JP6460556B1 - Method for producing frozen raw yuba - Google Patents

Abstract

Disclosed is a technique for producing frozen raw yuba, which can suppress a decrease in texture and flavor and discoloration of fresh yuba due to freezing and thawing.
The method for producing frozen raw yuba according to the present invention uses a soymilk preparation step of preparing a soymilk for storage by adding 31 to 50% by weight of sugar to raw soymilk, and a raw material soymilk to which no sugar is added. The frozen preparation step of storing the raw yuba produced in the above and the preservative soymilk in a freezing container, and the raw yuba and the preservative soymilk stored in the freezing container are -20 ° C to -80 ° C. The freezing step of cooling to the temperature range included in the range and freezing, and the raw yuba and the soy milk for storage in the frozen container in the frozen state at a temperature range included in the range of −18 ° C. to −80 ° C. And a frozen storage step for storing.
[Selection] Figure 5

Description

  The present invention relates to a freezing technique for raw hot-spring leaves such as pull-up hot-spring leaves and pump-up hot-spring leaves.

  Yuba, one of the processed soybean foods, is manufactured by heating soy milk and scooping up a film formed on the liquid surface with a thin rod-shaped device. Yuba has raw yuba and dried yuba. Raw yuba refers to the film scooped up from the liquid surface of soymilk, and dry yuba refers to the dried scooped film. Raw yuba is cooked as it is, and dry yuba is cooked after returning to water and softening.

  In addition, raw yuba is divided into those that are scooped after the film is completely formed on the liquid surface of soy milk, and those that are collected and scooped before the film is completely formed on the liquid surface of soy milk. Is called “pick-up yuba”, and the latter is called “kumiage yuba” (also called “knob yuba”). Unless otherwise specified, in this specification, both the raised yuba and kumeage yuba are collectively referred to as “raw yuba”.

  Compared to dry yuba, raw yuba is superior in texture and flavor and is used as an ingredient in various dishes. In addition, raw yuba can be eaten with a seasoning such as soy sauce as it is without cooking. However, unlike dry yuba, fresh yuba is susceptible to spoilage and cannot be stored for a long time.

  Then, what has been provided with a longer storage period by freezing raw yuba is provided, but the raw yuba thawed after frozen storage is inferior in texture and flavor to the raw yuba before freezing. This is because free yuba is frozen and the proteins contained in the yuba are denatured and aggregate, and once agglutinated protein is thawed, it does not return to its original state. Therefore, when the frozen raw yuba is thawed, the agglomerated protein hardens the raw yuba and reduces the texture and flavor.

JP 2001-057860

  In order to solve the above-mentioned problem, Patent Document 1 discloses a texture of frozen storage by adding a predetermined amount of sugar to soy milk that is a raw material for raw yuba or soy milk for immersing the raw yuba. And a method for producing frozen raw yuba with reduced deterioration in flavor. However, the raw yuba that has been frozen and stored by the method described in Patent Document 1 may turn brown in color during freezing or thawing, which has a problem in appearance.

  The problem to be solved by the present invention is to provide a technique for producing frozen raw yuba that can suppress a decrease in texture and flavor and discoloration of the raw yuba due to freezing and thawing.

In order to solve the above problems, a method for producing frozen raw yuba according to the present invention is as follows.
a) a soymilk preparation step of preparing a soymilk for storage by adding 31 to 50% by weight of sugar to the raw material soymilk;
b) A freezing preparation step of preparing a raw yuba manufactured using raw soymilk to which no saccharide is added, and a freezing container containing the preservative soymilk;
c) a freezing step in which the raw yuba and the soy milk for storage stored in the freezing container are cooled to a temperature range of −20 ° C. to −80 ° C. and frozen;
d) A freezing and storing step of storing the raw yuba and the soy milk for storage in the frozen container in a frozen state in a temperature range comprised between -18 ° C and -80 ° C.

