Fermentation agent for bean dregs, fermented bean product and preparation method thereof

Abstract

The present invention discloses a fermentation agent for bean dregs, a fermented bean product, and a preparation method thereof, and relates to the field of fermentation engineering technology. Lactic acid bacteria and Neurospora are used as fermentation agents in the fermentation of bean dregs. Compared with traditional processes, the fermentation time can be greatly shortened, which is conducive to promoting the industrial application of the fermentation process and achieving the purpose of expanded production. The present invention can make the texture of the fermented product more firm through a short fermentation time, and the product is rich in nutrition and excellent in flavor. By industrializing each link, a fermentation method that can be applied industrially is provided.

Description

Technical Field

[0001] The present invention relates to the technical field of fermentation engineering, and in particular to a fermentation agent for bean dregs, a fermented bean product and a preparation method thereof. Background Art

[0002] Okara is a by-product left after filtration during the production of soy products such as soy milk and tofu. Fresh dregs have a high water content (about 70% to 80%), which makes them extremely perishable and unfavorable for transportation and further food processing. Therefore, dregs are often directly discarded as processing waste or simply processed into crude feed, causing certain environmental problems and economic losses.

[0003] "Red Mushroom Tofu", an intangible cultural heritage of Renju Town, Meizhou City, Guangdong Province, is a traditional fermented soy product that uses bean dregs, a major by-product, as raw material and is fermented by microorganisms. It has a history of consumption in the local area for thousands of years. However, the traditional "red mushroom tofu" fermentation process is not standardized and cannot be precisely controlled. Therefore, the fermented final product has many problems such as a large number of foreign bacteria, odor and lack of flavor, and is restricted by geographical location and has low daily output.

[0004] More importantly, the traditional fermentation process has a long fermentation cycle and limited raw material processing capacity, which is far from meeting the needs of batch processing of bean dregs.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The present invention aims to provide a fermentation agent for bean dregs, a fermented bean product and a preparation method thereof, aiming to prepare a product with a firm texture and rich nutrition through a short fermentation time.

[0007] The present invention is achieved in that:

[0008] In a first aspect, the present invention provides a fermentation agent for bean dregs, comprising lactic acid bacteria and Neurospora, wherein the concentration ratio of the lactic acid bacteria to the Neurospora is 1-3:1.

[0009] In an optional embodiment, the concentration ratio of lactic acid bacteria to Neurospora is 2-3:1; preferably 3:1.

[0010] In an optional embodiment, the fermentation agent for bean dregs is in the form of bacterial cake or bacterial powder;

[0011] Preferably, a culture medium is further included, and lactic acid bacteria and Neurospora are inoculated on the culture medium, with a mass ratio of the total inoculation amount to the culture medium being 0.2-0.4:100.

[0012] In an optional embodiment, the culture medium comprises, by weight: peanut hull, potato flour, corn cob flour and bean dregs;

[0013] Preferably, the mass ratio of peanut hull, potato flour, corn cob flour and bean dregs is 1:1-3:0.5-1.5:1-3.

[0014] In a second aspect, the present invention provides a method for preparing a fermented soy product, comprising: inoculating a soy dregs starter according to any one of the aforementioned embodiments into a soy dregs matrix for fermentation.

[0015] In an optional embodiment, the okara starter is added in the form of fermented bacteria cake, and the mass ratio of the okara substrate to the fermented bacteria cake is 100:4-6;

[0016] Preferably, the preparation process of the fermentation cake includes: stirring and mixing lactic acid bacteria and Neurospora with the culture medium, and then freeze-drying, controlling the stirring speed to 10-30 r / min, the stirring time to 10-20 min, the freeze-drying temperature to -50 to -30°C, and the freeze-drying time to 8-12 h.

[0017] In an optional embodiment, after the okara substrate is inoculated with the okara starter, it is first subjected to a shaping process and then fermented;

[0018] Among them, the inoculation of bean dregs with fermentation agent is to use an octagonal roller to cool the fried bean dregs, add bacterial cake or bacterial powder, and rotate the materials to mix evenly, controlling the speed to 40-50r / min;

[0019] Among them, the forming process is to perform compaction forming;

[0020] Preferably, the compacting and molding process comprises: placing the inoculated okara in a regular container and compacting and molding it using a hydraulic press.

