JPH1156285A - Heating of bean curd and production of bean curd - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for heating bean curd, capable of uniformly heating the whole bean curd and a method for producing bean curd, capable of rapidly heating bean curd without deteriorating quality. SOLUTION: This method for heating bean curd comprises energizing bean curd in a container 12 in which electrode plates 33 and 34 are arranged. On the other hand, the method for producing bean curd comprises a step for promoting coagulation while adding and mixing soybean milk with a coagulating agent consisting mainly of bittern and a step for energizing and heating bean curd 36 produced by aging the coagulated material for a definite time in a container 12 in which electrode plates 33 and 34 are arranged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a method for producing tofu, and more particularly, to a method for heating tofu capable of uniformly heating the entire tofu, and a method for producing tofu using the heating method. .

[0002]

2. Description of the Related Art Conventionally, as a method of heating tofu, a boiling method of immersing in tofu, a method of steaming with steam, and various heating methods using microwaves or the like are known.

[0003] However, the boiling method and the method of steaming using steam transfer heat from the outside of the tofu, and have a problem that a temperature difference occurs between the center and the periphery of the tofu. Further, according to the boiling method or the method of steaming with steam, too much heat is applied to the peripheral portion of the tofu, so that the tofu is easily separated from the water, becomes astringent, and becomes brittle. In addition, the microwave method
Although it is internal heating, because it has the property of concentrating on the corner of the object as the property of radio waves, and the half depth is shallow,
There is a problem that uneven heating occurs.

[0004] On the other hand, it has been conventionally known to carry out electric heating in a box in which a pair of electrode plates are arranged opposite to each other for coagulating soymilk (sometimes referred to as "Joule heating"). In the tofu industry, this is called electronic coagulation, but since the reaction of magnesium chloride is fast, the coagulation reaction is delayed and mixed using soy milk at 30 ° C or lower, and the coagulation is performed by heating over time. (Usually up to 80 ° C. in 10 to 30 minutes).

However, the conventional electronic coagulation not only takes a long time to heat, but also uses electric heating to coagulate soymilk, so that a temperature difference between the upper and lower parts is liable to occur due to heat convection, and from the inside to the periphery, The whole could not be heated uniformly. That is, when the soy milk is heated by heating, when the temperature of the upper part of the mold box is higher than that of the lower part, the thermal conductivity increases and the current flows more easily. There is a problem that heat is radiated only in the surrounding area. Further, in the above-mentioned conventional electronic coagulation, the soymilk is once cooled to 30 ° C. or lower and then the energized heating is performed. However, this cooling has a problem that it takes time.

[0006]

[Problems to be solved by the invention]

Accordingly, an object of the present invention is to provide a method for heating tofu, which can uniformly heat the entire tofu. Another object of the present invention is to provide a method for producing tofu that can rapidly heat tofu without deteriorating the quality of the tofu.

[0008]

The tofu heating method according to the first aspect of the present invention is characterized in that the tofu is electrically heated in a container provided with an electrode plate.

According to the present invention, since the tofu itself is used as a heat medium, heat convection hardly occurs as in the conventional case where electric heating is performed for the purpose of coagulating soymilk, and the entire tofu is uniformly heated. It can be heated uniformly. In addition, it is possible to shorten the energization heating time and reduce the power consumption. In addition, in the conventional electronic coagulation, the soymilk is once cooled to 30 ° C. or lower and then heated by energization. However, the present invention does not require such a large cooling, so that the conventional tofu manufacturing process is not required. Can be simplified in one step, and cooling is performed in the present invention, but the cooling temperature difference is small compared with the conventional electron coagulation, so that time and energy can be saved. The method for heating tofu of the present invention is effective not only for heating to impart sufficient hardness to the tofu, but also for heating all tofu that causes a coagulation action. For example, to defrost frozen tofu, deactivate enzymes, improve drainage of tofu, coagulate and sterilize with lactic acid bacteria, further gelatinize tofu (dough) starch, color and decolorize tofu, flavor For example, the heating method of the present invention can be widely applied.

[0010] The method for producing tofu according to claim 2 of the present invention comprises a step of promoting coagulation while adding and mixing a coagulant mainly composed of bittern to soy milk, and thereafter, the tofu produced by aging for a certain period of time. In a container provided with an electrode plate.

