Coxakella cocori BSX-h4 strain and application thereof

Abstract

The invention discloses a coxakella cocori BSX-h4 strain and an application of the coxakella cocori BSX-h4 strain. According to the present invention, the Kosakia coffei BSX-h4 strain is preserved in Guangdong Province Microbial Culture Collection Center, the preservation date is January 8, 2024, and the preservation number is GDMCC No: 64253. The invention further provides a preparation method of the Kosakia coffei BSX-h4 strain, when the BSX-h4 strain is used for fermentation treatment of coffee, the coffee fermentation process can be stabilized, the problems of uneven coffee bean quality and poor production batch stability can be solved, the variety and content of flavor substances such as alcohols, ketones, aldehydes, pyrazines and ethers in raw coffee beans and baked coffee beans can be obviously increased, and the coffee quality can be improved. In addition, the bacterial strain has food safety, and can be developed into a coffee aroma enhancement microbial fermentation agent for improving the flavor of coffee and improving the quality of coffee.

Description

Technical Field

[0001] The present invention belongs to the technical field of coffee fermentation, and more specifically, relates to a Kosakonia cowanii BSX-h4 strain and application thereof. Background Art

[0002] Coffee beans refer to the fruits of the beverage crop coffee (Coffea) of the Rubiaceae family. After peeling and fermentation, green coffee beans can be obtained. After roasting, the green coffee beans can be used to make roasted coffee drinks.

[0003] During the primary processing of green coffee beans, microbial fermentation can convert sugars in coffee fruits into aromatic precursors such as alcohols, acids, ketones and aldehydes, giving green coffee beans a unique flavor. For example, furfuryl alcohol is the main source of coffee aroma, with a pleasant roasted and smoky aroma; trans-nonanal gives coffee a fresh woody aroma; cycloolefins and alkaline cyclopentanedione give coffee a caramel aroma; maltol and 3-methylbutanal give coffee a sweet taste; furan derivatives can give coffee fruity aromas such as pineapple and mango. The flavor of commercially available roasted beans (commodity beans) is mainly affected by the volatile mixture formed by the aromatic precursors in the green beans during the roasting process. It is an extremely important sensory attribute of roasted beans and determines the price of roasted beans.

[0004] At present, the primary processing of small-grain coffee in my country is mainly based on traditional wet fermentation. This fermentation process is greatly affected by the type of microorganisms and temperature, which can easily cause problems such as uneven quality of coffee beans and poor stability of production batches. Developing microbial fermentation agents and stabilizing the microbial composition in wet processing play an important role in the formation of coffee flavor, quality and economic benefits. Although there are reports of fermentation strains that can be used to reduce the bitterness of coffee, the types and contents of flavor substances such as alcohols, acids and ketones enriched in coffee beans after fermentation by different types of microorganisms are significantly different, and coffee flavors are diverse. Continuously exploring fermentation strains that can enhance the different flavors of coffee is conducive to the development of coffee products with different flavors and the long-term development of the coffee industry. Summary of the invention

[0005] In view of the above-mentioned technical problems, the present invention provides a strain of Cossackia coli, which can be used to ferment coffee beans to increase the content of flavor substances such as alcohols and esters in the fermented coffee beans, thereby improving the flavor of coffee.

[0006] The first object of the present invention is to provide a strain of Coxsackieae.

[0007] The second object of the present invention is to provide a bacterial agent containing the strain.

[0008] The third object of the present invention is to provide the use of the strain or the bacterial agent in fermenting coffee beans.

[0009] The fourth object of the present invention is to provide the use of the strain or the bacterial agent in preparing a preparation for fermenting coffee beans.

[0010] A fifth object of the present invention is to provide use of the strain or the bacterial agent in improving the flavor of coffee.

[0011] A sixth object of the present invention is to provide use of the strain or the bacterial agent in preparing a preparation for improving the flavor of coffee.

[0012] A seventh object of the present invention is to provide a fermented coffee.

[0013] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0014] The present invention obtains a Kosakonia cowanii strain that can be used for coffee bean fermentation through separation and purification, and is named as the BSX-h4 strain. The strain can not only stabilize the coffee fermentation process, improve the problems of uneven coffee bean quality and poor stability of production batches, but also increase the types and contents of flavor substances such as alcohols, ketones, aldehydes, pyrazines and ethers in the fermented coffee beans and roasted beans, improve the floral and fruity flavor of the coffee beverage, and improve the coffee flavor. In addition, the coffee beans and roasted beans obtained by fermentation using the strain do not contain sulfides. Therefore, the present invention requests protection for the BSX-h4 strain and its application.

