Soybean fermentation method, product and application

Abstract

The invention provides a soybean fermentation method, a product and application, and relates to the technical field of fermentation. According to the present invention, the soybean fermentation product with characteristics of high gamma-aminobutyric acid content and depression symptom improving effect is obtained by adding the sodium glutamate solution to the soybean for soaking and then carrying out the lactobacillus fermentation, and the preparation method can reduce the inoculation amount of the lactobacillus by 97.5-98.5%, and can shorten the fermentation period by 6 h.

Description

Technical Field

[0001] The present invention relates to the technical field of food fermentation, and in particular to a soybean fermentation method, product and application. Background Art

[0002] Soybeans contain basic nutrients such as fat, sugar, multiple vitamins, and minerals. They are a rich source of high-quality protein, polyunsaturated fatty acids, and a variety of functional biologically active substances. Soybeans do not contain cholesterol and lactose, which meets people's pursuit of green, environmental protection, and health in recent years. Soy milk is fermented to break down complex compounds into smaller molecules, which can improve the absorption rate of nutrients, increase the content of active substances such as γ-aminobutyric acid and soy isoflavones, and reduce the beany smell, improving the taste and flavor of soybean products.

[0003] GABA is a non-proteinaceous natural amino acid formed by glutamate decarboxylase-catalyzed decarboxylation. GABA is the main neurotransmitter in the central nervous system of mammals. GABA and its receptors are closely related to human emotions, psychology, and neurodegenerative diseases. A decrease in its level or function will lead to a decrease in the transmission function of inhibitory neurons, which in turn leads to the occurrence of depression, an emotional disease.

[0004] Therefore, proper supplementation of human γ-aminobutyric acid through soybean fermentation products is of great significance for maintaining the health of the nervous system and inhibiting depression. Summary of the invention

[0005] The present invention provides a soybean fermentation method, product and application. Sodium glutamate solution is added to soybeans for soaking, and then fermented with lactobacillus to obtain a soybean fermentation product with high γ-aminobutyric acid content and the effect of improving depression symptoms. At the same time, the inoculation amount of lactobacillus can be reduced by 97.5% to 98.5%, and the fermentation cycle can be shortened by 6 hours.

[0006] In one aspect, the present invention provides a soybean fermentation method, comprising the following steps: (1) Soaking soybeans: Add sodium glutamate solution to soybeans and soak them at room temperature; (2) Pulping: Mix the soaked soybeans with distilled water and white sugar, and boil and pulp them to obtain soy milk; (3) Inoculation and fermentation: the soy milk obtained in step (2) is cooled to room temperature, filtered, and sterilized at high temperature. After cooling to room temperature, lactobacillus is inoculated into the soy milk for anaerobic fermentation.

[0007] Furthermore, the concentration of the sodium glutamate solution in step (1) is 5-7 g / L, and the amount added is 8-12 times the mass of soybeans.

[0008] Furthermore, the soaking time in step (1) is 10 to 20 hours.

[0009] Furthermore, the solid-liquid ratio of soybeans to distilled water in step (2) is 1:12-1:16; and the amount of white sugar added is 3%-4% by mass of the soybeans.

[0010] Preferably, the solid-liquid ratio of soybeans to distilled water in step (2) is 1:14, and the amount of white sugar added is 4% by mass of the soybeans.

[0011] Furthermore, the temperature of the high temperature sterilization in step (3) is 90°C to 95°C.

[0012] Furthermore, the lactobacillus described in step (3) is Lactobacillus paracasei, Lactobacillus acidophilus, Lactobacillus helveticus, or Lactobacillus rhamnosus.

[0013] Furthermore, the Lactobacillus described in step (3) is Lactobacillus powder.

[0014] Furthermore, the live bacterial concentration of Lactobacillus in step (3) is 10 6 ~10 8 CFU / g, and the inoculation amount is 0.03%~0.07% of the volume of the soy milk, for example, it can be 0.03%~0.04%, 0.04%~0.05%, 0.05%~0.06%, 0.06%~0.07%.

