Rhodotorula mucilaginosa PL10 and application thereof in improving quality of sweet rice wine

Abstract

The invention discloses rhodotorula mucilaginosa PL10 and application thereof in improving the quality of sweet rice wine, and belongs to the technical field of microorganisms, and the preservation number of the rhodotorula mucilaginosa PL10 is CCTCC NO: M20241214. The invention finds that the sweet rice wine cooperatively fermented by the rhodotorula mucilaginosa PL10 and the rhizopus oryzae has the highest sensory evaluation score, the content of delicate flavor and sweet amino acids in each group is the highest, the proportion of the delicate flavor and sweet amino acids in the total amino acid content is higher than 75%, the bitter amino acids are less, the types of ester compounds and aldehyde ketone compounds in each group are the highest, and the content of the sweet rice wine is the highest. Therefore, when the sweet rice wine is fermented by the rhodotorula mucilaginosa PL10, the content of bitter amino acid can be obviously reduced, the content of sweet amino acid and the content of delicious amino acid can be obviously increased, the variety of ester compounds and aldehyde ketone compounds of the sweet rice wine can be obviously increased, and the problems that the commercial sweet rice wine is boring in wine taste and fragrance and insufficient in flavor can be effectively solved. The research result provides reference and theoretical basis for preparation of the Yunnan sweet rice wine.

Description

Technical Field

[0001] The invention relates to the technical field of microorganisms, and in particular to a red yeast PL10 and application thereof in improving the quality of sweet rice wine. Background Art

[0002] Sweet rice wine is a traditional fermented food made from glutinous rice, brewed by the joint action of mold, yeast and lactic acid bacteria in the koji. It is deeply loved by the public for its strong aroma, mellow taste, and rich in oligosaccharides, amino acids, organic acids and other nutrients. Koji is an indispensable fermentation agent, saccharifier and flavoring agent for the fermentation of sweet rice wine, and is known as the "bone of wine". In the early stage of fermentation, the abundant root mold in the koji hydrolyzes starch and protein into small molecules such as oligosaccharides, polypeptides, and amino acids; in the later stage of fermentation, the yeast in the koji gradually replaces the root mold and becomes the dominant bacteria in the fermentation process. At this time, brewing yeast converts the sugars produced by the decomposition of mold into alcohols; non-brewing yeast catalyzes alcohols and acids to produce esters. Therefore, the formation of flavor compounds in sweet rice wine is inseparable from yeast. High-quality yeast not only gives sweet rice wine a unique taste and aroma, but also adds a unique regional flavor to it.

[0003] The fermentation of Yunnan sweet rice wine is mainly based on commercial sweet rice koji and traditional koji. Commercial sweet rice wine uses pure rice Rhizopus as a fermentation agent, and its quality is stable but the flavor is insufficient; traditional sweet rice wine uses multi-bacteria koji as a fermentation agent, and its flavor is mellow but easily affected by multiple factors such as fermentation environment, koji and process, and the product flavor quality is unstable; traditional koji is rich in multiple bacteria, so that its fermented sweet rice wine is rich in a variety of "yeast resources", which contains yeasts with high acid and aldehyde production that affect the quality of sweet rice wine; it also contains yeasts with high alcohol and ester production that are beneficial to the quality of sweet rice wine; in order to improve the quality of sweet rice wine, the present application combines rice Rhizopus (commercial sweet rice koji) with high-quality yeast in traditional sweet rice wine to ferment sweet rice wine, in order to achieve complementary advantages between the two. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art, provide a red yeast PL10 and its application in improving the quality of sweet rice wine, so as to develop a high-quality yeast strain that can cooperate with Rhizopus oryzae to ferment high-yield ester compounds and aldehydes and ketone compounds, thereby creating a fermented sweet rice wine with stable flavor quality.

