JPH0728712B2 - Puffing and drying method for food etc. - Google Patents

Description

The present invention relates to a puffing and drying method for foods and the like having excellent puffability.

More specifically, the present invention relates to a method for puffing and drying a food or the like, which can impart an arbitrary puffing property to a dry food or the like.

Conventionally, there is a vacuum freezing method (hereinafter referred to as FD) as a method for obtaining a dried product of high quality such as food of biological origin. However
Since it is difficult to prevent the occurrence of glow discharge in FD, microwave microwave heating (hereinafter referred to as dielectric heating) cannot be industrially used. Therefore, for thick and thick objects, fruits and vegetables with high water content, etc. The range of use was limited due to the drawbacks such as low effect, extremely high cost, and inability to expand beyond the original shape.

In order to solve these drawbacks, the present inventors have previously proposed various methods by combining operations such as dielectric heating and depressurization, pressurization, freezing, and precipitation. It was difficult to give. (Japanese Patent Publication Sho 55-4878
8, 49822, JP-A-53-115847, 86050, 51-99174) The present inventor conducted research to obtain an excellent puffed dried food, and found an ideal method for producing a puffed dried food in the present invention. Could be established.

The present invention provides a tissue, composition or processed product of biological origin containing free water, which is placed in a gas pressurized atmosphere at a temperature that does not freeze, absorbs or permeates the gas, and then rapidly Freeze, let the gas in,
Then, the method is a puffing and drying method for foods and the like, which comprises reducing the pressure and then performing microwave dielectric heating under reduced pressure or normal pressure.

A first feature of the present invention is that the object to be processed is permeated with the gas in a gas pressurized atmosphere and is rapidly frozen to allow the gas to be contained in the object to be processed. By this treatment, the gas is contained in the object to be processed in a fine state with ice, and if it is frozen, the gas remains in the object to be processed even when the pressure is returned to normal pressure.

The second feature of the present invention is that the frozen object to be treated in which gas is contained is dielectrically heated under reduced pressure or normal pressure.
By this dielectric heating, frozen ice melts and escapes to the outside of the object to be treated in a very short time, but at the same time, the gas contained therein expands rapidly, hinders contraction due to dehydration and swells the object to be treated, and quickly The water is removed and evaporated to dryness.

The puffed dried product obtained here is expanded by 1 to 5 times and dried, and further, the water absorption restoration property is remarkably excellent.

In the present invention, the object to be treated is placed under a gas pressure atmosphere,
The subsequent quick freezing step can be done with any device, but here is shown one implementation device with the basic operations. FIG. 1 shows a vertical sectional view of the device. 1 is a high-pressure freezing container, which has a cylindrical shape with a squeezed lower part, and can be fixed and sealed to the upper part using a bolt and nut with an upper lid 2, and has a structure that can withstand a pressure of 120 kg / cm ² in the temperature range of −70 to 100 ° I'm running. The raw material to be processed is supplied into the high-pressure freezing container 1 from the charging port 4 under normal pressure by opening the bowl valve 3. The pressurizing gas is compressed and cooled by a vacuum pump and a refrigerator (not shown), press-fitted from the valve 5 and exhausted from the needle valve 6 for cycle use. The pressure is adjusted by a pressure gauge 9 connected by a cross joint 8 from a pipe 7 leading to the inside of the high-pressure freezing container 1 and a leak valve 10, and the operation is performed by switching the pressure from a signal from the pressure gauge 9. The controller activates the vacuum pump and cooler attached to the controller. The gas tanks connected to each other endure the same pressure as the pressure vessel. Reference numeral 12 is a jacket for covering the high-pressure freezing container.Refrigerant is supplied from the tank to the inside of the jacket 12 from the pipe 11 by a pump, discharged through the pipe 13, and cooled in a refrigerator by an attached temperature controller for cycle use. It is getting done. The internal temperature of the high-pressure freezing container 1 is captured by a thermocouple 14 inserted inside the container and displayed on a thermometer 15. The enclosed object and gas are stirred by a variable pitch type blade bar 17 penetrating the center of the inside of the high pressure freezing container by an electromagnetic stirrer 16 provided from above and outside the high pressure freezing container. As a result, the conduction of cold heat from the outer peripheral portion is promoted. The discharge of the object to be processed is carried out by opening the ball valve 20 of the discharge port 19 which is promoted by the screw 18 attached to the tip of the blade 17 after the pressure is released. Further, b and c can be attached and detached by blade rods of variable pitch.

