A porous bean curd and a preparation method and application thereof
By introducing a compound of egg liquid, soy protein isolate, acetate starch and TG enzyme into tofu, and combining it with yeast fermentation, a porous structure is constructed and a gel network is formed. This solves the problems of porous tofu's easy structural breakage and poor water retention during high-temperature processing, and enables the rapid flavoring of porous tofu and the preparation of juicy soy products.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SICHUAN HUIJI FOOD
- Filing Date
- 2026-06-30
- Publication Date
- 2026-07-31
AI Technical Summary
Existing porous tofu is prone to structural breakage and poor water retention during high-temperature processing, resulting in decreased processing adaptability and sensory quality, and difficulty in absorbing flavors.
By using a method combining soy milk, egg liquid, soy protein isolate, acetate starch, and TG enzyme with yeast fermentation, a uniform porous structure is constructed and a dense gel network is formed, which is then rapidly infused with flavor through frying and braising.
Porous tofu retains its plump shape after high-temperature processing, with a well-preserved porous internal structure, good elasticity and water retention, and absorbs flavors quickly and evenly, making it into juicy soy products and snack foods.
Smart Images
Figure CN122478201A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of food processing technology, specifically relating to a porous tofu, its preparation method, and its application. Background Technology
[0002] Tofu is a traditional soybean product in my country, rich in nutrients and often referred to as "plant-based meat." Traditional tofu is mainly made through processes such as grinding soybeans into soy milk, boiling the soy milk, coagulating it, shaping it, and pressing to remove water. It has a dense structure with few internal pores. While this structure ensures tofu has a certain elasticity and texture, it also makes it difficult for flavors to penetrate during subsequent cooking; broth and sauce tend to adhere only to the surface and don't easily seep into the interior.
[0003] To address this issue, several technologies have been developed to create porous structures in tofu embryos through physical or chemical means. For example, steaming technology controls parameters such as temperature and time to cause the internal moisture of the tofu embryos to expand and escape, thus forming pores. Eggshell powder and citric acid gel technology utilizes the reaction of calcium carbonate in eggshell powder with citric acid to release carbon dioxide gas. Simultaneously, calcium ions cross-link and gel with proteins to form a porous gel structure, thereby obtaining porous tofu embryos.
[0004] However, during implementation and research, the applicant discovered the following inherent defects in the porous tofu obtained through the above technology: First, the introduction of a large number of pores disrupts the continuity and density of the tofu gel network, resulting in a decrease in the overall structural strength of the tofu embryo, making it extremely prone to breakage or rotting at high temperatures, which seriously affects its processing suitability and sensory quality; Second, when the porous tofu is subjected to high-temperature treatments such as frying, due to the poor water retention of the embryo itself, coupled with its porous structure which greatly increases the specific surface area for water evaporation, the internal water of the tofu embryo will evaporate rapidly and in large quantities during the high-temperature treatment process, resulting in the tofu being shriveled and having a rough texture.
[0005] In view of this, this invention is hereby proposed. Summary of the Invention
[0006] The purpose of this invention is to provide a porous tofu and its preparation method, wherein the porous tofu is plump, soft and tender, and has good elasticity.
[0007] The present invention also aims to provide the application of this porous tofu in soy product snack foods.
[0008] To achieve the above objectives, the first technical solution adopted by the present invention is as follows: A porous tofu comprises the following ingredients in parts by weight: 80-120 parts soy milk, 12-17 parts egg liquid, 10-15 parts soy protein isolate, 10-15 parts acetate starch, 0.6-1.0 parts yeast, and 0.2-0.6 parts TG enzyme.
[0009] Preferably, the concentration of the soy milk is 12-13.5 °Bé.
[0010] Preferably, the egg liquid is whole egg liquid or egg white liquid.
[0011] Preferably, the TG enzyme is in liquid form and has an enzyme activity >100 U / mL.
[0012] Preferably, the porous tofu is stored at 0-4 ℃.
[0013] The second technical solution adopted in this invention is: The preparation method of porous tofu as described above includes: mixing and chopping all raw materials, letting them stand at 50-55 ℃, and then cutting them into whole pieces to obtain porous tofu.
[0014] Preferably, the settling time is 20-40 minutes.
[0015] The third technical solution adopted in this invention is: The application of porous tofu in soy product snacks, as described above.
[0016] Preferably, porous tofu is deep-fried and then braised to obtain a soy product snack.
[0017] Preferably, the frying temperature is 160-180 ℃ and the frying time is 25-35 s.
