JPH0154048B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to an improvement in a heating pot suitable for heating and boiling soybean soup (also referred to as bean porridge or gojiru), which is a raw material for producing tofu. It is something.

[Conventional technology and its problems]

As is widely known, the manufacturing method for tofu involves soaking soybeans in water to absorb water and swell them, then draining them and grinding them using a stone mill, etc., and pouring the resulting ground juice into a pot. Boil while adding an appropriate amount of water. After boiling, the ground juice is put into a cotton bag and compressed to separate it into soy milk and lees.The soy milk is further filtered to make soy juice, and bittern is added to this soy juice to coagulate it.
Among the above steps, the step of boiling the ground soybean juice in a heated pot removes the grassy smell of soybeans, and
This is an extremely important process for eluting proteins, oils, sugars, minerals, etc. contained in soybeans.

By the way, in the long-known tofu production method, a direct fire pot (burner heating) was used for the above-mentioned heating and boiling process of the soybean paste, but in this method,
Because it is an open flame method, there will be variations in heat distribution,
The problem was that it was not suitable for mass production because the cooking efficiency was poor and a craftsman's "intuition" was required to control the degree of ripening.

Therefore, recently, in order to enable mass production through factory production, ground soybean juice is put into a large-capacity pressure cooker equipped with a pipe that blows out live steam (direct steam). Heating pots have come into use in which live steam is sent from the outside into a pipe inside the pot, and the live steam is blown directly into the ground soup to boil it while stirring the ground soup. In this heating pot, steam is blown directly into the ground juice in the pot as a boiling heat source, so it has the advantage of reducing heat loss and greatly improving thermal efficiency.As a result, it can be expected to shorten processing time and process large quantities. are doing.

By the way, in this heating pot, steam is directly blown into the ground liquor in the pot as a heat source, but the water used for this steam is softened in advance to prevent corrosion and scale adhesion in the boiler heat exchanger. Certain agents are added to make it more effective. Therefore, when this heating pot is used, steam containing impurity additives that should not be included in the ground soybean juice is mixed into the ground soybean juice, and these additives are the umami components of the ground soybean juice. This results in a problem that the tofu becomes watery and loses its deliciousness.

In addition, the soybeans used as raw materials for tofu are harvested in the fall and used by the following fall, but the water absorption rate of fresh soybeans during processing is not the same throughout the year; It is necessary to make a significant difference in the water immersion time before grinding. Therefore, when soybean ground juice, whose water absorption rate varies depending on the season, is directly heated with live steam, the amount of condensate added to the ground water will increase due to differences in air and water temperatures that vary depending on the season. The problem is that the amount of water changes, making it difficult to maintain a constant concentration of ground juice throughout the year.

In addition, when high-pressure steam is brought into direct contact with ground juice, the stirrability of ground juice increases, but components such as soybean protein, oil, sugars, and minerals rapidly decompose or denature, resulting in so-called surface burns of the raw materials and the umami flavor. There is also the problem that there is a loss. One of the purposes of blowing high-pressure steam into this heating pot is to give the ground soup a fluid stirring effect, but considering the problems caused by blowing high-pressure steam as mentioned above, when low-pressure steam is used. Even if the problem of decomposition and denaturation of the ground juice does not occur, the stirrability is lost and it tends to become unevenly boiled, and furthermore, because the stirrability is poor, foaming becomes intense and a large amount of antifoaming agent must be mixed in. There is a problem that it must be done.

[Means for solving problems]

In order to solve the problems of the conventional heating pots for mass production as described above, the present invention has changed the heating method of blowing live steam directly into the ground soup, and has replaced the traditional manufacturing method. This method attempts to boil the ground soup using indirect heat applied from outside the pot.

Naturally, with the indirect heating method in which the ground soup is boiled using heat applied to the outside of the pot, the heat cannot be sufficiently transferred to the ground soup in the center of the pot. The problem is that it is not suitable for mass production.