According to the present invention, it is possible to produce high quality bittern tofu which has a high sweetness and a high flavor and a sufficient hardness. In other words, tofu manufactured by adding and mixing a coagulant mainly composed of bittern such as magnesium chloride to soy milk is the best tofu that has the sweetness of soybeans and brings out the flavor of tofu, but it is soft and hard. It is said that it is not enough. In addition, magnesium chloride requires a high level of technology when the coagulation reaction is mixed quickly, and has a problem that handling is difficult.

However, if a coagulant mainly composed of bittern such as magnesium chloride is added to and mixed with soymilk to promote coagulation and aged for a certain period of time, soymilk is no longer said to be soymilk and a semi-coagulated tofu is formed. Therefore, when the tofu produced in the previous step is heated by energization in the container provided with the electrode plates, uniform heating can be realized because the tofu itself is used as a heat medium. In addition, since the heating is carried out rapidly, not only the power consumption can be reduced, but also the tofu can be given a sufficient hardness without substantially reducing the quality of the tofu.

Here, when a substance containing magnesium chloride (nigari) is added to soy milk, it cannot be gelled at 30 ° C. or lower. At least 30 ° to fix tofu
Temperatures higher than C are required. At 40 ° C. or higher, a coagulation reaction clearly occurs, and at 50 ° C. or higher, a rapid reaction starts immediately after the addition of a bittern-based coagulant. Therefore, the temperature of the soymilk in this case is 30 ° C or more,
Practically, the temperature is preferably 40 to 70 ° C. On the other hand, the electric heating by the electrode plate is 31-100.
In the case of heating to ° C, several minutes are sufficient. Actually, the tofu at 40 ° C. to 70 ° C. may be heated to about 75 ° C. to 85 ° C. By heating the electric current for several minutes, most of the bacteria (soil micro-bacteria) attached to soybeans and the bacteria attached to tofu can be killed. Then, according to the production method of the present invention, it is possible to produce high quality bittern tofu having soybean sweetness, the highest flavor and sufficient hardness.

Here, as the stirring means, if it is a means for promoting coagulation while adding and mixing a coagulant, one-two stirring in which a stirring plate is pulled up from the bottom portion into a container containing soymilk and stirred is used. , How to get with a knives,
There is no limitation on the stirring means, such as the double-pushing method used for producing silken tofu and the stool method used for producing cotton tofu.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In the method for producing tofu of the present embodiment, the present invention is applied to the production of bitter tofu, which is considered to be the best tofu that has the sweetness of soybean and brings out the flavor of tofu. In the following, first, the definition of bitter tofu will be described, then the apparatus used in the present embodiment will be described, and then the method for producing tofu of the present embodiment will be described. In addition,
The tofu heating method of the present invention is used in the above-mentioned tofu production process.

First, bitter tofu means magnesium chloride (purified product) or a substance containing magnesium chloride (so-called bittern as a by-product of salt production) as a coagulant, and other coagulants (smooth powder, glutanodeltalactone). Etc.) (including not only in a lump but also in the case of adding to soymilk by sorting) and soymilk and dough (for secondary processed products such as fried food). In the present invention, the content of bittern varies depending on various conditions such as temperature, but usually contains bittern of several weight% or more based on the total weight of the coagulant. Products include a wide range of products, including bitter silk tofu, bitter soft cotton tofu, ordinary cotton tofu, gummo dough, and fried (thick and thin) dough.

(Configuration of Apparatus Used in the Present Embodiment) Next, as shown in FIG. 1, the apparatus used in the present embodiment is configured such that the mold box 12 can be moved to a conveying means 2 such as a belt conveyor. The tofu producing apparatus 1 having the rotary stirring means 3 for adding and mixing the coagulant 28 to the soymilk 13 placed in the mold box 12 to promote coagulation and the energizing heating means 31 for tofu. is there.

First, the rotary stirring means 3 of the tofu manufacturing apparatus 1
As shown in FIG. 2, a polycarbonate mold box 12 is movably mounted on a belt 11 of the above-mentioned conveying means 2, and a soymilk 13 is put in the mold box 12, and a bitter is put in it. Inject the coagulant 28 as the main component and screw 1
Rotated stirring at 4. The screw 14 is provided with a rotating shaft 16, and the rotating shaft 16 is connected to a servomotor 18 by a coupling 17.