[0015] Furthermore, the time of the anaerobic fermentation in step (3) is 2 h to 8 h, for example, 2 to 3 h, 2 to 4 h, 2 to 5 h, 2 to 6 h, 2 to 7 h, or 2 to 8 h.

[0016] In another aspect, the present invention provides a soybean fermentation product prepared by the following method: (1) Soaking soybeans: Add sodium glutamate solution to soybeans and soak them at room temperature; (2) Pulping: Mix the soaked soybeans with distilled water and white sugar, and boil and pulp them to obtain soy milk; (3) Inoculation and fermentation: the soy milk obtained in step (2) is cooled to room temperature, filtered, and sterilized at high temperature. After cooling to room temperature, lactobacillus is inoculated into the soy milk for anaerobic fermentation to obtain a soybean fermentation product.

[0017] Furthermore, the concentration of the sodium glutamate solution in step (1) is 5-7 g / L, and the amount added is 8-12 times the mass of soybeans.

[0018] Furthermore, the soaking time in step (1) is 10 to 20 hours.

[0019] Furthermore, the solid-liquid ratio of soybeans to distilled water in step (2) is 1:12-1:16; and the amount of white sugar added is 3%-4% by mass of the soybeans.

[0020] Preferably, the solid-liquid ratio of soybeans to distilled water in step (2) is 1:14, and the amount of white sugar added is 4% by mass of the soybeans.

[0021] Furthermore, the temperature of the high temperature sterilization in step (3) is 90°C to 95°C.

[0022] Furthermore, the lactobacillus described in step (3) is Lactobacillus paracasei, Lactobacillus acidophilus, Lactobacillus helveticus, or Lactobacillus rhamnosus.

[0023] Furthermore, the live bacterial concentration of Lactobacillus in step (3) is 10 6 ~10 8 CFU / g, and the inoculation amount is 0.03%-0.07% of the volume of the soy milk, for example, it can be 0.03%~0.04%, 0.04%~0.05%, 0.05%~0.06%, 0.06%~0.07%.

[0024] Furthermore, the time of the anaerobic fermentation in step (3) is 2 h to 8 h, for example, 2 to 3 h, 2 to 4 h, 2 to 5 h, 2 to 6 h, 2 to 7 h, or 2 to 8 h.

[0025] Furthermore, the soybean fermentation product obtained in step (3) can be a fermentation liquid, or can be further concentrated and dried to obtain a fermentation solid product.

[0026] In yet another aspect, the present invention provides a use of a soybean fermentation product in treating depression.

[0027] Furthermore, the application refers to the use of the above soybean fermentation product in improving weight loss, reduced exploratory ability, reduced desire to survive, lack of pleasure and depression symptoms.

[0028] Compared with the prior art, the technical solution of the present invention has the following advantages: (1) The present invention uses sodium glutamate to soak beans, which not only greatly reduces the beany smell of soybean fermentation products, but also effectively enriches the content of γ-aminobutyric acid. Compared with the lactobacillus soybean fermentation product without using sodium glutamate to soak beans, the content of γ-aminobutyric acid is increased by 54.87%. It also has a significant effect on improving reserpine-induced depression symptoms.

[0029] (2) The present invention uses sodium glutamate to soak beans and then ferment them. The inoculation amount of Lactobacillus is 0.03% to 0.07%, which is 97.5% to 98.5% less than the 2% inoculation amount disclosed in the prior art that does not use sodium glutamate soaking and directly performs Lactobacillus fermentation.

[0030] (3) The present invention uses sodium glutamate to soak beans and then ferment them. The γ-aminobutyric acid content reaches a relatively stable level of 1329 mg / L after 2 hours of fermentation. Then, until 10 hours of fermentation, the γ-aminobutyric acid content begins to decrease. Without soaking with sodium glutamate, directly using lactobacillus for fermentation, the γ-aminobutyric acid content can reach a basically stable level of 1015 mg / L until the 8th hour of fermentation, and the fermentation time can be shortened by 6 hours.

