Formula and brewing method of red sorghum multi-kou co-fermented green bean light-flavor liquor

Abstract

This invention discloses a formula and brewing method for a light-aroma baijiu made from red sorghum and mung beans through multi-fermentation. The method uses 75-85 parts red sorghum and 15-25 parts mung beans as raw materials. The mung beans are dehulled and pre-saccharified using low-temperature enzymatic hydrolysis, then mixed with red sorghum and subjected to high-temperature moistening and steaming for gelatinization. A light-aroma low-temperature koji is used as the base koji, combined with bran koji and enhanced functional koji (containing ester-producing yeast and aroma-producing yeast) to form a multi-fermentation agent. The total amount of koji used is 19-23% of the grain input. Fermentation takes place in earthen vats for 28 days, with the peak temperature controlled at 28-32℃ and the outlet temperature at 20-25℃. The base liquor is then aged in earthenware jars. This invention utilizes pre-saccharification of mung beans and multi-fermentation to achieve a harmonious blend of the characteristic aroma of mung beans and the aroma of Daqu (a type of starter culture). The finished wine has a total ester content of ≥2.0g / L and an ethyl acetate content of ≥1.2g / L. It is clear and transparent, mellow and sweet, with a natural mung bean aroma, high yield, stable process, and easy to scale up.

Description

Technical Field

[0001] This invention belongs to the field of liquor brewing technology, specifically relating to a formula and brewing method for a light-aroma liquor made from red sorghum and mung beans through multi-fermentation. Background Technology

[0002] Light-aroma baijiu holds an important position in my country's baijiu market due to its "clear, pure, sweet, clean, and lingering" characteristics. Traditional light-aroma baijiu is primarily made from sorghum, using low-temperature koji (fermentation starter) made from barley and peas as the saccharification and fermentation agent, and is brewed using a solid-state fermentation process in earthen vats. In recent years, to enrich the flavor profile, reduce raw material costs, or increase the yield, researchers have made numerous improvements to the raw material formula, types of koji used, and fermentation processes for light-aroma baijiu.

[0003] For example, Chinese invention patent CN120464458A discloses a formula and brewing method for using mung beans instead of peas to brew light-aroma baijiu. This method introduces mung beans to partially replace peas in the koji-making process (the koji contains 5-10% mung beans), utilizing the active ingredients such as arabinogalactan in mung beans to directionally enrich Bacteroidetes microorganisms, thereby optimizing the koji's microbial community ecological structure. This scheme mainly focuses on improving the koji-making process; its fermentation process still uses a single koji as the saccharification and fermentation agent, and the total fermentation cycle is as long as 25-35 days. It fails to achieve the synergistic effect of multiple koji blends and does not perform targeted pre-saccharification treatment on the mung bean raw material itself.

[0004] Chinese invention patent CN113549512A discloses a brewing process for a multi-grain solid-state light-aroma baijiu. This process adds 2 parts by weight of mung beans as brewing raw materials to a base of glutinous sorghum, rice, glutinous rice, corn, and wheat, and uses Rhizopus koji and Aspergillus koji as saccharification and fermentation agents. However, this method uses a relatively small amount of mung beans, mainly serving an auxiliary aroma-enhancing role. Furthermore, the fermentation container is an earthenware jar, the fermentation temperature is relatively high (35-38℃), and the fermentation cycle is long, lasting 30-50 days. This results in a light-aroma baijiu with a small-koji or mixed-koji style, exhibiting a significant difference in flavor characteristics compared to traditional large-koji light-aroma baijiu. Additionally, this method does not involve the compounding technology of multiple koji types (large-koji, bran koji, and functional microbial koji), nor does it perform low-temperature enzymatic pre-saccharification treatment on the mung beans, resulting in limited conversion efficiency of characteristic flavor precursors in the mung beans.

[0005] Chinese invention patent CN106479832A discloses a light-aroma baijiu made with bran koji and its production method. It uses bran koji, low-temperature daqu (large koji), yeast starter, and ester-producing yeast as a compound saccharification and fermentation agent, with sorghum as the raw material. This effectively increases the total ester content in the base liquor, improving the smoothness and elegance of the liquor. This method embodies the technical concept of multi-koji blending (daqu + bran koji + ester-producing yeast), but it does not introduce mung beans into the raw materials, resulting in a lack of the characteristic light aroma flavor brought by mung beans. Furthermore, its fermentation cycle is only 10-15 days, which, while improving production efficiency, somewhat limits the full generation of esters and the harmonious integration of flavors. Also, its sealed fermentation temperature (14-18℃) and fermentation temperature (20-30℃) differ from the earthen vat fermentation temperature control mode of this invention. Summary of the Invention

[0006] In view of the problems in the existing technology, such as insufficient transformation of mung bean flavor, poor synergy between multi-koji blend and mung bean raw material, and disconnect between the process and the core requirements of traditional light-aroma daqu baijiu, the present invention provides a brewing method for light-aroma baijiu made by co-fermenting mung beans with red sorghum and multi-koji.

