JPH04258260A - Polysaccharide gel and its production - Google Patents

Abstract

PURPOSE:To provide the subject gel having a high elastic modulus and excellent transparency and useful as a food raw material, etc., by mixing a prescribed amount of a multivalent metal salt with a prescribed amount of a polysaccharide capable of being gelled by the action of the ions of the multivalent metal, and subsequently subjecting the mixture to a high pressure treatment to form the gel. CONSTITUTION:A prescribed amount of a multivalent metal salt such as a Ca or Al salt is mixed with a prescribed amount of a polysaccharide such as polyuronide, alginic acid or acidic heteroglucan, capable of being gelled by the action of the ions of the multivalent metal, and the mixture is subjected to a high pressure treatment under a pressure of >=100MPa to substantially cause a gelling reaction for forming the objective gel.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention applies high-pressure processing technology and relates to a polysaccharide gel that gels under the action of polyvalent metal ions and a method for producing the same. This technology can be used in technical fields such as food, medicine, and immobilization carriers that use gels.

0002

[Prior Art] Gels have been used in various forms,
In addition to being used as a food material, it is also used as a shape-retaining material, an adhesive, a capsule or its wrapping material, and a carrier for immobilizing oxygen and microorganisms. As gels are widely used in this way, the required functions differ depending on the purpose, such as heat resistance, cold resistance, transparency, water retention, shape retention, elasticity, organoleptic suitability, salt resistance, and acid resistance. From these viewpoints, appropriate gel materials and preparation methods are adopted as appropriate.

Known raw materials used as gel materials include protein-based materials such as gelatin and albumin, polysaccharide-based materials such as glucan-based materials such as starch, galactan-based materials such as agar and gum arabic, and polyuronic acid-based materials such as pectin and alginic acid. They have different gelation mechanisms, gel properties, etc. For example, soluble type (agar, etc.), hydrophobic bond type (albumin, etc.), hydrogen bond type (high methoxy pectin, etc.),
These include ionic bond types (alginic acid, etc.).

Among these, the ionic bond type gels due to contact between the gel material and ions and does not require heat treatment, so it can be used to prepare various capsules through liquid-liquid reactions, and as a gel material that incorporates components that are easily denatured by heat. used.

[0005] A typical example of such an ion-binding type gel is a polyvalent metal ion cross-linked type gel, and for example, the following preparation method is known for alginate gel.

■Method of dropping a sodium alginate aqueous solution into a calcium salt aqueous solution (Japanese Patent Laid-Open No. 47-25375
or Special Publication No. 48-31907).

■Method of dropping a calcium salt aqueous solution into a sodium alginate aqueous solution (Japanese Patent Publication No. 48-16183)
).

[0008] After adding gluconodetal lactone (GDL) and calcium citrate etc. to a sodium alginate aqueous solution and raising the temperature, GDL decomposes and the pH increases, dissociating calcium citrate etc. and forming a calcium alginate gel. Method of forming (Special Publication No. 60-27520)
.

Similar techniques can be applied not only to alginate gels but also to other polyvalent metal ion crosslinked gels.

0010

[Problems to be Solved by the Invention] However, the above methods (1) and (2) are limited to capsule-shaped gels. This is because the reaction between alginic acid and calcium is fast and it is difficult to mold it into any desired shape. In (2), this point can be slightly improved, but since the essential reaction principle is the same, there are restrictions from the storage container surface, and the gel may become non-uniform depending on the shape. Furthermore, in all of (1) to (2), it is difficult to prepare a gel with a high elastic modulus because a solution is once prepared and then reacted to form a gel, which requires time and effort, and there is a limit to the concentration of the solution.

In view of the above-mentioned state of the art regarding polyvalent metal ion crosslinked gels such as alginate gels, the present invention has been developed to enable molding into any desired shape through extremely simplified steps and to adjust gel strength over a wide range. The present invention provides a technology for producing other saccharide gels that is capable of

0012

[Means for Solving the Problems] The present invention is a polysaccharide gel that is forcibly gelled by high-pressure treatment, and a gel composition containing this gel as the main skeleton of the gel. be. Furthermore, the present invention provides a polysaccharide which includes a step of mixing a predetermined amount of a polysaccharide and a polyvalent metal salt that can be gelled by the action of a polyvalent metal ion, and treating the mixture under high pressure to cause a substantial gelation reaction to form a gel. This is a method for producing saccharide gel.