[0018] The beneficial effects of this invention are as follows: This invention involves adding egg liquid, soy protein isolate, acetate starch and TG enzyme to soy milk with a concentration of 12-13.5 °Bé, combined with yeast fermentation. This not only constructs a uniform porous structure in the tofu embryo, but also forms a dense gel network. The resulting porous tofu has uniform internal pores, excellent elasticity, good water retention and a plump shape.
[0019] The porous tofu of this invention retains its full three-dimensional shape and porous internal structure after being deep-fried. Further braising allows it to quickly absorb the braising liquid, and the water-retaining capacity of the gel network locks the broth inside the product, thereby achieving a rapid, uniform, and deep flavoring effect, resulting in a juicy and delicious soy product snack. Attached Figure Description
[0020] Figure 1 A longitudinal cross-sectional comparison of porous tofu in the examples and comparative examples; Figure 2The images show the actual appearance and longitudinal section of porous tofu and traditional gypsum tofu after frying, as shown in Example 1. A and B are images of porous tofu, and C and D are images of traditional gypsum tofu. Figure 3 The image shows a longitudinal cross-section of porous tofu and traditional gypsum tofu from Example 1 after frying and braising. Detailed Implementation
[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the following detailed description of the invention is provided in conjunction with embodiments. Those skilled in the art will understand that the following embodiments are merely exemplary and not intended to limit the scope of the invention. Furthermore, in the following description, unless specific conditions are specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.
[0022] The first embodiment of the present invention provides a porous tofu, comprising the following ingredients in parts by weight: 80-120 parts soy milk, 12-17 parts egg liquid, 10-15 parts soy protein isolate, 10-15 parts acetate starch, 0.6-1.0 parts yeast, and 0.2-0.6 parts TG enzyme.
[0023] This embodiment introduces a compound raw material combination of egg liquid, soy protein isolate, starch acetate and TG enzyme to assist yeast in gas production, thereby forming suitable pores in the tofu. At the same time, it promotes protein cross-linking, builds a strong gel network structure, stabilizes the internal structure of the tofu, prevents the tofu from collapsing, and can more effectively bind water, thus obtaining a plump, elastic and water-retaining porous tofu.
[0024] In a specific embodiment, the soy milk is prepared using conventional soy milk production processes in the art, preferably using a cooked soy milk process. As an example, the preparation method includes: soaking soybeans in water until there is no hard core, then adding water at a mass ratio of dry soybeans to water of 1:4-4.5 and grinding the soybeans into a paste, then adjusting the paste with water to a soy milk concentration of 12-13.5°Bé, cooking the soy milk with residue to above 90°C, filtering to remove the soy residue, and obtaining the desired soy milk.
[0025] In specific implementations, raw materials such as egg liquid can be conventionally selected and adjusted according to product requirements and process conditions. As an example: egg liquid is preferably whole egg liquid or egg white liquid, more preferably egg white liquid; acetate starch is preferably cassava acetate starch with a low gelatinization temperature; yeast is preferably low-sugar, high-activity bread yeast; TG enzyme is preferably liquid TG enzyme with an enzyme activity >100 U / mL.
[0026] It should be noted that the porous tofu of this embodiment is not suitable for high-temperature enzyme inactivation or sterilization, as this will cause product deformation, cooling shrinkage, and loss of pores. Therefore, the product should be stored directly at 0-4 ℃. At this temperature, the activity of TG enzyme is significantly inhibited and cannot continue to function, ensuring stable product quality.
[0027] The second embodiment of the present invention provides a method for preparing porous tofu as described above, comprising: mixing all raw materials, chopping and stirring, allowing them to ferment, and then cutting them into whole pieces to obtain porous tofu.
[0028] In this embodiment, the raw materials are mixed and chopped for 10-20 seconds to form a uniform paste. The resulting paste is placed in a molding pan and allowed to stand at 50-55°C for 20-40 minutes. It should be noted that the optimal fermentation temperature for yeast is usually 28-38°C, but if the paste obtained in this embodiment is fermented at 38°C, the fermentation is slow and the effect is not ideal, resulting in unstable product quality. The applicant has found in long-term research that when the resulting paste is sized to 10 cm × 20 cm × (4-5) cm and placed at 50-55°C for standing treatment, the paste slowly heats up before and during the treatment, the yeast metabolism is vigorous, and sufficient CO2 gas is continuously produced, which promotes the formation of uniform and fine pores inside the paste. In the later stage, when the material temperature rises to 40°C and above, the yeast gradually becomes inactive, while the TG enzyme activity is significantly increased, catalyzing the cross-linking between protein molecules, thereby strengthening the gel network structure and giving the product good elasticity and water retention. After processing, you will obtain porous tofu with uniform pores, excellent elasticity, good water retention, and a plump shape.
