Preparation method of tender bean curd
By using gypsum and gluconolactone as coagulant in the traditional preparation method of tender tofu, and adding apple juice to cooked soy milk for ice water bath treatment, the problems of poor taste and low yield in the traditional method are solved, and the problem of tender tofu is not good. High moisture content and high quality tender tofu preparation.
Patent Information
- Application Number
- CN202411825758.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-11
- Publication Date
- 2025-02-14
AI Technical Summary
The traditional tender tofu preparation method is not tender and smooth enough, the yield is not high, and the new coagulant has a complex process, high cost or unsatisfactory effect.
Gypsum and gluconolactone were used as coagulation agents, apple juice was added to cooked soy milk and treated in an ice-water bath. Then heated and mixed with coagulation agent, and let it stand to form flocculent tofu and set.
It improves the moisture content and sensory quality of tender tofu, significantly improves the yield, and achieves the effect of improving the quality and yield of tender tofu at a simple and low cost.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of food preparation, and in particular relates to a method for preparing soft tofu. Background Art
[0002] Soft tofu generally refers to southern tofu, also known as gypsum tofu, which is a delicacy made from soybeans as the main raw material. It has a soft and delicate texture, is high in protein and low in fat, and has the effects of lowering blood pressure, blood lipids and cholesterol. It is a delicacy that can be eaten raw or cooked, and is suitable for both young and old. The traditional method for preparing soft tofu uses gypsum or gypsum and lactone as a coagulant, soaks dry soybeans and grinds them into raw soybean milk, and then prepares the raw soybean milk into mature soybean milk. After cooling to a suitable temperature, gypsum or gypsum and lactone are added to prepare flocculent tofu, and then pressed and shaped to prepare it, but it often has a not tender and smooth taste and low yield. At present, the yield and quality of soft tofu are mostly improved by adjusting the type of coagulant, but new coagulants such as fungus fermentation products and complex enzymes often have complex preparation processes, high costs or unsatisfactory effects. Therefore, there is an urgent need for a method that can improve the quality and yield of soft tofu simply and at low cost based on the types of traditional coagulants. Summary of the invention
[0003] In view of this, the object of the present invention is to provide a method for preparing soft tofu, which can achieve the effect of improving the yield and quality of soft tofu in a simple and low-cost manner based on gypsum and gluconolactone as coagulants.
[0004] The invention provides a method for preparing soft tofu, comprising the following steps: when the temperature of cooked soy milk is adjusted to 55-65 DEG C, apple juice is added and kept warm and allowed to stand, then the mixture is placed in an ice water bath and allowed to stand, then the mixture is heated to 70-80 DEG C, mixed with gypsum and gluconolactone, allowed to stand to form flocculent tofu curd, and the soft tofu is obtained by shaping.
[0005] Preferably, the concentration of the cooked soy milk is 1:8-10 based on the mass ratio of dry soybeans to water.
[0006] Preferably, the ratio of the apple juice to the cooked soy milk is 1.5-2.5 mL:100 g.
[0007] Preferably, the heat preservation and standing time is 8 to 12 minutes.
[0008] Preferably, the standing time of the ice water bath is 30 to 40 minutes.
[0009] Preferably, the mass ratio of the total amount of gypsum and gluconolactone added to the cooked soy milk is (1-2): (900-1100).
[0010] Preferably, the mass ratio of gypsum to gluconolactone is 1 to 3:1.
[0011] Preferably, the standing time for forming the flocculent bean curd is 10 to 20 minutes.
[0012] Preferably, the shaping is performed by placing the cloth in a cloth wrapping mold and letting it stand for 25 to 35 minutes.
[0013] The invention also provides soft tofu prepared by the preparation method.