According to the present invention, it is not necessary to separately prepare a polysaccharide solution and a polyvalent metal ion solution and cause a liquid-liquid reaction, and the entire gelation process can be performed in a single line, resulting in a significant reduction in process steps. Simplification can be achieved. Furthermore,
There are no restrictions on the shape of the resulting gel based on the liquid-liquid reaction, and it is basically possible to have any shape, and it is also possible to adjust the gel strength within a wide range.

The reason for such effects is not clear, but when polysaccharides and polyvalent metal salts are treated at high pressure in the presence of water, hydration reactions and ion dissociation occur, respectively, and both occur simultaneously. This is thought to be due to the fact that the cross-linking reaction due to ionic bonding can be forced to occur. Therefore, high concentrations that could not be predicted using conventional technology,
For example, gelation is possible even in the presence of water sufficient for hydration.

According to the present invention, a polysaccharide gel that can be used in a wide range of technical fields can be easily provided. That is, the polysaccharide gel of the present invention has a high elastic modulus, excellent transparency, and can contain other ingredients, so it can be used as a food material, a packaging material for pharmaceuticals, and even reactive substances. It can be widely used as a support for.

The present invention will be explained in detail below.

First, the polysaccharide gel of the present invention is characterized in that it is forcibly gelled by high pressure treatment. "High-pressure treatment" refers to treatment whose purpose is to apply pressure to an object to be treated. Therefore, incidental heating and other physical effects, such as application of shearing forces, are permissible as long as this is not the intended purpose. Also, “high pressure”
This refers to a pressure sufficient to cause a desired reaction, and although it is not uniquely defined, in the present invention it is usually a pressure of 100 MPa or more. The high pressure treatment will be described later.

[0018] "Forcibly gelled by high-pressure treatment" means that gelation is caused directly by high-pressure treatment and gelation does not occur unless high-pressure treatment is performed. Therefore, the present invention does not include liquid-liquid reactions in the prior art, ie, cases where reaction occurs and gelation occurs simply by mixing, such as the reaction between an aqueous polysaccharide solution and an aqueous polyvalent metal salt solution. In other words, it refers to forcibly gelling a mixed system of polysaccharides and polyvalent metal salts, which do not gel as they are, by applying high pressure. However, as long as high-pressure treatment is a direct cause of gelation, it is not excluded that high-pressure treatment is performed as pre-treatment, post-treatment, etc. before and after gelation.

If high-pressure treatment is applied before gelation, then gelation can be promoted by adding polyvalent metal ions, and high-pressure treatment after gelation can increase gel strength or reshape the gel. It's already clear.

[0020] "Polysaccharide gel" refers to a polysaccharide gel whose main component is a polyvalent metal ion crosslinked gel. The polyvalent metal ion forms an ionic bond with a reactive group (for example, a carboxyl group) of the polysaccharide, thereby constructing a crosslinked structure. Therefore,
If the main component of the gel is crosslinked with polyvalent metal ions, it may contain a crosslinked structure formed by hydrogen bonding of polysaccharide molecules as a secondary component. This is because the gel structure of polysaccharide gel is complex and is rarely constructed by a single mechanism. Further, even if the gel contains other components, it is sufficient if the main component of the gel is a polyvalent metal ion gel.

[0021] The "polyvalent metal ion" is selected as appropriate depending on the intended gel, and includes, for example, calcium,
Refers to polyvalent metal ions such as aluminum, barium, copper, iron, zinc, strontium, and nickel. Gel strength etc. are affected by the type of polyvalent metal ion, and some gels may be practically difficult to use depending on their purpose, so this point should be taken into consideration. Calcium is a practical ion that easily forms ionic bonds. It is sufficient if these polyvalent metal ions are supplied in the form of a salt or an aqueous solution. The manufacturing method will be described later.

