JPH11169123A - Sterilization method for soybean milk and production of sterile bean curd - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high pressure sterilizing method suitable for soybean milk. SOLUTION: The sterilizing method comprises sterilizing soybean milk in a condition heating at 70-100 deg.C under the pressure of 400-1000 Mpa for 5-60 minutes. A sterile bean curd is made from the obtained soybean milk. The sterile soybean milk is obtained from high pressure sterilizing treatment by removing solid contents in the soybean milk in centrifugal separation process as the pretreatment of the high pressure sterilizing process, and deaeration removes bubble and dissolved oxygen in the soybean milk and prevents the soybean milk from bubbling in the surface in production of the bean curd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for sterilizing soymilk in which heat-resistant microorganisms of soymilk are effectively killed, and a method for producing aseptic tofu using the sterilized soymilk.

[0002]

2. Description of the Related Art Heat sterilization, a method using chemicals, and a method using radiation such as ultraviolet rays are known for sterilizing foods. Is the most.

[0003] The soymilk targeted by the present invention is obtained by extracting and squeezing from soybean, and soymilk is generally used as a raw material for processed foods such as tofu / fried oil, beverages, desserts and the like. A method of sterilizing soy milk by heat as one step of the sterilization method or the method of producing aseptic tofu is disclosed in, for example, JP-B-55-45172, JP-B-56-39865, and JP-B-3-49.
No. 547, Japanese Patent Application Laid-Open No. 3-272660, and the like.

As a method for producing aseptic tofu, there is disclosed a method of filling a paper container or a plastic container with soymilk and a coagulant disclosed in Japanese Patent Publication No. 3-49547 or JP-A-3-272660, which is an invention of the present applicant. There is a way.

[0005] The bitterness of the coagulant component of soy milk is 9
If 9.5% or more of magnesium chloride is used, the reaction rate when bittern is mixed with soymilk is extremely fast, and when both are mixed, they solidify before filling in a container. In order to avoid the above-mentioned problems, soy milk cooled to 20 ° C. or less after heat sterilization and mixed immediately before filling the container with the bittern cooled to 20 ° C. or less after heat sterilization to produce aseptic tofu in a container A method is disclosed.

[0006] Further, if the tofu in a container is subjected to a retort sterilization treatment of heating to about 120 ° C, the flavor of the tofu is impaired. The mixed liquid of soymilk and the coagulant is filled in a sterilized oxygen-barrier hard plastic cup-shaped container in a sterile chamber, and a sterilized oxygen-barrier lid is filled in the filled container in the chamber. A method for producing tofu in a container is disclosed in which the sealed container is heated and the sealed container is heated to solidify a mixed solution in the container.

Further, Japanese Patent Publication No. 4-29331 discloses that
Spores in soy milk that are not completely killed by heat treatment
There is disclosed a method for producing soymilk which is completely sterilized by holding at a low temperature for a long time as follows, and then heat sterilized for a short time.

[0008] If the food is sterilized or sterilized by heating, the quality and flavor of the food may be impaired.
A method of sterilizing food under high pressure has also been developed. JP-A-2-255068 and JP-A-2-31257
No. 7 discloses 500 to 10,000 kgf / c each.
m ² , 60-110 ° C and 1,000-10,000k
A method of sterilizing foods and the like at gf / cm ² and 30 to 130 ° C. is disclosed.

[0009]

In the case of producing aseptic tofu, if the soymilk is overheated, the coagulation state is also deteriorated. For this reason, it was difficult to produce a bitter natural coagulant with good flavor and aseptic tofu with magnesium chloride. In the case of producing aseptic tofu with soy milk heated at a high temperature, calcium sulfate, GDL (glucono delta lactone) or the like is used as a coagulant. Therefore, even if tofu was produced, it was not satisfactory in texture or flavor. In addition, tofu obtained from soy milk sterilized at 120 ° C. or lower,
Because the soy milk was not completely sterilized, the resulting tofu could only be labeled with a short shelf life.

