Preparation method of tempeh with effects of reducing blood sugar and preventing thrombus

Abstract

The invention discloses a preparation method of tempeh with effects of reducing blood sugar and preventing thrombus, and relates to the technical field of tempeh preparation. The preparation method of tempeh comprises the following steps: (1) soybean detoxification; (2) peeling; (3) soaking; (4) steaming: steaming the soaked soybeans, after steaming, continuously steaming for 5-10 minutes by using an acetic acid aqueous solution with the mass concentration of 5-10%, taking out and cooling, and controlling the water content until the water content is 40-60%; and (5) performing fermentation: inoculating 0.2-0.7% of a rhizopus oligosporus leavening agent into the cooked soybeans, and performing fermentation at 15-35 DEG C for 1-3 days so as to obtain the fermented soybeans. The tempeh prepared by the preparation method disclosed by the invention has remarkable effects of resisting thrombus and reducing blood sugar, and is long in shelf life, rich in fragrance level and good in product quality.

Description

Technical Field

[0001] The present invention relates to the technical field of tempeh preparation, and particularly relates to a preparation method of tempeh with hypoglycemic and thrombus-preventing effects. Background Art

[0002] Tempeh is a white cake-like food made from soybeans as the main raw material through processes of peeling, soaking, steaming, and fermentation. It is a fermented soy product with local characteristics that evolved after China's bean fermentation technology was introduced into Indonesia and took root in the local environment and food culture. Tempeh is rich in nutrients such as protein, amino acids, fat, vitamins, and minerals, as well as active ingredients such as isoflavones and thrombolytic kinases. Among them, thrombolytic kinases have the effect of dissolving thrombi, and regular consumption can prevent the occurrence of thrombus diseases. Indonesians regard tempeh as a "substitute for meat" and have long been favored by people in Southeast Asia. It is the only fermented soy product used as a staple food in the world.

[0003] Currently, the tempeh on the market has the following problems: (1) The content of thrombolytic kinases in tempeh is not high, and the hypoglycemic and thrombus-preventing effects are not significant. The product quality is uneven, affecting the use effect of consumers. (2) The stability of tempeh products is not high enough. The finished products are easily contaminated by miscellaneous bacteria and have a short shelf life. Under refrigeration conditions (0 - 4°C), the shelf life of vacuum-packed tempeh does not exceed 1 month and can only be stored for 1 - 3 weeks at most. For fresh tempeh after opening the package, under refrigerator preservation conditions, the freshness can usually only be maintained for 2 - 3 days, and then the fresh flavor fades. (3) The pleasant fragrance in tempeh is relatively light, and its unique fermentation flavor is not easily accepted by the people in our country.

[0004] Therefore, the purpose of the present invention is to provide a preparation method of tempeh with hypoglycemic and thrombus-preventing effects to solve the above problems. Summary of the Invention

[0005] In view of the above deficiencies, the present invention provides a preparation method of tempeh with hypoglycemic and thrombus-preventing effects, which solves the problems of low content of thrombolytic kinases, short shelf life, and relatively light fragrance in existing tempeh. The specific technical solutions are as follows:

[0006] A preparation method of tempeh with hypoglycemic and thrombus-preventing effects, comprising the following steps:

[0007] (1) Soybean detoxification: After polishing, freeze-thaw treatment, and spraying acidified water mist on whole soybeans, put them into a distillation tank. First, introduce steam, carry out pressure detoxification distillation, then reduce to normal pressure, introduce a mixed vapor of ethanol and water, carry out micro-pressure detoxification distillation, then reduce to normal pressure again, continue to introduce a mixed vapor of acetic acid and water, carry out micro-pressure detoxification distillation, and finally reduce to normal pressure, introduce a mixed vapor of ethanol and water for detoxification distillation, and then reduce the pressure to obtain detoxified soybeans;

[0008] (2) Peeling: Carry out peeling treatment on the detoxified soybeans;

[0009] (3) Soaking: Soak the peeled soybeans.

[0010] (4) Steaming: Steam the soaked soybeans. After steaming, continue to steam with an acetic acid aqueous solution with a mass concentration of 5 - 10% for 5 - 10 min, take out and cool, drain the water until the water content is 40 - 60% to obtain steamed soybeans.