[0022] "Polysaccharide" refers to a polysaccharide capable of forming a polyvalent metal ion crosslinked gel. Therefore, it is necessary for the polyvalent metal ion to have a reactive group (crosslinking point) capable of ionically bonding. Examples of the reactive group include a carboxyl group, a sulfate group, and an amino group. Typical polysaccharides containing these in their molecules are acidic heteroglycans, and include vegetable polysaccharides such as alginic acid, pectin, cellulose derivatives, chitosan, xanthan gum, locust bean gum, curdlan, gellan gum, and tracanth gum. can. However, animal polysaccharides such as chondroitin may be used depending on the case. In addition, from the viewpoint of high-pressure treatment, it is preferable that the gel structure is not weakened under high pressure.In other words, under high pressure, the activity of polyvalent metal ions as crosslinking points is promoted, and water retention etc. etc. does not affect. Table 1 shows an example of changes in elastic modulus of gel due to high pressure (other than gelatin is acidic heteroglycan)
.

[0023]

[Table 1] Table 1 ──────────────────────
────── Sample
Elasticity x 10-5 [N/m2]
(concentration)
Untreated High pressure treated #
──────────────────────
────── Alginic acid (2%*)
1.68 3.10
Pectin (2%*)
1.24 2.06
Gellan gum (1%*)
0.391 0.399
κ-carrageenan (2%) 0.
498 0.432
Agar (2%)
0.247 0.271
Gelatin (10%) 0
．． 191 0.236
──────────────────────────
── *2%CaCl2
#400MPa, 30 seconds This table shows gelatinized gels (1 x 1 x 1
Gel elastic modulus when applying hydrostatic pressure of 400 MPa for 30 seconds to cm) (measured by Leona-RE3305 Yamaden Co., Ltd.)
This shows the changes in From this table, it can be seen that the gel concentration increases in some cases and decreases in others due to high pressure treatment.

From this, in principle, any polysaccharide that can be gelled with polyvalent metal ions can be used in the present invention, but from the viewpoint of improving gel strength, it is necessary to prevent the gel from becoming brittle due to high pressure treatment. Preferably. That is, even if a polysaccharide is gelled by high-pressure treatment, if the gel becomes brittle due to high pressure, it becomes difficult to prepare a gel with strength above a certain level, and the treatment time may not be sufficient for cross-linking reaction. sell. As is clear from Table 1, preferred heteroglycans are polyuronides rich in uronic acids such as alginic acid and pectin.

[0025] Polyuronide is rich in uronic acid and has carboxyl groups responsible for ionic bonding within the molecule. Examples of polyuronides include high methoxy pectin, low methoxy pectin, alginic acid and its derivatives, tracanth gum, and the like. In particular, low methoxy pectin and alginic acid, which have many carboxyl groups, are preferred. By using these, high-pressure treatment can be performed more effectively, and furthermore, it is also possible to perform high-pressure treatment again after gelation to stabilize the gel or to reform it into a desired shape. Therefore, it is sufficient that it falls within the general range.

[0026]Alginate gel has different properties depending on the ratio of mannuronic acid (M) and guluronic acid (G) that constitute it, so this should be taken into consideration. For example, M/G
When the ratio is about 0.2, salt resistance is achieved, but when the ratio is about 1.0, salt resistance is significantly reduced. Therefore, polysaccharides are appropriately selected depending on the intended use of the gel.

Next, the "polysaccharide gel" of the present invention will be explained.

[0028] This gel was forcibly gelled by high-pressure treatment. Therefore, the concentration of polysaccharide, etc. can be increased to a degree that could not be predicted using conventional techniques, and a gel with extremely high gel strength can be obtained. This is because the polysaccharide is forcibly hydrated by high-pressure treatment and at the same time polyvalent metal ions are dissociated, thereby causing a crosslinking reaction. Therefore, liquid-liquid reactions and the like in the prior art are not required at all. This is because there is only need to be enough water to hydrate the polysaccharide. Water used for purposes other than hydration, such as water as a solvent for dissolving polyvalent metal ions or water as a dispersion medium for forming a homogeneous dispersion system, is unnecessary.

Therefore, so-called powder mixing is possible. This is because in the present invention, the polysaccharide concentration can be increased except that water molecules and polyvalent metal ions are required to hydrate at least enough crosslinking points to construct a crosslinked structure sufficient to form a gel.

However, gel physical properties such as gel strength and gel transparency are essentially determined by the mutual relationship between the concentrations of polysaccharides, polyvalent metal ions, and water; therefore, for example, a gel with weak gel strength may be prepared. If so, an appropriate amount of water should be present as a solvent or dispersion medium. That is, the properties of the gel can be adjusted depending on the balance of the components. However, in addition to the ingredients, the pressure of high pressure treatment,
The gel properties change greatly depending on time.