[0021] In an optional embodiment, the fermentation temperature is 25-35°C, the humidity is 60-70%, and the fermentation time is 20-30h;

[0022] Preferably, the fermentation time is 22-26 hours;

[0023] Preferably, the fermentation process is carried out in a place with good air circulation and light;

[0024] Preferably, the fermentation is completed and then frozen.

[0025] In an optional embodiment, the preparation process of the okara substrate includes sequentially crushing, dehydrating, sterilizing and frying fresh okara;

[0026] Preferably, the crushing is carried out using a colloid mill, and the particle size after crushing is controlled to be 0.2-0.3 mm;

[0027] Preferably, the dehydration is performed by placing the material in a centrifuge, and controlling the moisture content of the dehydrated bean dregs to be 70-80%; more preferably, the speed of the centrifuge is controlled to be 800-1200 r / min;

[0028] Preferably, the sterilization is carried out at a temperature of 115-125° C. for 20-40 minutes; more preferably, the sterilization is carried out using a steamer;

[0029] Preferably, the frying is carried out in a planetary frying pan, the moisture content after frying is controlled to be 60-70%, the frying temperature is 70-80° C., and the frying time is 25-35 minutes.

[0030] In a third aspect, the present invention provides a fermented soy product prepared by the preparation method of the aforementioned embodiment.

[0031] The present invention has the following beneficial effects: Utilizing lactic acid bacteria and Neurospora as fermentation agents for fermenting bean dregs significantly shortens the fermentation time compared to traditional processes, facilitating the industrial application of the fermentation process and achieving the goal of expanding production. Furthermore, the present invention can achieve a firmer texture in the fermented product through a shorter fermentation time, while also enriching the product with rich nutrition and excellent flavor. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 A flow chart comparing the traditional fermentation of red fungus tofu and the industrialized production process of the present invention;

[0034] Figure 2 This is a picture of the product before fermentation;

[0035] Figure 3 This is the first finished product after industrial fermentation;

[0036] Figure 4 This is the second finished product after industrial fermentation;

[0037] Figure 5 This is the third finished product after industrial fermentation. DETAILED DESCRIPTION

[0038] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0039] Please refer to Figure 1 The embodiment of the present invention is based on the traditional process of making red mushroom tofu. The traditional process is to fry fresh bean dregs, spread them out to dry, inoculate them, manually extrude them into shapes, and then naturally ferment them. This application improves the process system and introduces modern mechanical equipment to replace manual operations. It uses precise environmental detection instruments to control the fermentation environment in real time, and uses monitoring data instead of experience to guide production. It can solve the problem of bean dregs surplus in batches, produce green fermented products with stable quality, and effectively promote the high-value utilization of bean dregs.

[0040] An embodiment of the present invention provides a method for preparing a fermented soy product, comprising the following steps:

[0041] S1. Preparation of okara matrix

[0042] The preparation process of the bean dregs matrix includes crushing, dehydrating, sterilizing and frying the fresh bean dregs in sequence to obtain moisture content that meets the requirements.

[0043] Specifically, fresh bean dregs refer to the by-products remaining after filtration during the production of soy products such as soy milk and tofu, which have a high water content.

[0044] In some embodiments, the pulverization is carried out in sequence using a colloid mill to control the particle size after pulverization to be 0.2-0.3 mm, such as 0.20 mm, 0.25 mm, and 0.30 mm.

[0045] In some embodiments, dehydration is performed by placing the material in a centrifuge, and controlling the moisture content of the dehydrated okara to be 70-80%. For example, the moisture content after dehydration can be controlled to be 70%, 75%, 80%, etc. Preferably, the speed of the centrifuge is controlled to be 800-1200 rpm. By precisely controlling the operating parameters of the centrifuge, the moisture content of the processed okara meets the requirements.

