JP3179877B2 - Gelatin / neutral polysaccharide microcapsules and their production - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microcapsule formed of gelatin and a neutral polysaccharide which can contain a solid substance or a hydrophobic liquid, and a method for producing the microcapsule by a complex coacervation method for obtaining the same. Things.

[0002]

2. Description of the Related Art There is known a microencapsulation method in which a water-soluble polymer is used as a material for a capsule wall film, and a dense phase of the polymer is phase-separated around a core material to form a capsule wall film. . For example, after emulsifying a hydrophobic liquid with a water-soluble polymer such as gelatin, a non-solvent for the polymer such as ethanol or acetone is added, or an electrolyte salt such as sodium sulfate is added to form a simple coacervate. Or a mixture of a polycation colloid using gelatin or the like and a polyanion colloid using an anionic polysaccharide such as gum arabic, pectin, alginate or CMC.
The method for preparing microcapsules by the complex coacervation method of preparing H and causing phase separation is well known and has already been put to practical use.

[0003]

When microcapsules are used for food and drink, it is necessary to give priority to safety to the human body. For example, capsules obtained by a simple coacervation method are used to remove organic solvents or sodium sulfate. It is extremely difficult to completely remove the salts described above, which is not a practical method for producing capsules for food and drink.

In the case of the complex coacervation method,
Since it is generated only from the state of a dilute aqueous solution, there is a disadvantage that a large amount of energy is required for separating and removing water in the steps of separating, concentrating, and drying the formed capsule. Further, there is also a problem that unless the formed capsule wall film is insolubilized with, for example, formalin or the like, the capsules are aggregated or separated from each other.

Some proposals have been made to improve such disadvantages. For example, when preparing microcapsules by causing coacervation in a gelatin-anionic water-soluble polymer system, by adding a nonionic polymer substance to the system before cooling and gelling the coacervate, A method for preparing a microcapsule without a baby lumps (Japanese Patent Laid-Open No. 48-6657)
No. 9): Also, without hardening or completely hardening the microcapsules produced by the coacervation method, wheat flour, starch, powdered solid fat, celluloses, protein powder, inorganic salt powder, Powder of an organic acid or a salt thereof,
A method for producing a microcapsule which is coated with an amino acid or a salt thereof, a sucrose powder or the like and dried,
9-36540) and the like.

[0006] However, even in these improvement proposals, the coacervation process merely follows the conventional method, and no substantial improvement has been made. The present inventors have intensively studied a method for producing microcapsules for forming a complex coacervate from a high-concentration aqueous solution by improving the disadvantage of complex coacervation that is formed only in a dilute aqueous solution.

[0007]

As a result, an emulsion obtained by emulsifying or dispersing a water-insoluble solid or a hydrophobic liquid in an aqueous gelatin solution having a concentration of about 20% by weight or more is mixed with a neutral polysaccharide having a concentration of about 10% by weight or more. By adding the aqueous saccharide solution, rapid phase separation occurs, a complex coacervate is formed, and then gelatinization is performed by insolubilization after cooling gelation.
The present inventors have found that a microcapsule having a neutral polysaccharide as a wall film can be easily obtained, and completed the present invention.

Accordingly, an object of the present invention is to form a coacervate from a highly-concentrated solution of highly safe gelatin and a water-soluble neutral polysaccharide, and to omit complicated steps such as separation and washing, for example, to obtain a high-concentration coacervate. Efficiently using the dispersion as it is, or by subjecting it to spray drying, etc., and excellent in storage stability and release control of the contents,
In particular, it is an object of the present invention to provide a method for industrially extremely producing microcapsules suitable for food and drink applications.

[0009] The composite coacervation of the present invention comprises:
When the concentration of gelatin is at least about 5% by weight or more and the concentration of neutral polysaccharide is not at least about 15% by weight or more in a system in which a gelatin emulsion and a neutral polysaccharide solution are mixed, such a coacervate may be used. No formation is seen,
Alternatively, although the phenomenon of coacervation is observed, the phase separation is insufficient, and a strong coacervate cannot be obtained.

Since the mechanism of forming coacervate in the present invention is completely different from the conventional ionic reaction, any available gelatin can be used regardless of its preparation method and isoelectric point. Can be.

The neutral polysaccharides usable in the present invention include, for example, dextrin having a DE of about 2 to about 8, water-soluble modified starch, pullulan, and any mixture thereof. Can be. Coacervation as in the present invention does not occur even if low-molecular-weight sugars such as sucrose, glucose, D-sorbitol, or sugar alcohols are added instead of these water-soluble neutral polysaccharides.