[0015] Specifically, the BSX-h4 strain of Coxsackievirus cohnii was deposited in the Guangdong Provincial Microbiological Culture Collection Center on January 8, 2024, with the deposit number GDMCC No: 64253.

[0016] The invention also provides a bacterial agent containing the strain.

[0017] The strain or bacterial agent of the present invention can be used to ferment coffee beans, stabilize the coffee fermentation process, and increase the content of flavor substances in the fermented coffee beans and the roasted beans obtained by subsequent roasting. Therefore, the present invention claims protection for the use of the strain or bacterial agent in fermenting coffee beans.

[0018] The present invention also claims to protect the use of the strain or the bacterial agent in preparing a preparation for fermenting coffee beans.

[0019] The present invention also claims to protect the use of the strain or the bacterial agent in improving the flavor of coffee.

[0020] The present invention also seeks to protect the use of the strain or the bacterial agent in the claims in preparing a preparation for improving the flavor of coffee.

[0021] Specifically, the improvement of coffee flavor is to increase the content of flavor substances in coffee beans.

[0022] Specifically, increasing the content of flavor substances in coffee beans includes increasing the content of substances that were originally undetectable to a detectable level.

[0023] Specifically, the coffee beans include green coffee beans and roasted coffee beans.

[0024] Specifically, the flavor substances include decanal, 5-methylfurfural, hexyl acetate, propyl caproate and / or furanone, which are characteristic aroma components that add floral and fruity aroma to coffee. Among the flavor substances, decanal has a strong floral and fruity aroma, which is sometimes compared to the aroma of orange blossom or jasmine and the aroma of citrus fruits. It is widely used in the manufacture of perfumes and flavors to provide floral and fruity aromas for products. 5-Methylfurfural brings a sweet, caramel-like characteristic flavor of coffee. Hexyl acetate has an aroma similar to that of ripe apples or pears. Propyl caproate has an aroma similar to that of apples, pears or bananas with a slight smell of fat or cheese. Furanone has a strong fruity aroma and jam flavor, and has a raspberry aroma after dilution.

[0025] Specifically, the coffee is coffee beans.

[0026] The present invention also provides a fermented coffee, which is prepared by using coffee beans in which the strain or the bacterial agent of the present invention is used during the fermentation process.

[0027] Specifically, the content of flavor substances in the coffee is increased, and the flavor substances include decanal, 5-methylfurfural, hexyl acetate, propyl hexanoate and / or furanone.

[0028] The present invention has the following beneficial effects:

[0029] The present invention provides a Kosakonia cowanii strain, named as BSX-h4 strain, which is deposited in Guangdong Microbiological Culture Collection Center on January 8, 2024, and the deposit number is GDMCC No: 64253. The BSX-h4 strain of the present invention is used to ferment coffee, which can not only stabilize the coffee fermentation process, improve the problems of uneven coffee bean quality and poor stability of production batches, but also significantly increase the content of flavor substances such as alcohols, ketones, aldehydes, pyrazines and ethers in green coffee beans and roasted coffee beans, and improve the floral and fruity flavor of the coffee beverage produced. The strain has food safety and can be developed into a coffee aroma microbial fermentation agent to improve the coffee flavor and improve the coffee quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Figure 2 is the colony morphology of the BSX-h4 strain; Figure a is a plate of the BSX-h4 strain inoculated with streaks; Figure b is a single colony of the BSX-h4 strain.

[0031] Figure 2 The Gram staining results of BSX-h4 strain.

[0032] Figure 3 This is a phylogenetic tree constructed based on the 16S rDNA sequence and gyrB sequence of the BSX-h4 strain.

[0033] Figure 4 The statistical results of the types of volatile substances unique to and common in the coffee beans of the natural fermentation group (CK) and the strain fermentation group (H4).

[0034] Figure 5 The statistical results of the types of volatile substances unique to and common in the roasted beans of the natural fermentation group (CK) and the strain fermentation group (H4). DETAILED DESCRIPTION

[0035] The present invention is further described below in conjunction with the accompanying drawings and specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0036] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0037] The BSX-h4 strain described in the embodiment of the present invention is the Kosakonia cowanii BSX-h4 strain, which was deposited in the Guangdong Provincial Microbiological Culture Collection Center on January 8, 2024, with a deposit number of GDMCC No: 64253, and the deposit address is 5th Floor, Compound Experimental Building, No. 100 Xianlie Middle Road, Yuexiu District, Guangzhou City, Guangdong Province.

