Monascus-aspergillus oryzae combined fungicide and application thereof in Pixian thick broad-bean sauce

Abstract

The invention relates to the field of food processing, in particular to a monascus-aspergillus oryzae combined fungicide and application thereof in Pixian thick broad-bean sauce. A monascus and aspergillus oryzae strain co-culture method is applied in a koji making stage of traditional Pixian bean paste broad bean koji, whole-grain broad beans are fermented by aspergillus oryzae according to a traditional mode, and broken broad beans are fermented by monascus so as to improve the quality of fermented food. Compared with pure culture, co-culture of the complex microbial inoculants possibly positively affects generation of an enzyme mixture, and the defect that an enzyme system formed by a single strain is single is overcome. The thick broad-bean sauce prepared by using the combined microbial agent is obviously improved in color value, high in protease activity, and high in content of amino acid nitrogen and free amino acid.

Description

Technical Field

[0001] The invention relates to the field of food processing, and in particular to a Monascus-Aspergillus oryzae combined bacterial agent and application thereof in Pixian bean paste. Background Art

[0002] Pixian Douban is made of broad beans and peppers as the main raw materials, wheat flour and salt as auxiliary materials. Under certain salt concentration conditions, it undergoes the traditional fermentation process of "turning, sun-drying and exposing" to finally produce a fermented seasoning with a unique flavor. The preparation of broad bean koji is an important process in the production of Pixian Douban, and Aspergillus oryzae is the key microorganism in the production of broad bean koji. At present, most Pixian Douban production companies still use Shanghai Brewing 3.042 Aspergillus oryzae, which is specially used for brewing soy sauce, to produce Pixian Douban. Although soy sauce and Pixian Douban both belong to the Aspergillus oryzae fermentation system, soy sauce requires crude oil, while Pixian Douban requires sauce, and their fermentation control is different. Although Aspergillus oryzae has a high activity of hydrolase, the enzyme system is uneven, and some companies currently use sweet pepper powder to increase the color value of the product in order to make the color of Pixian Douban more ruddy. At the same time, many people may have the impression that high salt is unhealthy when they mention Pixian Douban, while Monascus has the function of esterification and flavor enhancement, and metabolizing the healthy functional ingredient-lovastatin. Therefore, a high-yield lovastatin Monascus strain was screened out, which not only improved the color value of bean curd, but also produced high-yield lovastatin, which can lower blood lipids, and provided valuable strain resources for the production of lovastatin. Therefore, screening out high-quality strains or composite bacterial agents that are more suitable for Pixian bean curd fermentation and have higher and more uniform enzyme systems and improved system color value for broad bean koji production will greatly promote the improvement of Pixian bean curd production quality and have important significance for the entire industry. Summary of the invention

[0003] In view of this, the present invention provides a Monascus-Aspergillus oryzae combined bacterial agent and its application in Pixian Douban, and a co-cultivation method of Monascus and Aspergillus oryzae species is applied in the koji making stage of traditional Pixian Douban broad bean koji, that is, using the respective optimal culture conditions of Monascus and Aspergillus oryzae, fermenting whole broad beans with Aspergillus oryzae in a traditional manner, and fermenting broken broad beans with Monascus oryzae to improve the quality of fermented food. Compared with pure culture, the co-cultivation of composite bacterial agents may positively affect the production of enzyme mixtures, making up for the deficiency of a single enzyme system formed by a single strain. The color value of the bean paste prepared with the combined bacterial agent is significantly improved, the protease activity is high, the amino acid nitrogen and free amino acid content are high, and lovastatin with the function of lowering blood lipids is produced.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The invention provides a Monascus purpurogenous with a deposit number of CGMCC No: 41681.

[0006] The present invention also provides the use of the above-mentioned Monascus in preparing fermented food;

[0007] The fermented food can be vinegar, wine, soy sauce, fermented bean curd, bean paste, fermented black beans or bean paste.

[0008] The present invention also provides a combined bacterial agent, comprising the above-mentioned Monascus and Aspergillus oryzae with a preservation number of CGMCC No: 23273.

[0009] In some specific embodiments of the present invention, the ratio of the spore counts of Monascus and Aspergillus oryzae in the above-mentioned combined bacterial agent is (10-30):(70-90).

