Preparation method of low-salt thick broad-bean sauce and fermentation tank structure adopted for fermentation

Abstract

The invention provides a preparation method of low-salt thick broad-bean sauce. The preparation method comprises the following steps: S1, preparing salted chilies; s2, preparing sweet bean halves; according to the method, the salted chilies are adopted to replace chilies, and specific fermentation equipment is adopted, so that the fermentation time is shortened, the salinity of the thick broad-bean sauce is reduced, different strains are added in different stages to enrich the flavor of the thick broad-bean sauce, and the chilies are added in stages to be combined, so that the taste can be enriched, and fermentation is facilitated; according to the three-stage fermentation process, the fermentation time and temperature can be accurately controlled, fermentation is facilitated, a self-designed fermentation tank is adopted, the fermentation temperature is effectively controlled, substrates and enzymes are conveniently supplemented in time, the thick broad-bean sauce which is richer and healthier in taste is produced, the fermentation time can be effectively shortened, and good economic benefits are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of food, and in particular relates to a method for preparing low-salt bean paste and a fermentation tank structure used for fermentation. Background Art

[0002] Doubanjiang is a traditional fermented condiment. Its main raw materials are broad beans and red peppers, supplemented by salt and flour. It has the characteristics of bright red color, delicious taste and rich sauce aroma, and is known as the "soul of Sichuan cuisine". The traditional fermentation method is to ferment in a long pool, strictly following the method of sun drying on sunny days, covering on rainy days, turning during the day, and exposing at night. Generally, it needs to be turned over and dried once a day until fermentation is mature. The general fermentation time is 10 to 12 months. The fermentation time is too long, the production cost is high, which is not conducive to the capital flow of the enterprise, and the fermentation time is long, which is easily affected by external microorganisms, making the product quality unstable. What is more worthy of attention is that the salt content of commercially available Doubanjiang is high, generally around 20%. With the improvement of economic level and the improvement of people's quality of life, more and more consumers pay more attention to their health, and at the same time, more and more consumers pay more attention to salt intake and refuse high-salt diet. Therefore, reducing the salt content of Doubanjiang and shortening the fermentation time are problems to be solved in this field. Summary of the invention

[0003] In order to solve the problems in the prior art, the present invention provides a low-salt bean paste and a method for reducing the salt content of the bean paste and shortening the fermentation cycle. The present invention is achieved through the following technical solutions:

[0004] The present invention provides a method for preparing low-salt bean paste, comprising the following steps:

[0005] S1 Preparation of salted peppers:

[0006] S11: taking mature Erjingtiao fresh or dried peppers, trimming the Erjingtiao fresh peppers and leaving the stalks, washing or drying them, and removing moisture from the surface; and rehydrating the Erjingtiao dried peppers by adding 3 to 8 times of water; taking mature Xiaoxiaola fresh or dried peppers, and pre-treating them in the same manner as above;

[0007] S12: Weigh the processed Erjingtiao and Xiaojiao according to a weight ratio of 1 to 2:1, soak them in warm water of 60-80°C, which is 5 to 8 times the total mass of the peppers, and then add 20 to 25% edible salt, 5 to 8% 52° liquor, and 2 to 5% white sugar based on the total mass of the peppers and water, stir evenly, and naturally ferment in a closed, cool, and ventilated place for 20 to 30 days to obtain salted peppers, cut the salted peppers into pieces for later use, and store the salted pepper water for later use;

[0008] S2 Preparation of sweet bean paste:

[0009] S21: Select dry broad bean stalks, remove impurities and moldy broad bean stalks, soak the selected dry broad bean stalks in water, add water to cover the surface of the dry broad bean stalks by 10 to 15 cm, stir evenly, remove broken shells and impurities floating on the surface, soak for 1 to 2.5 hours, and remove water after a line of white core is slightly visible on the cross section of the broad bean stalks, thereby obtaining the soaked broad bean stalks;

[0010] S22: mixing the flour and the seed koji uniformly, wherein the amount of the seed koji added is 1.2-3.5% of the total weight of the flour, and the seed koji is selected from any one or more of Aspergillus oryzae, Aspergillus nige, and Saccharomyces cerevisiae; further, the seed koji is composed of Aspergillus oryzae, Aspergillus nige, and Saccharomyces cerevisiae, and the mass ratio thereof is 6-8:1-2:1-2;

[0011] S23: mixing the flour mixed with the seed koji and the broad bean petals soaked in S21 and stirring evenly, so that the flour is evenly coated on the surface of the broad bean petals, and the mass ratio of the flour to the dry broad bean petals is 1-5:10-15, so as to obtain the inoculated broad bean petals;

[0012] S24: transferring the inoculated broad bean petals into a koji bed, so that the broad bean petals are uniform and have a flat surface, with a thickness of about 15 to 25 cm, and ventilating and koji making at 32 to 36° C. for 36 to 48 hours to obtain broad bean petals koji;

[0013] S25: breaking the broad bean scallops into pieces, adding the salted chili water prepared in S12, wherein the salted chili water accounts for 35-45% of the total mass of the scallops, and adding 2-3% of the total mass of dried chili peppers, compacting the surface layer, and then covering the scallops with 3-4% of the total mass of edible salt, and sealing with food-grade plastic, and fermenting at 35-55° C. for 30-60 days to obtain sweet broad bean scallops;

[0014] S3 Preparation of bean paste:

[0015] S31: placing the sweet bean paste prepared in S25 and the salted chili pieces prepared in S12 in a fermentation tank, mixing and stirring evenly, wherein the mass ratio of the sweet bean paste to the salted chili pieces is 3-5:8-14, and simultaneously inoculating Saccharomyces cerevisiae brewer's yeast, wherein the inoculation amount of the brewer's yeast is 2-5% of the total mass of the sweet bean paste and the salted chili pieces, to obtain bean paste fermented rice;

[0016] S32: The fermented bean curd obtained in 31 is placed in a fermentation tank for fermentation. The fermentation is carried out in three stages. The first stage is an early stage, which lasts for about 20 to 30 days, the fermentation temperature is 35 to 38°C, and stirring is performed 1 to 3 times a day, each time for 3 to 5 minutes; the second stage is a mid-term stage, which lasts for 30 to 40 days, the fermentation temperature is 30 to 35°C, and stirring is performed 1 to 2 times a day, each time for 3 to 5 minutes. On the first day of the mid-term fermentation process, the salted chili pieces prepared in S12 are added, and the added amount is 1 to 3% of the mass of the bean curd when the early stage is completed. The same mass of salted chili pieces is added every 10 days thereafter; the third stage is a late fermentation stage, and on the first day of the late fermentation, 0.5-1.5% of the mass of the bean curd when the mid-term stage is completed is added to the Lactobacillus helveticusCGMCC No.25010, and 1-2% of the mass of the fermented bean paste when the middle stage is completed. The late fermentation time is 40-60 days, the fermentation temperature is 30-32°C, stirring 1-2 times every other day, each time for 3-5 minutes. After the fermentation is completed, low-salt fermented bean paste is obtained.

[0017] The Lactobacillus helveticus used in the present invention has been deposited in the General Microbiology Center of the China National Microbiological Culture Collection Administration on June 6, 2022, with the address being No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, with the deposit number: CGMCC No. 25010.

[0018] The second aspect of the present invention provides a fermentation tank structure matched with the preparation method of the low-salt bean paste, comprising:

[0019] A motor (10), a ground fixing device (20), a fermentation tank body (30), a stirring assembly (40), and a detachable heat-insulating layer (50), wherein the fermentation tank body (30) is mounted on the ground fixing device (20), the stirring assembly (40) is rotatably mounted in the fermentation tank body (30), the motor (10) is fixedly connected to the stirring assembly (40) and drives the stirring assembly (40) to rotate; the fermentation tank body (30) is provided with a feed inlet (31) and a discharge outlet (32) at the top and bottom, respectively, the stirring assembly (40) comprises a transmission shaft (41) and a stirring paddle arranged on the transmission shaft (41), the detachable heat-insulating layer (50) is detachably mounted on the outside of the fermentation tank body (30), and a plurality of heating tubes (51) are arranged in the detachable heat-insulating layer (50).

