Microbial liquid for improving quality of Maotai-flavor liquor and application of microbial liquid

Abstract

The invention relates to the technical field of wine brewing, and particularly discloses a microbial liquid for improving the quality of Maotai-flavor liquor and application thereof.Through the synergistic effect of three microbial agents, a continuous metabolic complementary network is formed in a brewing system, and clostridium tyrobutyricum provides organic acid and part of precursor substances in the anaerobic stage; the issatchenkia orientalis dominates alcoholic fermentation and synthesis of main esters, and creates a chemical environment beneficial to metabolism of other strains; the staphylococcus saprophyticus enhances protein conversion and generation of special flavor substances. According to the method, the metabolic pathways of acids, esters, pyrazines and phenols in a brewing system are enhanced, so that key flavor substances of the Maotai-flavor liquor are systematically improved, the fragrance of the liquor body is stronger and more harmonious, the taste is more mellow and full, and the overall quality is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of brewing technology, specifically to a microbial inoculum for improving the quality of Maotai-flavor liquor and its application. Background Technology

[0002] Baijiu, one of the world's most famous distilled spirits, is renowned for its complex production process and unique flavor profile. Traditional baijiu, especially Chinese baijiu, is primarily brewed using solid-state fermentation. Its production process involves multiple stages, including koji making, fermentation, distillation, and aging, ultimately resulting in a spirit with a strong regional character and rich layers of aroma. Among these, sauce-aroma baijiu is a typical example, characterized by its long brewing cycle, meticulous craftsmanship, and flavor profile known for its prominent sauce aroma, elegant and delicate character, mellow body, and long-lasting aftertaste.

[0003] In the traditional baijiu brewing system, microorganisms play a crucial role, their activities permeating the entire biochemical process from koji making to fermentation. The flavor of baijiu is essentially a product of microbial metabolic activity. During koji making, the raw materials are naturally inoculated in an open environment, accumulating various microorganisms such as molds, yeasts, and bacteria from the air, water sources, and the production environment. The various enzyme systems secreted by these microorganisms provide crucial catalytic power for subsequent fermentation. Once fermentation begins, microorganisms, through cooperation and competition, sequentially carry out starch saccharification, alcoholic fermentation of sugars, and a series of complex secondary metabolic reactions, generating ethanol, which forms the backbone of baijiu, as well as hundreds of trace components that determine its flavor profile, such as esters, acids, alcohols, and aromatic compounds. Therefore, the composition, succession patterns, and metabolic stability of microorganisms directly determine the yield, typical style, and final quality of baijiu. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a microbial inoculum for improving the quality of Maotai-flavor liquor and its application.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a microbial culture solution for improving the quality of Maotai-flavor liquor, wherein the microbial culture solution includes Clostridium butyricum culture solution, Saccharomyces orientalis culture solution and Staphylococcus saprophyticus culture solution.

[0006] In the technical solution disclosed in this invention, the volume ratio of Clostridium butyricum liquid, Saccharomyces orientalis liquid and Staphylococcus saprophyticus liquid is 1-2:1-2:1-3.

[0007] In the technical solution disclosed in this invention, the effective viable count of Clostridium butyricum in the bacterial solution is ≥1.0×10⁻⁶. 8 CFU / mL.

[0008] In the technical solution disclosed in this invention, the effective viable cell count in the *Issa mesasura* broth is ≥1.0 × 10⁻⁶. 8 CFU / mL.

[0009] In the technical solution disclosed in this invention, the effective viable count of the *Staphylococcus saprophyticus* bacterial solution is ≥1.0 × 10⁻⁶. 9 CFU / mL.

[0010] This invention provides the application of the above-mentioned microbial inoculum in the brewing of Maotai-flavor liquor.

[0011] This invention provides the application of the above-mentioned microbial inoculum in the in-situ fermentation of Maotai-flavor liquor.