[0011] (5) Fermentation: After piling up the steamed soybeans to a thickness of 2 - 5 cm, inoculate 0.2 - 0.7% of Rhizopus oligosporus starter into the steamed soybeans, and ferment at 15 - 35°C for 1 - 3 days to obtain the tempeh.

[0012] Preferably, in step (1), the detoxification of the soybeans is as follows: Polish the whole soybeans, then perform freeze-thaw treatment to obtain pretreated soybeans. Spray acidified water mist on the pretreated soybeans, control the temperature at 35 - 37°C, and treat for 80 - 90 min to obtain first-stage treated soybeans. Put the first-stage treated soybeans into a distillation tank. The distillation tank is connected to an evaporator. First, add water with the same weight as the first-stage treated soybeans to the evaporator, then introduce steam into the distillation tank, and perform detoxification distillation under pressurized conditions for 1 - 5 min. Then reduce the pressure to normal pressure, and add an ethanol solution with a weight of 1 - 2% of the first-stage treated soybeans to the evaporator, continue to introduce mixed steam, and perform detoxification distillation under slightly pressurized conditions for 1 - 5 min. Then reduce the pressure to normal pressure, and add an acetic acid solution with a weight of 0.01 - 2% of the first-stage treated soybeans to the evaporator, continue to introduce mixed steam, and perform detoxification distillation under slightly pressurized conditions for 5 - 10 min. Finally, reduce the pressure to normal pressure, add an ethanol solution with a weight of 0.001 - 0.015% of the first-stage treated soybeans to the evaporator, introduce mixed steam for detoxification distillation for 1 - 2 min, and then perform depressurization treatment for 3 - 5 min to obtain the product.

[0013] Preferably, the freeze-thaw treatment is as follows: First, place the dry whole soybeans in a cold storage at -5°C to -20°C for 10 - 12 h, then take them out and place them at room temperature to thaw for 3 - 5 h. Then continue with refrigeration and thawing, and repeat 2 - 3 times.

[0014] Preferably, the acidified water mist is made by adjusting the pH of water to 5 - 6 with acetic acid.

[0015] Preferably, the pressure for pressurization is 0.1 - 5 MPa; the pressure for slight pressurization is 0.001 - 0.005 MPa; the pressure for depressurization is -0.05 - -0.02 MPa.

[0016] Preferably, the mass concentration of the ethanol solution is 40 - 60%; the mass concentration of the acetic acid solution is 1 - 3%.

[0017] Preferably, in step (3), the soaking time is 8 - 12 h.

[0018] Preferably, in step (5), the preparation method of the Rhizopus oligosporus fermenting agent is as follows: Mix 20 - 30 parts of soybean powder, 1 - 3 parts of milk fat, 4 - 9 parts of glucose and 15 - 20 parts of water, and perform high-temperature sterilization to obtain a fermentation substrate. Add 1 - 5% of an organic acid based on the weight of the fermentation substrate to the fermentation substrate, mix well, inoculate 0.1 - 0.5% of Rhizopus oligosporus based on the weight of the fermentation substrate, ferment at 20 - 28°C for 1 - 2 days, and perform low-temperature drying to obtain the Rhizopus oligosporus fermenting agent.

[0019] Preferably, the organic acid is one of malic acid, acetic acid or citric acid.

[0020] Preferably, the low-temperature drying is performed at 4 - 8°C until the water content is 20 - 30%.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] 1. The present invention first detoxifies soybeans and then uses them for fermenting to make tempeh, which can make the content of thrombolytic kinase in the obtained tempeh higher. After detection, the content of thrombolytic kinase in the tempeh prepared by the method of the present invention is about 6000 FU / g, which is 6 - 7 times higher than that of the tempeh prepared by the traditional method. The tempeh prepared by the method of the present invention has significant blood sugar-lowering and thrombolytic effects, and the product quality is high.

[0023] 2. After the soybeans are steamed in the present invention, they are further steamed with an acetic acid aqueous solution, which can improve the stability of the finished tempeh, make the finished tempeh not easily contaminated by miscellaneous bacteria, and have a longer shelf life. After detection, under refrigeration conditions (0 - 4°C), the shelf life of vacuum-packed tempeh is about 2 months, and the fresh tempeh after opening the package can maintain its freshness for 6 - 7 days under the refrigerator preservation conditions.