[0038] Example 1 Acquisition and identification of BSX-h4 strain

[0039] 1. Acquisition of BSX-h4 strain

[0040] The BSX-h4 strain of the present invention is separated and purified from the fermentation broth of Coffea arabica L. by using the plate dilution method. The specific process is as follows:

[0041] The fermentation liquid of small-grain coffee was filtered through six layers of gauze, and the filtrate was diluted in a gradient manner (10 -1 , 10 -2 , 10-3 , 10 -4 and 10 -5 ), 100 μL of the diluted filtrate of different concentrations were respectively applied to LB liquid culture medium, and 3 replicates were set for each gradient; cultured at 37°C, single colonies grown were picked and streaked and inoculated into LB solid culture medium; the isolated strains were purified and cultured, and after continuous purification for 3 times, they were preserved by glycerol freezing method.

[0042] 2. Identification of BSX-h4 strain

[0043] (1) Morphological identification

[0044] The BSX-h4 strain was streaked onto LB solid medium and cultured at 37°C for 48 hours before observing the morphology of single colonies. In addition, a single colony of the BSX-h4 strain was inoculated into LB liquid medium and cultured at 37°C and 150 r / min for 16 to 24 hours. An appropriate amount of bacterial liquid was taken for Gram staining and its Gram staining characteristics were observed under a microscope.

[0045] The colony morphology of the BSX-h4 strain is as follows Figure 1 As shown; Figure 1 a in the figure is a plate of BSX-h4 strain inoculated by streaking; Figure 1 b in the figure is a single colony of the BSX-h4 strain. Figure 1 It can be seen that the colonies of the BSX-h4 strain are round, yellow, with smooth edges, moist and opaque surfaces, and convex in the middle.

[0046] The Gram staining results of BSX-h4 strain are as follows Figure 2 As shown. Figure 2 It can be seen that the BSX-h4 strain is a Gram-negative bacterium with a rod-shaped body and a body size of 0.5-0.8 μm×4.0-6.0 μm.

[0047] (2) Molecular Biological Identification

[0048] The BSX-h4 strain was activated in LB solid culture medium, cultured at 37°C for 48 hours, and then a single colony was picked and inoculated into LB liquid culture medium, and cultured at 37°C and 150 r / min for 12 hours; the bacteria were collected by centrifugation and the genomic DNA of the BSX-h4 strain was extracted according to the instructions of the OMEGA bacterial DNA extraction kit; the extracted genomic DNA of the strain was used as a template, and PCR amplification was performed using 16S rRNA primers and gyrB primers respectively; the amplified products were detected by electrophoresis and sent to a sequencing company for sequencing.

[0049] The nucleotide sequence of the 16S rRNA primer is as follows:

[0050] 27F: 5'-AGAGTTTGATCCTGGCTCAG-3';

[0051] 1492R: 5'-GGTTACCTTGTTACGACTT-3'.

[0052] The nucleotide sequence of the gyrB primer is as follows:

[0053] F: 5'-TTGGTGCTTCTGTTGTT-3';

[0054] R: 5′-CATCCCCAAAGCCAG-3′.

[0055] The PCR reaction system (25 μL in total) was: 2×PCR Buffer 12.5 μL, 2 mM dNTPs 5 μL, 10 pmoL / mL upstream primer 0.75 μL, 10 pmoL / mL downstream primer 0.75 μL, KOD FX (1.0 U / μL) 0.5 μL, DNA 1.0 μL, ddH2O to make up to 25 μL. The PCR amplification program was: 94°C pre-denaturation for 5 min, 98°C denaturation for 10 s, 55°C annealing for 30 s, 72°C extension for 30 s, a total of 35 cycles, and finally 72°C extension for 5 min.

[0056] From the sequencing results, it can be seen that the 16S rDNA sequence of the BSX-h4 strain is shown in SEQ ID NO.1, and its gyrB sequence is shown in SEQ ID NO.2.

[0057] The sequencing results of the 16S rDNA sequence and gyrB sequence of the BSX-h4 strain were compared with the 16S rDNA and gyrB sequences of existing strains in the NCBI database by BLAST comparison and analysis. It was found that the similarity between the 16S rDNA sequence and gyrB sequence of the BSX-h4 strain and multiple Kosakonia cowanii strains was more than 98%. Based on the 16S rDNA sequence and gyrB sequence of the BSX-h4 strain, the MEGA 11 software was used to construct a phylogenetic tree using the Neighbour-joining method, as shown in the figure. Figure 3 As shown. Figure 3 It can be seen that the BSX-h4 strain is most closely related to the reported Cossackia corynae. Combining the morphological and molecular biological identification results of the BSX-h4 strain, the BSX-h4 strain was identified as Cossackia corynae.

