Preparation method and application of fried bean curd

Abstract

The invention relates to the technical field of food processing, in particular to a preparation method and application of fried bean curd. Soybeans are soaked with water to obtain soaked soybeans, the soaked soybeans are ground into thick liquid, raw soybean milk is obtained and then mixed with sweet potato starch, mixed thick liquid is obtained, the thick liquid is boiled, curdled and left to stand, beancurd jelly is obtained and then pressed and diced, bean curd blocks are obtained and sequentially subjected to first-time deep-frying and second-time deep-frying, and the fried bean curd is obtained. The sweet potato starch and vacuum frying are combined, the temperature of two times of frying is reduced, the frying time is shortened, and the obtained fried bean curd is in a honeycomb shape, does not collapse after being cooled, and is golden yellow in appearance and complete in shape.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, and in particular to a preparation method and application of fried tofu. Background Art

[0002] Soybeans are rich in protein, fat, carbohydrates, crude fiber, various minerals and vitamins, and are often used to make various soy products. The raw material of fried tofu is soybeans, which are made through multiple processes such as grinding, pressing, and frying. The skin is smooth, soft, firm, elastic, and golden in color. It can be used as a main dish for steaming, frying, and stewing, and can also be used as an ingredient for a variety of meat dishes. It is a good product for both meat and vegetarian banquets. In addition, fried tofu contains high-quality protein, various amino acids, unsaturated fatty acids, lecithin, etc., and the content of iron and calcium is also high. It is deeply loved by consumers and is one of the traditional dishes of the Chinese people.

[0003] In the prior art, fried tofu is prepared by traditional grinding, residue filtering, slurry boiling, slurry forming and pressing, and then cut into pieces and fried. The resulting fried tofu is often not fluffy and is prone to collapse after frying. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a preparation method and application of fried tofu. The fried tofu prepared by the method provided by the present invention is loose and porous and not easy to collapse.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The invention provides a method for preparing fried tofu, comprising the following steps:

[0007] 1) soaking soybeans in water to obtain soaked soybeans;

[0008] 2) grinding the soaked soybeans obtained in step 1) to obtain raw soybean milk;

[0009] 3) mixing the raw soybean milk obtained in step 2) with sweet potato starch to obtain a mixed slurry;

[0010] 4) boiling the mixed slurry obtained in step 3) to obtain cooked soy milk;

[0011] 5) Adding a coagulant to the cooked soy milk obtained in step 4) and letting it stand to obtain soymilk;

[0012] 6) pressing and cutting the tofu obtained in step 5) to obtain tofu blocks;

[0013] 7) deep-frying the tofu blocks obtained in step 6) for the first time and for the second time in sequence to obtain fried tofu;

[0014] The first frying is vacuum frying at a temperature of 110-115° C. for 2-4 minutes;

[0015] The second frying is conventional frying at a temperature of 130-140° C. for 5-7 minutes.

[0016] Preferably, the soaking conditions in step 1) include: the mass ratio of the soybeans to water is 10:1, and the soaking time is 10 to 15 hours.

[0017] Preferably, the conditions for refining in step 2) include: the mass ratio of the soaked soybeans to water is 1:3-5.

[0018] Preferably, the mass ratio of raw soy milk to sweet potato starch in step 3) is 100:10-15.

[0019] Preferably, the conditions for boiling the slurry in step 4) include: boiling for 8 to 10 minutes.

[0020] Preferably, the coagulant in step 5) comprises magnesium chloride and / or calcium sulfate, and the mass ratio of the coagulant to cooked soy milk is 2.5-3.5:100.

[0021] Preferably, the conditions for the slurrying in step 5) include: a temperature of 70 to 80° C., standing the slurry for 15 to 20 minutes after the slurrying is completed, and removing the yellow slurry water.

[0022] Preferably, the length, width and height of the tofu block in step 6) are 4-5 cm×4-5 cm×1-2 cm respectively.

[0023] Preferably, the first frying in step 7) is vacuum frying at a temperature of 110° C. for 3 minutes;

[0024] The second frying is conventional frying at a temperature of 130° C. for 6 minutes.