[0024] 3. The present invention uses a Rhizopus oligosporus fermenting agent for inoculation, which can make the obtained tempeh have pleasant flavor substances and improve people's acceptance of tempeh. Among them, the Rhizopus oligosporus fermenting agent is obtained by culturing Rhizopus oligosporus with soybean powder, milk fat and glucose as the culture medium. This culture medium can stimulate the strain to synthesize a large amount of lipase, promote the decomposition of soybean fat, and produce more pleasant flavor substances. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for description in the embodiments.

[0026] Figure 1 It is a bar chart of the experimental results of the antithrombotic effect of the tempeh prepared by the present invention;

[0027] Figure 2 Bar graph of the experimental results of the hypoglycemic effect of tempeh prepared by the present invention. Detailed Description of the Invention

[0028] The following is a detailed description of the specific embodiments of the present invention, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0029] The strain number of Rhizopus oligosporus used in the following examples and comparative examples is ATCC46348.

[0030] Example 1

[0031] A method for preparing tempeh with hypoglycemic and antithrombotic effects, comprising the following steps:

[0032] (1) Soybean detoxification: Polish the whole soybeans, then perform freeze-thaw treatment to obtain pretreated soybeans. Spray acidified water mist on the pretreated soybeans. The acidified water mist is made by adjusting the pH of water to 5 with acetic acid. Control the temperature at 35 °C and treat for 90 min to obtain first-stage treated soybeans. Put the first-stage treated soybeans into a distillation tank. The distillation tank is connected to an evaporator. First, add water with the same weight as the first-stage treated soybeans to the evaporator, then introduce steam into the distillation tank, and perform detoxification distillation for 5 min under a pressurized condition of 0.1 MPa. Then reduce the pressure to normal pressure, and add an ethanol solution with a mass concentration of 60% and a weight of 1% of the first-stage treated soybeans to the evaporator, continue to introduce mixed steam, and perform detoxification distillation for 5 min under a micro-pressure condition of 0.001 MPa. Then reduce the pressure to normal pressure, and add an acetic acid solution with a mass concentration of 3% and a weight of 0.01% of the first-stage treated soybeans to the evaporator, continue to introduce mixed steam, and perform detoxification distillation for 10 min under a micro-pressure condition of 0.001 MPa. Finally, reduce the pressure to normal pressure, add an ethanol solution with a mass concentration of 60% and a weight of 0.001% of the first-stage treated soybeans to the evaporator, introduce mixed steam for detoxification distillation for 1 min, and then perform decompression treatment for 5 min under a pressure condition of -0.05 MPa to obtain detoxified soybeans;

[0033] The freeze-thaw treatment is as follows: First, place the dry whole soybeans in a cold storage at -5 °C for 12 h, then take them out and place them at room temperature for 3 h to thaw. Then continue with refrigeration and thawing, repeating 2 times.

[0034] (2) Skin removal: Use a peeling machine to remove the skin of the detoxified soybeans;

[0035] (3) Soaking: Soak the skinned soybeans for 8 h;

[0036] (4) Steaming: Steam the soaked soybeans. After steaming, continue to steam with an acetic acid aqueous solution with a mass concentration of 5% for 10 min, take them out and cool, and control the water content to 40% by draining water to obtain steamed soybeans;

[0037] (5) Fermentation: After piling up the cooked soybeans to a thickness of 2 cm, inoculate the cooked soybeans with 0.2% of the Rhizopus oligosporus starter, and ferment at 15 °C for 3 days to obtain the tempeh.

[0038] The preparation method of the Rhizopus oligosporus starter is as follows: Mix 20 parts of soybean powder, 1 part of milk fat, 4 parts of glucose and 15 parts of water, and then sterilize at high temperature to obtain the fermentation substrate. After adding 1% of malic acid based on the weight of the fermentation substrate to the fermentation substrate and mixing evenly, inoculate 0.1% of Rhizopus oligosporus based on the weight of the fermentation substrate, ferment at 20 °C for 2 days, and dry at low temperature at 4 °C until the water content is 20% to obtain it.