[0007] This invention pre-saccharifies mung bean raw materials through low-temperature enzymatic hydrolysis, fully activating the endogenous enzyme system of mung beans and releasing flavor precursors. Simultaneously, the pre-treated mung beans are mixed with red sorghum in a specific ratio, incorporating traditional processes of high-temperature moistening and steaming for gelatinization. In the fermentation stage, a low-temperature, light-aroma Daqu (a type of starter culture) is used as the base, combined with bran Daqu and enhanced functional Daqu to construct a multi-Daqu co-fermentation system. Strict adherence to the 28-day solid-state fermentation standard in earthen vats achieves synergistic microbial metabolism between the characteristic light aroma of mung beans and the light aroma of Daqu at the fermentation level. During distillation, traditional operating procedures are followed, including observing the blooming of the liquor, removing the heads and tails, and slow distillation. The resulting base liquor possesses both the typical clear, clean, and refreshing style of light-aroma baijiu and the natural and elegant aroma of mung beans. Furthermore, the process is entirely based on existing production processes, making it highly practical.

[0008] This invention includes the following technical solutions: A brewing method for a light-aroma baijiu made from red sorghum and mung beans through multi-fermentation includes the following steps: S1: Raw material preparation and mung bean presaccharification Take 75-85 parts by weight of red sorghum and 15-25 parts by weight of mung beans. After dehulling the mung beans, perform low-temperature enzymatic hydrolysis and presaccharification treatment to obtain mung bean pretreated product. In the above scheme, low-temperature enzymatic hydrolysis and pre-saccharification is one of the key technologies of this invention. After dehulling, mung beans undergo low-temperature enzymatic hydrolysis, which allows the mung bean starch to be moderately decomposed into fermentable sugars under mild conditions using a compound enzyme preparation. At the same time, it releases flavor precursors such as arabinogalactan and vitexin, providing high-quality substrates for subsequent multi-fermentation.

[0009] S2: High-temperature moistening of millet The red sorghum and mung bean pretreatment materials are mixed and then moistened with boiling water at 96°C. The amount of water added is 55-65% of the total mass of the mixture to obtain moistened grain. In the above scheme, high-temperature soaking is a key process for removing impurities from raw materials and allowing starch to fully absorb water and swell in light-aroma baijiu. Using boiling water at 96℃ to soak the materials can effectively deactivate the lipoxygenase and other enzymes that produce a beany smell in mung beans, reducing the beany smell, while at the same time allowing the starch granules to quickly absorb water and swell.

[0010] S3: Steaming and gelatinizing After moistening, the rice is steamed and gelatinized, and then 21-23% of the steamed rice husks are added to obtain cooked rice. In the above scheme, the mash is steamed for 80 minutes after the gelatinization process, allowing the volatile off-flavor components in the mung beans to dissipate with the steam, while simultaneously achieving deep gelatinization of the starch. The steamed rice husks are then mixed with rice bran in a specific ratio to increase the looseness of the mash, providing a favorable physical structure for subsequent fermentation and distillation.

[0011] S4: Preparation of Multi-Kernel Fermentation Agent A multi-koji fermentation agent was prepared by using a light-aroma, low-temperature koji as the base koji, compounded with bran koji and enhanced functional koji; in the multi-koji fermentation agent, the base koji accounted for 60-70 wt%, the bran koji accounted for 20-25 wt%, and the enhanced functional koji accounted for 5-10 wt%; the total amount of koji used was 19-23% of the grain feed amount. In the above scheme, the multi-fermentation system is the core innovation that distinguishes this invention from existing single-fermentation methods. The light-aroma low-temperature koji is made from barley, peas, and mung beans using traditional techniques, providing abundant saccharifying enzymes, liquefying enzyme systems, and a basic flavor framework; the bran koji is rich in highly efficient saccharifying enzymes, which can improve the starch-to-alcohol yield; the enhanced functional koji contains ester-producing yeasts and aroma-producing yeasts, which metabolize synergistically during fermentation, efficiently converting mung bean precursors into characteristic aroma components, while increasing the total ester content of the liquor.