[0058] Example 2: Food safety test of BSX-h4 strain

[0059] The present invention tested the edible safety of the BSX-h4 strain according to "GB 15193.3-2014 National Food Safety Standard Acute Oral Toxicity Test". 20 male and female ICR mice with a body weight range of 18 to 22 g were selected and raised in 8 cages, with 5 female mice or 5 male mice in each cage. After acclimation for 2 days in the ABSL-2 breeding area of ​​the Yunnan University Experimental Animal Center (20°C to 26°C, relative humidity 40% to 70%), gavage tests were performed. The mice were fasted for 4 hours before the test. After being given the BSX-h4 bacterial suspension, the mice needed to continue fasting for 1 hour, with free drinking water during the fasting period. The BSX-h4 strain (OD 600 =3.0) rinsed twice with sterile water and resuspended for use. The intragastric doses for mice were 0, 5, 10, and 15 g / kg, and the intragastric volume was 30 mL / kg. All mice were observed for 7 consecutive days after intragastric administration, and the number of deaths of mice was recorded.

[0060] The results of the food safety test of the BSX-h4 strain are shown in Table 1. As shown in Table 1, during the 7-day observation period after the mice were gavaged, no death or poisoning occurred in the mice, and the mice were active during the test period, indicating that the BSX-h4 strain is safe and non-toxic.

[0061] Table 1 Death of mice under different oral doses

[0062]

[0063] Example 3 Effect of BSX-h4 strain fermentation treatment on the volatile substance content of green coffee beans and roasted coffee beans

[0064] 1. Fermentation and roasting of coffee beans

[0065] The fermentation treatment of coffee beans is divided into two groups, namely the natural fermentation group (CK) and the strain fermentation group (H4); both fermentation treatment systems retain the microorganisms naturally carried by coffee beans, and the system contains microbial strains from natural sources such as peels, pulp, and picking environments. The only difference between the strain fermentation group and the natural fermentation group is that the strain fermentation group is artificially inoculated with 1% (v / v) of the BSX-h4 strain activation liquid in the fermentation system (the final concentration of the bacteria is 5.0log CFU / mL).

[0066] The specific process is as follows: the coffee berries harvested at the same location were mechanically peeled, 2.0 kg of peeled coffee beans were placed in an 8.0 L glass fermentation tank, and 4.0 L of deionized water was added. 1% (v / v) of the BSX-h4 strain activation solution was added to the H4 fermentation group, and the same amount of deionized water was added to the control group. The coffee bean fermentation system of each group was placed in a 30°C constant temperature incubator for 60 hours. Three replicates were set for each group.

[0067] After the fermentation treatment, each group of coffee beans was placed in a cool environment to dry naturally, and the coffee bean shells and silver skins were removed by a coffee shelling machine to obtain coffee beans, which were stored in a sealed environment at room temperature; each group of coffee beans obtained after the fermentation treatment was roasted under the same conditions. Roasting conditions: 20g of coffee beans were roasted each time, using a coffee bean roaster, the bean temperature was 160℃, and dehydration began when the temperature rose to 180℃. After dehydration for 10 minutes, the temperature was adjusted to the roasting temperature of 220℃ for roasting, and the roasting time was 10 minutes.

[0068] 2. Detection of volatile substances in green and roasted coffee beans

[0069] The present invention uses gas chromatography-mass spectrometry (GC-MS) technology to detect and analyze volatile substances contained in green coffee beans and roasted coffee beans of a natural fermentation group and a strain fermentation group.

[0070] The specific process is as follows: grind the green coffee beans and roasted beans obtained after each group of fermentation treatment into powder and pass through a 20-mesh sieve for later use; accurately weigh 6g of the prepared green coffee beans and roasted beans into a 100mL blue-capped bottle, add 50mL of ethyl acetate (boiling point 76.5-77.5°C), place it in an ultrasonic constant temperature water bath oscillator for extraction for 1h, and then stand for 20-30min to allow it to separate, absorb the upper layer and filter it twice with qualitative filter paper, transfer the filtrate to a rotating bottle and evaporate it on a rotary evaporator to completely remove the ethyl acetate, remove the rotating bottle after rotating until no liquid drops, add 2mL of chromatographic grade dichloromethane and mix it with the coffee oil in the bottle, use a 1mL syringe to filter the mixed solution through a 0.22μm needle filter membrane into an injection bottle, and place it in a GC-MS instrument for detection of volatile substances.

