A method for improving the quality of baijiu by using microbial community

Abstract

The present application relates to the technical field of liquor brewing, and particularly relates to a method for improving liquor quality by using microbial communities, wherein rice, sorghum and glutinous rice are mixed uniformly, soaked and steamed, saccharified by adding small koji, mixed with microbial composition A for fermentation, distillation and aging to obtain high-quality liquor, wherein the small koji is prepared by mother koji and microbial composition B; the inulin in the mother koji can enhance the activity of microorganisms, improve the community structure of microorganisms, and synergistically act with the microbial composition B, thereby improving the aroma and taste of the liquor; and the rice, sorghum and the like after saccharification have entered the semi-solid or solid fermentation stage, and can produce acids and esters; then, through the metabolic activity of the microbial composition A, the esterification reaction is accelerated, thereby generating a large amount of aroma substances, improving the liquor quality and shortening the aging period; compared with the prior art, the method has a wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of baijiu (Chinese liquor) brewing technology, and in particular to a method for improving the quality of baijiu by utilizing microbial communities. Background Technology

[0002] Baijiu, my country's national liquor, refers to a distilled spirit made primarily from grains, using various types of koji (fermentation starter) made from microorganisms as saccharification and fermentation agents, through processes such as cooking, saccharification, fermentation, distillation, aging, and blending. The brewing process of baijiu is complex and closely related to various production conditions, such as the climate and environment of the production area, the water used for brewing, the grains, and the koji. Therefore, Chinese baijiu possesses a diverse range of flavors.

[0003] Baijiu (Chinese white liquor) contains compounds such as terpenes and alcohols, which have the effects of enhancing human immunity, preventing diseases, and promoting recovery. The fermentation process of baijiu involves dynamic changes in the phytochemical system, enzyme system, microbial system, and fermentation conditions. The content of ethyl acetate affects the quality and style of baijiu. The formation of ethyl acetate is influenced by the external environment and exhibits a certain degree of fluctuation.

[0004] In recent years, with the rise in baijiu (Chinese liquor) market prices, baijiu brewing has become a pillar industry in many regions. The booming baijiu market has spurred innovative development in traditional baijiu brewing techniques. However, baijiu produced using traditional methods, due to its high grain consumption, high energy consumption, long production cycle, and low production efficiency, falls far short of meeting the demand for high-quality baijiu from consumers, seriously hindering the development of enterprises and the industry as a whole. Therefore, it is imperative to improve baijiu brewing processes using modern bio-fermentation technology to enhance baijiu quality and resource utilization.

[0005] The quality of baijiu (Chinese white liquor) varies depending on the raw materials, fermenting agents, production processes, and fermentation environment. Currently, domestically produced baijiu is mainly classified by aroma type: strong aroma, light aroma, clear aroma, and rice aroma. Among these, strong aroma baijiu has the largest production volume and is highly favored by consumers. Many factories and research institutions have conducted extensive research on the strong aroma baijiu brewing process. Analysis of the flavor compounds in baijiu shows that these aroma compounds mainly include alcohols, aldehydes, ketones, acids, and esters, originating from the brewing raw materials and microbial metabolites. It is evident that microorganisms play a crucial role in every stage of brewing, as they depend on the nutrients in the raw materials for survival. Through their own community succession and growth metabolism, they form a large number of fermentation metabolites, laying the foundation for the unique body and style of baijiu.

[0006] In the prior art, such as patent document CN112011424A, a mellow and mellow sauce-flavored liquor is disclosed, which is made by fermentation of compound grains. The compound grains include a mixture of two or more types of grains such as sorghum, rice, corn, wheat, and glutinous rice. The liquor is then fermented through a process of initial fermentation, coarse fermentation, multiple distillations, storage, and blending. The compound grain fermentation in this invention is more complete, which reduces production costs, but the quality of the brewed liquor still needs to be improved.

[0007] Therefore, based on the aforementioned technologies, there is an urgent need to develop a method for improving the quality of baijiu (Chinese liquor) using microbial communities. Summary of the Invention

[0008] In view of this, the purpose of this invention is to propose a method for improving the quality of baijiu (Chinese liquor) by utilizing microbial communities, so as to solve the problem of poor baijiu quality in the prior art.

[0009] To achieve the above objectives, the present invention provides a method for improving the quality of baijiu (Chinese liquor) by utilizing microbial communities.

[0010] A method for improving the quality of baijiu (Chinese liquor) using microbial communities includes the following steps:

[0011] Step S1. Grind the rice, sorghum and glutinous rice, mix them together, soak them in hot water, drain them, steam them and spread them out to cool to obtain the cooked mixture.

[0012] Step S2. Sprinkle the koji into the cooked material in 5 batches and mix evenly. Keep warm and pile up to obtain the saccharified cooked material.

[0013] Step S3. After mixing the saccharified cooked material and microbial composition A evenly, put it into a fermentation pit for fermentation, and then distill it to obtain baijiu (Chinese liquor);

[0014] Step S4. Mix the distilled liquor with microbial composition A to obtain an aging and fermentation mixture for aging. Then, purify the mixture with oxygen for 2-5 hours per day for 16-24 days to obtain high-quality liquor.

