Preparation method of fermented bean curd
By diluting and separating the salinity of fermented bean curd, recycling flavor substances and mixing, the problem of excessive salinity is solved, and the effect of reducing salinity and retaining flavor is achieved.
Patent Information
- Application Number
- CN202510350479.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-24
- Publication Date
- 2025-05-06
AI Technical Summary
In the existing fermented bean curd production methods, in order to inhibit the growth of miscellaneous bacteria, a large amount of salt is needed, resulting in excessive fermented bean curd salt, affecting taste and health. At the same time, the use of low-salt fermentation technology will affect the flavor of fermented bean curd.
By obtaining the initial fermented bean curd, its salinity is diluted, it is separated into paste and liquid, the flavor substances in the liquid are recovered, and the target fermented bean curd is obtained after mixing, achieving salinity reduction and flavor retention.
It effectively reduces the salinity of fermented bean curd, avoids health problems and taste deviations caused by excessive salting, and retains the original flavor of fermented bean curd.
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Figure CN119924460A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of food processing, and in particular to a method for preparing fermented bean curd. Background Art
[0002] Fermented bean curd is a traditional Chinese food made from fermented tofu. The brewing process of fermented bean curd is complicated and time-consuming, requiring both pre-fermentation and post-fermentation, and the biochemical reactions involved are very complex. The flavor of fermented bean curd depends on the enzymes produced by the bacterial flora during the entire fermentation process, so the key to fermented bean curd production is to cultivate excellent strains during the fermentation process while inhibiting harmful bacteria.
[0003] In current industrial production, a large amount of salt is generally added to inhibit the growth of bacteria in fermented bean curd. However, adding a large amount of salt will cause the fermented bean curd to have a poor taste due to excessive salinity. The fermented bean curd produced according to the existing method has a salt content of 7 to 15 g per 100 grams, so that most of the finished fermented bean curd currently sold can only be used as pickles or as a seasoning. In addition, excessive salt content in food will affect human health and may cause kidney, cardiovascular, hypertension and other related diseases. If low-salt fermentation technology is used to improve the taste of fermented bean curd, it will inevitably affect the flavor of the fermented bean curd. For example, enzyme preparations are added during the production process or the strains in the fermentation process are changed to produce low-salt fermented bean curd. However, due to the addition of enzyme preparations or the change of strains, the fermentation environment of the fermented bean curd has changed, which directly affects the flavor of the fermented bean curd, resulting in a serious deviation in taste between the fermented bean curd prepared by this method and the traditional fermented bean curd.
[0004] Therefore, how to reduce the salinity of fermented bean curd while ensuring the flavor of the fermented bean curd is a problem that needs to be solved. Summary of the invention
[0005] The present application provides a method for preparing fermented bean curd to solve the problem that the existing fermented bean curd has a bad taste and is unhealthy.
[0006] According to one aspect of the present invention, there is provided a method for preparing fermented bean curd, comprising the following steps:
[0007] Obtaining initial fermented bean curd;
[0008] The salinity of the initial fermented bean curd is diluted to obtain a fermented bean curd suspension with a target salinity;
[0009] Separating the fermented bean curd suspension to obtain a separated paste and a separated liquid;
[0010] Recovering the flavor substances in the separated liquid to obtain a concentrated liquid containing the flavor substances;
[0011] The concentrated liquid and the separated paste are mixed to obtain the target fermented bean curd.
[0012] In one embodiment, obtaining an initial fermented bean curd comprises:
[0013] Inoculate mold on the surface of tofu embryo to obtain tofu embryo;
[0014] The tofu embryo is pre-fermented to obtain the fermented bean curd embryo;
[0015] pickling the fermented bean curd embryo to obtain pickled fermented bean curd;
[0016] The pickled fermented bean curd is subjected to a later stage fermentation to obtain the initial fermented bean curd.