[0010] The present invention also provides the use of the above-mentioned combined bacterial agent in the preparation of fermented food;

[0011] The fermented food can be vinegar, wine, soy sauce, fermented bean curd, bean paste, fermented black beans or bean paste.

[0012] The present invention also provides fermented food, which may be vinegar, wine, soy sauce, fermented bean curd, bean paste, fermented black beans or bean paste, comprising the above Monascus or the above combined bacterial agent.

[0013] In some specific embodiments of the present invention, the fermented food described in the fermented food is bean paste, and the preparation method thereof comprises:

[0014] Step (A1): treating broad bean peels at 70°C, 80°C, 90°C, 91°C, 92°C, 93°C, 94°C, 95°C, 96°C, 97°C, 98°C or 99°C for 10 s, 15 s, 20 s, 25 s or 30 s, mixing with water, setting the temperature to 40°C, 41°C, 42°C, 43°C, 44°C, 45°C, 46°C, 47°C, 48°C, 49°C or 50°C for 15 min, 20 min, 25 min or 30 min, draining the water, mixing with wheat flour to obtain broad bean peels coated with flour, wherein the mass ratio of the wheat flour to the broad bean peels after draining the water is (2-4):10;

[0015] Step (A2): mixing the powdered broad bean petals with the above-mentioned combined bacterial agent, culturing at 30° C., 31° C., 32° C., 33° C., 34° C. or 35° C. and a humidity of 87%, 88%, 89%, 90%, 91%, 92% or 93% for 18 h, 19 h, 20 h, 21 h or 22 h, or culturing at 27° C., 28° C. or 29° C. and a humidity of 77%, 78%, 79%, 80%, 81%, 82% or 83% for 18 h, 19 h, 20 h, 21 h or 22 h, to obtain broad bean koji;

[0016] Step (A3): Mix broad bean koji with salt water of the same mass, ferment until the amino acid nitrogen content is greater than 0.25 g / 100 g, and then mix with pepper fermented rice to obtain bean paste.

[0017] In some specific embodiments of the present invention, the broad bean buds described in the fermented food include complete broad bean buds and incomplete broad bean buds;

[0018] The mixing in step (A2) is as follows: the Aspergillus oryzae in the above-mentioned combined bacterial agent is mixed with the complete broad bean shells, and the Monascus purpureus in the above-mentioned combined bacterial agent is mixed with the incomplete broad bean shells.

[0019] The present invention also provides a method for preparing bean paste, comprising the following steps:

[0020] Step (B1): treating broad bean peels at 70°C, 80°C, 90°C, 91°C, 92°C, 93°C, 94°C, 95°C, 96°C, 97°C, 98°C or 99°C for 10 s, 15 s, 20 s, 25 s or 30 s, mixing with water, setting the temperature to 40°C, 41°C, 42°C, 43°C, 44°C, 45°C, 46°C, 47°C, 48°C, 49°C or 50°C for 15 min, 20 min, 25 min or 30 min, draining the water, mixing with wheat flour to obtain broad bean peels coated with flour, wherein the mass ratio of the wheat flour to the broad bean peels after draining the water is (2-4):10;

[0021] Step (B2): mixing the powdered broad bean petals with the above-mentioned combined bacterial agent, culturing at 30°C, 31°C, 32°C, 33°C, 34°C or 35°C and a humidity of 87%, 88%, 89%, 90%, 91%, 92% or 93% for 18 h, 19 h, 20 h, 21 h or 22 h, or culturing at 27°C, 28°C or 29°C and a humidity of 77%, 78%, 79%, 80%, 81%, 82% or 83% for 18 h, 19 h, 20 h, 21 h or 22 h to obtain broad bean koji;

[0022] Step (B3): Mix the broad bean koji with the same mass of salt water, ferment until the amino acid nitrogen content is greater than 0.25 g / 100 g, and then mix with pepper fermented rice to obtain bean paste.

