. The gold nanocolloid aqueous dispersion for food or drink according to Items 1 to 7, wherein the pH is 5 to 11.
Item 9. Mixing at least one reducing agent selected from the group consisting of gold compounds, alcohols and organic acids, and at least one protective agent selected from the group consisting of gelatin, collagen and collagen peptides A method for producing a gold nanocolloid aqueous dispersion.

  In general, as the concentration of gold particles in the solution increases, the gold particles that precipitate become larger and agglomerate and precipitate as black or brown gold particles. Therefore, the gold particles are used as a red colorant by plasmon absorption. It is not possible. However, the aqueous colloidal gold dispersion of the present invention uses a specific reducing agent and a specific protective agent, so that the gold particles do not aggregate in the aqueous solution even when the concentration of the gold particles is high, and is stable. Disperse uniformly. Therefore, according to the present invention, a gold nanocolloid aqueous dispersion (stock solution) having a high concentration, that is, a dark color and stable for a long period of time can be obtained.

  Furthermore, since the gold nanocolloid aqueous dispersion of the present invention has a high concentration of gold particles dispersed in an aqueous solution, it is possible to color the food or drink only by adding a small amount of the gold colloid aqueous dispersion to the food or drink. it can. Moreover, since the addition amount to food / beverage products can be made small, the taste and food texture of food / beverage products are not impaired.

Gold Nanocolloid Aqueous Dispersion The gold nanocolloid aqueous dispersion of the present invention is a gold nanocolloid aqueous dispersion containing gold particles and a protective agent. Gold particles are obtained by reducing a gold compound with a reducing agent.

  As the gold compound, for example, gold chloride, chloroauric acid, a salt of chloroauric acid, or the like may be used. Examples of the salt of chloroauric acid include sodium chloroaurate and potassium chloroaurate. These gold compounds may be used alone or in combination of two or more.

  The gold concentration in the gold nanocolloid aqueous dispersion (final composition) of the present invention is, for example, about 0.1 to 1.0% by weight (about 5 to 50 mmol / l), preferably about 0.1% by weight. More than about 0.6% by weight (over 5 mmol / l to about 30 mmol / l), more preferably over 0.1% by weight to about 0.4% by weight (over 5 mmol / l to 20 mmol / l) l or less), more preferably about 0.12 to 0.4% by weight or less (about 6 to 20 mmol / l).

  What is necessary is just to select the usage-amount of a gold compound suitably so that the density | concentration of the gold | metal in gold nano colloid aqueous dispersion (final composition) may become the said density | concentration range.

  The particle size of the gold particles in the gold nanocolloid aqueous dispersion is usually about 5 to 50 nm, preferably about 5 to 30 nm, more preferably about 5 to 25 nm. The particle diameter of the gold particles in the gold nanocolloid aqueous dispersion is measured by the method described in the Examples section described later.

  The reducing agent for reducing the gold compound is not particularly limited as long as it can reduce the gold compound and can be used for food and drink. For example, alcohol such as ethanol; acetic acid, propionic acid, butyric acid, lactic acid, tartaric acid, malic acid And organic acids such as succinic acid, sorbic acid and benzoic acid. Among these, acetic acid, propionic acid, butyric acid, lactic acid, malic acid and tartaric acid are preferable.

  These reducing agents may be used individually by 1 type, and may be used in mixture of 2 or more types.

  According to the reducing agent of the present invention, the reaction between the gold compound and the reducing agent does not proceed abruptly and progresses gently, so that the gold particles produced by the reduction are uniformly dispersed in the solution without agglomeration.

  For example, when a reducing agent having a strong reducing power, such as sodium borohydride, citrate, or ascorbate, is used, the gold compound is rapidly reduced when the gold compound and the reducing agent are mixed, and gold particles are contained in the solution. Cannot easily obtain an aqueous dispersion (colorant) containing gold at a high concentration (for example, more than 0.1% by weight).

  The amount of the reducing agent used is usually about 0.25 to 100 mol times, preferably about 0.5 to 20 mol times the gold concentration in the gold nanocolloid aqueous dispersion (final composition).

  Examples of the protective agent (dispersing agent) of the present invention include naturally occurring food polypeptides such as gelatin, collagen, collagen peptides, etc. Among these, collagen peptides are preferred.

  The molecular weight of the polypeptide is, for example, about 500 to 10,000, preferably about 1,000 to 5,000. These polypeptides are not particularly limited as long as they can be used for food. For example, those obtained from animals such as fish, birds and mammals may be used.