Further, simply applying the method of sterilizing food by high-pressure treatment described in JP-A-2-255068 and JP-A-2-31577 to soymilk does not provide completely sterile soymilk. However, since high-pressure sterilization is generally a method that does not impair the quality and flavor of foods, if a high-pressure sterilization method suitable for soy milk can be developed, there is a possibility that aseptic tofu with better quality and flavor than conventional products can be produced. is there. An object of the present invention is to provide a high-pressure sterilization treatment method suitable for soymilk, and to provide a processed product of soymilk such as tofu having excellent quality and flavor.

[0011]

The above object of the present invention is attained by the following constitution. That is, this is a method for sterilizing soymilk in which soymilk is sterilized under a high-pressure treatment condition at 400 MPa or more and 1000 MPa or less for 5 minutes or more and 60 minutes or less under the condition heated to 70 ° C or more and 100 ° C or less.

When the pressure is less than 400 MPa, the sterilizing effect is insufficient, and when the pressure exceeds 1000 MPa, the equipment deviates from the commercial range and becomes very expensive. When the heating temperature is less than 70 ° C., the sterilizing effect becomes insufficient. Above 100 ° C., the flavor, texture and aroma of soymilk are inferior. If the high-pressure treatment time is less than 5 minutes, there is no bactericidal effect, and if it exceeds 60 minutes, the soymilk deteriorates.

Further, a feature of the present invention is that any one of the following two treatments is performed as a pretreatment of the high-pressure sterilization treatment. As a result of the pretreatment of the soymilk, aseptic soymilk is obtained, and Highly commercial valued tofu can be obtained from soy milk.

(1) Removal of solid content The present inventors have found that if there is a large amount of solid content in soymilk, the soymilk does not become aseptic even if heat and high pressure treatment is performed. Therefore, it is necessary to reduce the solid content in soy milk as much as possible before the high-pressure treatment. As a method for removing solids in soy milk, a filtration method, a centrifugation method, or the like can be used, but the centrifugal method is the best method because of a large amount of treatment in a short time.

The centrifugal force is 14.5 cm in the radius of gyration.
1,000-5,000 rpm, preferably 3,000
４，4,000 rpm. Centrifugal force is 1,000 rpm
If it is less than 50%, solids can hardly be separated. If the centrifugal force exceeds 5,000 rpm, the degree of separation of solids will not be improved. The degree of sterilization by the treatment is not improved, and the quality of the tofu produced using the soymilk is not significantly improved, and only the cost of the centrifugation treatment operation is increased.

The content of solids in the soy milk is determined by a turning radius of 14.
By centrifugation at 5 cm, 3000 rpm (1.460 × G) for 10 minutes, the concentration is reduced to 5% or less, preferably 2% or less.

(2) Deaeration If soy milk contains a large amount of air bubbles and dissolved oxygen, not only does soy milk not become sterile even when heat and high pressure treatment is performed,
The tofu obtained from soy milk containing a large amount of bubbles and dissolved oxygen has air bubbles scattered on its surface, which impairs commercial value.

Degassing was performed at 300 to 780 mmHg, preferably 600 to 760 mmHg. Degas treatment 300
Degassing is scarcely performed even when performed at less than mmHg. In addition, when the pressure exceeds 780 mmHg, degassing has sufficiently proceeded, so that the cost for degassing needlessly increases only.

In the above method, the heating and the high-pressure treatment of the soymilk are performed simultaneously.
After heat treatment at a temperature of 00 ° C. or less,
A method of sterilizing under high-pressure treatment conditions at a pressure of 000 MPa or less for 5 minutes or more and 60 minutes or less may be used.

The advantage of this sterilization method is that when heat treatment is carried out at 70 ° C. or higher, the heat treatment time becomes long. Therefore, in the case of treating a large amount of soy milk, the soy milk is heated in advance and then efficiently treated by high pressure. Sterilization treatment is possible. In this case, the heat treatment may be performed in a high-pressure treatment chamber or may be performed using a heat treatment device different from the high-pressure treatment chamber.

When the heat treatment and the high pressure treatment are performed at the same time, the high pressure chamber is made thick to withstand high pressure.
Heating with a heater or the like has the disadvantage that the efficiency of heat transfer is low and that the temperature rise time is long.