[0025] The present invention also provides application of the preparation method described in the above technical solution in improving the looseness and porosity of fried tofu.

[0026] Beneficial effects:

[0027] The invention combines sweet potato starch with vacuum frying, which not only reduces the temperature of two fryings and shortens the frying time, but also makes the obtained fried tofu honeycomb-shaped inside, without collapse after cooling, golden yellow outside and complete in shape. DETAILED DESCRIPTION

[0028] The invention provides a method for preparing fried tofu, comprising the following steps:

[0029] 1) soaking soybeans in water to obtain soaked soybeans;

[0030] 2) grinding the soaked soybeans obtained in step 1) to obtain raw soybean milk;

[0031] 3) mixing the raw soybean milk obtained in step 2) with sweet potato starch to obtain a mixed slurry;

[0032] 4) boiling the mixed slurry obtained in step 3) to obtain cooked soy milk;

[0033] 5) Adding a coagulant to the cooked soy milk obtained in step 4) and letting it stand to obtain soymilk;

[0034] 6) pressing and cutting the tofu obtained in step 5) to obtain tofu blocks;

[0035] 7) deep-frying the tofu blocks obtained in step 6) for the first time and for the second time in sequence to obtain fried tofu;

[0036] The first frying is vacuum frying at a temperature of 110-115° C. for 2-4 minutes;

[0037] The second frying is conventional frying at a temperature of 130-140° C. for 5-7 minutes.

[0038] The present invention soaks soybeans in water to obtain soaked soybeans. The present invention has no special limitation on the source of soybeans. The present invention preferably removes impurities and moldy soybeans from the soybeans before soaking them in water. In the present invention, the soaking conditions include: the mass ratio of the soybeans to water is preferably 10:1, and the soaking time is preferably 10 to 15 hours. The present invention preferably cleans the soaked soybeans before grinding.

[0039] The present invention grinds the soaked soybeans to obtain raw soybean milk. In the present invention, the grinding conditions preferably include: the mass ratio of the soaked soybeans to water is 1:3-5. The present invention preferably filters the slurry after grinding, and the filtrate is raw soybean milk. The present invention has no special limitation on the filtration. Those skilled in the art can use conventional filtering methods to prepare raw soybean milk after grinding, which is not limited here.

[0040] The present invention mixes the obtained raw soy milk with sweet potato starch to obtain a mixed slurry. In the present invention, the mass ratio of the raw soy milk to the sweet potato starch is preferably 100:10-15. The present invention has no special limitation on the source of the sweet potato starch, and it can be homemade or commercially available using conventional methods.

[0041] The present invention boils the obtained mixed slurry to obtain cooked soy milk. In the present invention, the boiling conditions preferably include: boiling for 8 to 10 minutes.

[0042] The present invention uses a coagulant to slurry the obtained cooked soy milk and allows it to stand to obtain tofu brain. In the present invention, the coagulant preferably includes magnesium chloride and / or calcium sulfate, and the mass ratio of the coagulant to the cooked soy milk is preferably 2.5-3.5:100. In the present invention, the slurrying conditions preferably include: a temperature of 70-80°C, standing for 15-20 minutes after the slurrying is completed, and removing the yellow slurry water.

[0043] The present invention presses and cuts the obtained bean curd into blocks to obtain tofu blocks. In the present invention, the length, width and height of the tofu blocks are preferably 4-5 cm×4-5 cm×1-2 cm, respectively. The present invention does not specifically limit the pressing conditions, and those skilled in the art can follow conventional operations, which will not be described in detail here.

[0044] The present invention sequentially performs the first frying and the second frying on the obtained tofu blocks to obtain fried tofu; the first frying is vacuum frying, the temperature is 110-115°C, and the time is 2-4 minutes; the second frying is conventional frying, the temperature is 130-140°C, and the time is 5-7 minutes. In the present invention, the first frying is vacuum frying, the temperature is preferably 110°C, and the time is preferably 3 minutes; the second frying is conventional frying, the temperature is preferably 130°C, and the time is preferably 6 minutes. The present invention has no special restrictions on other conditions of the vacuum frying, as long as the frying temperature can be reached. The present invention has no special restrictions on the oil used for frying, and conventional edible oil can be used for frying, such as soybean oil, peanut oil, etc.