[0031] (4) During the soybean fermentation process of the present invention, the material-liquid ratio of soybean to distilled water is adjusted to 1:12-1:16, the amount of white sugar added is 3-4%, and the amount of lactobacillus inoculation is 0.03-0.07%. The beany smell of the soybean fermentation product can be significantly reduced, and the taste of the soybean fermentation product can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a line graph showing the effect of fermented soybean products on the body weight of mice; Figure 2 This is a bar graph showing the effect of soybean fermentation products on the total movement distance of mice in the open field test; Figure 3 This is a schematic diagram of the effect of soybean fermentation products on the open field test-movement trajectory of mice; Figure 4 This is a bar graph showing the effects of soybean fermentation products on the forced swimming test in mice; Figure 5 This is a bar graph showing the effects of soybean fermentation products on the sugar water preference experiment in mice.

[0033] In the above figures, CK represents the blank group, MD represents the model group, PC represents the positive drug group, HG represents the high-dose group, MG represents the medium-dose group, and LG represents the low-dose group. DETAILED DESCRIPTION

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0035] Example 1 (1) Soaking soybeans: Select soybeans with full grains, no insects or mildew, and remove impurities. Wash with distilled water and drain. Add 10 times the volume of soybean mass and 6g / L sodium glutamate solution to the washed soybeans and soak at room temperature for 15 hours. This will allow the soybeans to fully absorb water, which is more conducive to tissue crushing.

[0036] (2) Pulping: After washing the soaked soybeans, add 4% white sugar by volume in a soybean: distilled water mass ratio of 1:14 and mix, boil and homogenize in a pulper for 24 minutes. After cooling to room temperature, filter with an 80-mesh sieve to remove residue.

[0037] (3) Inoculation and fermentation: Sterilize the filtered soy milk at 95°C for 15 min. After the soy milk cools to room temperature, add the direct-injection fermentation strain Lactobacillus paracasei powder. The amount of Lactobacillus paracasei powder added is 0.07% of the volume of the soy milk to be fermented, and the concentration of live bacteria is 10 6 ~10 8 CFU / g. Fermentation was carried out at 37°C for 8 hours in a constant temperature and humidity anaerobic chamber.

[0038] Embodiments 2 to 17 Examples 2 to 5 respectively provide a method for preparing a soybean fermented product. The specific steps and parameters are basically the same as those of Example 1, except that the ratio of soybean to distilled water in step (2) is different.

[0039] Examples 6 to 9 respectively provide a method for preparing a soybean fermented product. The specific steps and parameters are basically the same as those in Example 1, except that the amount of white sugar added in step (2) is different.

[0040] Examples 10 to 13 respectively provide a method for preparing a soybean fermented product. The specific steps and parameters are basically the same as those in Example 1, except that the amount of probiotics added in step (3) is different.

[0041] Examples 14 to 17 respectively provide a method for preparing a soybean fermented product, wherein the specific steps and parameters are basically the same as those of Example 1, except that the fermentation time in step (3) is different.

[0042] Embodiments 18 to 20 Examples 18 to 20 provide a method for preparing a soybean fermented product, respectively. The specific steps and parameters are basically the same as those in Example 1, except that the fermentation strains in step (4) are different. The strains used are shown in Table 1.

[0043] Table 1 Fermentation strains in Examples 18 to 20

[0044] Comparative Example 1 A method for preparing a soybean fermented product, the preparation method is consistent with that in Example 1, except that sodium glutamate is not used for soaking soybeans, and the inoculation amount of Lactobacillus paracasei is 2%.

[0045] Comparative Example 2 A method for preparing a soybean fermented product, the preparation method is consistent with that of Example 1, except that Lactobacillus paracasei is not added for fermentation.