[0020] Furthermore, the stirring paddle comprises a straight stirring paddle (42) and a spiral stirring paddle (43), and the straight stirring paddle (42) and the spiral stirring paddle (43) are arranged on the transmission shaft (41).

[0021] Furthermore, the spiral stirring paddle (43) is arranged at the middle of the transmission shaft (41), and the straight stirring paddle (42) is arranged on both sides of the spiral stirring paddle (43).

[0022] Furthermore, the fermentation tank body (30) is provided with a filling port.

[0023] Furthermore, the fermentation tank body (30) is made of stainless steel, and a graphene layer is arranged inside the fermentation tank body (30).

[0024] Furthermore, the fermentation tank body (30) is arranged transversely along a parallel direction.

[0025] Furthermore, a detachable food-grade transmission pipeline is provided in the filling port (60).

[0026] Furthermore, a control panel is provided on the fermentation tank body (30), and the control panel is provided with a temperature control key, a temperature display, a stirring control key and a stirring control display. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the fermentation tank structure of the present invention;

[0028] 10. Motor; 20. Ground fixing device; 30. Fermentation tank body; 31. Feed inlet; 32. Discharge outlet; 40. Stirring assembly; 41. Drive shaft; 42. Straight stirring paddle; 43. Spiral stirring paddle; 50. Removable insulation layer; 51. Heating tube; 60. Filling port.

[0029] Beneficial Effects

[0030] 1. Effectively shorten the fermentation cycle: (1) The present invention uses salted peppers instead of pepper fermented mash to ferment, shortening the original fermentation time of pepper fermented mash from 2 to 3 months to 20 to 30 days of natural fermentation of salted peppers, greatly shortening the fermentation cycle;

[0031] 2. Effectively reduce the salt content of bean paste: in the present invention, edible salt is added only in the process of salting peppers and sealing the koji, and no additional edible salt is added during the fermentation of sweet bean paste and bean paste, so that the salt content of the bean paste product of the present invention is well reduced. The salt content of the low-salt bean paste product obtained by the present invention is about 6-8%, which is more than 50% lower than the salt content of 18-20% of commercial bean paste;

[0032] 3. Adding different strains of bacteria at different stages to enrich the flavor of bean paste: (1) In the present invention, brewer's yeast is introduced into both the sweet bean paste koji making process and the bean paste fermentation process. The introduction of brewer's yeast can effectively utilize the reducing sugar in the system to generate alcohol substances, giving the bean paste the aroma of alcohol and wine. It can not only prevent the growth of spoilage microorganisms and inhibit miscellaneous bacteria, but also generate ester aroma components with acid compounds, enriching the flavor of the bean paste. In addition, the introduction of brewing yeast can also secrete some proteases during the metabolic process of the entire system, and synergize with the proteases during koji making to increase the content of amino acid nitrogen, thereby increasing the umami substances in the final product; (2) The present invention introduces Lactobacillus helveticus in the late fermentation of bean paste. Lactobacillus helveticus produces lactic acid during the metabolic process of the system, which reduces the pH value of the system and promotes the growth of brewing yeast. However, when there are too many yeasts, a large amount of ethanol products can inhibit the growth of Lactobacillus helveticus. There is both interaction and mutual influence between them. Therefore, adding Lactobacillus helveticus in the late fermentation of bean paste is a very good process point. At this time, the number of yeasts in the system is much less than that in the early fermentation of bean paste. Lactobacillus helveticus needs to be added to stimulate metabolism, so that brewing yeast can continue to produce ethanol to inhibit the growth of miscellaneous bacteria. At the same time, the addition of Lactobacillus helveticus will also stimulate the formation of ester substances, making the product more flavorful;

[0033] 4. Adding the pepper combination in stages can enrich the taste and facilitate the fermentation process: (1) The present invention adds a small amount of salted pepper blocks every 10 days in the middle stage of fermentation of bean paste, which can supplement the fermentation substrate in the system and make the final product of fermented bean paste unique in flavor and more prominent in spicy taste; (2) The present invention adds dried peppers during the fermentation process of sweet bean paste and the late stage of fermentation of bean paste, which can well balance the moisture in the system and is beneficial to the smooth progress of the entire fermentation; (3) The salted peppers of the present invention use a mixture of erjingtiao and millet pepper, which makes the spicy taste of the product richer; at the same time, the white wine and white sugar added during the salting process of the peppers have a good antibacterial effect during the natural fermentation process of the salted peppers, and at the same time give the salted peppers a richer and softer taste; (4) The erjingtiao and millet peppers in the present invention are both pre-treated by retaining the pedicles, which can better allow salt, white wine and sugar to enter the peppers. In addition, the salted peppers in the present invention can be selected from fresh peppers or dried peppers for rehydration, which is not restricted by season and can be produced at any time;

[0034] 5. The three-stage fermentation process can accurately control the fermentation time and temperature, which is conducive to fermentation: the three-stage fermentation of the bean paste in the present invention is carried out in a fermentation tank, which can more accurately control the fermentation temperature and stirring time, create a more favorable fermentation environment for the anaerobic fermentation of Lactobacillus helveticus and Saccharomyces cerevisiae, and also create better conditions for other microorganisms and enzyme systems in the environment, produce more metabolites, and enrich the aroma and taste of the product. Although Lactobacillus helveticus is a facultative anaerobic bacterium and can tolerate a certain amount of oxygen, it grows better under anaerobic conditions and produces more lactic acid; although Saccharomyces cerevisiae is also a facultative anaerobic microorganism, it mainly grows and reproduces under aerobic conditions, and can only ferment and produce ethanol under anaerobic conditions. Fermentation in a fermenter can effectively isolate oxygen from the air, and the effect is much better than the traditional open fermentation with salt sealing. The traditional fermentation stirring process takes a long time and brings in more oxygen, while the stirring efficiency in the fermenter is higher and the time used is shorter, only 3-5 minutes. Because the oxygen brought in by the stirring of the fermenter is also less, the anaerobic environment of fermentation can be better maintained, allowing the microbial metabolites in the previous fermentation system to further generate organic acids and ethanol, and further produce phenolic and aldehyde metabolites in conjunction with other microorganisms, accelerating the fermentation process and forming unique flavor substances for the bean paste.

[0035] 6. The present invention adopts a self-designed fermentation tank, which has the following advantages: (1) The inner wall of the fermentation tank in the present invention is coated with a layer of graphene material. The graphene material has excellent thermal conductivity and can dissipate heat energy well into the fermented material, thereby increasing the reaction rate and preventing uneven heating due to part of the material contacting the tank wall during the static fermentation process. In addition, the graphene material has good anti-adhesion properties, which can reduce the deposition of reaction materials or products on the inner wall of the fermentation tank, making it convenient for cleaning and sanitation; (2) The filling port of the fermentation tank in the present invention is built with a detachable food-grade delivery pipe, which can directly transfer the substrate and bacterial system supplemented during the fermentation process to the top of the spiral stirring paddle, and add the supplementary substrate and enzyme system while stirring, so that the supplemented materials and enzyme system can be more evenly dispersed in the system. DETAILED DESCRIPTION

[0036] The present invention is further described below. The following examples are only used to more clearly illustrate the technical solution of the present invention, and are not intended to limit the protection scope of the present invention.

[0037] (I) Embodiment

[0038] Example 1

[0039] 1. Prepare salted peppers:

[0040] (1) Take mature fresh Erjingtiao peppers, trim the Erjingtiao peppers and keep the stems, wash them clean or dry them in the air without any moisture on the surface; take mature Xiaoxiaola fresh peppers and pre-treat them in the same way as above.