[0017] In one embodiment, the initial fermented bean curd comprises a mixture of multiple finished fermented bean curds. In one embodiment, the salinity of the initial fermented bean curd is diluted, including: crushing and stirring the initial fermented bean curd, and adding a predetermined amount of water thereto to obtain a fermented bean curd suspension with a target salinity.
[0018] In one embodiment, the flavor substances in the separated liquid are recovered to obtain a concentrated liquid containing the flavor substances, comprising:
[0019] The salt and water in the separated liquid are filtered out to obtain the remaining concentrated liquid containing flavor substances.
[0020] In one embodiment, recovering the flavor substances in the separated liquid to obtain a concentrated liquid containing the flavor substances comprises at least one of the following steps:
[0021] Using a microfiltration processor to filter and separate the liquid to obtain a microfiltration membrane retentate liquid and a microfiltration membrane dialysis liquid;
[0022] Using an ultrafiltration processor to filter the microfiltration membrane dialysis liquid to obtain an ultrafiltration membrane retentate liquid and an ultrafiltration membrane dialysis liquid;
[0023] Using a nanofiltration processor to filter the ultrafiltration membrane dialyzed liquid to obtain a nanofiltration membrane retentate liquid and a nanofiltration membrane dialyzed liquid;
[0024] The concentrated liquid containing flavor substances includes at least one of a microfiltration membrane retentate liquid, an ultrafiltration membrane retentate liquid, and a nanofiltration membrane retentate liquid.
[0025] In one embodiment, the nanofiltration uses a nanofiltration membrane with a molecular weight cutoff of 70 to 90 Daltons.
[0026] In one embodiment, the method for separating the fermented bean curd suspension comprises at least one of a centrifugal separation method, a static separation method, a filtration method and a plate separation method.
[0027] In one embodiment, the method further comprises: adding seasoning to at least one of the concentrated liquid, the separated paste and the target fermented bean curd.
[0028] In one embodiment, the method further includes: sterilizing the target fermented bean curd, and aseptically filling the sterilized target fermented bean curd.
[0029] Compared with the prior art, this application has the following advantages:
[0030] In the method for preparing fermented bean curd provided by the present application, an initial fermented bean curd is first obtained, and the salinity of the initial fermented bean curd is diluted to obtain a fermented bean curd suspension of target salinity; after separating the fermented bean curd suspension, a separated paste and a separated liquid are obtained; then the flavor substances in the separated liquid are recovered to obtain a concentrated liquid containing the flavor substances, and finally, the concentrated liquid and the separated paste are mixed to obtain the target fermented bean curd. In this method, the initial fermented bean curd can be fermented bean curd produced by a high-salinity fermentation process. By diluting the salinity of the initial fermented bean curd, the salinity of the fermented bean curd can be reduced to the target salinity, thereby avoiding health problems and taste deviations that may be caused by excessive salinity of the fermented bean curd. At the same time, by separating the fermented bean curd suspension, recovering the flavor substances in the separated liquid, and mixing the concentrated liquid with the separated paste, the flavor of the target fermented bean curd can be ensured on the basis of reducing the salinity of the fermented bean curd.
[0031] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following specifically cites the preferred embodiments and describes them in detail with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] Figure 1 This is a flow chart of the preparation process of fermented bean curd provided in the embodiments of the present application;
[0033] Figure 2 This is a flow chart of the preparation process of the initial fermented bean curd provided in the examples of the present application. DETAILED DESCRIPTION
[0034] Many specific details are described in the following description to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present application, so the present application is not limited by the specific implementation disclosed below.
[0035] The terms used in one or more embodiments of this specification are only for the purpose of describing specific embodiments, and are not intended to limit one or more embodiments of this specification. The singular forms of "a", "said" and "the" used in one or more embodiments of this specification and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used in one or more embodiments of this specification refers to and includes any or all possible combinations of one or more associated listed items.
[0036] Figure 1 1 is a flow chart of a preparation process of fermented bean curd provided in an embodiment of the present application. Figure 1 As shown, a method for producing fermented bean curd comprises the following steps:
[0037] S1, obtaining initial fermented bean curd.