[0071] Microextraction conditions: solid phase microextraction head (SUPELCO): 50 / 30μm PDMS / DVB / CAR, Stableflex; extraction head aging temperature: 250℃, aging time: 300s, insertion depth: 20mm, coating extension length: 12mm; the sample was placed in a 20mL headspace bottle for preheating, heating temperature: 40℃, extraction temperature: 60℃, extraction time: 2400s, insertion depth: 15mm, coating extension length: 12mm, stirring speed: 300r / min, stirring time: 600s, decomposition temperature: 270℃, decomposition time: 300s, insertion depth: 20mm, coating extension length: 12mm.

[0072] Gas chromatography conditions: chromatographic column: Agilent 19091s-433HP-5MS (30m×0.25mm×0.25μm); column temperature: temperature program, 40°C for 5 min, then 2°C / min to 70°C, hold for 2 min, 3°C / min to 120°C, then 5°C / min to 50°C, and finally 10°C / min to 230°C, hold for 2 min, flow rate 1.4mL / min. Detector: MSD detector; carrier gas He (purity 99.999%), 40mL / min; split injection: split ratio 5:1; septum purge flow rate 3mL / min; injection port temperature: 270°C.

[0073] Mass spectrometry conditions: ion source: EI source, electron energy 70 eV; ion source temperature: 230°C; quadrupole temperature is 150°C; transfer line temperature: 280°C; acquisition mode: scanning mode Scan / SIM; scanning mass range: 35-550; solvent delay 1.0 min.

[0074] 3. Analysis results of volatile substances

[0075] (1) Analysis results of volatile substances in green coffee beans

[0076] The volatile substances of the two groups of coffee beans after fermentation were analyzed by combining the GC-MS built-in spectral library and the NIST spectral library. 68 compounds were detected in the samples of the CK and H4 groups, which were divided into alcohols, esters, acids, ketones, aldehydes, pyrazines, furans, pyrroles and other substances, a total of 9 categories, as shown in Table 2. As can be seen from Table 2, after inoculation of the BSX-h4 strain for fermentation, the relative content of alcohols, esters, acids, ketones, aldehydes, pyrazines, furans, and pyrroles in the obtained coffee beans increased. Based on the GC-MS analysis results, the present invention counted the types of volatile substances unique and common to the coffee beans in the CK and H4 groups, and the results are as follows: Figure 4 As shown. Figure 4 It can be seen that in terms of specific component types, 41 and 53 substances were detected in the CK and H4 groups, respectively, of which 15 were unique to CK, 27 were unique to H4, and 26 were shared by both.

[0077] Table 2 Composition analysis of volatile substances in CK and H4 coffee beans

[0078]

[0079]

[0080]

[0081] nd in the table means not detected.

[0082] (2) Analysis results of volatile substances in roasted beans

[0083] Similar to the above, the volatile substances of the two groups of roasted beans after fermentation and roasting were analyzed in combination with the GC-MS built-in spectral library and the NIST spectral library. The volatile substances detected in the CK and H4 group samples are specifically shown in Table 3. As can be seen from Table 3, a total of 104 volatile compounds were identified in the two groups of samples, including alcohols, esters, ethers, acids, phenols, ketones, aldehydes, pyrazines, pyrroles, furans and other substances, a total of 11 categories. Compared with the natural fermentation group, the number of alcohols, phenols, ketones, aldehydes, pyrroles and pyrazines in the fermentation group inoculated with the BSX-h4 strain increased, and ether substances were also added. Based on the GC-MS analysis results, the present invention counted the types of volatile substances unique and common to the roasted beans in the CK and H4 groups, and the results are as follows. Figure 5 As shown in the figure, 57 and 75 substances were detected in CK and H4, respectively, of which 28 were unique to CK, 46 were unique to H4, and 29 substances were common to both. Figure 5 ).

[0084] Table 3 Composition analysis of volatile substances in roasted beans of groups CK and H4

[0085]

[0086]

[0087]

[0088]

[0089] nd in the table means not detected.

[0090] After testing, the composition analysis results of volatile substances in each replicate group were not much different, indicating that the use of the BSX-h4 strain described in the present invention to ferment coffee can stabilize the coffee fermentation process and improve the problems of uneven coffee bean quality and poor stability of production batches.