[0045] The present invention also provides application of the preparation method described in the above technical solution in improving the looseness and porosity of fried tofu.

[0046] In order to further illustrate the present invention, the present invention is described in detail below in conjunction with embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0047] Example 1

[0048] A method for preparing fried tofu, comprising the following steps:

[0049] 1) removing impurities and mildew from soybeans, and soaking them in water to obtain soaked soybeans, wherein the mass ratio of soybeans to water is 10:1, and the soaking time is 10 hours;

[0050] 2) mixing the soaked soybeans obtained in step 1) with water in a mass ratio of 1:3, grinding and filtering, and the filtrate is raw soybean milk;

[0051] 3) mixing the raw soybean milk obtained in step 2) with sweet potato starch to obtain a mixed slurry, wherein the mass ratio of the raw soybean milk to the sweet potato starch is 10:1;

[0052] 4) boiling the mixed slurry obtained in step 3) for 8 minutes to obtain cooked soy milk;

[0053] 5) the cooked soy milk obtained in step 4) is slurried with magnesium chloride at 80° C., with a mass ratio of magnesium chloride to cooked soy milk being 3.5:100. After the slurrying is completed, the mixture is allowed to stand for 20 minutes, and the yellow soy milk water is removed to obtain soymilk;

[0054] 6) Pressing and cutting the tofu obtained in step 5) to obtain tofu blocks, wherein the length, width and height of the tofu blocks are 5 cm×5 cm×1.5 cm respectively;

[0055] 7) deep-frying the tofu blocks obtained in step 6) for the first time and the second time in sequence to obtain fried tofu;

[0056] The first frying was vacuum frying at 110°C for 3 min.

[0057] The second frying was conventional frying at a temperature of 130°C for 6 minutes.

[0058] The prepared fried tofu has a golden appearance, an oily and bean aroma, no peculiar smell, a complete and uniform shape, a crust on the surface, a honeycomb shape (loose and porous) inside, does not collapse after cooling, has no foreign impurities visible to the naked eye, a moisture content of 40.2g / 100g, and a protein content of 23.6g / 100g.

[0059] Example 2

[0060] A method for preparing fried tofu, comprising the following steps:

[0061] 1) removing impurities and mildew from soybeans, and soaking them in water to obtain soaked soybeans, wherein the mass ratio of soybeans to water is 10:1, and the soaking time is 12 hours;

[0062] 2) mixing the soaked soybeans obtained in step 1) with water in a mass ratio of 1:4, grinding and filtering, and the filtrate is raw soybean milk;

[0063] 3) mixing the raw soybean milk obtained in step 2) with sweet potato starch to obtain a mixed slurry, wherein the mass ratio of the raw soybean milk to the sweet potato starch is 100:15;

[0064] 4) boiling the mixed slurry obtained in step 3) for 10 minutes to obtain cooked soy milk;

[0065] 5) the cooked soy milk obtained in step 4) is slurried with magnesium chloride at 75° C., with the mass ratio of magnesium chloride to cooked soy milk being 2.5:100. After the slurrying is completed, the mixture is allowed to stand for 20 minutes, and the yellow soy milk water is removed to obtain soymilk;

[0066] 6) Pressing and cutting the tofu obtained in step 5) to obtain tofu blocks, wherein the length, width and height of the tofu blocks are 4 cm×4 cm×1.5 cm respectively;

[0067] 7) deep-frying the tofu blocks obtained in step 6) for the first time and the second time in sequence to obtain fried tofu;

[0068] The first frying was vacuum frying at 115°C for 2 min.

[0069] The second frying was conventional frying at 140°C for 5 min.