[0005] The present invention is achieved by adopting the following technical solutions:

[0006] The invention provides a red yeast PL10, Rhodotorula mucilaginosa PL10. The living pure culture of the red yeast PL10 has been registered and preserved in the China Center for Type Culture Collection, the preservation address is Wuhan University, No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province, the preservation date is June 13, 2024, and the preservation number is CCTCC NO: M20241214.

[0007] The present invention also provides a sweet rice wine fermentation compound koji containing Rhodotorula glutinosus PL10, wherein the sweet rice wine fermentation compound koji is obtained by compounding the Rhodotorula glutinosus fortified koji obtained by fermenting bran with the Rhodotorula oryzae as claimed in claim 1, and Rhizopus oryzae, and the compounding ratio is preferably 3:7 by mass ratio.

[0008] The present invention also provides an application of red yeast PL10 or a sweet rice wine fermentation compound koji containing red yeast PL10 in improving the quality of sweet rice wine.

[0009] As a further optimization scheme of the present invention, the improvement of the quality of sweet rice wine includes improving the types of ester compounds, aldehyde and ketone compounds, as well as the taste, aroma, appearance and flavor of the sweet rice wine;

[0010] Improving the taste of sweet rice wine includes increasing the content of umami amino acid and sweet amino acid in the sweet rice wine and reducing the content of bitter amino acid in the sweet rice wine.

[0011] The present invention also provides a method for fermenting sweet rice wine, the specific steps of which are as follows:

[0012] Step 1: sieve the bran, add sterile distilled water, stir evenly and sterilize, cool to obtain a bran culture medium, inoculate the red yeast PL10 seed solution as claimed in claim 1 into the bran culture medium, culture at 30° C. for 72 hours, and dry at 38° C. to obtain the red yeast fortified koji, put the red yeast fortified koji into a sterile sampling bag, and store it at 4° C.;

[0013] Step 2: Compounding the red yeast fortified koji prepared in step 1 with Rhizopus oryzae in a mass ratio of 3:7 to obtain a sweet rice wine fermentation compound koji;

[0014] Step 3: Soak glutinous rice in clean water, steam for 10-12 minutes, cool, inoculate with sweet rice wine fermentation compound koji, add sterile water, stir evenly and load into fermentation tank; ferment at 28°C for 60 hours to obtain the crude sweet rice wine fermentation product, sterilize the crude fermentation product in a 75°C water bath for 15 minutes to obtain the finished sweet rice wine product.

[0015] As a further optimization scheme of the present invention, in step 1, the sieve is a 20-mesh sieve, and the amount of sterile water used is 35%-45% of the dry weight of the bran.

[0016] As a further optimization scheme of the present invention, in step three, the dosage of the sweet rice wine fermentation compound koji is 0.7%-0.9% of the dry weight of glutinous rice.

[0017] As a further optimization scheme of the present invention, in step three, the amount of sterile water used is 1.7-1.9 times the dry weight of glutinous rice.

[0018] The beneficial effects of the present invention are:

[0019] The invention separates three high-ester-yielding high-quality yeasts, namely Rhodotorulamucilaginosa PL10, Wickerhamomyces anomalus LF02 and Pichia kudriavzevii, from traditional sweet rice wine in Yunnan. YL15 was used to co-ferment sweet rice wine with Rhizopus oryzae, and its effects on the quality of sweet rice wine were evaluated by sensory evaluation, physicochemical indices, amino acid content and volatile components. Among them, the sweet rice wine co-fermented by Rhodotorula oryzae PL10 had the highest sensory evaluation score, the highest content of umami and sweet amino acids in all groups, and the proportion of umami and sweet amino acids in the total amino acid content was higher than 75%. The bitter amino acids were less, and the types of ester compounds and aldehydes and ketones were also the highest in all groups. This shows that the fermentation of sweet rice wine with Rhodotorula PL10 can significantly reduce the content of bitter amino acids, significantly increase the content of sweet and umami amino acids, and significantly increase the types of ester compounds and aldehydes and ketones in sweet rice wine. It can effectively improve the problems of bland taste and aroma and insufficient flavor of commercial sweet rice wine. The results of this study provide a reference and theoretical basis for the preparation of Yunnan sweet rice wine. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a Venn diagram of the preliminary screening results of yeast strains, where A is a high-fermentation yeast; B is a low-hydrogen sulfide-producing yeast; and A∩B is a high-fermentation low-hydrogen sulfide-producing yeast.