  The amount of the protective agent used is usually about 0.1 to 10% by weight, preferably about 0.1 to 8.0% by weight, based on the total amount of the aqueous gold nanocolloid dispersion (final composition) of the present invention. More preferably, it is about 0.2 to 6.0% by weight.

  In the present invention, by using the above-mentioned protective agent, the gold particles can be stably and uniformly dispersed for a long time in the gold nanocolloid aqueous dispersion.

  The gold nanocolloid aqueous dispersion of the present invention contains the above gold particles, a reducing agent, a protective agent and water.

  Although the water used by this invention is not specifically limited, For example, deionized water, distilled water, etc. should just be used, Preferably the water sterilized by boiling etc. is used.

  What is necessary is just to adjust the usage-amount of water suitably according to the target gold | metal concentration and the required amount of each component.

  In this invention, you may mix | blend various additives used for a general food additive as needed further.

  Typical examples of such additives include pH adjusters, preservatives, antioxidants, acidulants, fragrances, emulsifiers, thickeners, and other pigments.

  Examples of the pH adjuster include strong alkali salts of weak acids such as sodium carbonate, potassium carbonate, and sodium citrate. Among these, sodium carbonate is preferable.

  What is necessary is just to adjust the usage-amount of a pH adjuster suitably so that gold nanocolloid aqueous dispersion may become the target pH.

  The pH of the gold nanocolloid aqueous dispersion of the present invention is usually about 5 to 11, preferably about 6 to 9.

  The gold nanocolloid aqueous dispersion liquid of the present invention in which a gold compound, a reducing agent, a protective agent and, if necessary, an additive are mixed in water so as to have the above predetermined amount is used as a colorant for food and drink as a stock solution. .

  The color of the gold nanocolloid aqueous dispersion (final composition, ie, stock solution) of the present invention varies depending on the concentration of gold, the type and concentration of each component, and usually has a deep red color.

Production Method In the production method of the aqueous gold nanocolloid dispersion of the present invention, the gold compound, the reducing agent, the protective agent, and the additive added as necessary are mixed with water, and the gold compound and the reducing agent are reacted. Thus, an aqueous solution in which gold particles are uniformly dispersed in a colloidal form is obtained.

  In the production method of the present invention, in order to promote the reaction between the gold compound and the reducing agent, the mixed solution of each component may be heated, stirred, or the like as necessary.

  The mixing temperature of each component may be appropriately selected according to the reducing power of the reducing agent, etc., but is usually from room temperature (about 5 ° C. to 40 ° C.) to the boiling point of water (100 ° C.), preferably 50 under normal pressure. What is necessary is just to set it as the range of about the boiling point (100 degreeC) of water. Further, the mixed solution may be stirred while heating under reflux.

  The reaction time of the gold compound and the reducing agent is usually about 5 minutes to 6 hours, preferably about 15 minutes to 3 hours, and more preferably about 30 minutes to 1.5 hours.

  The order of adding these components is not particularly limited, and any order of addition may be used.

  In the production method of the present invention, a gold compound is reduced by a reducing agent in an aqueous solution to form a colloidal solution of zero-valent gold nanoparticles. As described above, according to the reducing agent of the present invention, the reaction between the gold compound and the reducing agent proceeds mildly without proceeding abruptly. In the aqueous solution, the gold particles are uniformly dispersed without agglomeration.

  Furthermore, in the present invention, by using the protective agent (dispersing agent), even when the gold concentration in the gold nanocolloid aqueous dispersion is increased, the gold nanoparticles are stably dispersed in the aqueous solution. .

Food and drink gold compound, the reducing agent, protective agent, gold nano colloidal aqueous dispersion of an additive as needed invention was blended so that the predetermined amount of water is water soluble and stock it As a colorant for food and drink.

  Such a stock solution may be used as it is, or may be further diluted with water. When diluting such a stock solution with water, it is generally diluted by a volume ratio of about 1 to 20 times, preferably about 1 to 5 times, and used in an appropriate composition according to the purpose of use.

  The gold nanocolloid aqueous dispersion of the present invention is useful as a coloring agent for food and drink, particularly for drinking.

  Examples of foods and drinks that can be colored with the gold nanocolloid aqueous dispersion of the present invention include a wide range of foods and drinks, and examples thereof include soft drinks, alcoholic beverages, ice creams, soft creams, Japanese confectionery, and jelly foods.

  When the gold nanocolloid aqueous dispersion of the present invention is added to a food / beverage product that is almost colorless and transparent or a food / beverage product that is close to white, it can be colored red, wine, pink, etc., depending on the amount added.

  Hereinafter, the present invention will be further clarified by giving examples and comparative examples of the gold nanocolloid aqueous dispersion of the present invention, but the present invention is not limited thereto. In the following, “%” means “% by weight”.