[0041] (2) Weigh the processed Erjingtiao and Xiaomi La in a ratio of 1:1; soak the peppers in 60°C warm water that is 5 times the total weight of the peppers, add 20% of edible salt, 5% of 52° liquor, and 2% of white sugar based on the total weight of the peppers and water, stir evenly, and naturally ferment for 20 days in a closed, cool, and ventilated place to obtain salted peppers. Cut the salted peppers into pieces for later use, and store all the salted pepper water for later use.

[0042] 2. Prepare sweet bean paste

[0043] (1) Select dry broad bean paste and remove impurities and moldy bean paste.

[0044] (2) Soak the selected dry broad bean pods and stir them evenly. Add water to cover the surface of the dry broad bean pods by about 10 cm. Remove the broken shells and impurities floating on the surface. Soak for 1 hour. When there is a slight white center on the cross section of the broad bean pods, remove the water to obtain the soaked broad bean pods.

[0045] (3) Mix the flour and the seed koji evenly; the amount of the seed koji added is 1.2% of the total amount of flour; the seed koji inoculated is Aspergillus oryzae CICC2339: Aspergillus nige AS3.350: Saccharomyces cerevisiae CICC32451 = 6:2:2. Mix the flour mixed with the seed koji with the broad bean petals soaked in 2(2) and stir evenly, so that the flour is evenly coated on the surface of the broad bean petals, and the ratio of flour to dry broad bean petals is 2:11, thus obtaining the inoculated broad bean petals.

[0046] (4) Loosely transfer the inoculated broad bean petals in step 2(3) into the koji bed. The material should be uniform, with a flat surface and a thickness of about 15 cm. Incubate the bed at 32°C with ventilation for 36 hours to obtain the broad bean petals koji.

[0047] (5) Crush the broad bean paste prepared in 2(4), add 35% of the total amount of the paste with the salted chili water stored in 1(2), and add 2% of the total amount of the paste with dried chili. After compacting the surface layer, cover it with 3% of the total amount of the paste and seal it with food-grade plastic. Ferment it at 35°C for 30 days to obtain sweet broad bean paste.

[0048] 3. Prepare bean paste

[0049] (1) The sweet bean paste obtained in step 2(5) and the salted chili pieces obtained in step 1(2) are placed in a fermentation tank respectively, and mixed and stirred evenly. The ratio of the sweet bean paste to the salted chili pieces is 3:11. At the same time, Saccharomyces cerevisiae CICC32451 is inoculated. The inoculation amount of the brewer's yeast is 2% of the whole system. Thus, bean paste mash is obtained, and then the bean paste is fermented. The whole bean paste fermentation is carried out in the fermentation tank.

[0050] (2) The fermentation of bean paste in 3(1) is divided into three stages. The first stage is the early stage, which lasts for about 20 days, the fermentation temperature is 35°C, and stirring is performed twice a day, each time for 3 minutes. The second stage is the mid-term stage, which lasts for 30 days, the fermentation temperature is 30°C, and stirring is performed once a day, each time for 3 minutes. On the first day of the mid-term fermentation process, the salted chili pieces obtained in 1(2) are added, and the addition amount is 1% of the whole system. The salted chili pieces obtained in 1(2) are added every 10 days thereafter. The third stage is the late fermentation stage. On the first day of the late fermentation development, 0.5% of Lactobacillus helveticus CGMCC No. 25010 of the whole system is added, and on the first day of the late fermentation, 1% of dried chili of the whole system is added. The late fermentation time is 40 days, the fermentation temperature is 30-32°C, and stirring can be adopted every other day, each time for 3 minutes. The low-salt fermented bean paste product is obtained.

[0051] Example 2

[0052] 1. Prepare salted peppers:

[0053] (1) Take mature fresh Erjingtiao peppers, trim the Erjingtiao peppers and keep the stems, wash them clean or dry them in the air, leaving no moisture on the surface. Take mature fresh millet peppers and pre-treat them in the same way as above.

[0054] (2) Weigh the processed Erjingtiao and Xiaomi Chili in a ratio of 1:1; soak them in 70°C warm water that is 6 times the total weight of the peppers, add 23% of edible salt, 6% of 52° liquor, and 3% of white sugar based on the total weight of the peppers and water, stir evenly, and naturally ferment for 25 days in a closed, cool, and ventilated place to obtain salted peppers, cut the salted peppers into pieces for later use, and store the salted pepper water for later use.

[0055] 2. Prepare sweet bean paste

[0056] (1) Select dry broad bean paste and remove impurities and moldy bean paste.

[0057] (2) Soak the selected dry broad bean pods and stir them evenly. Add water to cover the surface of the dry broad bean pods by about 10 cm. Remove the broken shells and impurities floating on the surface. Soak for 2 hours. When there is a slight white center on the cross section of the broad bean pods, remove the water to obtain the soaked broad bean pods.

[0058] (3) Mix the flour and the seed koji evenly; the amount of the seed koji added is 2.5% of the total amount of flour; the seed koji inoculated is Aspergillus oryzae CICC2339: Aspergillus nige AS3.350: Saccharomyces cerevisiae CICC32451 = 8:1:1. Mix the flour mixed with the seed koji with the broad bean petals soaked in 2(2) and stir evenly, so that the flour is evenly coated on the surface of the broad bean petals, and the ratio of flour to dry broad bean petals is 3:14, so as to obtain the inoculated broad bean petals.

[0059] (4) Loosely transfer the inoculated broad bean petals in step 2(3) into the koji bed. The material should be uniform, with a flat surface and a thickness of about 20 cm. Incubate the bed at 34°C with ventilation for 42 hours to obtain the broad bean petals koji.

[0060] (5) Crush the broad bean koji prepared in 2(4), add 40% of the salted chili water stored in 1(2) to the koji, and add 2.5% of the total amount of dried chili to the koji. After compacting the surface layer, cover it with 3.5% of the total amount of koji and seal it with food-grade plastic. Ferment it at 45°C for 45 days to obtain sweet broad bean koji.

[0061] 3. Prepare bean paste

[0062] (1) The sweet bean paste obtained in step 2(5) and the salted chili pieces obtained in step 1(2) are placed in a fermentation tank respectively, and mixed and stirred evenly. The ratio of the sweet bean paste to the salted chili pieces is 4:11. At the same time, Saccharomyces cerevisiae CICC32451 is inoculated. The inoculation amount of the brewer's yeast is 3.5% of the whole system. Thus, bean paste mash is obtained, and then the bean paste is fermented. The whole bean paste fermentation is carried out in the fermentation tank.

[0063] (2) The fermentation of the bean paste in 3(1) is divided into three stages. The first stage is the early stage, which lasts for about 25 days, the fermentation temperature is 37°C, and stirring is performed twice a day, each time for 4 minutes. The second stage is the mid-term stage, which lasts for 35 days, the fermentation temperature is 33°C, and stirring is performed once a day, each time for 4 minutes. On the first day of the mid-term fermentation process, the salted chili pieces obtained in 1(2) are added, and the addition amount is 2% of the whole system. Thereafter, the salted chili pieces obtained in 1(2) are added every 10 days. The third stage is the late fermentation stage. On the first day of the late fermentation development, 1% of Lactobacillus helveticus CGMCC No.25010 of the whole system is added, and on the first day of the late fermentation, 1.5% of dried chili of the whole system is added. The late fermentation time is 50 days, the fermentation temperature is 31°C, and stirring can be adopted every other day, each time for min. The low-salt fermented bean paste product is obtained.

[0064] Example 3

[0065] 1. Prepare salted peppers:

[0066] (1) Take mature fresh Erjingtiao peppers, trim the Erjingtiao peppers and keep the stems, wash them clean or dry them in the air, leaving no moisture on the surface. Take mature fresh millet peppers and pre-treat them in the same way as above.

[0067] (2) Weigh the processed Erjingtiao and Xiaomi Chili in a ratio of 1:1; soak them in 80°C warm water that is 8 times the total weight of the peppers, add 25% of edible salt, 8% of 52° liquor, and 5% of white sugar based on the total weight of the peppers and water, stir evenly, and naturally ferment for 30 days in a closed, cool, and ventilated place to obtain salted peppers, cut the salted peppers into pieces for later use, and store the salted pepper water for later use.