[0015] The small starter culture mentioned in step S2 is prepared by mixing the mother starter culture and microbial composition B at a mass ratio of 100-120:22-30;

[0016] The microbial composition B was prepared from Lactobacillus acidophilus and Bacillus lysine.

[0017] The microbial composition A described in step S3 is prepared from Saccharomyces cerevisiae, ester-producing yeast, Bifidobacterium longum, and Lactobacillus rhamnosus.

[0018] Preferably, the mass ratio of rice, sorghum, and glutinous rice in step S1 is 35-50:62-88:13-28;

[0019] The temperature of the hot water is 60-75℃, and the soaking time is 8-11 hours;

[0020] The steaming time is 35-45 minutes.

[0021] Preferably, the method for preparing the master batch is as follows:

[0022] Take wheat, spray it with water to moisten it, then crush it and mix it with fresh wheat bran, kudzu root powder and inulin. Add water and mix well. Then divide it into Erlenmeyer flasks, with the filling thickness not exceeding 2cm. Wrap the flasks with 8 layers of gauze and seal them. Then wrap them with kraft paper for sterilization and place them in a sterile room. When the temperature drops to 30°C, use an inoculation loop to pick up mold spores of Rhizopus nigricans and Rhizopus oryzae and inoculate them into the Erlenmeyer flasks respectively. After mixing well, place them in an incubator at 28-30°C for 46-48 hours. When the surface of the bran is covered with mycelium, invert the flasks and incubate for 5-6 days. After drying and mixing, the mother koji is obtained and stored at 4°C.

[0023] Preferably, the mass ratio of wheat, fresh wheat bran, kudzu root powder and inulin is 22-30:18-25:8-12:6-9;

[0024] The drying temperature is 35-40°C and the time is 4-5 hours.

[0025] The mass ratio of Rhizopus nigricans to Rhizopus oryzae during the mixing process is 9-15:4-7.

[0026] Preferably, the preparation method of the microbial composition B is as follows:

[0027] Lactobacillus acidophilus and Bacillus lysine were activated in sterile culture medium at 37°C for 22-24 hours, then centrifuged at 4000-5000 rpm for 15-20 minutes. The supernatant was discarded, the bacterial cells were collected, and bacterial suspensions were prepared with sterile water to obtain Lactobacillus acidophilus suspension and Bacillus lysine suspension respectively. The Lactobacillus acidophilus suspension and Bacillus lysine suspension were then mixed to obtain microbial composition B.

[0028] Preferably, the culture medium formula is as follows: 10g peptone, 10g beef extract, 5g yeast extract, 20g glucose, 1mL Tween-80, 2g diammonium hydrogen citrate, 5g sodium acetate, 2g dipotassium hydrogen phosphate, 0.58g magnesium sulfate heptahydrate, 0.25g manganese sulfate tetrahydrate, 1000mL distilled water, pH 6.8;

[0029] The mass ratio of the Lactobacillus acidophilus suspension to the Bacillus lysine suspension is 8-14:5-9;

[0030] The viable count of Lactobacillus acidophilus in the microbial composition B is 110. 8 -110 10CFU / g, viable count of Bacillus lysine is 1 x 10⁻⁶. 6 -10 8 CFU / g.

[0031] Preferably, the preparation method of the microbial composition A is as follows:

[0032] Saccharomyces cerevisiae, ester-producing yeast, Bifidobacterium longum, and Lactobacillus rhamnosus were activated in sterile culture medium at 37°C for 22-24 hours, then centrifuged at 4000-5000 rpm for 15-20 minutes. The supernatant was discarded, the bacterial cells were collected, and bacterial suspensions were prepared with sterile water to obtain Saccharomyces cerevisiae, ester-producing yeast, Bifidobacterium longum, and Lactobacillus rhamnosus bacterial suspensions, respectively. The Saccharomyces cerevisiae, ester-producing yeast, Bifidobacterium longum, and Lactobacillus rhamnosus bacterial suspensions were then mixed to obtain microbial composition A.

[0033] Preferably, the mass ratio of the Saccharomyces cerevisiae suspension, the ester-producing yeast suspension, the Bifidobacterium longum suspension, and the Lactobacillus rhamnosus suspension is 10-15:8-12:2-5:4-7.

[0034] The viable count of the Saccharomyces cerevisiae suspension in the microbial composition A is 510. 8 -510 10 CFU / mL, viable count of ester-producing yeast suspension was 310. 7 -310 9 The CFU / mL count of Bifidobacterium longum was 2.210. 7 -2.210 10 CFU / mL, viable count of Lactobacillus rhamnosus was 210. 7 -210 8 CFU / mL.

[0035] Preferably, the mass ratio of the small koji and the clinker in step S2 is 0.4-0.6:9-12;

[0036] The mass ratio of the saccharified cooked material and the microbial composition A in step S3 is 8-10:0.2-0.5.