  In the present invention, various kinds of sugars are contained in the soy milk for storage, and those having as little sweetness as possible are preferable. This is because the purpose of using the soy milk for storage containing saccharides in the present invention is to relieve the damage to the raw hot spring leaves by freezing or frozen storage. By using saccharides with less sweetness, the effect of the saccharides on the taste of fresh yuba can be reduced when the preservative soymilk containing the saccharide is frozen with fresh yuba and stored frozen. In addition, monosaccharides and disaccharides are preferable to polysaccharides in terms of excellent solubility in raw material soymilk, and more than one type of saccharides can be used. For example, trehalose, lactose, and maltose are known as sugars with low sweetness. These are all disaccharides. In the present invention, saccharides are added to the raw material soymilk to obtain a preservative soymilk. However, even when the raw material soymilk added with an amino acid (glycine) is used as the preservative soymilk, the same effects as the present invention are obtained. Is confirmed to be obtained.

  Moreover, in this invention, the manufacturing method of the raw material soymilk used for manufacture of the raw material soymilk and fresh yuba used at a soymilk preparation process is the same as the manufacturing method of a general soymilk. In other words, soy milk (raw material soymilk) is obtained by adding water and grinding to soybeans soaked in water to obtain raw kure, heating this noodle to obtain boiled koji, and then squeezing the boiled kew. can get.

In the soymilk preparation step, the raw material soymilk added with 31 to 50% by weight of saccharide is used, and the raw soymilk is used as it is (that is, without adding saccharides) for the production of raw yuba. .
In this case, it is preferable that the raw material soymilk used for the storage soymilk has a Brix value larger than that of the raw material soymilk used for the production of raw yuba, and in particular, the storage soymilk is a raw material soymilk having a Brix value of 7 to 9 degrees. It is recommended to use raw soymilk having a Brix value of 4 to 6 degrees for the production of raw yuba. The Brix value in soymilk refers to the concentration of soluble solids, and the larger the value, the more soluble solids are contained.

  The raw yuba is obtained by heating the raw soy milk in a kettle to 75 ° C. to 95 ° C., so that the protein is thermally coagulated, and the film formed on the liquid surface of the raw soy milk is scooped up with an elongated stick. When it is scooped up in a state where the film is completely formed on the liquid surface of the raw soymilk, it becomes a pulled-up yuba, and when it is scooped up before the film is completely formed, it becomes a pumped-up yuba. The more soluble solids contained in the raw soymilk used in the production of raw yuba, the faster it solidifies. Therefore, when producing the raised yuba, raise the Brix value of the raw soymilk slightly (for example, 5 to 6 degrees), When manufacturing, it is good to make the Brix value of raw material soy milk slightly low (for example, 4 to 5 degrees).

  The film scooped up from the kettle is stored in a container. This container may be the above-described freezing container or a container other than the freezing container. The raw material soymilk before becoming a film adheres to the film accommodated in the container. Since the temperature of the film and the raw material soy milk is high for a while after being contained in the container, the heat coagulation of the protein in the raw material soy milk proceeds. And the raw yuba is completed when the thermal coagulation of the protein is completed due to a decrease in temperature or the like. When the above operation is performed in a container different from the freezing container, the raw hot-spring leaves formed in the separate container are transferred to the freezing container. Then, the soy milk for preservation is added to the freezing container in which the raw yuba is accommodated. As described above, the freezing container in which the raw yuba and the soy milk for storage are accommodated is prepared.

  Moreover, you may add preservation | save soymilk in the middle of the thermal coagulation of protein in the container. Thereby, the progress of the thermal coagulation of the protein can be suppressed or stopped in the middle. Usually, when the preservative soymilk is at room temperature (around 15 ° C.), protein coagulation can be stopped. Therefore, raw yuba with different softness and viscosity can be obtained by changing the timing and amount of soy milk to be stored and the temperature of the soy milk to be stored. A part of the preservative soymilk added to the container as described above may be thermally coagulated, but most of the soymilk remains in the container in a liquid state. When the above operation is performed in a container different from the freezing container, the raw yuba and the soy milk for preservation formed in the separate container are transferred to the freezing container. As described above, the freezing container in which the raw yuba and the soy milk for storage are accommodated is prepared.

