Blood tofu and preparation method thereof

Abstract

A type of blood tofu, characterized by being made primarily from tofu, duck blood, pork belly, and soybean residue, and supplemented with vegetable oil, Sichuan peppercorn powder, chili powder, salt, eggs, chicken essence, yeast powder, hydroxypropyl cellulose, and carrageenan. The blood tofu prepared by this invention effectively retains its internal moisture, maintains a stable structure without cracking, and holds its shape well when cut after long-term storage. It has a delicate and soft texture, free of powdery or gritty feel, and has a shelf life of up to 12 months without spoilage, maintaining a fresh taste and elastic texture.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, and in particular to blood bean curd and a preparation method thereof. Background Art

[0002] Blood tofu is also called "blood balls". It is different from blood curd formed by coagulation of animal blood. It is mainly made of tofu, with appropriate amount of pig blood and pork. In recent years, eggs have been added to the raw materials. Every household will prepare it in November and December every year to meet the needs of several months. The protein content of tofu products is higher than that of soybeans, and tofu protein is a complete protein. Tofu not only contains eight essential amino acids for the human body, but also contains carbohydrates, vitamins and minerals. Duck blood is called the "scavenger" of the human body. Compared with pig blood, duck blood has a richer iron content. Pig blood has a slight bloody smell. After high-temperature treatment, duck blood has no bloody smell and a duck fragrance. Duck blood has a smooth texture, small pores, and a more delicate and smooth taste than pig blood. Therefore, duck blood is used instead of pig blood to make blood tofu, which has higher nutritional value and better taste. However, the use of duck blood and tofu to prepare blood tofu also faces the following problems: (1) It has low viscosity and is not easy to shape after drying. It is easy to harden or even crack. (2) The delicate duck blood and the rough duck blood form a contrast, highlighting the powdery and gritty texture of the blood tofu. (3) The shelf life is short, which can easily cause the microbial limit to exceed the standard and cause deterioration. Summary of the invention

[0003] Based on the above problems, the present invention provides a kind of blood tofu.

[0004] Another object of the present invention is to provide a method for preparing blood tofu, wherein the prepared blood tofu has reduced powdery and gritty texture, and effectively inhibits the blood tofu from becoming dry and hard, prevents cracking, and prolongs its shelf life.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] A blood tofu is characterized by being composed of tofu, duck blood, pork belly and bean dregs as main raw materials, and vegetable oil, pepper powder, chili powder, salt, eggs, chicken essence, yeast powder, hydroxypropyl cellulose and carrageenan as auxiliary materials.

[0007] Furthermore, the amount of each material used is 40-42 parts by mass of tofu, 5-7 parts of duck blood, 7-9 parts of pork belly, 5-6 parts of bean dregs, 5-5.5 parts of vegetable oil, 0.5-0.8 parts of pepper powder, 1-2 parts of chili powder, 5-5.5 parts of salt, 1-3 parts of eggs, 0.3-0.5 parts of chicken essence, 1-1.2 parts of yeast powder, 1.2-1.5 parts of hydroxypropyl cellulose and 0.2-0.3 parts of carrageenan.

[0008] Furthermore, the blood tofu is prepared by crushing and steaming the main raw materials, adding yeast for fermentation, mixing with auxiliary materials, and adding a composite liquid formed by hydroxypropyl cellulose and carrageenan. The composite liquid is prepared by heating purified water to 50-60°C, adding hydroxypropyl cellulose and carrageenan in sequence while stirring at 60-80rpm, and then continuing stirring for 30-60 minutes.

[0009] The preparation method of the blood tofu is characterized by: tofu, duck blood, pork belly and bean dregs are crushed and mixed, cooled after steaming, yeast is added for fermentation, pepper powder, chili powder, salt, vegetable oil, eggs and chicken essence are added to the filter cake, a composite liquid prepared by hydroxypropyl cellulose and carrageenan is added under mixing and stirring, and then pressed into shape.

[0010] Furthermore, the composite liquid is prepared by heating purified water to 50-60° C., adding hydroxypropyl cellulose and carrageenan in sequence while stirring at 60-80 rpm, and then continuing to stir for 30-60 minutes.