[0046] GABA determination and sensory evaluation 1. Evaluation Method (1) Determination method of γ-aminobutyric acid The concentrated stock solution of γ-aminobutyric acid was diluted in sequence to prepare 0, 0.2, 0.4, 0.6, 0.8, and 1.0 mg / mL γ-aminobutyric acid standard solutions. 1 mL of standard solution of different concentrations and treated fermentation supernatant were added to stoppered test tubes, 1.0 mL of 6% redistilled phenol and 1 mL of 0.01 mol / L borate buffer (pH 9.0) were added, mixed, and then 2.0 mL of 7.5% sodium hypochlorite solution was added, and the mixture was shaken thoroughly. After standing for 5 min, it was heated in boiling water for 10 min and ice bathed for 10 min. After the solution turned blue-green, 1.5 mL of 60% ethanol solution was added and the absorbance was measured at a wavelength of 645 nm. With the concentration of γ-aminobutyric acid as the horizontal axis and the absorbance as the vertical axis, a standard curve was drawn to calculate the content of γ-aminobutyric acid in the fermentation broth. The standard curve equation of γ-aminobutyric acid measured according to this method is y=1.2656x+0.1014, R²=0.9931.

[0047] (2) Sensory evaluation method Fourteen people (7 men and 7 women) were selected as a group to evaluate the sensory performance of soybean fermented products using flavor, color, taste and texture as indicators, and the average value was taken. The evaluation criteria are shown in Table 2.

[0048] Table 2 Sensory evaluation table of soybean fermentation products

[0049] 2. Evaluation results The soybean fermentation products obtained in Examples 1 to 5 were subjected to γ-aminobutyric acid content determination and sensory evaluation. The results are shown in Table 3. As the material-liquid ratio of soybeans to distilled water increases, the γ-aminobutyric acid content first increases, reaches a maximum value when the material-liquid ratio is 1:14, and then slowly decreases. The material-liquid ratio will affect the viscosity and concentration of the fermentation substrate. When the material-liquid ratio is small, the viscosity is large, and it is difficult for probiotics to use the substrate for fermentation, thereby making it difficult to synthesize γ-aminobutyric acid. And when the material-liquid ratio is 1:10, the soybean fermentation product has a heavy and uneven granular feel and a slight beany smell. When the material-liquid ratio is too large, the substrate concentration is low, and the ability to synthesize γ-aminobutyric acid decreases. When the material-liquid ratio is 1:12, 1:14 and 1:16, the texture is uniform and the taste is good, with almost no beany smell.

[0050] Table 3 GABA content and sensory scores of soybean fermentation products of Examples 1 to 5

[0051] The soybean fermentation products obtained in Example 1 and Examples 6 to 9 were subjected to γ-aminobutyric acid content determination and sensory evaluation. The results are shown in Table 4. Probiotics can use white sugar as a carbon source to carry out metabolic activities. At the same time, white sugar can adjust the taste of soybean fermentation products and be better accepted by consumers. The γ-aminobutyric acid content reaches the highest when the amount of white sugar added is 4%. When the amount of white sugar added is 3% and 4%, the sensory evaluation is the best with moderate sweetness, fermented milk flavor, and no beany smell.

[0052] Table 4 GABA content and sensory scores of soybean fermentation products of Examples 1 and 6 to 9

[0053] The soybean fermented products obtained in Example 1 and Examples 10 to 13 were subjected to γ-aminobutyric acid content determination and sensory evaluation. The results are shown in Table 5. The inoculation amount in the range of 0.01-0.09% has a significant difference in the fermentation production of γ-aminobutyric acid. With the increase of the inoculation amount, the γ-aminobutyric acid content continued to rise. When the inoculation amount was 0.07%, the content reached the highest. Then, when the inoculation amount increased to 0.09%, the γ-aminobutyric acid content decreased. This may be because the excessive inoculation amount caused the strain to show premature aging of the bacteria due to competition for substrates. At the same time, when the inoculation amount of the strain was 0.09%, the viscosity of the soybean fermented product was too viscous compared to others, and there was a slight beany smell.