Therefore, in the present invention, a heating pot is provided with a double wall in the center of the bottom, which has a heating surface on its outer periphery, and has a height such that its upper end projects above the liquid level of the ground soybean juice that is put into the heating pot. A tubular heating column is installed upright so that heat is transferred to the ground soup from the outer periphery and center of the pot, and the heating column is heated from the upper end of the stirring shaft inserted through the center of the inner tube of the heating column. By rotating a plurality of stirring blades extending toward the inner wall around the heating column, the ground soup is always boiled under appropriate stirring action, and the large-capacity pot container It is also characterized in that a sufficiently large amount of ground soup can be boiled.

A preferred type of heating pot is the well-known jacket-type heating pot, which heats the contents from the outside of the inner wall by pumping steam between double walls. The heating column to be erected may have any structure as long as it can be heated by conducting steam into the interior, similar to the peripheral wall of the pot.

Further, as the heat source for the heating pot and the central heating column, in addition to the above-mentioned indirect steam, electric heat from an electric heater may be used.

[Effect]

The ground soybean juice put into the heating pot is given a wide heat transfer area by the heat from outside the pot and the heat from the heating column located in the center of the ground soup, and the large-capacity pot has a large heat transfer area. Sufficient high heat exchange performance can be obtained in the kettle even when the ground juice is ground. In addition to expanding the heat transfer area, the stirring blades can be rotated around the heating column by the stirring shaft inserted inside the central heating column, giving sufficient stirring flow to the ground soup to prevent burning. And thermal diffusion can be performed effectively, and raw material processing with stabilized quality can be performed efficiently without requiring an antifoaming agent.

Of course, when this heating pot is used, there is no contamination of drain water containing harmful additives, which is the case when live steam is directly blown into the ground water as a raw material, so there is no reduction in the concentration of ground water or variations in the ground water concentration. Alternatively, there is no disadvantage of loss of flavor components due to additives, and the concentration of ground juice can always be kept constant as a process, so it has the advantage of being useful for producing high-quality tofu with stable quality.

〔Example〕

Next, an embodiment of the structure of the heating pot according to the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the structure of the heating pot of the present invention. It is based on the format. Inner bottom 2b and outer bottom 3b of this heating pot 1
A double-pipe heating column 5 consisting of an inner tube 6 and an outer tube 7, each coaxial, is erected at the center of the tube. The lower end of the outer tube 7 is fixed to the inner bottom 2b, and the lower end of the inner tube 6 is fixed to the outer bottom 3b, so that the jacket 4 and the inner and outer double tubes 6, 7 are connected between the inner and outer bottoms 2b, 3b.
The jacket 8 in between is arranged to communicate with the jacket 8. Moreover, this heating column 5 has an upper end at the opening 1 of the pot 1.
The ground soup is formed sufficiently long so that it is located at a position slightly lower than point A, that is, at a position that protrudes above the liquid level of the ground soup 16 put into the pot 1 as shown in FIG. is designed so that it does not come into contact with mechanical parts such as bearings in the stirring device.

A stirring shaft 11 rotated by a motor 9 and a reducer 10 provided on the lower surface of the outer bottom 3b is inserted into the inner tube 6 of the heating column 5.
1a projects above the upper end bearing portion 5a of the heating column 5. A plurality of arms 12 are branched out from the upper end 11a of the stirring shaft toward the inner side of the pot 1, and each arm 12 has a stirring blade 13 that contacts the inner circumferential surface of the inner wall 2a and an outer circumferential surface of the heating column 5. A stirring blade 14 in contact with the inner bottom 2b and a stirring blade 15 in contact with the surface of the inner bottom 2b are provided, respectively. When heating and boiling the ground soup 16, a pressurizing lid 17 is attached to the top of the pot 1, so that the amount of heat due to evaporation of water in the ground soup is not released to the outside.

FIG. 3 shows another embodiment, in which an electric heater 18 is provided on the outer surface of the inner wall 2a and inner bottom 2b in the jackets 4 and 8 of the pot 1, and a heating column 5 is provided.
Electric heaters 19 are also arranged on the inner surface of the outer tube 7, respectively, so that the pot 1 and the heating column 5 are heated by electric heat. In this case, the configuration of the stirring blade is the same as in the embodiment using steam as the heat source.