[0012] S5: Earthenware fermentation tank After the cooked grain is spread out to the temperature for entering the vat, the multi-koji fermentation agent is added and mixed evenly. The grain is then placed in a vat and sealed for fermentation. The fermentation cycle is 28 days, with the peak fermentation temperature controlled at 28-32℃ and the exit temperature at 20-25℃. In the above-mentioned scheme, fermentation in earthen vats is the core technological feature of light-aroma baijiu. The vats are buried underground, providing excellent heat retention, moisture control, and micro-permeability, while also preventing direct invasion by soil-borne microorganisms. The fermentation cycle is strictly controlled at 28 days, matching the growth and metabolic patterns of the microorganisms in the daqu (fermentation starter) and functional bacteria. The peak temperature of 28-32℃ is a typical characteristic temperature for low-temperature fermentation of light-aroma baijiu. Within this temperature range, multiple microbial species metabolize synergistically, ensuring both efficient alcohol fermentation and promoting the formation of flavor compounds such as esters.

[0013] S6: Distillation The fermented mash is loaded into a still for distillation. The beginning and end of the distillate are removed, and the middle section is collected to obtain the base liquor. In the above scheme, distillation follows the traditional operating procedures for light-aroma baijiu. The still is loaded using a "two-dry, one-wet, two-small-one-large-steam" loading method, with a loading time of 45-55 minutes, ensuring even distribution and appropriate density of the materials. Slow-fire distillation allows for the steady distillation of ethanol and aroma components from the mash. Eliminating the heads and tails effectively removes low-boiling-point irritating components such as methanol and aldehydes, as well as high-boiling-point fusel oils. The precise collection of the mid-section liquor, with an alcohol content of no less than 65% vol, is achieved through careful observation.

[0014] S7: Storage The base liquor is aged in a ceramic jar to obtain a light-aroma baijiu made from red sorghum and mung beans through multi-fermentation.

[0015] In the above method, the freshly distilled base spirit contains a certain amount of low-boiling-point irritating components, resulting in a relatively spicy taste. The earthenware jar has a microporous structure, allowing trace amounts of oxygen to slowly enter during aging, promoting the oxidation and esterification reactions of alcohols, aldehydes, and acids in the spirit, gradually making it mellow and smooth. At the same time, the metal ions in the earthenware jar have a catalytic effect on the aging process, contributing to the further integration and refinement of the mung bean aroma with the grain and yeast aromas.

[0016] Furthermore, in step S1, the low-temperature enzymatic hydrolysis and pre-saccharification treatment of mung beans includes: crushing the shelled mung beans to 40-80 mesh, adding 0.1-0.5% of a compound enzyme preparation by weight of the mung beans, and enzymatically hydrolyzing at 50-60℃ for 2-6 hours; the compound enzyme preparation contains α-amylase and saccharifying enzyme, with an enzyme activity ratio of 1:1 to 3:1.

[0017] Furthermore, in step S2, the high-temperature soaking time is 18-24 hours; in step S3, the conditions for steaming and gelatinization are: steaming the material for 80 minutes after steaming, the rice husks are pre-steamed for more than 30 minutes, and the rice husks contain rice bran accounting for 30% of their total mass.

[0018] Furthermore, in step S4, the light-aroma low-temperature koji is prepared by the following process: 55% barley, 35% peas, and 10% mung beans are weighed as koji-making raw materials according to weight percentage; the raw materials are mixed and crushed, passed through a 20-mesh sieve, and water of 38-42% of the total mass of the raw materials is added and mixed evenly; the koji is pressed into koji blocks, sent to the koji room for horizontal koji preparation, and cultivated at 20-25℃, going through stages of mold growth, mold drying, damp fire, high fire, and post-fire, with a total cultivation cycle of 28-32 days; after koji production, it is stored in the warehouse for more than 3 months.

[0019] Furthermore, in step S4, the enhanced functional koji is an ester-producing yeast koji, an aroma-producing yeast koji, or a mixture of both; in the enhanced functional koji, the colony count of the ester-producing yeast is 1×10⁻⁶. 8 ~5×10 8cfu / g, the colony count of aroma-producing yeast is 2×10⁻⁶. 8 ~1×10 9 cfu / g.

[0020] Furthermore, in step S5, the temperature of the fermentation tank is 13-17℃ in spring, autumn and winter, and 17-25℃ in summer; the sealed fermentation is carried out by covering the tank opening with a plastic film, and then sealing it with a tank gasket and a stone slab or cement board.

[0021] Furthermore, in step S6, the stilling adopts a "two dry, one wet, two small, one large steam" loading mode, with a loading time of 45-55 minutes. Among them, "two dry, one wet" means that a layer of wet mash is laid after every two layers of dry mash, and "two small, one large steam" means that a small steam pressure is used in the early and middle stages of loading, and a large steam pressure is used in the later stages of loading. The specific operation of extracting the middle section of the liquor is as follows: during the distillation process, observe the flow and collect the liquor. When the alcohol content of the liquor drops below 65% vol, stop collecting the middle section of the liquor, collect the tail liquor and return it to the still for re-distillation.