[0046] In some embodiments, sterilization is performed at a temperature of 115-125° C. for 20-40 minutes. This can be performed using a steamer, with the operating parameters of the steamer precisely controlled to ensure the sterilization effect. Specifically, the steamer sterilization temperature can be 115° C., 120° C., 125° C., etc., and the sterilization time can be 20 minutes, 30 minutes, 40 minutes, etc.

[0047] In some embodiments, the stir-frying is performed using a planetary stir-fry pan, and the moisture content after stir-frying is controlled to be 60-70% (e.g., 60%, 65%, 70%, etc.), the stir-frying temperature is controlled to be 70-80° C. (e.g., 70° C., 75° C., 80° C., etc.), and the stir-frying time is controlled to be 25-35 minutes (e.g., 25 minutes, 30 minutes, 35 minutes, etc.). By precisely controlling the stir-frying temperature and time, the moisture content after stir-frying is ensured to meet the requirements.

[0048] S2. Vaccination

[0049] The okara substrate is inoculated with a fermentation agent for okara, which includes lactic acid bacteria and Neurospora, with a concentration ratio of 1-3:1. The inventors creatively employed a composite inoculum of lactic acid bacteria and Neurospora as the okara fermentation agent. By optimizing their dosage ratio, the fermentation time can be significantly shortened, creating conditions for industrial application.

[0050] Specifically, the Neurospora used in the embodiment of the present invention is Neurospora intermedia, which is an existing strain.

[0051] In some embodiments, the fermentation agent for inoculating bean dregs is prepared by cooling the roasted bean dregs using an octagonal roller, adding bacterial cake or bacterial powder, and rotating the materials to mix them evenly, with the rotation speed controlled at 40-50 r / min.

[0052] Specifically, the lactic acid bacteria are commercially available strains, which may be Lactobacillus plantarum HH-LP56 (Xi'an Jushengyuan Biotechnology Co., Ltd.).

[0053] In some embodiments, the concentration ratio of Lactobacillus to Neurospora can be 1:1, 2:1, 3:1, or any value between these values. Preferably, the concentration ratio of Lactobacillus to Neurospora is 2-3:1, more preferably 3:1. This ratio minimizes fermentation time; a ratio that is too high or too low will result in prolonged fermentation time.

[0054] In some embodiments, the fermentation agent for bean dregs is in the form of bacterial cake; a culture medium is also included, and lactic acid bacteria and Neurospora are inoculated on the culture medium, and the mass ratio of the total inoculum amount to the culture medium is 0.2-0.4:100, such as 0.2:100, 0.3:100, 0.4:100, etc.

[0055] In some embodiments, the preparation process of the fermented cake includes: stirring and mixing lactic acid bacteria and Neurospora with the culture medium, and then freeze-drying, controlling the stirring speed to 10-30r / min, the stirring time to 10-20min, the freeze-drying temperature to -50 to -30°C, the time to 8-12h, and breaking up with a blender and then cooling and inoculating to form a cake.

[0056] In some embodiments, the culture medium comprises, by weight, peanut husk, potato flour, corn cob flour, and bean dregs; the mass ratio of peanut husk, potato flour, corn cob flour, and bean dregs is 1:1-3:0.5-1.5:1-3. The culture medium can adopt the above composition, but is not limited thereto.

[0057] Furthermore, the mass ratio of the dregs substrate to the fermented cake is 100:4-6, such as 100:4, 100:5, 100:6, etc. It is advisable to control the amount of the fermented cake within the above range to further improve the nutritional value of the fermented product.

[0058] S3, molding process

[0059] After the bean dregs substrate is inoculated with a fermentation agent for bean dregs, a shaping process is first performed and then fermentation is performed. The shaping process is compaction shaping so that the shape of the product after fermentation meets the requirements.

[0060] In some embodiments, the compacting and forming process includes: placing the inoculated okara in a regular container and compacting and forming it using a hydraulic press. The compacting is performed by hydraulic forming to ensure a good forming effect.