[0014] Beneficial effects of the present invention:
[0015] The method for preparing soft tofu provided by the present invention adopts traditional coagulants gypsum and gluconolactone, adds apple juice to cooked soy milk at a specific temperature and then performs an ice water bath, so that the obtained soy milk can be better coagulated under the action of gypsum and gluconolactone, improves the water content and sensory quality of the prepared soft tofu, and at the same time, significantly improves the yield of soft tofu, achieving the effect of simply and at low cost to improve the yield and quality of soft tofu. DETAILED DESCRIPTION
[0016] The invention provides a method for preparing soft tofu, comprising the following steps:
[0017] When the temperature of the cooked soy milk is adjusted to 55-65°C, apple juice is added and kept warm and allowed to stand, then placed in an ice water bath and allowed to stand, then heated to 70-80°C, mixed with gypsum and gluconolactone, allowed to stand to form flocculent tofu pudding, and shaped to obtain soft tofu.
[0018] In the present invention, there is no special limitation on the source of the cooked soy milk, and either homemade or commercially available products can be used. The homemade method preferably includes: using plump, mold-free and worm-free dry soybeans, washing and soaking them in water for pulping, the mass of the added water is preferably 3 to 5 times the mass of the dry soybeans, and in one embodiment, 3 times, 4 times or 5 times the amount of water can be selected; the soaking time is preferably 6 to 8 hours, and in one embodiment, 6 hours, 6.5 hours, 7 hours, 7.5 hours or 8 hours can be selected; the present invention does not have special limitations on the pulping method, and conventional pulping methods in the field can be used, preferably soybean milk machine pulping or wall breaking machine pulping, the pulping times are preferably 3 to 5 times, and in one embodiment, 3 times, 4 times or 5 times can be selected to obtain raw soybean milk; the raw soybean milk is filtered and then completely boiled to prepare cooked soybean milk; the complete boiling is preferably maintained for 3 to 5 minutes after boiling to 100°C, such as 3 minutes, 4 minutes or 5 minutes. The concentration of the cooked soy milk is preferably 1:8-10 in terms of the mass ratio of dry soybeans to water. In one embodiment, 1:8, 1:8.5, 1:9, 1:9.5 or 1:10 can be selected.
[0019] In the present invention, after the cooked soy milk is purchased or prepared, the temperature is adjusted to 55-65°C, and apple juice is added to keep warm and stand. In one embodiment, the temperature can be 55°C, 58°C, 60°C, 62°C or 65°C; the apple juice is obtained by washing and core-removing apples and then squeezing the juice. The present invention does not specifically limit the method of squeezing the juice. In one embodiment, a juicer or a wall-breaking machine can be selected to squeeze the juice and filter it. When squeezing the juice, preferably, the apples are cut into small pieces, and water is added in a mass ratio of apples to water of 1:0.8-1 (such as 1:0.8, 1:0.9 or 1:1), and then the juice is squeezed and filtered to obtain the apple juice; the amount of the apple juice added is the same as the amount of the apple juice added. The ratio of cooked soy milk is preferably 1.5-2.5 mL: 100 g. In one embodiment, 1.5 mL: 100 g, 1.8 mL: 100 g, 2.0 mL: 100 g, 2.2 mL: 100 g or 2.5 mL: 100 g can be selected; the heat preservation and standing time is preferably 8-12 min. In one embodiment, 8 min, 9 min, 10 min, 11 min or 12 min can be selected; and then put into an ice water bath and stand, the standing time is preferably 30-40 min. In one embodiment, 30 min, 32 min, 35 min, 38 min or 40 min can be selected. The present invention can make the cooked soy milk react better with gypsum and gluconolactone by adding apple juice to the cooked soy milk and then treating it in an ice water bath, so as to make the soy milk coagulate better, thereby improving the quality and yield of the prepared soft tofu.
[0020] In the present invention, the cooked soy milk is placed in an ice water bath and then mixed with a coagulant, that is, the cooked soy milk is heated to 70-80° C., and in one embodiment, the temperature can be selected to be 70° C., 72° C., 75° C., 78° C. or 80° C.; and then mixed with gypsum and gluconolactone, and the mixing is preferably to add the cooked soy milk into a container containing gypsum and gluconolactone, and stir while adding so that the coagulant and the cooked soy milk are fully mixed; the total amount of the gypsum and gluconolactone added is equal to the cooked soy milk. The mass ratio of gypsum to gluconolactone is preferably (1-2):(900-1100). In one embodiment, 1:900, 1:1000, 1:1100, 1.5:900, 1.5:1000, 1.5:1100, 2:900, 2:1000 or 2:1100 can be selected. The mass ratio of gypsum to gluconolactone is preferably 1-3:1. In one embodiment, 1:1, 1.5:1, 2:1, 2.5:1 or 3:1 can be selected.