[0011] In the preparation process, since tofu is the main raw material, bean dregs, pork belly, etc. are added, the final product has a relatively obvious powdery and gritty feeling, and the tofu and other raw materials provide rich nutrients for the growth of microorganisms, which easily cause excessive microorganisms and accelerate deterioration. In the present invention, yeast fermentation is used to make the mixture of tofu, duck blood, bean dregs and pork belly more expanded and soft, with a delicate taste. In the fermentation process, a wine flavor is produced, which has the effect of antiseptic and sterilization.

[0012] Tofu mainly contains protein, and lacks ingredients such as cellulose and polysaccharides. Cellulose can increase gastrointestinal motility and aid digestion. Bean dregs are rich in cellulose, polysaccharides and other ingredients, which enrich the nutritional composition of blood tofu. The rich polysaccharides also provide nutrition for yeast fermentation.

[0013] During the preparation process, since tofu is the main raw material, and raw materials such as bean dregs with a rough taste are added, the overall viscosity is poor, it is not easy to form after drying, it is easy to crack, and the product has a more obvious powdery and gritty feeling. In addition, blood tofu itself is prone to water loss, which leads to cracking and hard taste. After fermentation with yeast, the pores in the blood tofu increase and the permeability increases. When it comes into contact with air, the water loss in the blood tofu accelerates. After being stored for a period of time, the taste becomes worse.

[0014] In the present invention, hydroxypropyl cellulose and carrageenan are mixed at a certain temperature to form a jelly-like composite liquid, and the fermented raw material mixture is finally added. On the one hand, the grit and powdery texture of the blood tofu are further degraded on the basis of fermentation. On the other hand, the large pores formed by yeast fermentation provide space for the infiltration of the composite liquid, which penetrates the inside of the blood tofu, so that the blood tofu has sufficient viscosity. At the same time, the composite liquid forms a film wrapping, which effectively blocks the moisture generated by the yeast fermentation inside the blood tofu, inhibits the blood tofu from drying and hardening, and ensures the freshness of the taste.

[0015] Furthermore, the mass ratio of hydroxypropyl cellulose, carrageenan and purified water is 1.2-1.5:0.2-0.3:10.

[0016] Furthermore, the mixing and stirring speed is 10-12 rpm, and after adding the composite liquid, stirring is continued for 5-10 minutes, and then allowed to stand for 24-36 hours.

[0017] The most specific method for preparing blood tofu is characterized by following the steps:

[0018] Step 1:

[0019] (1) According to weight, 40-42 parts of tofu, 5-7 parts of duck blood, 7-9 parts of pork belly and 5-6 parts of bean dregs are crushed and mixed to form a mixture, steamed for 1-2 hours, and cooled for later use;

[0020] (2) Add 1-2 parts of yeast powder to the cooled mixture, mix well, place at 35-38° C. for 36-48 hours, and filter to obtain a filter cake;

[0021] (3) Add 0.5-0.8 parts of pepper, 1-2 parts of chili, 5-5.5 parts of vegetable oil, 5-5.5 parts of salt, 1-3 parts of eggs, and 0.3-0.5 parts of chicken stock to the filter cake and mix well;

[0022] Step 2: Take 10 parts of purified water and heat it to 50-60°C, add 1.2-1.5 parts of hydroxypropyl cellulose and 0.2-0.3 parts of carrageenan in sequence while stirring at 60-80 rpm, and continue stirring for 30-60 minutes after the addition is completed to obtain a composite solution;

[0023] Step 3: Add the composite liquid prepared in step 2 to the mixture prepared in step 1 at 10-12 rpm, and continue stirring for 5-10 minutes, then let it stand for 24-36 hours, press it into shape, and dry it until the moisture content is less than 15%.

[0024] The present invention has the following technical effects:

[0025] The blood tofu prepared by the preparation method of the present invention can lock the internal water of the blood tofu well to prevent it from being lost, the structure is stable without cracking, the shape does not fall apart when cut after long-term storage, the taste is delicate and soft, without powdery texture and grittiness, and the shelf life is as long as 12 months without adding preservatives, and the overall taste is fresh and the texture is elastic. DETAILED DESCRIPTION

[0026] The present invention is described in detail below through examples. It is necessary to point out that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above-mentioned contents of the present invention.