  The raw yuba and the preservative soymilk in the freezing container obtained as described above are cooled to a temperature range included in the range of −20 ° C. to −80 ° C. and frozen. In order to prevent evaporation and contamination of the soy milk for storage during freezing and later-described frozen storage, the freezing container is preferably closed with a lid or the like, more preferably sealed, and more preferably after deaeration. The Since the surface of the raw yuba in the container for freezing is covered with soy milk for storage, the raw yuba does not dry during freezing. Moreover, since the preservative soymilk contains a high concentration of 31 to 50% by weight of saccharides, the protein in the preservative soymilk during freezing is not only denatured and coagulated, but also denatured in the raw yuba. be able to. Furthermore, the color change of the raw yuba at the time of thawing | decompression can also be suppressed by denaturation | denaturation and coagulation | solidification of the protein in preservation | save soymilk.

  The raw yuba and the soy milk for storage in the freezing container frozen by the above method are stored in a temperature range included in the range of −18 ° C. to −80 ° C. In this case, it may be stored frozen at −18 ° C. to −30 ° C., which is a general storage temperature range for ordinary frozen foods. However, protein denaturation and coagulation in raw yuba during frozen storage and soy milk for storage It is preferable to store it frozen in a temperature range of -30 ° C to -80 ° C, which is a lower temperature range.

  The method of thawing the raw yuba and the soy milk for storage after freezing in the frozen container is preferably thawed under running water, which is generally recommended as a method for thawing frozen foods. If the temperature of flowing water is in the range of 0 ° C. to 20 ° C., the taste, texture, and color of the raw yuba after thawing are the same as freshly made fresh yuba. Moreover, in the present invention, since the raw material soymilk used for the raw yuba does not contain sugar, the original taste of the raw yuba can be maintained.

In the above method, the freezing container is a sealable container,
In the freezing step, it is preferable that the freezing container containing the raw yuba and the soy milk for storage is sealed and immersed in a liquid alcohol cooled to a temperature in the range of −20 ° C. to −80 ° C. By employ | adopting said method, the raw yuba in the container for freezing and the soymilk for preservation | save can be cooled to the temperature contained in the range of -20 degreeC--80 degreeC in a short time, and can be frozen. As a result, the raw yuba in the freezing container and the soy milk for storage can rapidly pass through the maximum ice crystal generation temperature zone (−1 ° C. to −5 ° C.), so that the ice formed inside the raw yuba Crystal growth can be suppressed, and damage to raw yuba during freezing can be reduced.

  According to the present invention, raw yuba can be stored frozen without reducing the texture and flavor. In addition, when frozen frozen yuba is thawed, it does not change color greatly, so that it is possible to obtain a frozen yuba equivalent to freshly made yuba, not only in terms of texture and flavor, but also in appearance. Can do. In particular, Kumiage Yuba, which is manufactured by scooping up the film before the film is completely formed, contains a large amount of soy milk due to its production method. According to the present invention, the texture, flavor, and color can be maintained even when Kumage yuba is stored frozen.

The figure which shows the instrument for liquid freezing raw yuba. A photograph showing the appearance of Kumage Yuba with a texture evaluation of “× or Δ”, “◯”, or “◎”. The graph which shows the temperature change inside the raw yuba when the raw yuba is liquid frozen. A photograph of Kumage Yuba prepared using soymilk for preservation containing 42% by weight of trehalose, gas frozen at −40 ° C., stored at −40 ° C. for 2 weeks, and then slowly thawed. A photograph of Kumage Yuba prepared using storage soymilk containing 42% by weight of trehalose, gas frozen at −40 ° C., stored at −40 ° C. for 2 weeks, and then thawed under running water. The photo on the right shows a picture of Kumeage yuba prepared using preservative soy milk that does not contain trehalose at −40 ° C., and stored at −40 ° C. for 2 weeks, and then thawed under running water. A photograph is shown when the frozen yuba prepared using the soy milk for storage not contained is liquid frozen at −40 ° C., stored at −40 ° C. for 2 weeks, and then thawed under running water. The left-hand side is a photograph of the frozen yuba prepared using preservative soymilk containing 42% by weight of trehalose, gas frozen at −40 ° C., stored at −40 ° C. for 2 weeks, and taken out of the freezer. The right side shows a photograph of the pumped-up yuba prepared using soymilk for storage containing 42% by weight of trehalose, liquid frozen at −40 ° C., stored at −40 ° C. for 2 weeks, and then removed from the freezer. A photograph of Kumage Yuba prepared using preservative soymilk that does not contain trehalose at −80 ° C., gas frozen, degassed, stored at −20 ° C. for 2 weeks, and then thawed under running water. Kumage yuba prepared using soy milk for storage without trehalose was put into a plastic tube, frozen at −80 ° C., frozen at −80 ° C. or −20 ° C. for 2 weeks, and then thawed under running water. Photo of things.