[0021] In the present invention, cooked soy milk is evenly mixed with gypsum and gluconolactone and then allowed to stand to form flocculent tofu curd, and the standing time is preferably 10 to 20 minutes. In one embodiment, 10 minutes, 13 minutes, 15 minutes, 17 minutes or 20 minutes can be selected. The flocculent tofu curd is shaped to obtain tender tofu, and the shaping is to place the flocculent tofu curd in a mold containing a wrapping cloth, press a heavy object on it and let it stand to form. The wrapping cloth is a filter cloth that can hold and wrap the flocculent tofu curd. The standing time is preferably 25 to 35 minutes. In one embodiment, 25 minutes, 28 minutes, 30 minutes, 32 minutes or 35 minutes can be selected.
[0022] The invention also provides soft bean curd prepared by the preparation method. The soft bean curd has milky white color, strong bean flavor, complete block shape, fine texture, high water content, and soft, elastic and delicious taste.
[0023] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.
[0024] In the following embodiments, unless otherwise specified, all of them are conventional methods.
[0025] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.
[0026] The apple juice used in the following embodiments and comparative examples is homemade, and the preparation method is as follows: Fuji apples purchased from the market are washed, cored, and cut into small pieces, water is added in a ratio of 1:1 between the cored apples and water, and the pieces are put into a wall breaking machine with the fruit and vegetable juice function selected and filtered.
[0027] The pulping described in the following embodiments and comparative examples is all prepared by using a wall-breaking machine with the soymilk function selected.
[0028] Example 1
[0029] 200 g of dry soybeans that are plump, free of mold and worms are selected, and after washing, water is added to cover the soybeans by 4 times, and soaked for 7 hours; the beans are then taken out and 1800 g of water is added to make pulp 4 times to obtain raw soybean milk, which is filtered and completely boiled, and when the temperature drops to 60°C, 40 mL of apple juice is added and stirred evenly, and the mixture is kept warm and allowed to stand for 10 minutes, and then placed in an ice water bath and allowed to stand for 35 minutes, and then heated to 75°C, and quickly poured into a container containing 2 g of gypsum and 1 g of gluconolactone, stirring while pouring to mix evenly, and forming flocculent tofu pudding after standing for 15 minutes, and then the tofu pudding is placed in a mold equipped with a cloth, pressed with a heavy object, and allowed to stand for 30 minutes to be shaped to obtain soft tofu.
[0030] Example 2
[0031] 200 g of dry soybeans that are plump, free of mold and worms are selected, and after washing, water is added to cover the soybeans by 3 times, and soaked for 6 hours; then the beans are taken out and 1600 g of water is added to make pulp 3 times to obtain raw soybean milk, which is filtered and completely boiled, and when the temperature drops to 65°C, 27 mL of apple juice is added and stirred evenly, and the mixture is kept warm and allowed to stand for 8 minutes, and then placed in an ice water bath and allowed to stand for 40 minutes, and then heated to 70°C, and quickly poured into a container containing 1.5 g of gypsum and 0.5 g of gluconolactone, and stirred while pouring to mix evenly, and flocculent tofu pudding is formed after standing for 10 minutes, and then the tofu pudding is placed in a mold equipped with a cloth, pressed with a heavy object, and allowed to stand for 25 minutes to be shaped to obtain soft tofu.