[0027] Example 1

[0028] A method for preparing blood tofu is carried out according to the following steps:

[0029] Step 1:

[0030] (1) According to weight, 40 parts of tofu with a water content of 80-85%, 6 parts of duck blood, 8 parts of pork belly and 5 parts of bean dregs are crushed and mixed to form a mixture, steamed for 1-2 hours, and cooled for later use;

[0031] (2) Add 2 parts of yeast powder to the cooled mixture, mix well, place at 35-38°C for 48 hours, and filter to obtain a filter cake;

[0032] (3) Add 0.6 parts of pepper, 1.5 parts of chili, 5 parts of vegetable oil, 5 parts of salt, 2 parts of eggs, and 0.4 parts of chicken stock to the filter cake and mix well;

[0033] Step 2: Take 10 parts of purified water and heat it to 55°C, add 1.5 parts of hydroxypropyl cellulose and 0.2 parts of carrageenan in sequence while stirring at 70 rpm, and continue stirring for 40 minutes after the addition is completed to obtain a composite solution;

[0034] Step 3: Add the composite liquid prepared in step 2 to the mixture prepared in step 1 at 10 rpm, and continue stirring for 8 minutes, then let it stand for 30 hours, press it into shape, and dry it. The moisture content is 12.94%.

[0035] Comparative Example 1:

[0036] A method for preparing blood tofu is carried out according to the following steps:

[0037] Step 1:

[0038] (1) According to weight, 40 parts of tofu with a water content of 80-85%, 6 parts of duck blood, 8 parts of pork belly and 5 parts of bean dregs are crushed and mixed to form a mixture, steamed for 1.5 hours, and cooled for later use;

[0039] (2) Add 0.6 parts of pepper, 1.5 parts of chili, 5 parts of vegetable oil, 5 parts of salt, 2 parts of eggs, and 0.4 parts of chicken stock to the filter cake and mix well;

[0040] Step 2: Take 10 parts of purified water and heat it to 55°C, add 1.5 parts of hydroxypropyl cellulose and 0.2 parts of carrageenan in sequence while stirring at 70 rpm, and continue stirring for 40 minutes after the addition is completed to obtain a composite solution;

[0041] Step 3: Add the composite liquid prepared in step 2 to the mixture prepared in step 1 at 10 rpm, and continue stirring for 8 minutes, then let it stand for 30 hours, press it into shape, and dry it. The moisture content is 12.87%.

[0042] Compared with Example 1, yeast was not used for fermentation in this solution. It was brown in shape, slightly elastic in taste, and had no powdery or gritty feel.

[0043] Comparative Example 2:

[0044] A method for preparing blood tofu is carried out according to the following steps:

[0045] Step 1:

[0046] (1) According to weight, 40 parts of tofu with a water content of 80-85%, 6 parts of duck blood, 8 parts of pork belly and 5 parts of bean dregs are crushed and mixed to form a mixture, steamed for 1-2 hours, and cooled for later use;

[0047] (2) Add 2 parts of yeast powder to the cooled mixture, mix well, place at 35-38°C for 48 hours, and filter to obtain a filter cake;

[0048] (3) Add 0.6 parts of pepper, 1.5 parts of chili, 5 parts of vegetable oil, 5 parts of salt, 2 parts of eggs, and 0.4 parts of chicken stock to the filter cake and mix well;

[0049] Step 2: The mixture obtained in step 1 was stirred at 10 rpm for 8 minutes, then allowed to stand for 30 hours, pressed into shape, and dried. The moisture content was 12.91%.

[0050] Compared with Example 1, hydroxypropyl cellulose and carrageenan are not added in this solution. The product is brown in color, slightly elastic in texture, and has a distinct powdery and gritty taste.