[0021] Figure 2 This is the distribution diagram of aroma types of glutinous rice juice fermented by 27 yeast strains (including control strains).

[0022] Figure 3 Phylogenetic tree of yeast strains constructed based on ITS sequencing.

[0023] Figure 4 This is a dendrogram of the amino acid contents in six groups of sweet rice wines (compound groups CK, JH01, JH02, PL10, LF02, and YL15) (p<0.05).

[0024] Figure 5This is a statistical dendrogram of the flavor substances in six groups of sweet rice wine (compound groups CK, JH01, JH02, PL10, LF02, and YL15) (p<0.05). DETAILED DESCRIPTION

[0025] In order to make the technical means, creative features, objectives and effects of the present invention easier to understand, the present invention is further described below with reference to specific diagrams.

[0026] Example 1

[0027] 1. Materials

[0028] (1) Sixteen samples of sweet rice wine were collected from 16 cities and prefectures in Yunnan: Panlong District, Kunming City, Zhaoyang District, Zhaotong City, Fuyuan County, Qujing City, Maguan County, Wenshan Prefecture, Jianshui County, Honghe Prefecture, Tonghai County, Yuxi City, Lufeng City, Chuxiong Prefecture, Jinghong City, Xishuangbanna Prefecture, Zhenyuan County, Pu'er City, Linxiang District, Lincang City, Dali City, Dali Prefecture, Yulong County, Lijiang City, Mangshi City, Dehong Prefecture, Tengchong City, Baoshan City, Lushui City, Nujiang Prefecture, and Shangri-La City, Diqing Prefecture. All samples were home-brewed by farmers.

[0029] (2) Commercially available glutinous rice, bran, Rhizopus oryzae, and Hansenula AQ;

[0030] (3) Red yeast JH01: Rhodotorula mucilaginosa AS2.1.034, purchased from Shanghai Collection of Microorganisms Center; Red yeast JH02: Rhodotorula mucilaginosa AS2.530, purchased from Beijing Collection Biotechnology Co., Ltd.

[0031] The methods used in this example are conventional methods known to those skilled in the art unless otherwise specified, and the reagents and other materials used are commercially available products unless otherwise specified.

[0032] 2. Methods

[0033] 2.1 Isolation and purification of yeast

[0034] Sixteen sweet rice wine samples were graded diluted with sterile water, and the dilutions were spread on YPD, PDA and Bengal rose culture media respectively, and cultured at 28°C for 72 hours. Single colonies with typical yeast characteristics were isolated, purified and preserved.

[0035] 2.2 Yeast screening

[0036] Glutinous rice juice culture medium: soak 150g glutinous rice in water for 9h, steam for 10-12min, then cool to 30℃, inoculate with 0.8% commercial sweet wine koji (based on the weight of glutinous rice, dry basis), culture at 28℃ for 36h, add 400mL distilled water and shake well, saccharify at 60℃ for 6h, boil for 5min, filter while hot, and sterilize under high pressure at 121℃ for 15min.