Hereinafter, embodiments of the present invention will be described more specifically.

In the present invention, first, the concentration is about 20% by weight.
Using the above aqueous gelatin solution, an emulsion or dispersion of an oil-soluble substance such as an edible oil, a flavor oil, an oil-soluble vitamin-containing oil, or a fine powder of dried spices, or a fine powder of a dried animal or plant material is prepared. The mixing ratio of the oil-soluble substance or the fine powder to the aqueous solution of gelatin is generally in the range of about 0.1 to about 1 part by weight per 1 part by weight of the solution. You.

There are no special restrictions on the emulsification or dispersion treatment.
Any method can be adopted, but generally, a gelatin aqueous solution is stirred at a temperature as high as possible, for example, about 35 to about 45 ° C. or higher, which does not adversely affect the flavor oil and the like. After pouring and dispersing the oil-soluble substance or the fine powders, the mixture is emulsified or dispersed by using an arbitrary emulsifier such as a homomixer, a rotating disk homogenizer, and a high-pressure homogenizer. In a preferred embodiment, for example, the emulsification treatment is performed until the emulsified particles of the oil-soluble substance become about 0.5 to about 3 microns. It is preferable to use fine powder such as spices that have been finely pulverized to about 1 to about 3 microns.

By adding a neutral polysaccharide aqueous solution having a concentration of about 10 to about 30% by weight to the thus obtained emulsion or dispersion, rapid phase separation occurs to form a capsule. The amount of the neutral polysaccharide aqueous solution added to the gelatin emulsion is, for example, about 1.5 parts by weight per 1 part by weight of the former.
A range of about to about 3 parts by weight is often employed. The microcapsules thus formed have a particle size of about 5 to about 50 microns and are uniform particles having a substantially uniform spherical morphology. Next, the mixture is cooled to about 10 ° C. or lower while stirring, and gelatin is gelatinized to fix the film.

The above-mentioned microcapsules obtained by the present invention can be used as a capsule dispersion as it is or as a capsule powder after further spray drying and vacuum drying, but the strength of the capsule wall film is still sufficiently strong. I can't say. Therefore, it is usually preferable to further cure the film. The curing treatment of such a film can be carried out according to a conventional method without any particular limitation. In a preferred embodiment, for example, ethanol, tannic acid is added to the cooled, gelled capsule dispersion obtained as described above. And a curing agent usable for foods such as potash and the like are added to carry out a curing treatment of the film.

As an example of a specific method of using alum as a method of such a curing treatment, about 0.8 to about 3% by weight based on 1 part by weight of the gelled capsule dispersion liquid.
Alum aqueous solution of about 0.1 to about 1 part by weight, and further adjusted to a pH of about 5 to about 7 with sodium hydroxide, potassium hydroxide or the like, and stirred for about 15 minutes to about 1 hour, Microcapsules having practical film strength can be obtained. Hereinafter, embodiments of the present invention will be described more specifically with reference to examples.

[0018]

Example 1 220 g of a 20% (w / w%, hereinafter the same unless otherwise specified) gelatin aqueous solution heated to 40 ° C. was stirred with a TK-homomixer while stirring 22 g of lemon oil 22 g
Was added and emulsified at about 8000 rpm for about 10 minutes to prepare an emulsion having an emulsified particle diameter of about 1 to about 3 microns. Next, a 30% by weight aqueous solution of dextrin (DE2) was added to this emulsion.
5) 520 g was added to form a coacervation, and after stirring for about 10 minutes, the mixture was cooled to about 10 ° C. to gelatinize the gelatin and fix the capsule shell. To the obtained capsule dispersion, 380 g of a 3% aqueous solution of potassium alum was added, and the pH was adjusted to 7.0 with a 3N-NaOH aqueous solution.
Stirring was continued for 0 minutes to obtain a microcapsule dispersion having a reinforced film. This dispersion was spray-dried by a conventional method to obtain 200 g of the microcapsule powder of the present invention (Product 1 of the present invention).

[0019]

Comparative Example 1 300 g of gum arabic and 600 g of dextrin (DE2-5) were added to 1600 g of soft water and dissolved at 60 ° C. While stirring this solution using a homomixer, 100 g of lemon oil was added at about 40 ° C.
Emulsification was performed at 10 rpm for 10 minutes to obtain an emulsion having an emulsion particle size of 1 to 3 μm. This emulsion was spray-dried by a conventional method to obtain 950 g of dry powder (Comparative product 1).