Hereinafter, the manufacturing method of the frozen raw yuba which concerns on this invention is demonstrated concretely.
In developing the manufacturing method according to the present invention, the inventor made frozen raw yuba by changing the sugar concentration in the soymilk for storage, the freezing temperature and the freezing method of the raw soymilk and the soymilk for storage, and the frozen storage temperature. In addition, a test was conducted to examine the taste, texture and color of the raw yuba after thawing. Hereinafter, this test will be described.

(1) Preparation of soy milk Water is added to soybeans soaked in water and ground to obtain raw kure. Subsequently, raw Kure was heated, and the resulting boiled Kure was squeezed to obtain soy milk. At this time, the amount of water to be added when grinding soybeans and the amount of water to be added to boiled rice were adjusted so that the Brix value of the obtained soymilk would be 4 to 6 degrees or 7 to 9 degrees. Moreover, according to the general manufacturing method of soymilk, the parameters of the grinder (grinding rotation speed, grinding time, etc.), the temperature and time for heating the raw koji, etc. were appropriately adjusted. Hereinafter, soy milk having a Brix value of 4 to 6 degrees is referred to as raw soy milk for raw yuba, and soy milk having a Brix value of 7 to 9 degrees is referred to as raw material soy milk for storage soy milk.
Next, trehalose is added at a ratio of 31% by weight, 42% by weight, and 62% by weight to the raw material soymilk for storage soymilk, and cooled to around 15 ° C., respectively. As a comparative example, a soy milk for storage not containing trehalose is also prepared and cooled to around 15 ° C.

(2) Manufacture of Kumiage Yuba The raw soymilk having the above Brix value of 4 to 6 is placed in a kettle, and the kettle is heated with steam to maintain the temperature of the raw soymilk at around 80 ° C. Then, when a thin film starts to form on the liquid surface of the raw soymilk, scoop up this film with chopsticks and put it in a yuba preparation container. This yuba preparation container is a separate container from the freezing container. If the scooped film exceeds a predetermined thickness, the soft texture of the finished raw yuba is impaired, so be careful when scooping the film.

  When scooping up the film with chopsticks, a lot of raw soy milk adheres to the film. Therefore, the yuba preparation container contains not only the film but also the raw material soymilk. Since the temperature of the film and the raw material soymilk is high for a while after being put in the yuba preparation container, the coagulation of the protein contained in the film and the raw material soymilk proceeds. Therefore, preservation soy milk cooled to about 15 ° C. at an appropriate timing is added to the yuba preparation container to stop protein coagulation. Thereby, a pumped-up yuba with substantially constant viscosity and softness is obtained.

  In addition, in this test, when making about 200 g of raw yuba (that is, when about 200 g of film and raw material soymilk are put in a yuba preparation container), 10-20 mL of soy milk for storage is added, but this is not limitative. Not. The addition amount of the soy milk for storage may be appropriately adjusted according to the type of soybean, the working temperature, and the like. The pumped-up yuba and the soy milk for preservation in the yuba preparation container obtained as described above were placed in the same amount in a freezing container, and the air in the freezing container was evacuated with a vacuum packaging machine and sealed. Here, a bag made of a sheet material obtained by bonding a nylon film and a Roden poly (low density polyethylene (LDPE)) film was used as a freezing container.

