KR19990059052A - Manufacturing method of tofu by ohmic heating - Google Patents

Abstract

The present invention relates to a method for producing tofu with improved yield and improved texture by employing an ohmic heating step as a heating method for producing tofu. The manufacturing process of tofu by ohmic heating of the present invention is a step of immersing soybeans in 5 to 15 times of water and left at 15 to 30 ℃ for 10 to 15 hours, then grinding for 3 to 6 minutes to obtain soy juice, Put the obtained biscuits into the ohmic heating device, the AC electric field is added for 15 to 25 minutes to heat to 85 to 95 ℃, and maintained for 5 to 20 minutes, the heated biscuits using a juicer 5 A step of separating the biji by pressing at a pressure of from 10kg / cm ² to obtain a heated soymilk, while maintaining the heating soymilk obtained in the past at a temperature range of 60 to 80 ℃, stirring with the addition of a coagulant, 10 to 40 minutes The process of left to coagulate and the process of compressing the coagulated soy milk at the pressure of 15-25 g / cm <^2> for 45 to 75 minutes in the electricity. When the tofu is prepared by the method of the present invention, the production yield is increased by 10% or more compared with the conventional method, and by adjusting the alternating frequency, the solid content in the tofu can be adjusted to prepare tofu having a texture suitable for taste.

Description

Manufacturing method of tofu by ohmic heating

The present invention relates to a method for producing tofu by ohmic blade heating. More specifically, the present invention relates to a method of manufacturing tofu with improved yield and texture by employing an ohmic heating step as a heating method for manufacturing tofu.

Tofu, which is formed by extracting and coagulating water-soluble protein and solids from soybeans containing a large amount of nutrients such as protein and fat, heats the soymilk obtained by crushing soybeans called water, and then cools and stirs while adding a coagulant. It has been manufactured by the process. At this time, the obtained soy milk should be rapidly raised in a short time, such heat treatment, such as to improve the nutritional quality of the tofu finally produced and to reduce the soybean odor, such as to improve the quality of the tofu. In addition, by heat treatment, the components in the soy protein are denatured, such as agglomeration or polymer formation, and the subsequent solidification step is possible by such modification. On the other hand, agglomeration of the soy protein component or polymer formation by heat treatment is caused by the exchange reaction of the -SH group in the protein component, and when heated to a suitable temperature for a suitable time, the -SH group of the protein component is reduced and solids are formed. Therefore, the best quality tofu is produced only by heating for a predetermined period at the optimum heating temperature.

In general, a heat exchanger has been mainly used for such heat treatment. However, since the heating by the heat exchanger is an indirect heating method for the heat transfer to be conducted by conduction, it takes a considerable time to heat, and also wasted energy because the heat transfer is not made completely in the heat transfer process. In addition, in the case of using a conventional heat exchanger, the heating process is not precisely controlled, and often overheating occurs, thereby promoting the metal adsorption reaction of the protein contained in the soybean, thereby forming a large scale. In many cases, operations were stopped to eliminate this.

Therefore, during the tofu manufacturing process, the heating process, which has the greatest influence on the quality of the tofu and has a meaning to determine the efficiency of the subsequent manufacturing process, is performed for a certain time at the correct temperature, thereby improving the manufacturing process and manufacturing accordingly. Development of a method to improve yield and quality was urgently needed.

Thus, the inventors of the present invention, in order to develop a method for producing a high-yield tofu with improved texture, as a result of diligent research efforts, the tofu produced by coagulating the heated soy milk obtained by heating the soy juice using an Ohmick heating device In this case, it was confirmed that the water-retaining ability and the gel-forming ability were improved to produce tofu with high texture, and thus, the present invention was completed.

After all, an object of the present invention is to provide a method that can be produced in a high yield by adopting the ohmic heating method to improve the feel of texture.

1 is a diagram showing a schematic structure of an ohmic heating device according to an embodiment of the present invention.

The method for producing tofu by ohmic heating of the present invention is characterized in that the soybean obtained by grinding the beans is put into an ohmic heating device and heated by applying an alternating electric field.

Hereinafter, the ohmic heating device used in the manufacturing method of tofu by ohmic heating of the present invention will be described with reference to the accompanying drawings.