[0061] S4. Fermentation

[0062] The formed material is placed in a fermentation vessel for fermentation at a temperature of 25-35°C, a humidity of 60-70%, and a fermentation time of 20-30 hours. The fermentation process is carried out in a place with air circulation and light, through constant temperature, constant humidity, and light-controlled fermentation, and the fermentation conditions are precisely controlled to ensure a uniform product.

[0063] Specifically, the fermentation temperature can be 25°C, 30°C, 35°C, etc., the humidity can be 60%, 65%, 70%, etc., and the fermentation time can be 20 hours, 25 hours, 30 hours, etc. Preferably, the fermentation time is 22-26 hours. Through a short fermentation time, a firm texture, rich nutrition, good flavor can be prepared, and the free amino acid and soluble dietary fiber contents are maintained at high levels.

[0064] In some embodiments, the product is frozen after fermentation is completed to maintain the product properties during storage.

[0065] The embodiment of the present invention provides a fermented soy product prepared by the above preparation method, which has the advantages of firm texture and rich nutrition, especially high content of free amino acids and soluble dietary fiber.

[0066] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0067] Example 1

[0068] This embodiment provides a method for preparing a fermented soy product, comprising the following steps:

[0069] (1) Preparation of okara matrix

[0070] Fresh bean dregs (with a water content of 82.39%) were taken and crushed, dehydrated, sterilized and fried in sequence.

[0071] The pulverization is carried out in a grinder, and the particle size after pulverization is about 0.25 mm.

[0072] Dehydration is to place the material in a centrifuge and control the speed of the centrifuge to be 1000r / min. The moisture content of the dehydrated bean dregs is about 75%.

[0073] Sterilization is carried out using a steamer at 120°C for 30 minutes.

[0074] The frying is carried out in a planetary frying pan, the frying temperature is controlled to be 75° C., the frying time is 30 minutes, and the moisture content after frying is about 65%.

[0075] (2) Vaccination

[0076] Preparation of a starter culture for okara: Lactic acid bacteria and Neurospora are mixed with a culture medium and then freeze-dried. The stirring speed is controlled at 20 r / min for 15 minutes and the freeze-drying temperature is -40°C for 10 hours. The mixture is then blended in a blender, cooled, and inoculated to form a cake. The concentration ratio of lactic acid bacteria to Neurospora is 1:1, and the mass ratio of the total inoculum to the culture medium is 0.3:100. The culture medium composition, by mass, includes peanut husk, potato flour, corncob flour, and okara; the mass ratio of peanut husk, potato flour, corncob flour, and okara is 1:2:1:2.

[0077] Inoculation: Inoculate the okara substrate with the fermentation culture, with a mass ratio of okara substrate to fermentation cake of 100:5. Cool the roasted okara in an octagonal drum, then add the fermentation cake. Rotate the drum to mix thoroughly, controlling the speed at 45 rpm.

[0078] (3) Molding process

[0079] The inoculated dregs are placed in a regular container and compacted using a hydraulic press, such as Figure 2 shown.

[0080] (4) Fermentation

[0081] The formed material is placed in a fermentation vessel for fermentation at a temperature of 30°C, a humidity of 65%, and a fermentation time of 25 hours. The fermentation process is carried out in a place with air circulation and light.

[0082] Fermented products such as Figure 3-Figure 5 shown.

[0083] Example 2

[0084] The only difference from Example 1 is that the concentration ratio of lactic acid bacteria to Neurospora is 2:1.

[0085] Example 3

[0086] The only difference from Example 1 is that the concentration ratio of lactic acid bacteria to Neurospora is 3:1.

[0087] Example 4

[0088] The only difference from Example 1 is that the concentration ratio of lactic acid bacteria to Neurospora is 4:1.

[0089] Example 5

[0090] The only difference from Example 1 is that in step (2), the mass ratio of the total inoculum amount to the culture medium is 0.2:100.

[0091] Example 6

[0092] The only difference from Example 1 is that in step (2), the mass ratio of the total inoculum amount to the culture medium is 0.4:100.