(3) Freezing treatment of Kumiage Yuba (3-1) Freezing treatment method A sealed freezing container containing Kumiage Yuba and soy milk for storage is cooled in running water. And when the temperature of the pumped-up yuba etc. in a container for freezing became 10-20 degreeC, the container for freezing was taken out from flowing water, and it was frozen with the following three types of methods.
(a) Gas freezing: A freezing container is stored in a general freezer (set temperature: -20 ° C, -40 ° C, -60 ° C, -80 ° C).
(b) 3D quick freezing: A freezing container is housed in a freezer (set temperature: −40 ° C.) of a type that blows cold air from three directions toward the inside.
(c) Liquid freezing: As shown in FIG. 1, alcohol 1A is placed in a rectangular container 1, and a freezing container (bag) 2 is immersed in the container (a set temperature:- Housed in 20 ℃, -40 ℃, -60 ℃, -80 ℃). When the freezing temperature was −80 ° C., alcohol having an alcohol content of 75 ° C. was placed in the rectangular container 1, and in other cases, 68.9 ° C. alcohol was placed in the rectangular container 1.

(3-2) Type of freezer used for freezing treatment The freezer shown in the following table was used.

(3-3) Freezing time
In any of (a) to (c), the temperature inside the raw yuba in the freezing container was measured with a temperature sensor, and the temperature reached −20 ° C., −40 ° C., −60 ° C., and −80 ° C. The container for freezing was taken out from the freezer. The freezing times of (a) to (c) were as follows.
(a) 8 hours
(b) 1 hour 30 minutes
(c) 20 minutes

(4) Refrigerated storage With the frozen soy milk and the soy milk for storage kept in the freezing container, the internal temperature is set to -20 ° C, -35 ° C, -80 ° C for 2 weeks, And stored for 1 month. Here, the pumped-up yuba after frozen storage is also called “frozen pumped-up yuba”.

(5) Thawing The temperature and period shown in (4) and the pumped-up yuba stored in a freezer and the soy milk for storage were thawed under the following conditions while being put in the freezing container.
(a) Thawing in running water (0-20 ° C) for about 1 hour (flowing water thawing)
(b) Thawing (slow thawing) over about 8 hours in a low temperature (0 ° C to 10 ° C) environment

(6) Results Eight panelists evaluated the taste and texture of the dried yuba after thawing. The taste and texture were evaluated as follows.
◎: Equivalent to freshly made pumpkin yuba ○: Slightly inferior to freshly made pumpkin yuba, but commercially available Note that FIG. 2 is a photograph of the appearance of Kumage Yuba with a texture evaluation of x, Δ, ○, or ◎.

Moreover, the color of the pumped-up yuba immediately after taking out from the freezer in order to defrost was evaluated as follows.
◎: White equivalent to freshly made pumpkin products ○: Light brown to white △: Brown to light brown ×: Dark brown to light brown In addition, assuming the state of frozen pumped yuba when selling at stores, freezer Even if the evaluation at this time is any of "◎" to "x", the color of Kumiage Yuba is almost the same as that of the freshly made Kumage Yuba. Became white.

  As a result, what was slowly thawed was evaluated as Δ or × for the taste and texture regardless of the concentration of trehalose contained in the soymilk for storage, the freezing method, the temperature of the frozen storage, and the storage period. This means that the damage received by the pumped-up yuba due to slow thawing is great. On the other hand, the samples that had been thawed with running water had different taste and texture evaluations depending on the concentration of trehalose contained in the soymilk for storage, the freezing method, and the temperature of the frozen storage. Table 2 shows the evaluation results of the pumped-up yuba with a frozen storage period of 2 weeks. In Table 2, the shaded column indicates that no test was performed. Note that the evaluation result of Kumiage Yuba with a frozen storage period of one month was almost the same as the evaluation result of Kumiage Yuba with a frozen storage period of two weeks, and thus the description thereof is omitted here.

(6) Discussion (6-1) Frozen pumped-up yuba of a comparative example in which trehalose is not added to the soymilk for storage (sugar concentration is 0%). When the temperature is set to 80 ° C., when the freezing temperature is set to −60 ° C. and the liquid is frozen, and the frozen storage temperature is set to −60 ° C., the evaluation of color, taste, and texture is “◎” or “○”. there were.

  On the other hand, when the freezing temperature was −80 ° C. or −60 ° C. and the frozen storage temperature was −20 ° C., the color evaluation was “◎” or “◯” in both gas freezing and liquid freezing. In addition, the evaluation of taste and texture was “×”, which was much inferior to freshly made pumpkin yuba.