[0032] Example 3
[0033] 200 g of dry soybeans that are plump, free of mold and worms are selected, and after washing, water is added that is 5 times the amount of the soybeans and soaked for 8 hours; the beans are then taken out and slurried with 2000 g of water for 5 times to obtain raw soybean milk, which is filtered and completely boiled, and when the temperature drops to 55°C, 55 mL of apple juice is added and stirred evenly, and the mixture is kept warm and allowed to stand for 12 minutes, and then placed in an ice water bath and allowed to stand for 30 minutes, and then heated to 80°C, and quickly poured into a container containing 2 g of gypsum and 2 g of gluconolactone, stirring while pouring to mix evenly, and forming flocculent tofu pudding after standing for 20 minutes, and then the tofu pudding is placed in a mold equipped with a cloth, pressed with a heavy object, and allowed to stand for 35 minutes to be shaped to obtain soft tofu.
[0034] Comparative Example 1
[0035] Screen 200g of dry soybeans that are plump, free of mold and worms, wash them, add water that is 4 times the size of the soybeans and soak them for 7h; then take out the beans and add 1800g of water to make pulp 4 times to obtain raw soybean milk, filter and boil the raw soybean milk completely, add 40mL of apple juice when the temperature drops to 60°C, stir evenly, keep warm and let stand for 10min, then heat to 75°C, quickly pour into a container containing 2g of gypsum and 1g of gluconolactone, stir while pouring to mix evenly, let stand for 15min to form flocculent tofu pudding, then put the tofu pudding into a mold equipped with a cloth, press with a heavy object and let stand for 30min to obtain soft tofu.
[0036] Comparative Example 2
[0037] 200 g of dry soybeans that are plump, free of mold and worms are selected, and after washing, water is added to cover the soybeans by 4 times, and soaked for 7 hours; then the beans are taken out and 1800 g of water is added to make pulp 4 times to obtain raw soybean milk, which is filtered and completely boiled, then placed in an ice water bath and allowed to stand for 35 minutes, then heated to 75°C, and quickly poured into a container containing 2 g of gypsum and 1 g of gluconolactone, stirring while pouring to mix evenly, and forming flocculent tofu pudding after standing for 15 minutes, and then the tofu pudding is placed in a mold equipped with a cloth, pressed with a heavy object, and allowed to stand for 30 minutes to be shaped to obtain soft tofu.
[0038] Comparative Example 3
[0039] 200 g of dry soybeans that are plump, free of mold and worms are selected, and after washing, water is added to cover the soybeans by 4 times, and soaked for 7 hours; then the beans are taken out and 1800 g of water is added to make pulp 4 times to obtain raw soybean milk, which is filtered and completely boiled, then placed in an ice water bath and allowed to stand for 35 minutes, then heated to 75°C, and quickly poured into a container containing 2 g of gypsum, 1 g of gluconolactone and 40 mL of apple juice, stirring while pouring to mix evenly, and forming flocculent tofu pudding after standing for 15 minutes, and then the tofu pudding is placed in a mold equipped with a cloth, pressed with a heavy object, and allowed to stand for 30 minutes to be shaped to obtain soft tofu.
[0040] Comparative Example 4
[0041] 200 g of dry soybeans that are plump, free of mold and worms are selected, and after washing, water is added to cover the soybeans by 4 times, and soaked for 7 hours; then the beans are taken out and 1800 g of water is added to make pulp 4 times to obtain raw soybean milk, which is filtered and completely boiled, and when the temperature drops to 75°C, it is quickly poured into a container containing 2 g of gypsum and 1 g of gluconolactone, and stirred while pouring to mix evenly, and flocculent tofu curd is formed after standing for 15 minutes, and then the tofu curd is put into a mold equipped with a cloth, pressed with a heavy object, and allowed to stand for 30 minutes before being shaped to obtain soft tofu.
[0042] Comparative Example 5
[0043] 200 g of dry soybeans that are plump, free of mold and worms are selected, and after washing, water is added to cover the soybeans by 4 times, and soaked for 7 hours; the beans are then taken out and 1800 g of water is added to make pulp 4 times to obtain raw soybean milk, which is filtered and completely boiled, and when the temperature drops to 60°C, 40 mL of apple juice is added and stirred evenly, and the mixture is kept warm and allowed to stand for 10 minutes, and then placed in an ice water bath and allowed to stand for 35 minutes, and then heated to 75°C, and quickly poured into a container containing 4 g of gypsum and 1 g of gluconolactone, stirring while pouring to mix evenly, and forming flocculent tofu pudding after standing for 15 minutes, and then the tofu pudding is placed in a mold equipped with a cloth, pressed with a heavy object, and allowed to stand for 30 minutes to be shaped to obtain soft tofu.