[0037] Preferably, the distillation temperature in step S3 is 78-85℃ and the time is 40-55 min;

[0038] The mass ratio of the distilled liquor and the microbial composition A obtained in step S4 is 40-50:0.01-0.03.

[0039] The beneficial effects of this invention are:

[0040] This invention provides a method for improving the quality of baijiu (Chinese liquor) using microbial communities. The method involves uniformly mixing rice, sorghum, and glutinous rice, soaking and steaming the mixture, adding koji (a type of starter culture) for saccharification, and then mixing it with microbial composition A for fermentation, distillation, and aging to obtain high-quality baijiu. The koji is prepared from a mother koji and microbial composition B. The inulin in the mother koji enhances the activity of microorganisms and improves the microbial community structure, working synergistically with microbial composition B to improve the aroma and taste of the baijiu. The saccharified rice and sorghum have entered a semi-solid or solid-state fermentation stage, producing acids and esters. When mixed with microbial composition A for fermentation and distillation, the metabolic activity of microbial composition A accelerates the esterification reaction, generating a large amount of aroma compounds, thus improving the quality of the baijiu and shortening the aging period. Compared with existing technologies, this method has broad application prospects. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0042] The sources and properties of some of the raw materials used in this invention are as follows:

[0043] Rice was purchased from Jiangsu Jiangnanchun Rice Industry Co., Ltd.; sorghum was purchased from Jilin Zhuangyi Seed Industry Co., Ltd.; glutinous rice was purchased from Foshan Shunde Nuomigou Trading Co., Ltd.; kudzu root powder was purchased from Guangxi Zhuang Autonomous Region Tengxian Green Pastoral Kudzu Industry Co., Ltd.; inulin was purchased from Hunan Guiwei Biotechnology Co., Ltd.

[0044] The lysine-producing Bacillus used in this invention is lysine-producing Bacillus GJ-1, which is disclosed in the invention patent with authorization announcement number CN114276948B and titled "Lysine-producing Bacillus hexanoic acid and its uses", and accession number CCTCCNO: M 2020935.

[0045] The Lactobacillus acidophilus used in this invention is disclosed in the invention patent with the authorized publication number CN116286524A, entitled "A Probiotic Combination for Improving Constipation in Pregnant Women and Its Products and Uses", and the accession number is CGMCC No.1.2686;

[0046] The brewing yeast used in this invention is disclosed in the invention patent with authorization announcement number CN114395513B, entitled "A Microbial Agent for Brewing Light-Aroma Baijiu and Its Application", and accession number CGMCC No.8130.

[0047] The ester-producing yeast used in this invention is Debaryomyceshansenii H32, which is disclosed in the invention patent with the authorized publication number CN113583883A and the title of an ester-producing yeast Debaryomyceshansenii H32 and its application, and the accession number is GDMCCNO:61716.

[0048] The Bifidobacterium longum used in this invention is disclosed in the invention patent with the authorized publication number CN116286524A, entitled "A Probiotic Combination for Improving Constipation in Pregnant Women and Its Products and Uses", and the accession number is CGMCC No.1.2186;

[0049] The Lactobacillus rhamnosus used in this invention is Lactobacillus rhamnosus VHProbi M15, which is disclosed in the invention patent with authorization announcement number CN114717129B and titled "A strain of Lactobacillus rhamnosus and its application in the prevention and relief of constipation symptoms", and accession number CCTCC NO: M2021904.

[0050] The Rhizopus nigricans used in this invention is disclosed in the invention patent with the authorized publication number CN106591160A, entitled "A method for producing compound koji and koji liquor", and the accession number is CCTCC M 2016412.

[0051] The Rhizopus oryzae used in this invention is disclosed in the invention patent with the authorized publication number CN106591160A, entitled "A Method for Producing Compound Small-Scale Batch and Small-Scale Batch Baijiu", and the accession number CCTCC M 2016413.

[0052] Example 1: A method for improving the quality of baijiu (Chinese liquor) using microbial communities, comprising the following steps:

[0053] S1. Weigh 10g peptone, 10g beef extract, 5g yeast extract, 20g glucose, 2g diammonium citrate, 5g sodium acetate, 2g dipotassium hydrogen phosphate, 0.58g magnesium sulfate heptahydrate and 0.25g manganese sulfate tetrahydrate, add 1000mL distilled water and 1mL Tween-80 and stir until completely dissolved. Adjust the pH to 6.8, filter, and sterilize at 121℃ for 15min to obtain the culture medium.

[0054] S2. Saccharomyces cerevisiae, ester-producing yeast, Bifidobacterium longum, and Lactobacillus rhamnosus were activated in sterile culture medium at 37°C for 22 h, then centrifuged at 4000 rpm for 15 min, the supernatant was discarded, the bacterial cells were collected, and bacterial suspensions were prepared with sterile water to obtain Saccharomyces cerevisiae suspension, ester-producing yeast suspension, Bifidobacterium longum suspension, and Lactobacillus rhamnosus suspension, respectively. Then, 10 g of Saccharomyces cerevisiae suspension, 8 g of ester-producing yeast suspension, 2 g of Bifidobacterium longum suspension, and 4 g of Lactobacillus rhamnosus suspension were mixed to obtain microbial composition A.