[0039] Example 2

[0040] A preparation method of tempeh with hypoglycemic and antithrombotic effects, comprising the following steps:

[0041] (1) Soybean detoxification: Polish the whole soybeans, then perform freeze-thaw treatment to obtain pretreated soybeans. Spray acidified water mist on the pretreated soybeans. The acidified water mist is made by adjusting the pH of water to 6 with acetic acid. Control the temperature at 37 °C and treat for 80 min to obtain first-stage treated soybeans. Put the first-stage treated soybeans into a distillation tank. The distillation tank is connected to an evaporator. First, add water with the same weight as the first-stage treated soybeans to the evaporator, then introduce steam into the distillation tank, and perform detoxification distillation for 1 min under a pressurized condition of 5 MPa. Then reduce the pressure to normal pressure, and add an ethanol solution with a mass concentration of 40% and a weight of 2% of the first-stage treated soybeans to the evaporator, continue to introduce mixed steam, and perform detoxification distillation for 1 min under a micro-pressurized condition of 0.005 MPa. Then reduce the pressure to normal pressure, and add an acetic acid solution with a mass concentration of 1% and a weight of 2% of the first-stage treated soybeans to the evaporator, continue to introduce mixed steam, and perform detoxification distillation for 5 min under a micro-pressurized condition of 0.005 MPa. Finally, reduce the pressure to normal pressure, add an ethanol solution with a mass concentration of 40% and a weight of 0.015% of the first-stage treated soybeans to the evaporator, introduce mixed steam for detoxification distillation for 1 min, and then perform depressurization treatment for 3 min under a pressure condition of -0.02 MPa to obtain detoxified soybeans;

[0042] The freeze-thaw treatment is as follows: First, place the dry whole soybeans in a cold storage at -20 °C for 10 h, then take them out and place them at room temperature for 5 h to thaw, and then continue refrigeration and thawing, repeating 3 times.

[0043] (2) Peeling: Use a peeling machine to peel the detoxified soybeans.

[0044] (3) Soaking: Soak the peeled soybeans for 12 h.

[0045] (4) Steaming: Steam the soaked soybeans. After steaming, continue to steam with an aqueous acetic acid solution with a mass concentration of 10% for 5 minutes, take out and cool, drain the water until the water content is 60% to obtain steamed soybeans;

[0046] (5) Fermentation: Stack the steamed soybeans to a thickness of 5 cm, inoculate with 0.7% of the weight of the steamed soybeans of Rhizopus oligosporus fermenting agent, and ferment at 35°C for 1 day to obtain the tempeh.

[0047] The preparation method of the Rhizopus oligosporus fermenting agent is as follows: Mix 30 parts of soybean powder, 3 parts of milk fat, 9 parts of glucose and 20 parts of water, sterilize at high temperature to obtain a fermentation substrate, add 5% of the weight of the fermentation substrate of acetic acid to the fermentation substrate and mix evenly, inoculate 0.5% of the weight of the fermentation substrate of Rhizopus oligosporus, ferment at 28°C for 1 day, and dry at low temperature at 8°C until the water content is 30% to obtain it.

[0048] Example 3

[0049] A preparation method of tempeh with hypoglycemic and antithrombotic effects, comprising the following steps:

[0050] (1) Detoxification of soybeans: Polish the whole soybeans, then perform freeze-thaw treatment to obtain pretreated soybeans. Spray acidified water mist on the pretreated soybeans. The acidified water mist is made by adjusting the pH of water to 6 with acetic acid. Control the temperature at 36°C and process for 85 minutes to obtain first-stage treated soybeans; Put the first-stage treated soybeans into a distillation tank. The distillation tank is connected to an evaporator. First, add water with the same weight as the first-stage treated soybeans to the evaporator, then introduce steam into the distillation tank, and perform detoxification distillation for 2 minutes under a pressurized condition of 2 MPa; Then reduce to normal pressure, and add an ethanol solution with a mass concentration of 50% and 1.5% of the weight of the first-stage treated soybeans to the evaporator, continue to introduce mixed steam, and perform detoxification distillation for 3 minutes under a micro-pressure condition of 0.003 MPa; Then reduce to normal pressure, and add an acetic acid solution with a mass concentration of 2% and 1% of the weight of the first-stage treated soybeans to the evaporator, continue to introduce mixed steam, and perform detoxification distillation for 7 minutes under a micro-pressure condition of 0.003 MPa; Finally, reduce to normal pressure, add an ethanol solution with a mass concentration of 50% and 0.009% of the weight of the first-stage treated soybeans to the evaporator, introduce mixed steam for detoxification distillation for 2 minutes, and then perform decompression treatment for 4 minutes under a pressure condition of -0.04 MPa to obtain detoxified soybeans;