[0023] In some specific embodiments of the present invention, the broad bean petals described in the above preparation method include complete broad bean petals and incomplete broad bean petals;

[0024] The mixing in step (B2) is as follows: mixing the Aspergillus oryzae in the above-mentioned combined bacterial agent with the complete broad bean shells, and mixing the Monascus purpureus in the above-mentioned combined bacterial agent with the incomplete broad bean shells.

[0025] In some specific embodiments of the present invention, the above preparation method further comprises:

[0026] Step (C1): treating broad bean petals at 70°C, 80°C, 90°C, 91°C, 92°C, 93°C, 94°C, 95°C, 96°C, 97°C, 98°C or 99°C for 10 s, 15 s, 20 s, 25 s or 30 s, mixing with water, setting the temperature to 40°C, 41°C, 42°C, 43°C, 44°C, 45°C, 46°C, 47°C, 48°C, 49°C or 50°C for 15 min, 20 min, 25 min or 30 min, draining the water, mixing with wheat flour to obtain broad bean petals coated with flour, wherein the mass ratio of the wheat flour to the broad bean petals after draining the water is (2-4):10, and the broad bean petals include complete broad bean petals and incomplete broad bean petals;

[0027] Step (C2): mixing Aspergillus oryzae with a preservation number of CGMCC No: 23273 with the complete broad bean fraction to obtain a mixture 1; mixing Monascus AXZ-2 with the incomplete broad bean fraction to obtain a mixture 2; culturing the mixture 1 and the mixture 2 respectively, wherein the culturing process is: culturing at 30°C, 31°C, 32°C, 33°C, 34°C or 35°C and a humidity of 87%, 88%, 89%, 90%, 91%, 92% or 93% for 18 h, 19 h, 20 h, 21 h or 22 h, and culturing at 27°C, 28°C or 29°C and a humidity of 77%, 78%, 79%, 80%, 81%, 82% or 83% for 18 h, 19 h, 20 h, 21 h or 22 h, respectively obtaining broad bean koji fermented by Aspergillus oryzae and broad bean koji fermented by Monascus;

[0028] Step (C3): mixing the broad bean koji fermented by Aspergillus oryzae and the broad bean koji fermented by Monascus to obtain a broad bean koji mixture, mixing the broad bean koji mixture with an equal mass of salt water, fermenting until the amino acid nitrogen content is greater than 0.25 g / 100 g, and then mixing with pepper fermented rice to obtain bean paste.

[0029] The present invention also provides a combined bacterial agent of Monascus AXZ-2 and Aspergillus oryzae AZ-01.

[0030] The present invention also provides use of the above-mentioned combination of Monascus AXZ-2 and Aspergillus oryzae AZ-01 in food fermentation. In one embodiment, the food fermentation is sauce fermentation. In another embodiment, the food fermentation is soy sauce fermentation.

[0031] The present invention also provides the use of the above-mentioned combination of Monascus AXZ-2 and Aspergillus oryzae AZ-01 in koji making. In one embodiment, the koji obtained by koji making is used for fermentation of bean paste.

[0032] The present invention also provides a use of the above-mentioned combined bacterial agent of Monascus AXZ-2 and Aspergillus oryzae AZ-01 in improving the flavor and color of fermented soybean paste.

[0033] The combined bacterial agent of the present invention and its application in Pixian bean paste have the following effects:

[0034] The combined bacterial agent of Monascus AXZ-2 and Aspergillus oryzae AZ-01 provided by the invention has high protease yield, and the prepared bean paste has good color and flavor.

[0035] The combined bacterial agent of Monascus AXZ-2 and Aspergillus oryzae AZ-01 provided by the present invention is applied to fermentation of bean paste, so that the fermented bean paste has high amino acid content and high free amino acid content, and produces lovastatin with the function of lowering blood lipids.

[0036] Biological Deposit Description

[0037] Biological material: AXZ-2, classification name: Monascus pilosus, deposited on December 4, 2024 in the General Microbiological Center of China Culture Collection Administration, the address of the collection center is: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing; the collection number is CGMCC No: 41681.