[0037] The yeast suspension isolated and purified in step 2.1 above was inoculated into a glutinous rice juice medium (containing Dulbecco's tubules) with a sugar content of 11Birx at 1% (V / V) and cultured at 28°C for 48h. The gas production in the Dulbecco's tubules was observed every 12h. The yeast whose Dulbecco's tubules were filled with gas within 48h was considered to be a high-fermentation yeast; 5μL of the yeast suspension was inoculated into Biggy agar agar medium and cultured at 28°C for 72h. The bismuth ions in the Biggy agar medium reacted with the hydrogen sulfide produced by the yeast to form bismuth sulfide, causing the colonies to change from white to yellow to brown to dark brown; the darker the color, the more hydrogen sulfide the yeast produced, and the white or yellow colonies were low hydrogen sulfide-producing yeasts; Hansenula AQ was used as a control group to compare the characteristics of the isolated yeast.

[0038] Preliminary screening results: 419 yeast strains were isolated from 16 sweet rice wine samples. The 419 yeast strains were named according to the locations where the yeast strains were isolated. Hansenula AQ was used as the control group, and a total of 420 yeast strains were tested for fermentation performance.

[0039] like Figure 1 As shown, 275 yeast strains produced gas that did not fill the Durex tubules within 48 hours of fermentation, and their fermentation rate was extremely low and no longer suitable for fermentation; during the fermentation process, yeast would decompose sulfur-containing compounds such as sulfur-containing amino acids, sulfates and sulfites to produce H2S with a rotten egg smell. In the further reaction of hydrogen sulfide, its sulfur atom replaced the oxygen atom of alcohol to form unpleasant and toxic thiols, so 67 strains of high-producing H2S yeast were discharged; the remaining 78 strains (including the control strain) of yeast were high-fermentation and low-producing H2S yeast, which were subjected to the next step of performance analysis.

[0040] 2.3 Rescreening of high ester-producing yeasts

[0041] The olfactory method was used to screen aroma-producing yeasts from the 78 strains (including the control strain) of yeast isolated in step 2.2 above. A total of 27 strains (including the control strain) of aroma-producing and comfortable yeasts were screened out. The aroma types ( Figure 2 ) were divided into: wine aroma (12 strains, 44.5%), fruity aroma (11 strains, 40.7%), and fresh aroma (4 strains, 14.8%). The control group (Hansenula AQ) had a wine aroma;

[0042] In order to screen out yeasts with high ester production, the ester production of aroma-producing yeasts was determined by saponification titration method. The above 27 strains (including control strains) of aroma-producing and comfortable yeasts and the control group (Hansenula AQ) were mixed at 1×10 7 CFU / mL was inoculated into 50mL glutinous rice juice and fermented at 30℃ for 72h. The total ester content of the fermented glutinous rice juice was determined to compare the ester production ability of each yeast, and three yeast strains with high ester production were screened out, namely yeast LF02, YL15, and PL10, with ester production of 4.22g / L, 4.85g / L, and 4.88g / L, respectively. Under the same fermentation conditions, the total ester content of glutinous rice juice fermented by LF02, YL15, and PL10 was significantly higher than that of other groups. The three yeasts LF02, YL15, and PL10 with good alcohol production, high ester production, and comfortable aroma production have the potential to solve the problems of commercial sweet rice wine with bland taste and aroma and insufficient flavor.

[0043] 2.4 Strain identification

[0044] The ITSDNA sequences of the three high-quality yeast strains selected in step 2.3 above were determined, and the sequencing results were analyzed by BLAST in NCBI. The yeast strain development tree was constructed using MEGA6 ( Figure 3 ), the identification results showed that yeast LF02 was Wickerhamomyces anomalus, yeast YL15 was Pichia kudriavzevii, and yeast PL10 was Rhodotorula mucilaginosa.

[0045] 2.5 Preparation of sweet rice wine

[0046] 2.5.1. Preparation of single-bacteria yeast koji

[0047] The bran was passed through a 20-mesh sieve, 40% sterile distilled water (based on the weight of the bran, dry basis) was added, stirred evenly, and sterilized at 121°C for 20 min. 5 CFU / g The seed liquid of yeast LF02, YL15 and PL10 were inoculated into the bran culture medium (cooled to 30℃), cultured at 30℃ for 72h, and dried at 38℃ for 24h. The dried single-bacteria yeast bran koji was put into sterile sampling bags and stored at 4℃.