[0054] Table 5 GABA content and sensory scores of soybean fermentation products of Examples 1 and 10 to 13

[0055] The soybean fermented products obtained in Example 1 and Example 14 to 17 were subjected to γ-aminobutyric acid content determination and sensory evaluation. The results are shown in Table 6. The fermentation time has a certain effect on improving the fermented product. In the early stage of fermentation, the probiotics are in the early stage of reproduction, and the probiotic production efficiency is low. When the fermentation time is extended, the fermentation efficiency gradually decreases with the further reproduction of the probiotics, but the fermentation flavor and some active substances are gradually enriched with the extension of the fermentation time. When the fermentation time is 2 hours, the γ-aminobutyric acid content has reached 1329mg / L, and then with the extension of the fermentation time, the γ-aminobutyric acid content slowly increases. Subsequently, when the fermentation is fermented to 10h, the γ-aminobutyric acid content decreases, which may be to resist the adverse environment. The synthesized γ-aminobutyric acid is converted into succinic semialdehyde by γ-aminobutyric acid transaminase, and succinic semialdehyde is converted into succinic acid by succinic semialdehyde dehydrogenase, and then enters the tricarboxylic acid cycle.

[0056] Table 6 GABA content of soybean fermentation products of Examples 1 and 14 to 17

[0057] The soybean fermented products obtained in Example 1 and Comparative Examples 1 to 2 were subjected to γ-aminobutyric acid content determination and sensory evaluation. The results are shown in Table 7. Compared with Comparative Example 1, the γ-aminobutyric acid content of the embodiment is higher, indicating that the use of sodium glutamate to soak soybeans can increase the γ-aminobutyric acid content in the fermented soybean products. Usually, when plants are stimulated by external factors, the body starts a self-defense mechanism, and the level of γ-aminobutyric acid in the body increases, which is beneficial for plants to adapt to changes in the external environment. Therefore, the level of γ-aminobutyric acid in plant raw materials can be increased by coercion. Glutamate decarboxylase catalyzes L-glutamate to generate γ-aminobutyric acid in the plant body, and the generated γ-aminobutyric acid is catalyzed by γ-aminobutyric acid transaminase and succinic semialdehyde dehydrogenase to generate succinic semialdehyde and succinic acid that enter the TCA cycle. These reactions and the glutamate decarboxylase catalytic reaction together constitute the γ-aminobutyric acid branch. When the soaked soybeans absorb and utilize sodium glutamate, the L-glutamate content in the tissue cells rises, the γ-aminobutyric acid synthesis ability is enhanced, and the content increases. Compared with Example 1, Example 1 has a lower beany smell, and the beany smell is better covered by soaking with sodium glutamate. Compared with Example 2, Example 1 has a more delicate, uniform and shiny texture, and is richer in fermented milk flavor.

[0058] Compared with Comparative Example 2, Example 1 has a higher content of γ-aminobutyric acid, indicating that the use of probiotic fermentation also increases the content of γ-aminobutyric acid in fermented soybean products to a certain extent. Microbial fermentation uses substances rich in glutamic acid as raw materials, and glutamate decarboxylase in microorganisms catalyzes the decarboxylation of L-glutamic acid to form γ-aminobutyric acid. Using microbial fermentation to increase the content of γ-aminobutyric acid in soybean fermentation products is safer and more environmentally friendly than chemical production of γ-aminobutyric acid. Compared with plant and animal production, it is easier to control production conditions using microorganisms. In terms of sensory evaluation, Example 1 uses probiotic fermentation compared to Comparative Example 2 which does not use probiotic fermentation. Example 1 is more delicate, uniform and shiny, and is also richer in fermented frankincense.