[0070] The prepared fried tofu has a golden appearance, an oily and bean aroma, no peculiar smell, a complete and uniform shape, a crust on the surface, a honeycomb shape (loose and porous) inside, does not collapse after cooling, has no foreign impurities visible to the naked eye, a moisture content of 41.4g / 100g, and a protein content of 22.9g / 100g.

[0071] Example 3

[0072] A method for preparing fried tofu, comprising the following steps:

[0073] 1) removing impurities and mildew from soybeans, and soaking them in water to obtain soaked soybeans, wherein the mass ratio of soybeans to water is 10:1, and the soaking time is 12 hours;

[0074] 2) mixing the soaked soybeans obtained in step 1) with water in a mass ratio of 1:4, grinding and filtering, and the filtrate is raw soybean milk;

[0075] 3) mixing the raw soybean milk obtained in step 2) with sweet potato starch to obtain a mixed slurry, wherein the mass ratio of the raw soybean milk to the sweet potato starch is 10:1;

[0076] 4) boiling the mixed slurry obtained in step 3) for 8 minutes to obtain cooked soy milk;

[0077] 5) the cooked soy milk obtained in step 4) is slurried with magnesium chloride at 70° C., with a mass ratio of magnesium chloride to cooked soy milk being 3:100. After the slurrying is completed, the mixture is allowed to stand for 15 minutes, and the yellow soy milk water is removed to obtain soymilk;

[0078] 6) Pressing and cutting the tofu obtained in step 5) to obtain tofu blocks, wherein the length, width and height of the tofu blocks are 4 cm×4 cm×2 cm respectively;

[0079] 7) deep-frying the tofu blocks obtained in step 6) for the first time and the second time in sequence to obtain fried tofu;

[0080] The first frying was vacuum frying at 110°C for 4 min.

[0081] The second frying was conventional frying at a temperature of 135°C for 5 min.

[0082] The prepared fried tofu has a golden appearance, an oily and bean aroma, no peculiar smell, a complete and uniform shape, a crust on the surface, a honeycomb shape (loose and porous) inside, does not collapse after cooling, has no foreign impurities visible to the naked eye, a moisture content of 41.8g / 100g, and a protein content of 22.1g / 100g.

[0083] Example 4

[0084] A method for preparing fried tofu, comprising the following steps:

[0085] 1) removing impurities and mildew from soybeans, and soaking them in water to obtain soaked soybeans, wherein the mass ratio of soybeans to water is 10:1, and the soaking time is 15 hours;

[0086] 2) mixing the soaked soybeans obtained in step 1) with water in a mass ratio of 1:4, grinding and filtering, and the filtrate is raw soybean milk;

[0087] 3) mixing the raw soybean milk obtained in step 2) with sweet potato starch to obtain a mixed slurry, wherein the mass ratio of the raw soybean milk to the sweet potato starch is 100:12;

[0088] 4) boiling the mixed slurry obtained in step 3) for 9 minutes to obtain cooked soy milk;

[0089] 5) The cooked soy milk obtained in step 4) is slurried with magnesium chloride at 75° C., with a mass ratio of magnesium chloride to cooked soy milk being 2.5:100. After the slurrying is completed, the mixture is allowed to stand for 15 minutes, and the yellow soy milk water is removed to obtain soymilk;

[0090] 6) Pressing and cutting the tofu obtained in step 5) to obtain tofu blocks, wherein the length, width and height of the tofu blocks are 5 cm×5 cm×1 cm respectively;

[0091] 7) deep-frying the tofu blocks obtained in step 6) for the first time and the second time in sequence to obtain fried tofu;

[0092] The first frying was vacuum frying at 115°C for 4 min.

[0093] The second frying was conventional frying at a temperature of 135°C for 6 minutes.

[0094] The prepared fried tofu has a golden appearance, an oily and bean aroma, no peculiar smell, a complete and uniform shape, a crust on the surface, a honeycomb shape (loose and porous) inside, does not collapse after cooling, has no foreign impurities visible to the naked eye, a moisture content of 42.7g / 100g, and a protein content of 24.1g / 100g.