[0055] S3. Lactobacillus acidophilus and Bacillus lysine were activated in sterile culture medium at 37°C for 22 h, then centrifuged at 4000 rpm for 15 min, the supernatant was discarded, the bacterial cells were collected, and bacterial suspensions were prepared with sterile water to obtain Lactobacillus acidophilus suspension and Bacillus lysine suspension respectively. Then, 8 g of Lactobacillus acidophilus suspension and 5 g of Bacillus lysine suspension were mixed to obtain microbial composition B.

[0056] S4. Take 22g of wheat, spray it with water to moisten it, crush it, mix it with 18g of fresh wheat bran, 8g of kudzu root powder and 6g of inulin, add water, mix the mixture evenly, and then divide it into Erlenmeyer flasks. The thickness of the mixture should not exceed 2cm. Wrap the flasks with 8 layers of gauze to seal them, and then wrap them with kraft paper to sterilize them. Place them in a sterile room and wait until they cool to 30°C. Use an inoculation loop to pick up the mold spores of Rhizopus nigricans and Rhizopus oryzae and inoculate them into the Erlenmeyer flasks respectively. Mix them well and place them in a 28°C incubator for 46 hours. When the surface of the bran is covered with mycelium, invert the flasks and incubate for 5 days. Dry them at 35°C for 4 hours. Mix 9g of Rhizopus nigricans and 4g of Rhizopus oryzae to obtain the mother koji and store it at 4°C.

[0057] S5. Crush 35g of rice, 62g of sorghum and 13g of glutinous rice and mix them together. Soak them in 60℃ hot water for 8 hours. After draining, steam the mixture for 35 minutes and spread it out to cool to obtain the cooked mixture.

[0058] S6. Mix 100g of mother koji and 22g of microbial composition B evenly to obtain small koji. Then, sprinkle 0.4g of small koji on 9g of cooked material in 5 portions and mix evenly. Keep warm and pile up to obtain saccharified cooked material.

[0059] S7. Mix 8g of saccharified cooked material and 0.2g of microbial composition A evenly, put it into a fermentation pit, and distill it at 78℃ for 40 minutes to obtain baijiu (Chinese liquor);

[0060] S8. Mix 40g of the distilled liquor with 0.01g of microbial composition A to obtain an aging and fermentation mixture for aging. Then, purify the mixture with oxygen for 2 hours a day for 16 consecutive days to obtain high-quality liquor.

[0061] Example 2: A method for improving the quality of baijiu (Chinese liquor) using microbial communities, comprising the following steps:

[0062] S1. Weigh 10g peptone, 10g beef extract, 5g yeast extract, 20g glucose, 2g diammonium citrate, 5g sodium acetate, 2g dipotassium hydrogen phosphate, 0.58g magnesium sulfate heptahydrate and 0.25g manganese sulfate tetrahydrate, add 1000mL distilled water and 1mL Tween-80 and stir until completely dissolved. Adjust the pH to 6.8, filter, and sterilize at 121℃ for 15min to obtain the culture medium.

[0063] S2. Saccharomyces cerevisiae, ester-producing yeast, Bifidobacterium longum, and Lactobacillus rhamnosus were activated in sterile culture medium at 37°C for 23 h, then centrifuged at 4500 rpm for 18 min, the supernatant was discarded, the bacterial cells were collected, and bacterial suspensions were prepared with sterile water to obtain Saccharomyces cerevisiae suspension, ester-producing yeast suspension, Bifidobacterium longum suspension, and Lactobacillus rhamnosus suspension, respectively. Then, 13 g of Saccharomyces cerevisiae suspension, 10 g of ester-producing yeast suspension, 4 g of Bifidobacterium longum suspension, and 5 g of Lactobacillus rhamnosus suspension were mixed to obtain microbial composition A.

[0064] S3. Lactobacillus acidophilus and Bacillus lysine were activated in sterile culture medium at 37°C for 23 h, then centrifuged at 4500 rpm for 18 min, the supernatant was discarded, the bacterial cells were collected, and bacterial suspensions were prepared with sterile water to obtain Lactobacillus acidophilus suspension and Bacillus lysine suspension respectively. Then, 12 g of Lactobacillus acidophilus suspension and 7 g of Bacillus lysine suspension were mixed to obtain microbial composition B;

[0065] S4. Take 26g of wheat, spray it with water to moisten it, crush it, mix it with 22g of fresh wheat bran, 10g of kudzu root powder and 8g of inulin, add water, mix the mixture evenly, and then divide it into Erlenmeyer flasks. The thickness of the filling should not exceed 2cm. Wrap the flasks with 8 layers of gauze and seal them. Then wrap them with kraft paper for sterilization. Place them in a sterile room and wait for them to cool to 30°C. Use an inoculation loop to pick up the mold spores of Rhizopus nigricans and Rhizopus oryzae and inoculate them into the Erlenmeyer flasks respectively. Mix them well and place them in an incubator at 29°C for 47h. When the surface of the bran is covered with mycelium, invert the flasks and incubate for 5 days. Dry them at 37°C for 4.5h. Mix 12g of Rhizopus nigricans and 6g of Rhizopus oryzae to obtain the mother koji and store it at 4°C.