When the amount of water present is insufficient, the properties change from a state in which gel formation is impossible to a plastic, brittle, and hard gel depending on the degree.

The specific relationship between the three components and gel properties depends on the type of polysaccharide used (structure and number of reactive groups that serve as crosslinking points, etc.)
, is determined individually depending on the type of polyvalent metal ion and the state of existence of water. For example, with alginic acid, the concentration of alginic acid required for gelation is about 0.4 to 4% by weight, and with low methoxy pectin, it is similarly about 1 to 10% by weight. In principle, the concentration of polyvalent metal ions is determined by the reactive groups possessed by polysaccharides; for example, when alginic acid is crosslinked with calcium ions, the concentration of polyvalent metal ions is
The theoretical equivalent concentration is one calcium ion for two (mannuronic acid or guluronic acid). It has one carboxyl group in one unit and two calcium ions.
This is because it is valuable. Therefore, the amount relationship is usually equivalent to 0.5 mol of calcium per 1 mol of alginic acid. In the case of low methoxy pectin, etc., it can be carried out based on the same principle. However, when polyvalent metal ions are supplied from salt, the dissociation rate does not necessarily reach 100% under high pressure, so this point is taken into consideration in practice.

[0033] If the polyvalent metal ion concentration is less than the optimum concentration, the gelation will be weak, whereas if it is higher than the optimum concentration, calcium etc. will precipitate and remain in the gel as white dots, making it difficult to form a homogeneous gel. However, when the water content of the gel is high, it is possible to increase the calcium concentration in the gel without precipitating calcium or the like. The higher the water content, the lower the gel strength.

An example of the relationship between polysaccharide and polyvalent metal ion concentrations (when water is used as a solvent or dispersion medium) and gel properties is shown below.

FIG. 1 shows the influence of alginic acid and calcium citrate concentrations on dynamic elastic modulus (vertical automatic viscoelasticity measuring device VEM-800D, Yokohama System Research Institute). The higher the concentration of alginic acid, the higher the elastic modulus, but when the calcium concentration is at a constant value, the elastic modulus peaks, and even if the concentration is increased thereafter, the elastic modulus does not increase and instead decreases, but overall the elastic modulus is It can be seen that adjustment is possible up to a range of about 5.8×105 dyn/cm2.

The reference photograph is a photograph showing the appearance of the gel of the present invention obtained at a concentration corresponding to that shown in FIG. It can be seen that the transparency of the gel depends on the calcium concentration, and when the calcium concentration is high, the gel tends to be plastic and brittle. Such transparency has been difficult to obtain with conventional techniques.

[0037] For example, in a gel using alginic acid, alginic acid 1 to 15%, calcium 0.5mM to 2mM
It has a gelatin-like appearance and texture within a range of degrees.

Since this gel is heat resistant, it has properties not seen in conventional gelatin and alginate gels.

Further, FIGS. 2 and 3 show comparative observations of the gel tissue structure of the present invention using a dialysis gel and an electron microscope. The dialysis method is a method in which a dialysis tube is sealed with a sodium alginate aqueous solution and immersed in a calcium chloride aqueous solution or the like to form a calcium alginate gel through the dialysis tube. The dialysis method contains 3% sodium alginate and 3% calcium chloride, while the method of the present invention (processed at 1000 MPa for 30 minutes) contains 1% sodium alginate and 1% calcium citrate, and both alginic acids have a M/G ratio. is 0.2. In the gel of the present invention, although the alginate concentration is only 1/3 of that in the dialysis method, the network is dense and a uniform structure can be observed. However, since the properties of the network naturally differ depending on the pressure level and processing time of the high-pressure treatment, the same network cannot be observed in all gels of the present invention, but the same tendency can be clearly recognized. . Note that the electron micrographs in FIGS. 2 and 3 were obtained by processing and observing samples using the Three's replica method.