  When the freezing temperature was −40 ° C. and 3D quick-frozen and the frozen storage temperature was −35 ° C., the texture was evaluated as “x”, which was very inferior to freshly made pumpkin yuba. And the evaluation of the taste was “△”, which was only slightly inferior to freshly made pumpkin yuba. In addition, when the freezing temperature was −40 ° C. and the liquid was frozen, and the frozen storage temperature was −35 ° C., the evaluation of the texture was “×”, which was very inferior to freshly made pumpkin, The color evaluation was “◎”, and the taste evaluation was “Δ”.

  On the other hand, when the freezing temperature is −40 ° C. and 3D quick-frozen and the frozen storage temperature is −20 ° C., the color evaluation is “△”, which is slightly inferior to freshly made pumpkin. In addition, both the freshness evaluation and the texture were “x”, which was very inferior to freshly made pumpkin yuba. In addition, when the liquid was frozen at a freezing temperature of −40 ° C. and the frozen storage temperature was −20 ° C., the evaluation of color was “」 ”, but the evaluation of taste and texture was“ × ”. It was very inferior to freshly made pumpkin yuba.

  When the freezing temperature was −20 ° C. and the liquid was frozen and the frozen storage temperature was −20 ° C., the evaluation of the color when thawed was “◯”, which was almost the same as the freshly made yuba. The evaluation of taste and texture was “x”, which was very poor. When the freezing temperature was −20 ° C. and the gas was frozen and the frozen storage temperature was −20 ° C., all the evaluations of color, taste and texture were “x”.

  From the above results, except when the gas is frozen at −20 ° C., even if trehalose is not included in the storage soymilk, the color of the pumped-up yuba is not greatly deteriorated by freezing and freezing, but the freezing temperature, It was found that the taste and texture deteriorated depending on the freezing method and frozen storage temperature. Specifically, even if trehalose is not contained in the soy milk for storage, the freezing temperature is set to −40 ° C. or lower, and the frozen storage temperature is set to a temperature lower than −20 ° C. It is possible to avoid this, and by making the freezing temperature lower than −40 ° C. and the frozen storage temperature lower than −35 ° C., it is possible to avoid all the deterioration of color, taste and texture. I found it possible.

(6-2) Frozen pumped-up yuba using preservative soymilk containing 31% by weight and 42% by weight of trehalose Even if frozen and frozen at any method and temperature, the evaluation of taste and texture is “◯” or It was “◎” and it was the same as or slightly inferior to freshly made Yuba.
When the liquid was frozen, the evaluation of the color was “◯” or “◎” regardless of the freezing temperature and the freezing storage temperature. On the other hand, when the gas was frozen, the evaluation of the color when the freezing temperature was −80 ° C. and the frozen storage temperature was −20 ° C. was “◯”, but the evaluation of the other colors was “Δ” or “ × ”, inferior to freshly made pumpkin yuba. From this, it was found that by using soy milk for storage containing 31% by weight and 42% by weight of trehalose, deterioration of color, taste and texture due to freezing and freezing storage can be suppressed. In particular, even when stored frozen at −20 ° C., the color, taste and texture hardly deteriorated, so the color, taste and texture of frozen storage (around −20 ° C.) in a general household refrigerator It seems that the degradation of the can be suppressed.

(6-3) Frozen Kumage Yuba using storage soymilk containing 62% by weight of trehalose Even when frozen and frozen at any method and temperature, the texture evaluation is “◎” or “○” Although it was the same as or slightly inferior to freshly made pumpkin yuba, the taste evaluation was “△”, which was worse than freshly pumped yuba. Deterioration of taste seemed to be greatly affected by trehalose contained in a large amount in preservative soymilk. On the other hand, the evaluation of the color was almost the same as the case of using the preservative soymilk containing 31% by weight and 42% by weight of trehalose.