[0066] S5. Crush 43g of rice, 75g of sorghum and 20g of glutinous rice and mix them together. Soak them in 68℃ hot water for 10 hours. After draining, steam the mixture for 40 minutes and spread it out to cool to obtain the cooked mixture.

[0067] S6. Mix 110g of mother koji and 26g of microbial composition B evenly to obtain small koji. Then, sprinkle 0.5g of small koji on 11g of cooked material in 5 portions and mix evenly. Keep warm and pile up to obtain saccharified cooked material.

[0068] S7. Mix 9g of saccharified cooked material and 0.3g of microbial composition A evenly, put them into a fermentation pit for fermentation, and distill at 82℃ for 48 minutes to obtain baijiu (Chinese liquor);

[0069] S8. Mix 45g of the distilled liquor with 0.02g of microbial composition A to obtain an aging and fermentation mixture for aging. Then, purify the mixture with oxygen for 3 hours a day for 20 consecutive days to obtain high-quality liquor.

[0070] Example 3: A method for improving the quality of baijiu (Chinese liquor) using microbial communities, comprising the following steps:

[0071] S1. Weigh 10g peptone, 10g beef extract, 5g yeast extract, 20g glucose, 2g diammonium citrate, 5g sodium acetate, 2g dipotassium hydrogen phosphate, 0.58g magnesium sulfate heptahydrate and 0.25g manganese sulfate tetrahydrate, add 1000mL distilled water and 1mL Tween-80 and stir until completely dissolved. Adjust the pH to 6.8, filter, and sterilize at 121℃ for 15min to obtain the culture medium.

[0072] S2. Saccharomyces cerevisiae, ester-producing yeast, Bifidobacterium longum, and Lactobacillus rhamnosus were activated in sterile culture medium at 37°C for 24 h, then centrifuged at 5000 rpm for 20 min, the supernatant was discarded, the bacterial cells were collected, and bacterial suspensions were prepared with sterile water to obtain Saccharomyces cerevisiae suspension, ester-producing yeast suspension, Bifidobacterium longum suspension, and Lactobacillus rhamnosus suspension, respectively. Then, 15 g of Saccharomyces cerevisiae suspension, 12 g of ester-producing yeast suspension, 5 g of Bifidobacterium longum suspension, and 7 g of Lactobacillus rhamnosus suspension were mixed to obtain microbial composition A.

[0073] S3. Lactobacillus acidophilus and Bacillus lysine were activated in sterile culture medium at 37°C for 24 h, then centrifuged at 5000 rpm for 20 min, the supernatant was discarded, the bacterial cells were collected, and bacterial suspensions were prepared with sterile water to obtain Lactobacillus acidophilus suspension and Bacillus lysine suspension respectively. Then, 14 g of Lactobacillus acidophilus suspension and 9 g of Bacillus lysine suspension were mixed to obtain microbial composition B;

[0074] S4. Take 30g of wheat, spray it with water to moisten it, crush it, mix it with 25g of fresh wheat bran, 12g of kudzu root powder and 9g of inulin, add water, mix the mixture evenly, and then divide it into Erlenmeyer flasks. The thickness of the filling should not exceed 2cm. Wrap the flasks with 8 layers of gauze and seal them. Then wrap them with kraft paper for sterilization. Place them in a sterile room and wait for them to cool to 30°C. Use an inoculation loop to pick up the mold spores of Rhizopus nigricans and Rhizopus oryzae and inoculate them into the Erlenmeyer flasks respectively. Mix them well and place them in a 30°C incubator for 48h. When the surface of the bran is covered with mycelium, invert the flasks and incubate for 6 days. Dry them at 40°C for 5h. Mix 15g of Rhizopus nigricans and 7g of Rhizopus oryzae to obtain the mother koji and store it at 4°C.

[0075] S5. Crush 50g of rice, 88g of sorghum and 28g of glutinous rice and mix them together. Soak them in 75℃ hot water for 11 hours. After draining, steam the mixture for 45 minutes and spread it out to cool to obtain the cooked mixture.

[0076] S6. Mix 120g of mother koji and 30g of microbial composition B evenly to obtain small koji. Then, sprinkle 0.6g of small koji on 12g of cooked material in 5 portions and mix evenly. Keep warm and pile up to obtain saccharified cooked material.

[0077] S7. Mix 10g of saccharified cooked material and 0.5g of microbial composition A evenly, put them into a fermentation pit for fermentation, and distill at 85℃ for 55 minutes to obtain baijiu (Chinese liquor).