[0068] 2. Prepare sweet bean paste

[0069] (1) Select dry broad bean paste and remove impurities and moldy bean paste.

[0070] (2) Soak the selected dry broad bean pods and stir them evenly. Add water to cover the surface of the dry broad bean pods by about 10 cm. Remove the broken shells and impurities floating on the surface. Soak for 2.5 hours. When there is a slight white center on the cross section of the broad bean pods, remove the water to obtain the soaked broad bean pods.

[0071] (3) Mix the flour and the seed koji evenly; the amount of the seed koji added is 3.5% of the total amount of flour; the seed koji inoculated is Aspergillus oryzae CICC2339: Aspergillus nige AS3.350: Saccharomyces cerevisiae CICC32451 = 7:1:2. Mix the flour mixed with the seed koji and the broad bean petals soaked in 2(2) and stir evenly, so that the flour is evenly coated on the surface of the broad bean petals, and the ratio of flour to dry broad bean petals is 4:15, so as to obtain the inoculated broad bean petals.

[0072] (4) Loosely transfer the inoculated broad bean petals in step 2(3) into the koji bed. The material should be uniform, with a flat surface and a thickness of about 25 cm. Incubate the bed at 36°C with ventilation for 48 hours to obtain the broad bean petals koji.

[0073] (5) Crush the broad bean koji prepared in 2(4), add 45% of the total amount of the koji with the salted chili water stored in 1(2), and add 3% of the total amount of the koji with dried chili. After compacting the surface layer, cover it with 4% of the total amount of the koji and seal it with food-grade plastic. Ferment it at 55°C for 60 days to obtain sweet broad bean koji.

[0074] 3. Prepare bean paste

[0075] (1) The sweet bean paste obtained in step 2(5) and the salted chili pieces obtained in step 1(2) are placed in a fermentation tank respectively, and mixed and stirred evenly. The ratio of the sweet bean paste to the salted chili pieces is 5:14. At the same time, Saccharomyces cerevisiae CICC32451 is inoculated. The inoculation amount of Saccharomyces cerevisiae is 5% of the whole system. Thus, bean paste mash is obtained, and then the bean paste is fermented. The whole bean paste fermentation is carried out in the fermentation tank.

[0076] (2) The fermentation of bean paste in 3(1) is divided into three stages. The first stage is the early stage, which lasts for about 30 days, the fermentation temperature is 38°C, and stirring is performed twice a day, each time for 5 minutes. The second stage is the mid-term stage, which lasts for 40 days, the fermentation temperature is 35°C, and stirring is performed once a day, each time for 5 minutes. On the first day of the mid-term fermentation process, the salted chili pieces obtained in 1(2) are added, and the addition amount is 3% of the whole system. The salted chili pieces obtained in 1(2) are added every 10 days thereafter. The third stage is the late fermentation stage. On the first day of the late fermentation development, 1.5% of Lactobacillus helveticus CGMCC No.25010 of the whole system is added, and on the first day of the late fermentation, 2% of dried chili of the whole system is added. The late fermentation time is 60 days, the fermentation temperature is 32°C, and stirring can be adopted every other day, each time for 5 minutes. The low-salt fermented bean paste product is obtained.

[0077] Example 4

[0078] 1. Prepare salted peppers:

[0079] (1) Take mature fresh Erjingtiao peppers, trim the Erjingtiao peppers and keep the stems, wash them clean or dry them in the air, leaving no moisture on the surface. Take mature fresh millet peppers and pre-treat them in the same way as above.

[0080] (2) Weigh the processed Erjingtiao and Xiaomi Chili in a ratio of 1:1; soak them in 70°C warm water 8 times the total weight of the peppers, add 25% of edible salt, 7% of 52° liquor, and 4% of white sugar based on the total weight of the peppers and water, stir evenly, and naturally ferment for 30 days in a closed, cool, and ventilated place to obtain salted peppers, cut the salted peppers into pieces for later use, and store the salted pepper water for later use.

[0081] 2. Prepare sweet bean paste

[0082] (1) Select dry broad bean paste and remove impurities and moldy bean paste.

[0083] (2) Soak the selected dry broad bean pods and stir them evenly. Add water to cover the surface of the dry broad bean pods by about 10 cm. Remove the broken shells and impurities floating on the surface. Soak for 2 hours. When there is a slight white center on the cross section of the broad bean pods, remove the water to obtain the soaked broad bean pods.

[0084] (3) Mix the flour and the seed koji evenly; the amount of the seed koji added is 2% of the total amount of the flour; the seed koji inoculated is Aspergillus oryzae CICC2339: Aspergillus nige AS3.350: Saccharomyces cerevisiae CICC32451 = 7:2:1. Mix the flour mixed with the seed koji with the broad bean petals soaked in 2(2) and stir evenly, so that the flour is evenly coated on the surface of the broad bean petals, and the ratio of flour to dry broad bean petals is 5:14, thus obtaining the inoculated broad bean petals.

[0085] (4) Loosely transfer the inoculated broad bean petals in step 2(3) into the koji bed. The material should be uniform, with a flat surface and a thickness of about 20 cm. Incubate the bed at 36°C with ventilation for 48 hours to obtain the broad bean petals koji.

[0086] (5) Crush the broad bean koji prepared in 2(4), add 40% of the salted chili water stored in 1(2) to the koji, and add 2.5% of the dry chili to the koji. After compacting the surface layer, cover it with 4% of the koji, and seal it with food-grade plastic. Ferment it at 340°C for 60 days to obtain sweet broad bean koji.

[0087] 3. Prepare bean paste

[0088] (1) The sweet bean paste obtained in step 2(5) and the salted chili pieces obtained in step 1(2) are placed in a fermentation tank respectively, and mixed and stirred evenly. The ratio of the sweet bean paste to the salted chili pieces is 3:8. At the same time, Saccharomyces cerevisiae CICC32451 is added. The inoculation amount of the brewer's yeast is 4% of the whole system. Thus, bean paste mash is obtained, and then the bean paste is fermented. The whole bean paste fermentation is carried out in the fermentation tank.

[0089] (2) The fermentation of the bean paste in 3(1) is divided into three stages. The first stage is the early stage, which lasts for about 30 days, the fermentation temperature is 36°C, and stirring is performed twice a day, each time for 3 minutes. The second stage is the mid-term stage, which lasts for 40 days, the fermentation temperature is 34°C, and stirring is performed once a day, each time for 3 minutes. On the first day of the mid-term fermentation process, the salted chili pieces obtained in 1(2) are added, and the addition amount is 2% of the whole system. The salted chili pieces obtained in 1(2) are added every 10 days thereafter. The third stage is the late fermentation stage. On the first day of the late fermentation development, 1.2% of Lactobacillus helveticus CGMCC No. 25010 of the whole system is added, and on the first day of the late fermentation, 2% of dried chili of the whole system is added. The late fermentation time is 60 days, the fermentation temperature is 32°C, and stirring can be adopted every other day, each time for 3 minutes. The finished product of low-salt fermented bean paste is obtained.

[0090] Example 5

[0091] 1. Prepare salted peppers:

[0092] (1) Take dried Erjingtiao pepper, rehydrate it with 3 times the amount of water, then wash and dry it, and there should be no water droplets on the surface. Take dried Xiaomi La pepper and pretreat it in the same way as above.

[0093] (2) Weigh the processed Erjingtiao and Xiaomi Chili in a ratio of 1:1; soak them in 70°C warm water that is 6 times the total weight of the peppers, add 23% of edible salt, 6% of 52° liquor, and 3% of white sugar based on the total weight of the peppers and water, stir evenly, and naturally ferment for 25 days in a closed, cool, and ventilated place to obtain salted peppers, cut the salted peppers into pieces for later use, and store the salted pepper water for later use.