[0038] This step is used to obtain initial fermented bean curd, which may refer to fermented bean curd produced by a high-salinity fermentation process. "Initial" does not specifically refer to a certain type of fermented bean curd, but is only used to distinguish the processing steps of the processing object of this embodiment from the final product.
[0039] In this embodiment, the initial fermented bean curd can be a finished fermented bean curd or a mixture of multiple finished fermented bean curds. For example, the initial fermented bean curd can be a mixture of two or more finished fermented bean curds from different regions produced by the existing high-salinity fermentation process. That is, since the microbial flora suitable for growth in different regions are different, the flavor of fermented bean curd in each region is unique. In this embodiment, by mixing multiple finished fermented bean curds from different regions into initial fermented bean curd, the initial fermented bean curd contains multiple different flavors, thereby making the taste of the initial fermented bean curd rich and varied.
[0040] S2, diluting the salinity of the initial fermented bean curd to obtain a fermented bean curd suspension with a target salinity.
[0041] After the initial fermented bean curd is obtained in the above step, this step is used to dilute the salinity of the initial fermented bean curd to obtain a fermented bean curd suspension of target salinity. Specifically, the initial fermented bean curd can be crushed and stirred evenly, and a predetermined amount of water is added thereto to obtain a fermented bean curd suspension of target salinity. The target salinity can be set according to actual needs. In this embodiment, the target salinity can be any value between 0.5% and 5% (e.g., 1.5%). The salinity within this range is an appropriate salinity that can meet the taste and health requirements of the fermented bean curd.
[0042] In another embodiment, a gradient dilution method can also be used to gradually reduce the salinity of the initial fermented bean curd to obtain a fermented bean curd suspension of target salinity. For example, after the initial fermented bean curd is crushed and stirred evenly, a first predetermined amount of water is first added thereto and stirred evenly to obtain a fermented bean curd suspension of intermediate concentration and detect its salinity. The second predetermined amount of water to be added is calculated based on the detected salinity, target salinity, etc., and the dilution and stirring operations are repeated until the fermented bean curd suspension of target concentration is obtained. The fermented bean curd suspension of target salinity obtained by the gradient dilution method in this embodiment can better retain the flavor of the fermented bean curd, while obtaining a fermented bean curd suspension with a more precise salinity.
[0043] S3, separating the fermented bean curd suspension to obtain a separated paste and a separated liquid.
[0044] After obtaining the fermented bean curd suspension of target salinity in the above step, this step is used to separate the fermented bean curd suspension into a separated paste and a separated liquid. The separated paste is the solid in the fermented bean curd suspension, which can retain some flavor substances of the fermented bean curd. Other flavor substances of the fermented bean curd are dissolved in the separated liquid. The separated liquid also includes a large amount of dissolved salt and protein, fat, carbohydrates, organic acids, etc., among which the flavor substances are the main source of the unique flavor and aroma of the fermented bean curd, mainly from the metabolism of microorganisms during the fermentation process and the seasonings added during the pickling process, including protein hydrolysates such as amino acids and peptides, lipid hydrolysates such as fatty acids and glycerol, sugars and alcohols, and organic acids, esters, aldehydes and ketones produced during the fermentation process. The salinity of the separated paste and the separated liquid obtained by separation is maintained at the above target salinity.
[0045] In this embodiment, the fermented bean curd suspension may be separated by at least one of centrifugal separation, static separation, filtration, and plate separation methods.
[0046] For example, when using centrifugal separation to separate fermented bean curd suspension, a horizontal spiral sedimentation centrifuge can be used as the separation equipment. First, the drum speed and spiral difference of the centrifuge are set according to the viscosity of the fermented bean curd suspension. Then, the fermented bean curd suspension is injected into the horizontal spiral centrifuge. Under the action of the centrifugal force generated by the high-speed rotation of the main machine, the solid phase separation paste with a larger specific gravity and the liquid separation liquid with a relatively smaller specific gravity are separated. The separation paste and the separation liquid are respectively stored in sterile containers.