[0038] The AXZ-2 described in the present invention is the Monascus rubrum with the above-mentioned deposit number CGMCC No: 41681. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0040] Figure 1A Shows the morphology of AXZ-2 strain;

[0041] Figure 1B Shown is the morphology of the AXZ-2 strain. DETAILED DESCRIPTION

[0042] The present invention discloses a Monascus-Aspergillus oryzae combined bacterial agent and its application in Pixian Douban. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve it. It is particularly important to point out that all similar substitutions and modifications are obvious to those skilled in the art, and they are all considered to be included in the present invention. The method and application of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

[0043] The Aspergillus oryzae AZ-01 involved in the present invention is deposited in the China General Microbiological Culture Collection Center (CGMCC for short), with a deposit number of CGMCC No: 23273. The address of the depository is No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. The deposit date is October 8, 2021, and it is disclosed in application number CN202211144935.8.

[0044] The Monascus AXZ-2 involved in the present invention is deposited in the China General Microbiological Culture Collection Center (CGMCC for short), with a deposit number of CGMCC No: 41681. The address of the depository is No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, and the deposit date is December 4, 2024.

[0045] The Monascus AXZ-2 is separated and purified from traditional vinegar koji and obtained by ultraviolet mutagenesis, one of the well-known mutagenesis methods. It is safe to be used in brewing fermented foods such as soybean paste, soy sauce, fermented black beans, and fermented bean paste.

[0046] The morphological characteristics of the AXZ-2 strain are as follows Figure 1A , Figure 1B shown.

[0047] It should be understood that the expression "one or more of..." includes each of the items recited after the expression individually and in various different combinations of two or more of the recited items, unless otherwise understood from the context and usage. The expression "and / or" in combination with three or more recited items should be understood to have the same meaning, unless otherwise understood from the context.

[0048] The use of the terms "comprising", "having" or "containing", including their grammatical synonyms, should generally be understood as open and non-restrictive, for example not excluding other unrecited elements or steps, unless otherwise specifically stated or otherwise understood from the context.

[0049] It should be understood that the order of steps or the order in which certain actions are performed is not important as long as the present invention remains operable. In addition, two or more steps or actions may be performed simultaneously.

[0050] The use of any and all examples or exemplary language, such as "for example" or "including", herein is intended only to better illustrate the invention and does not limit the scope of the invention unless otherwise claimed. No language in this specification should be construed as indicating that any non-claimed element is essential to the practice of the invention.

[0051] In addition, the numerical ranges and parameters used to define the present invention are approximate values, and the relevant values ​​in the specific embodiments have been presented as accurately as possible. However, any numerical value inherently inevitably contains standard deviations due to individual test methods. Therefore, unless otherwise expressly stated, it should be understood that all ranges, quantities, values ​​and percentages used in this disclosure are modified by "about". Here, "about" generally means that the actual value is within plus or minus 10%, 5%, 1% or 0.5% of a specific value or range.

[0052] Unless otherwise specified, the raw materials, reagents, consumables and instruments involved in the present invention are all common commercial products and can be purchased from the market.

[0053] The present invention will be further described below in conjunction with embodiments:

[0054] Example 1: Mutation breeding and screening of Monascus strains

[0055] 1. Methods

[0056] (1) Activation of strains: Dissolve the Monascus strains preserved by vacuum freeze drying with sterile water or culture medium, transfer to fresh culture medium with a sterile pipette, and culture at an appropriate temperature. Perform pure slant culture on the activated strains and pass them twice. The starting strains were isolated and purified by the inventors from vinegar koji of Chengdu Guoniang Food Co., Ltd., Sichuan Province.

[0057] The strain adopts PDA culture medium: 24 g potato glucose; 20 g agar; 1 L of deionized water with 0.1 g / L chloramphenicol, sterilized at 120°C for 20 min. The culture temperature of the culture medium is 32-33°C, and the culture time is 3-4 days.

[0058] (2) Preparation of single-cell bacterial suspension: Add 5 mL of sterile saline to several Monascus slants, scrape and wash the spores on the slants, collect the bacterial suspension, add glass beads, shake and disperse, and then filter with absorbent cotton or filter paper to obtain a spore count of 10 6 Bacterial suspension of cells / ml.

[0059] The spore number is counted by plate counting method, and filtration with absorbent cotton or filter paper can make the spores dispersed evenly.