[0059] Table 7 GABA content of soybean fermentation products of Example 1 and Comparative Examples 1-2

[0060] Depression Symptoms Effect Test The efficacy of the soybean fermented product obtained in Example 1 was tested as follows: 1. Animal grouping and modeling After 7 days of adaptive feeding, the mice were randomly divided into 6 groups and numbered, namely, blank group (CK), model group (MD), positive drug group (PC), high-dose group (HG), medium-dose group (MG), and low-dose group (LG). Except for the blank control group, the mice in each group were given dietary intervention according to the above doses for 21 days. On the 21st day, mice in other groups except the blank group were injected with 1 mg / kg of reserpine for 3 days, and the blank group was injected with an equal dose of 0.9% NaCl every day. The dietary intervention dose was converted according to the GABA content of the probiotic soybean fermentation product, and different doses of soybean fermentation product powder replaced part of the normal feed for the mice to perform dietary intervention. The soybean fermentation product was first freeze-dried into powder, and then mixed with normal feed according to the intervention ratio. A small amount was put into the syringe and pressed into a rod to make enough for the mice to eat for three days at a time, and then put into the refrigerator. During the dietary intervention, the weight and food intake of the mice were recorded every day.

[0061] Table 8 Experimental groups and treatments

[0062] The results are as follows Figure 1 As shown, the weight of mice in each group showed an upward trend in the first four weeks. After the first week of adaptation, the blank group and the positive control group gained weight faster than other drug groups. This may be because the replacement of feed for mice in the drug group requires new exploration and adaptation for mice. Starting from the fifth week, after three consecutive days of injection of reserpine injection, the weight of other groups except the blank group showed a significant decrease. Among them, the weight loss in the model group was the most obvious, with a decrease rate of 18.13%. There was a significant difference between the weight loss in the model group and the blank group (p < 0.05), indicating that the model was successful. The weight loss in the drug group was significantly lower than that in the model group, indicating that the soybean fermentation product prepared by the present invention can significantly improve the weight loss of depressed mice caused by reserpine.

[0063] 2. Open field experiment The experimental animals were placed in the OFT-100 rat open-field activity test apparatus (625 mm×740 mm×510 mm), and the movement time and distance of the mice were recorded within 5 minutes. The experiment was conducted in a quiet, light-proof environment. After each mouse was tested, the animal excrement inside the open-field box was cleaned in time, and 75% alcohol solution was sprayed to remove odor, so as to prevent the feces, urine, odor and other information left by the previous animal from affecting the next test results.

[0064] like Figure 2 As shown in the figure, the total distance of movement in the blank group was significantly higher than that in the other groups, and there was a significant difference compared with the model group (p < 0.05). After intervention with soybean fermented products rich in γ-aminobutyric acid, the total distance of movement in the high-dose group was higher than that in the medium- and low-dose groups. Figure 3As shown in the figure, the blank group crossed the central area more times and the trajectory was uniform throughout the test box. The movement trajectory of the mice in the model group was simple and showed obvious symptoms of depression, indicating that the model was successfully established. The mice in the high-dose group crossed the center more times than the mice in the medium and low-dose groups.

[0065] In summary, the soybean fermentation product prepared by the present invention can effectively inhibit the depression symptoms of model mice. At the same time, the higher the content of γ-aminobutyric acid, the more obvious it is.

[0066] 3. Forced swimming test Place the mice in a cylindrical transparent glass tank with a water temperature of 20-25℃, a height of 20 cm, and a diameter of 10 cm. After acclimation for 2 minutes, record the cumulative immobility time of the mice within 4 minutes. After the end, wipe them with a towel and blow dry their hair with a hair dryer. The mice were defined as immobile when they floated on the water or had only slight movements necessary to maintain breathing and floating.

[0067] The results are as follows Figure 4 As shown in the figure, the immobility time of mice in different groups was different. The average immobility time of mice in the blank group was 47.5s, and the average immobility time of mice in the model group was 206.4s. The model group was significantly higher than the blank group, which indicated that the mice in the model group had a low desire to survive and showed obvious symptoms of depression, indicating that the model was successfully constructed. The immobility time of mice in the positive drug group was 138.3s, which was 68.1s lower than that in the model group, indicating that fluoxetine can improve the depressive symptoms of mice. The immobility time of mice in the high-dose group was significantly higher than that in the medium and low-dose groups, indicating that the higher the content of γ-aminobutyric acid, the more it can improve the desire to survive of mice.

[0068] In summary, the soybean fermentation product prepared by the present invention can effectively improve the survival desire of model mice. At the same time, the higher the content of γ-aminobutyric acid, the more obvious it is.