[0047] When using the plate separation method to separate the fermented bean curd suspension, a plate and frame filter press can be used as the separation equipment. The predetermined pressure is set and the filter cloth pore size is selected according to the viscosity of the fermented bean curd suspension. The fermented bean curd suspension is injected into the feed port of the plate and frame filter press. Under the action of the predetermined pressure, the separation paste and the separation liquid are separated, and the separation paste and the separation liquid are respectively stored in sterile containers.
[0048] For another example, the fermented bean curd suspension can be separated by a combination of centrifugal separation and plate separation. Specifically, after the fermented bean curd suspension is separated by a horizontal spiral sedimentation centrifuge, a first separated liquid and a first separated paste are obtained. The first separated liquid is then injected into a plate and frame filter press for secondary separation to obtain a second separated liquid and a second separated paste. The first separated paste and the second separated paste are mixed and stored in a sterile container, and the second separated liquid is also stored in a sterile container.
[0049] S4, recovering the flavor substances in the separated liquid to obtain a concentrated liquid containing the flavor substances.
[0050] After the separation paste and separation liquid are obtained in the above steps, this step is used to recover the flavor substances in the above separation liquid to obtain a concentrated liquid containing flavor substances. The salinity of the concentrated liquid is the same as the salinity of the above separation paste, both of which are target salinity.
[0051] In this embodiment, filtration processes such as microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and macroporous resin filtration (Macroporous Resin Filtration) can be used to filter out salt and water in the separated liquid to obtain the remaining concentrated liquid containing flavor substances. Among them, microfiltration, ultrafiltration and nanofiltration are all membrane separation technologies driven by pressure. The pore size range of the filter membrane corresponding to the microfiltration process is 0.1 to 10 microns, and the operating pressure is about 0.1 to 0.5 MPa. It is mainly used to separate suspended particles, bacteria and macromolecules; the pore size range of the filter membrane corresponding to the ultrafiltration process is 1 to 100 nanometers, and the operating pressure is about 0.2 to 1.0 MPa. It is mainly used to separate macromolecules such as proteins, polysaccharides, colloids, etc.; the pore size range of the filter membrane corresponding to the nanofiltration process is 0.1 to 1 nanometer, and the operating pressure is about 0.5 to 3.0 MPa. It is mainly used to separate small molecular organic matter; macroporous resin filtration is an adsorption separation technology based on the porous structure and surface chemical properties of resin materials, and the corresponding resin pore size range is 50 to 1000 nanometers.
[0052] Since the molecular weight of salt is 58.5 Daltons, while the molecular weight of amino acids in flavor substances is between 75 and 204 Daltons, the molecular weight of polypeptides is generally greater than 200 Daltons, and the molecular weight of lipids is generally greater than 300 Daltons, a filter membrane with an appropriate pore size and a corresponding filtering method can be selected for filtering according to the type of flavor substances to be retained. In this embodiment, at least one of a plurality of filtering processes can be used to recover the flavor substances in the separated liquid, and correspondingly, the concentrated liquid containing the flavor substances includes at least one of a plurality of filtered membrane retained liquids such as microfiltration membrane retained liquid, ultrafiltration membrane retained liquid, and nanofiltration membrane retained liquid.