[0022] Furthermore, in step S7, the conditions for aging in the earthenware jars are as follows: the earthenware jars are sealed and aged for more than 6 months in an environment of 15-25℃ and relative humidity of 60-75%, and the wine is stored according to its quality.

[0023] A red sorghum multi-fermented mung bean-aroma baijiu produced by the brewing method described in any of the above technical solutions has a total ester content ≥2.0g / L, an ethyl acetate content ≥1.2g / L, and a characteristic mung bean aroma flavor derived from mung bean precursor substances. The liquor is clear and transparent, with a mellow and sweet taste and a clean aftertaste.

[0024] Compared with the prior art, the brewing method provided by the present invention has the following advantages: This invention employs a four-element synergistic system of "red sorghum skeleton + low-temperature Daqu base + multi-fermentation + mung bean aroma enhancement." Through low-temperature enzymatic pre-saccharification, mung bean flavor precursors are fully released. Then, through the synergistic metabolic transformation of multiple microorganisms (Daqu, bran koji, ester-producing yeast, and aroma-producing yeast), the conversion rate of characteristic mung bean flavor components is significantly higher than that of the direct crushing and fermentation method. The finished liquor has a natural mung bean aroma that blends harmoniously with the grain and koji aromas. The multi-koji compounding increases the starch alcohol yield, and the total ester content is more than 30% higher than the traditional single-koji process. The mung bean raw material undergoes dehulling, low-temperature enzymatic hydrolysis, and high-temperature moistening and steaming treatments, effectively removing the beany and off-flavors, and significantly reducing the fusel oil content of the base liquor. Continuous batch production trials show small batch-to-batch differences in alcohol content, total acid, total esters, and sensory scores, indicating good process stability. The entire brewing process relies on existing light-aroma baijiu production equipment and earthen vat fermentation system, requiring no major equipment modifications and making it suitable for large-scale promotion and application. Attached Figure Description

[0025] Figure 1This is a flowchart illustrating the brewing process of the red sorghum multi-fermentation mung bean light-aroma baijiu of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below. However, it should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention. Furthermore, descriptions of well-known technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of the invention. All raw materials used in the embodiments of this invention are commercially available.

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0028] The main raw material specifications used in the various embodiments and comparative examples of this invention are as follows.

[0029] Example 1 A type of light-aroma baijiu made from red sorghum fermented with multiple yeast starters and mung beans, comprising the following raw materials in parts by weight: 80 portions of red sorghum and 20 portions of mung beans; The mung beans undergo low-temperature enzymatic hydrolysis and presaccharification treatment, specifically including the following methods: (a) Grind the shelled mung beans to 60 mesh; (b) Add 0.3% of the mung bean mass of a compound enzyme preparation (the enzyme activity ratio of α-amylase to saccharifying enzyme is 2:1), and enzymatically hydrolyze in a water bath at 55°C for 4 hours to obtain the mung bean pretreated product; The preparation method of the light-aroma type low-temperature Daqu includes: Weigh out 55% barley, 35% peas, and 10% mung beans by weight percentage as raw materials for making koji; mix and grind them through a 20-mesh sieve, add water equal to 40% of the total mass of raw materials and mix evenly; press into koji blocks, send to the koji room to koji, and cultivate at 22℃, going through stages of mold growth, mold drying, damp fire, high fire, and post-fire, with a total cultivation cycle of 30 days; after koji is produced, store in the warehouse for 3 months; The multi-stage fermentation agent is formulated according to the following weight percentages: 65% light-aroma low-temperature koji, 22% wheat bran koji, and 13% enhanced functional koji; the enhanced functional koji is a mixture of ester-producing yeast koji and aroma-producing yeast koji, with an ester-producing yeast colony count of 3 × 10⁻⁶. 8 cfu / g, aroma-producing yeast colony count 6×10 8 cfu / g; like Figure 1 As shown, the brewing method of the red sorghum multi-fermentation mung bean light-aroma baijiu includes the following steps: S1: Take 80 parts of red sorghum and 20 parts of mung beans. After shelling the mung beans, perform low-temperature enzymatic hydrolysis and pre-saccharification treatment to obtain mung bean pretreatment product. S2: Mix red sorghum and mung bean pretreatment materials, and use boiling water at 96℃ for high-temperature moistening. The amount of water added is 60% of the total mass of the mixture. Moisten for 20 hours to obtain moistened grain. S3: Steam the moistened grain to gelatinize it. Steam the grain for 80 minutes after steaming. Add the steamed rice husks (rice husk to rice bran mass ratio 7:3) at 22% of the grain amount to obtain cooked grain. S4: Using light-aroma low-temperature Daqu as the base Daqu, combined with bran Daqu and enhanced functional bacteria Daqu, a multi-daqu fermentation agent was prepared, with the total amount of Daqu used being 21% of the grain feed amount; S5: Spread the cooked grain out to a temperature of 15℃ before entering the vat, add multi-koji fermentation agent and mix evenly, put it into a ground vat and seal it for fermentation for 28 days, controlling the fermentation peak temperature to 30℃ and the exit temperature to 22℃. S6: Take the fermented mash and load it into a still for distillation. The loading time is 50 minutes. Use slow fire distillation, observe the fermentation process, collect the liquor, and remove the head and tail. Select the middle section of liquor with an alcohol content of 65% vol. S7: Place the base liquor in a ceramic jar and age it for 6 months to obtain a light-aroma baijiu made from red sorghum and multiple yeasts.