[0012] This invention also provides a method for in-situ fermentation of soy sauce-flavored liquor using the above-mentioned microbial inoculum, comprising the following steps: Sorghum, wheat and glutinous rice are crushed and mixed to obtain a mixture. The mixture is then placed in hot water at a temperature of 50-80℃ and soaked for 115 hours. After draining, the mixture is steamed and then spread out to cool to obtain cooked material. Add the starter culture to the cooled cooked material, mix well, then spray the microbial liquid evenly onto the cooked material, stir and mix well, and carry out co-fermentation at 28℃-35℃ for 30-35 days to obtain fermented mash. Distilling the fermented mash in a still yields a sauce-flavored baijiu.

[0013] In the technical solution disclosed in this invention, the amount of Daqu (a type of starter culture) added is 6-8% of the weight of the clinker.

[0014] In the technical solution disclosed in this invention, the ratio of microbial inoculum to cooked material is 5-10 mL / kg.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) The microbial inoculum provided by this invention includes Clostridium butyricum inoculum, Isaac's yeast inoculum, and Staphylococcus saprophyticus inoculum. In the in-situ fermentation of Maotai-flavor liquor, Clostridium butyricum can convert complex carbohydrates in the raw materials into short-chain fatty acids such as butyric acid and acetic acid. These organic acids are not only important components of the liquor's skeleton, but also indispensable precursors for ester synthesis. Isaac's yeast inoculum can efficiently convert sugars into ethanol and produce abundant extracellular enzymes. Its main function is reflected in ester synthesis, especially the production of ethyl acetate. Isaac's yeast inoculum can utilize the environment Acetic acid (including that produced by Clostridium butyricum, etc.) combines with ethanol under the catalysis of esterase, significantly increasing the content of ethyl acetate in the wine, thus giving the wine a prominent aroma. At the same time, its metabolites and the amino acids, nucleotides and other substances released after autolysis provide a rich nutrient matrix for the growth of other microorganisms and the further transformation of flavor substances. The proteases secreted by Staphylococcus saprophyticus can effectively degrade the proteins in the raw materials to generate polypeptides and free amino acids. These amino acids can provide nitrogen source for yeast growth, and at the same time promote the large-scale production of tetramethylpyrazine, which strengthens the soy sauce aroma characteristics of the wine.

[0016] (2) This invention, through the synergistic effect of three microbial agents, forms a continuous metabolic complementary network in the brewing system. Clostridium butyricum provides organic acids and some precursor substances during the anaerobic stage; Isaac's orientalis dominates alcoholic fermentation and the synthesis of the main esters, and creates a chemical environment conducive to the metabolism of other microbial species; Staphylococcus saprophyticus enhances protein conversion and the generation of special flavor substances. By strengthening the metabolic pathways of acids, esters, pyrazines, and phenols in the brewing system, this invention achieves a systematic enhancement of key flavor substances in soy sauce-flavored baijiu, making the aroma of the liquor more intense and harmonious, the taste more mellow and full-bodied, and the overall quality significantly improved. Detailed Implementation

[0017] The present invention will be further described in detail below through specific preferred embodiments, but the present invention is not limited to the following embodiments.

[0018] It should be noted that, unless otherwise specified, all chemical reagents involved in this invention were purchased through commercial channels.

[0019] Clostridium butyricum strain number: CICC 24498, purchased from China Industrial Microbial Culture Collection Center; The strain number of *Issa mesasura* is SHBCC D81776, purchased from Shanghai Center for Preservation of Biotechnology. The strain number of *Staphylococcus saprophyticus* was CICC 24370, purchased from the China Industrial Microbial Culture Collection Center. The effective viable count in the Clostridium butyricum culture was 1.0 × 10⁻⁶. 8 CFU / mL; The effective viable cell count in the *Issa mesasura* culture was 1.0 × 10⁻⁶. 8 CFU / mL; The effective viable count in the Staphylococcus saprophyticus bacterial solution was 1.0 × 10⁻⁶. 9 CFU / mL.