[0053] Specifically, in one embodiment, only one filtering process can be used to recover flavor substances. For example, only a microfiltration processor is used to filter the separated liquid to recover the flavor substances in the separated liquid. Specifically, a microfiltration processor with a microfiltration membrane pore size greater than 0.1 micron is used to filter the separated liquid to obtain a microfiltration membrane retained liquid containing flavor substances and a microfiltration membrane dialyzed liquid containing a large amount of salt and water, and the microfiltration membrane retained liquid is recovered into a first sterile recovery tank, and the microfiltration membrane dialyzed liquid is injected into a salt water tank. For another example, when only a nanofiltration process is used to recover flavor substances, a nanofiltration membrane with a molecular weight cutoff of 70 to 90 Daltons (pore size between 70 and 90 Daltons) can be selected for filtration to retain flavor substances such as amino acids, polypeptides, esters, etc. with a molecular weight greater than 90 Daltons. Flavor substances with a molecular weight greater than 90 Daltons can be retained on the nanofiltration membrane, while salt and water pass through the nanofiltration pores to become nanofiltration membrane dialyzate.
[0054] In another embodiment, the flavor substances in the separated liquid can be recovered by combining two filtration processes, for example, the flavor substances in the separated liquid can be recovered by combining the following microfiltration and ultrafiltration processes: using a microfiltration processor to filter the separated liquid, for example, using a microfiltration processor with a microfiltration membrane pore size greater than 0.1 micron to filter the separated liquid, to obtain a microfiltration membrane retained liquid and a microfiltration membrane dialysis liquid containing flavor substances, and the microfiltration membrane retained liquid can be recovered to a first sterile recovery tank; and then using an ultrafiltration processor to filter the above-mentioned microfiltration membrane dialysis liquid, for example, using an ultrafiltration processor with a retention molecular weight of 1000 to 500000 Daltons to filter the above-mentioned microfiltration membrane dialysis liquid, to obtain an ultrafiltration membrane retained liquid containing flavor substances and an ultrafiltration membrane dialysis liquid containing a large amount of salt and water, and the ultrafiltration membrane retained liquid can be recovered to a second sterile recovery tank, and the ultrafiltration membrane dialysis liquid is injected into a brine tank.
[0055] In another embodiment, the flavor substances in the separated liquid can be recovered by combining multiple filtration processes in a stepwise manner, for example, the flavor substances in the separated liquid can be recovered by combining microfiltration, ultrafiltration and nanofiltration as shown below: first, the separated liquid is filtered using a microfiltration processor, for example, a microfiltration processor with a microfiltration membrane pore size greater than 0.1 micron can be used to filter the separated liquid to obtain a microfiltration membrane retained liquid and a microfiltration membrane dialyzed liquid, and the microfiltration membrane retained liquid is recovered into a first sterile recovery tank; then, the above-mentioned microfiltration membrane dialyzed liquid is filtered using an ultrafiltration processor, for example, a microfiltration processor with a molecular weight cutoff of 100 can be used. The ultrafiltration processor with a molecular weight of 0 to 500,000 Daltons filters the above-mentioned microfiltration membrane dialysis liquid to obtain ultrafiltration membrane retained liquid and ultrafiltration membrane dialysis liquid, which can be recovered into the second sterile recovery tank; finally, the above-mentioned ultrafiltration membrane dialysis liquid is filtered using a nanofiltration processor. For example, a nanofiltration processor with a molecular weight cutoff of 70 to 1,000 Daltons can be used to filter the above-mentioned ultrafiltration membrane dialysis liquid to obtain a nanofiltration membrane retained liquid containing flavor substances and a nanofiltration membrane dialysis liquid containing a large amount of salt and water. The nanofiltration membrane dialysis liquid can be injected into a brine tank, and the nanofiltration membrane retained liquid is recovered into the third sterile recovery tank. This method uses different filter membrane pore sizes for step-by-step filtration, which can recover the flavor substances in the separated liquid to the greatest extent, and obtain microfiltration membrane retained liquid, ultrafiltration membrane retained liquid and nanofiltration membrane retained liquid containing different flavor substances.
[0056] In this embodiment, appropriate amounts of microfiltration membrane retained liquid, ultrafiltration membrane retained liquid, and nanofiltration membrane retained liquid can be selected according to preset requirements. For example, it can be microfiltration membrane retained liquid, ultrafiltration membrane retained liquid, or nanofiltration membrane retained liquid, or it can be part of the microfiltration membrane retained liquid, part of the ultrafiltration membrane retained liquid, or part of the nanofiltration membrane retained liquid.