[0051] The freeze-thaw treatment is as follows: First, place the dry whole soybeans in a cold storage at -10°C for 10 hours, then take them out and place them at room temperature to thaw for 4 hours, then continue refrigeration and thawing, repeating 3 times.

[0052] (2) Peeling: Use a peeling machine to peel the detoxified soybeans;

[0053] (3) Soaking: Soak the peeled soybeans for 10 h;

[0054] (4) Steaming: Steam the soaked soybeans. After steaming, continue to steam with an acetic acid aqueous solution with a mass concentration of 6% for 6 min, take out and cool, and control the water content to 50% to obtain steamed soybeans;

[0055] (5) Fermentation: After piling up the steamed soybeans to a thickness of 3 cm, inoculate 0.5% of the weight of the steamed soybeans with Rhizopus oligosporus starter, and ferment at 28 °C for 2 days to obtain the tempeh.

[0056] The preparation method of the Rhizopus oligosporus starter is as follows: Mix 25 parts of soybean powder, 2 parts of milk fat, 5 parts of glucose and 18 parts of water, and sterilize at high temperature to obtain a fermentation substrate. Add 4% of the weight of the fermentation substrate of citric acid to the fermentation substrate and mix well, then inoculate 0.2% of the weight of the fermentation substrate with Rhizopus oligosporus, ferment at 22 °C for 2 days, and dry at low temperature at 4 °C until the water content is 25% to obtain it.

[0057] Comparative Example 1: The preparation method of the tempeh in this comparative example is the traditional preparation method, that is, first use a peeling machine to peel the soybeans, soak the peeled soybeans for 8 h and then steam them, control the water content to 30% to obtain steamed soybeans; after piling up the steamed soybeans to a thickness of 2 cm, inoculate 0.2% of the weight of the steamed soybeans with Rhizopus oligosporus, and ferment at 28 °C for 2 days to obtain the tempeh.

[0058] Use the enzyme-linked immunosorbent assay (ELISA) to detect the content of thrombolytic kinase in the tempeh of Example 1, Example 2, Example 3 and Comparative Example 1 respectively. The results are shown in Table 1:

[0059] Table 1

[0060]

[0061] Table 1 shows that the content of thrombolytic kinase in the tempeh prepared by the method of the present invention is about 6000 FU / g, which is 6-7 times higher than that of the tempeh prepared by the traditional method.

[0062] Thrombolytic effect test of the tempeh of the present invention:

[0063] The applicant uses the tempeh prepared in Example 1 for the anti-thrombosis efficacy test of zebrafish. The test method is as follows:

[0064] 1. Detection principle The genes of zebrafish have an 87% similarity with human genes, and there are many similarities between the blood systems of zebrafish and humans in terms of platelets and coagulation factors. A large dose of adrenaline (AH) can cause vascular endothelial damage and enhanced platelet activity in animals, resulting in a hypercoagulable state in the body. The significant increase in adrenaline mimics rage and anger in humans, leading to qi stagnation and blood stasis. The staining area of blood cells in the tails of zebrafish with thrombosis will increase significantly. The anti-thrombotic efficacy is evaluated by detecting the congestion area of the caudal vein of zebrafish.