Another feature of the gel of the present invention is its salt, which serves as a source of polyvalent metal ions. That is, in the present invention, since a gel is forcibly formed by high pressure treatment, the polyvalent metal salt does not necessarily need to be soluble. In conventional methods based on liquid-liquid reactions and dialysis methods, the polyvalent metal ions must first be dissociated before the gelation reaction, so the salt used as a premise is water-soluble. For example, the solubility of calcium citrate is 0.1%
Therefore, it is difficult to increase the calcium concentration any further using this method, and therefore, the polysaccharide concentration cannot be increased beyond a certain level, and the range in which the elasticity of the gel can be adjusted is limited. On the other hand, in the present invention, since dissociation of polyvalent metal ions is promoted by high-pressure treatment, it is possible to use a salt that is sparingly water-soluble.

In this respect, the gel of the present invention is significantly different from conventional gels, and this can be verified by analyzing the anionic compounds present in the gel.

[0042] Next, the method for producing the above polysaccharide gel will be explained.

The method of the present invention basically involves mixing a predetermined amount of a polysaccharide and a polyvalent metal salt that can be gelled by the action of polyvalent metal ions, and treating the mixture at high pressure in the presence of water to cause a substantial gelation reaction. This is a method for producing a polysaccharide gel, which includes a step of generating a polysaccharide gel to form a gel.

[0044] The term "polysaccharide that can be gelled by the action of polyvalent metal ions" herein has the same meaning as the polysaccharide described above. "Polyvalent metal salt" refers to a salt that can be a source of the aforementioned polyvalent metal ions, such as citric acid, lactic acid, gluconic acid,
Examples include organic acid salts such as malic acid, and inorganic compounds such as chlorides and phosphates. Taking calcium as an example, preferred examples include calcium citrate, calcium hydrogen phosphate, calcium lactate, calcium gluconate, and calcium chloride. These metal ions (
This is because it dissociates calcium). Calcium citrate and calcium hydrogen phosphate are generally poorly water soluble, but dissociate metal ions under high pressure. Calcium lactate and calcium gluconate are easily solubilized by heating.
Although they are generally classified as soluble, their dissolution rate is low.

When a polyvalent metal salt with low water solubility is used, it is convenient to handle because the gelation reaction does not proceed before high pressure treatment even if an aqueous dispersion system is used for mixing with polysaccharides. Therefore, it is possible to mix sufficiently and uniformly with the polysaccharide before high-pressure treatment. Here, "low water solubility"
This means that the solubility is low when it is made into an aqueous dispersion system before high-pressure treatment. Therefore, the solubility of the metal salt may be suppressed by the temperature, pH value, etc. of the aqueous dispersion system.

[0046] Furthermore, the gel properties vary depending on the type of polyvalent metal ion used, and further vary depending on the type of salt. For example, when calcium citrate is used in alginic acid, a highly elastic gel is obtained, and when calcium chloride is used, a hard gel is obtained.

[0047] In addition, foods containing various salts are used from the viewpoint of promoting the dissociation of metal ions during high-pressure treatment and suppressing the dissociation in the previous stage, and from the viewpoint of increasing the value of the gel itself as a food. Ingredients, such as powdered milk, cheese,
Any product can be used as long as it has a relatively high salt content, such as concentrated milk or spices, and by adding it, the necessary polyvalent metal ions can be finally supplied. Included in metal salts.

Next, "mixing a predetermined amount" of a polysaccharide and a polyvalent metal salt means that they are prepared based on the relationship as described above.

[0049] "Mixing and high-pressure treatment in the presence of water" means that a mixed system containing water is formed at least during high-pressure treatment. As long as the dissociation of polyvalent metal ions and the hydration of polysaccharides can proceed simultaneously under high pressure, a uniform water dispersion may be prepared in advance, or one may be dispersed in water and then the other added and further mixed. You may. However, from the viewpoint of suppressing the gelation reaction before high-pressure treatment, it is preferable to disperse the powder in water after mixing the powder. According to powder mixing, it is possible to add components at this stage that either do not have a substantial adverse effect on gelation, or may intentionally have some effect on gelation. For example, trace elements such as iron and copper for nutritional enrichment. The addition of other components is not limited to powder mixing, and may be dissolved and dispersed in a dispersion medium in advance.