In the above method, the soymilk is subjected to a high-pressure treatment while the liquid is put in a high-pressure treatment chamber in a liquid state. Here, the container of the present invention refers to a plastic container or a paper packaging material.

A method for producing aseptic tofu, wherein the soymilk obtained by the above-mentioned sterilization method and a sterilized or sterilized coagulant are filled in a gas barrier container under aseptic conditions, mixed and sealed, is also included in the scope of the present invention. belongs to.

In the method for producing tofu of the present invention, the soymilk and the coagulant before the sterilization treatment are filled in a container having gas barrier properties, mixed, sealed, and heated to 70 ° C. or more and 100 ° C. or less. In a state, 400 MPa or more, 1000 MPa or less for 5 minutes or more, for 60 minutes or less, for a method of producing aseptic tofu treated under high pressure treatment conditions, or in a container having a gas barrier property of soy milk and a coagulant before sterilization treatment. After filling, mixing, sealing, and heating at 70 ° C. or more and 100 ° C. or less, a method for producing aseptic tofu, which is treated under high-pressure treatment conditions at 400 MPa or more and 1000 MPa or less for 5 minutes or more and 60 minutes or less. included.

The present inventors have found that the centrifugal separation treatment of the above (1) and the (2) of the above (2) when soy milk is used as a raw material for uses other than tofu, for example, for protein processed foods such as fried foods, drinks, and desserts. By the deaeration treatment, the effect of the high-pressure sterilization treatment is improved.

In addition, the high-pressure sterilization treatment of the soymilk of the present invention can obtain aseptic soymilk even if it is performed without an antioxidant, an antibacterial agent, a preservative, an emulsifier, etc. The food is a health food, and a food having a high natural preference can be provided.

JP-A-2-255068 discloses an invention in which various foods are subjected to high-pressure treatment without adding an antioxidant, an antibacterial agent, etc., but the viable cell count does not become zero even after the high-pressure treatment. In contrast, in the case of the present invention, since the high-pressure treatment was performed after the centrifugal treatment and the deaeration treatment, the viable cell count was zero in the soymilk and tofu after the high-pressure treatment.

Thus, according to the present invention, aseptic soymilk without food additives (soymilk for beverages, soymilk used for soymilk drinks, etc.) and aseptic tofu can be obtained from the soymilk. The high-pressure treatment in the present invention is a method of pumping a liquid serving as a pressure medium into a high-pressure chamber having a limited volume, which is well known, by a pump (pump pressurization method), or a method in which a piston is pushed into the high-pressure chamber and the A method of reducing the internal volume (piston pressurizing method) can be applied.

[0029]

Embodiments of the present invention will be described below. First, the production of aseptic tofu to be filled in a plastic container was performed according to the method described in Japanese Patent Publication No. 3-49547. Further, in order to compare the tofu obtained by the high-pressure sterilization treatment with the tofu obtained by the heat sterilization treatment, aseptic tofu filled in a plastic container by the heat sterilization treatment method described in JP-B-3-49547. I got

(Method of the Present Invention) FIG. 1 shows a process according to the method of the present invention. According to a conventional method, soymilk was prepared as follows. The washed soybeans are immersed in water for a predetermined time, and after draining, a predetermined amount of water is added to the water-absorbing soybeans, and ground with a grinder to obtain raw gou. To this was added a mixture of peeled flake soybeans in a predetermined amount of water, and the mixture was boiled in a steaming can to separate okara, and soy milk was obtained.

The obtained soymilk was centrifuged at 3,000 to 4,000 rpm (currently 3,540 rpm) for 10 minutes using a centrifuge to reduce the solid content to 2% or less. The soy milk after separating the solid content is 760
Degassing was performed for 10 seconds at mmHg.

Then, under two high-pressure conditions of 400 MPa and 700 MPa, the heating temperature was increased to 60 ° C., 70 ° C., 80 ° C.
The high-pressure treatment was performed at a temperature of 90 ° C., 90 ° C., and treatment times of 5, 20, and 40 minutes, respectively. Thereafter, the soymilk pasteurized is cooled at a temperature of 15.5 ° C. using cooling water and stored in a sterile tank.