[0065] 2. Materials and methods

[0066] 2.1 Experimental instruments and reagents

[0067] Stereo fluorescence microscope (SZX7, Olympus, Japan), adrenaline hydrochloride (CAS: 55-31-2), aspirin (CAS: 50-78-2)

[0068] 2.2 Detection system and sample size

[0069] Experimental system: Wild AB strain zebrafish

[0070] Zebrafish age: 3 days after fertilization

[0071] Sample size for each group of experiments: 30 per well, one well per group

[0072] 3. Experimental procedure

[0073] The tested zebrafish are divided into four groups: blank control group, model control group, positive control group, and sample treatment group. Among them, the blank control group is not treated with anything. The model control group, positive control group, and sample treatment group are all administered an equal amount of adrenaline hydrochloride. The positive control group and sample treatment group are respectively administered aspirin and the sample solution to be tested (solution prepared from tempeh obtained in Example 1) while ingesting adrenaline hydrochloride. After culturing for a period of time, the staining area of blood cells in the tails of zebrafish in different groups is detected and analyzed under a microscope.

[0074] 4. Judgment basis

[0075] On the basis that the test meets the effectiveness, compared with the blank control group, the staining area of blood cells in the tail of the model control group increases significantly (P < 0.05), indicating that the modeling is successful. Compared with the model control group, the staining area of blood cells in the tail of the sample test group decreases significantly and P < 0.05, indicating that the sample has anti-thrombotic efficacy.

[0076] 5. Detection results

[0077] The sample group at a concentration of 100 μg / mL showed no significant difference compared with the blank control group. Therefore, 100 μg / mL is the maximum safe concentration. The test results are shown in Table 2 and Figure 1 .

[0078] Table 2 Results of the stained area of tail blood cells (pixels)

[0079] Blank control group Model control group Positive control group Sample treatment group 9451.67±2426.23 30677.33±13989.03 15976±7082.5 15182.67±5259.77

[0080] From Table 2 and Figure 1 it can be seen that the tempeh prepared by the method of the present invention has a significant antithrombotic effect (P < 0.01).

[0081] Hypoglycemic effect test of tempeh of the present invention:

[0082] The applicant used the tempeh prepared in Example 1 to conduct a hypoglycemic efficacy test on zebrafish. The test method is as follows:

[0083] 1. Detection principle

[0084] There are certain similarities between zebrafish and humans in terms of glucose metabolism. When zebrafish are given a high-sugar environment, the blood glucose regulation mechanism in their bodies will face challenges. A large amount of sugar intake will exceed the normal glucose uptake and utilization ability of zebrafish. Under normal circumstances, cells take up glucose through the insulin-mediated signaling pathway and use it for energy production or convert it into glycogen for storage. However, under high-sugar conditions, excessive glucose will lead to an increase in insulin secretion, but long-term high-sugar stimulation may reduce insulin sensitivity, that is, the response of cells to insulin weakens, resulting in reduced glucose uptake. In addition, the high-sugar environment may also damage pancreatic islet cells, affecting the synthesis and secretion of insulin, impairing the blood glucose regulation ability, and causing the blood glucose level to continue to rise, ultimately forming a hyperglycemic model. Positive drug metformin.

[0085] 2. Materials and methods

[0086] 2.1 Experimental instruments and reagents

[0087] Centrifuge, ultrasonic cell disruptor, Roche intelligent navigation blood glucose meter, glucose, metformin

[0088] 2.2 Detection system and sample size

[0089] Experimental system: Wild AB strain zebrafish

[0090] Zebrafish age: 1 day after fertilization

[0091] Sample size for each group of experiments: 30 per well, 1 well per group

[0092] 3. Experimental procedure

[0093] The zebrafish to be tested were divided into four groups: a normal control group, a model control group, a positive control group, and a sample treatment group. The normal control group was not given any treatment. A hyperglycemic environment was established in the model control group. Metformin was added to the positive control group while establishing the hyperglycemic environment. The sample to be tested (tempeh prepared in Example 1) was added to the sample treatment group while establishing the hyperglycemic environment. After culturing for a period of time, the four groups of zebrafish were crushed and centrifuged to obtain the supernatant, and the blood glucose was measured. The data analysis results of the four groups were compared.

[0094] 4. Criteria for judgment

[0095] On the basis that the test met the effectiveness requirements, compared with the blank control group, the blood glucose value in the model control group increased significantly (P < 0.05), indicating that the modeling was successful. Compared with the model control group, the blood glucose value in the sample treatment group decreased significantly (P < 0.05), indicating that the sample had the effect of assisting in reducing blood glucose.