Gelatin, etc. may be added as a gelling agent, sugars, amino acids, etc. as taste components, phosphates, citrates, etc. as pH adjusters, flavoring agents, coloring agents, etc. may be added as desired. However, these added weights are not included in the polysaccharide concentration calculation. These mixed systems include various aqueous solutions,
It includes emulsions and suspensions, and for example, milk and the like can be used. As mentioned above, the moisture content of the material to be treated during high-pressure treatment is sufficient to hydrate the polysaccharide, and is determined individually depending on the type of polysaccharide. For example, in the case of sodium alginate, the concentration is 20% or less. The moisture content is such that the concentration is 10% or less for low methoxy pectin. However, since polyvalent metal ions are also contained, this amount should also be taken into consideration, and if the salt has hydration water, this should also be taken into consideration. There are no particular restrictions on the temperature, pH, etc. of water as a dispersion medium. Temperature and pH may be adjusted in relation to the solubility of the polyvalent metal salt.

The mixed system dispersed in water can have various properties depending on the desired gel, from a slurry to a dough having plastic shape retention properties, depending on the amount of water added. Therefore, if it is dough-shaped, it can be molded into a desired shape at this stage. It has been impossible to mold the material into a desired shape using conventional techniques. Furthermore, if the slurry is stored in a tube or the like of a desired shape, it can be molded in the same manner.

Mixing means, dispersion means, etc. may be carried out based on known techniques.The time from dispersion in water to high pressure treatment is as follows:
It usually takes several minutes to several hours. If it is too long, a gelation reaction may start, and if it is too short, the polysaccharide may not be sufficiently hydrated, but if it is too short, this can be adjusted by adjusting the high-pressure treatment time. It doesn't have to take any time at all.

[0053] Next, "high-pressure treatment" means applying sufficient pressure to the object to be treated to gel it. As long as the pressure is applied, the pressure distribution and time change are not particularly limited, but it is preferable that the pressure is less affected by other physical effects such as shearing force and polishing force. This is to form an elastic and uniform gel. Therefore, it is preferable to prepare a homogeneous dispersion of polysaccharides in advance, and statically promote the hydration of the polysaccharides during high-pressure treatment, and at the same time promote the dissociation of polyvalent metal ions. In addition, the effect that air bubbles in the treated object are removed during high-pressure treatment is also observed, making it easier to form a gel that is less likely to become cloudy.

Although it varies depending on the type of polysaccharide, the processing pressure is generally preferably 100 MPa or more, more preferably 400 MPa or more. At a pressure lower than 100 MPa, forced hydration of polysaccharides and forced dissociation of polyvalent metal ions are not sufficiently promoted at the same time, making it difficult to form a crosslinked structure and resulting in a gel that tends to be cloudy and contains bubbles. It becomes easier. Generally, the higher the treatment pressure, the better the crosslinking reaction will be promoted, and at 400 MPa or higher, a highly elastic and extremely strong gel can be obtained over a wide range of polysaccharide concentrations. The specific means for carrying out the high-pressure treatment may be any shape or method as long as it can achieve high pressure; for example, it may be carried out using a cold isostatic pressurization device.

[0055] In high-pressure treatment using the above-mentioned apparatus, pressure is applied almost uniformly to the object to be treated, and treatment using hydrostatic pressure, which is basically static treatment, is preferable from the viewpoint of gel formation. This is because shearing force and the like are not applied to the object to be processed more than necessary. However, gel strength increases with high pressure, and gels that have binding ability can be molded by applying high pressure treatment again after gelation, even if not under hydrostatic pressure.

On the other hand, the high-pressure treatment time also affects gelation. It usually takes about several seconds to 30 minutes, and may be carried out until the desired gel is formed. Here, the processing time refers to the time during which the pressure is maintained after reaching a predetermined pressure. For products whose gel strength is reduced by high-pressure treatment, long-term treatment may cause the gel to become brittle, but for other products, gel strength is maintained even after long-term treatment without any problem. Specific examples of these gels include those illustrated in Table 1 above. If the strength increases under high pressure, the gel strength may be adjusted by adjusting the time appropriately even after gelation. If the treatment time is short, gelation will not proceed sufficiently.

[0057] Next, "the gelation reaction is substantially caused by the high pressure treatment" means that the gelation reaction may have started to some extent before the high pressure treatment, but it does not mean that the gelation reaction does not reach the point where a gel is formed before the high pressure treatment. This refers to the formation of a gel by the action of pressure during high-pressure treatment without causing such a reaction. Therefore, if an aqueous dispersion system is prepared before high-pressure treatment, some polyvalent metal salts may start a gelation reaction, but this is acceptable.