[0091] Example 4 Evaluation of coffee characteristic aroma

[0092] In addition to detecting and analyzing the volatile substances in green coffee beans and roasted beans, the present invention also cupped the roasted beans of the natural fermentation group and the strain fermentation group with reference to the cupping system of the Specialty Coffee Association of America (SCAA), and evaluated the characteristic aroma of coffee. The specific process is: accurately weigh 8.50g of freshly ground coffee powder in the cupping, inject 150mL of 93°C hot water, and form an evaluation team composed of 4 Q-Grader international coffee quality tasters to score the dry and wet aroma, flavor, aftertaste value, acidity, mellowness, balance, consistency, cleanliness, sweetness and overall evaluation of the coffee, a total of 10 indicators, of which the consistency, cleanliness and sweetness indicators are given full marks. The sum of the scores of all 10 sensory indicators is the final score of a single sample, and the brewed coffee liquid is described in terms of sensory smell at the same time.

[0093] The evaluation results of the characteristic coffee aroma of the roasted beans in the CK and H4 groups are shown in Table 4. As shown in Table 4, the total scores of the uninoculated and inoculated roasted beans are 81.5 and 82.5, respectively; among them, the inoculated roasted beans have improved in aftertaste, acidity, mellowness and balance compared with the uninoculated roasted beans.

[0094] Table 4 Evaluation results of coffee characteristic aroma of roasted beans in groups CK and H4

[0095]

[0096] The sensory descriptions of the characteristic coffee aroma of the roasted beans in groups CK and H4 are shown in Table 5.

[0097] Table 5 Sensory description of coffee aroma characteristics of roasted beans in groups CK and H4

[0098]

[0099] As shown in Table 5, compared with the natural fermentation group, the inoculated fermentation group has a richer fruity aroma, and a new floral aroma is also added. Combined with the volatile substance analysis results of Example 3, the newly added fruity aroma in the inoculated roasted beans is related to ester substances. Hexyl acetate is usually described as fruity, especially similar to the aroma of ripe apples or pears. Propyl caproate also has a special fruity aroma, especially similar to the aroma of apples, pears or bananas with a slight smell of fat or cheese. The content of propyl caproate in the H4 group roasted beans is relatively higher, which is one of the reasons why the H4 roasted beans have a richer fruity aroma. In addition, furanone has a strong fruity aroma and jam flavor, and has a raspberry aroma after dilution. The newly added floral aroma in the H4 roasted beans is related to decanal, which has a strong floral and fruity aroma, sometimes compared to the aroma of orange blossom or jasmine and the aroma of citrus fruits (especially oranges and lemons). Decanal also exists in many plants in nature, especially in the essential oils of flowers and citrus fruits. Therefore, it is widely used in the manufacture of perfumes and flavors to provide products with floral and fruity aromas. 5-Methylfurfural in aldehydes brings a sweet, caramel-like characteristic flavor of coffee. Ketones are mostly nutty and caramel-flavored. The newly added ketones in the inoculated fermentation group make the coffee as a whole present a mellow coffee aroma mixed with the aroma of fruit, making the main aroma of coffee more refreshing and balanced.

[0100] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A strain of Kosakonia cowanii, characterized in that The strain was deposited in Guangdong Provincial Microbiological Culture Collection Center on January 8, 2024, with the deposit number GDMCC No: 64253.

2. A bacterial agent containing the strain according to claim 1.

3. Use of the strain according to claim 1 or the bacterial agent according to claim 2 in fermenting coffee beans.

4. Use of the strain according to claim 1 or the bacterial agent according to claim 2 in preparing a preparation for fermenting coffee beans.

5. Use of the strain according to claim 1 or the bacterial agent according to claim 2 in improving the flavor of coffee.

6. Use of the strain according to claim 1 or the bacterial agent according to claim 2 in the preparation of a preparation for improving the flavor of coffee.

7. The use according to claim 5 or 6, characterized in that: The improvement of coffee flavor is to increase the content of flavor substances in coffee beans.

8. The use according to claim 7, characterized in that: The flavor substances include decanal, 5-methylfurfural, hexyl acetate, propyl hexanoate and / or furanone.

9. A fermented coffee, characterized in that: The coffee is prepared by using coffee beans fermented with the strain described in claim 1 or the bacterial agent described in claim 2.

10. The coffee according to claim 9, characterized in that: The content of flavor substances in the coffee is increased, and the flavor substances include decanal, 5-methylfurfural, hexyl acetate, propyl hexanoate and / or furanone.

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