[0044] Comparative Example 6
[0045] 200 g of dry soybeans that are plump, free of mold and worms are selected, and after washing, water is added to cover the soybeans by 4 times, and soaked for 7 hours; the beans are then taken out and 1800 g of water is added to make pulp 4 times to obtain raw soybean milk, which is filtered and completely boiled, and when the temperature drops to 70°C, 40 mL of apple juice is added and stirred evenly, and the mixture is kept warm and allowed to stand for 10 minutes, and then placed in an ice water bath and allowed to stand for 35 minutes, and then heated to 75°C, and quickly poured into a container containing 2 g of gypsum and 1 g of gluconolactone, stirring while pouring to mix evenly, and forming flocculent tofu pudding after standing for 15 minutes, and then the tofu pudding is placed in a mold equipped with a cloth, pressed with a heavy object, and allowed to stand for 30 minutes to be shaped to obtain soft tofu.
[0046] Comparative Example 7
[0047] 200 g of dry soybeans that are plump, free of mold and worms are selected, and after washing, water is added to cover the soybeans by 4 times, and soaked for 7 hours; the beans are then taken out and 1800 g of water is added to make pulp 4 times to obtain raw soybean milk, which is filtered and completely boiled, and when the temperature drops to 60°C, 20 mL of apple juice is added and stirred evenly, and the mixture is kept warm and allowed to stand for 10 minutes, and then placed in an ice water bath and allowed to stand for 35 minutes, and then heated to 75°C, and quickly poured into a container containing 2 g of gypsum and 1 g of gluconolactone, stirring while pouring to mix evenly, and forming flocculent tofu pudding after standing for 15 minutes, and then the tofu pudding is placed in a mold equipped with a cloth, pressed with a heavy object, and allowed to stand for 30 minutes to be shaped to obtain soft tofu.
[0048] Comparative Example 8
[0049] 200 g of dry soybeans that are plump, free of mold and worms are selected, and after washing, water is added to cover the soybeans by 4 times, and soaked for 7 hours; the beans are then taken out and 1800 g of water is added to make pulp 4 times to obtain raw soybean milk, which is filtered and completely boiled, and when the temperature drops to 60°C, 40 mL of apple juice is added and stirred evenly, and the mixture is kept warm and allowed to stand for 10 minutes, and then placed in an ice water bath and allowed to stand for 20 minutes, and then heated to 75°C, and quickly poured into a container containing 2 g of gypsum and 1 g of gluconolactone, stirring while pouring to mix evenly, and forming flocculent tofu pudding after standing for 15 minutes, and then the tofu pudding is placed in a mold equipped with a cloth, pressed with a heavy object, and allowed to stand for 30 minutes to be shaped to obtain soft tofu.
[0050] Test Example 1
[0051] Sensory evaluation of soft tofu
[0052] A sensory evaluation was conducted on the tender tofu prepared in Examples 1 to 3 and Comparative Examples 1 to 8, and 9 members were selected to form a sensory evaluation panel, aged between 25 and 35 years old, all of whom were healthy and had no underlying diseases that affect their sense of taste, smell, and vision, including 4 males and 5 females. The evaluation criteria include color: milky white, not too yellow or too white or with other mixed colors; smell: strong bean flavor, not sour; tissue state: complete block shape, fine texture; taste: tender, soft and elastic, and delicious. Each item was scored on a 10-point scale, with the higher the score, the better the sensory quality. The evaluation team removed the lowest score and the highest score for each item and took the average to obtain the final score, with a total score of 40 points. The results are shown in Table 1:
[0053] Table 1 Sensory evaluation results of soft tofu
[0054]
[0055]
[0056] It can be seen from the results in Table 1 that the sensory quality of soft tofu can be improved by first adding apple juice to cooked soy milk and letting it stand and then treating it in an ice water bath. The quality of soft tofu obtained by not adding apple juice or not treating it in an ice water bath and adjusting the order will decrease to varying degrees, and the impact on texture and taste is greater than the impact on color and smell. At the same time, by comparing the results of Example 1 and Comparative Example 5, it can be seen that adjusting the amount and proportion of coagulant will also lead to a decrease in the sensory quality of soft tofu. By comparing the results of Example 1 and Comparative Examples 6 to 7, it can be seen that the temperature and amount of apple juice added and the time of ice water bath will affect the taste of soft tofu, and the temperature of apple juice addition has a greater impact.
