Method for synergistically fermenting low-salt raw thick broad-bean sauce by fusing Weissella and Candida angustifolia

Abstract

The invention relates to the technical field of bioengineering fermentation, and discloses a method for synergistically fermenting low-salt raw thick broad-bean sauce by fusing Weissella and Candida angustifolia, and the Weissella and Candida angustifolia are inoculated and fused to strengthen the fermentation function of the low-salt raw thick broad-bean sauce. The salinity of the low-salt raw thick broad-bean sauce prepared by fermentation with the method can be reduced to 8-10%, titratable acid is well controlled, and the color, flavor and typicality of the thick broad-bean sauce are all improved.

Description

Technical Field

[0001] The invention relates to the technical field of bioengineering fermentation, and in particular to a method for synergistically fermenting low-salt raw bean paste by fusing Weissella and Candida echeveria. Background Art

[0002] Doubanjiang is a traditional fermented food in my country. Doubanjiang has a unique flavor and rich nutrition. It occupies an important position in my country's long-standing food culture and is widely used in various condiments and seasonings. Doubanjiang production mainly uses broad beans, flour, salt and pepper as raw materials, and mainly goes through basic steps such as making koji with Aspergillus oryzae and adding salt water to make the sauce fermented. During the fermentation process of bean paste, macromolecules such as protein and starch in raw materials such as broad beans and flour are decomposed by microorganisms into small molecules such as amino acids, polypeptides, fatty acids, oligosaccharides and monosaccharides, which are easy for human body to absorb. In addition, microorganisms will convert small molecules into various secondary metabolites such as organic acids, alcohols, esters, etc. through their own growth and metabolic processes, thus giving the bean paste a unique flavor.

[0003] Weissella confusa belongs to the Prokaryotes, Bacteria, Firmicutes, Bacillus, Lactobacilales, Leuconostocaceae, and Weissella in taxonomy. The colonies of Weissella confusa are round, with neat edges, opaque, and white in color.

[0004] Starmerella etchellsii belongs to the Eukaryota, Fungi, Ascomycota, Saccharomyces, Saccharomyces, Saccharomyces, Saccharomyces, and Candida in taxonomy. The colony of Starmerella etchellsii is round, with a moist and smooth surface and a milky white color.

[0005] The fermentation of bean paste involves a complex microbial community, among which yeast and lactic acid bacteria play an important role in the fermentation process of bean paste. Lactic acid bacteria can decompose the protein and carbohydrates in the raw materials of bean paste into small molecular nutrients, and directly or indirectly participate in the fermentation of acid substances in the fermented mash through metabolism, so that the pH value of the fermented mash decreases in the early stage of fermentation, thereby inhibiting the growth of harmful microorganisms and ensuring the hygiene and safety of bean paste during the fermentation process. With the increase in the demand for healthy diet, reducing the salinity of bean paste has become an important demand of the seasoning industry in recent years. However, the reduction in salinity will bring about adverse conditions such as flavor changes and microbial contamination. The stability of the microbial community is a key factor in the formation of the flavor of bean paste. Among them, determining the key microorganisms and using them for bio-fortification inoculation can help maintain the stability of the flavor of bean paste. The lactic acid and some substances with special flavors formed by lactic acid bacteria during the fermentation of bean paste can improve the flavor and taste of bean paste. The lactic acid bacteria directly related to the flavor of bean paste are mainly Weissella, Staphylococcus and Lactobacillus. The enhanced application of Weissella microorganisms in fermented foods can increase the content of esters, aldehydes, alcohols, acids and ketones in the products, and has the effect of effectively improving the flavor and quality of fermented foods, such as bean paste, or shortening the fermentation time. Yeast can directly or indirectly participate in the formation of alcohols and acids in bean paste and participate in esterification during the fermentation process, thereby reducing the undesirable flavors in fermented foods and promoting a richer flavor of bean paste. In addition, yeast has an important influence on the formation of characteristic flavor substances of bean paste, such as phenylethanol and 4-ethylphenol. Yeasts closely related to the flavor of bean paste include Candida and Rouxyces. Candida microorganisms belong to the post-ripening ester-flavored yeast. Its reproduction and fermentation can effectively improve the flavor of bean paste and improve the quality of bean paste. Previous studies have shown that the action of lactic acid bacteria will reduce the pH of the fermented mash, forming an acidic fermented mash environment, thereby promoting the better growth of yeast strains such as Candida and Rouxyces. Traditional bean paste uses an open natural fermentation process, which has the risk of potential microbial contamination and a low degree of mechanization. Using important functional microorganisms to enhance the fermentation process of low-salt bean paste can help improve the flavor of the product and lay the foundation for future artificial controllable fermentation.

[0006] In view of the above problems, the present invention proposes a method for synergistically fermenting low-salt raw bean paste by fusing Weissella and Candida echeveria to solve the above problems. Summary of the invention

[0007] The invention provides a method for cooperatively fermenting low-salt raw bean paste by fusing Weissella and Candida echeveria.

[0008] The scheme of the present invention is:

[0009] A method for synergistically fermenting low-salt raw bean paste by fusion of Starmerella etchellsii and Candida etchellsii comprises the following steps: synergistically fermenting Candida etchellsii (Starmerella etchellsii) Y18 and fusion of Weissella (Weissella confusa) B1 to produce low-salt raw bean paste.

[0010] As a preferred technical solution, the Starmerella etchellsii Y18 is deposited in the General Microbiology Center of the China Microbiological Culture Collection Administration, with a deposit number of CGMCC No. 27820 and a deposit date of July 6, 2023. The deposit address is No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences.

[0011] As a preferred technical solution, the Weissella confusa B1 is deposited in the General Microbiological Center of the China Microbiological Culture Collection Administration, with a deposit number of CGMCC No.32015 and a deposit date of September 20, 2024. The deposit address is No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences.

[0012] As a preferred technical solution, when the raw bean paste is prepared by mixing the koji with salt water to start fermentation, the amount of Weissella B1 added is ≥1.0×10 6 CFU / g, Candida eischeri is the added amount of Candida eischeri Y18 ≥ 1.0×10 6 CFU / g, and the feeding ratio of the fused Weissella B1 to the Candida etschie Y18 is 1-10:1.

[0013] As a preferred technical solution, the salinity of the fermented mash is 80-120 g / L.

[0014] As a preferred technical solution, fermentation is carried out at 15-40°C.

[0015] As a preferred technical solution, the fermentation of bean paste is carried out for a total of 12 to 18 weeks, and the fermentation is turned over every 15 days.

[0016] The invention also discloses an application of a starter in preparing fermented bean food. The starter contains Starmerella etchellsii Y18 and Weissella confusa B1. The starter is used in broad bean paste, soybean paste and soy sauce.

[0017] The invention discloses a method for synergistically fermenting low-salt raw bean paste by fusion of Starmerella etchellsii and Candida etchellsii, comprising the following steps: synergistically fermenting Candida etchellsii (Starmerella etchellsii) Y18 and fusion of Weissella (Weissella confusa) B1 to produce low-salt raw bean paste.

[0018] Advantages of the present invention:

[0019] The method for synergistically fermenting low-salt raw bean paste by fusing Weissella B1 and Candida echeveria Y18 provided by the present invention is based on the co-inoculation of fusing Weissella B1 and Candida echeveria Y18 to strengthen the fermentation function, and the titratable acid in the low-salt raw bean paste prepared by this method is also controlled within a good range; the flavor substances such as alcohols and esters are also significantly improved, and the fermentation cycle of the low-salt raw bean paste is significantly shortened. Therefore, the fusion of Weissella B1 and Candida echeveria Y18 plays an important role in the industrial production process of low-salt raw bean paste, which is beneficial to improving the quality of the sauce.

[0020] The quality differences between naturally fermented bean paste and bean paste fermented by inoculating fusion of Weissella and Candida ectichia of the present invention were compared, and it was found that inoculating fusion of Weissella and Candida ectichia was beneficial to improving the key physical and chemical indicators of the product, and effectively improved the flavor and quality of low-salt raw bean paste. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] 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 will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 This is a diagram for analyzing the salinity tolerance of the fusion of Weissella B1 and Candida etschie Y18 in Example 2 of the present invention; wherein A is the fusion of Weissella B1, and B is Candida etschie Y18;

[0023] Figure 2 This is a diagram for analyzing the physicochemical metabolic characteristics of the fusion of Weissella B1 and Candida etschuenensis Y18 in Example 3 of the present invention; wherein A is total acid, B is amino acid nitrogen, C is organic acid, and D is amino acid;

[0024] Figure 3 This is an analysis chart of the volatile flavor substance production ability of the fusion of Weissella B1 and Candida etschie Y18 in Example 3 of the present invention; wherein A is the type of volatile flavor substance; B is the content of volatile flavor substance;

[0025] Figure 4 This is a diagram showing the physical and chemical index analysis of raw bean paste fermentation under different salinity conditions by fusion of Weissella B1 and Candida echeveria Y18 inoculation; wherein A is total acid, B is amino acid nitrogen, C is organic acid, and D is free amino acid;

[0026] Figure 5 This is an analysis diagram of volatile flavor substances in raw bean paste fermentation under different salinity conditions by fusion of Weissella B1 and Candida etschuenensis Y18 enhanced inoculation in Example 4 of the present invention; wherein A is the type of volatile flavor substances, B is the content of volatile flavor substances, C is OPLS-DA analysis, and D is cluster analysis;

[0027] Figure 6 This is a graph showing the flavor sensory scores of raw bean paste fermentation under different salinity conditions in Example 4 of the present invention after enhanced inoculation with Weissella B1 and Candida ecteina Y18. DETAILED DESCRIPTION

[0028] The invention provides a method for cooperatively fermenting low-salt raw bean paste by fusing Weissella and Candida echeveria.

[0029] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below in conjunction with specific embodiments.

[0030] Example 1 Cultivation of Fusion of Weissella B1 and Candida etschuenensis Y18 Strains

[0031] Preparation of PDA medium: weigh 200g of commercially available non-sprouting and deteriorated potatoes, add appropriate amount of water and steam until cooked, filter the filtrate, add 20g of glucose, and dilute to 1L with deionized water. If solid culture medium is required, add 20g of agar to the above liquid culture medium.

[0032] Preparation of YPD medium: Weigh 20 g glucose, 20 g peptone and 10 g yeast powder, and dilute to 1 L with deionized water.

[0033] Preparation of MRS medium: weigh 20 g glucose, 10 g peptone, 10 g beef extract, 5 g yeast powder, 5 g sodium acetate, 2 g diammonium hydrogen citrate, 2 g dipotassium hydrogen phosphate, 1.0 mL Tween-80, 0.58 g magnesium sulfate and 0.25 g manganese sulfate, and dilute to 1 L with deionized water.

[0034] The commonly used fermentation agent of bean paste, Aspergillus oryzae 3.042, was inoculated into PDA slant solid culture medium and cultured at 28°C for 2 to 3 days.

[0035] Candida echinocipitae Y18 was inoculated into YPD liquid culture medium at a 1% inoculation rate, and cultured at 30° C. and 200 rpm with shaking for 12 to 18 hours until the middle and late logarithmic growth period.

[0036] The fused Weissella B1 was inoculated into MRS liquid culture medium at an inoculum amount of 1%, and statically cultured at 35° C. for 16-24 hours until the middle and late stages of logarithmic growth.

[0037] Example 2 Salinity tolerance experiment of fusion strains of Weissella B1 and Candida echinociparum Y18

[0038] MRS culture medium and YPD culture medium with different salt concentrations (4%, 8%, 10%, 12%, 16%, 20%, 24%, w / v) were prepared respectively.

[0039] Fusion Weissella B1 and Candida echinocarpa Y18 were cultured in MRS medium and YPD medium to the logarithmic growth phase, respectively. The cultured bacterial solution was transferred to the corresponding medium containing different salt concentrations at a 1% inoculum (v / v). After culturing for 3 days, the OD of the cultured bacterial solution was measured. 600 value to evaluate its salinity tolerance.

[0040] like Figure 1 As shown, the Candida echeveria Y18 strain has a high salt tolerance. The strain can still grow at a salinity of 20%, and is less inhibited at a salinity of 12-16%. Compared with Candida echeveria Y18, the salt tolerance of Weissella fusion B1 is relatively low. The strain can grow at a salinity of 12-16%, but the growth rate is limited, and its growth ability is relatively strong under a salinity of 8-10%. Since the salinity during the fermentation of raw bean paste is 12-18%, Weissella fusion B1 and Candida echeveria Y18 can grow in the high-salt environment of bean paste, and the growth of Weissella fusion will improve when the salinity decreases.

[0041] Example 3 Metabolic Characteristics Analysis Experiment of Fusion of Weissella B1 and Candida etschuenensis Y18 Strains

[0042] The metabolic characteristics of the fusion of Weissella B1 and Candida etschuenensis Y18 strains were analyzed using in vitro culture and fermentation method.

[0043] Prepare the simulated fermentation medium for bean paste: weigh 10g broad bean powder, 2.5g wheat flour, 50g fresh fermented soybean paste and 100g sodium chloride, add 1.0L deionized water, boil for 30min and filter through a filter bag or filter paper. The clear liquid is the simulated fermentation medium for bean paste. 6 CFU·g -1Inoculation amount: The fusion strains of Weissella B1 and Candida escheyenne Y18 were inoculated into the simulated fermentation medium of bean paste. The inoculation amount of the strains in the initial stage of fermentation was 1×10 6 CFU / g. The above culture medium was placed at 30°C for 3 days. After the fermentation, the metabolite index of the fermentation liquid of the strain was determined;

[0044] Among them, the total acid and amino acid nitrogen contents in the fermentation broth were determined in reference to the national standards "Determination of Total Acid in Food" (GB 12456-2021) and "Determination of Amino Acid Nitrogen in Food" (GB 5009.235-2016), and the organic acid content in the fermentation broth was determined by high performance liquid chromatography. The content and type of volatile flavor substances in the fermentation broth were determined by headspace solid phase microextraction gas chromatography-mass spectrometry. The protease activity and amylase activity in the fermentation broth were determined by the Folin phenol method and 3,5-dinitrosalicylic acid method. The uninoculated microbial sample was used as the blank, and three parallel groups were set up for each experiment. Figure 2 As shown in A and 2B, inoculation of fused Weissella B1 in the simulated medium helps to increase the accumulation of total acid and amino acid nitrogen in the medium, while the inoculation of Candida ectrichia Y18 consumes acidic substances and amino acid nitrogen in the medium. The total acid and amino acid nitrogen contents in the fermentation broth inoculated with fused Weissella B1 increased by about 1.6g / 100g and 0.015g / 100g compared with the blank, while the growth of Candida ectrichia Y18 consumed about 0.5g / 100g total acid and 0.01g / 100g amino acid nitrogen. Further analysis of the contents of the two main organic acids in the fermentation broth revealed that fused Weissella B1 had a higher ability to produce acetic acid and lactic acid, while the inoculation of Candida ectrichia Y18 consumed both acetic acid and lactic acid ( Figure 2 C). The activities of amylase and protease in the fermentation broth were determined, and it was found that Weissella fusion B1 had a certain ability to produce protease and amylase, while Candida eicherii Y18 did not have the corresponding ability ( Figure 2 D).

[0045] On this basis, the volatile flavor substances of the fusion strains of Weissella B1 and Candida echeveria Y18 after fermentation in the simulated medium of bean paste were further determined. Figure 3As shown, Candida echeveria Y18 showed a better ability to produce volatile flavor substances, while the corresponding ability of fused Weissella B1 was weaker. Inoculation of Candida echeveria Y18 can effectively increase the types of ester, alcohol, acid, ketone, phenol and heterocyclic volatile flavor substances in the fermentation broth, and greatly increase the content of ester, aldehyde, alcohol, acid and phenol substances (p<0.05). Fusion of Weissella B1 can increase the types and content of acid volatile flavor substances. The above results show that fused Weissella B1 has a strong ability to produce acid, while Candida echeveria Y18 has a good ability to produce volatile flavor substances.

[0046] Example 4 Application of the Fusion of Weissella B1 and Candida echeveria Y18 in Low-salt Raw Bean Paste Fermentation

[0047] In order to verify the functional characteristics of the fusion of Weissella B1 and Candida echeveria Y18 in the synergistic fermentation of bean paste under reduced salinity conditions, the two strains of microorganisms were inoculated into the fermentation process of raw bean paste under 8%, 10% and 12% salinity conditions. The washed broad beans were treated in warm water at 35-40℃ for 1-2h, and the broad beans were continuously stirred. After cooling to room temperature, the water was drained and mixed with wheat flour (4:1, w / w); and 1×10 6 CFU·g -1 The spore liquid of A.oryzae 3.042 was inoculated and cultured at 30℃ for 72h to obtain the finished koji. The finished koji was mixed with salt water of different concentrations to obtain 10% and 12% salinity mash, and the fused Weissella B1 and Candida echeveria Y18 cultured to the logarithmic phase were added at 1×10 6 CFU·g -1 The functional microorganisms (based on the mass of fermented mash) were co-inoculated into different salinity fermented bean pastes for bio-fortified fermentation, and 8%, 10% and 12% salinity fermented bean pastes without inoculation were used as controls. Three parallels were prepared for each sample. After the fermentation, the physical and chemical properties and volatile flavor substances of the fermented bean pastes in the bio-fortified group and the control group were measured, and the flavor sensory evaluation was performed. Figure 4 A It can be seen that as the salinity decreases from 12% to 8%, the total acid content of the fermented bean paste gradually increases. After inoculation with the fusion of Weissella B1 and Candida ectichia Y18, the total acid content of the fermented bean paste in the enhanced group (Group S) was significantly lower than that in the control group (Group B). Under the salinity conditions of 8% and 10%, the total acid content of the fermented bean paste (Group S) inoculated with the fusion of Weissella B1 and Candida ectichia Y18 (1.44g / 100g and 1.42g / 100g) was significantly lower than that of the blank group with the corresponding salinity (1.63g / 100g and 1.53g / 100g, p<0.05). Figure 4As shown in Figure B, the acetic acid content (3.71 g / 100 g and 3.60 g / 100 g) and lactic acid content (1.12 g / 100 g and 1.00 g / 100 g) of the fermented soybeans in the biofortification group at 8% and 10% salinity were lower than those in the control group (4.08 g / 100 g and 3.95 g / 100 g) and lactic acid content (1.18 g / 100 g and 1.28 g / 100 g, Figure 4 B). The amino acid nitrogen content of bean paste fermented material gradually increases with decreasing salinity ( Figure 4 C). The amino acid nitrogen content of the biofortified group at 8% and 10% salinity was 0.97g / 100g and 0.88g / 100g, respectively, slightly higher than that of the control group (0.96g / 100g and 0.85g / 100g). The composition and content of free amino acids in the control group and the fortified group were further determined. The contents of glutamic acid, lysine and leucine in the mash of the control group and the fortified group were relatively high ( Figure 4 D). Under the same salinity, the free amino acid content of the fermented soybeans in the fortified group and the control group was not much different. It can be seen that the biofortification inoculation of the fusion of Weissella B1 and Candida eischerichia Y18 in the raw soybean paste with reduced salinity can control the acidity of the fermented soybean paste while increasing the amino acid nitrogen content of the raw soybean paste, thereby avoiding the destruction of the flavor of the soybean paste.

[0048] On this basis, the volatile flavor substances of the fermented soybean paste obtained by the control group and the biofortification group at 8%, 10% and 12% salinity were determined by headspace solid phase microextraction-gas chromatography-mass spectrometry. Among all the samples, a total of 145 volatile flavor substances were determined, including 30 alcohols, 42 esters, 24 aldehydes, 7 acids, 5 phenols, 11 ketones, 7 heterocyclic substances and 19 alkane-olefin volatile flavor substances. The composition of volatile flavor substances between the control group (group B) and the biofortification group (group S) inoculated with fusion Weissella B1 and Candida ectechiae Y18 under different salinity conditions was significantly different. The inoculation of fusion Weissella B1 and Candida ectechiae Y18 significantly increased the types and contents of volatile flavor substances in raw bean paste. Figure 5 As shown in A and 5B, the fermented bean paste in the 8% salinity biofortification group contained more esters, ketones and heterocyclic substances, and contained higher concentrations of alcohols and esters; while the fermented bean paste in the 10% salinity biofortification group contained more aldehydes and phenols, and the content of alcohols and esters was also higher. The OPLS-DA model was further used to analyze the difference in the composition of volatile flavor substances in the fermented bean paste in the control group and the biofortification group obtained by fermentation at 8%, 10% and 12% salinity. It was found that the composition of volatile flavor substances in the fermented bean paste in the biofortification group was significantly different from that in the control group ( Figure 5C). Cluster analysis showed that the blank fermented bean paste fermented at 10% and 12% salinity were grouped into one category, the blank fermented bean paste fermented at 8% salinity were grouped into another category, and the biofortified fermented bean paste fermented at 8% and 10% salinity inoculated with Weissella fusion B1 and Candida echinociprix Y18 were grouped into another category.

[0049] The bean paste flavor evaluation panel (20 people, 10 men and 10 women) was formed to evaluate the flavor of the 8%, 10%, and 12% salinity blank group and the 8% and 10% salinity bio-fortification group raw bean paste from five dimensions: color, body, sauce aroma, fruity aroma, and typicality. Figure 6 As shown, in the blank group, the reduction of salinity will destroy the flavor of the bean paste. The color of the blank group fermented at 8% salinity is darker, the mash is thinner, and the sauce and fruit aroma are weaker. After inoculation with the fusion of Weissella B1 and Candida echeveria Y18, the sauce and fruit aroma of the biofortified group at 8% and 10% are more intense, the color is better, and the bean paste flavor is more typical. The bean paste of the biofortified group fermented at 8% salinity has a better fruity aroma, while the bean paste of the fortified group fermented at 10% salinity has a better sauce aroma and typicality. It can be seen that the inoculation of the fusion of Weissella B1 and Candida echeveria Y18 is beneficial to improving the flavor of the bean paste under reduced salinity conditions and compensating for the adverse effects of reduced salinity on the fermentation of bean paste.

[0050] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for synergistically fermenting low-salt raw bean paste by fusing Weissella and Candida echeveria, characterized in that: The method comprises the following steps: co-fermenting Starmerella etchellsii Y18 and Weissella confusa B1 to produce low-salt raw bean paste.

2. The method for cooperatively fermenting low-salt raw bean paste by fusing Weissella and Candida echeveria as claimed in claim 1, characterized in that: The Starmerella etchellsii Y18 is deposited in the General Microbiology Center of the China Microbiological Culture Collection Administration, with the deposit number CGMCC No. 27820 and the deposit date July 6, 2023.

3. The method for cooperatively fermenting low-salt raw bean paste by fusing Weissella and Candida echeveria as claimed in claim 1, characterized in that: The Weissella confusa B1 is deposited in the General Microbiology Center of China Microorganism Culture Collection Administration, with the deposit number CGMCC No.32015 and the deposit date September 20, 2024.

4. The method for cooperatively fermenting low-salt raw bean paste by fusing Weissella and Candida echeveria as claimed in claim 1, characterized in that: In the preparation of the raw bean paste, when the koji is mixed with salt water to start fermentation, the amount of Weissella B1 added is ≥1.0×10 6 CFU / g, Candida eicheni is the added amount of Candida eicheni Y18 ≥1.0×10 6 CFU / g, and the feeding ratio of the fused Weissella B1 to the Candida etschie Y18 is 1-10:

1.

5. A method for cooperatively fermenting low-salt raw bean paste by fusing Weissella and Candida echeveria as claimed in claim 1 or 4, characterized in that: The salinity of the mash is 80-120g / L.

6. A method for cooperatively fermenting low-salt raw bean paste by fusing Weissella and Candida etschulensis as claimed in claim 1 or 4: fermenting at 15-40°C.

7. A method for cooperatively fermenting low-salt raw bean paste by fusing Weissella and Candida echeveria as claimed in claim 1 or 4, characterized in that: The fermentation of bean paste takes a total of 12 to 18 weeks, and the fermentation is turned over every 15 days.

8. Use of a fermentation agent in preparing fermented bean food, characterized in that: The fermentation agent contains Starmerella etchellsii Y18 and Weissella confusa B1, and the fermentation agent is used in broad bean paste, soybean paste and soy sauce.

Images