[0094] 2. Prepare sweet bean paste

[0095] (1) Select dry broad bean paste and remove impurities and moldy bean paste.

[0096] (2) Soak the selected dry broad bean pods and stir them evenly. Add water to cover the surface of the dry broad bean pods by about 10 cm. Remove the broken shells and impurities floating on the surface. Soak for 2 hours. When there is a slight white center on the cross section of the broad bean pods, remove the water to obtain the soaked broad bean pods.

[0097] (3) Mix the flour and the seed koji evenly; the amount of the seed koji added is 2.5% of the total amount of flour; the seed koji inoculated is Aspergillus oryzae CICC2339: Aspergillus nige AS3.350: Saccharomyces cerevisiae CICC32451 = 7:1:2. Mix the flour mixed with the seed koji with the broad bean petals soaked in 2(2) and stir evenly, so that the flour is evenly coated on the surface of the broad bean petals, and the ratio of flour to dry broad bean petals is 3:14, thus obtaining the inoculated broad bean petals.

[0098] (4) Loosely transfer the inoculated broad bean petals in step 2(3) into the koji bed. The material should be uniform, with a flat surface and a thickness of about 20 cm. Incubate the bed at 34°C with ventilation for 42 hours to obtain the broad bean petals koji.

[0099] (5) Crush the broad bean koji prepared in 2(4), add 40% of the salted chili water stored in 1(2) to the koji, and add 2.5% of the total amount of dried chili to the koji. After compacting the surface layer, cover it with 3.5% of the total amount of koji and seal it with food-grade plastic. Ferment it at 45°C for 45 days to obtain sweet broad bean koji.

[0100] 3. Prepare bean paste

[0101] (1) The sweet bean paste obtained in step 2(5) and the salted chili pieces obtained in step 1(2) are placed in a fermentation tank respectively, and mixed and stirred evenly. The ratio of the sweet bean paste to the salted chili pieces is 4:11. At the same time, Saccharomyces cerevisiae CICC32451 is inoculated. The inoculation amount of the brewer's yeast is 3.5% of the whole system. Thus, bean paste mash is obtained, and then the bean paste is fermented. The whole bean paste fermentation is carried out in the fermentation tank.

[0102] (2) The fermentation of bean paste in 3(1) is divided into three stages. The first stage is the early stage, which lasts for about 25 days, the fermentation temperature is 37°C, and stirring is performed twice a day, each time for 4 minutes. The second stage is the middle stage, which lasts for 35 days, the fermentation temperature is 33°C, and stirring is performed once a day, each time for 4 minutes. On the first day of the middle fermentation process, the salted chili pieces obtained in 1(2) are added, and the addition amount is 2% of the whole system. Thereafter, the salted chili pieces obtained in 1(2) are added every 10 days. The third stage is the late fermentation stage. On the first day of the late fermentation development, 1% of Lactobacillus helveticus CGMCC No.25010 of the whole system is added, and on the first day of the late fermentation, 2% of dried chili of the whole system is added. The late fermentation time is 50 days, the fermentation temperature is 31°C, and stirring can be adopted every other day, each time for 4 minutes. The low-salt fermented bean paste product is obtained.

[0103] Example 6: Fermentation tank structure

[0104] Please refer to Figure 1 A fermentation tank structure matched with a method for preparing a low-salt bean paste comprises a motor (10), a ground fixing device (20), a fermentation tank body (30), a stirring component (40), and a detachable insulation layer (50), wherein the fermentation tank body (30) is mounted on the ground fixing device (20), and the stirring component (40) is rotatably mounted in the fermentation tank body (30).

[0105] The fermentation tank body (30) is provided with a filling port, the fermentation tank body (30) is made of stainless steel, a graphene layer is provided inside the fermentation tank body (30), and the fermentation tank body (30) is transversely arranged in a parallel direction. A control panel is provided on the fermentation tank body (30), and the control panel is provided with a temperature control key, a temperature display, a stirring control key, and a stirring control display.

[0106] The stirring assembly (40) comprises a transmission shaft (41) and a stirring paddle disposed on the transmission shaft (41), wherein the stirring paddle comprises a straight stirring paddle (42) and a spiral stirring paddle (43), and the straight stirring paddle (42) and the spiral stirring paddle (43) are disposed on the transmission shaft (41). Specifically, the spiral stirring paddle (43) is disposed in the middle of the transmission shaft (41), and the straight stirring paddle (42) is disposed on both sides of the spiral stirring paddle (43).

[0107] The detachable heat-insulating layer (50) is detachably mounted on the outer side of the fermentation tank body (30), and a plurality of heating tubes (51) are arranged in the detachable heat-insulating layer (50). A detachable food-grade transmission pipeline is arranged in the filling port (60).

[0108] (II) Comparative Example

[0109] Comparative Example 1

[0110] 1. Prepare salted peppers:

[0111] (1) Take mature fresh Erjingtiao peppers, trim the Erjingtiao peppers and keep the stems, wash them clean or dry them in the air, leaving no moisture on the surface. Take mature fresh millet peppers and pre-treat them in the same way as above.

[0112] (2) Weigh the processed Erjingtiao and Xiaomi La in a ratio of 1:1; soak the peppers in 50°C warm water 3 times the total weight of the peppers, add 19% edible salt, 4% 52° liquor, and 1% white sugar based on the total weight of the peppers and water, stir evenly, and naturally ferment for 20 days in a closed, cool, and ventilated place to obtain salted peppers, cut the salted peppers into pieces for later use, and store the salted pepper water for later use.

[0113] 2. Prepare sweet bean paste

[0114] (1) Select dry broad bean paste and remove impurities and moldy bean paste.

[0115] (2) Soak the selected dry broad bean pods and stir them evenly. Add water to cover the surface of the dry broad bean pods by about 10 cm. Remove the broken shells and impurities floating on the surface. Soak for 1 hour. When there is a slight white center on the cross section of the broad bean pods, remove the water to obtain the soaked broad bean pods.

[0116] (3) Mix the flour and the seed koji evenly; the amount of the seed koji added is 1.1% of the total amount of flour; the seed koji inoculated is Aspergillus oryzae CICC2339: Aspergillus nige AS3.350: Saccharomyces cerevisiae CICC32451 = 5:2.5:2.5. Mix the flour mixed with the seed koji with the broad bean petals soaked in 2(2) and stir evenly, so that the flour is evenly coated on the surface of the broad bean petals, and the ratio of flour to dry broad bean petals is 1:8, thus obtaining the inoculated broad bean petals.

[0117] (4) Loosely transfer the inoculated broad bean petals in step 2(3) into the koji bed. The material should be uniform, with a flat surface and a thickness of about 15 cm. Incubate the bed at 32°C with ventilation for 36 hours to obtain the broad bean petals koji.

[0118] (5) Crush the broad bean paste prepared in 2(4), add 34% of the total amount of the paste from the salted chili water stored in 1(2), and add 1% of the total amount of the paste. After compacting the surface layer, cover it with 2% of the total amount of the paste and seal it with food-grade plastic. Ferment it at 35°C for 30 days to obtain sweet broad bean paste.

[0119] 3. Prepare bean paste

[0120] (1) The sweet bean paste obtained in step 2(5) and the salted chili pieces obtained in step 1(2) are placed in a fermentation tank respectively, and mixed and stirred evenly. The ratio of the sweet bean paste to the salted chili pieces is 2:7. At the same time, Saccharomyces cerevisiae CICC32451 is inoculated. The inoculation amount of the brewer's yeast is 1% of the whole system. Thus, bean paste mash is obtained, and then the bean paste is fermented. The whole bean paste fermentation is carried out in the fermentation tank.