The bittern is also heated and cooled by the same method and under the same conditions as for soymilk, and stored in a sterile tank for bittern. As the bittern, magnesium chloride having a purity of 99.5% was used.

Prescribed amounts of sterilized soy milk and sterilized bittern are respectively supplied to a filling device (not shown), mixed in the filling device, and supplied to a sterilized plastic container in a sterile chamber (not shown). After that, the container is sealed with a sterilized lid and heated at 90 ° C.
It is cooled and made into a sterile tofu product.

When a paper container is used instead of a plastic container, a sterilized packaging material is filled with high-pressure-treated soymilk and sterilized bittern, the packaging material is sealed, and then heat-treated.

As a comparative example, tofu in a plastic container was produced by the heat sterilization method described in Japanese Examined Patent Publication No. 3-49547, using the same soymilk raw material and the same raw material as in the procedure shown in FIG.

The soymilk obtained by the same production method using the same raw materials as the present invention is first degassed, and then a heating heat exchanger using soymilk as a heat medium and a cooling medium using cooling water as a cooling medium. Pass sequentially through the heat exchanger and store in a sterile tank. The heating temperature of the soy milk in the heating heat exchanger is 135 ° C.,
The transit time of the heat exchanger is 2 seconds. The cooling temperature in the cooling heat exchanger is 15.5 ° C., and the passage time of the heat exchanger is 2 seconds.

The bittern is heated and cooled in the same manner and under the same conditions as for soymilk, and stored in a sterile tank. The mixing of the sterilized soymilk and the bittern, filling in a plastic container, and sealing with a lid of the container are the same as the high-pressure sterilization method of the present invention.

Further, a tofu in a paper container can be produced by filling a sterilized soymilk and bittern mixture using a packaging material instead of the plastic container and sealing the packaging material.

The results of confirming the sterility of the soymilk obtained by the high-pressure treatment method of the present invention are shown in Table 1.

[Table 1]

In the measurement of the bacterial count of the soymilk before the high-pressure treatment,
Bacterial counts were detected at 10 ¹ to 10 ⁴ / ml. Then, the bacterial count of the soymilk immediately after the high-pressure treatment was measured in the same manner. However, as shown in Table 1, the bacteria were not detected at 70 ° C. and at 400 MPa or more.

Here, the bacterial test method for soymilk is as follows. After soy milk before and after the high pressure treatment was grown at 35 ° C. for 5 days, 1 ml of the soy milk was mixed with a standard agar medium and coated on a plate count agar medium containing BCP, and cultured at 35 ° C. for 48 hours. Then, the presence or absence of the bacterial count was confirmed.

In order to confirm the sterility of the soymilk obtained by the high-pressure treatment method of the present invention and the high-temperature heat treatment method of the comparative example, the soymilk after the high-pressure treatment was grown in a thermostat at 35 ° C. for 5 days. After that, the number of bacteria was measured. As shown in Table 2, no bacteria were detected in any case and it was found that the bacteria were sterilized.

[0044]

[Table 2]

Table 3 shows the results of a sensory test of the soymilk obtained by the high-pressure treatment according to the embodiment of the present invention and the soymilk obtained by the high-temperature heat treatment of the comparative example.

[Table 3]

The conditions for high-pressure treatment of soymilk are 70 ° C. and 700 MPa
a, 5 minutes, high-temperature heat treatment conditions: 128 ° C., 11
Seconds. As shown in Table 3, according to the sensory test performed by the panelists, the tofu using the soymilk obtained by the high-pressure treatment was superior to the soymilk obtained by the high-temperature heat treatment method in both flavor and texture.

Next, Table 4 shows the results of a sensory test of tofu obtained by using various coagulants in soy milk subjected to high pressure treatment. The conditions for the high-pressure treatment of soy milk are 70 ° C., 700 MPa, and 5 minutes, and the coagulants include magnesium chloride (Category 1), calcium sulfate (Category 2), glucono delta lactone (Category 3), magnesium chloride and glucono delta. A mixture of lactones (Category 4), calcium sulfate and glucono delta lactone (Category 5) were used.

[0048]

[Table 4] From the results in Table 4, it was found that natural magnesium chloride was the most excellent as a coagulant in flavor, texture, aroma, and coagulability.