In the present invention, a tissue body of biological origin, containing free water,
The composition and the processed product are all treated. The living thing includes all living things such as animals, plants, seaweeds, basidiomycetes, and microscopic organisms. As animals, various kinds of meat, fish and shellfish,
There are raw materials such as eggs, tissues such as fillets, compositions that leave tissues, processed products without tissues, and plants include fruits, vegetables, cereals, woody parts, flowers, roots, etc. There are as-is, tissues such as cut pieces, compositions that leave tissues, and processed products without tissues. In addition, examples of seaweed include tissues such as kelp, seaweed, and chlorella, compositions, and processed products. As basidiomycetes, there are shiitake mushrooms, enoki mushrooms and nameko. In addition, examples of microscopic organisms include baker's yeast, lactic acid bacteria, enzymes, noodle fungi, and natto bacteria.

It was difficult to obtain a puffed dried product excellent in moisture content such as vegetables and fruits even by any conventional drying treatment. It is possible to obtain goods.

Originally, the object to be treated of the present invention must contain at least free water, but when free water is lost or is insufficient, water is absorbed to absorb water, and if it is included as free water, degeneration of the tissue, Even if it is damaged, it will be treated.

The objects to be treated of the present invention include almost all foods, plants (flowers and trees for dried flowers, herbal medicine) animal and plant cells, powder processed products, colloids of various phases, and the like.

Since the free water shown in the present invention is of biological origin, it can be expressed in the following ranges.

Water in a sol or gel phase hydrated with a hydrophilic colloid material.

 Water that capillaries in the fine pores of the tissue.

 Water shown as the continuous phase above.

Water in a phase in which a hydrophilic substance and a poorly soluble substance are colloidally dispersed as emulsion.

These are the semi-permeable membranes of the cells, the water of the phase that is internally retained at various concentrations with osmotic pressure.

 It is water or the like of gelled products of these biocolloids.

These free waters are waters that can be defined as waters that can be frozen. Since the object to be treated containing free water is originally of biological origin, there is a difference between individual solids depending on the type, maturity level, and sampling period, and also depending on the site, and the swelling drying ratio may differ somewhat. Is.

The free water before the process can be accurately and easily obtained from the curve slope of the dielectric constant by measuring the dielectric constant with radio waves of different frequencies, and from the curve slope of the weight by heating the sample dielectrically. is there.

In addition, during the process, the infrared rays emitted by the sample during dielectric heating are measured through the pores provided in the cavity to measure the temperature, and free water is easily grasped by the change in the boiling point from the temperature gradient, which is linked to output adjustment, etc. Is something that can be done.

The object to be treated is placed in a gas pressurized atmosphere at a temperature at which it does not freeze. The gas absorbed by pressurization generally has a low solubility in water and a low diffusion rate in the gas phase outside the object to be treated, but the solubility in water is extremely high. For example, a gas having a high diffusion rate with respect to the outside gas phase, such as CO ₂ or NH _3, can be used. When using these, depending on the water content remaining in the product, it is necessary to pay attention to the effects such as stimulus and soft swelling effect on the taste and texture during eating. Also, it is difficult to put into practical use a gas that is addictive, flammable, and highly reactive, or an expensive gas. Gases that easily cause glow discharge in a low vacuum are also limited. Which gas is used depends on the effect and economy, but nitrogen gas and air are used because they are harmless and cheap, and methane, ethane, and Freon 13 are used depending on the effect. It is also bioinert, for example 21.38 mol N ₂ · 0.8
A mixed gas such as 93 mol CO ₂ is also practical. The higher the gas pressure and the lower the gas temperature, which does not freeze the object to be treated, tend to improve the finish expansion rate. However, a gas that liquefies at that pressure and temperature is not used.
The gas will be described below using N ₂ as an example.