[0060] (3) Mutagenesis of strains: The bacterial suspension prepared in step (2) is divided into multiple culture dishes. A magnetic bar is placed on each culture dish, and the culture dish with the magnetic bar placed is opened and placed on the magnetic stirrer of the mutagenesis box for ultraviolet mutagenesis. The power of the ultraviolet lamp is 15 watts, and the ultraviolet mutagenesis operation time is 5 min, 7 min, 9 min, 10 min, 11 min, 13 min, and 15 min, respectively. After the mutagenesis is completed, the bacterial suspension is evenly spread on a high-salt wort medium plate, 32~33°C, culture time 2~3 days, culture time 2 days, and several target colonies are obtained. Select single colonies with fast growth rate, strong mycelium, and large and full colonies on the culture medium for the next step of screening.

[0061] (4) The target colonies obtained in step (3) were inoculated by the plate spot inoculation method. The specific method is to use an inoculation needle dipped in a little sterile physiological saline to pick up a small amount of spores on the slope, and gently spot them on the casein medium in the form of a dot in the middle, with three parallels for each strain. Culture at 32.5℃ for 4 days, and then observe the colony diameter, transparent zone size, etc. of each strain. The ratio of the transparent zone diameter to the colony diameter Hc can reflect the protease production ability of the Aspergillus. Hc = transparent zone diameter / colony diameter. Casein medium: casein 4 g; KH2PO4 0.36 g; MgSO4·7H2O 0.50 g; Na2HPO4 1.07 g; agar powder 20.0 g; distilled water 1000 mL, pH 6.5-7.0. The strains with fast growth rate, large circle diameter ratio, good spore attachment and neutral protease were selected and transplanted on bean juice slant medium, subcultured twice, and preserved for the next step of screening.

[0062] (5) The strains preserved in (4) were used to screen for high-yield amylase strains using a liquid amylase-producing medium. The medium contained 0.3% beef extract, 1% peptone, 0.5% NaCl, a fermentation temperature of 30°C, and a fermentation pH of 5.0. The selected strains with high amylase production were transplanted onto a soybean juice slant medium, subcultured twice, and preserved for the next step of screening.

[0063] (6) Soak 20 g of indica rice for 5 h and transfer it into a 250 mL conical flask. After sealing, sterilize it at 120°C and 0.1 MPa for 20 min. Then, pat the rice grains loose while they are still hot and inoculate the Monascus from step (5). Mix well so that the culture medium is piled up in one corner of the flask. Incubate at 30°C for 48 to 72 h and then shake it loose and flatten it. Thereafter, shake the flask once every 24 h until red yeast rice is produced. Select the Monascus strain with the best color and value.

[0064] A Monascus strain was screened out, which has the characteristics of high production of protease and lovastatin, fast growth rate, strong reproduction ability, ability to produce red yeast rice, and short spore production time.

[0065] Example 2: Preparation of high-quality Monascus-Aspergillus oryzae combined bacterial agent

[0066] (1) Preparation of conidia suspension

[0067] Use a sterile inoculation loop to scrape appropriate amounts of spores from the storage slopes of Monascus AXZ-2 and Aspergillus oryzae AZ-01 obtained by the present invention and inoculate them on PDA culture medium plates, place them in a 30°C constant temperature incubator for 3 to 5 days, and after sufficient spore production, add an appropriate amount of sterile water to each plate, gently scrape the mycelial surface with a sterile coating stick to scrape off the spores. Shake the collected spore eluate, count with a hemocytometer, and obtain the concentration of the spore suspension mother solution.

[0068] (2) Preparation of high-quality Monascus-Aspergillus oryzae combined inoculant

[0069] The conidia suspensions of the above two strains were diluted and mixed according to the ratio to obtain the following bacterial agents with different ratios:

[0070] The composition of microbial agent 1 is: the spore count of Monascus AXZ-2 accounts for 10%, the spore count of Aspergillus oryzae AZ-01 accounts for 90%, and the total spore count is 1.0×10 8 ;

[0071] The composition of microbial agent 2 is: the spore count of Monascus AXZ-2 accounts for 20%, the spore count of Aspergillus oryzae AZ-01 accounts for 80%, and the total spore count is 1.0×10 8 ;

[0072] The composition of microbial agent 3 is: the spore count of Monascus AXZ-2 accounts for 30%, the spore count of Aspergillus oryzae AZ-01 accounts for 70%, and the total spore count is 1.0×10 8 .