[0057] S5, mixing the concentrated liquid and the separated paste to obtain the target fermented bean curd.
[0058] After the concentrated liquid containing flavor substances is obtained through the above steps, this step is used to mix the concentrated liquid with the above separated paste to obtain the target fermented bean curd. For example, the concentrated liquid and the separated paste obtained after the treatment in step S3 can be mixed completely, and the target fermented bean curd finally obtained can restore the flavor of the fermented bean curd to the greatest extent. Alternatively, the above concentrated liquid and the separated paste can be mixed in a preset ratio to obtain target fermented bean curd with different flavor concentrations.
[0059] In this embodiment, predetermined types of seasonings can be added to the target fermented bean curd during or after the target fermented bean curd is prepared, so as to enrich the taste level of the fermented bean curd, enhance the overall flavor or impart a unique flavor. For example, seasonings can be added to the concentrated liquid and / or the separated paste after step S4 is completed, or predetermined types of seasonings can be added to the target fermented bean curd after the concentrated liquid and the separated paste are mixed to obtain the target fermented bean curd.
[0060] Furthermore, the state and / or shape of the target fermented bean curd can be set based on individual needs. For example, after the concentrated liquid and the separated paste are mixed, they can be shaped and dried to obtain a solid fermented bean curd of a preset shape to meet the individual needs of users.
[0061] In another embodiment, if Figure 2 As shown, the initial fermented bean curd in step S1 above can also be prepared by the following steps:
[0062] S101, microorganism inoculation is performed on the surface of the tofu embryo to obtain the tofu embryo. Specifically, the microorganism inoculation can be performed by spraying a culture solution containing molds or bacteria on the surface of the tofu embryo by a machine or by immersing the tofu embryo in a culture solution containing molds or bacteria. The inoculated mold can be one or at least two of Mucor spp., Rhizopus spp., Lactic Acid Bacteria, Monascus spp., Bacillus spp., yeast (such as Saccharomyces cerevisiae) or other molds. For example, the inoculated mold can be a mixed strain of Mucor and yeast. The above two molds are mixed and inoculated on the surface of the tofu embryo to enrich the flavor of fermented bean curd and increase the aroma of fermented bean curd.
[0063] In this embodiment, the tofu embryo can be square, rectangular or any other shape, and the tofu embryo can be placed in any manner, thereby improving the inoculation efficiency of the tofu embryo.
[0064] S102, pre-fermenting the tofu embryos inoculated with the microorganisms to obtain fermented bean curd. Specifically, the tofu embryos inoculated with molds can be placed in a fermentation container for pre-fermentation. During the pre-fermentation, the surface of the tofu embryos is gradually covered with hyphae to form fermented bean curd.
[0065] S103, pickling the fermented bean curd with mycelium on the surface to obtain pickled fermented bean curd. Specifically, a pickle consisting of salt, liquor, etc. can be added to the fermented bean curd after the early stage for pickling. For example, by adding a large amount of salt, a high-salinity fermentation environment of the fermented bean curd can be created, thereby ensuring the flavor of the fermented bean curd.
[0066] S104, subjecting the pickled fermented bean curd to late fermentation to obtain initial fermented bean curd. Specifically, the pickled fermented bean curd can be placed in a sealed environment for late fermentation. During the late fermentation process, the flavor and texture of the fermented bean curd are further improved, forming a unique taste and aroma. In one embodiment, the pickled fermented bean curd is late fermented in a sealed environment, and the sealed environment can be a sealed bottle or a sealed jar, or a sealed bag or a sealed container of any shape. In this embodiment, the pickled fermented bean curd can be directly transferred to the sealed environment by a machine for late fermentation without maintaining a specific shape of the pickled fermented bean curd.