1 is a schematic view of an ohmic heating apparatus used in the manufacturing method of tofu by ohmic heating of the present invention, the ohmic heating apparatus of the present invention comprises an electrode (1), a reaction vessel (2), a stirrer (3), It includes a constant temperature water bath (4), a current regulator (5) and a power regulator (6). A power regulator (Thyristor Power Regulator, 6) connected to the commercial power supply a certain amount of current to the current regulator (5), the current controlled by the current regulator is transmitted to the electrode (1) to the juice in the reaction vessel (2) Will be heated. Subsequently, the heated bile is cooled by cold water supplied to the constant temperature water tank 4, and stirring is performed by the stirrer 3 in the solidification process. In this case, in order to prevent corrosion of the electrode, the electrode is made of stainless steel or titanium, and a current controller uses a PID (proportional integrated differentiation) controller.

Hereinafter, the manufacturing method of tofu by ohmic heating of the present invention will be described in detail by dividing the process.

Step 1 : Separation of Soy Juice

Soybeans were soaked in 5 to 15 times, most preferably about 10 times of water and left at 15 to 30 ° C, most preferably at about 25 ° C for 10 to 15 hours, most preferably about 12 hours, and then 3 Crushed to 6 minutes, most preferably about 4 minutes to obtain the juice.

Second Process : Ohmic Heating

The bile obtained from the electricity was put into the aforementioned ohmic heater, and an alternating electric field was added for 15 to 25 minutes, most preferably for about 20 minutes, and heated to 85 to 95 ° C, most preferably about 90 ° C, and 5 to 20 Minutes, most preferably about 10 minutes. At this time, the alternating electric field is applied at a frequency of 50 to 5,000 V / m and a frequency of 10 to 20,000 Hz.

Third Process : Crimping

The soybean heated in the past is pressed using a juicer at a pressure of 5 to 15 kg / cm ² , most preferably about 10 kg / cm ² to separate the sesame and obtain heated soymilk.

4th process : solidification

The heated soymilk obtained in the former is kept at a temperature of 60 to 80 ° C., most preferably about 75 ° C., while a coagulant is added, stirred, and left to stand for 10 to 40 minutes to coagulate. At this time, the coagulant uses calcium sulfate of 20 to 30mM, preferably 25 to 27mM.

5th process : shaping of tofu

The curd soymilk is pressed by pressing at a pressure of 15 to 25 g / cm ² , most preferably about 20 g / cm ² , for 45 to 75 minutes and most preferably about 60 minutes to form the tofu.

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are only for illustrating the present invention in more detail, it will be apparent to those skilled in the art that the scope of the present invention is not limited to these examples.

Example 1 Change in Yield of Tofu Prepared with Different Coagulant Concentration

100 g of the soybeans from which the foreign substances were removed were immersed in 10 times of water, and left at 25 ° C. for 12 hours, and then ground for 4 minutes to obtain a bile, and pressed to a constant pressure of 10 kg / cm ² to separate soy milk. The soymilk was then heated to 90 ° C. in an ohmic heater with 2,000 V / m, 60 Hz alternating electric field for 20 minutes, held for 10 minutes, and then cooled to 75 ° C. Then, to confirm the effect of the coagulant concentration on the yield of tofu, calcium sulfate was added at three concentrations of 25, 26 and 27 mM, and left for 30 minutes, and pressed to 60 minutes at a pressure of 20 g / cm ² . Prepared. The weight and solids content of the tofu thus prepared were measured and the results were calculated to determine a production yield, which is a recovery rate of solids prepared from soybean, and the results are shown in Table 1 below.

Comparative Example 1 :

In order to compare the conventional heating method and the manufacturing method of tofu by ohmic heating of the present invention, tofu was prepared in the same manner as in Example 1 except that the soymilk was heated using a heat exchanger. Subsequently, the weight and solids content of the prepared tofu were measured and the results thereof were calculated to determine a manufacturing yield, which is a recovery rate of solids prepared from soybean, and the results are shown in Table 1 below.

Changes in Yield of Tofu Prepared by Concentration of Coagulant Coagulant concentration Tofu weight Solid content Manufacture yield Example 1 Comparative Example 1 Example 1 Comparative Example 1 Example 1 Comparative Example 1 25mM 51.7 g 37.72 g 13.56% 14.47% 53.92% 42% 26mM 53.3 g 36.83 g 13.32% 14.5% 54.62% 41.08% 27mM 52.39 g 34.3 g 13.02% 16.42% 52.46% 43.31%

As shown in Table 1, the tofu of Example 1 prepared by the ohmic heat treatment and cold crushing method increased the weight of the tofu to an average of 44.8% compared to the tofu of Comparative Example 1 prepared by the conventional method. In addition, the absolute solid content is also increased, the production yield was found to increase to 27.5% on average, it was confirmed that the manufacturing method of tofu by Ohmick heat treatment is superior to the conventional method. In addition, when the coagulant was treated at a concentration of 26 mM, the production yield showed the maximum value.

