JPH05292899A - Production of microcapsule - Google Patents

Abstract

PURPOSE:To efficiently obtain the subject capsule causing no injury to human bodies, excellent in safety and edible property and useful for foods and medicines, etc., by using a transglutaminase as a coat curing agent in a complex coacervation method using a hydrophobic substance as a core substance, a protein and a polysaccharide. CONSTITUTION:The objective capsule is obtained by using a transglutaminase as a coat curing agent in a complex coacervation method using one kind or two or more kinds of hydrophobic substances selected from alpha-linolenic acid, eicosapentaenoic acid, docosahexaenoic acid, flavor and a vitamin and used as a core substance, a protein such as gelatin and a polysaccharide such as gum arabic.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing microcapsules in a complex coacervation method. More specifically, when curing the coacervate,
The present invention relates to a method for producing edible microcapsules obtained by using transglutaminase (hereinafter sometimes abbreviated as TG) in place of aldehydes that have been conventionally used as a curing agent.

[0002]

2. Description of the Related Art As a method for producing microcapsules containing a hydrophobic substance, a complex coacervation method described in, for example, US Pat. No. 2,800,457 is representative, and in most cases in practical use, a wall film forming substance is used. It is well known that the gelatin-arabic gum system is used as. This method involves emulsifying or dispersing a hydrophobic substance in an aqueous hydrophilic colloid solution having an electric charge (emulsification step), adding an aqueous hydrophilic colloid solution having an opposite electric charge to the above colloid, and diluting with water. After that, the step of adjusting the pH to cause coacervation to obtain a coacervate in which colloid is deposited around the hydrophobic substance that becomes the nucleus (core) (coacervation step), the step of cooling the coacervate to solidify ( Gelation step) and a step of insolubilizing the coacervate wall film (curing step). As a curing agent, aldehydes, diketones, epoxides, acid anhydrides and acid chlorides which are generally known as gelatin insolubilizers are used. In general, compounds such as inorganic salts are used. Among them, aldehydes are typically used from the viewpoint of effect, cost and supply. It has been.

[0003]

However, the method for producing microcapsules by the coacervation method is superior to the other encapsulation methods conventionally used for food production.
Although it has a merit that an extremely small particle size can be obtained, it is not suitable for food because a compound such as an aldehyde which is a reagent having a property unfavorable to the human body is used as a curing agent. Therefore, when trying to obtain edible microcapsules, aldehydes and other hardening agents cannot be used. It is well known that this hardening agent is an insolubilizing agent for gelatin, and that gum arabic is released after the capsule wall is formed. Therefore, an object of the present invention is to provide a method for producing edible microcapsules that does not harm the human body.

[0004]

As a result of intensive studies to solve the above problems, the present inventors have used transglutaminase (hereinafter abbreviated as TG) as a curing agent in place of compounds such as aldehydes. By doing so, they have found that edible microcapsules can be obtained by a safe and simple method, and have completed the present invention.

That is, the present invention is a method for producing microcapsules, characterized in that TG is used as a film hardening agent in a complex coacervation method comprising a protein having a hydrophobic substance as a core substance and a polysaccharide. Specifically, the hydrophobic substance and TG are dispersed in an aqueous solution at 20 to 80 ° C containing 1 to 10% of protein such as gelatin and 1 to 10% of polysaccharide such as gum arabic to adjust pH to the coacervation generation region. A microcapsule characterized by causing a coacervate layer to be produced by adjustment and then maintaining the condition at 20 to 80 ° C. to promote a crosslinking reaction by a protein such as gelatin and TG in the coacervate layer to cure the coacervate. Is a manufacturing method.

In the present invention, TG is added after the concentration of protein in the solution is made to a dilute state such that TG does not act.
After that, by causing coacervate to act and the coacervate layer having a high protein concentration to act on TG,
This protein can be crosslinked and polymerized by the acyl transfer reaction of the γ-carboxamide group of the glutamic acid residue in the protein forming the coacervate wall membrane. The TG can be added by dispersing it in a hydrophobic substance or by adding it to the surrounding aqueous solution. Thus, by using TG, the microcapsules can be obtained by curing the coacervate wall film without performing insolubilization treatment with a compound such as an aldehyde.

The TG used in the present invention may be any kind of TG regardless of its origin as long as it has TG activity. For example, Streptoverticillium (Stre
derived from microorganisms belonging to ptoverticillium (BT) (BT
Abbreviated as G. Incidentally, those derived from mammals such as JP-A-1-27471) and guinea pigs (abbreviated as MTG).
In addition, refer to Japanese Examined Patent Publication No. 1-50382), those derived from marine animals (see Nobuo Seki et al., 167 Abstracts of Autumn Meeting of the Fisheries Society of Japan and 219 Abstracts of Spring Meeting of the Fisheries Society of Japan in 1987), Obtained by genetic recombination using biotechnology (Japanese Patent Laid-Open No. 1-30
0889) and the like can be used. However, among them, it is preferable to use BTG, which is calcium-independent and can be obtained in a large amount.