[0020] Example 1 A method for in-situ fermentation of Maotai-flavor liquor using microbial inoculum includes the following steps: After crushing sorghum, wheat and glutinous rice, they are mixed in a mass ratio of 50:35:15 to obtain a mixture. The mixture is then placed in hot water at 60℃ and soaked for 8 hours. After draining, it is steamed for 30 minutes and then spread out to cool to obtain cooked material. Daqu (a type of starter culture) is added to the cooled cooked material at a rate of 6% of the weight of the cooked material. The mixture is then thoroughly mixed. Microbial inoculum is then evenly sprayed onto the cooked material at a ratio of 8 mL / kg of microbial inoculum to cooked material. The mixture is stirred and thoroughly mixed, and then co-fermented at 30°C for 32 days to obtain fermented mash. The volume ratio of Clostridium butyricum, Isaac's orientalis, and Staphylococcus saprophyticus in the microbial inoculum was 1:1:2. Distilling the fermented mash in a still yields a sauce-flavored baijiu.

[0021] Example 2 A method for in-situ fermentation of Maotai-flavor liquor using microbial inoculum includes the following steps: After crushing sorghum, wheat and glutinous rice, they are mixed in a mass ratio of 50:35:15 to obtain a mixture. The mixture is then placed in hot water at 60℃ and soaked for 8 hours. After draining, it is steamed for 30 minutes and then spread out to cool to obtain cooked material. Daqu (a type of starter culture) is added to the cooled cooked material at a rate of 8% of the weight of the cooked material. The mixture is then thoroughly mixed. Microbial inoculum is then evenly sprayed onto the cooked material at a ratio of 5 mL / kg. The mixture is stirred and thoroughly mixed, and then co-fermented at 30°C for 32 days to obtain fermented mash. The volume ratio of Clostridium butyricum, Isaac's yeast, and Staphylococcus saprophyticus in the microbial inoculum was 1:1:2. Distilling the fermented mash in a still yields a sauce-flavored baijiu.

[0022] Example 3 A method for in-situ fermentation of Maotai-flavor liquor using microbial inoculum includes the following steps: After crushing sorghum, wheat and glutinous rice, they are mixed in a mass ratio of 50:35:15 to obtain a mixture. The mixture is then placed in hot water at 60℃ and soaked for 8 hours. After draining, it is steamed for 30 minutes and then spread out to cool to obtain cooked material. Add Daqu (a type of starter culture) to the cooled cooked material at a rate of 7% of the cooked material weight. Mix well, then spray the microbial inoculum evenly onto the cooked material at a ratio of 10 mL / kg. Stir and mix well, and then co-ferment at 30°C for 32 days to obtain fermented mash. The volume ratio of Clostridium butyricum, Isaac's yeast, and Staphylococcus saprophyticus in the microbial culture was 1:2:2. Distilling the fermented mash in a still yields a sauce-flavored baijiu.

[0023] Example 4 A method for in-situ fermentation of Maotai-flavor liquor using microbial inoculum includes the following steps: After crushing sorghum, wheat and glutinous rice, they are mixed in a mass ratio of 50:25:25 to obtain a mixture. The mixture is then placed in hot water at 60℃ and soaked for 8 hours. After draining, it is steamed for 30 minutes and then spread out to cool to obtain cooked material. Daqu (a type of starter culture) is added to the cooled cooked material at a rate of 6% of the weight of the cooked material. The mixture is then thoroughly mixed. Microbial inoculum is then evenly sprayed onto the cooked material at a ratio of 8 mL / kg of microbial inoculum to cooked material. The mixture is stirred and thoroughly mixed, and then co-fermented at 30°C for 32 days to obtain fermented mash. The volume ratio of Clostridium butyricum, Isaac's orientalis, and Staphylococcus saprophyticus in the microbial culture was 1:1:3. Distilling the fermented mash in a still yields a sauce-flavored baijiu.