The pressure of the gas may be any pressure, but a permeation effect also appears depending on the pressure, so 5 kg / cm ² or more is usually used. 12 kg / cm ² better effect is obtained, sufficiently good effect is obtained at 30 to 50 kg / cm ^2. At higher pressures, most objects will not have a particularly good effect. For biological cells, the pressure may be equal to or higher than the pressure obtained by subtracting the freezing pressure generated by freezing from the permeation pressure or swelling pressure of the boundary membrane.

The pressurization by the gas has to be maintained for a sufficient time for the gas to permeate into the object to be treated, although it depends on the degree of pressure and the temperature of the product. The pressurization of the gas is maintained for about 1 to 30 minutes, depending on the type of the object to be treated. Further, the lower the product temperature of the object to be treated, the higher the swelling rate, but it must be kept pressurized and cooled until the gas permeation is sufficiently achieved at the product temperature which does not freeze.

The pressure required for gas permeation varies depending on the individual or part of the object to be treated, if it has permeation pressure or swelling pressure through the boundary film. For example, the freezing temperature at N ₂ is -8 to -15 ° C. In the case of carrying out the method, the effect is obtained at a pressure 4 to 11 kg / cm ² lower than the permeation pressure. In the case of microorganisms, basidiomycetes, and algae, which have a relatively small difference in the osmotic pressure of solids or parts, the pressure may be 9 to 11 kg / cm ² lower than the osmotic pressure. Most of the gas permeation of vegetables and fruits is, for example, N ₂ at −0.5 to −7 ° C., 20 to 40 kg / cm 2.
^{A value of} about ² is sufficient.

If the pressure is increased to 45 kg / cm ² or more, it is not preferable that the tissue is torn due to excessive swelling when releasing the pressure after freezing and drying, but if the purpose is to easily fracture the tissue, Not so.

Since the object to be treated in the present invention is of biological origin and contains free water, it is almost all a colloidal sol or gel. Therefore, other substances and additives such as seasonings, buffers, and binders can be pressed in as colloids depending on the purpose. There is also a method of press-fitting in advance, but it is also possible to pressurize the gas and the solute or dispersoid into the cells at the same time by utilizing the gas pressurization. The pressure to be injected may be equal to or higher than the osmotic pressure or the swelling pressure of the plasma membrane of the living cell. Since the freezing pressure can be used in the present invention, the pressure obtained by subtracting the freezing pressure may be used. This total pressure is often 15-40 kg
/ cm ^2, which is within the range of pressure used in the present invention, and the object can be sufficiently achieved.

The object that has been sufficiently permeated under pressure is frozen while maintaining the pressure as it is. Cooling method is carried out from the back side of the cooling coil installed in the pressure vessel by agitating a fan to transfer cold heat to food through pressurized gas and by supplying a cold heat medium to the jacket outside the pressure vessel. And a method in which a harmless refrigerant is press-fitted into the pressure vessel to directly contact and cool the object to be treated. The former may not be suitable for brittle compositions such as fruits and vegetables when stirring under pressure to promote cooling, while the latter has a high gas loss and a high driving cost for press-fitting, but has a high freezing rate. Which method is used depends on the purpose. The carrier of cold energy has good heat transfer characteristics, is thermally stable, has good thermal properties such as a large heat capacity, and has good fluid properties and corrosion resistance, and is non-toxic and non-flammable. Is chosen from. Usually, chlorofluoromethane type Freon 12 and Freon 22 are used. Propanediol may be used in the jacket cooling system. Depending on the effect, polyhydric alcohols, fatty acids, liquid sugars, etc. can be used together at a temperature at which they do not freeze-crystallize.

When the gas dissolves in free water and permeates sufficiently, it must be rapidly frozen under pressure to allow the gas to be contained therein. Freezing is preferably performed by rapid freezing, and it is preferable to freeze immediately until the center temperature of the object to be treated reaches −15 ° C.