[0078] S8. Mix 50g of the distilled liquor with 0.03g of microbial composition A to obtain an aging and fermentation mixture for aging. Then, purify the mixture with oxygen for 5 hours a day for 24 consecutive days to obtain high-quality liquor.

[0079] Comparative Example 1:

[0080] Compared with Example 1, this comparative example did not add microbial composition A during the preparation of baijiu. All other steps and parameters were the same, and will not be repeated here. The final result was high-quality baijiu.

[0081] Comparative Example 2:

[0082] Compared with Example 1, this comparative example did not add microbial composition B during the preparation of baijiu. All other steps and parameters were the same, and will not be repeated here. The final result was high-quality baijiu.

[0083] Comparative Example 3:

[0084] Compared with Example 1, this comparative example did not add inulin during the preparation of baijiu. All other steps and parameters were the same, and will not be repeated here. The final result was high-quality baijiu.

[0085] Comparative Example 4:

[0086] This comparative example differs from Example 1 only in that the microbial composition A is replaced with brewer's yeast; all other steps and parameters are the same. This comparative example will not be repeated here, and the final result is a high-quality baijiu.

[0087] Comparative Example 5:

[0088] Compared with Example 1, this comparative example only replaces 10g of Saccharomyces cerevisiae suspension, 8g of ester-producing yeast suspension, 2g of Bifidobacterium longum suspension, and 4g of Lactobacillus rhamnosus suspension with 10g of Saccharomyces cerevisiae suspension, 10g of ester-producing yeast suspension, 10g of Bifidobacterium longum suspension, and 10g of Lactobacillus rhamnosus suspension. All other steps and parameters are the same, and will not be repeated in this comparative example. The final result is high-quality baijiu.

[0089] Performance testing:

[0090] Total acid content:

[0091] Preparation of 0.1 mol / L NaOH solution: Weigh 2 g of sodium hydroxide into a dry small beaker, place it in the beaker, dissolve it in water and dilute it to 500 mL to prepare a solution, store it in a narrow-mouthed bottle with a rubber stopper, and shake well.

[0092] Standardization of NaOH standard solution concentration: Accurately weigh 0.6 g of potassium hydrogen phthalate (pre-dried at 120℃ for 2 hours) into a 250 mL Erlenmeyer flask, dissolve in 50 mL of water, then add 2 drops of 0.1% phenolphthalein indicator. Titrate with 0.1 mol / L NaOH standard solution until a faint pink color persists for half a minute; this is the endpoint. (Note: The relative average deviation of the three determinations should be less than 0.2%; otherwise, a thorough determination is necessary.)

[0093] Total acid content determination: Take 50.0 mL of the liquor prepared in Examples 1-3 and Comparative Examples 1-5 into a 250 mL Erlenmeyer flask, add 100 mL of distilled water and 2 drops of phenolphthalein indicator, titrate with 0.1 oz / sodium hydroxide standard solution until a faint red color appears, which is the endpoint, and record the volume of standard solution consumed. Perform 4 parallel titrations.

[0094] Total acid calculation formula:

[0095] X= 1000

[0096] X - Total acid content in the wine sample (calculated as acetic acid), g / L; C - Concentration of sodium hydroxide standard solution, mol / L; V - Volume of sodium hydroxide standard solution consumed during the determination, mL;

[0097] 0.0601-1.00 mL sodium hydroxide standard solution [CNaOH) = 1.000 mol / L]: equivalent mass of acetic acid in grams (g); 50.0 - sample volume, mL;

[0098] 2. Total ester content

[0099] Preparation of 0.1 mol / L hydrochloric acid: Measure 4.7 mL of concentrated hydrochloric acid using a graduated cylinder and dilute with water to 500 mL;

[0100] Standardization of NaOH standard solution concentration: Accurately transfer 25 mL of hydrochloric acid standard solution into a 250 mL Erlenmeyer flask, add 2 drops of phenolphthalein indicator, and titrate with NaOH standard solution until a faint pink color remains for half a minute, which is the endpoint. The relative average deviation of the three determinations should be less than 0.2%; otherwise, a more thorough determination should be performed.

[0101] Total ester content determination: Take 50.00 mL of the liquor samples prepared in Examples 1-3 and Comparative Examples 1-5 into 250 mL Erlenmeyer flasks, add 2 drops of 0.1% phenolphthalein indicator, and titrate with 0.1 mol / L sodium hydroxide standard solution until a faint pink color appears (do not add excess). Record the volume fraction (mL) of sodium hydroxide standard solution consumed. Then accurately add 25.0 mL of 0.1 mol / L sodium hydroxide standard solution, attach a condenser, and reflux in a boiling water bath for half an hour for saponification. Remove and cool, then back titrate with 0.1 mol / L sulfuric acid standard solution until the faint pink color just disappears completely. Record the volume of 0.1 mol / L sulfuric acid standard solution consumed. Perform four parallel titrations.