[0048] 2.5.2. Fermentation of sweet rice wine with single-bacteria yeast koji and Rhizopus oryzae

[0049] The commercial sweet wine koji (Rhizopus oryzae, 3.5×105 CFU / g) and the homemade single-bacteria yeast koji (yeast LF02, YL15, PL10) prepared in step 2.5.1 were compounded in a mass ratio of 7:3 to obtain compound koji, and sweet rice wine was fermented with the compound koji. The commercial sweet wine koji (Rhizopus oryzae) and commercial brewing yeast koji (Hansenula AQ) were compounded (mass ratio 7:3) as a control group (CK), and the commercial sweet wine koji (Rhizopus oryzae) was compounded with Rhodotorula mucilaginosa AS2.1.034 and Rhodotorula mucilaginosa AS2.530) as a comparison group.

[0050] Soak 200g of glutinous rice in clean water for 9h, steam the glutinous rice for 10-12min, inoculate 0.8% (by weight of glutinous rice, dry basis) of compound koji in the glutinous rice cooled to 30°C, add 375mL of sterile water, stir evenly, and put into a fermentation tank; ferment at 28°C for 60h to obtain a crude sweet rice wine fermentation product; sterilize the crude fermentation product in a 75°C water bath for 15min to obtain a finished sweet rice wine product.

[0051] 3 Sweet rice wine performance test

[0052] 3.1 Sensory evaluation of sweet rice wine

[0053] Under the experimental conditions of good ventilation and no odor, the sensory evaluation team (10 food major students, half male and half female) conducted a systematic sensory evaluation on the sweet rice wine samples, scoring the four items of sweet rice wine taste, aroma, appearance and overall flavor. The average of the scores was taken as the final score of the project, with a full score of 100. The evaluation criteria are shown in Table 1:

[0054] Table 1 Sensory scoring standards for sweet rice wine

[0055]

[0056]

[0057] The sensory evaluation scores of each group of sweet rice wine are shown in Table 2:

[0058] Table 2 Sensory evaluation of sweet rice wine

[0059]

[0060] Note: The compound groups CK, JH01, JH02, PL10, LF02 and YL15 represent the sweet rice wine fermented by Hansenula AQ, Rhodotorulamucilaginosa AS2.1.034, Rhodotorula mucilaginosa AS2.530, Rhodotorula mucilaginosa PL10, Wickerhamomyces anomalus LF02, Pichiakudriavzevii YL15 and Rhizopus oryzae, respectively.

[0061] Experimental conclusion: The sweet rice wine fermented by the compound group CK has a sour and astringent taste, bland flavor, and inharmonious wine body components; the sweet rice wine fermented by the compound groups JH01 and JH02 has a strong ester aroma but insufficient wine aroma, and the taste is sour and astringent and the wine body components are inharmonious; the sweet rice wine fermented by the compound group LF02 has a strong ester aroma, a sour and bitter taste, and inharmonious wine body components; the sweet rice wine fermented by the compound group YL15 has an appropriate sour and sweet taste and a mellow taste, but only a slight sweet rice wine fermentation aroma; the sweet rice wine fermented by the compound group PL10 has an appropriate sour and sweet taste, is fresh and refreshing, has a strong ester aroma, has the unique aroma of grain fermentation, and has harmonious wine body components with a unique flavor of sweet rice wine. Its aroma and comprehensive sensory scores are the best among all groups; Therefore, the red yeast PL10 has important potential to solve the bland taste and aroma and insufficient flavor of Yunnan sweet rice wine.

[0062] 3.2 Physical and chemical indicators of sweet rice wine

[0063] The crude protein in the grains was determined by the Dumas combustion method, on a dry basis; the reducing sugar in the juice was determined by the DNS method; the total sugar in the juice was determined by the phenol-sulfuric acid method; the soluble solids in the juice were determined by a handheld refractometer method; the acidity was determined by a pH meter method; and the alcohol content was determined in accordance with GB / T 13662-2008 "Yellow Wine".