The action of quick freezing after absorbing or permeating gas such as N _{2 is} as long as it has a tissue such as raw beef,
By applying pressure and maintaining cooling above the freezing point, N ₂ is first absorbed by free water in the capillary bundle of raw meat, from which it diffuses into free water between muscle cells, permeates into cells, and and reached up to the solubility commensurate with temperature, sufficient N ₂ while maintaining the pressure and temperature until osmotic is absorbed, which upon rapid freezing to a temperature of -15 ° C. or less, N ₂ free water by connexion cells freezing pressure It can be explained that permeation from interstitial water into intracellular water occurs, and N ₂ is sufficiently spread inside the cells and is confined to ice, thereby completing freezing.

As for the freezing temperature, the central temperature of the object to be treated is required to be -15 ° C or lower, and the average temperature is preferably -18 ° C or lower. The average temperature may be from -28 ° C to -42 ° C, but many objects to be treated tend to be brittle and fragile. Most preferably, the average temperature is about -18 ° C to -27 ° C. In the case of meat storage and liver, after making coarse air bubbles and finishing, it is possible to stop the incomplete freezing at -5 to -15 ° C for the purpose of filling by replacing the high melting point seasoning fat or its emulsion with gas.

In the present invention, too slow freezing is not preferable because N ₂ collects in the center without being sequentially retained in the cell even if the temperature is low. The faster the freezing front advances, the more preferable the expanded body can be obtained. Therefore, rapid freezing is preferable. In the present invention, if necessary, the whole can be agitated to promote the conduction of cold heat and to be frozen rapidly.

Further, in a non-tissue-treated object such as yogurt, tofu, jelly, egg ware, fish paste, and pickled meat, N ₂ can be uniformly and freeze-fixed throughout the body by rapid freezing. If the total freezing is within 1 minute, 1-5 x 5 ice
N ₂ will be fixed and frozen in the form of 10 μ needles. If this is subjected to subsequent microwave dielectric heat treatment, the whole can be uniformly puffed and dried without causing any damage.

The freezing temperature of vegetables and fruits is preferably about -15 ° C to -20 ° C, and freezing at -30 ° C or higher is not preferable because it is fragile and easy to be used. Since these vegetables and fruits generally have little solute in the water content, stirring at the time of freezing is performed only at a slow freezing rate, and stirring is not usually required.

Due to rapid freezing below -15 ° C, the gas that permeated is frozen while it remains finely dispersed in the internal liquid containing free water of the object to be treated, and is internally fixed. It gives swelling. Center temperature of the object is -15 ℃
If it does not reach the above range, the gas may not be sufficiently contained due to the concentrated solute and the like, and when the pressure is released as it is, the gas may escape, which is not preferable. The time to reach -15 ° C or lower, that is, the speed of advance of the freezing front, determines the final position of the gas, the finished structure, and the expansion ratio. As described above, N ₂ is sufficiently permeated to the inside of cells and is frozen and fixed, and sufficient swelling can be obtained only by the microwave dielectric heating in the latter stage.

Pressurized, gas permeated, and rapidly frozen
The pressure is released, and microwave dielectric heating is performed under normal pressure or reduced pressure, but if the temperature is kept at -20 ° C or lower, the gas can be stored while holding the gas for a considerably long time. If the frozen object is left at normal pressure and room temperature, it will be about 60% in 1 hour after thawing.
Escape of N ₂ is the degree to which about 85% N ₂ at 2 hours from escaping.
Tissue-free colloidal sol rapidly loses N ₂ by thawing, but within 30 minutes after releasing pressure, most of N ₂ remains in the object to be treated and is fully swelled by dielectric heating. It is dried. In hot-air aeration drying or FD drying, the latent heat supply is carried forward, so that not only the effect higher than dielectric heating, which is internal heating, cannot be obtained, but also the gas easily escapes, which is rather inferior. The faster the pressure is released, the more the loss of gas is delayed due to the endothermic effect, and the expansion ratio does not differ much.