[0058] "Containing a step" means that operations other than high-pressure treatment may be performed before or after high-pressure treatment, such as heat treatment, emulsification treatment, reformation treatment, etc., in order to obtain a gelled product. means.

Regarding re-molding, after forming the gel, put it into a molding container of any shape (an ordinary high-pressure container may be used) and pressurize it preferably to 100 MPa or more, so that it can be molded according to the molding mold. Furthermore, it is also possible to mix or laminate multiple types of gels, process them under high pressure, and re-shape them.

As explained above, the polysaccharide gel of the present invention exhibits functions that cannot be obtained with conventional polysaccharide gels, and by using this as the main skeleton of the gel, various gel-like compositions can be constructed. Can be done. Here, "using polysaccharide gel as the main skeleton of the gel" means that it can be used together with gels made of other components, and as long as the polysaccharide gel of the present invention is contained as the main component of the gel, other components can be used without limitation. It means that it can contain, and
Any dispersion medium other than gel can be used. Furthermore, even if the emulsion does not appear to be a gel, the gel of the present invention can be incorporated into a W/O or O/W type emulsion to stabilize it and prevent syneresis.

[0061] Also, the term "gel-like composition" refers to, for example, gels with various viscoelastic properties in the food field, so gel foods with new textures, calcium-enriched foods, trace elements (Ca, Fe, Cu), etc. , Zr)-containing gel, salt-resistant gel that maintains its shape without collapsing even in salt or soy sauce, and enteric gel that does not dissolve in acid but dissolves in alkaline. As a specific example of enteric gel, high calcium-containing alginate gel can be mentioned as a dietary food. Calcium alginate separates into alginic acid and calcium in the stomach, and calcium is absorbed in the intestines.

[0062] In the pharmaceutical field, the gel of the present invention is also heat resistant, so it is suitable for use as a gel material that incorporates pharmaceuticals that are easily denatured by heat.

In the field of immobilization carriers, it is suitable for gels that immobilize oxygen and microorganisms. This product can withstand long-term continuous operation.

[0064]

[Example] Example 1. Mix 1 g of sodium alginate (350G, Kibun Food Chemifa Co., Ltd.) and 1 g of calcium citrate (Shika 1 grade, Kanto Kagaku Co., Ltd.) into powder, then add 98 g of water, disperse well, make a slurry, and then bag it in a plastic bag. I put it in. The appearance is a heterogeneous system in which white particles of calcium citrate are uniformly dispersed. The slurry placed in the plastic bag was pressurized for 5 minutes at 100 MPa, 200 MPa, 300 MPa, and 400 MPa using a Mitsubishi cold isostatic pressure device (MCT150, Mitsubishi Heavy Industries, Ltd.), respectively. Both were able to form a gel, but the pressure was 100 MPa, 2
At 00 MPa, some undissolved calcium citrate remained in the gel as white spots. On the other hand, the pressure is 300MPa
At 400 MPa, it became a uniform, transparent gel with moderate elasticity. This gel was immersed in a 10% saline solution to examine salt resistance. As a result, the gel did not collapse even after 3 days of immersion, and salt resistance was observed. Example 2. Mix 1 g of sodium alginate (350G, Kibun Food Chemifa Co., Ltd.) and 1.13 g of calcium gluconate monohydrate (Wako special grade, Wako Pure Chemical Industries, Ltd.) into powder, then add 6 g of water and disperse well. It was made into a slurry and then placed in a plastic bag. The appearance is a heterogeneous system in which white particles of calcium gluconate are uniformly dispersed. This slurry was processed using a Mitsubishi cold isostatic pressure device (MCT150, Mitsubishi Heavy Industries, Ltd.).
) for 15 minutes at 990 MPa. After pressurizing,
The slurry became a transparent, uniform gel with moderate elasticity. This gel was immersed in a 10% saline solution to examine salt resistance. As a result, the gel did not collapse even after 3 days of immersion, and salt resistance was observed. Example 3. Mix 1 g of sodium alginate (350G, Kibun Food Chemifa Co., Ltd.) and 0.8 g of DL-calcium lactate pentahydrate (Wako Grade 1, Wako Pure Chemical Industries, Ltd.) into powder, then add 6 g of water and disperse well. It was made into a slurry and then placed in a plastic bag. The appearance is a heterogeneous system in which white particles of calcium lactate are uniformly dispersed. This slurry was pressurized at 990 MPa for 15 minutes using a Mitsubishi cold isostatic pressurizer (MCT150, Mitsubishi Heavy Industries, Ltd.). After pressurization, the slurry became a hard gel with minute white dots dispersed therein. This gel was immersed in a 10% saline solution to examine salt resistance. As a result, the gel did not collapse even after 3 days of immersion, and salt resistance was observed. Example 4. Mix 1 g of sodium alginate (350G, Kibun Food Chemifa Co., Ltd.) and 0.3 g of calcium chloride dihydrate (Wako special grade, Wako Pure Chemical Industries, Ltd.) into powder, then add 6 g of water to disperse well to form a slurry. Then I put it in a plastic bag. The appearance is a heterogeneous system in which white particles of calcium lactate are uniformly dispersed. This slurry was heated to 990M using a Mitsubishi cold isostatic pressurizer (MCT150, Mitsubishi Heavy Industries, Ltd.).
Pressure was applied at Pa for 15 minutes. After pressurization, the slurry turned into a very hard gel that was uniformly cloudy. This gel was immersed in a 10% saline solution to examine its salt resistance. As a result, the gel did not collapse even after 3 days of immersion, indicating salt resistance. Example 5. Low methoxyl pectin (Red3g, Snow Brand Foods Co., Ltd.)
1g and calcium citrate (Deer Grade 1, Kanto Kagaku Co., Ltd.)
After mixing 0.2 g of powder, 18.8 g of water was added to disperse it well to form a slurry, which was then placed in a plastic bag. This slurry was pressurized at 700 MPa for 30 minutes using a Mitsubishi cold isostatic presser (MCT150, Mitsubishi Heavy Industries, Ltd.). After pressurization, the slurry became a uniform gel. Example 6. Low methoxy pectin (LMSN325, Snow Brand Foods Co., Ltd.)
) 2g and calcium citrate (Deer Grade 1, Kanto Kagaku Co., Ltd.)
) 0.4 g was mixed into powder, 17.6 g of water was added, and the slurry was well dispersed, and the slurry was placed in a plastic bag. This slurry was applied to a Mitsubishi cold isostatic pressurizer (MCT150,
Pressure was applied at 700 MPa for 30 minutes using Mitsubishi Heavy Industries, Ltd. After pressurization, the slurry became a uniform hard gel.