[0030] Example 2 A type of light-aroma baijiu made from red sorghum fermented with multiple yeast starters and mung beans, comprising the following raw materials in parts by weight: 75 parts red sorghum, 25 parts mung beans; The mung beans undergo low-temperature enzymatic hydrolysis and presaccharification treatment, specifically including the following methods: (a) Grind the shelled mung beans to 40 mesh; (b) Add 0.5% of the mung bean mass of a compound enzyme preparation (the enzyme activity ratio of α-amylase to saccharifying enzyme is 1:1), and enzymatically hydrolyze in a water bath at 50°C for 6 hours to obtain the mung bean pretreated product; The preparation method of the light-aroma type low-temperature Daqu is the same as in Example 1; The multi-fermentation agent is formulated according to the following weight percentages: 60% light-aroma low-temperature koji, 25% wheat bran koji, and 15% enhanced functional koji; the enhanced functional koji is a mixture of ester-producing yeast koji and aroma-producing yeast koji, with an ester-producing yeast colony count of 1×10⁻⁶. 8 cfu / g, aroma-producing yeast colony count 2×10 8 cfu / g; The brewing method of the red sorghum multi-koji co-fermentation mung bean light aroma baijiu includes the following steps: S1: Take 75 parts of red sorghum and 25 parts of mung beans. After shelling the mung beans, perform low-temperature enzymatic hydrolysis and pre-saccharification treatment to obtain mung bean pretreatment product. S2: Mix red sorghum and mung bean pre-treated materials, and use boiling water at 96℃ to moisten the grits at high temperature. The amount of water added is 55% of the total mass of the mixture. Moisten for 24 hours to obtain moistened grits. S3: Steam the moistened grain to gelatinize it. Steam the grain for 80 minutes after steaming. Add the steamed rice husks (rice husk to rice bran mass ratio 7:3) at 21% of the grain amount to obtain cooked grain. S4: Using light-aroma low-temperature Daqu as the base Daqu, combined with bran Daqu and enhanced functional bacteria Daqu, a multi-daqu fermentation agent is prepared, with the total amount of Daqu used being 23% of the grain feed amount; S5: Spread the cooked grain out to a temperature of 13℃ before entering the vat, add multi-koji fermentation agent and mix evenly, put it into the ground vat and seal it for 28 days of fermentation, control the fermentation peak temperature to 28℃, and the exit temperature to 20℃. S6: Take the fermented mash and load it into a still for distillation. The loading time is 45 minutes. Use slow fire distillation, observe the fermentation process, collect the liquor, and remove the head and tail. Select the middle section of liquor with an alcohol content of 65% vol. S7: Place the base liquor in a ceramic jar and age it for 8 months to obtain a light-aroma baijiu made from red sorghum and multiple yeasts.

[0031] Example 3 A type of light-aroma baijiu made from red sorghum fermented with multiple yeast starters and mung beans, comprising the following raw materials in parts by weight: 85 parts red sorghum and 15 parts mung beans; The mung beans undergo low-temperature enzymatic hydrolysis and presaccharification treatment, specifically including the following methods: (a) Grind the shelled mung beans to 80 mesh; (b) Add 0.1% of the mung bean mass of a compound enzyme preparation (the enzyme activity ratio of α-amylase to saccharifying enzyme is 3:1), and enzymatically hydrolyze in a water bath at 60°C for 2 hours to obtain the mung bean pretreated product; The preparation method of the light-aroma type low-temperature Daqu is the same as in Example 1; The multi-fermentation agent is formulated according to the following weight percentages: 70% light-aroma low-temperature koji, 20% wheat bran koji, and 10% enhanced functional koji; the enhanced functional koji is a mixture of ester-producing yeast koji and aroma-producing yeast koji, with an ester-producing yeast colony count of 5 × 10⁻⁶. 8 cfu / g, aroma-producing yeast colony count 1×10 9 cfu / g; The brewing method of the red sorghum multi-koji co-fermentation mung bean light aroma baijiu includes the following steps: S1: Take 85 parts of red sorghum and 15 parts of mung beans. After shelling the mung beans, perform low-temperature enzymatic hydrolysis and presaccharification treatment to obtain mung bean pretreatment product. S2: Mix red sorghum and mung bean pretreatment materials, and use boiling water at 96℃ for high-temperature moistening. The amount of water added is 65% of the total mass of the mixture. Moisten for 18 hours to obtain moistened grain. S3: Steam the moistened grain to gelatinize it. Steam the material for 80 minutes after steaming. Add the steamed rice husks (rice husk to rice bran mass ratio 7:3) at 23% of the grain amount to obtain cooked grain. S4: Using light-aroma low-temperature Daqu as the base Daqu, combined with bran Daqu and enhanced functional bacteria Daqu, a multi-daqu fermentation agent was prepared, with the total amount of Daqu used being 19% of the grain feed amount; S5: Spread the cooked grain out to a temperature of 20℃ before it is put into the vat, add multi-koji fermentation agent and mix evenly, put it into the ground vat and seal it for fermentation for 28 days, controlling the fermentation peak temperature of 32℃ and the vat exit temperature of 25℃. S6: Take the fermented mash and load it into a still for distillation. The loading time is 55 minutes. Use slow fire distillation, observe the fermentation process, collect the liquor, and remove the head and tail. Select the middle section of liquor with an alcohol content of 65% vol. S7: The base liquor is aged in a ceramic jar for 12 months to obtain a light-aroma baijiu made from red sorghum and mung beans through multi-fermentation.