[0057] Test Example 2
[0058] Determination of water content and yield of soft tofu
[0059] The moisture content and yield of the soft tofu prepared in Examples 1 to 3 and Comparative Examples 1 to 8 were measured. The moisture content was measured according to the method specified in GB / T 5009.3, and the yield was calculated according to the mass percentage of the soft tofu prepared to the mass percentage of the dry soybeans. The measurement results are shown in Table 2.
[0060] Table 2 Determination results of moisture content and yield of soft tofu
[0061] Moisture content, % Output rate, % Example 1 88.88 365.23 Example 2 87.56 363.76 Example 3 87.23 364.12 Comparative Example 1 83.15 325.46 Comparative Example 2 82.23 320.48 Comparative Example 3 81.26 315.69 Comparative Example 4 80.92 318.54 Comparative Example 5 81.44 338.26 Comparative Example 6 82.22 326.89 Comparative Example 7 84.96 332.56 Comparative Example 8 83.24 333.14
[0062] The above results show that the process of not adding apple juice or not having ice water bath treatment and the process sequence of swapping the two will have a significant impact on the water content and yield of soft tofu. Only after adding apple juice and letting it stand and then taking an ice water bath can the effect of improving the water content and yield of soft tofu be achieved, indicating that the two processes play a synergistic role in improving the water content and yield of soft tofu. At the same time, by comparing the effects of Example 1 and Comparative Example 5, it can be seen that adjusting the addition amount and proportion of gypsum and gluconolactone will also lead to a decrease in the yield and water content, especially the effect on the water content is more obvious. By comparing the results of Example 1 and Comparative Examples 6 to 7, it can be seen that the addition temperature and amount of apple juice and the time of the ice water bath will also affect the water content and yield of soft tofu, and the influence of the temperature of apple juice addition is greater.
[0063] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.
Claims
1. A method for preparing soft tofu, characterized in that: The following steps are involved: When the temperature of the cooked soy milk is adjusted to 55-65°C, apple juice is added and kept warm and allowed to stand, then placed in an ice water bath and allowed to stand, then heated to 70-80°C, mixed with gypsum and gluconolactone, allowed to stand to form flocculent tofu pudding, and shaped to obtain soft tofu.
2. The preparation method according to claim 1, characterized in that: The concentration of the cooked soybean milk is 1:8-10 based on the mass ratio of dry soybeans to water.
3. The preparation method according to claim 1, characterized in that: The ratio of the apple juice to the cooked soy milk is 1.5-2.5 mL: 100 g.
4. The preparation method according to claim 1, characterized in that: The heat preservation and standing time is 8 to 12 minutes.
5. The preparation method according to claim 1, characterized in that: The standing time of the ice water bath is 30 to 40 minutes.
6. The preparation method according to claim 1, characterized in that: The mass ratio of the total amount of gypsum and gluconolactone added to the cooked soy milk is (1-2): (900-1100).
7. The preparation method according to claim 1, characterized in that: The mass ratio of the gypsum to gluconolactone is 1-3:
1.
8. The preparation method according to claim 1, characterized in that: The standing time for forming flocculent bean curd is 10 to 20 minutes.
9. The preparation method according to claim 1, characterized in that: The shaping is performed by placing the cloth in a cloth wrapping mold and letting it stand for 25 to 35 minutes.
10. Soft tofu prepared by the preparation method according to any one of claims 1 to 9.