The hydrophobic substance used in the present invention is not particularly limited. For example, vegetable oils such as corn oil, soybean oil, rapeseed oil, peanut oil and palm oil, animal oils such as fish oil, lard and head, and α-linolene. Examples thereof include fatty acids such as acids, eicosapentaenoic acid (abbreviated as EPA), and docosahexaenoic acid (abbreviated as DHA). Also, edible waxes may be used without any problem. These may be used alone or in combination and may be appropriately selected depending on the purpose. There is no problem in adding a flavor composition, an oil-soluble substance such as vitamins, a seasoning, a spice, an emulsifier, or a coloring agent to the oil or fat. In short, these may be blended individually or in plural according to the purpose. The flavor composition described here includes, for example, meat flavor, bonito flavour, and the like related to meat and seafood, fruit flavors, vegetable flavors, and the like. Examples of oil-soluble vitamins include vitamins A, D, E, F and K. You may mix these individually or in multiple numbers according to the objective. The amount of the hydrophobic substance used is not particularly limited, but it is 1 by weight with respect to the gelatin that normally forms a film.
It is about -10.

Although the above description has mainly dealt with hydrophobic materials, coacervates can incorporate water-soluble substances such as proteins, amino acids, nucleic acids, and enzymes into the interior, so that hydrophobic substances can be incorporated. At the same time, one kind or two or more kinds of substances selected from proteins, amino acids and nucleic acids can be used as the core substance. In the present invention in which the capsule wall is hardened by TG, the coacervate is encapsulated as it is, and therefore the above water-soluble substance can be sufficiently retained in the capsule. Also,
Hydrophobic substances and enzymes can also be used as core substances.
The microcapsules thus obtained can be used as an immobilized enzyme. That is, the present invention is also a method for producing an immobilized enzyme characterized by using a hydrophobic substance and an enzyme as core substances and transglutaminase as a film hardening agent in a complex coacervation method comprising a protein and a polysaccharide.

The protein used in the complex coacervation method of the present invention is not particularly limited as long as it is various acidic and basic edible proteins such as gelatin, casein, soybean protein and collagen. However, gelatin is most suitable because it is easy to use and has high encapsulation ability.

The polysaccharide used in the present invention is not particularly limited as long as it is various edible polysaccharides such as gum arabic, sodium arabinite and agar. However, commonly used gum arabic is most preferred in the present invention.

In the present invention, the weight ratio of the protein, the oil and fat, the emulsion comprising water, and the polysaccharide may be any ratio within the range where coacervation usually occurs. These weight ratios can be appropriately selected according to the purpose, and by controlling this, it is possible to produce microcapsules having the desired particle size. However, usually, a solution prepared by containing a protein such as gelatin in an amount of 1 to 10% and a polysaccharide such as gum arabic in an amount of 1 to 10% is used. A hydrophobic substance and TG are dispersed in this solution to adjust the pH in the coacervation generation region (protein to be used,
Although it depends on the type and combination of polysaccharides, when gelatin is used as the protein and gum arabic is used as the polysaccharide, the pH is usually 4
(Adjusted to −5.5) to generate a coacervate layer. Next, by keeping the condition of 20 to 80 ° C. for a certain period of time, the crosslinking reaction of the protein such as gelatin with TG in the coacervate layer proceeds to harden the coacervate to produce the desired microcapsules. By controlling the reaction time, it is possible to prepare microcapsules having desired characteristics, for example, sustained release. This is because the reaction temperature and the reaction time are factors that change the film strength.

The conditions for causing TG to act are TG
Can be appropriately selected as long as it exhibits catalytic activity and within a range where coacervation can occur. Usually, the temperature of the system is about 20-80 ° C, and the pH is about 4-8.
Within the range, the target acyl transfer reaction can be carried out unless a substance that significantly inhibits the enzyme activity is mixed. The amount of TG added is about 0.01 per 1 g of the protein present in the coacervate system.
.About.500 units (for this unit, JP-A-1-2747)
1) is desirable, and more preferably 0.1 to 100 units. The reason for this is that if the enzyme concentration is lower than this range, a sufficient reaction does not occur, and if it is higher than this range, it becomes difficult to control the reaction.