[0102] Formula for calculating total esters:

[0103] X= 1000

[0104] In the formula, X represents the total ester content (calculated as ethyl acetate) in the wine sample, g / L; C represents the concentration of sodium hydroxide standard solution, mol / L; 25.0 represents the volume of 0.1 mol / L sodium hydroxide standard solution added during saponification, mL; C1 represents the concentration of sulfuric acid standard solution, mol / L; V represents the volume of 0.1 mol / L sulfuric acid standard solution consumed during the determination, mL; 0.088 and 1.00 mL of sodium hydroxide standard solution [C(NaOH) = 1.000 mol / L]; the equivalent mass of ethyl acetate expressed in grams (g); and 50.0 represents the sampling volume, mL.

[0105] Determination of solid content:

[0106] Take 50 mL of the baijiu prepared in Examples 1-3 and Comparative Examples 1-5 respectively, and pour it into a 100 mL porcelain evaporating dish that has been dried to constant weight. Evaporate to dryness in a boiling water bath. Then dry in an oven at 100-105℃ for 2 hours. Remove and cool in a desiccator for 30 minutes, then weigh. Dry for another hour, cool in a desiccator for 30 minutes, then weigh. Repeat the above operation until constant weight is achieved.

[0107] The formula for calculating solids is as follows:

[0108] Solid content (g / L) = (m-m1)(1 / 50)1000;

[0109] In the formula, m is the mass of the solid and the evaporating dish, g; m1 is the mass of the evaporating dish, g; and 50 is the sampling volume, mL.

[0110] Sensory evaluation:

[0111] The sensory evaluation standard was based on the sensory requirements of high-proof liquor in the GB / T26760-2011 test standard. The evaluation was conducted from four aspects: color and appearance, aroma, taste and style. The evaluators consisted of national and provincial-level liquor judges. Each liquor sample was evaluated by three evaluators in three separate evaluations. The sensory evaluation of the liquors prepared in Examples 1-3 and Comparative Examples 1-5 was recorded in accordance with the sensory evaluation standard.

[0112] Table 1

[0113]

[0114] Table 2 Sensory Evaluation Criteria

[0115]

[0116] Table 3 Sensory Evaluation Results

[0117]

[0118] Data Analysis:

[0119] As can be seen from Tables 1-3, the baijiu prepared by this invention has higher total acid and total ester content and sensory evaluation. This may be because the koji is prepared by the mother koji and microbial composition B. Puerarin and inulin in the mother koji can enhance the activity of microorganisms and improve the microbial community structure. Lactobacillus acidophilus in microbial composition B can degrade inulin to release fructose and convert it into lactic acid and acetic acid, providing organic acids for the subsequent esterification reaction. At the same time, Bacillus lysine in microbial composition B can effectively degrade lactic acid, avoiding excessive acid content from affecting the later fermentation. The synergistic effect of the mother koji and microbial composition B further improves the quality of baijiu. After saccharification, rice, sorghum, etc., under the action of brewing yeast and ester-producing yeast in microbial composition A, produce acids and esters. The probiotics Bifidobacterium longum and Lactobacillus rhamnosus can produce beneficial substances such as enzymes and short-chain fatty acids through metabolism, increasing the aroma and taste of the liquor, inhibiting the growth of harmful microorganisms, and thus improving the quality of the liquor. The four microorganisms in microbial composition A are mixed in a specific ratio, which is conducive to the generation of a large number of aroma substances, improving the quality of baijiu and shortening the brewing time.

[0120] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

[0121] This invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for improving the quality of baijiu (Chinese liquor) using microbial communities, characterized in that, Includes the following steps: Step S1. Grind the rice, sorghum and glutinous rice, mix them together, soak them in hot water, drain them, steam them and spread them out to cool to obtain the cooked mixture. Step S2. Sprinkle the koji into the cooked material in 5 batches and mix evenly. Keep warm and pile up to obtain the saccharified cooked material. Step S3. After mixing the saccharified cooked material and microbial composition A evenly, put it into a fermentation pit for fermentation, and then distill it to obtain baijiu (Chinese liquor); Step S4. Mix the distilled liquor with microbial composition A to obtain an aging and fermentation mixture for aging. Then, purify the mixture with oxygen for 2-5 hours per day for 16-24 days to obtain high-quality liquor. The small starter culture mentioned in step S2 is prepared by mixing the mother starter culture and microbial composition B at a mass ratio of 100-120:22-30; The microbial composition B was prepared from Lactobacillus acidophilus and Bacillus lysine. The microbial composition A described in step S3 is prepared from Saccharomyces cerevisiae, ester-producing yeast, Bifidobacterium longum, and Lactobacillus rhamnosus.

2. The method for improving the quality of baijiu (Chinese liquor) using microbial communities according to claim 1, characterized in that, The mass ratio of rice, sorghum, and glutinous rice in step S1 is 35-50:62-88:13-28; The temperature of the hot water is 60-75℃, and the soaking time is 8-11 hours; The steaming time is 35-45 minutes.