[0093] Example 7

[0094] The only difference from Example 1 is that in step (2), the mass ratio of the dregs substrate to the fermented bacteria cake is 100:4.

[0095] Example 8

[0096] The only difference from Example 1 is that in step (2), the mass ratio of the dregs substrate to the fermented bacteria cake is 100:6.

[0097] Comparative Example 1

[0098] The only difference from Example 1 is that Neurospora is replaced by an equal amount of Monascus.

[0099] Comparative Example 2

[0100] The only difference from Example 1 is that Neurospora is replaced by an equal amount of Bacillus subtilis.

[0101] Comparative Example 3

[0102] Use traditional fermentation process, the specific steps are shown in Figure 1 .

[0103] The fresh bean dregs are fried, spread out to dry, inoculated, manually squeezed into shape, and naturally fermented.

[0104] Comparative Example 4

[0105] The only difference from Example 1 is that Neurospora is replaced by an equal amount of lactic acid bacteria.

[0106] Comparative Example 5

[0107] The only difference from Example 1 is that the fermentation temperature is 35°C.

[0108] Test Example 1

[0109] The fermentation time and soluble dietary fiber content of the methods in the test examples and comparative examples are shown in Table 1.

[0110] Maturity time test standard: The maturity standard is that the product is light yellow in color and has a mushroom aroma.

[0111] Table 1 Fermentation time and soluble dietary fiber content test results

[0112]

[0113] As can be seen from Table 1, the soy dregs starter provided by the present invention significantly shortens fermentation time. Furthermore, a 3:1 ratio of lactic acid bacteria to Neurospora is optimal, minimizing fermentation time. Furthermore, this ratio also maximizes soluble dietary fiber content.

[0114] Test Example 2

[0115] The products prepared in the examples and comparative examples were characterized by GC-MS. The test results are shown in Table 2.

[0116] Table 2 GC-MS test results

[0117]

[0118] It can be seen that the product prepared in Example 3 contains significantly more types of compounds and a higher ester content, which is a guarantee of its better flavor.

[0119] Test Example 3

[0120] (1) The daily processing amount of bean curd residue and the yield of red fungus tofu in Example 3 and Comparative Example 3 were tested. The results are shown in Table 3.

[0121] Table 3 Daily yields of bean dregs and red fungus tofu processed by traditional fermentation and industrial production

[0122] Production method Daily processed bean dregs (kg) Red mushroom tofu production (kg) Traditional fermentation 100 70 Industrial production 500 450

[0123] It can be seen that the process method of the embodiment of the present application can process significantly more bean dregs per day, reaching 5 times that of traditional fermentation, and the output of red fungus tofu can reach more than 6 times that of the traditional process.

[0124] (2) The nutritional content of the red mushroom tofu prepared in Example 3 and Comparative Example 3 was tested. The results are shown in Table 4.

[0125] Table 4 Nutritional content of traditional fermented and industrially produced red fungus tofu

[0126] Nutrition (g / 100g) Fresh bean dregs Traditional fermentation Industrial production Moisture <![CDATA[82.39±0.59 a ]]> 77.51±0.6 <![CDATA[76.79±0.64 b ]]> Fat <![CDATA[24.97±0.91 a ]]> 19.35±0.4 <![CDATA[17.28±0.67 b ]]> protein <![CDATA[22.08±0.1 a ]]> 21.86±0.3 <![CDATA[17.93±0.05 b ]]> ash content <![CDATA[3.68±0.20 a ]]> <![CDATA[1.51±0.57 b ]]> <![CDATA[1.61±0.35 b ]]> Soluble dietary fiber <![CDATA[5.74±0.15 c ]]> <![CDATA[7.57±0.74 b ]]> <![CDATA[9.25±0.22 a ]]> Insoluble dietary fiber <![CDATA[65.91±0.08 a ]]> 58.00±0.2 <![CDATA[47.04±0.63 c ]]> Total dietary fiber <![CDATA[71.65±0.07 a ]]> 66.57±0.0 <![CDATA[56.29±0.84 c ]]>

[0127] It can be seen that the red mushroom tofu prepared in the embodiment of the present invention is rich in nutrition and has a significantly higher content of soluble dietary fiber.