[0051] Comparative Example 3:

[0052] A method for preparing blood tofu is carried out according to the following steps:

[0053] Step 1:

[0054] (1) According to weight, 40 parts of tofu with a water content of 80-85%, 6 parts of duck blood, 8 parts of pork belly and 5 parts of bean dregs are crushed and mixed to form a mixture, steamed for 1-2 hours, and cooled for later use;

[0055] (2) Add 2 parts of yeast powder to the cooled mixture, mix well, place at 35-38°C for 48 hours, and filter to obtain a filter cake;

[0056] (3) Add 0.6 parts of pepper, 1.5 parts of chili, 5 parts of vegetable oil, 5 parts of salt, 2 parts of eggs, and 0.4 parts of chicken stock to the filter cake and mix well;

[0057] Step 2: Add hydroxypropyl cellulose and 0.2 parts of carrageenan to the mixture prepared in step 1 at 10 rpm, and continue stirring for 8 minutes, then let it stand for 30 hours, press it into shape, and dry it. The moisture content is 13.06%.

[0058] Compared with Example 1, in this solution, hydroxypropyl cellulose and carrageenan are directly added without first preparing a composite liquid. The product is brown in color, has a moderate hardness and a distinct powdery and gritty taste.

[0059] A blood tofu prepared by the same scheme as Example 3 without yeast fermentation and without adding any hydroxypropyl cellulose and carrageenan was used as a control (initial moisture content was 13.19%). The blood tofu prepared in Example 1 and Comparative Examples 1-3 were placed at room temperature, and the quality of the blood tofu was judged as a whole by observing its structural changes, shape and taste, and detecting its moisture content, microbial limit and other parameters. The changes in various indicators over time are shown in Table 1.

[0060] Table 1:

[0061]

[0062] As can be seen from the above table, the blood tofu (control group) prepared by the conventional method has a water content of 10.26% at 3 months, 5.28% at 12 months, and the microbial limit exceeds the standard at 6 months. Compared with the control group, the specific composite liquid formed by hydroxypropyl cellulose and carrageenan is added in Comparative Example 1, which effectively inhibits the loss of water. Compared with the control group, the yeast fermentation step is added in Comparative Example 2, but the water loss in the finished blood tofu is obviously faster, and the water content is only 4.08% at 12 months. Although hydroxypropyl cellulose and carrageenan are also added in Comparative Example 2, the water content in the blood tofu is not effectively blocked, and the water content is also reduced to 7.69% at 12 months. In Example 1, the water content in the blood tofu is effectively inhibited from decreasing, and the powdery and gritty feeling is reduced. After 12 months of storage, the overall taste is fresh, the texture is elastic, and no deterioration occurs.

[0063] Example 2

[0064] A method for preparing blood tofu is carried out according to the following steps:

[0065] Step 1:

[0066] (1) According to weight, 40 parts of tofu with a water content of 80-85%, 5 parts of duck blood, 9 parts of pork belly and 5 parts of bean curd dregs are crushed and mixed to form a mixture, steamed for 1 hour, and cooled for later use;

[0067] (2) Add 2 parts of yeast powder to the cooled mixture, mix well, place at 35-38°C for 36 hours, and filter to obtain a filter cake;

[0068] (3) Add 0.8 parts of pepper, 2 parts of chili, 5.5 parts of vegetable oil, 5.5 parts of salt, 3 parts of eggs, and 0.3 parts of chicken stock to the filter cake and mix well;

[0069] Step 2: Take 10 parts of purified water and heat it to 50°C, add 1.5 parts of hydroxypropyl cellulose and 0.2 parts of carrageenan in sequence while stirring at 80 rpm, and continue stirring for 30 minutes after the addition is completed to obtain a composite solution;

[0070] Step 3: Add the composite liquid prepared in step 2 to the mixture prepared in step 1 at 10 rpm, and continue stirring for 10 minutes, then let it stand for 24 hours, press it into shape, and dry it. The moisture content is 14.14%.

[0071] The changes in indicators of the blood tofu prepared in Example 2 during the storage process are shown in Table 2.