3. The method for improving the quality of baijiu (Chinese liquor) using microbial communities according to claim 1, characterized in that, The method for preparing the master koji is as follows: Take wheat, spray it with water to moisten it, then crush it and mix it with fresh wheat bran, kudzu root powder and inulin. Add water and mix well. Then divide it into Erlenmeyer flasks, with the filling thickness not exceeding 2cm. Wrap the flasks with 8 layers of gauze and seal them. Then wrap them with kraft paper for sterilization and place them in a sterile room. When the temperature drops to 30°C, use an inoculation loop to pick up mold spores of Rhizopus nigricans and Rhizopus oryzae and inoculate them into the Erlenmeyer flasks respectively. After mixing well, place them in an incubator at 28-30°C for 46-48 hours. When the surface of the bran is covered with mycelium, invert the flasks and incubate for 5-6 days. After drying and mixing, the mother koji is obtained and stored at 4°C.

4. The method for improving the quality of baijiu (Chinese liquor) using microbial communities according to claim 3, characterized in that, The mass ratio of wheat, fresh wheat bran, kudzu root powder and inulin is 22-30:18-25:8-12:6-9; The drying temperature is 35-40°C and the time is 4-5 hours. The mass ratio of Rhizopus nigricans to Rhizopus oryzae during the mixing process is 9-15:4-7.

5. The method for improving the quality of baijiu (Chinese liquor) using microbial communities according to claim 1, characterized in that, The preparation method of the microbial composition B is as follows: Lactobacillus acidophilus and Bacillus lysine were activated in sterile culture medium at 37°C for 22-24 hours, then centrifuged at 4000-5000 rpm for 15-20 minutes. The supernatant was discarded, the bacterial cells were collected, and bacterial suspensions were prepared with sterile water to obtain Lactobacillus acidophilus suspension and Bacillus lysine suspension respectively. The Lactobacillus acidophilus suspension and Bacillus lysine suspension were then mixed to obtain microbial composition B.

6. The method for improving the quality of Baijiu (Chinese liquor) using microbial communities according to claim 5, characterized in that, The culture medium formula is as follows: 10g peptone, 10g beef extract, 5g yeast extract, 20g glucose, 1mL Tween-80, 2g diammonium hydrogen citrate, 5g sodium acetate, 2g dipotassium hydrogen phosphate, 0.58g magnesium sulfate heptahydrate, 0.25g manganese sulfate tetrahydrate, 1000mL distilled water, pH 6.8; The mass ratio of the Lactobacillus acidophilus suspension to the Bacillus lysine suspension is 8-14:5-9; The viable count of Lactobacillus acidophilus in the microbial composition B is 110. 8 -110 10 CFU / g, viable count of Bacillus lysine is 1 x 10⁻⁶. 6 -10 8 CFU / g.

7. The method for improving the quality of Baijiu (Chinese liquor) using microbial communities according to claim 1, characterized in that, The preparation method of the microbial composition A is as follows: Saccharomyces cerevisiae, ester-producing yeast, Bifidobacterium longum, and Lactobacillus rhamnosus were activated in sterile culture medium at 37°C for 22-24 hours, then centrifuged at 4000-5000 rpm for 15-20 minutes. The supernatant was discarded, the bacterial cells were collected, and bacterial suspensions were prepared with sterile water to obtain Saccharomyces cerevisiae, ester-producing yeast, Bifidobacterium longum, and Lactobacillus rhamnosus bacterial suspensions, respectively. The Saccharomyces cerevisiae, ester-producing yeast, Bifidobacterium longum, and Lactobacillus rhamnosus bacterial suspensions were then mixed to obtain microbial composition A.

8. The method for improving the quality of baijiu (Chinese liquor) using microbial communities according to claim 7, characterized in that, The mass ratio of the Saccharomyces cerevisiae suspension, the ester-producing yeast suspension, the Bifidobacterium longum suspension, and the Lactobacillus rhamnosus suspension is 10-15:8-12:2-5:4-7. The viable count of the Saccharomyces cerevisiae suspension in the microbial composition A is 510. 8 -510 10 CFU / mL, viable count of ester-producing yeast suspension was 310. 7 -310 9 The CFU / mL count of Bifidobacterium longum was 2.

210. 7 -2.210 10 CFU / mL, viable count of Lactobacillus rhamnosus was 210. 7 -210 8 CFU / mL.

9. The method for improving the quality of Baijiu (Chinese liquor) using microbial communities according to claim 1, characterized in that, The mass ratio of koji and clinker in step S2 is 0.4-0.6:9-12; The mass ratio of the saccharified cooked material and the microbial composition A in step S3 is 8-10:0.2-0.

5.

10. The method for improving the quality of baijiu (Chinese liquor) using microbial communities according to claim 1, characterized in that, The distillation temperature in step S3 is 78-85℃, and the time is 40-55 min; The mass ratio of the distilled liquor and the microbial composition A obtained in step S4 is 40-50:0.01-0.03.

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