[0073] Example 3: Application of Monascus-Aspergillus oryzae composite bacterial agent in the preparation of bean paste

[0074] (1) Broad bean koji process: scald the broad bean peels at 95℃ for 20 seconds, soak the broad beans in 45℃ water for 20 minutes, drain the water and coat them with flour according to the mass ratio of wheat flour to broad bean peels of 3:10. Add 5% seed koji according to the proportion of bacterial agent 1, mix well and culture at a constant temperature. Culture conditions: control the temperature at 33℃±2 and the humidity at 90%; turn the koji when the koji temperature is ≥37 degrees to avoid burning the koji (generally turn the koji 1~2 times), and end the koji making after 48 hours.

[0075] (2) Post-fermentation process: The cultured broad bean koji and 30% salt water are sealed and fermented in a mass ratio of 1:1 to enter the sweet bean fermentation stage. The fermentation is carried out at a constant temperature of 44℃±2 for 35 days until the amino acid nitrogen content is greater than 0.25 g / 100 g to obtain sweet bean. The sweet bean is mixed with pepper fermented wine and fermented for at least 3 months to obtain mature Pixian bean.

[0076] The preparation method of the pepper fermented rice is as follows.

[0077] Fresh peppers are washed, and foreign matters such as pepper stems, mud, stones and pepper leaves are removed from the fresh peppers. The fresh peppers are crushed using a special pepper crusher, and the sieve aperture used by the crusher is 16 mm.

[0078] Salted pepper fermentation management:

[0079] - Adding salt: When putting the crushed fresh peppers into the pond, salt must be added at a ratio of 16% to 18%. The principle of adding salt is to add salt in a gradual manner, that is, less at the bottom and more at the top, with a layer of pepper mash and a layer of salt.

[0080] -Amount of pepper mash added to the pool: When adding the pepper mash, the surface of the fresh pepper mash should be 20 to 30 cm away from the pool surface.

[0081] -Circulation management of pepper mash water: the pepper mash that has just been put into the pond must be circulated with salt water at least once a day. During the circulation, the entire pond surface must be sprinkled with salt water to ensure uniform salt distribution. If the pepper mash swells, becomes hot, or there are abnormal phenomena on the surface of the salt pond, the frequency of brine circulation and the circulation time should be increased.

[0082] -Sealing the pool: After the pepper mash water has been circulated for a week, notify the laboratory technician to conduct a test. When the salt content reaches a balance, the pool will be sealed. First, level the pepper mash and press it tightly around the pool. Evenly sprinkle a layer of salt on the surface of the pepper mash. Use salt to level the compressed pool. Then cover it with plastic film. Press the plastic film and the pool edge with salt (the observation hole should also be covered tightly) to prevent air from entering.

[0083] Example 4: Application of Monascus-Aspergillus oryzae composite bacterial agent in the preparation of bean paste

[0084] 5% seed koji was added according to the proportion of bacterial agent 2, and the rest was the same as Example 3.

[0085] Example 5: Application of Monascus-Aspergillus oryzae composite agent in the preparation of bean paste

[0086] 5% seed koji was added according to the proportion of bacterial agent 3, and the rest was the same as Example 3.

[0087] Example 6: Application of Monascus-Aspergillus oryzae composite bacterial agent in the preparation of bean paste

[0088] Due to the different particle sizes of broad beans, in order to optimize the fermentation conditions of broad beans of different particle sizes, the broad bean petals are screened and divided into whole and finely crushed ones, and the proportion of microbial agent 2 is selected, that is, 5% Monascus koji is added to ferment the finely crushed broad bean petals according to the spore proportion of 20%, and 5% Aspergillus oryzae koji is added to ferment the whole broad bean petals according to the spore proportion of 80%. The culture conditions are as follows: from 0 to 20 h, the temperature is controlled at 30 ° C and the humidity is 90%; from 20 h to the end, the temperature is controlled at 28 ° C and the humidity is 80%. After the composite microbial agents are kojied separately, they are mixed evenly and enter the sweet petal stage and the post-fermentation stage until the fermentation ends. Other conditions are the same as in Example 3.