On both sides of the mold box 12, a column 1 of a predetermined length is provided.
9, 20 are erected. A guide rod 21 is attached to an upper end of one of the columns 19, and a slide portion 22 is movably fitted into the guide rod 21. Also,
A rack 23 is attached to the upper end of the other support 20, and a gear drive unit 24 is attached to the rack 23. A gear (not shown) that meshes with the rack 23 is built in the gear driving unit 24, and this gear is
Is driven to rotate. Therefore, by controlling the servomotor 25, the gear drive unit 24 can be moved up and down along the rack 23.

A horizontal plate 26 is bridged and fixed between the slide portion 22 fitted on the guide rod 21 and the gear drive portion 24 mounted on the rack 23. Are fixed. Therefore, by controlling the servomotor 25, the servomotor 18 and the screw 14 connected thereto can be raised and lowered even during rotation. That is, the guide rod 21, the slide portion 22,
The rack 23, the gear driving unit 24, the servomotor 25, and the horizontal plate 26 constitute a retracting unit for the screw 14. A control unit 27 for controlling the servomotor 18 and the servomotor 25 is disposed on the belt 11.

Next, the electric heating means 31 corresponds to FIGS.
As shown in FIG. 3, a pair of electrode plates 33 and 34 arranged in a container which is the mold box 12 and the pair of electrode plates 33 and 34 are provided.
And a power supply 35 for applying a voltage to the pair of electrode plates 33 and 34. The driving unit 32 moves the pair of electrode plates 33 and 34 up and down. The pair of electrode plates 33 and 34 are disposed opposite to each other in the mold box 12, and may be a titanium plate, an aluminum plate, a stainless steel plate, or the like. A pair of electrode plates 3 of the present embodiment
3, 34 is 348 mm wide, 175 mm long, 0.5 thick
Although it is made of a titanium plate having a size of mm, the number of the electrode plates 33 and 34 may be one or more (plural). Further, the electric heating means 31 of the present embodiment
As shown in FIG. 3, by increasing the AC frequency by the frequency converter 37, uniform and efficient heating can be realized. That is, it is known that, when the frequency is changed in the energization heating using an alternating current, a great difference occurs in the rate of temperature rise, but the energization heating means 31 of the present embodiment applies this principle. Also, dielectric heating (micro heating) may be used in combination. Although the commercial power supply (commercial power supply) is used as the power supply 35, a high frequency power supply of a power amplification type or the like may be used.

As described above, in the method for producing tofu of the present embodiment, the energizing heating means 31 is used for energizing and heating the tofu 36 itself. This is because the electric heating has lower energy loss in foods with low thermal conductivity such as solids such as tofu and kamaboko (that is, including solids, gels and sols) than liquids such as soy milk 13. This is because it is less suitable for electric heating.

(Method of Producing Tofu of the Present Embodiment)
The coagulant is added to the soymilk 13 at a temperature higher than 30 ° C. by the rotary stirring means 1 as shown in FIG. Here, the coagulant 28 is added to the soy milk 13 at a temperature higher than 30 ° C., but practically 40 ° C. to 70 ° C.
C is preferred. In addition, it is necessary to provide an aging time, and the aging time may be from immediately after the mixing of the coagulant, if it is solidified as a tofu by mixing a coagulant, from several minutes to about 2 to 3 hours. But good. That is, the normal aging time here is about 0.1 second to 180 minutes.

The coagulant 28 is mainly composed of bittern (magnesium chloride or a substance containing magnesium chloride), and may contain calcium sulfate or glutanodeltalactone (GDL) in addition to bittern. When the coagulant 28 is charged, the soymilk 13 is rotated and stirred by the screw 14 to assist the dispersion of the coagulant.

After the soymilk 13 is rotated and agitated to promote coagulation, the screw 14 is stopped, and the retraction means is used to rotate the screw 14 before the soymilk 13 is completely coagulated and raised while rotating the soymilk 13 to rotate and stir. Evacuate from. Here, since the mold box 12 is carried by the carrying means 2, the mold box 12 is carried to the next process position where the pair of (plural) electrode plates 33 and 34 are provided (see FIG. 1). .

In the next step, the electric heating means 3 shown in FIG.
1 to 31 to 100 ° C in a few minutes. Actually, the above-mentioned tofu at 40 ° C to 70 ° C is converted to 75 ° C to 8 ° C.
Heat to about 5 ° C. Such electric heating makes it possible to uniformly heat the whole tofu without heating unevenness. Therefore, the conventional boiling method, steam steaming method,
There is no problem that the tofu is easily separated from the water and becomes astringent as in the method using microwaves. In addition, by using the frequency converter 37 and increasing the AC frequency, by using dielectric heating together, it becomes possible to perform heating with more uniform heating efficiency. By such heating, it is possible to produce bittern tofu, which has been conventionally said to be soft, as bittern tofu having sufficient hardness.