[0064] Table 4 Statistical table of physical and chemical indicators of sweet rice wine

[0065]

[0066] Note: Different superscript letters in the figure indicate significant differences between the data (p<0.05).

[0067] The pH of the six groups of sweet rice wines was 3.42-3.92, the crude protein of the grains was 13.19%-22.49%, the soluble solids was 35.07%-41.77%, the ethanol of the wine was 2.73-4.47 vol%, the reducing sugar was 232.16-296.76 mg / mL, and the total sugar was 292.71-357.94 mg / mL; among them, the ethanol production capacity of the composite group PL10 was also significantly higher than that of the other groups (p<0.05), and combined with the above-mentioned sensory evaluation results of sweet rice wine, it can be explained that the gum red yeast PL10 has the effect of solving the problem of bland taste and aroma and insufficient flavor of commercial sweet rice wine.

[0068] 3.3 Effect of compound koji on amino acids in sweet rice wine

[0069] The free amino acid content in sweet rice wine juice was determined according to the method of QBT 4356-2012. Sample pretreatment: 20 mL sweet rice wine juice was ultrasonicated for 10 min, centrifuged at 8000 r / min for 5 min, 2 mL sweet rice wine juice supernatant and 6 mL 6 mol / L HCL solution (containing 0.1% phenol) were taken in an ampoule. The sealed ampoule was placed in a 105°C environment for hydrolysis for 22 h, cooled to room temperature and taken. 1 mL of sample hydrolyzate was freeze-dried in an injection bottle, 0.1 mol / L HCL solution was taken to re-dissolve to 1 mL, 0.5 mL of the re-solution was taken and placed in a plunger test tube, 250 μL of 0.1 mol / L phenyl isothiocyanate acetonitrile solution and 250 μL of 1 mol / L triethylamine-acetonitrile solution were added, mixed, placed at room temperature for 60 min, 1 mL of n-hexane was added and placed at room temperature for 10 min, and 0.5 mL of the bottom layer of solution was taken after stratification for HPLC analysis.

[0070] The test results are as follows Figure 4 As shown, the proportions of umami amino acids (425.18 μg / mL), sweet amino acids (740.51 μg / mL), and bitter amino acids (249.16 μg / mL) in the compound group PL10 were 30.05%, 52.34%, and 17.61%, respectively (p<0.05). The umami and sweet amino acids contents of the sweet rice wine fermented by the compound group PL10 were higher, and the umami and sweet amino acids contents accounted for more than 75% of the total amino acid content, while the bitter amino acids were less. The umami and sweet amino acids contents were significantly higher than those of the other groups and the control group CK, while the bitter amino acids content was significantly lower than that of the other groups and the control group CK. On the other hand, the bitter amino acids contents in the sweet rice wine fermented by the two strains of red yeast (JH01 and JH02) were both relatively high. Therefore, it is believed that the red yeast PL10 can significantly reduce the proportion of bitter amino acids and significantly increase the proportion of sweet and umami amino acids in the sweet rice wine fermented by sweet yeast, which has the effect of improving the taste and aroma of commercial sweet rice wine, as well as the lack of flavor.

[0071] 3.4 Analysis of volatile substances in sweet rice wine

[0072] In a 20mL headspace injection bottle, add 1g NaCl, inject 4.9mL rice wine sample, and 0.1mL 2-octanol (500μg / mL). Place the headspace bottle in a 45℃ water bath for 10min, use a 50 / 30μm DVB / CAR / PDMS three-phase extraction head, extract the headspace for 40min, and inject the sample into a gas chromatograph for mass spectrometry detection.