[0096] 5. Test results

[0097] There was no significant difference between the sample group at a concentration of 100 μg / mL and the blank control group. Therefore, the concentration of 100 μg / mL was the maximum safe concentration. The test results are shown in Table 3 and Figure 2 :

[0098] Table 3 Blood glucose values of zebrafish (mmol / L)

[0099] Blank control group Model control group Positive control group Sample treatment group 1.13±0.05 7.40±0.08 2.07±0.05 2.27±0.05

[0100] From Table 3 and Figure 2 it can be seen that the tempeh prepared by the method of the present invention has a significant blood glucose-lowering effect (P < 0.001).

[0101] Comparative Example 2: Step (4) Steaming: The soaked soybeans were steamed. After steaming, they were taken out and cooled, and the water was controlled to a water content of 40% to obtain steamed soybeans; other steps were the same as in Example 1.

[0102] The shelf lives of the tempeh prepared in the test example, Example 2, Example 3, and Comparative Example 2 were detected, and the results are shown in Table 4. Among them, when the hyphal color darkened, there was a smell, and there was no umami taste, it was considered spoiled.

[0103] Table 4 Shelf lives of each group

[0104]

[0105]

[0106] Table 4 shows that after steaming soybeans, continued steaming with an aqueous acetic acid solution can improve the stability of the finished tempeh, making the finished tempeh less susceptible to contamination by miscellaneous bacteria and having a longer shelf life. Under refrigeration conditions (0 - 4°C), the shelf life of vacuum-packed tempeh is about 2 months. For freshly opened tempeh, it can maintain its freshness for 6 - 7 days under refrigerator preservation conditions, that is, when eaten at 6 - 7 days, it is still slightly sweet and slightly sour with a fresh taste.

[0107] Comparative Example 3: Step (5) Fermentation: After piling up the steamed soybeans to a thickness of 2 cm, inoculate Rhizopus oligosporus at 0.2% of the weight of the steamed soybeans and ferment at 15°C for 3 days to obtain the tempeh. Other steps are the same as those in Example 1.

[0108] The types of flavor substances in the tempeh prepared in Example 1, Example 2, Example 3 and Comparative Example 3 were detected by gas chromatography - mass spectrometry (GC - MS). The results show that Example 1, Example 2 and Example 3 all contain various flavor substances such as butyric acid, hexanoic acid, isoamyl alcohol, phenethyl alcohol, hexanal, diacetyl, 2,3 - butanedione, ethyl acetate and vanillin, while Comparative Example 3 does not contain diacetyl, 2,3 - butanedione, butyric acid and hexanoic acid. It can be seen that inoculating with Rhizopus oligosporus starter in the present invention can make the prepared tempeh have more pleasant flavor substances and improve people's acceptance of tempeh. This may be related to the fact that Rhizopus oligosporus starter can synthesize a large amount of lipase and promote the decomposition of soybean fat.

[0109] In summary, the tempeh prepared by the present invention has significant antithrombotic and hypoglycemic effects, a long shelf life, rich flavor levels and good product quality.

[0110] The foregoing description of specific exemplary embodiments of the invention has been presented for purposes of illustration and example. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many modifications and variations are possible in light of the above teaching. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the invention and its practical applications, so that those skilled in the art can implement and utilize the various different exemplary embodiments of the invention as well as various different selections and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A method for preparing tempeh with hypoglycemic and anti-thrombotic effects, characterized in that: The following steps are involved: (1) Soybean detoxification: Whole soybeans are polished, freeze-thawed, and sprayed with acidified water mist, and then placed in a distillation tank, and water vapor is first introduced to perform detoxification distillation under pressure, and then the pressure is reduced to normal pressure, and a mixed vapor of ethanol and water is introduced to perform detoxification distillation under micro-pressure, and then the pressure is reduced to normal pressure, and a mixed vapor of acetic acid and water is introduced to perform detoxification distillation under micro-pressure, and finally the pressure is reduced to normal pressure, and a mixed vapor of ethanol and water is introduced to perform detoxification distillation under decompression, thereby obtaining detoxified soybeans; (2) peeling: peeling the detoxified soybeans; (3) Soaking: Soaking the peeled soybeans; (4) Steaming: Steaming the soaked soybeans, and then steaming them for 5-10 minutes with an acetic acid aqueous solution having a mass concentration of 5-10%, taking them out, cooling them, and controlling the water content to 40-60%, thereby obtaining steamed soybeans; (5) Fermentation: inoculating 0.2-0.7% of oligosporus Rhizopus fermentation agent into the steamed soybeans, and fermenting at 15-35° C. for 1-3 days to obtain the tempeh.