[0024] Comparative Example 1 A method for in-situ fermentation of Maotai-flavor liquor using microbial inoculum includes the following steps: After crushing sorghum, wheat and glutinous rice, they are mixed in a mass ratio of 50:35:15 to obtain a mixture. The mixture is then placed in hot water at 60℃ and soaked for 8 hours. After draining, it is steamed for 30 minutes and then spread out to cool to obtain cooked material. Daqu (a type of starter culture) is added to the cooled cooked material at a rate of 6% of the weight of the cooked material. The mixture is then thoroughly mixed and fermented at 30°C for 32 days to obtain fermented mash. Distilling the fermented mash in a still yields a sauce-flavored baijiu.

[0025] Compared with Example 1, no microbial culture was introduced into Comparative Example 1.

[0026] Comparative Example 2 A method for in-situ fermentation of Maotai-flavor liquor using microbial inoculum includes the following steps: After crushing sorghum, wheat and glutinous rice, they are mixed in a mass ratio of 50:35:15 to obtain a mixture. The mixture is then placed in hot water at 60℃ and soaked for 8 hours. After draining, it is steamed for 30 minutes and then spread out to cool to obtain cooked material. Daqu (a type of starter culture) is added to the cooled cooked material at a rate of 6% of the weight of the cooked material. The mixture is then thoroughly mixed. Microbial inoculum is then evenly sprayed onto the cooked material at a ratio of 8 mL / kg of microbial inoculum to cooked material. The mixture is stirred and thoroughly mixed, and then co-fermented at 30°C for 32 days to obtain fermented mash. The volume ratio of Clostridium butyricum culture and Staphylococcus saprophyticus culture in the microbial culture was 1:2; Distilling the fermented mash in a still yields a sauce-flavored baijiu.

[0027] Compared with Example 1, Comparative Example 2 did not contain Saccharomyces orientalis in the microbial culture.

[0028] Comparative Example 3 A method for in-situ fermentation of Maotai-flavor liquor using microbial inoculum includes the following steps: After crushing sorghum, wheat and glutinous rice, they are mixed in a mass ratio of 50:35:15 to obtain a mixture. The mixture is then placed in hot water at 60℃ and soaked for 8 hours. After draining, it is steamed for 30 minutes and then spread out to cool to obtain cooked material. Daqu (a type of starter culture) is added to the cooled cooked material at a rate of 6% of the weight of the cooked material. The mixture is then thoroughly mixed. Microbial inoculum is then evenly sprayed onto the cooked material at a ratio of 8 mL / kg of microbial inoculum to cooked material. The mixture is stirred and thoroughly mixed, and then co-fermented at 30°C for 32 days to obtain fermented mash. The volume ratio of Clostridium butyricum culture and Isaac's yeast culture in the microbial culture was 1:2; Distilling the fermented mash in a still yields a sauce-flavored baijiu.

[0029] Compared with Example 1, Comparative Example 3 did not contain Staphylococcus saprophyticus in the microbial culture.

[0030] Comparative Example 4 A method for in-situ fermentation of Maotai-flavor liquor using microbial inoculum includes the following steps: After crushing sorghum, wheat and glutinous rice, they are mixed in a mass ratio of 50:35:15 to obtain a mixture. The mixture is then placed in hot water at 60℃ and soaked for 8 hours. After draining, it is steamed for 30 minutes and then spread out to cool to obtain cooked material. Daqu (a type of starter culture) is added to the cooled cooked material at a rate of 6% of the weight of the cooked material. The mixture is then thoroughly mixed. Microbial inoculum is then evenly sprayed onto the cooked material at a ratio of 8 mL / kg of microbial inoculum to cooked material. The mixture is stirred and thoroughly mixed, and then co-fermented at 30°C for 32 days to obtain fermented mash. The volume ratio of Clostridium butyricum, Isaac's yeast, and Bacillus licheniformis in the microbial culture was 1:1:2. Distilling the fermented mash in a still yields a sauce-flavored baijiu.

[0031] Compared with Example 1, Comparative Example 4 used Bacillus licheniformis instead of Staphylococcus saprophyticus. The strain number of Bacillus licheniformis was CGMCC No. 19753.