[0128] (3) The flavor amino acid content of the red mushroom tofu prepared in Example 3 and Comparative Example 3 was tested. The results are shown in Table 5.

[0129] Table 5 Differences in the flavor amino acid content of traditional fermented and industrially produced red fungus tofu

[0130]

[0131]

[0132] Note: Superscripts represent significance, and different letters represent significant differences.

[0133] (4) The flavor substance content of the red mushroom tofu prepared in Example 3 and Comparative Example 3 was tested. The results are shown in Table 6.

[0134] Table 6 Differences in the content of flavor substances in red fungus tofu produced by traditional process and industrial production

[0135]

[0136]

[0137] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing a fermented soy product, characterized in that: include: Inoculating a bean dregs starter into a bean dregs substrate for fermentation, wherein the bean dregs starter comprises lactic acid bacteria and Neurospora, wherein the concentration ratio of the lactic acid bacteria to the Neurospora is 3:1, the lactic acid bacteria is Lactobacillus plantarum HH-LP56, and the Neurospora is Neurospora intermedia; The okara starter is added in the form of a fermentation cake, and the mass ratio of the okara substrate to the fermentation cake is 100:4-6. The preparation process of the fermentation cake includes: stirring and mixing the lactic acid bacteria and the Neurospora with a culture medium, and then freeze-drying; The mass ratio of the total inoculum amount of the lactic acid bacteria and the Neurospora to the culture medium is 0.2-0.4:

100.

2. The preparation method according to claim 1, characterized in that The culture medium comprises peanut husk, potato flour, corn cob flour and bean dregs.

3. The preparation method according to claim 2, characterized in that The mass ratio of peanut hull, potato flour, corn cob flour and bean dregs is 1:1-3:0.5-1.5:1-3.

4. The preparation method according to claim 1, characterized in that During the preparation of the fermented cake, the stirring speed is controlled to be 10-30 r / min, the stirring time is 10-20 min, the freeze-drying temperature is -50~-30°C, and the freeze-drying time is 8-12 h.

5. The preparation method according to claim 1, characterized in that After inoculating the bean dregs fermentation agent into the bean dregs substrate, the bean dregs substrate is first subjected to a shaping process and then fermented; Among them, the inoculation of the bean dregs with the fermentation agent is to use an octagonal roller to cool the fried bean dregs, add the bacterial cake or bacterial powder, and rotate the materials to mix evenly, and control the speed to 40-50r / min; Wherein, the forming process is compression forming.

6. The preparation method according to claim 5, characterized in that The compression molding process includes: placing the inoculated bean dregs in a regular container and compressing and molding them using a hydraulic press.

7. The preparation method according to claim 5, characterized in that The fermentation temperature is 25-35℃, the humidity is 60-70%, and the fermentation time is 20-30h.

8. The preparation method according to claim 7, characterized in that The fermentation time is 22-26h.

9. The preparation method according to claim 7, characterized in that The fermentation process takes place in a place with air circulation and light.

10. The preparation method according to claim 7, characterized in that After fermentation is complete, freeze it.

11. The preparation method according to claim 1, characterized in that The preparation process of the bean dregs matrix comprises the steps of crushing, dehydrating, sterilizing and frying fresh bean dregs in sequence.

12. The preparation method according to claim 11, characterized in that The crushing is carried out using a colloid mill, and the particle size after crushing is controlled to be 0.2-0.3 mm.

13. The preparation method according to claim 11, characterized in that Dehydration is to place the material in a centrifuge, control the moisture content of the dehydrated bean dregs to 70-80%, and control the speed of the centrifuge to 800-1200r / min.

14. The preparation method according to claim 11, characterized in that Sterilization is carried out at a temperature of 115-125°C for 20-40 minutes using a steamer.

15. The preparation method according to claim 11, characterized in that The frying is carried out in a planetary frying pan, and the moisture content after frying is controlled to be 60-70%, the frying temperature is 70-80℃, and the frying time is 25-35min.

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