Pressurized, gas permeated, and rapidly frozen
Batch or continuous dielectric heat treatment is performed. At the time of treatment, it is under reduced pressure or normal pressure, and in the case of fresh meat storage, seafood, fruits, flowering trees, fine organisms, etc. having a maximum permissible temperature of about 52 ° C or less, preferably under reduced pressure of 4 to 70 torr, and Basidiomycetes, seaweeds, heated foods and the like, which can be treated at higher temperatures, are preferably under reduced pressure of atmospheric pressure to 70 torr.

In order to obtain the required effect, in some cases, it is submerged in a liquid containing no free water and having a low relative dielectric loss coefficient, such as fats and oils, fatty acids, polyhydric alcohols, liquid sugar, etc. It is also possible to perform dielectric heating under pressure. These liquids are a cooling medium to keep the object to be processed below freezing,
It is used for the purpose of, for example, substituting it with water or gas to fill the gap, or promoting the elution of some components. However, it should not be so large that the value of the relative dielectric loss coefficient is close to that of free water.

The microwave frequency is 2.
45 or 3 GHZ is preferable, and a thick one such as a polymer molding or wood is 915 MHZ or less. For microwave output, a device with a production efficiency of 50 to 200 kW / hr is preferable, but 1.3 or 4
It is better to use a multi-sphere magnetron of kW / hr. As a power feeding method, a klystron of 100 kW / hr may be applied through a single power feeding port, or a multi-sphere may be used to reduce the movement of charges, and a waveguide may be branched to feed power. If you can keep the sheet shape or stacked thickness below 30 mm,
The surface wave type dielectric heating, in which the electric field strength is largely concentrated and the dielectric efficiency is good, is used in view of equipment, operation cost, and heating speed. Conversely, the maximum depth from the surface to the center is 30 m /
If it exceeds m, it is possible to face each other alternately and supply power from multiple surfaces while preventing radio wave interference.
The shape of the inner surface of the cavity in the apparatus is preferably rectangular in order to prevent radio wave unevenness, but it is also cylindrical and can concentrate radio waves on an object to be processed that passes through the central portion.

The frequency of the microwave, the output, the power feeding method, and the shape of the inner wall surface of the cavity are appropriately changed depending on the type and state of the object to be treated, the treatment amount, the effect, and the like as shown in the above example. In addition, the microwave output is such that the degree of pressure reduction and the progress of drying-for example, after free water is lost, there is no escape area for heat, so the product temperature rises linearly even under reduced pressure. In order to supply enough radio waves to move to the evaporation surface and vaporize, the radio wave density per unit weight is gradually lowered, and the output can be gradually reduced. In short, it depends on how quickly the gas is expanded and dried while the gas is sufficiently contained therein, and various means can be used for that purpose. Dielectric heating is not only capable of uniform internal heating, but it is also possible to use free means according to the purpose in this way, but it is extremely limited in other FD and hot air drying because the freedom does not work. You can't get the effect. For example, thickness 10m / m
If the raw beef is frozen, the output is 50kW / h at a vacuum of 12 torr.
Dielectric heating is performed with the r device, and it is expanded and dried to a free magnification of about 1 to 2 times within 400 seconds, and automatic continuous production of tact feeding is possible, but with methods other than dielectric heating, it is effective over all of them. Can't get

In the puffing drying in the present invention, the melting of ice occurs by dielectric heating of microwaves, and at the same time, for example, in raw beef, first, the free molten water of the intermuscular capillaries suddenly ejects to form the dehydration holes. Then, the intracellular water is melted and vaporized.
The expansion of gas such as N ₂ explosively begins to expand while hindering the capillary contraction of the object to be processed, and sublimation, escape, and volatilization of free water occur while maintaining that state, and it spouts out of the object to be processed,
Immediately before it shrinks, it is swelled, fixed and dried.

Frozen products such as already-heated objects to be processed, 52 ° C
The object which may be heated as described above may be subjected to microwave dielectric heating under a reduced pressure of atmospheric pressure to 70 torr. This is a small sugar,
It is suitable for oils and fats, low protein contents and high water content, such as vegetables and flowering plants for dried flowers, basidiomycetes, seaweeds, processed egg products, rice cakes, rice, kamaboko and konjac. In this case, when removing free water and weak semi-bonded water, the radio wave density per unit weight is 1 kW /
0.1 to 1.5 kg is the most effective, and it is possible to obtain an excellent dried puffed product while preventing the loss of gas.