[0032] Comparative Example 1 A type of light-aroma baijiu made from red sorghum and mung beans, produced by weight of the following raw materials: 80 portions of red sorghum and 20 portions of mung beans; The mung beans are not subjected to low-temperature enzymatic hydrolysis and presaccharification treatment, but are directly crushed to 60 mesh and then mixed with red sorghum. The remaining steps are the same as in Example 1.

[0033] Comparative Example 2 A type of light-aroma baijiu made from red sorghum fermented with multiple yeast starters and mung beans, comprising the following raw materials in parts by weight: 80 portions of red sorghum and 20 portions of mung beans; The mung beans were subjected to low-temperature enzymatic hydrolysis and presaccharification treatment, the same as in Example 1; The fermenting agent is only a light-aroma type low-temperature Daqu, and the dosage is 21% of the grain feed. It does not contain bran koji or fortified functional bacteria koji. The remaining steps are the same as in Example 1.

[0034] Comparative Example 3 A type of light-aroma baijiu made from red sorghum fermented with multiple yeast starters and mung beans, comprising the following raw materials in parts by weight: 80 portions of red sorghum and 20 portions of mung beans; The mung beans were subjected to low-temperature enzymatic hydrolysis and presaccharification treatment, the same as in Example 1; The multi-stage fermentation agent is the same as in Example 1; The fermentation cycle in the earthen vat is 15 days, and the other conditions are the same as in Example 1.

[0035] Comparative Example 4 See CN120464458A.

[0036] A type of light-aroma baijiu made from red sorghum and mung beans, produced by weight of the following raw materials: 80 portions of red sorghum and 20 portions of mung beans; The mung beans were steamed at 105°C for 5 minutes to inactivate enzymes, then pulverized to 60 mesh and mixed with red sorghum. Use room temperature water (25℃) to moisten the grits, adding 60% of the total mass of the mixture, and moisten for 20 hours; After moistening, the grain is placed in a steamer and steamed at normal pressure for 60 minutes; The fermenting agent is only a light-aroma type of low-temperature Daqu (made from 62% barley, 33% peas, and 5% mung beans), and its dosage is 22% of the grain input. The fermentation cycle in the earthen vat is 25 days. The remaining steps are the same as in Example 1.

[0037] Test Example 1 Comparative Experiment of Physicochemical Indicators of Base Wine Objective: To verify the effect of the brewing method of the present invention on the main physicochemical indicators of the base wine.

[0038] Methods: Base liquors prepared in Examples 1-3 and Comparative Examples 1-4 were used. The alcohol content, total acidity, total esters, and ethyl acetate content were determined according to GB / T 10345-2007 "Analytical Methods for Baijiu"; the methanol content was determined according to GB 5009.266-2016; and the fusel oil content was determined according to GB / T 5009.48-2003. Each sample was measured in triplicate, and the average value was taken.

[0039] The results are shown in Table 1.