[0121] (2) The fermentation of the bean paste in 3(1) is divided into three stages. The first stage is the early stage, which lasts for about 20 days, the fermentation temperature is 35°C, and stirring is performed twice a day, each time for 3 minutes. The second stage is the mid-term stage, which lasts for 30 days, the fermentation temperature is 30°C, and stirring is performed once a day, each time for 3 minutes. On the first day of the mid-term fermentation process, the salted chili pieces obtained in 1(2) are added, and the addition amount is 0.5% of the whole system. The salted chili pieces obtained in 1(2) are added every 10 days thereafter. The third stage is the late fermentation stage. On the first day of the late fermentation development, 0.4% of Lactobacillus helveticus CGMCC No.25010 of the whole system is added, and on the first day of the late fermentation, 0.5% of dried chili of the whole system is added. The late fermentation time is 40 days, the fermentation temperature is 30°C, and stirring can be adopted every other day, each time for 3 minutes. The low-salt fermented bean paste product is obtained.

[0122] Comparative Example 2

[0123] Based on Comparative Example 1, the difference from Comparative Example 1 is that

[0124] 1. The seed koji added during step 2(3) lacks brewer's yeast;

[0125] 2. No dried chili pepper was added during step 2 (5);

[0126] 3. Saccharomyces cerevisiae was not introduced during step 3(1);

[0127] 4. In step 3(2), no salted chili pieces, no Lactobacillus helveticus, and no dried chili were added.

[0128] Comparative Example 3

[0129] 1. Prepare salted peppers:

[0130] (1) Take mature fresh Erjingtiao peppers, trim the Erjingtiao peppers and keep the stems, wash them clean or dry them in the air, leaving no moisture on the surface. Take mature fresh millet peppers and pre-treat them in the same way as above.

[0131] (2) Weigh the processed Erjingtiao and Xiaomi Chili in a ratio of 1:1; soak them in 70°C warm water that is 9 times the total weight of the peppers, add 26% of edible salt, 9% of 52° liquor, and 6% of white sugar based on the total weight of the peppers and water, stir evenly, and naturally ferment for 30 days in a closed, cool, and ventilated place to obtain salted peppers, cut the salted peppers into pieces for later use, and store the salted pepper water for later use.

[0132] 2. Prepare sweet bean paste

[0133] (1) Select dry broad bean paste and remove impurities and moldy bean paste.

[0134] (2) Soak the selected dry broad bean pods and stir them evenly. Add water to cover the surface of the dry broad bean pods by about 10 cm. Remove the broken shells and impurities floating on the surface. Soak for 2.5 hours. When there is a slight white center on the cross section of the broad bean pods, remove the water to obtain the soaked broad bean pods.

[0135] (3) Mix the flour and the seed koji evenly; the amount of the seed koji added is 4% of the total amount of the flour; the seed koji inoculated is Aspergillus oryzae CICC2339: Aspergillus nige AS3.350: Saccharomyces cerevisiae CICC32451 = 5:2.5:2.5. Mix the flour mixed with the seed koji with the broad bean petals soaked in 2(2) and stir evenly, so that the flour is evenly coated on the surface of the broad bean petals, and the ratio of flour to dry broad bean petals is 1:16, thus obtaining the inoculated broad bean petals.

[0136] (4) Loosely transfer the inoculated broad bean petals in step 2(3) into the koji bed. The material should be uniform, with a flat surface and a thickness of about 25 cm. Incubate the bed at 36°C with ventilation for 48 hours to obtain the broad bean petals koji.

[0137] (5) Crush the broad bean koji prepared in 2(4), add 46% of the salted chili water stored in 1(2) to the koji, and add 4% of the dry chili to the koji. After compacting the surface layer, cover it with 5% of the total amount of koji and seal it with food-grade plastic. Ferment it at 55°C for 60 days to obtain sweet broad bean koji.

[0138] 3. Prepare bean paste

[0139] (1) The sweet bean paste obtained in step 2(5) and the salted chili pieces obtained in step 1(2) are placed in a fermentation tank respectively, and mixed and stirred evenly. The ratio of the sweet bean paste to the salted chili pieces is 6:15. At the same time, Saccharomyces cerevisiae CICC32451 is introduced. The inoculation amount of the brewer's yeast is 6% of the whole system. Thus, bean paste mash is obtained, and then the bean paste is fermented. The whole bean paste fermentation is carried out in the fermentation tank.

[0140] (2) The fermentation of bean paste in 3(1) is divided into three stages. The first stage is the early stage, which lasts for about 30 days, the fermentation temperature is 38°C, and stirring is performed twice a day, each time for 5 minutes. The second stage is the middle stage, which lasts for 40 days, the fermentation temperature is 35°C, and stirring is performed once a day, each time for 5 minutes. On the first day of the middle fermentation process, the salted chili pieces obtained in 1(2) are added, and the addition amount is 4% of the whole system. The salted chili pieces obtained in 1(2) are added every 10 days thereafter. The third stage is the late fermentation stage. On the first day of the late fermentation development, 2% of Lactobacillus helveticus CGMCC No.25010 of the whole system is added, and on the first day of the late fermentation, 3% of dried chili of the whole system is added. The late fermentation time is 60 days, the fermentation temperature is 32°C, and stirring can be adopted every other day, each time for 5 minutes. Low-salt fermented bean paste is obtained.

[0141] Comparative Example 4

[0142] Based on Example 1, the difference from Example 1 is that

[0143] 1. In step 3 (1), the sweet bean paste and the salted chili pieces are placed in common fermentation tanks respectively;

[0144] 2. There is no graphene material on the inner wall of ordinary fermentation tanks;

[0145] 3. There is no built-in detachable food-grade delivery pipe at the filling port of the ordinary fermentation tank.

[0146] (III) Experimental Examples

[0147] Finished product testing method:

[0148] 1. Sensory analysis: 30 sensory evaluators from a professional sensory evaluation team were selected to perform sensory analysis and score the samples obtained from Examples 1-5 and Comparative Examples 1-4 of the present invention according to the following table. The results were calculated based on the average of the scoring results of the 30 sensory evaluators.

[0149]

[0150]

[0151] 2. The moisture content of Examples 1-5 and Comparative Examples 1-4 was tested according to the direct drying method in GB 5009.3-2003.

[0152] 3. The salt, amino acid nitrogen, total acid and aflatoxin B1 of Examples 1-5 and Comparative Examples 1-4 were tested according to the method specified in GB / T 5009.40.

[0153] 4. The coliform bacteria and pathogenic bacteria (Salmonella, Staphylococcus aureus, Shigella) of Examples 1-5 and Comparative Examples 1-4 were detected according to the method specified in GB / T 4789.22.

[0154] 5. The amino acid content of Examples 1-5 and Comparative Examples 1-4 was tested in accordance with GB 5009.124-2016 “Determination of Amino Acids in Foods”.

[0155] 6. Volatile flavor component detection: The volatile flavor component of Examples 1-5 and Comparative Examples 1-4 was detected according to the following method.

[0156] (1) Extraction conditions: 2 g of bean paste sample was placed in a 15 mL sample bottle, sealed, and the magnetic stirring device was set at 120 °C and a rotation speed of 1.5 r / s for 600 s. Then, the extraction head (75 μm) was inserted into the sample bottle for extraction for 3 min, and then inserted into the GC-MS injection port for desorption for 600 s.

[0157] (2) GC conditions: injection port temperature 250°C; chromatographic column Elite-5MS (30 mm × 0.25 mm × 0.25 um); temperature program: starting temperature 40°C, hold for 1 min, increase to 170°C at 5°C / min, hold for 1 min, then increase to 250°C at 15°C / min, hold for 1 min; carrier gas (helium 99.9999%), flow rate 1 ml / min, split ratio 5:1.

[0158] (3) MS conditions: EI ion source, electron impact energy 70 eV, ion source temperature 230 °C; full scan; mass scan range 35-400 m / z; scan 66 s; standard tuning file.