Example 2 Change in Yield of Tofu Prepared with Different AC Frequency

Tofu was prepared in the same manner as in Example 1 except that the alternating frequency was set to three conditions of 40, 50, and 60 Hz, and the concentration of calcium sulfate was 25 mM as the coagulant. Thus, by measuring the weight and solids content of the tofu thus prepared and calculating the results, it was determined the production yield that is the recovery of solids prepared from soybeans, the results are shown in Table 2 below.

Effect of AC Frequency on Yield Production Item Frequency (Hz) 40 80 120 Tofu Weight (g) 23.2 35.9 43.3 Solid content (g) 19.2 12.8 11.8 Manufacture yield 49.7 51.2 57.1

As shown in Table 2, as the alternating current frequency was increased, the weight and manufacturing yield of the tofu produced were also increased, but the solid content tended to decrease. It was confirmed that it was prepared.

Example 3 Preparation of Tofu by Onbiz Method

100 g of soybeans from which foreign substances were removed were immersed in 10 times of water, left at 25 ° C. for 12 hours, and then ground for 4 minutes to obtain soy juice. 20 minutes were added and heated to 90 ° C. and maintained for 10 minutes. Then, the heated soybeans were pressed at a constant pressure of 10 kg / cm ² using a juicer to separate the sesame and to obtain heated soymilk. Subsequently, the heated soy milk was maintained at a temperature of 75 ° C., calcium sulfate was added at a concentration of 25 mM, left for 30 minutes, and pressed to 60 minutes at a pressure of 20 g / cm ² to prepare tofu. The weight and solids content of the tofu thus prepared were measured, and the result was calculated to determine a manufacturing yield, which is a recovery rate of solids prepared from soybean, and the results are shown in Table 3 below. In addition, the numerical values described in Example 1 and Comparative Example 1 of the following Table 3 are the results when the solidification was made by adding 25 mM calcium sulfate in the results of Example 1 and Comparative Example 1.

Effect of Onbiz Method on Yield of Tofu Item Example 1 Example 3 Comparative Example 1 Tofu Weight (g) 51.70 53.1 37.72 Solid content (%) 13.56 14.2 14.47 Manufacture yield (%) 42.00 55.3 42.00

Among the manufacturing methods of tofu by ohmic heating method, the effect of conventional cold soy milk separating and heating of soy milk and on-busy method of obtaining soy milk while heating and separating juice by extracting juice first to confirm the effect on the yield of tofu In order to prepare the tofu by the on busy method and compare the result with the results of Example 1 and Comparative Example 1 produced by the cold busy method, it was found that the manufacturing yield of tofu increased by 13.3%. It was confirmed that the preparation of tofu is a more effective method.

As described and demonstrated in detail above, the present invention provides a method of manufacturing tofu with improved yield and texture by employing an ohmic heating process as a heating method for manufacturing tofu. When the tofu is prepared by the method of the present invention, the production yield is increased by 10% or more compared with the conventional method, and by adjusting the alternating frequency, the solid content of the tofu can be adjusted to prepare tofu having a texture suitable for taste. .

Claims (4)

Soaking the soybeans in 5 to 15 times of water for 10 to 15 hours at 15 to 30 ° C., and then grinding for 3 to 6 minutes to obtain bile; Putting the soybean obtained in the electricity into an ohmic heater, applying an alternating electric field for 15 to 25 minutes, heating to 85 to 95 ° C, and maintaining for 5 to 20 minutes; Pressing soybean juice heated in the past at a pressure of 5 to 10 kg / cm ² using a juicer to separate the sebum and obtaining heated soymilk; A step of solidifying by adding a coagulant while stirring the heated soymilk obtained in the former at a temperature range of 60 to 80 ° C, and leaving it to stand for 10 to 40 minutes; And, A method for producing tofu by ohmic heating, comprising the step of pressing the coagulated soymilk at a pressure of 15 to 25 g / cm ² for 45 to 75 minutes. The method of claim 1, The magnitude of the alternating current electric field is 50 to 5,000 V / m, and the frequency of the alternating current is 10 to 20,000 Hz. Method of manufacturing tofu by ohmic heating. The method of claim 1, The coagulant is characterized in that using calcium sulfate of 20 to 30mM Method of manufacturing tofu by ohmic heating. The method of claim 1, Ohmic heating device is characterized in that it comprises a constant temperature water bath, reaction vessel, electrode, current regulator, power regulator and agitator Method of manufacturing tofu by ohmic heating.