Further, in order to prevent aggregation and binding between the capsule particles in the step of curing the coating by acting TG, as disclosed in Japanese Patent Publication No. 47-16167,
It is also possible to add thickeners such as acacia tragacanth, methyl cellulose and carboxymethyl cellulose.

The microcapsules produced as described above can be used as they are after being dried by a usual drying means such as hot air drying and freeze drying, but they are further freeze dried and then pulverized into microcapsules. You may use a capsule. At this time, regarding the freeze-drying and crushing method,
Any conventional method may be used without any particular limitation.

[0016]

INDUSTRIAL APPLICABILITY The present invention uses a compound such as an aldehyde compound as a curing agent for a microcapsule film, and in the coacervation method, which has heretofore not been applicable to food production, TG is used instead of the curing agent. By utilizing, without impairing the merit of the coacervation method that capsules with a very small particle size can be obtained, it also has the function of holding not only oil-soluble substances but also water-soluble substances and foods. It is possible to provide a method for safely and simply obtaining edible microcapsules that can be used as a food.

It is also possible to control the release condition of the core substance in the capsule by adjusting the amount of TG added, the reaction temperature and the reaction time in the step of curing the capsule coating. That is, by adjusting the progress of the curing reaction, it is possible to form a coating film having various pressure resistance strengths, melting temperatures, and pore sizes. Therefore, according to this method,
It is also possible to produce perfume capsules with controlled sustained release, capsules that release only at the target temperature, and the like.

Further, as a result, the application is expanded not only to human consumption, but for example, as an initial feed for aquatic animals to be cultivated, for example, crustaceans such as prawns and black tiger, fishes such as yellowtail, eel and ayu. It is also very effective as a manufacturing method. That is, as a property required for the early-stage fishery feed, a water-soluble substance such as a growth-promoting factor had to be processed into a water-resistant material having a particle size capable of predating the larvae, which was conventionally impossible. This processing is also possible by this.

Recently, capsules of α-linolenic acid, EPA, and DHA, which are highly oxidizable and unstable as health foods, but also flavor compositions and substances such as vitamins, have a large particle size. However, there was no microencapsulated product. However, according to the present invention, substances such as EPA and DHA can be microencapsulated and stabilized. The present invention is also a curing agent in the complex coacervation method containing TG. The curing agent may contain TG in an amount of 0.1 to 100% by weight. Stabilizers such as mannitol other than TG may be added to the curing agent of the present invention.

[0020]

EXAMPLES The present invention will be described below based on examples.
The present invention is not limited to the examples.

Example 1 5 g of acid-treated gelatin manufactured by Nippi Co., Ltd. and 3 g of gum arabic manufactured by Sigma Co. were heated to 50 ° C.
20 g of BTG (obtained by the method of Example 1 of JP-A-1-27471) per 1 g of gelatin in the aqueous solution was added to 25 g of an aqueous solution dissolved in 300 g of warm water and corn salad oil manufactured by Ajinomoto Co., Inc. Emulsification was performed at 10,000 rpm / min for 5 minutes with an ace homogenizer manufactured by Nippon Seiki Co., Ltd. This emulsion was stirred in a 50 ° C water bath, pH was adjusted to 5 with 1N-NaOH to cause coacervation, and the mixture was reacted in a 50 ° C water bath for 120 minutes. After 60 minutes from the start of the reaction, stop stirring,
When left to stand, capsules of 50 to 60 μm were precipitated. Next, the capsule is taken out by decantation, and 50
When hot-air drying was performed at ℃, dissolution of the capsule and elution of oil were not observed, and a capsule powder containing oil was obtained. Also, when this was put into water at 25 ° C. and 80 ° C., no oil elution was observed in any case.
It should be noted that, instead of cone salad oil, EPA, DHA, α-
Similar results were obtained using linolenic acid and amino acid-containing fats and oils, respectively.

Example 2 Control of Release Temperature by Reaction Time In the same production method as in Example 1, capsules were produced with a reaction time of 60 minutes after coacervation occurred. Remove the capsules by decantation, 50
When hot air drying was performed at 0 ° C., dissolution of capsules and elution of oil were not observed, and a capsule powder containing oil was obtained as in Example 1. When this was poured into water at 25 ° C., oil leaching was not observed, but when it was poured into hot water at 80 ° C., leaching of oil was observed unlike Example 1. As can be seen from these results, by shortening the reaction time of TG, it was possible to manufacture microcapsules having sustained release properties at high temperature.