[0067] The traditional fermented bean curd preparation process generally includes: inoculation, block placement, pre-fermentation, hair rubbing, pickling, bottling, post-fermentation and other processes. Among them, the block placement process is to cut the tofu into blocks of uniform size and place them neatly, which is mainly used to maintain the shape of the tofu blocks during the subsequent fermentation and processing process to avoid mutual adhesion or breakage; the hair rubbing process is to flatten the mold on the surface of the tofu blocks covered with mold, so that the growing mold hyphae are smeared tightly on the surface of the fermented bean curd to form a layer of "skin", which is conducive to the shape of the fermented bean curd in the subsequent processing process and is not easy to break. In addition, the hair rubbing can break the hyphae adhered between the molds, separate the tofu blanks from each other, and avoid the tofu blocks from sticking together during pickling or other operations, which affects the quality and appearance of the fermented bean curd; the bottling process is used to put the fermented bean curd blanks neatly into the bottle, for example, placing them one by one in concentric circles along the bottle wall. In this process, it is necessary to avoid the side without hyphae facing down, and the fermented bean curd should be placed to avoid breaking, so as to ensure the appearance and quality of the fermented bean curd. It can be seen that the above-mentioned block arranging, hair rolling and bottling processes are mainly used to keep the appearance of fermented bean curd in a complete block shape. In the present embodiment, since the target fermented bean curd finally obtained is a mixture of concentrated liquid and separated paste, there is no requirement on the shape of the fermented bean curd (including the initial fermented bean curd and the final target fermented bean curd). Therefore, in the processing link of the initial fermented bean curd, the above-mentioned block arranging, hair rolling and bottling processes can be omitted, and only the basic processes such as inoculation, pre-fermentation, pickling and post-fermentation corresponding to the above-mentioned steps S101-S104 are retained, which can effectively improve the processing efficiency of the initial fermented bean curd and simplify the process flow.
[0068] Furthermore, in the above-mentioned traditional fermented bean curd preparation process, in order to keep the fermented bean curd in a complete block shape, the above-mentioned block placement, hair rolling and bottling processes are mostly completed manually, which is easy to cause bacterial contamination during the production process. Figure 2 The preparation process of the initial fermented bean curd shown in the figure eliminates the necessary steps of arranging blocks, rubbing hairs and bottling in the traditional preparation process, and there is no need to maintain the final shape of the fermented bean curd. Therefore, the preparation process of the initial fermented bean curd can be automated by mechanical equipment without human intervention. While improving the processing efficiency of the initial fermented bean curd and simplifying the process flow, it avoids external contamination that may be caused by manual operation.
[0069] In this embodiment, after the target fermented bean curd is obtained through step S5, the target fermented bean curd needs to be sterilized and aseptically filled. For example, the sterilized target fermented bean curd can be aseptically filled in small portions to facilitate single consumption and avoid cross contamination during consumption.
[0070] The method for preparing fermented bean curd provided in this embodiment comprises the following steps: firstly obtaining an initial fermented bean curd, and diluting the salinity of the initial fermented bean curd to obtain a fermented bean curd suspension of target salinity; after separating the fermented bean curd suspension, obtaining a separated paste and a separated liquid; then recovering the flavor substances in the separated liquid to obtain a concentrated liquid containing the flavor substances; and finally, mixing the concentrated liquid with the separated paste to obtain the target fermented bean curd. In this method, the salinity of the fermented bean curd can be reduced to the target salinity by diluting the salinity of the initial fermented bean curd, thereby avoiding health problems and taste deviation problems caused by excessive salinity of the fermented bean curd. At the same time, by separating the fermented bean curd suspension, recovering the flavor substances in the separated liquid, and mixing the concentrated liquid with the separated paste, the salinity of the fermented bean curd can be diluted to a low salinity suitable for consumption, while maintaining the flavor of the fermented bean curd. Furthermore, since there is no need to keep the target fermented bean curd in a complete block shape, the processes of rubbing hair, arranging blocks, bottling, etc., which are used to keep the target fermented bean curd in a complete block shape, can be omitted in the production of the initial fermented bean curd, which can effectively improve the processing efficiency of the initial fermented bean curd and simplify the process flow; and, since there is no need for manual intervention, external contamination that may be caused during manual operation can be avoided, and the entire fermented bean curd preparation process can be fully automated, greatly improving the production efficiency of the fermented bean curd.