[0040] Table 1 Comparison of main physicochemical indicators of base liquor

[0041] The results showed that the total ester content of Examples 1-3 was between 2.79-2.91 g / L, and the ethyl acetate content was between 1.65-1.71 g / L, all meeting the requirements of the present invention of total ester ≥ 2.0 g / L and ethyl acetate ≥ 1.2 g / L. Example 3 had the highest total ester content (2.91 g / L), while Example 2 had the highest ethyl acetate content (1.71 g / L). Compared with Comparative Example 1 (mung beans without pre-saccharification), the total ester content of Examples 1-3 increased by an average of 20.6%; compared with Comparative Example 2 (using only koji), the average increase was 48.4%; compared with Comparative Example 3 (fermentation cycle of 15 days), the average increase was 58.6%; and compared with Comparative Example 4 (existing technology), the average increase was 32.6%. The fusel oil content of Examples 1-3 was between 0.28-0.35 g / L, significantly lower than that of the comparative examples (0.46-0.63 g / L). Comparative Example 3 had a short fermentation cycle and a high alcohol content (66.2% vol), but its total esters and ethyl acetate were significantly lower, which is consistent with the characteristics of incomplete fermentation.

[0042] Test Example 2 Determination of the content of characteristic flavor components in mung beans Objective: To verify the effect of the brewing method of the present invention on the transformation and retention of characteristic flavor components of mung beans.

[0043] Methods: Base wines prepared in Examples 1-3, Comparative Examples 1 and 4 were used, and headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was employed to detect the characteristic flavor components of mung beans. The main components detected were hexanal, nonanal, and 2-pentylfuran, three typical aroma components of mung beans. Chromatographic conditions: HP-5MS capillary column (30m × 0.25mm × 0.25μm), helium carrier gas (1.0mL / min), temperature program: 40℃ for 3 min, increased to 150℃ at 5℃ / min, then increased to 250℃ at 10℃ / min. Mass spectrometry conditions: EI source, 70 eV, scan range 35-350 amu. External standard method was used for quantification. Each sample was measured in triplicate, and the mean value was taken.

[0044] The results are shown in Table 2.

[0045] Table 2 Comparison of characteristic flavor components in mung beans (μg / L)

[0046] The results showed that the hexanal content in Examples 1-3 ranged from 26.9 to 30.2 μg / L, the nonanal content from 14.2 to 16.1 μg / L, and the 2-pentylfuran content from 11.5 to 13.6 μg / L. Example 3 had the highest hexanal and 2-pentylfuran content, while Example 2 had the highest nonanal content. Compared to Comparative Example 1, the average increases in hexanal, nonanal, and 2-pentylfuran content in Examples 1-3 were 194.6%, 165.5%, and 163.3%, respectively; compared to Comparative Example 4, the average increases were 249.4%, 224.4%, and 242.9%, respectively. This indicates that the present invention can efficiently convert the characteristic flavor components of mung beans, and different process parameters (such as the ratio of red sorghum to mung beans and enzymatic hydrolysis conditions) have a certain influence on the formation of the three flavor components, but overall, it is significantly superior to the prior art.

[0047] Test Example 3 Sensory evaluation experiment Objective: To evaluate the sensory quality of the liquor produced by the brewing method of this invention.

[0048] Methods: A panel of 12 professionals with national baijiu (Chinese liquor) taster qualifications was invited to conduct blind tastings of the base liquors from Examples 1-3 and Comparative Examples 1-4. Evaluation indicators included: color (10 points), aroma (30 points, including 15 points for pure and authentic light aroma and 15 points for prominent mung bean aroma), taste (40 points, including 20 points for sweetness and mellowness), and style (20 points, including 10 points for typicality and 10 points for harmony), for a total score of 100 points. Each sample was randomly numbered, and the average score was taken after independent scoring by the tasters. The tasting environment met the requirements of GB / T 10346-2006 "Rules for the Inspection of Baijiu".

[0049] The results are shown in Table 3.

[0050] Table 3 Sensory evaluation results

[0051] The results showed that the total scores of Examples 1-3 ranged from 90.9 to 91.9, with Example 2 scoring the highest (91.9), followed by Example 1 (91.7), and Example 3 scoring slightly lower (90.9). In the aroma score, the mung bean aroma of Example 2 was more prominent (14.2 points) than that of Example 1 (13.5 points) and Example 3 (13.1 points), possibly related to the higher proportion of mung beans (25 parts) in Example 2. The total scores of Comparative Examples 1-4 ranged from 69.7 to 77.1, showing significant differences from the Example groups.

[0052] Test Example 4 Comparison of alcohol yield and starch utilization rate Objective: To verify the production efficiency of the brewing method of the present invention.

[0053] Methods: Grain was fed according to the processes of Examples 1-3 and Comparative Examples 1-4 (100 kg per batch). The mass (kg) of 65% vol base liquor produced in each batch was recorded, and the alcohol yield was calculated as (base liquor mass / grain mass × 100%). Simultaneously, the total starch content and residual starch content of the raw materials were measured, and the starch utilization rate was calculated using the following formula: Starch utilization rate (%) = (Total starch mass - Residual starch mass) / Total starch mass × 100% Each process was repeated 3 times, and the average value was taken.

[0054] The results are shown in Table 4.