Example 3 Oxidative Stabilizing Effect Powdered microcapsules were produced using the same amount of sesame oil as the corn salad oil of Example 2. The obtained capsules were stored under normal temperature conditions, and their oxidative stability was examined. For comparison, a spray-dried product using dextrin as an adsorbent and a sesame oil powder clathrated with cyclodextrin were produced and subjected to a storage test under the same conditions. A sample was taken out every 7 days and the peroxide value was measured. The measuring method is that after extracting the oil from the powder with ether, JAS
The analysis was performed according to the measuring method by the method. The results are shown in Figure 1. The sesame oil pulverized by this method showed much higher oxidative stability than other methods. The POV in FIG. 1 indicates the peroxide value, and the higher the value, the more the oxidation is indicated. In addition, the same result was obtained in an experiment using EPA and DHA in fish oil.

Example 4 Stabilizing Effect of Flavors Microcapsules were produced by using the same amount of the oil and fat containing seafood flavor instead of the corn salad oil of Example 2. The obtained capsules were stored at 24 ° C., and changes in the deterioration degree of the encapsulated flavors were examined. For comparison tests as in Example 3, spray dried products using dextrin as an adsorbent and flavor powders clathrated with cyclodextrin were produced and subjected to a storage test under the same conditions. Degradation of flavor was determined by sensory evaluation by two-point comparison using flavor powder immediately after production as a control. As shown in the results of FIG. 2, the flavor powdered by this method showed extremely high stability as compared with the other methods.

(Example 5) Sustained release effect of flavor Microcapsules were produced using the same amount of aroma component (limonene) -containing fats and oils instead of the corn salad oil of Example 1. In the production, two types of capsules having reaction times after coacervation of 60 minutes (Sample 1) and 120 minutes (Sample 2) were prepared, and the release rate of the aroma component released from the capsules was measured. To measure the release rate, a petri dish in a desiccator is thinly filled with capsules, air is allowed to pass through at a constant rate, the aroma components volatilized in the passing air are collected by a cold trap, and the release rate is determined by the amount collected every predetermined time. I asked. As shown in the results in FIG. 3, the flavor powdered by this method could be controlled for sustained release by adjusting the reaction time after coacervation.

Example 6 Stabilizing Effect of Vitamin Microcapsules were produced by using the same amount of vitamin-containing fats and oils instead of the corn salad oil of Example 1. Using this capsule, the time course of the dissolution rate in water was compared with that of an uncoated vitamin. As shown in the results of FIG. 4, the vitamins encapsulated by this method were excellent in covering properties and were effective in preventing decomposition by heat and moisture.

Example 7 Stabilizing Effect of Nucleic Acid and Amino Acid Microcapsules were produced by using the same amount of the nucleic acid-containing fats and oils as the corn salad oil of Example 1. This was kneaded into ground fish meat having phosphatase that decomposes nucleic acid, and the stability during heating was examined. The nucleic acid residual rate was determined by measuring free phosphoric acid by enzymatic decomposition. The result is shown in Fig. 5.
As shown in, the nucleic acid encapsulated by this method was excellent in the protective effect against enzymatic degradation.

(Example 8) Immobilization of enzyme The TG added in the process of Example 1 was 100 units,
Microcapsules were produced. At this time, freeze drying was used instead of hot air drying for drying. After drying, the TG residual enzyme activity in the capsule was examined, and 90% residual activity was obtained.

[Brief description of drawings]

FIG. 1 shows the results of an oxidation promotion test of sesame oil.

FIG. 2 shows the results of flavor storage tests.

FIG. 3 shows the release behavior of aroma components.

FIG. 4 shows the results of vitamin elution test.

FIG. 5 shows the stability of nucleic acids.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical display location A23L 1/48 (72) Inventor Chito Kato 1-1 Suzuki-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa (72) Inventor, Takahiko Soeda 1-1, Suzuki-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Ajinomoto Co., Inc., Food-Research Institute

Claims (7)

[Claims] 1. A method for producing microcapsules, which comprises using transglutaminase as a film-hardening agent in a complex coacervation method comprising a protein having a hydrophobic substance as a core substance and a polysaccharide. 2. The method for producing microcapsules according to claim 1, wherein the protein is gelatin. 3. The method for producing microcapsules according to claim 1, wherein the polysaccharide is gum arabic. 4. The production of microcapsules according to claim 1, wherein the hydrophobic substance is one or more substances selected from α-linolenic acid, eicosapentaenoic acid, docosahexaenoic acid, flavors and vitamins. Method. 5. The method for producing microcapsules according to claim 1, wherein the core substance is one or more substances selected from proteins, amino acids and nucleic acids together with the hydrophobic substance. 6. A method for producing an immobilized enzyme, which comprises using a hydrophobic substance and an enzyme as a core substance and transglutaminase as a film hardening agent in a complex coacervation method comprising a protein and a polysaccharide. 7. A curing agent in a complex coacervation method containing transglutaminase.