[0073] The test results are as follows Figure 5 As shown in the results, the types of ester compounds and aldehydes and ketones in sweet rice wine fermented by Rhodotorula PL10 were significantly higher than those in other groups (p<0.05). Ester compounds are the most important flavor compounds in wine. Most esters have the aroma of flowers and fruits, which can increase the complexity and typicality of the aroma of the wine. Aldehydes and ketones are important components of the aroma of sweet rice wine. When combined with other compounds, they will produce aromatic compounds that help enhance the complexity and balance of the wine.

[0074] In summary, Rhodotorula PL10 is a high-ester-yielding, high-quality yeast. Using it as a candidate yeast resource for the fermentation agent of Yunnan sweet rice wine can effectively improve the problems of bland taste and aroma and insufficient flavor of Yunnan sweet rice wine, and provide technical support for the modernization and upgrading of Yunnan sweet rice wine industry and the exploration of microbial resources of characteristic fermented foods.

[0075] 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 red yeast strain PL10, Rhodotorula mucilaginosa PL10, It is characterized in that The living pure culture of the red yeast PL10 has been registered and preserved in the China Center for Type Culture Collection, with the preservation date being June 13, 2024, and the preservation number being CCTCC NO: M20241214.

2. A sweet rice wine fermentation compound koji containing red yeast PL10, It is characterized in that The sweet rice wine fermentation compound koji is obtained by compounding the koji red yeast fortified koji obtained by fermenting bran with the red yeast PL10 as claimed in claim 1 and Rhizopus oryzae.

3. A sweet rice wine fermentation compound koji containing Rhodotorula PL10 according to claim 2, It is characterized in that The red yeast fortified koji and Rhizopus oryzae are compounded in a mass ratio of 3:

7.

4. Use of the Rhodotorula glutinosus PL10 as claimed in claim 1 or the sweet rice wine fermentation compound koji containing the Rhodotorula glutinosus PL10 as claimed in any one of claims 2 to 3 in improving the quality of sweet rice wine.

5. The use according to claim 4, Features: Improving the quality of sweet rice wine includes improving the types of ester compounds, aldehyde and ketone compounds, as well as the taste, aroma, appearance and flavor of the sweet rice wine; Improving the taste of sweet rice wine includes increasing the content of umami amino acid and sweet amino acid in the sweet rice wine and reducing the content of bitter amino acid in the sweet rice wine.

6. A method for fermenting sweet rice wine, It is characterized in that The specific steps are as follows: Step 1: sieve the bran, add sterile distilled water, stir evenly and sterilize, cool to obtain a bran culture medium, inoculate the red yeast PL10 seed solution as claimed in claim 1 into the bran culture medium, culture at 30° C. for 72 hours, and dry at 38° C. to obtain the red yeast fortified koji, put the red yeast fortified koji into a sterile sampling bag, and store it at 4° C.; Step 2: Compounding the red yeast fortified koji prepared in step 1 with Rhizopus oryzae in a mass ratio of 3:7 to obtain a sweet rice wine fermentation compound koji; Step 3: Soak glutinous rice in clean water, steam for 10-12 minutes, cool, inoculate with sweet rice wine fermentation compound koji, add sterile water, stir evenly and load into fermentation tank; ferment at 28°C for 60 hours to obtain the crude sweet rice wine fermentation product, sterilize the crude fermentation product in a 75°C water bath for 15 minutes to obtain the finished sweet rice wine product.

7. A method for fermenting sweet rice wine according to claim 6, It is characterized in that In step 1, the sieve is a 20-mesh sieve, and the amount of sterile water used is 35%-45% of the dry weight of bran.

8. A method for fermenting sweet rice wine according to claim 6, It is characterized in that In step three, the dosage of the sweet rice wine fermentation compound koji is 0.7%-0.9% of the dry weight of glutinous rice.

9. A method for fermenting sweet rice wine according to claim 6, It is characterized in that In step three, the amount of sterile water used is 1.7-1.9 times the dry weight of glutinous rice.

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