[0071] Although the present application is disclosed as above in the form of a preferred embodiment, it is not intended to limit the present application. Any technical personnel in this field may make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be based on the scope defined by the claims of the present application.
Claims
1. A method for preparing fermented bean curd, characterized in that: The following steps are involved: Obtaining initial fermented bean curd; diluting the salinity of the initial fermented bean curd to obtain a fermented bean curd suspension with a target salinity; Separating the fermented bean curd suspension to obtain a separated paste and a separated liquid; Recovering the flavor substances in the separated liquid to obtain a concentrated liquid containing the flavor substances; The concentrated liquid and the separated paste are mixed to obtain the target fermented bean curd.
2. The method for preparing fermented bean curd according to claim 1, characterized in that: The method of obtaining the initial fermented bean curd comprises: Inoculating microorganisms on the surface of tofu embryos to obtain tofu embryos; Pre-fermenting the tofu embryo to obtain fermented bean curd embryo; pickling the fermented bean curd embryo to obtain pickled fermented bean curd; The pickled fermented bean curd is subjected to a later stage fermentation to obtain the initial fermented bean curd.
3. The method for preparing fermented bean curd according to claim 1, characterized in that: The initial fermented bean curd comprises a mixture of a plurality of finished fermented bean curds.
4. The method for preparing fermented bean curd according to claim 1, characterized in that: The salinity of the initial fermented bean curd is diluted, including: crushing and evenly stirring the initial fermented bean curd, and adding a predetermined amount of water thereto to obtain the fermented bean curd suspension with a target salinity.
5. The method for preparing fermented bean curd according to claim 1, characterized in that: Recovering the flavor substances in the separated liquid to obtain a concentrated liquid containing the flavor substances comprises: The salt and water in the separated liquid are filtered out by filtering to obtain the remaining concentrated liquid containing the flavor substances.
6. The method for preparing fermented bean curd according to claim 1, characterized in that: Recovering the flavor substances in the separated liquid to obtain a concentrated liquid containing the flavor substances comprises at least one of the following steps: Using a microfiltration processor to filter the separated liquid to obtain a microfiltration membrane retentate liquid and a microfiltration membrane dialyzed liquid; Using an ultrafiltration processor to filter the microfiltration membrane dialysis liquid to obtain ultrafiltration membrane retentate liquid and ultrafiltration membrane dialysis liquid; Using a nanofiltration processor to filter the ultrafiltration membrane dialysis liquid to obtain a nanofiltration membrane retentate liquid and a nanofiltration membrane dialysis liquid; Correspondingly, the concentrated liquid containing flavor substances includes at least one of microfiltration membrane retentate liquid, ultrafiltration membrane retentate liquid and nanofiltration membrane retentate liquid.
7. The method for preparing fermented bean curd according to claim 6, characterized in that: in, The nanofiltration uses a nanofiltration membrane with a molecular weight cutoff of 70 to 90 Daltons.
8. The method for preparing fermented bean curd according to claim 1, characterized in that: The method for separating the fermented bean curd suspension comprises at least one of a centrifugal separation method, a static separation method, a filtration method and a plate separation method.
9. The method for preparing fermented bean curd according to claim 1, characterized in that: The method further includes adding seasoning to at least one of the concentrated liquid, the separated paste, and the target fermented bean curd.
10. The method for preparing low-salt paste-like fermented bean curd according to claim 1, characterized in that: The method further comprises: sterilizing the target fermented bean curd, and aseptically filling the sterilized target fermented bean curd.