Further, by heating the electric current at 60 ° C. or more, most of the bacteria (soil micro-bacteria) attached to the soybeans can be killed. That is, pasteurization 63 °
Under a temperature condition of 30 minutes at C, most pathogenic bacteria such as Shigella and pathogenic E. coli can be killed. However, heat-resistant bacteria survive and require more sterilization conditions. It is generally said that it takes 10 minutes at 80 ° C. to kill vegetative cells of sporulating bacteria. In the present embodiment, 31 to 100 ° in a few minutes in a short time
Due to heating to C, considerable vegetative cell bacteria die.

Here, in the present embodiment, the method of stirring the soybean milk 13 has been described using the rotary stirring means 3, but the present invention is applicable to any method that promotes coagulation while adding and mixing a coagulant. It is not limited. That is, soy milk 1
One-two agitation in which the stirrer is pulled up from the bottom part into the container containing 3 and agitated, a method of bringing it with a knives, a double-pulling method used for the production of silken tofu, a production of cotton tofu There is no limitation on the stirring means, such as the stool method used in the above. Further, the above-described energization heating can be used after a boiling method of immersing in hot water or a branching method of solidifying a hot water bath or an oil bath as a heat medium. However, it is desirable that there be no temperature difference between the inside and outside of the sample.

[0029]

Next, an example of actually producing bittern tofu using the method for heating and producing tofu of the present embodiment will be described. (Example 1) First, 13%
Brix (soy solid content: 11.4% wt), 12 liters of soy milk at 60 ° C., and 96 g / L of magnesium chloride-containing material were added and mixed, and the soy milk 13 was rotated and stirred. Here, mold box 1
2 is a polycarbonate mold box 12 having a length of 350 m.
m, 350 mm in width and 160 mm in depth were used.
The screw 14 has four propeller-type blades 15, and one of the blades 15 has an outer shape of 270 mmφ and a mounting angle of 45 degrees (note that the angle is not the same for the entire blade, The average inclination angle of the effective portion of the blade.Also, in the case of a structure using a plurality of blades or a structure using a plurality of stages, the average inclination angle is also used.) By this rotary stirring means 1, 160 to 80 per minute
It was continuously changed for 15 seconds until 〜0 rotation. In particular, the "closed" was carried out with great care so as not to break the bitter solidified particles and not lose their taste. That is, when the screw 14 was raised, the number of revolutions was also continuously changed according to the angle and the rising speed of the blade 15 so as not to break the approaching one. The aging time was 30 minutes, and tofu was obtained. The untreated material (Comparative Example 1) was aged for 30 minutes as it was.

Next, a pair of electrode plates 33, 34 (348 mm, 175 mm,
0.5mm size titanium plate) is installed, and 200V,
Electric heating was performed at 20A. The central temperature of tofu is 60 ° C
It took 7 minutes and 30 seconds to reach 75 ° C. The electrically heated sample (Example 1) was aged for about 22 minutes in that state, and the aging time was the same as that of the untreated sample (Comparative Example 1). Table 1 shows the results.

[0031]

[Table 1]

As is evident from Table 1, although the bitter tofu subjected to the energization treatment (Example 1) is slightly inferior in taste in comparison to the bitter tofu without the energization treatment (Comparative Example 1). As a result, it was possible to produce bittern tofu having sufficient hardness while almost maintaining the taste of bittern tofu. On the other hand, the bittern tofu in Table 1 which was not energized was tofu produced by adding a magnesium chloride-containing substance to soymilk 13 at 60 ° C. or higher, stirring the mixture, and then aging it for a certain period of time. Shows that the sweet taste of soy is the best.

Example 2 12% brix (soybean solid content 1) was placed in the same polycarbonate mold box 12 as in Example 1.
(0.5% wt), 12 liters of soymilk at 68 ° C., first, 12 g of scam powder (calcium sulfate) and 6 g of GDL were dissolved in 300 ml of water, and 96 g / L of a magnesium chloride-containing material was further added with stirring. As the stirring method, the rotary stirring means 3 was used. Four propeller-type blades having an outer diameter of 270 mmφ and a mounting angle of 45 degrees were used and continuously changed from 160 to 80 to 0 rotations per minute for 20 seconds. The coagulation temperature was adjusted to bittern. The coagulant was added with a time difference depending on each reactivity. Especially,
In order to break the bitter coagulated particles and not lose their taste, "close" was performed with great care. The aging time was 30 minutes, and tofu was obtained. Untreated materials were aged for 30 minutes.