[0029] The third embodiment of the present invention provides the application of porous tofu as described above in soy product snacks.
[0030] In this embodiment, porous tofu is deep-fried and then braised to obtain a soy-based snack food. It should be noted that the porous tofu provided in this embodiment has internal pores encased in a protein membrane. If steamed or boiled, the protein membrane softens upon heating or water absorption, causing the product to deform, shrink upon cooling, and the pores to disappear. Through long-term research, the applicant has found that deep-frying this porous tofu at 160-180°C for 25-35 seconds maintains its plump shape and internal porous structure. Further braising allows it to quickly absorb the braising liquid, and the gel network's water-retention capacity locks the liquid inside the product, achieving a rapid, uniform, and deep flavor infusion. In practical applications, braising for about 10 minutes after deep-frying yields a plump and juicy soy-based snack food.
[0031] The following will disclose specific embodiments for implementing this application, along with corresponding comparative examples to demonstrate the relevant technical effects of this application.
[0032] All raw materials used in the following examples were purchased from the market. Among them, the yeast was Angel low-sugar high-activity bread yeast, the TG enzyme was liquid TG enzyme with an enzyme activity >100 U / mL, and the acetate starch was tapioca acetate starch.
[0033] Example 1: Preparation of porous tofu Raw materials, by weight, include: 100 parts of 13 °Bé soy milk, 15 parts of whole egg liquid, 12 parts of soy protein isolate, 12 parts of acetate starch, 0.8 parts of yeast, and 0.4 parts of TG enzyme.
[0034] Mix and chop the above ingredients for 20 seconds, then pour them into a forming pan and let them stand at 52°C for 30 minutes. After that, cut them into pieces to make porous tofu.
[0035] Example 2: Preparation of porous tofu Raw materials, by weight, include: The mixture consisted of 90 parts of 12 °Bé soy milk, 13 parts of whole egg liquid, 10 parts of soy protein isolate, 10 parts of acetate starch, 0.6 parts of yeast, and 0.3 parts of TG enzyme.
[0036] Mix and chop the above ingredients for 10 seconds, then pour them into a forming pan and let them stand at 50°C for 35 minutes. After that, cut them into pieces to make porous tofu.
[0037] Example 3: Preparation of porous tofu Raw materials, by weight, include: 110 parts of soy milk with a concentration of 13.5 °Bé, 16 parts of whole egg liquid, 14 parts of soy protein isolate, 14 parts of starch acetate, 0.9 parts of yeast, and 0.5 parts of TG enzyme.
[0038] Mix and chop the above ingredients for 15 seconds, then pour them into a forming pan and let them stand at 55°C for 25 minutes. After that, cut them into pieces to make porous tofu.
[0039] Comparative Example 1 The preparation method is the same as in Example 1, except that no starch is added.
[0040] Comparative Example 2 The preparation method is the same as in Example 1, except that no soy protein isolate is added.
[0041] Comparative Example 3 The preparation method is the same as in Example 1, except that no egg liquid is added.
[0042] Comparative Example 4 The preparation method is the same as in Example 1, except that the concentration of the soy milk is 11 °Bé.
[0043] Comparative Example 5 The preparation method is the same as in Example 1, except that the concentration of the soy milk is 14 °Bé.
[0044] Experimental Example 1 The porous tofu prepared in Examples 1-3 and Comparative Examples 1-5 was longitudinally cut, and the distribution of pores in the cross-section, as well as its overall appearance and texture, were observed. The results are as follows: Figure 1 As shown.
[0045] Depend on Figure 1 As can be seen, the porous tofu prepared in Examples 1-3 has a large number of fine pores distributed on its cross-section, exhibiting a typical porous network structure with uniform pore size and distribution. Compared with the examples, Comparative Example 1 did not add starch, and the product also exhibited a uniform porous structure, with only a slight decrease in the number of pores; Comparative Example 2 did not add soy protein isolate, and the product had very few pores; Comparative Example 3 omitted the addition of egg liquid, and Comparative Examples 4-5 changed the concentration of soy milk, resulting in a significant decrease in the number of pores in the product, and their distribution was uneven.
[0046] Experiment Example 2 The sensory evaluation of each group of tofu samples was further conducted using a 9-point scale. The scoring criteria were: 1 point - very poor, 2 points - very poor, 3 points - poor, 4 points - slightly poor, 5 points - average, 6 points - slightly good, 7 points - good, 8 points - very good, and 9 points - excellent.