[0095] Comparative Example 1

[0096] A method for preparing fried tofu, comprising the following steps:

[0097] 1) removing impurities and mildew from soybeans, and soaking them in water to obtain soaked soybeans, wherein the mass ratio of soybeans to water is 10:1, and the soaking time is 10 hours;

[0098] 2) mixing the soaked soybeans obtained in step 1) with water in a mass ratio of 1:3, grinding and filtering, and the filtrate is raw soybean milk;

[0099] 3) mixing the raw soybean milk obtained in step 2) with pea starch to obtain a mixed slurry, wherein the mass ratio of the raw soybean milk to the sweet potato starch is 10:1;

[0100] 4) boiling the mixed slurry obtained in step 3) for 8 minutes to obtain cooked soy milk;

[0101] 5) the cooked soy milk obtained in step 4) is slurried with magnesium chloride at 80° C., with a mass ratio of magnesium chloride to cooked soy milk being 3.5:100. After the slurrying is completed, the mixture is allowed to stand for 20 minutes, and the yellow soy milk water is removed to obtain soymilk;

[0102] 6) Pressing and cutting the tofu obtained in step 5) to obtain tofu blocks, wherein the length, width and height of the tofu blocks are 5 cm×5 cm×1.5 cm respectively;

[0103] 7) deep-frying the tofu blocks obtained in step 6) for the first time and the second time in sequence to obtain fried tofu;

[0104] The first frying was vacuum frying at 110°C for 3 min.

[0105] The second frying was conventional frying at a temperature of 130°C for 6 minutes.

[0106] The prepared fried tofu has a golden appearance, an oily and bean aroma, no peculiar smell, a complete and uniform shape, a crust on the surface, and basically no honeycomb (loose and porous) inside. It collapses after cooling, has no foreign impurities visible to the naked eye, has a moisture content of 40.4g / 100g, and a protein content of 23.9g / 100g.

[0107] Comparative Example 2

[0108] A method for preparing fried tofu, comprising the following steps:

[0109] 1) removing impurities and mildew from soybeans, and soaking them in water to obtain soaked soybeans, wherein the mass ratio of soybeans to water is 10:1, and the soaking time is 10 hours;

[0110] 2) mixing the soaked soybeans obtained in step 1) with water in a mass ratio of 1:3, grinding and filtering, and the filtrate is raw soybean milk;

[0111] 3) boiling the raw soybean milk obtained in step 3) for 8 minutes to obtain cooked soybean milk;

[0112] 4) the cooked soy milk obtained in step 4) is slurried with magnesium chloride at 80° C., with a mass ratio of magnesium chloride to cooked soy milk being 3.5:100. After the slurrying is completed, the mixture is allowed to stand for 20 minutes, and the yellow soy milk water is removed to obtain soymilk;

[0113] 5) pressing and cutting the tofu obtained in step 5) to obtain tofu blocks, wherein the length, width and height of the tofu blocks are 5 cm×5 cm×1.5 cm respectively;

[0114] 6) deep-frying the tofu blocks obtained in step 6) for the first time and for the second time in sequence to obtain fried tofu;

[0115] The first frying was vacuum frying at 110°C for 3 min.

[0116] The second frying was conventional frying at a temperature of 130°C for 6 minutes.

[0117] The prepared fried tofu has a golden appearance, an oily and bean aroma, no peculiar smell, a complete and uniform shape, a crust on the surface, and basically no honeycomb (loose and porous) inside. It collapses after cooling, and has no foreign impurities visible to the naked eye. The moisture content is 41.1g / 100g and the protein content is 22.8g / 100g.