[0032] Comparative Example 5 A method for in-situ fermentation of Maotai-flavor liquor using microbial inoculum includes the following steps: After crushing sorghum, wheat and glutinous rice, they are mixed in a mass ratio of 50:35:15 to obtain a mixture. The mixture is then placed in hot water at 60℃ and soaked for 8 hours. After draining, it is steamed for 30 minutes and then spread out to cool to obtain cooked material. Daqu (a type of starter culture) is added to the cooled cooked material at a rate of 6% of the weight of the cooked material. The mixture is then thoroughly mixed. Microbial inoculum is then evenly sprayed onto the cooked material at a ratio of 8 mL / kg of microbial inoculum to cooked material. The mixture is stirred and thoroughly mixed, and then co-fermented at 30°C for 32 days to obtain fermented mash. The volume ratio of Clostridium butyricum, Isaac's yeast, and Bacillus subtilis in the microbial culture was 1:1:2. Distilling the fermented mash in a still yields a sauce-flavored baijiu.

[0033] Compared with Example 1, Comparative Example 5 uses Bacillus subtilis instead of Staphylococcus saprophyticus.

[0034] The contents of ethyl acetate, tetramethylpyrazine, and 4-methylguaiacol in the Maotai-flavor liquors of Examples 1-4 and Comparative Examples 1-5 were detected respectively, and the results are shown in Table 1.

[0035] Table 1. Test results of substance content in different groups Finally, it should be noted that the above embodiments do not limit the present invention in any way. Those skilled in the art can make modifications and improvements based on the present invention. Therefore, any modifications or improvements made without departing from the spirit of the present invention are within the scope of protection claimed by the present invention.

Claims

1. A microbial inoculum for improving the quality of Maotai-flavor liquor, characterized in that, The microbial inoculum includes Clostridium butyricum inoculum, Saccharomyces orientalis inoculum, and Staphylococcus saprophyticus inoculum.

2. The microbial inoculum according to claim 1, characterized in that, The volume ratio of the Clostridium butyricum culture, the Saccharomyces orientalis culture, and the Staphylococcus saprophyticus culture is 1-2:1-2:1-3.

3. The microbial inoculum solution according to claim 1, characterized in that, The effective viable count of Clostridium butyricum in the bacterial solution is ≥1.0×10⁻⁶. 8 CFU / mL.

4. The microbial inoculum according to claim 1, characterized in that, The effective viable cell count of the *Isabella orientalis* culture is ≥1.0 × 10⁻⁶. 8 CFU / mL.

5. The microbial inoculum according to claim 1, characterized in that, The effective viable count of the *Staphylococcus saprophyticus* bacterial solution is ≥1.0 × 10⁻⁶. 9 CFU / mL.

6. The application of the microbial inoculum as described in any one of claims 1-5 in the brewing of Maotai-flavor liquor.

7. The application of the microbial inoculum as described in any one of claims 1-5 in the in-situ fermentation of Maotai-flavor liquor.

8. A method for in-situ fermentation of soy sauce-flavored Baijiu using the microbial inoculum as described in any one of claims 1-5, characterized in that, Includes the following steps: Sorghum, wheat and glutinous rice are crushed and mixed to obtain a mixture. The mixture is then placed in hot water at a temperature of 50-80℃ and soaked for 115 hours. After draining, the mixture is steamed and then spread out to cool to obtain cooked material. Add the starter culture to the cooled cooked material, mix well, then spray the microbial liquid evenly onto the cooked material, stir and mix well, and carry out co-fermentation at 28℃-35℃ for 30-35 days to obtain fermented mash. Distilling the fermented mash in a still yields a sauce-flavored baijiu.

9. The method according to claim 8, characterized in that, The amount of Daqu (a type of starter culture) added is 6-8% of the weight of the clinker.

10. The method according to claim 8, characterized in that, The ratio of microbial inoculum to cooked food is 5-10 mL / kg.

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