[0089] Comparative Example 1: Traditional Pixian Douban

[0090] Comparative Example 1 is the traditional Pixian bean paste, which is different from Example 3 in that step 4 is inoculated with 3.042 koji of Aspergillus oryzae, which is common for bean paste, and the rest is the same.

[0091] Comparative Example 2: Traditional Pixian Douban + Sweet Pepper Powder

[0092] In the post-fermentation stage of Comparative Example 1, 1% (w / w) sweet pepper powder was added, and the rest was the same as that of Control 1.

[0093] Comparative Example 3: Application of Aspergillus oryzae 3.042 and Monascus AXZ-2 in the preparation of bean paste

[0094] The difference between Comparative Example 3 and Example 3 is that step 4 is inoculated with Aspergillus oryzae 3.042 and Monascus AXZ-2, which are commonly used for bean paste, and the rest are the same.

[0095] Comparative Example 4: Aspergillus oryzae AZ-01 and commercially available Monascus fungi

[0096] The difference between Comparative Example 4 and Example 3 is that in step 4, Aspergillus oryzae AZ-01 and commercially available Monascus (CICC5016 Monascus rubrum) are inoculated, and the rest are the same.

[0097] Effect example: test indicators

[0098] The determination standards and literature for related indicators of bean paste are as follows.

[0099] Protease activity: Refer to "Application of High Protease Activity Aspergillus oryzae BL18 in Koji Making and Fermentation of Bean Paste" for relevant content on the determination of bean paste protease activity.

[0100] Amino acid nitrogen: refer to GB18186-2000 "Brewed soy sauce".

[0101] Colorimetric method: refer to GB / T 5009.124-2003 "Determination of Amino Acids in Foods".

[0102] Free amino acid: GB / T 5009.124-2003 “Determination of amino acids in food” standard method was adopted.

[0103] Color value: GB 1886.181-2016 method is adopted.

[0104] Lovastatin content: Determined according to BJS 201710.

[0105] The scoring rules for the flavor of bean paste are as follows.

[0106] Color (20 points)

[0107] - Reddish brown, oily and shiny (16-20 points): Bright color, uniform reddish brown, with a natural oily luster on the surface.

[0108] -The color is reddish brown with a certain luster (11~15 points): The color is reddish brown with slightly poor gloss.

[0109] - Dull color, uneven reddish brown (0-10 points): lighter or darker color, dull, with obvious color difference.

[0110] Smell (30 points)

[0111] - Rich in soy sauce aroma, without any unpleasant odor (24-30 points): It has a rich soy sauce and ester aroma that is unique to bean paste, and the aroma is harmonious and pure.

[0112] -The sauce aroma is more obvious, with a slight peculiar smell (18~23 points): The sauce aroma is more prominent, but there is a faint unpleasant smell.

[0113] -The sauce flavor is light, and the peculiar smell is strong (0-17 points): The sauce flavor is weak, and there are obvious peculiar smells such as rancidity and rot.

[0114] Status (20 points)

[0115] - The bean curd is crispy and crumbly, with moderate viscosity (16-20 points): The bean curd particles are complete, crispy, with no residue after chewing, and the sauce has moderate viscosity.

[0116] -The bean curd is relatively crispy and less sticky (11-15 points): The bean curd particles are basically intact, the crispness is acceptable, and the viscosity is slightly higher or lower.

[0117] - The bean curd is not crispy, and the viscosity is too high or too low (0-10 points): The bean curd particles are too hard or too soft, and the sauce is too thin or too thick.

[0118] Taste (30 minutes)

[0119] -Spicy but not dry, with a mellow and long aftertaste (24-30 points): The spiciness is moderate, without a dry spicy feeling, and the aftertaste is rich in sauce aroma and mellow taste.

[0120] -Heavier or lighter spiciness, shorter aftertaste (18-23 points): The spiciness deviates from the moderate level, and the aftertaste is not long enough.

[0121] - Too spicy or too light, no aftertaste (0-17 points): The spiciness is too stimulating or almost non-spicy, and there is no aftertaste.