[0159] Test results:

[0160] 1. The sensory evaluation results are as follows:

[0161] Table 1: Sensory evaluation results of samples of Examples 1-5 and Comparative Examples 1-4

[0162]

[0163] From the sensory evaluation data of Examples 1-5 and Comparative Examples 1-3, it can be seen that: (1) Examples 1-5 are significantly better than Comparative Examples 1-3 in terms of color, smell, tissue morphology, taste and total score, indicating that the bean paste products prepared by the present invention are better in terms of aroma, taste and state, and have good color, aroma and taste. (2) The score levels of Examples 1-4 are at the same level, but have a slight upward trend, indicating that the adjustment of the proportion of strains during the koji making process of sweet bean paste, especially the increase in the proportion of brewer's yeast, has a positive effect on the sensory organs of the final product; at the same time, the addition of dry chili peppers during the koji making process of sweet bean paste also has a positive effect on the sensory organs of the product; the addition of salted chili block substrates during the fermentation of bean paste, the increase in the access amount of Swiss lactic acid bacteria, and the increase in the amount of dry chili peppers all have a positive effect on the final product, making the aroma, taste and tissue state of the final product better. (3) Among the comparative examples 1-3, the sensory perception of the product obtained in comparative example 2 is the worst, which also shows that the sweet bean paste koji making process does not include the addition of brewer's yeast, the sweet bean paste fermentation does not include the addition of dried chili peppers, the fermentation process of bean paste does not include the addition of brewer's yeast and Swiss lactobacillus, the addition of salted chili pieces, and the addition of dried chili peppers, which has a great impact on the sensory perception of the final product, seriously affecting the aroma, color, taste and texture of the bean paste, resulting in the worst sensory perception of the final product of Example 2. (4) The sensory data of comparative examples 1 and 3 are better than those of comparative example 2, which again shows that the addition of brewer's yeast and dried chili peppers in the sweet bean paste fermentation process, the addition of brewer's yeast and Swiss lactobacillus in the fermentation process of bean paste, and the addition of fermentation substrates salted chili peppers and dried chili peppers have a certain positive promoting effect on the final product in this patent. However, since the addition range of comparative examples 1 and 3 is not within the scope of the present invention, the sensory perception of the final product obtained is significantly different from that of the product obtained in Examples 1-5 of the present invention, which also shows the superiority of the process range of the present invention. (5) The sensory data of comparative example 4 is significantly better than that of comparative examples 1-3, which once again proves that the addition of brewer's yeast and dried chili in the sweet bean paste fermentation process of the present invention, as well as the addition of brewer's yeast and Lactobacillus helveticus in the fermentation process of bean paste, and the addition of fermentation substrates salted chili and dried chili have a positive promoting effect on the final product, and the addition range within the patent of the present invention is better; the sensory data of Example 1 is significantly better than that of comparative example 4, indicating that the graphene material of the inner wall of the fermentation tank device in the present invention and the detachable food-grade delivery pipe built into the filling port can effectively improve the reaction rate and effectively and evenly disperse the added substrate and enzyme, which has a good promoting effect on the fermentation, so that the sensory indicators of the final product are better.

[0164] 2. The results of physical and chemical indicators and microbiological indicators are as follows:

[0165] Table 2: Physical and chemical indexes and microbiological indexes of samples of Examples 1-5 and Comparative Examples 1-4

[0166]

[0167] From the data of moisture index in Table 2, it can be seen that: (1) the moisture content of Examples 1-5 is lower than that of Comparative Examples 1-3, which is about 15-30% lower. It can be seen that the process of the present invention has a better control over the moisture content of the final product; (2) The moisture data of Examples 1-5 show a downward trend, which is the opposite trend to the increase of the dry chili content in the two links of adding dry chili in Examples 1-5, indicating that the addition of dry chili can well balance the moisture content and reduce the moisture content in the total material and the final product. (3) The moderate moisture content can also be intuitively reflected in the tissue morphology in the senses. The data change trend of the moisture content is opposite to the change trend of the tissue morphology in the sensory analysis, which can just illustrate this point.

[0168] From the salt content data in Table 2, it can be seen that: (1) the salt content of the samples prepared in Examples 1-5 is between 6% and 8%, which is about 5% lower than the salt content of about 18% to 20% of the bean paste on the market, indicating that the process of the present invention can prepare a low-salt bean paste product; (2) although the salt content of Comparative Examples 1-3 is significantly higher than the salt content of Examples 1-5, it is also significantly lower than the salt content of 18% to 20% of the bean paste on the market, further indicating that the overall process of the present invention has a method for reducing the salt content of bean paste, and the effect is significant, but the salt content of Examples 1-5 is significantly lower than the salt content of Comparative Examples 1-3, indicating that the process parameter range of the present invention can well ensure the low-salt effect of the bean paste product.

[0169] It can be seen from the amino acid nitrogen data in Table 2 that: (1) the amino acid nitrogen content of the samples prepared in Examples 1-5 is significantly higher than that of the samples prepared in Comparative Examples 1-3, indicating that the process conditions of the present invention can well increase the amino acid nitrogen content in the final product; (2) the amino acid nitrogen content in Examples 1-5 shows an obvious upward trend, which is consistent with the upward trend of the access amount of brewer's yeast, and also confirms that the access of brewer's yeast can secrete some proteases during the metabolic process of the entire system, which synergizes with the proteases during koji making to increase the amino acid nitrogen content; (3) the amino acid nitrogen content of Comparative Example 2 is the lowest among all the embodiments and comparative examples, because there is no access to brewer's yeast in Comparative Example 2.

[0170] It can be seen from the total acid data in Table 2 that the total acid content of the samples prepared in Examples 1-5 is significantly lower than the total acid content in the samples prepared in Comparative Examples 1-3, indicating that the process range of the present invention can well ensure the total acid range in the final product and will not be excessive to cause rancidity of the final product.

[0171] From the data of aflatoxin B1 in Table 2, it can be seen that: (1) Aflatoxin B1 was not detected in the final products prepared in Examples 1-5, indicating that the process of the present invention can well ensure the quality and safety of the bean paste products, and it can also be shown that the addition of brewer's yeast has a certain antibacterial effect; (2) The aflatoxin B1 in Comparative Example 1 is half that in Comparative Example 2, which further shows that brewer's yeast has a certain antibacterial effect; (3) Both Comparative Examples 1 and 3 contain a certain amount of aflatoxin B1, indicating that the process and process parameter range of the present invention can ensure the quality and safety of the products, and the parameters outside the range have certain quality risks.

[0172] From the data of coliform bacteria in Table 2, it can be seen that: (1) no coliform bacteria were detected in the final products prepared in Examples 1-5, indicating that the process of the present invention can well ensure the quality and safety of the bean paste products, and that the addition of brewer's yeast has a certain antibacterial effect; (2) the number of coliform bacteria in Comparative Example 1 is 40% less than that in Comparative Example 2, which further indicates that brewer's yeast has a certain antibacterial effect;

[0173] It can be seen from the pathogenic bacteria data in Table 2 that no pathogenic bacteria were detected in all the embodiments and comparative examples, which further illustrates that the process of the present invention can ensure the quality and safety of the bean paste product.

[0174] It can be seen from the fact that the data of Example 1 in Table 2 are better than those of Comparative Example 4 that the graphene material added to the inner wall of the device of the present invention and the detachable food-grade delivery pipe built into the filling port have a positive promoting effect on the fermentation process.

[0175] 3. The amino acid content results are as follows:

[0176] Table 3: Amino acid content results of samples of Examples 1-5 and Comparative Examples 1-4

[0177]

[0178]

[0179] From the amino acid content data in Table 3, it can be seen that: (1) the umami amino acid content and total amino acid content in Examples 1-5 are much higher than those in Comparative Examples 1-3, and there is a significant difference, indicating that the process and process conditions of the present invention have a positive promoting effect on the amino acid content of the final product of bean paste. The role of different enzyme systems of Aspergillus oryzae, Aspergillus niger, Saccharomyces cerevisiae and lactic acid bacteria in the metabolism of the whole system ensures that the utilization rate of broad beans by microorganisms is high, thereby ensuring that the amino acid content of the product is high, making the product taste richer; (2) The umami amino acid content and total amino acid content of Comparative Example 1 are also higher than those of Comparative Example 2 in a low range, indicating that the access of Saccharomyces cerevisiae can also secrete some proteases in the metabolic process of the whole system, and synergize with the proteases during koji making to increase the content of amino acid nitrogen. (3) The umami amino acid content and total amino acid content in Example 1 are significantly better than those in Comparative Example 4, indicating that the graphene material added to the inner wall of the device of the present invention and the detachable food-grade conveying pipe built into the filling port have a positive promoting effect on the fermentation.