Next, a pair of electrode plates 33, 34 (348 mm, 175 mm,
A 0.5 mm titanium plate) was installed, and electric current heating was performed at 200 V and 20 A. The central temperature of tofu is from 68 ° C to 80
It took 6 minutes to rise to ° C. The electrically heated sample (Example 2) was aged for about 24 minutes in that state, and the aging time was the same as that of the untreated sample (Comparative Example 2). Table 2 shows the results.

[0035]

[Table 2]

As is clear from Table 2, the bitter tofu subjected to the energization treatment (Example 2) has a sufficient hardness as well as the taste of the bitter tofu compared to the bitter tofu without the energization treatment (Comparative Example 2). It turns out that it is. Therefore, when a bittern tofu is produced by adding and mixing a magnesium chloride-containing substance and a shampoo powder, not only the hardness is sufficient but also the taste is higher than that of the non-energized, high quality bittern tofu. It can be seen that can be manufactured.

Further, according to the electric heating in each of the first and second embodiments, it is possible to produce bittern tofu having sufficient hardness by efficient heating without particularly increasing the accuracy of addition and mixing of the coagulant 28 and stirring. I was able to. In each of the first and second embodiments,
Was carried out at a solidification temperature of 60 ° C. and 68 ° C., which is due to the fact that bittern tofu brought in a deep box and a kitchen knife at about 60 ° C. to 68 ° C. is the highest.

As described above, the method for heating tofu of the present invention can produce bitter tofu having a sufficient hardness and high quality. However, it can give ordinary tofu a sufficient hardness and, in addition, has a solidifying effect. It can be applied to the heating of all the resulting tofu. For example, thawing frozen tofu,
The heating method of the present invention is applied to deactivate enzymes, improve drainage of tofu, sterilize, further gelatinize tofu (dough) starch, color and decolor tofu, add flavor, etc. be able to.

[0039]

According to the method for heating tofu of the present invention, the tofu is energized and heated in a container provided with an electrode plate.
Since the tofu itself is used as a heat medium, there is almost no convection of heat as in the case of conventional heating for the purpose of coagulating soymilk, so that the entire tofu can be uniformly heated, and furthermore, the heating by heating Time can be reduced. Further, there is no problem that the tofu is easily separated from the water and becomes astringent as in the conventional boiling method, steam steaming method, microwave method and the like.

On the other hand, in the method for producing tofu of the present invention, since the tofu itself is heated by using electric current as a heat medium, uniform heating can be realized. In addition, since the tofu is heated rapidly, it is possible to give the tofu a sufficient hardness without substantially reducing the quality of the tofu. Therefore, it is possible to produce a bitter tofu with sufficient hardness while almost maintaining the taste of the bitter tofu, which is considered to be the best tofu that has the sweetness of soybeans and brings out the flavor of tofu but is soft. .

Further, in the method for producing tofu of the present invention, since the time of the electric heating process can be shortened, power consumption can be reduced. Furthermore, since most of the soil micro-bacteria adhering to the soybeans and the bacteria adhering to the tofu can be killed, it is possible to provide tofu having a small number of viable bacteria and having a long shelf life.

[0042]

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of a tofu production apparatus used in the tofu production method of the present invention.

FIG. 2 is a schematic diagram showing a rotary stirring means used in the method for producing tofu of the present invention.

FIG. 3 is a schematic configuration diagram showing an electric heating unit used in the method for producing tofu of the present invention.

[Explanation of symbols]

1 tofu manufacturing device, 3 rotation stirring means, 12 type box (container), 13 soy milk, 14 screw, 15 blades, 1
8, 25 servo motor, 28 coagulant (containing magnesium chloride), 31 energizing heating means, 33, 34 electrode plate, 36 tofu

Claims (2)

[Claims] 1. A method for heating tofu, comprising electrically heating tofu in a container provided with an electrode plate. 2. A step of accelerating coagulation while adding and mixing a coagulant mainly composed of bittern to soymilk, and a step of energizing and heating the tofu produced by aging for a certain period of time in a container provided with an electrode plate. And a method for producing tofu.