[0118] Comparative Example 3

[0119] A method for preparing fried tofu, comprising the following steps:

[0120] 1) removing impurities and mildew from soybeans, and soaking them in water to obtain soaked soybeans, wherein the mass ratio of soybeans to water is 10:1, and the soaking time is 10 hours;

[0121] 2) mixing the soaked soybeans obtained in step 1) with water in a mass ratio of 1:3, grinding and filtering, and the filtrate is raw soybean milk;

[0122] 3) mixing the raw soybean milk obtained in step 2) with sweet potato starch to obtain a mixed slurry, wherein the mass ratio of the raw soybean milk to the sweet potato starch is 10:1;

[0123] 4) boiling the mixed slurry obtained in step 3) for 8 minutes to obtain cooked soy milk;

[0124] 5) the cooked soy milk obtained in step 4) is slurried with magnesium chloride at 80° C., with a mass ratio of magnesium chloride to cooked soy milk being 3.5:100. After the slurrying is completed, the mixture is allowed to stand for 20 minutes, and the yellow soy milk water is removed to obtain soymilk;

[0125] 6) Pressing and cutting the tofu obtained in step 5) to obtain tofu blocks, wherein the length, width and height of the tofu blocks are 5 cm×5 cm×1.5 cm respectively;

[0126] 7) deep-frying the tofu blocks obtained in step 6) for the first time and the second time in sequence to obtain fried tofu;

[0127] The first frying is conventional frying at a temperature of 130° C. for 9 minutes;

[0128] The second frying is conventional frying at a temperature of 160° C. for 10 minutes.

[0129] The prepared fried tofu has a golden appearance, an oily and bean aroma, no peculiar smell, a complete and uniform shape, a crust on the surface, and basically no honeycomb (loose and porous) inside. It collapses after cooling, and has no foreign impurities visible to the naked eye. The moisture content is 41.5g / 100g and the protein content is 23.1g / 100g.

[0130] It can be concluded from the above embodiments and comparative examples that the present invention combines sweet potato starch with vacuum frying, which not only reduces the temperature of the two frying and shortens the frying time, but also obtains fried tofu with a honeycomb shape inside, no collapse after cooling, a golden appearance, and a complete shape.

[0131] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing fried tofu, characterized in that: The following steps are involved: 1) soaking soybeans in water to obtain soaked soybeans; 2) grinding the soaked soybeans obtained in step 1) to obtain raw soybean milk; 3) mixing the raw soybean milk obtained in step 2) with sweet potato starch to obtain a mixed slurry; 4) boiling the mixed slurry obtained in step 3) to obtain cooked soy milk; 5) Adding a coagulant to the cooked soy milk obtained in step 4) and letting it stand to obtain soymilk; 6) pressing and cutting the tofu obtained in step 5) to obtain tofu blocks; 7) deep-frying the tofu blocks obtained in step 6) for the first time and for the second time in sequence to obtain fried tofu; The first frying is vacuum frying at a temperature of 110-115° C. for 2-4 minutes; The second frying is conventional frying at a temperature of 130-140° C. for 5-7 minutes.

2. The preparation method according to claim 1, characterized in that: The soaking conditions in step 1) include: the mass ratio of the soybeans to water is 10:1, and the soaking time is 10 to 15 hours.

3. The preparation method according to claim 1, characterized in that: The conditions for refining in step 2) include: the mass ratio of the soaked soybeans to water is 1:3-5.

4. The preparation method according to claim 1, characterized in that: In the step 3), the mass ratio of raw soy milk to sweet potato starch is 100:10-15.

5. The preparation method according to claim 1, characterized in that: The conditions for boiling the slurry in step 4) include: boiling for 8 to 10 minutes.

6. The preparation method according to claim 1, characterized in that: In step 5), the coagulant includes magnesium chloride and / or calcium sulfate, and the mass ratio of the coagulant to cooked soy milk is 2.5-3.5:

100.

7. The preparation method according to claim 1, characterized in that: The conditions for the step 5) of slurrying include: a temperature of 70 to 80° C., and after the slurrying is completed, the slurry is allowed to stand for 15 to 20 minutes to remove the yellow slurry water.

8. The preparation method according to claim 1, characterized in that: The length, width and height of the tofu block in step 6) are 4-5 cm×4-5 cm×1-2 cm respectively.

9. The preparation method according to claim 1, characterized in that: The first frying in step 7) is vacuum frying at a temperature of 110° C. for 3 minutes; The second frying is conventional frying at a temperature of 130° C. for 6 minutes.

10. Use of the preparation method according to claims 1 to 9 in improving the looseness and porosity of fried tofu.