The process of boiling ground soup using a heating pot using steam as a heat source is as shown in FIG. That is, after pouring ground soup at room temperature into the heating pot 1 at room temperature, high pressure steam is introduced into the pot 1 and the heating column 5 for about 5 to 10 minutes to heat the ground soup to 80°C. After the ground soup is heated to 80°C, the steam is supplied to and cut off to the pot 1 and the heating column 5 at intervals of several minutes, and the heated state of 80 to 85°C is maintained for about 15 minutes.
By performing this heating, nutrients contained in the ground juice, especially proteins, are thermally denatured, and the grassy odor characteristic of soybeans is also removed.

After completing the heat treatment for the purpose of extracting nutrients, as a post-treatment, the amount of steam supplied to the pot 1 and the heating column 5 is increased, and this state is continued for 3 to 5 minutes to bring the ground juice to about 100°C. Rise. This treatment is aimed at preventing unevenness and sterilization, and after the predetermined temperature is reached, the steam supply is stopped and the boiling treatment is completed.

〔effect〕

The heating pot according to the present invention has a heating column that also serves as a support for the stirring blade shaft erected in the center of the bottom, and the surrounding wall and the inside of the pot are connected to the ground soybean juice as a raw material for tofu that is put into the pot. Since the heat is transferred from the center, the middle part 16a of the ground soup 16 between the heating surfaces of the inner wall 2a of the pot and the heating column 5, where the heating surface is farthest, has the heating column 5. The distance is reduced to 1/4 of the diameter compared to conventional pots that do not have the same diameter. Therefore, the heat transfer efficiency is improved, and even when using an external heat source heating oven for heating ground soup in a large-capacity oven, the same amount of heat can be obtained as with a conventional steam direct injection heating oven. Therefore, it can be adopted as a device suitable for mass production.

Moreover, even if the heating pot of the present invention uses steam as a heat source, unlike conventional heating pots, there is no need to blow steam directly into the ground juice, so product deterioration due to mixing of steam water containing additives. Eliminate the
This method has the advantage of making it much easier to control the concentration of the ground soup and producing high-quality tofu with stable quality.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the configuration of a heating pot according to the present invention, and FIG. 2 is a cross-sectional view of the pot shown in FIG. 1 with the stirring blade removed, showing the relationship between the heating surface and the ground liquid.
FIG. 3 is a sectional view of a pot according to another embodiment, FIG. 4 is a plan view of the heating pot, and FIG. 5 is a process explanatory diagram of a processing method. 1: heating pot, 2a: inner wall, 2b: inner bottom, 3a:
Outer wall, 3b: Outer bottom, 4: Jacket, 5: Heating column, 6: Inner tube, 7: Outer tube, 8: Jacket, 9:
Motor, 10: Reducer, 11: Stirring shaft, 12:
Arm, 13, 14, 15: stirring blade, 16: ground juice, 17: pressure lid, 18, 19: electric heater.

Claims (1)

[Claims] 1. A heating surface on the outer periphery is provided at the center of the bottom of the heating pot and has a height such that the upper end projects above the liquid level of the ground soybean juice to be put into the heating pot. The tofu is characterized by having a double-tube heating column erected therein, and a plurality of stirring blades extending from the upper end of a stirring shaft inserted into the center of the inner tube of the heating column toward the inner wall of the heating pot. Heating pot for raw materials. 2. The heating pot is a jacket-type heating pot that uses indirect steam heat as a heat source, and the steam for the heat source of the heating pot is conducted between the outer tube and the inner tube of the double-tube heating column. A heating pot for raw materials for tofu according to claim 1. 3. The heating pot for tofu raw materials according to claim 1, wherein electric heaters for heat sources are arranged on the outer periphery of the heating pot and on the inner periphery of the outer tube of the central heating column.