[0122] Table 1: Quality analysis of fermented bean paste in different examples

[0123]

[0124] As can be seen from Table 1, the core indicators of the bean paste brewed in the embodiment, such as protease activity, amino acid nitrogen content, and free amino acids, are higher than those of the control group, the flavor and color value are better than those of the control group, and lovastatin with the function of lowering blood lipids is detected.

[0125] The combined bacterial agent of Monascus AXZ-2 and Aspergillus oryzae AZ-01 provided by the present invention is applied to fermentation of bean paste, so that the fermented bean paste has high protease activity, amino acid nitrogen, free amino acids and lovastatin content, and the color value of the fermented bean paste is higher than that of a control group to which exogenous sweet pepper powder is added.

[0126] 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 principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. Monascus pilosus with a deposit number of CGMCC No: 41681.

2. Use of Monascus pilosus according to claim 1 in preparing fermented food.

3. A combined bacterial agent, characterized in that: The method comprises the Monascus pilosus as claimed in claim 1 and Aspergillus oryzae with a deposit number of CGMCC No: 23273.

4. The combined bacterial agent according to claim 3, characterized in that: The spore count ratio of the Monascus pilosus and the Aspergillus oryzae is (10-30):(70-90).

5. Use of the combined bacterial agent as claimed in claim 3 or 4 in the preparation of fermented food.

6. A fermented food, characterized in that The method comprises the Monascus pilosus as claimed in claim 1 or the combined bacterial agent as claimed in claim 3 or 4.

7. The fermented food according to claim 6, characterized in that The fermented food is bean paste, and the preparation method thereof comprises: Step (A1): treating broad bean peels at 70-99°C for 10-30 seconds, mixing with water, maintaining at 40-50°C for 15-30 minutes, draining the water, and mixing with wheat flour to obtain broad bean peels coated with flour, wherein the mass ratio of the wheat flour to the broad bean peels after draining the water is (2-4):10; Step (A2): mixing the powdered broad bean petals with the combined bacterial agent as claimed in claim 3 or 4, culturing at 30-35° C. and 87-93% humidity for 18-22 h, and culturing at 27-29° C. and 77-83% humidity for 18-22 h to obtain broad bean koji, with a total koji making time of 48 h; Step (A3): Mix broad bean koji with salt water of the same mass, ferment until the amino acid nitrogen content is greater than 0.25 g / 100 g, and then mix with pepper fermented rice to obtain bean paste.

8. The fermented food according to claim 7, characterized in that include: The broad bean petals include complete broad bean petals and incomplete broad bean petals; The mixing in step (A2) is as follows: mixing the Aspergillus oryzae in the combined bacterial agent as claimed in claim 3 or 4 with the whole broad bean petals, and mixing the Monascus pilosus in the combined bacterial agent as claimed in claim 3 or 4 with the incomplete broad bean petals.

9. A method for preparing bean paste, characterized in that: The steps include: Step (B1): treating broad bean peels at 70-99°C for 10-30 seconds, mixing with water, maintaining at 30-50°C for 15-30 minutes, draining the water, and mixing with wheat flour to obtain broad bean peels coated with flour, wherein the mass ratio of the wheat flour to the broad bean peels after draining the water is (2-4):10; Step (B2): mixing the powdered broad bean petals with the combined bacterial agent as claimed in claim 3 or 4, culturing at 40-35° C. and 87-93% humidity for 18-22 h, and culturing at 27-29° C. and 77-83% humidity for 18-22 h to obtain broad bean koji, with a total koji making time of 48 h; Step (B3): Mix the broad bean koji with the same mass of salt water, ferment until the amino acid nitrogen content is greater than 0.25 g / 100 g, and then mix with pepper fermented rice to obtain bean paste.

10. The preparation method according to claim 9, characterized in that: include: The broad bean petals include complete broad bean petals and incomplete broad bean petals; The mixing in step (B2) is: mixing the Aspergillus oryzae in the combined bacterial agent as claimed in claim 3 or 4 with the whole broad bean petals, and mixing the Monascus pilosus in the combined bacterial agent as claimed in claim 3 or 4 with the incomplete broad bean petals.

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