2. The method for preparing tempeh with hypoglycemic and anti-thrombotic effects according to claim 1, characterized in that: In step (1), the soybean detoxification comprises: polishing the whole soybeans, and then performing freeze-thaw treatment to obtain pre-treated soybeans, spraying the pre-treated soybeans with acidified water mist, controlling the temperature to be 35-37°C, and treating for 80-90 minutes to obtain primary treated soybeans; placing the primary treated soybeans in a distillation tank, the distillation tank being connected to an evaporator, first adding water of the same weight as the primary treated soybeans to the evaporator, then passing water vapor into the distillation tank, and performing detoxification distillation under pressurized conditions for 1-5 minutes; then reducing the pressure to normal pressure, and adding the pre-treated soybeans to the evaporator. The ethanol solution of the primary treated soybeans is 1-2% by weight, and the mixed steam is continuously introduced, and the detoxification distillation is performed under micro-pressure conditions for 1-5 minutes; then the pressure is reduced to normal pressure, and an acetic acid solution of 0.01-2% by weight of the primary treated soybeans is added to the evaporator, and the mixed steam is continuously introduced, and the detoxification distillation is performed under micro-pressure conditions for 5-10 minutes; finally, the pressure is reduced to normal pressure, and an ethanol solution of 0.001-0.015% by weight of the primary treated soybeans is added to the evaporator, and the mixed steam is introduced for detoxification distillation for 1-2 minutes, and then the pressure is reduced for 3-5 minutes to obtain the product.

3. The method for preparing tempeh with hypoglycemic and anti-thrombotic effects according to claim 1 or 2, characterized in that: The freeze-thaw treatment is as follows: firstly, the dried whole soybeans are placed in a cold storage at -5°C to -20°C for 10 to 12 hours, then taken out and placed at room temperature for thawing for 3 to 5 hours, and then the refrigeration and thawing are continued, and the process is repeated 2 to 3 times.

4. The method for preparing tempeh with hypoglycemic and anti-thrombotic effects according to claim 1 or 2, characterized in that: The acidified water mist is obtained by adjusting the pH of water to 5 to 6 using acetic acid.

5. The method for preparing tempeh with hypoglycemic and anti-thrombotic effects according to claim 1 or 2, characterized in that: The pressure of the pressurization is 0.1 to 5 MPa; the pressure of the micro-pressure is 0.001 to 0.005 MPa; the pressure of the decompression is -0.05 to -0.02 MPa.

6. The method for preparing tempeh with hypoglycemic and anti-thrombotic effects according to claim 1 or 2, characterized in that: The mass concentration of the ethanol solution is 40-60%; the mass concentration of the acetic acid solution is 1-3%.

7. The method for preparing tempeh with hypoglycemic and anti-thrombotic effects according to claim 1, characterized in that: In step (3), the soaking time is 8-12 hours.

8. The method for preparing tempeh with hypoglycemic and anti-thrombotic effects according to claim 1, characterized in that: In step (5), the preparation method of the oligosporus Rhizopus fermentation agent is as follows: 20-30 parts of soybean powder, 1-3 parts of milk fat, 4-9 parts of glucose and 15-20 parts of water are mixed, and then sterilized at high temperature to obtain a fermentation base material; 1-5% of the weight of the fermentation base material of organic acid is added to the fermentation base material and mixed; then 0.1-0.5% of the weight of the fermentation base material of oligosporus Rhizopus is inoculated; the mixture is fermented at 20-28° C. for 1-2 days, and then dried at low temperature to obtain the oligosporus Rhizopus fermentation agent.

9. The method for preparing tempeh with hypoglycemic and anti-thrombotic effects according to claim 8, characterized in that: The organic acid is one of malic acid, acetic acid or citric acid.

10. The method for preparing tempeh with hypoglycemic and anti-thrombotic effects according to claim 8, characterized in that: The low temperature drying is drying at 4-8°C to a moisture content of 20-30%.

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