[0065]

[Effects of the Invention] As explained above, polyvalent metal ion gels of polysaccharides that are forcibly gelled by high-pressure treatment cannot be produced using commonly used gel preparation methods such as dialysis because of the manufacturing method of high-pressure treatment. Not only can highly concentrated polysaccharide gels be prepared, but also gels with various elastic moduli can be prepared in one pass by changing the concentrations of polysaccharides and metal ions.

[0066] Furthermore, the gel can basically be molded into any shape, and the texture is gelatin-like.
Because it can contain trace elements such as calcium, various nutritional components, and medicinal components in high concentrations, it is extremely useful as a gel material in the fields of food, medicine, and immobilization alone.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the relationship between the dynamic elastic modulus of a calcium alginate gel according to the present invention and the concentrations of alginic acid and calcium citrate.

FIG. 2 is an electron micrograph in place of a drawing showing the shape of fibers of calcium alginate gel according to the present invention.

FIG. 3 is an electron micrograph in place of a drawing showing the shape of fibers of calcium alginate gel obtained by a conventional method (dialysis method).

Claims (6)

[Claims] 1. A polysaccharide gel that is forcibly gelled by high-pressure treatment. [Claim 2] Claim 1 wherein the polysaccharide is a polyuronide.
The polysaccharide gel described in . 3. A gel composition containing the polysaccharide gel according to claim 1 as a main skeleton of the gel. 4. A polysaccharide that includes a step of mixing a predetermined amount of a polysaccharide and a polyvalent metal salt that can be gelled by the action of polyvalent metal ions, and treating the mixture under high pressure to cause a substantial gelation reaction and form a gel. Method for producing saccharide gel. 5. The method for producing a polysaccharide gel according to claim 4, wherein the high-pressure treatment is carried out by pulverizing a predetermined amount of the polysaccharide and polyvalent metal salt and then dispersing the mixture in water. 6. The method for producing a polysaccharide gel according to claim 4, wherein the pressure of the high-pressure treatment is 100 MPa or more.