FIG. 3 shows the results of examining the temperature change of the pumped-up yuba when the liquid is frozen. In this case, alcohol 2A (alcohol content: 68.9 degrees) having a temperature of −35 ° C. is placed in a plastic rectangular container 2 having a size of 170 × 110 × 30 (mm ³ ), and 350 g of pumped-up yuba is stored therein. The freezing container (sealed bag) 1 was immersed to accommodate the rectangular container 2 in the freezer.
As shown in FIG. 3, the temperature of the pumped-up yuba, which was about 10 ° C. when housed in the freezer (at the time of charging), gradually decreased, and about 8 minutes 30 from about 9 minutes to 17 minutes 30 seconds later. Passed through the maximum ice crystal formation zone in seconds. Thereafter, the temperature dropped rapidly until 23 minutes after removal from the freezer, and the temperature of the pumped-up yuba when it was removed was about -22.5 ° C.

In this way, in liquid freezing, the temperature of Kumage Yuba rapidly decreases, and the passage time of the maximum ice crystal formation zone is particularly short, so the particle size of ice crystals generated in the tissue of Kumage Yuba becomes smaller, and freezing Occasionally, the damage received by pumping yuba is reduced.
In addition, when the particle size of ice crystals purified in the tissue of Kumage Yuba is small, the amount of storage soymilk that covers the surface crystals per volume of ice crystals increases, and further, the amount of sugar contained in the storage soymilk When the amount is large, many saccharides cover the ice crystals (that is, the ice crystals are protected by the saccharides).
From the above, it is considered that the most excellent effect (inhibition of deterioration of color, taste, and texture due to freezing and freezing storage) can be obtained when Kumiage yuba is liquid frozen using soy milk for storage containing saccharides.

[Example]
Based on the above results, the results of producing frozen pumped-up yuba will be described with reference to FIGS.
FIG. 4 is a photograph of Kumage yuba prepared using preservative soymilk containing 42% by weight of trehalose, gas frozen at −40 ° C., frozen at −40 ° C. for 2 weeks, and then slowly thawed. FIG. 5 is a photograph of a frozen yuba prepared using a soymilk for preservation containing 42% by weight of trehalose, frozen in gas at −40 ° C., frozen at −40 ° C. for 2 weeks, and thawed under running water. is there.
As shown in FIG. 4, this frozen pumped-up yuba became hard due to protein denaturation during thawing. The taste after thawing was also bad. On the other hand, the frozen pumped-up yuba shown in FIG. 5 was equivalent to freshly pumped-up yuba in color, taste and texture.

  The left side of FIG. 6 is a photograph of Kumage yuba prepared using preservative soy milk that does not contain trehalose, gas frozen at −40 ° C., frozen at −40 ° C. for 2 weeks, and then removed from the freezer. The right side is a photograph of Kumage yuba prepared using preservative soymilk that does not contain trehalose, liquid frozen at −40 ° C., frozen at −40 ° C. for 2 weeks, and taken out of the freezer.

  The left side of FIG. 7 shows a case where Kakuage yuba prepared using storage soymilk containing 42% by weight of trehalose is gas frozen at −40 ° C., frozen at −40 ° C. for 2 weeks, and then taken out of the freezer. The photo is on the right, when the dried yuba prepared using preservative soymilk containing 42% by weight of trehalose is liquid frozen at -40 ° C, frozen at -40 ° C for 2 weeks, and then taken out of the freezer It is a photograph of.

  As shown in FIG.6 and FIG.7, when trehalose is not included in the soy milk for storage, and when it is included, the case of liquid freezing at −40 ° C. is more than the case of gas freezing at −40 ° C. In addition, it was found that the color of pumped-up yuba and soy milk for storage after freezing was white, and discoloration was suppressed by liquid freezing.

  Moreover, as can be seen from the comparison between FIG. 6 and FIG. 7, when frozen by the same method, the color of the frozen pumpkin after frozen storage regardless of whether or not 42% by weight of trehalose is contained in the soy milk for storage. There was no big difference. That is, when frozen in liquid, the color of the frozen pumpkin after freezing is white, regardless of whether 42% by weight of trehalose is contained in the soy milk for storage, or brown when frozen in gas . From this, it can be said that by freezing in liquid, it is possible to suppress discoloration of the frozen pump-up after freezing storage (that is, before thawing).