Example 1
20 ml of a solution of 2.05 ml of 243 mM chloroauric acid aqueous solution and 120 g of collagen peptide (Ikuos HDL-50F, molecular weight 5000, manufactured by Nitta Gelatin Co., Ltd.) in 1 L of deionized water, and 0.03 ml of ethanol (gold concentration and equimolar) The mixture is diluted to about double volume with deionized water (DIW), adjusted to pH 8.0 with 5.3 ml of a 1.0 M sodium carbonate aqueous solution, and deionized water is added thereto to make a total volume of 100 ml. It was.

  The obtained mixed solution was transferred to a reaction flask equipped with a condenser and reacted for 2 hours while refluxing at the boiling point to obtain a uniform dark red-purple gold nanocolloid aqueous dispersion (5 mM concentration). The obtained gold nanocolloid aqueous dispersion contains 0.1% by weight of gold.

  When the gold nanocolloid aqueous dispersion was photographed with a transmission electron microscope (JEM-2000EX manufactured by JEOL Ltd.), the gold particles had a diameter of about 5 to 30 nm.

  Further, when 5% of the obtained gold nanocolloid aqueous dispersion (stock solution) was added to commercially available sake, it showed a beautiful wine color.

Example 2
2.05 ml of 243 mM chloroauric acid aqueous solution, 20 ml of a collagen peptide (Ikuos HDL-50F, molecular weight 5000, Nitta Gelatin Co., Ltd.) 120 g dissolved in 1 L of deionized water, and 0.45 g of lactic acid (10 times the gold concentration) Molar amount) was mixed and dissolved, and diluted with deionized water (DIW) to make a total amount of 100 ml.

  The obtained mixed liquid was transferred to a reaction flask equipped with a condenser and reacted for 2 hours while refluxing at the boiling point to obtain a uniform dark red-purple gold nanocolloid aqueous dispersion (concentration of 5 mM). The obtained gold nanocolloid aqueous dispersion contains 0.1% by weight of gold.

  When the gold nanocolloid aqueous dispersion was photographed with a transmission electron microscope, the gold particles had a diameter of about 5 to 25 nm.

  Further, when 0.5% of the obtained gold nanocolloid aqueous dispersion (stock solution) was added to commercially available alkaline ionized water, it showed a beautiful light pink color.

Example 3
60 ml of a solution obtained by dissolving 8.198 ml of 243 mM chloroauric acid aqueous solution, 120 g of marine collagen oligo CF (molecular weight 1000 manufactured by Chisso Corporation) in 1 L of deionized water, and 0.6 g of tartaric acid (2 times the molar amount of gold concentration) The mixture was mixed and diluted with 20 ml of deionized water (DIW). The pH was adjusted to 8.0 with 9.4 ml of a 1.0 M aqueous solution of sodium carbonate, and deionized water was added to make the total volume 100 ml.

  The obtained mixed solution was transferred to a reaction flask equipped with a condenser, and reacted for 2 hours while refluxing at the boiling point to obtain a homogeneous dark red-purple gold colloidal solution (gold concentration 20 mM). The obtained gold nanocolloid aqueous dispersion contains 0.4% by weight of gold.

  When the gold nanocolloid aqueous dispersion was photographed with a transmission electron microscope, the gold particles had a particle diameter of about 10 to 30 nm.

  Moreover, when 0.5% of the obtained gold nanocolloid aqueous dispersion (stock solution) was added to commercially available sake, a beautiful wine color was exhibited.

Example 4
20 ml of a solution prepared by dissolving 2.06 ml of a 486 mM chloroauric acid aqueous solution and 120 g of Iquos HDL-50F (molecular weight 5000, manufactured by Nitta Gelatin Co., Ltd.) in 1 L of deionized water, and 2.0 ml of an acetic acid 500 mM aqueous solution (equal molar amount of gold concentration) Of acetic acid), diluted with 20 ml of deionized water (DIW), adjusted to pH 7.0 with 5.3 ml of a 1.0 M aqueous solution of sodium carbonate, and added with deionized water to make a total volume of 100 ml. It was.

  The resulting mixed liquid was transferred to a reaction flask equipped with a condenser and reacted for 2 hours while refluxing at the boiling point to obtain a uniform dark red-purple gold colloid liquid (gold concentration 10 mM). The obtained gold nanocolloid aqueous dispersion contains 0.2% by weight of gold.

  When the gold nanocolloid aqueous dispersion was photographed with a transmission electron microscope, the gold particles had a particle diameter of about 10 to 30 nm.

  Further, when the obtained gold nanocolloid aqueous dispersion (stock solution) was added to 1.0% of commercially available sake, it showed a beautiful wine color.