There are various types of tofu such as silken tofu, cotton tofu, and soft tofu, and different soybeans, soluble solids, or coagulants are used for the respective types. Therefore, the soymilk obtained by the production method of the present invention is It can be suitably used for the production of any tofu.

[0050]

According to the present invention, an antioxidant, an antibacterial agent,
Aseptic soy milk can be obtained without adding additives such as preservatives and emulsifiers. By using such soy milk, it is possible to produce secondary products such as aseptic tofu with excellent flavor, texture, aroma, and coagulability. Became. Moreover, the obtained aseptic tofu could use natural bittern and natural magnesium chloride as a coagulant, and a product with good flavor and excellent texture was obtained. In addition, various coagulants can be used, and tofu of various flavors can be produced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a process for producing aseptic tofu according to an embodiment of the present invention.

FIG. 2 is a diagram showing a process for producing aseptic tofu of a comparative example of the present invention.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Wataru Shimada Wataru No. 10, Taro Yasushi, Kitajima-cho, Itano-gun, Tokushima Prefecture Inside Shikoku Kakoki Co., Ltd. Kobe Steel Co., Ltd. Kobe Research Institute, Kobe Steel Co., Ltd. (72) Inventor Toshikatsu Naoi 2-3-1, Niihama, Araimachi, Takasago City, Hyogo Prefecture Kobe Steel Co., Ltd. Takasago Works

Claims (14)

[Claims] 1. A method for sterilizing soymilk, wherein the soymilk is sterilized under a high-pressure treatment condition at a temperature of not less than 70 ° C. and not more than 100 ° C. at a pressure of not less than 400 MPa and not more than 1000 MPa for not less than 5 minutes and not more than 60 minutes. 2. The method for producing soymilk according to claim 1, wherein the soymilk is filled in a container having gas barrier properties and subjected to heating and high pressure treatment. 3. The method for sterilizing soy milk according to claim 1, wherein soy milk from which solid content has been separated by centrifugation in advance is used. 4. The method for sterilizing soymilk according to claim 1, wherein soymilk previously degassed is used. 5. A method for sterilizing soy milk, which comprises subjecting soy milk to a heat treatment at 70 ° C. or more and 100 ° C. or less, and then sterilizing under high pressure treatment conditions at 400 MPa or more and 1000 MPa or less for 5 minutes or more and 60 minutes or less. 6. The method for producing soymilk according to claim 5, wherein the soymilk previously filled in a container having gas barrier properties is used. 7. The method for sterilizing soy milk according to claim 5, wherein soy milk from which solid content has been separated by centrifugation in advance is used. 8. The method for sterilizing soy milk according to claim 5, wherein soy milk previously degassed is used. 9. A container having gas barrier properties filled with a soymilk obtained by the sterilization method according to claim 1 and a sterilized or sterilized coagulant under aseptic conditions, mixed,
A method for producing aseptic tofu, characterized by sealing. 10. Filling, mixing and sealing a container having gas barrier properties with a soymilk obtained by the sterilization method according to claim 5 and a sterilized or sterilized coagulant under aseptic conditions. A method for producing aseptic tofu, characterized by comprising: 11. Filling a container having a gas barrier property with soy milk and a coagulant before the sterilization treatment, mixing and sealing the mixture, and heating the mixture at 70 ° C. or more and 100 ° C. or less to 400 MPa.
A method for producing aseptic tofu, characterized by treating under a high-pressure treatment condition at a pressure of 1,000 MPa or less for 5 minutes to 60 minutes. 12. A soymilk and a coagulant before the sterilization treatment are filled in a container having a gas barrier property, mixed, sealed, heated at 70 ° C. or more and 100 ° C. or less, and then heated at 400 MPa or more and 1000 MPa or less for 5 minutes. A method for producing aseptic tofu, characterized in that the treatment is performed under high-pressure treatment conditions for 60 minutes or less. 13. A method for producing a processed soymilk food using the soymilk obtained by the sterilization method according to any one of claims 1 to 4. 14. A method for producing a processed soymilk food using the soymilk obtained by the sterilization method according to claim 5. Description: