A salt-loving tetrasphaera and its application in soy sauce production

Abstract

The application belongs to the technical field of food fermentation, and particularly relates to a salt-tolerant tetragenoccus and application thereof in soy sauce fermentation. The application provides a salt-tolerant tetragenoccus dy-8, which is preserved in the China General Microbiological Culture Collection Center, and has a preservation number of CGMCC No. 7.713 and a preservation date of March 17, 2026. The salt-tolerant tetragenoccus dy-8 is used as a microbial intensive fermentation agent, is inoculated into soy sauce mash at the beginning of soy sauce mash fermentation, and continues to ferment until the end of brewing. Compared with a common fermentation sample without inoculation of the dy-8, the content of a plurality of key aroma substances in the obtained soy sauce after inoculation of the dy-8 is increased, the content of 2-phenylethylamine, tyramine and the like is reduced, and the dy-8 can be used for improving the flavor quality of soy sauce and improving the edible safety.

Description

Technical Field

[0001] This invention belongs to the field of food fermentation technology, specifically relating to a halophilic tetracoccus and its application in soy sauce production. Background Technology

[0002] Soy sauce is an indispensable traditional condiment. Its unique color, aroma, and flavor mainly originate from the complex metabolic activities of the microbial community during the koji-making and fermentation process. During the long fermentation cycle, the growth, metabolism, and community succession of salt-tolerant microorganisms such as Tetracoccus have a significant impact on the flavor quality and safety of the final product.

[0003] Traditional soy sauce brewing relies on the participation of microorganisms in the natural environment. While this process imparts complex regional flavor characteristics to the product, it also presents challenges such as long fermentation cycles, poor batch stability, and uncontrollable flavor compound formation. With increasing consumer demand for high-quality soy sauce, improving its aroma quality to make it more intense and its ester aroma more prominent has become a key direction for technological upgrading in the industry. On the other hand, biogenic amines are a class of biologically active nitrogen-containing low-molecular-weight organic compounds widely present in fermented foods. During fermentation, the amino acid decarboxylase activity of microorganisms may lead to the excessive accumulation of biogenic amines such as histamine and tyramine. Excessive intake of biogenic amines may cause adverse reactions such as headaches and abnormal blood pressure, posing a potential threat to human health. Therefore, effectively controlling or reducing the content of biogenic amines in the finished product while improving the flavor of soy sauce is an important issue in ensuring the safety of soy sauce food.

[0004] In existing technologies, screening for superior microbial strains with specific functions and adding them back into the fermentation mash for enhanced fermentation is an effective means of improving product quality. However, existing strains cannot simultaneously improve flavor and reduce biogenic amines. Summary of the Invention

[0005] The present invention aims to provide a halophilic tetracoccus and its application in soy sauce fermentation, in order to solve the problem that some functional strains in the prior art are difficult to achieve both flavor improvement and reduction of biogenic amines.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: The technical solution of this invention uses halophilic tetracoccus dy-8 as the core, and uses it as an enhanced fermentation strain for initial inoculation of soy sauce mash fermentation. Through subsequent fermentation, a soy sauce product with improved flavor quality and reduced biogenic amine content is obtained.

[0007] Furthermore, the application involves adding *Tetracoccus dy-8* as an enhanced fermentation strain at the initial stage of soy sauce mash fermentation to improve the flavor and quality of the soy sauce. Specifically, this increases the content of key aroma and flavor compounds in the soy sauce, including but not limited to ethyl phenylacetate, isooctanol, and ethyl isovalerate.

[0008] A halophilic tetracoccus dy-8 that enhances flavor and reduces biogenic amine content ( Tetragenococcus halophilus (), deposited at the China General Microbiological Culture Collection Center, accession number CGMCC No. 7.713, deposited on March 17, 2026.

[0009] The application of the halophilic tetracoccus dy-8 in soy sauce brewing. This application enhances the flavor and reduces the content of biogenic amines during soy sauce fermentation, specifically by increasing the content of flavor compounds such as ethyl phenylacetate and reducing the content of biogenic amines such as 2-phenylethylamine in soy sauce.

[0010] Furthermore, the application method is to use halophilic tetracoccus dy-8 to ferment the soy sauce mash to obtain soy sauce.

[0011] The fermentation of the soy sauce mash using Halococcus tetragenus dy-8 includes the following steps: Steamed defatted soybeans and roasted wheat are mixed in a mass ratio of 1.5:1 to 1:1 to make koji and obtain koji material. The obtained koji material is mixed with brine with a salinity of 18% at a mass-volume ratio of 1:2 to obtain soy sauce mash. Inoculate the fermentation mash with 0.8%–1.2% of *Halophilic tetracoccus* dy-8, achieving a final inoculum concentration of 1×10⁻⁶. 7 CFU / g ~ 1×10 9 CFU / g, start fermentation, fermentation temperature 9℃~32℃.

[0012] Furthermore, the fermentation temperature is 9℃~15℃ for 15 days before fermentation.

[0013] Furthermore, starting from day 15 of fermentation, the fermentation temperature is 28℃~32℃.

[0014] Further fermentation for 115 to 125 days yields dy-8 soy sauce.

[0015] Further fermentation continues for 120 days to obtain dy-8 soy sauce.

[0016] Furthermore, the steamed defatted soybeans and roasted wheat are mixed at a mass ratio of 1.5:1.

[0017] Furthermore, the steamed defatted soybeans and roasted wheat are mixed in a 1:1 mass ratio.

[0018] Furthermore, the final inoculation concentration reached 1×10⁻⁶. 7 CFU / g.

[0019] Furthermore, the final inoculation concentration reached 1×10⁻⁶.9 CFU / g.

[0020] Furthermore, the fermentation temperature is 15°C for 15 days prior to fermentation.

[0021] Furthermore, fermentation begins on day 15 at a temperature of 28°C.

[0022] Furthermore, fermentation begins on day 15 at a temperature of 32°C.

[0023] Further fermentation continues for 115 days to obtain dy-8 soy sauce.

[0024] Further fermentation continues for 125 days to obtain dy-8 soy sauce.

[0025] Furthermore, the application involves adding Tetracoccus dy-8 as an enhanced fermentation strain during the fermentation stage of soy sauce mash to improve the flavor and quality of the soy sauce. Specifically, this results in a significant increase in the content of key aroma and flavor compounds in the soy sauce, including but not limited to ethyl phenylacetate, isooctanol, and ethyl isovalerate.

[0026] A microbial enhanced fermentation agent comprising the aforementioned halophilic tetracoccus dy-8.

[0027] The application of the halophilic tetracoccus dy-8 or the microbial enhanced starter in soy sauce fermentation.

[0028] The application is to enhance flavor and reduce biogenic amine content during soy sauce fermentation, increase the content of flavor substances such as ethyl phenylacetate, and reduce the content of 2-phenylethylamine in soy sauce.

[0029] Furthermore, the application involves using tetrad cocci dy-8 to reduce the content of biogenic amines in a soy sauce fermentation system.

[0030] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention provides a halophilic tetrad cocci dy-8 ( Tetragenococcus halophilus This strain is deposited at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 7.713 and deposit date of March 17, 2026. This strain can be used as an enhanced fermentation strain in the production of soy sauce or brewed sauces to improve product flavor and reduce some biogenic amine content.

[0031] (2) The tetrad cocci dy-8 provided by the present invention is isolated from soy sauce mash and belongs to the native beneficial microorganisms in the food brewing environment. It has good biocompatibility and application basis for soy sauce fermentation enhancement.

[0032] (3) The tetrad cocci dy-8 provided by the present invention was applied to the enhanced fermentation of soy sauce. After GC-O-MS and GC-MS analysis, it was found that the content of a variety of key aroma active substances in the obtained soy sauce was increased, which is beneficial to improving the soy sauce aroma, ester aroma and overall flavor coordination of soy sauce.

[0033] (4) The tetrad cocci dy-8 provided by this invention has the potential to reduce or regulate the accumulation of biogenic amines. After enhanced fermentation, the content of biogenic amines such as 2-phenylethylamine and tyramine in the finished soy sauce is reduced, which helps to improve the safety of the product for consumption. Attached Figure Description

[0034] Figure 1 Image of dy-8 morphology.

[0035] Figure 2 This is a phylogenetic tree. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto. Unless otherwise specified, the technical means used in the following embodiments are conventional means well known to those skilled in the art; the experimental methods used are all conventional methods; the materials, reagents, instruments, etc. used are all commercially available. The following contents need to be specifically explained:

[0037] Halophilic tetrad cocci dy-8, Latin name Tetragenococcus halophilus It is deposited at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 7.713 and deposit date of March 17, 2026, abbreviated as dy-8.

[0038] In the following embodiments, the koji making is carried out according to the conventional high-salt dilute soy sauce process in the art; the core of the present invention lies in the application of dy-8 in the initial inoculation of soy sauce mash fermentation, and the addition of other fermentation strains is not considered as an essential technical feature of the present invention.

[0039] MRS medium: 10g peptone, 5g beef extract, 4g yeast extract, 20g glucose, 1mL Tween-80, 2g dipotassium hydrogen phosphate, 5g sodium acetate, 2g triammonium citrate, 0.2g magnesium sulfate (MgSO4·7H2O), 0.05g manganese sulfate (MnSO4·4H2O), pH 6.2, sterilized at 121℃ for 20min.

[0040] Example 1: A method for producing soy sauce using Halophilic tetracoccus dy-8, comprising the following steps: S1. Defatted soybeans (soybean meal) are steamed and then mixed with roasted wheat at a mass ratio of 1.5:1 to make koji, thus obtaining koji material.

[0041] S2. Mix the koji material with brine with a salinity of 18% at a ratio of 1:2 (w / v) and transfer it to a fermentation tank.

[0042] S3. At the initial stage of fermentation of the soy sauce mash, inoculate the soy sauce mash with dy-8 at an inoculation rate of 1%, so that the final inoculation concentration reaches 1×10⁻⁶. 8 CFU / g; For the first 15 days of fermentation, the mash temperature was maintained at 9℃; for the next 15 days, the temperature was gradually increased to 28℃. Fermentation continued at 28℃ for 120 days, at which point fermentation ended; dy-8 soy sauce was obtained and designated as group T.

[0043] Comparative Example 1: A method for producing ordinary soy sauce, comprising the following steps: Defatted soybeans (soybean meal) are steamed and then mixed with roasted wheat in a specific ratio to make koji (fermentation starter). After koji making, the mixture is mixed with brine and transferred to a fermentation tank. For the first 15 days of fermentation, the mash temperature is maintained at 9°C. Over the next 15 days, the temperature is gradually increased to 28°C. Fermentation continues at 28°C for 120 days, after which the fermentation process is complete. The resulting product is ordinary soy sauce, designated as Group C.

[0044] Experiment 1: Isolation and purification of tetrad cocci A sample of fermented soy sauce mash was taken, and 2g of the mash sample was weighed and thoroughly shaken in 22.5mL of sterile aqueous solution to obtain a dilution of 10. -1 The diluted solution was serially diluted 10-fold to obtain 10 -2 10 -3 A series of gradient dilutions were prepared. 1 mL of each dilution was poured onto MRS agar plates containing 6% NaCl and incubated statically at 30°C for 5 days. Single colonies with different morphologies were picked, and the purification process was repeated three times. The purified strains were enriched with MRS broth containing 6% NaCl to obtain seed culture, which was then stored at 4°C for later use.

[0045] Strain screening: Strains isolated from the fermentation mash were inoculated into MRS broth containing 8% NaCl and cultured at 30°C for 48 hours, while pH was monitored to screen for strains that exhibited vigorous growth and rapid acidification. Next, to assess the aroma-producing potential of the selected strains, soybeans were pulverized and mixed with sterile 15% physiological saline at a ratio of 1:2 (w / v) to prepare a simulated fermentation medium, and cultured at 1×10⁻⁶... 6 The selected strain was inoculated into the culture medium at an initial concentration of CFU / mL, and then fermented at 30°C for 7 days. After fermentation, the culture medium was filtered, and volatile compounds were analyzed by GC-MS. Candidate strains were obtained.

[0046] Experiment 2 Identification of candidate strains Candidate strains were sequenced, and the sequences were BLAST-aligned with the NCBI GenBank database. The results showed that this strain was similar to... Tetragenococcus halophilus The homology is the highest, reaching 100%, such as... Figure 2 As shown. Based on morphological characteristics, this strain was identified as a tetrad coccus. Tetragenococcus halophilus It was named dy-8.

[0047] The candidate strains exhibited colonies that were round, milky white, smooth, and with regular edges. Gram staining was positive, and microscopic examination revealed the cells to be cocci, arranged singly, in pairs, or in tetrads. Figure 1 As shown.

[0048] Experiment 3: GC-O-MS detection of dy-8 soy sauce from Example 1 and ordinary soy sauce from Comparative Example 1 GC-O-MS results, as shown in Table 1, revealed a total of 42 volatile flavor compounds in the two sample groups, mainly including 9 alcohols, 4 acids, 13 esters, 7 aldehydes, 4 ketones, and 5 pyrazines. T-1, T-2, and T-3 represent three repeated measurements of aroma intensity in group T (the experimental group with added dy-8), while C-1, C-2, and C-3 represent three repeated measurements of aroma intensity in group C.

[0049] Table 1. GC-O-MS aroma intensity of volatile compounds during fermentation 1 5.55 Ethyl acetate 141-78-6 Fruity aroma 2 1 0 2 0 3 2 10.01 ethyl 2-methylbutyrate 7452-79-1 Apple and pineapple flavor 4 2 3 2 3 3 3 10.14 Ethyl hexanoate 123-66-0 Fruity aroma 0 0 0 0 0 0 4 14.76 n-Hexyl alcohol 111-27-3 Fruity aroma 3 3 3 0 0 0 5 16.09 Methyl tert-butyl ketone 75-97-8 mint scent 0 0 0 0 0 0 6 16.39 Ethyl lactate 97-64-3 Rich aroma 0 0 0 0 0 0 7 18.56 Octal 124-13-0 Fruity aroma 0 2 3 2 3 3 8 18.97 1-Heptene-3-one 2918-13-0 grassy aroma 3 3 4 0 0 0 9 20 Nononal 124-19-6 Citrus 3 0 3 0 0 3 10 20.08 Ethyl heptaate 106-30-9 Pineapple flavor 1 0 2 2 3 3 11 20.15 Diethyl succinate 123-25-1 Fruity aroma 0 0 3 0 0 0 12 20.74 furfural 98-01-1- astringent 4 4 4 0 0 0 13 21.22 4-Methoxyphenol 150-76-5 Caramel flavor 3 3 3 0 0 0 14 21.35 1-Hydroxy-2-Butanone 5077-67-8 Grain aroma 4 2 3 0 2 3 15 23.07 trans-2-octenal 2548-87-0 meaty aroma 4 3 3 2 0 2 16 23.28 Ethyl 3-methylthiopropionate 13327-56-5 Fruity aroma 2 2 0 3 0 0 17 23.34 Ethyl octanoate 106-32-1 Fruity aroma 3 3 4 1 0 1 18 23.51 2-Methylhexanoic acid 4536-23-6 sour 0 0 0 1 0 0 19 23.53 5-Methylfuranaldehyde 620-02-0 Spicy aroma 2 3 3 1 0 0 20 23.54 1-Octanol 111-87-5 grease smell 3 3 3 0 0 2 21 23.65 1-Octen-3-ol 3391-86-4 Mushroom aroma 4 3 0 2 0 3 22 23.92 Ethyl benzoate 93-89-0 Fruity aroma 3 3 0 0 0 0 23 24.34 3-Methyl-1-pentanol 589-35-5 Cocoa aroma 0 0 0 0 0 0 24 24.37 Guaiacol 90-05-1- Smoky 3 3 0 0 0 3 25 24.54 3-Methylvalerate 105-43-1 Scent of green grass 3 3 3 0 0 0 26 24.57 benzyl alcohol 100-51-6 Aroma 2 2 2 0 0 0 27 25.38 benzaldehyde 100-52-7 Floral fragrance 1 2 3 2 2 1 28 26.12 Undecanoic acid 112-37-8 sour 3 3 0 0 0 0 29 26.22 2,4-Dimethylbenzaldehyde 15764-16-6 sweet 0 2 2 0 0 0 30 26.23 3-Methyl-1-butanol 123-51-3 mellow aroma 0 1 0 0 0 0 31 26.48 Ethyl lauryl ester 106-33-2 Fruity aroma 3 0 3 0 0 0 32 27.74 2-Hepagonal 110-43-0 Nut flavor 0 3 0 0 0 0 33 28.02 phenylacetaldehyde 122-78-1 Floral fragrance 4 3 3 3 3 3 34 28.33 furfuryl alcohol 98-00-0 Caramel aroma 2 3 2 1 0 3 35 28.73 2,6-Dimethylpyrazine 108-50-9 Nutty aroma 2 2 2 0 3 1 36 29.15 Ethyl decanoate 110-38-3 Fruity aroma 0 0 0 0 0 0 37 29.18 Methyl palmitate 112-39-0 Durian aroma 3 3 3 0 0 0 38 29.20 2-Ethyl-5-methylpyrazine 13360-64-0 roasted aroma 4 4 4 0 0 0 39 29.61 3-Methylthiopropanol 505-10-2 Sauce flavor 3 3 0 2 2 0 40 31.21 Ethyl phenylacetate 101-97-3 Rose fragrance 0 2 2 0 0 0 41 31.47 Phenylacetyl acetate 103-45-7 The aroma of honey 3 3 3 1 1 0 42 31.50 hexanoic acid 142-62-1 Yeast flavor 0 0 0 0 0 0 43 32.23 Eugenol 97-53-0 Spicy flavor 0 3 3 0 0 0 44 32.53 3-Methylbutyric acid 503-74-2 body odor 3 2 2 0 2 1 45 33.09 Ethyl 3-phenylpropionate 2021-28-5 sweet 0 0 0 0 0 3 46 33.10 2-Acetylpyrrole 1072-83-9 nut 0 0 3 0 0 0 47 33.16 Phenylacetyl alcohol 60-12-8- Rose fragrance 4 2 3 2 2 2 48 34.15 2,3-Dimethylpyrazine 5910-89-4 Baking flavor 3 3 3 0 0 0 49 34.16 4-Ethylphenol 123-07-9 sweet 0 3 2 0 0 1 50 34.38 coconut aldehyde 104-61-0 Peach Blossom Fragrance 3 3 2 3 0 0 51 35.12 4-Ethylguaiacol 2785-89-9 Smoky smell 4 3 3 3 2 2 52 35.34 Isooctyl alcohol 104-76-7 sweet aroma 2 0 2 0 0 0 53 36.05 Ethyl myristate 124-06-1 Fruity aroma 0 3 3 0 0 0 54 36.85 Ethyl palmitate 628-97-7 Creamy aroma 0 2 2 0 0 0 55 37.25 Ethyl isovalerate 108-64-5 Banana flavor 4 4 4 0 3 0 56 37.25 2-Ethylphenol 90-00-6 Baking aroma 0 0 3 0 0 0 57 37.47 p-Vinylguaiacol 7786-61-0 Spicy aroma 0 0 0 0 0 0 58 37.54 Ethyl linoleate 544-35-4 Fruity aroma 0 0 0 0 0 0 59 38.33 2,3,5-Trimethylpyrazine 14667-55-1 Nut flavor 0 0 0 0 0 4 60 41.14 Ethyl stearate 111-61-5 Wax fragrance 0 0 0 2 0 0 61 44.53 1-Butanol 71-36-3 mellow flavor 0 0 0 0 0 0 From a compositional perspective, both groups T and C primarily contain alcohols and esters as flavor components, but there are significant differences in the relative content of various substances between the two groups. The peak intensities of most alcohols in group T are higher than those in group C. The intensity of higher alcohols such as 3-methyl-1-butanol or isoamyl alcohol, and phenylethyl alcohol is particularly significant; these substances are important contributors to the soy sauce aroma and floral / fruity aroma. Compared to group C, aldehydes such as phenylacetaldehyde, trans-2-octenal, and furfural are more intense in group T; these substances are important components of the soy sauce aroma and caramel aroma. Furthermore, the overall intensity of phenolic substances is also higher in group T than in group C. Pyrazines such as 2-ethyl-5-methylpyrazine and 2,3-dimethylpyrazine, as well as ketones such as 1-hepten-3-one, are all more intense in group T than in group C; these substances make significant contributions to the roasted and caramel aroma of soy sauce. The above results indicate that enhanced fermentation by strain dy-8 can significantly alter the composition of volatile flavor compounds in soy sauce, increase the content of various key aroma compounds, and thus endow soy sauce with a richer and more harmonious soy sauce and ester aroma flavor.

[0050] Experiment 4: Detection of dy-8 biogenic amines in Example 1 soy sauce and biogenic amines in Comparative Example 1 ordinary soy sauce. After 4 months of fermentation, the biogenic amines of dy-8 soy sauce in Example 1 and ordinary soy sauce in Comparative Example 1 were tested according to the national standard GB / T5009.208-2016. The main tests were conducted on the content of 7 biogenic amines in the samples: 2-phenylethylamine, putrescine, cadaverine, histamine, tyramine, spermidine, and spermine.

[0051] The results of biogenic amine detection are shown in Table 2. Putrescine, cadaverine, histamine, and spermine were not detected in either group of samples, and the detection limits met the national standards.

[0052] Table 2. Endpoint biogenic amine content of fermented soy sauce Note: Different letters in the same row indicate significant differences (P<0.05), and only the detected samples are compared; ND, not detected.

[0053] Among the detected biogenic amines, the contents of 2-phenylethylamine and tyramine showed significant differences between the two groups. Specifically, the contents of both 2-phenylethylamine and tyramine in group T (the experimental group) were significantly lower than those in the control group (group C). This result indicates that inoculating the soy sauce mash fermentation system with tetrad cocci dy-8 can effectively inhibit or reduce the formation or accumulation of these two major biogenic amines. In summary, strain dy-8 not only enhances the flavor quality of soy sauce but also exhibits excellent biogenic amine reduction capabilities, demonstrating that this strain possesses dual functions of aroma production and amine reduction, and has significant technical advantages when applied to the fortified fermentation of soy sauce.

[0054] Experiment 5: Detection of dy-8 soy sauce flavor compounds in Example 1 and ordinary soy sauce flavor compounds in Comparative Example 1 To further evaluate the effect of halophilic tetracoccus dy-8 on the composition of volatile flavor compounds in soy sauce, GC-MS was used to detect volatile compounds in the dy-8 fortified fermented soy sauce obtained in Example 1 and the ordinary soy sauce obtained in Comparative Example 1. The results are shown in Tables 3 to 18. " / " in the tables indicates that the item was not present.

[0055] Table 3. Content of volatile flavor compounds during fermentation Table 4. Content of volatile flavor compounds during fermentation (II) Table 5. Content of volatile flavor compounds during fermentation (Part 3) Table 6. Content of volatile flavor compounds during fermentation (Part 4) Table 7. Content of volatile flavor compounds during fermentation (V) Table 8. Content of volatile flavor compounds during fermentation (VI) Table 9. Content of volatile flavor compounds during fermentation (Part 7) Table 10 Content of volatile flavor compounds during fermentation Table 11 Content of volatile flavor compounds during fermentation (IX) Table 12 Content of volatile flavor compounds during fermentation Table 13 Content of volatile flavor compounds during fermentation (XI) Table 14 Content of volatile flavor compounds during fermentation (12) Table 15 Content of Volatile Flavor Compounds During Fermentation (XIII) Table 16 Content of Volatile Flavor Compounds During Fermentation (XIV) Table 17 Content of volatile flavor compounds during fermentation (15) Table 18 Content of Volatile Flavor Compounds During Fermentation (XVI) From the perspectives of acids, esters, aldehydes, ketones, phenols, and pyrazines, dy-8 enhanced fermentation significantly promoted the generation and accumulation of various flavor compounds. Compared with ordinary soy sauce, the dy-8 group had higher contents of key flavor compounds such as ethyl lactate, phenylacetaldehyde, 1-octen-3-one, and 2-methoxy-4-vinylphenol, with average contents of 333.45 μg / kg, 3604.83 μg / kg, 56.10 μg / kg, and 334.75 μg / kg, respectively, which were higher than those in ordinary soy sauce (153.25 μg / kg, 2879.09 μg / kg, 19.87 μg / kg, and 179.38 μg / kg). Meanwhile, the dy-8 group also detected flavor compounds not found in ordinary soy sauce, such as ethyl acetate, diethyl succinate, ethyl 2-methylbutyrate, 2-phenyl-2-butenal, theobromaldehyde, 2-methoxy-5-vinylphenol, 2,3-dimethylpyrazine, and 2-ethyl-6-methylpyrazine. These compounds are associated with flavor characteristics such as fruity, sweet, floral, caramel, phenolic, roasted, and soy sauce aromas, indicating that dy-8 can promote the formation of multiple key aroma compounds, thereby enhancing the ester, caramel, and roasted aroma characteristics of soy sauce and making the soy sauce flavor richer and more harmonious. In summary, the application of halophilic tetracoccus dy-8 to the enhanced fermentation of soy sauce not only increases the content of some existing flavor compounds but also promotes the formation of multiple flavor compounds not detected in ordinary soy sauce. The above results show that dy-8 has a significant promoting effect on the formation of volatile flavor compounds in soy sauce, effectively improving the aroma profile of soy sauce, enriching the flavor layers of the product, and significantly improving the overall flavor quality of soy sauce.

[0056] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A halophilic tetracoccus dy-8 that enhances flavor and reduces biogenic amine content ( Tetragenococcus halophilus ), characterized in that, It is deposited at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 7.713 and deposit date of March 17, 2026.

2. The application of the halophilic tetracoccus dy-8 as described in claim 1 in soy sauce brewing.

3. The application according to claim 2, characterized in that, The method of application is as follows: use halophilic tetracoccus dy-8 to ferment the soy sauce mash to obtain soy sauce.

4. The application according to claim 3, characterized in that, The fermentation of the soy sauce mash using Halococcus tetragenus dy-8 includes the following steps: Steamed defatted soybeans and roasted wheat are mixed in a mass ratio of 1.5:1 to 1:1 to make koji and obtain koji material. The obtained koji material is mixed with brine with a salinity of 18% at a mass-volume ratio of 1:2 to obtain soy sauce mash. Inoculate the fermentation mash with 0.8%–1.2% of *Hydroxytetracoccus dy-8*, achieving a final inoculum concentration of 1×10⁻⁶. 7 CFU / g ~ 1×10 9 CFU / g, start fermentation, fermentation temperature 9℃~32℃.

5. The application according to claim 4, characterized in that, The fermentation temperature is 9℃~15℃ for 15 days before fermentation.

6. The application according to claim 4, characterized in that, It also includes starting on the 15th day of fermentation, with a fermentation temperature of 28℃~32℃.

7. The application according to claim 4, characterized in that, It also includes fermenting for 115 to 125 days to obtain dy-8 soy sauce.

8. The application according to claim 7, characterized in that, It also includes fermenting for 120 days to obtain dy-8 soy sauce.

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