Comparative Example 1
2.05 ml of 243 mM chloroauric acid aqueous solution and 0.03 ml of ethanol (gold concentration and equimolar amount) were mixed, diluted to about double volume with deionized water (DIW), and then 5.3 ml of 1.0 M sodium carbonate aqueous solution was added. In addition, the pH was adjusted to 8.0, and deionized water was added to make the total volume 100 ml.

  The resulting mixed liquid was transferred to a reaction flask equipped with a condenser and reacted for 2 hours while refluxing at the boiling point. It was. When the precipitate was observed with a stereomicroscope (carton zoom binocular stereomicroscope NSZ-70PFL), the particle size of gold was about several tens to 100 μm. The obtained liquid contains 0.1% by weight of gold.

Comparative Example 2
Dissolve 2.05 ml of 243 mM chloroauric acid aqueous solution and 0.45 g of lactic acid (10-fold molar amount of gold concentration), dilute to about double volume with deionized water (DIW), add deionized water to it. The total volume was 100 ml.

  The resulting mixed liquid was transferred to a reaction flask equipped with a condenser and reacted for 2 hours while refluxing at the boiling point. The supernatant liquid was only colorless and transparent, and a precipitate of gold-colored coarse gold particles was obtained. It was. When the precipitate was observed with a stereomicroscope, the particle size of gold was about several tens to 100 μm. The obtained liquid contains 0.1% by weight of gold.

Comparative Example 3
8.198 ml of 243 mM chloroauric acid aqueous solution and 0.6 g of tartaric acid (2 times molar amount of gold concentration) were mixed, diluted to about double amount with deionized water (DIW), and then 9.5 ml of 1.0 M aqueous sodium carbonate solution. The pH was adjusted to 8.0 and deionized water was added to make the total volume 100 ml.

  The resulting mixed liquid was transferred to a reaction flask equipped with a condenser and reacted for 2 hours while refluxing at the boiling point. It was. When the precipitate was observed with a stereomicroscope, the particle size of gold was several tens to 100 microns. The obtained liquid contains 0.4% by weight of gold.

Comparative Example 4
205.9 mg of chloroauric acid tetrahydrate was dissolved in 68.88 g of ion-exchanged water, 25 g of ethanol, 20 mol of polyoxyethylene and 0.1 g of sorbitan monolaurate were added, and the mixture was heated to reflux for 1 hour at the boiling point. At this time, gold was deposited on and adhered to the inner wall of the flask, but was not deposited in the liquid. A solution obtained by dissolving 811 mg of potassium citrate monohydrate in 5 g of water was added dropwise thereto, and the mixture was heated to reflux with stirring for 10 minutes. At this time, the reaction solution turned black as soon as the potassium citrate solution was added dropwise. After 10 minutes, black giant particles precipitated, and the supernatant was almost colorless and transparent. The obtained liquid contains 0.4% by weight of gold.

Claims (9)

A gold nanocolloid aqueous dispersion for food and drink comprising gold particles and at least one protective agent selected from the group consisting of gelatin, collagen and collagen peptides. The gold nanocolloid aqueous dispersion for food and drink according to claim 1, wherein the protective agent is a collagen peptide having a molecular weight of 500 to 10,000. The gold nanocolloid aqueous dispersion for food and drink according to claim 1 or 2, wherein the gold content is 0.1 to 1.0% by weight. The gold nanocolloid for food and drink according to any one of claims 1 to 3, wherein the gold particles are gold particles obtained by reducing a gold compound with at least one reducing agent selected from the group consisting of alcohol and organic acid. Aqueous dispersion. The gold nanocolloid aqueous dispersion for food and drink according to claim 4, wherein the gold compound is at least one selected from the group consisting of gold chloride, chloroauric acid and a salt of chloroauric acid. The gold nanocolloid aqueous dispersion for food and drink according to any one of claims 1 to 5, wherein the particle diameter of the gold particles is 5 to 50 nm. The gold nanoparticle for food and drink according to claim 4, wherein the reducing agent is at least one selected from the group consisting of ethanol, acetic acid, propionic acid, butyric acid, lactic acid, tartaric acid, malic acid, succinic acid, sorbic acid and benzoic acid. Colloidal aqueous dispersion. pH is 5-11, The gold | metal nanocolloid aqueous dispersion for food-drinks of Claims 1-7. Mixing at least one reducing agent selected from the group consisting of gold compounds, alcohols and organic acids, and at least one protective agent selected from the group consisting of gelatin, collagen and collagen peptides A method for producing a gold nanocolloid aqueous dispersion.