  FIG. 8 is a photograph of Kumage yuba prepared using preservative soymilk that does not contain trehalose, which was frozen at −80 ° C., degassed, and stored frozen at −20 ° C. for 2 weeks. As can be seen from the comparison between FIG. 6 and FIG. 8, the frozen kumage yuba produced by this method had a very white kumage yuba color after cryopreservation even if trehalose was not added to the soymilk for storage. However, the texture was impaired by two weeks of freezing storage at -20 ° C.

FIG. 9 shows that the soy milk containing preservatives not containing trehalose is put into a plastic tube with a lid and the frozen yuba is gas frozen at −80 ° C. and then frozen at −80 ° C. or −20 ° C. It is a photograph after refrigerated for a week and then thawed under running water.
The left plastic tube in FIG. 9 is stored frozen at −80 ° C., and the right plastic tube is stored frozen at −20 ° C. As can be seen from these comparisons, the pumped-up yuba stored frozen at −80 ° C. was uniformly smooth, and the pumped-up yuba stored frozen at −20 ° C. was partially solidified.

  In addition, although the above-mentioned test was done about the pumped-up yuba, it can be easily analogized that the same result can be obtained even when the raised yuba is frozen. That is, pulling yuba is manufactured by scooping up the film after the film is completely formed on the surface of the heated soymilk, so that the texture is not as soft as kumage yuba, and the liquid occupying the contained yuba The percentage of soy milk is small. The deterioration and discoloration of the taste and texture due to freezing and frozen storage are due to denaturation and coagulation of proteins contained in soy milk. Therefore, if it is a condition that can suppress the deterioration and discoloration of the taste and texture when Kumiage Yuba is frozen and frozen, it can also suppress the deterioration and discoloration of the taste and texture due to freezing and freezing in the pulled Yuba. Can do.

DESCRIPTION OF SYMBOLS 1 ... Rectangular container 1A ... Alcohol 2 ... Freezing container

Claims (4)

a) Soymilk preparation step of preparing soymilk for storage by adding 31 to 50% by weight of trehalose to raw soymilk;
b) Raw yuba produced using raw soy milk to which no sugar is added, and a freezing preparation step for storing the preservative soy milk in a freezing container;
c) a freezing step in which the raw yuba and the soy milk for storage stored in the freezing container are cooled to a temperature range of −60 ° C. to −80 ° C. and frozen;
d) the raw curd and storage of soy milk in the freezing container in a frozen state, possess a cryopreservation step of storing at a temperature range falling within the scope of -18 ℃ ~-80 ℃,
The Brix value of the raw material soymilk used for the storage soymilk is 7 to 9 degrees,
The method for producing frozen raw yuba, wherein the raw soymilk raw milk has a Brix value of 4 to 6 degrees . a) Soymilk preparation step of preparing soymilk for storage by adding 31 to 50% by weight of trehalose to raw soymilk;
b) A raw preparation prepared using raw soymilk to which no saccharide is added, and the preservative soymilk stored in a freezing container, and the freezing preparation step for sealing the freezing container ;
c) The sealed freezing container is immersed in liquid alcohol cooled to a temperature range included in the range of −20 ° C. to −80 ° C. , and the raw hot water leaf and the storage stored in the freezing container A freezing process for freezing soymilk ;
d) the raw curd and storage of soy milk in the freezing container in a frozen state, possess a cryopreservation step of storing at a temperature range falling within the scope of -18 ℃ ~-80 ℃,
The Brix value of the raw material soymilk used for the storage soymilk is 7 to 9 degrees,
The method for producing frozen raw yuba, wherein the raw soymilk raw milk has a Brix value of 4 to 6 degrees . In the manufacturing method of the frozen raw yuba according to claim 1 or 2,
  In the soymilk preparation step, 31 to 42% by weight of trehalose is added to the raw material soymilk. By scooping up the film formed on the liquid surface of the raw material soymilk by heating the raw material soymilk to which no sugar is added at a temperature in the range of 70 ° C. to 90 ° C., and storing this in the freezing container, Comprising the step of preparing the cryocontainer in which the raw yuba is housed,
The frozen raw yuba according to any one of claims 1 to 3, wherein the frozen soy milk is prepared by adding the preservative soymilk having a temperature in the range of 10 ° C to 20 ° C to the freezing container. Manufacturing method.