[0047] Prior to the sensory evaluation, 15 sensory evaluators were trained. A cube was used as the reference for "fullness," toast bread as the reference for "pore uniformity," dried tofu and dried egg as the reference for "elasticity," and steamed egg custard as the reference for "tenderness." Fullness and pore uniformity were judged visually, while elasticity and tenderness were judged by touch. After passing the training, the evaluators independently scored the four indicators (fullness, pore uniformity, elasticity, and tenderness) for each group of samples. The results are shown in Table 1.
[0048] Table 1. Sensory evaluation results of porous tofu in each group .
[0049] According to the sensory evaluation results in Table 1, the porous tofu prepared in Examples 1-3 is plump, has good elasticity, and is appropriately tender. In contrast, Comparative Example 1, due to the lack of added starch, has an insufficiently firm overall shape, is too soft and fragile, and is unsuitable for product processing and sales; Comparative Example 2, without added soy protein isolate, although its overall shape appears normal, has a soft texture, lacks elasticity, and is fragile, also unsuitable for product processing and sales; Comparative Example 3, without added egg liquid, has an insufficiently soft texture, and its overall index scores are lower than those of the examples; Comparative Example 4 has too low a soy milk concentration, making it difficult to shape the tofu, which collapses immediately upon leaving the 50-55 ℃ environment and is difficult to cut into a normal shape; Comparative Example 5 has too high a soy milk concentration, resulting in severe scorching and false boiling during the soy milk cooking process, a very low yield of cooked soy milk, and the soy milk becomes semi-solid after cooling, ultimately producing a coarse-textured product.
[0050] Experimental Example 3 The porous tofu prepared in Example 1 was cut into pieces measuring 6.0 cm × 2.5 cm × 1.0 cm, and deep-fried in oil at 180 ℃ for 35 s. After draining the oil, the pieces were cooled to 60 ℃ and their overall appearance was observed (see [link]). Figure 2 A); then, while still hot, make a longitudinal cut to observe the distribution of perforations in the cut (see...). Figure 2 B). Traditional gypsum tofu was used as a control group; its overall appearance and longitudinal section are shown in [image missing]. Figure 2 C, 2D.
[0051] Depend on Figure 2 As can be seen, the porous tofu prepared in Example 1 of this invention, after being deep-fried, retains its plump shape and porous internal structure, exhibiting a meaty texture. In contrast, traditional gypsum tofu, after being deep-fried, shows slight surface shrinkage but a firm internal structure.
[0052] The fried and cooled tofu was placed in a simmering (90°C) brine and cooked for 10 minutes. It was then removed, drained, and cooled to 60°C before being sliced lengthwise while still hot. The cross-sectional appearance of the two products was observed (see...). Figure 3 ).
[0053] according to Figure 3 It can be seen that after further braising, the porous tofu in Example 1 still maintains a relatively full texture, and the internal pores are fully filled with braising liquid, showing a juicy state; while traditional gypsum tofu only has a few pores inside, with no obvious substantial changes, and its ability to absorb broth is extremely poor.
[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A porous tofu, characterized by, The ingredients include the following parts by weight: 80-120 parts soy milk, 12-17 parts egg liquid, 10-15 parts soy protein isolate, 10-15 parts starch acetate, 0.6-1.0 parts yeast, and 0.2-0.6 parts TG enzyme.
2. The porous tofu according to claim 1, wherein The concentration of the soy milk is 12-13.5 °Bé.
3. The porous tofu as described in claim 1, characterized in that, The egg liquid is either whole egg liquid or egg white liquid.
4. The porous tofu as described in claim 1, characterized in that, The TG enzyme is in liquid form and has an enzyme activity >100 U / mL.
5. The porous tofu as described in claim 1, characterized in that, The porous tofu is stored at 0-4 ℃.
6. The method for preparing porous tofu according to any one of claims 1-5, characterized in that, include: After mixing and chopping all the ingredients, let them stand at 50-55 ℃, and then cut them into whole pieces to make porous tofu.
7. The preparation method according to claim 6, characterized in that, The settling time is 20-40 minutes.
8. The application of porous tofu as described in any one of claims 1-5 in soy product snacks.
9. The application as described in claim 8, characterized in that, Porous tofu is deep-fried and then braised to obtain a soy product snack.
10. The application as described in claim 8, characterized in that, The frying temperature is 160-180 ℃, and the frying time is 25-35 s.