The powders obtained in Example 1 and Comparative Example 1 were added to the chewing gum base in an amount of 1% each and kneaded, and plate gum was prepared by a conventional method. Sensory evaluation was performed. as a result,
The product 1 of the present invention has a somewhat modest top fragrance,
Elution of the lemon flavor lasted for several minutes at an average intensity, and was extremely highly evaluated. On the other hand, the comparative product 1 was evaluated as having a long elution of the lemon oil and felt the top flavor more strongly than necessary, but lost the flavor within about 1 minute, and was inferior in persistence and palatability.

[0021]

EXAMPLE 2 220 g of a 20% aqueous gelatin solution was heated to 40 ° C., and stirred with a homomixer while stirring paprika dye 22
g was added and emulsified at 8000 rpm for 10 minutes to prepare an emulsion having an emulsified particle diameter of 1 to 3 μm. Next, a 30% aqueous solution of dextrin (DE2-5) 52 was added to the emulsion.
0 g was added to form a coacervation, and the mixture was stirred for about 10 minutes and then cooled to 10 ° C. to gelatinize the gelatin and fix the capsule shell. 3% in the obtained capsule dispersion
380 g of a potassium alum aqueous solution is added, and 3N-N
The pH was adjusted to 7.0 with an aqueous aOH solution, and stirring was continued for 30 minutes to obtain a capsule dispersion having a reinforced film. This dispersion was spray-dried by a conventional method to obtain 200 g of the paprika pigment capsule powder of the present invention (Product 2 of the present invention).

[0022]

Comparative Example 2 300 g of modified starch (Oji National) and 60 g of dextrin (DE7-8) in 1300 g of soft water
Add 0 g, heat to 60 ° C, dissolve and cool to 40 ° C,
While stirring with a homomixer, 100 g of the same paprika dye as in Example 2 was added and emulsified at 8000 rpm for 10 minutes to prepare an emulsion having an emulsion particle size of about 1 to 5 microns.
This emulsion was spray-dried by a conventional method to obtain 940 g of paprika pigment powder (Comparative product 2).

Each of the paprika dye capsules or powders obtained in Example 2 and Comparative Example 2 was light-shielded and wrapped in a non-breathable packaging material and stored in a thermostat at 50 ° C. for 2 weeks to determine the change in color value. It was measured. Table 1 shows the results.

Color Value Measurement Method About 0.5 g of a paprika dye capsule or powder was precisely weighed and p
The solution was dissolved in a NaOH aqueous solution of about 9.0 H and the volume was adjusted to 100 ml. Take 5 ml of the solution, dilute in 50 ml of acetone, filter through a 0.4 μm non-aqueous Millipore filter,
The maximum absorbance ODmax (A) near 460 nm was measured, and the color value was calculated by the following equation.

[0025]

[Formula 1] Color value = A × 5000/5 × Sample amount (g)

[0026]

[Table 1]

As is clear from the results in Table 1, the product of the present invention 2
The paprika dye capsule has a remarkably dense and strong film as compared with the dye powder obtained by spray drying of the comparative product 2;
It was excellent in airtightness, and it was proved that the fading of the paprika dye could be effectively prevented.

[0028]

According to the present invention, a coacervate is formed from a highly safe solution of gelatin and a high-concentration solution of a water-soluble neutral polysaccharide, and is used without any complicated steps such as separation and washing. , A high-concentration microcapsule dispersion liquid can be obtained. Alternatively, microcapsules that are efficiently and excellent in storage stability and content release controllability by being subjected to spray drying and the like, and particularly suitable for use in foods and drinks, are industrially extremely advantageously provided.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-126016 (JP, A) JP-A-63-197540 (JP, A) JP-A-5-292899 (JP, A) JP-A 61-126899 78351 (JP, A) JP-A 1-299639 (JP, A) JP-A 61-4527 (JP, A) JP-A 63-223736 (JP, A) JP-A 64-25060 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) B01J 13/10 A23L 1/00 A23P 1/04 A23L 1/22

Claims (1)

(57) [Claims] 1. An aqueous solution of a water-soluble neutral polysaccharide having a concentration of about 10% by weight or more is added to an emulsion obtained by emulsifying or dispersing a water-insoluble solid or a hydrophobic liquid in an aqueous gelatin solution having a concentration of about 20% by weight or more. A method for producing gelatin / neutral polysaccharide microcapsules, which forms a complex coacervation.