After free water is lost, desorption of water gradually becomes difficult. Therefore, if the gas dehumidified to a dew point of 0 to -63 ° C is forcedly circulated to lower the water vapor pressure on the surface, the power density will be lowered. A swollen and dried product can be quickly obtained.

In the present invention, since the object to be permeated with gas and frozen is subjected to microwave dielectric heating, the characteristics of ice such as high thermal conductivity of ice, freezing pressure and high permeability of microwave are maximized. The temperature of the product is always kept low because it can be used for a long time, it quickly becomes porous, the heat of moisture is dissipated well, and it becomes an irreversible swelling body before the gas that interferes with the contraction of the tissue can escape You can get a body.

Also, characteristics depending on the type of gas, gas pressure and pressurization time, properties of refrigerant, cooling method, pressure release time, thawing time, atmosphere during dielectric heating, condition of object to be processed, electric field strength, application method, treatment after completion It is possible to freely obtain an arbitrary expanded body in units of microns to centimeters by variously combining and adjusting the above.

Next, examples of the present invention will be described.

Example 1. Each of the objects to be treated shown in Table 1 was put into the pressure freezing apparatus shown in FIG. 1, N ₂ was fed at 4 ° C., and pressure was fed up to about 35 kg / cm ² , and 15 The temperature was maintained at 4 ° C. for 5 minutes while removing heat under the same pressure, and N ₂ was sufficiently permeated.

Then, a refrigerant CFC was introduced into the jacket to quickly cool the product temperature to -20 ° C. During that time, when the outside freezing began, gentle stirring was continued to encourage cooling. The cooling time was 10 minutes.

After 10 minutes from the introduction of the refrigerant, the pressurization is released, the frozen object is taken out, and immediately sent to the depressurization microwave induction heating device, the vacuum degree is set to 8 torr, the frequency is 2450 MHz, the effective radio wave output is 24.3 kW /
Approximately 6 for microwave dielectric heating at a rate of 15.3kg
The irreversible swelling peak of the water content of 3 to 8% by weight was reached in about 11 minutes, and this was taken out. The swelling rate of each treated product is shown in Table 1 below, and all treated products were excellent puffed dried products.

Example 2. Each of the objects to be treated shown in Table 2 was cut into pieces or put into the pressure freezing apparatus shown in FIG.
N ₂ was fed at each temperature shown in Table ₂ and fed under pressure up to about 30 kg / cm ² , and allowed to stand at the pressure as it was for each labeled time to sufficiently permeate N ₂ .

Then, a refrigerant was introduced into the jacket to quickly cool the product temperature to -30 ° C. In the meantime, for those that could be stirred, the stirring was continued gently to promote cooling. The cooling time was 4 minutes on average.

Four minutes after the introduction of the refrigerant, the frozen processed product was taken out and immediately fed into the atmospheric pressure microwave induction heating device that was blown with dry air, and the frequency was 2450MHz, effective radio wave output 24.3kW / processed product 15.3
Microwave dielectric heating at a rate of kg, about 5 minutes later, humidity 3%
The dehumidified dry air of (3) was forcedly recirculated, and the irreversible swelling peak with a water content of 5 to 10% by weight was reached in about 5 minutes thereafter, so the application was stopped and this was taken out.

The swelling rate of each treated material was 100 to 130%.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an example of an apparatus used for gas permeation and freezing in the method for expanding and drying food etc. according to the present invention. 1 ... High-pressure freezing container, 12 ... Jacket, 17 ... Variable pitch type blade bar

Claims (16)