[0072] Table 2:

[0073]

[0074] Example 3

[0075] A method for preparing blood tofu is carried out according to the following steps:

[0076] Step 1:

[0077] (1) According to weight, 42 parts of tofu with a water content of 80-85%, 7 parts of duck blood, 7 parts of pork belly and 6 parts of bean dregs are crushed and mixed to form a mixture, steamed for 2 hours, and cooled for later use;

[0078] (2) Add 1 part of yeast powder to the cooled mixture, mix well, place at 35-38°C for 48 hours, and filter to obtain a filter cake;

[0079] (3) Add 0.5 parts of pepper, 1 part of chili, 5 parts of vegetable oil, 5 parts of salt, 1 part of egg, and 0.5 parts of chicken stock to the filter cake and mix well;

[0080] Step 2: Take 10 parts of purified water and heat it to 60°C, add 1.2 parts of hydroxypropyl cellulose and 0.3 parts of carrageenan in sequence while stirring at 60 rpm, and continue stirring for 60 minutes after the addition is completed to obtain a composite solution;

[0081] Step 3: Add the composite liquid prepared in step 2 to the mixture prepared in step 1 at 12 rpm, and continue stirring for 5 minutes, then let it stand for 36 hours, press it into shape, and dry it. The moisture content is 13.17%.

[0082] The changes in indicators of the blood tofu prepared in Example 3 during the storage process are shown in Table 3.

[0083] Table 3:

[0084]

[0085] It can be seen that the addition of the specific composite liquid formed by hydroxypropyl cellulose and carrageenan forms deep penetration in the pores formed by yeast fermentation, which increases the viscosity of the system and at the same time forms a wrapping around the system, effectively inhibiting the loss of water. Through the combination of fermentation and composite liquid, the powdery and gritty feel of the blood tofu is reduced in two steps, and at the same time, the deterioration of the blood tofu is greatly inhibited, effectively extending its shelf life.

Claims

1. A method for preparing blood tofu, characterized in that: The tofu, duck blood, pork belly and bean dregs are crushed and mixed, steamed and cooled, yeast is added for fermentation, and the filter cake is filtered and added with pepper powder, chili powder, salt, vegetable oil, eggs and chicken essence. A composite liquid prepared by hydroxypropyl cellulose and carrageenan is added under mixing and stirring, and then pressed into shape. The amount of each material is calculated by mass as follows: 40-42 parts of tofu, 5-7 parts of duck blood, 7-9 parts of pork belly, 5-6 parts of bean dregs, 5-5.5 parts of vegetable oil, 0.5-0.8 parts of pepper powder, 1-2 parts of chili powder, 5-5.5 parts of salt, 1-3 parts of eggs, 0.3-0.5 parts of chicken essence, 1-1.2 parts of yeast powder, 1.2-1.5 parts of hydroxypropyl cellulose and 0.2-0.3 parts of carrageenan. The composite liquid is specifically prepared by heating purified water to 50-60°C, adding hydroxypropyl cellulose and carrageenan in sequence while stirring at 60-80rpm, and then continuing to stir for 30-60min.

2. The method for preparing blood tofu according to claim 1, characterized in that: The mixing and stirring speed is 10-12 rpm. After adding the composite liquid, stirring is continued for 5-10 minutes, and then allowed to stand for 24-36 hours.

3. A method for preparing blood tofu, characterized in that: Proceed as follows: Step 1: (1) According to weight, 40-42 parts of tofu, 5-7 parts of duck blood, 7-9 parts of pork belly and 5-6 parts of bean dregs are crushed and mixed to form a mixture, steamed for 1-2 hours, and cooled for later use; (2) Add 1-2 parts of yeast powder to the cooled mixture, mix well, place at 35-38°C for 36-48 hours, and filter to obtain a filter cake; (3) Add 0.5-0.8 parts of Sichuan pepper, 1-2 parts of chili pepper, 5-5.5 parts of vegetable oil, 5-5.5 parts of salt, 1-3 parts of eggs, and 0.3-0.5 parts of chicken stock to the filter cake and mix well; Step 2: Heat purified water to 50-60°C, add 1.2-1.5 parts of hydroxypropyl cellulose and 0.2-0.3 parts of carrageenan in sequence while stirring at 60-80 rpm, and continue stirring for 30-60 minutes after the addition is completed to obtain a composite solution; Step 3: Add the composite liquid prepared in step 2 to the mixture prepared in step 1 at 10-12 rpm, and continue stirring for 5-10 minutes, then let it stand for 24-36 hours, press it into shape, and dry it until the moisture content is less than 15%.

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