[0069] 4. Sugar water preference experiment Before the formal test, two bottles of 1% sucrose water were provided to the mice. After drinking for 24 hours, one of the bottles of sucrose water was replaced with pure water, and the mice continued to drink for 24 hours. Subsequently, the mice were fasted and deprived of water for 24 hours before the sugar water preference test. At the same time, two bottles of water were given to each cage of mice in advance: 200 mL of 1% sucrose water and 200 mL of pure water. They were weighed before placement, and the water outlet was ensured to be leak-proof. The positions were swapped at regular intervals during the test. After 12 hours of free water intake, the two bottles were removed and weighed.

[0070] The sugar water preference test is one of the effective indicators for evaluating anhedonia, which is an important manifestation of depression. Figure 5It can be seen that the sugar preference rate in the model group was 33.13% lower than that in the blank group, and there was a significant difference (p < 0.05). This indicates that the model group obviously had anhedonia and the model was successfully established. The sugar preference rate in the positive drug group was 82.68%; the sugar preference rate in the high-dose group was 76.32%; the sugar preference rate in the medium-dose group was 68.96%; and the sugar preference rate in the low-dose group was 62.23%. The sugar preference rate in the high-dose group was close to that in the positive drug group, indicating that the more γ-aminobutyric acid is contained, the closer the effect of soybean fermentation products in relieving anhedonia in mice is to the therapeutic effect of fluoxetine drugs.

[0071] In summary, the soybean fermentation product prepared by the present invention can effectively improve the anhedonia of model mice. At the same time, the higher the content of γ-aminobutyric acid, the more obvious the effect.

[0072] Intervention of the soybean fermentation product prepared by the present invention on reserpine-depressed mice can improve the depressive symptoms of the mice in terms of body weight, exploration ability, desire for survival, and lack of pleasure.

Claims

1. A soybean fermentation method, characterized in that: The following steps are involved: (1) Soaking soybeans: Add sodium glutamate solution to soybeans and soak them at room temperature; (2) Pulping: Mix the soaked soybeans with distilled water and white sugar, and boil and pulp them to obtain soy milk; (3) Inoculation and fermentation: the soy milk obtained in step (2) is cooled to room temperature, filtered, and sterilized at high temperature. After cooling to room temperature, lactobacillus is inoculated into the soy milk for anaerobic fermentation.

2. The method according to claim 1, characterized in that The concentration of the sodium glutamate solution in step (1) is 5-7 g / L, and the amount added is 8-12 times the mass of soybeans.

3. The method according to claim 1, characterized in that The material-liquid ratio of the soaked soybeans to distilled water in step (2) is 1:12-1:16; the amount of the added white sugar is 3%-4% by mass of the soybeans.

4. The method according to claim 1, characterized in that The solid-liquid ratio of the soaked soybeans to distilled water in step (2) is 1:14; the amount of white sugar added is 4% by mass of the soybeans.

5. The method according to claim 1, characterized in that The lactobacillus described in step (3) is Lactobacillus paracasei, Lactobacillus acidophilus, Lactobacillus helveticus, or Lactobacillus rhamnosus.

6. The method according to claim 1, characterized in that The lactobacillus in step (3) is lactobacillus powder.

7. The method according to claim 6, characterized in that The live bacteria concentration of the lactobacillus powder is 10 6 ~10 8 CFU / g, and the inoculation amount is 0.03%~0.07% of the volume of soy milk.

8. The method according to claim 1, characterized in that The anaerobic fermentation time in step (3) is 2h~8h.

9. The method according to claim 1, characterized in that: Also includes the steps: (4) After inoculating Lactobacillus into soybean milk for anaerobic fermentation as described in step (3), freeze-drying is continued to obtain soybean fermentation powder.

10. A soybean fermentation product, characterized in that: It is prepared by the method according to any one of claims 1 to 9.

11. Use of the soybean fermentation product prepared by the method according to any one of claims 1 to 9 in the preparation of a drug for treating depression.

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