[Claims] 1. A tissue derived from a living organism, containing free water, a composition, or a processed product, which is to be treated, is placed in a gas pressurized atmosphere at a temperature that does not freeze, and absorbs or permeates the gas. A method for swelling and drying a food or the like, which comprises subjecting the gas to internalizing, then rapidly freezing, reducing the pressure, and then subjecting the gas to microwave induction heating under reduced pressure or normal pressure. 2. A swelling of a food or the like according to claim 1, characterized in that the gas used is a gas that does not liquefy at a temperature of -60 ° C. or higher and a pressure of 80 kg / cm ² or less. Drying method. 3. The method for expanding and drying foods and the like according to claim 1, wherein the gas pressure is 12 kg / cm ² or more. 4. The gas pressurization is a gas pressure of minus 4 kg / cm ² or more, which is lower than the permeation pressure or swelling pressure of the boundary film of the object to be treated, according to claim 1. A method for expanding and drying foods and the like. 5. An object to be treated containing free water is a water content region near a minimum value of colloidal quasi-bonded water containing free water or a maximum value of quasi-bound water coexisting with free water. The object to be treated containing free water, the water content of which has been adjusted to a low level so as not to cause cohesive denaturation between substance components and welding between tissues, The method according to claim 1, Puffing and drying method for foods. 6. A method for swelling and drying foods or the like according to claim 1, characterized in that the gas is absorbed in extracellular free water and is permeated into the cells by freezing freezing pressure. . 7. The gas pressure is the osmotic pressure of the cell membrane of the tissue,
Alternatively, it is a pressurizing pressure equal to or higher than the swelling pressure, and the gas and solute or dispersoid are pressed into the cells by the pressure from the solution or dispersion liquid in which the object to be treated is immersed. A method for expanding and drying foods and the like according to claim 1. 8. A carrier for cold heat in rapid freezing is a liquid under normal pressure, or a gas that does not liquefy at a pressure of 12 to 80 kg / cm ^{2 at a} temperature of -15 to -60 ° C., and rapidly freezes in contact with an object to be treated. The method for expanding and drying foods or the like according to claim 1, characterized in that. 9. The method according to claim 1, wherein the microwave induction heating is performed under a reduced pressure of a vacuum degree of 70 torr or more adjusted to prevent the movement of charges. Puffing and drying method. 10. A microwave dielectric heating is performed under a reduced pressure of 70 torr or less or a normal pressure under a reduced pressure of 70 torr or less for an object having a maximum allowable temperature of 52 ° C. or more while free water is present in the object. The method for expanding and drying foods or the like according to claim 1, characterized by heating. 11. In microwave dielectric heating, an object to be treated is immersed or coated in a liquid having a low dielectric loss coefficient value, which is maintained or adjusted at a temperature below or above the freezing point, to be subjected to microwave dielectric heating. A method for expanding and drying foods and the like according to claim 1, which is characterized in that 12. In microwave dielectric heating, microwaves are applied as energy to push or move free moisture from the inside to the evaporation surface until the free moisture in the object to be processed is lost, and the evaporation is performed on the evaporation surface. The method for expanding and drying foods or the like according to claim 1, wherein latent heat is supplied by flowing gas or liquid. 13. In microwave induction heating, after the water content of the object to be dried loses free water and reaches the region of quasi-bonded water where the force for binding the water increases, a dew point of 0 is obtained.
Characterized by microwave induction heating by adjusting the radio wave energy density low so that the product temperature can be kept below the maximum allowable temperature required for the object to be processed under air or nitrogen gas supply of -60 ° C The method for expanding and drying foods and the like according to claim 1. 14. In microwave dielectric heating, when the maximum product thickness of the object being dried is maintained at 30 mm or less, surface wave type dielectric heating of a strong electric field is performed under low humidity ventilation. A method for expanding and drying foods and the like according to claim 1, which is characterized in that 15. In the microwave dielectric heating, when the maximum depth from the surface of the object to be processed to the inner central portion is 30 m / m or more, the object is sandwiched and the heating is performed alternately from the power supply ports alternately installed. The method for expanding and drying foods and the like according to claim 1, characterized in that. 16. A substance having innumerable bubbles and pores, or liquid to some or all of the bubbles and pores after the free water or quasi-bonded water is lost after the treatment according to claim 1. Alternatively, the method for expanding and drying foods and the like according to claim 1, wherein the substance is a substance in which the solid is replaced.