[0180] 4. The content of volatile flavor substances is as follows:

[0181] Table 4: Volatile flavor component content results of samples of Examples 1-5 and Comparative Examples 1-4

[0182]

[0183] From the data of volatile flavor component content in Table 4, it can be seen that: (1) The volatile flavor content in Examples 1-5 is much higher than that in Examples 1-3, indicating that within the process and process parameters of the present invention, the role of microorganisms and enzyme systems is maximized, and more flavor substances can be produced, thereby improving the flavor of the final product. (2) The volatile flavor content in Example 1 is significantly better than that in Comparative Example 4, indicating that the graphene material added to the inner wall of the device of the present invention and the detachable food-grade delivery pipe built into the filling port have a positive effect on the fermentation process.

[0184] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing low-salt bean paste, characterized in that: The following steps are involved: S1 Preparation of salted peppers: S11: taking mature Erjingtiao fresh or dried peppers, trimming the Erjingtiao fresh peppers and leaving the stalks, washing or drying them, and removing moisture from the surface; and rehydrating the Erjingtiao dried peppers by adding 3 to 8 times of water; taking mature Xiaoxiaola fresh or dried peppers, and pre-treating them in the same manner as above; S12: Weigh the processed Erjingtiao and Xiaojiao according to a weight ratio of 1 to 2:1, soak them in warm water of 60-80°C, which is 5 to 8 times the total mass of the peppers, and then add 20 to 25% edible salt, 5 to 8% 52° liquor, and 2 to 5% white sugar based on the total mass of the peppers and water, stir evenly, and naturally ferment in a closed, cool, and ventilated place for 20 to 30 days to obtain salted peppers, cut the salted peppers into pieces for later use, and store the salted pepper water for later use; S2 Preparation of sweet bean paste: S21: Select dry broad bean stalks, remove impurities and moldy broad bean stalks, soak the selected dry broad bean stalks in water, add water to cover the surface of the dry broad bean stalks by 10 to 15 cm, stir evenly, remove broken shells and impurities floating on the surface, soak for 1 to 2.5 hours, and remove water after a line of white core is slightly visible on the cross section of the broad bean stalks, thereby obtaining the soaked broad bean stalks; S22: mixing the flour and the seed koji uniformly, wherein the amount of the seed koji added is 1.2-3.5% of the total weight of the flour, and the seed koji is selected from any one or more of Aspergillus oryzae, Aspergillus nige, and Saccharomyces cerevisiae; further, the seed koji is composed of Aspergillus oryzae, Aspergillus nige, and Saccharomyces cerevisiae, and the mass ratio thereof is 6-8:1-2:1-2; S23: mixing the flour mixed with the seed koji and the broad bean petals soaked in S21 and stirring evenly, so that the flour is evenly coated on the surface of the broad bean petals, and the mass ratio of the flour to the dry broad bean petals is 1-5:10-15, so as to obtain the inoculated broad bean petals; S24: transferring the inoculated broad bean petals into a koji bed, so that the broad bean petals are uniform and have a flat surface, with a thickness of about 15 to 25 cm, and ventilating and koji making at 32 to 36° C. for 36 to 48 hours to obtain broad bean petals koji; S25: breaking the broad bean scallops into pieces, adding the salted chili water prepared in S12, wherein the salted chili water accounts for 35-45% of the total mass of the scallops, and adding 2-3% of the total mass of dried chili peppers, compacting the surface layer, and then covering the scallops with 3-4% of the total mass of edible salt, and sealing with food-grade plastic, and fermenting at 35-55° C. for 30-60 days to obtain sweet broad bean scallops; S3 Preparation of bean paste: S31: placing the sweet bean paste prepared in S25 and the salted chili pieces prepared in S12 in a fermentation tank, mixing and stirring them evenly, wherein the mass ratio of the sweet bean paste to the salted chili pieces is 3-5:8-14, and simultaneously inoculating Saccharomyces cerevisiae brewer's yeast, wherein the inoculation amount of the brewer's yeast is 2-5% of the total mass of the sweet bean paste and the salted chili pieces, to obtain bean paste fermented rice; S32: The fermented bean curd obtained in 31 is placed in a fermentation tank for fermentation. The fermentation is carried out in three stages. The first stage is an early stage, which lasts for about 20 to 30 days, the fermentation temperature is 35 to 38° C., and stirring is performed 1 to 3 times a day, each time for 3 to 5 minutes; the second stage is a mid-term stage, which lasts for 30 to 40 days, the fermentation temperature is 30 to 35° C., and stirring is performed 1 to 2 times a day, each time for 3 to 5 minutes. On the first day of the mid-term fermentation process, the salted chili pieces prepared in S12 are added, and the added amount is 1 to 3% of the mass of the bean curd when the early stage is completed. The same mass of salted chili pieces is added every 10 days thereafter; the third stage is a late fermentation stage, and on the first day of the late fermentation, 0.5-1.5% of the mass of the bean curd when the mid-term stage is completed is added to the Lactobacillus helveticus CGMCC No.25010, and 1-2% of the mass of the fermented bean paste when the middle stage is completed. The late fermentation time is 40-60 days, the fermentation temperature is 30-32°C, stirring 1-2 times every other day, each time for 3-5 minutes. After the fermentation is completed, low-salt fermented bean paste is obtained.

2. A fermentation tank structure for the method for preparing low-salt bean paste according to claim 1, characterized in that: The invention comprises a motor (10), a ground fixing device (20), a fermentation tank body (30), a stirring component (40), and a detachable heat-insulating layer (50), wherein the fermentation tank body (30) is mounted on the ground fixing device (20), the stirring component (40) is rotatably mounted in the fermentation tank body (30), and the motor (10) is fixedly connected to the stirring component (40) and drives the stirring component (40) to rotate; The fermentation tank body (30) is provided with a feed inlet (31) and a discharge outlet (32) respectively along the upper and lower sides; the stirring assembly (40) comprises a transmission shaft (41) and a stirring paddle arranged on the transmission shaft (41); the detachable insulation layer (50) is detachably installed on the outer side of the fermentation tank body (30); and a plurality of heating tubes (51) are arranged in the detachable insulation layer (50).

3. The fermentation tank structure according to claim 2, characterized in that: The stirring paddles include a straight stirring paddle (42) and a spiral stirring paddle (43), and the straight stirring paddle (42) and the spiral stirring paddle (43) are arranged on the transmission shaft (41).

4. The fermentation tank structure according to claim 3, characterized in that: The spiral stirring paddle (43) is arranged at the middle of the transmission shaft (41), and the straight stirring paddle (42) is arranged at both sides of the spiral stirring paddle (43).

5. The fermentation tank structure according to claim 2, characterized in that: The fermentation tank body (30) is provided with a filling port (60).

6. The fermentation tank structure according to claim 2, characterized in that: The fermentation tank body (30) is made of stainless steel, and a graphene layer is arranged inside the fermentation tank body (30).

7. The fermentation tank structure according to claim 2, characterized in that: The fermentation tank body (30) is arranged transversely along a parallel direction.

8. The fermentation tank structure according to claim 5, characterized in that: A detachable food-grade transmission pipeline is arranged in the filling port (60).

9. The fermentation tank structure according to claim 2, characterized in that: The fermentation tank body (30) is provided with a control panel, and the control panel is provided with a temperature control key, a temperature display, a stirring control key and a stirring control display.

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