[0055] Table 4 Comparison of alcohol yield and starch utilization rate

[0056] The results showed that the alcohol yield of Examples 1-3 ranged from 45.8% to 46.9%, and the starch utilization rate ranged from 81.9% to 83.1%. Example 3 had the highest alcohol yield (46.9%), followed by Example 1 (46.2%), and Example 2 was slightly lower (45.8%). Compared with Comparative Example 1 (mung beans without pre-saccharification), the alcohol yield of Examples 1-3 increased by an average of 7.1%, and the starch utilization rate increased by an average of 6.6%; compared with Comparative Example 2 (using only koji), the average increases were 16.3% and 15.9%; and compared with Comparative Example 4 (existing technology), the average increases were 12.6% and 12.4%. The alcohol yield of Comparative Example 3 (fermentation cycle of 15 days) (44.6%) was higher than that of Comparative Examples 2 and 4, but lower than that of the Example groups, and its starch utilization rate (78.9%) was still significantly lower than that of the Example groups, indicating that simply shortening the fermentation cycle is not conducive to the full conversion of starch.

[0057] Test Example 5 Process stability experiment Objective: To verify the batch-to-batch stability of the brewing method of the present invention.

[0058] Methods: Five batches of production were carried out continuously according to the process parameters of Example 1 (500 kg of grain per batch). The alcohol content, total ester content, ethyl acetate content, and fusel oil content of the base liquor were measured for each batch, and a sensory evaluation group was organized to conduct a comprehensive evaluation. The relative standard deviation (RSD%) between batches of each indicator was calculated.

[0059] The results are shown in Table 5.

[0060] Table 5. Stability data for 5 consecutive batches of production

[0061] The results showed that in five consecutive batches of production, the inter-batch RSDs for alcohol content, total esters, ethyl acetate, and sensory scores were all less than 2%, while the RSD for fusel oil was 3.85%. Slight fluctuations existed between batches (e.g., the highest ethyl acetate concentration was 1.72 g / L in batch 3, and the lowest was 1.65 g / L in batch 4), which are within the normal range of production fluctuations. This indicates that the brewing method of this invention has good process stability and is suitable for large-scale application.

[0062] Test Example 6 Adaptability experiment of different mung bean varieties Objective: To verify the adaptability of the present invention to different varieties of mung beans.

[0063] Methods: Three common varieties of mung beans—Mung bean, hairy mung bean, and parrot mung bean—were selected and brewed according to the process parameters of Example 1 (100 kg of grain per batch). The total ester content, ethyl acetate content, and characteristic flavor components of mung beans (total hexanal + nonanal + 2-pentylfuran) of the base liquor were determined, and sensory evaluation was performed. Two batches were repeated for each variety, and the average value was taken.

[0064] The results are shown in Table 6.

[0065] Table 6 Comparison of adaptability of different mung bean varieties

[0066] The results showed that all three mung bean varieties could produce baijiu (Chinese liquor) that met quality requirements, but there were some differences. Ming mung bean had the highest total esters, ethyl acetate, total flavor components, and sensory score (91.8 points); Yingge mung bean was second (90.1 points); and Mao mung bean was slightly lower (88.5 points). This indicates that the present invention has good adaptability to different mung bean varieties, with Ming mung bean showing the best overall performance. It can be selected for use based on raw material availability and target flavor.

[0067] Test Example 7 The effect of aging time on the quality of wine Objective: To verify the effect of aging time on improving the quality of the base wine obtained in this invention.

[0068] Methods: New wine (0 months) prepared in Example 1, as well as wine samples aged for 3 months, 6 months, 12 months, and 24 months, were taken. The total ester content and total acid content were determined, and a sensory evaluation group was organized to score them (score criteria were the same as in Test Example 3). Three parallel samples were taken at each time point, and the mean value was taken.

[0069] The results are shown in Table 7.

[0070] Table 7 Changes in wine quality over different aging periods

[0071] The results showed that with prolonged aging, the total ester and total acid content gradually increased, and the sensory score continuously improved. The changes were most significant in the first 6 months, with total ester increasing from 2.45 g / L to 2.86 g / L and the sensory score rising from 83.2 to 91.7. After 6 months, the changes slowed down, with sensory scores at 12 and 24 months being 92.1 and 92.3 respectively, showing little difference. Therefore, the preferred aging time in this invention is no less than 6 months, with 6-12 months being the optimal drinking period.

[0072] The test results above show that the brewing method for red sorghum multi-fermentation of mung bean light-aroma baijiu provided by the present invention is significantly superior to the comparative examples in terms of physicochemical indicators, flavor components, sensory quality, alcohol yield and process stability. The total ester content of Examples 1-3 reached 2.79-2.91 g / L, and the ethyl acetate content reached 1.65-1.71 g / L, which were 32.6% and 36.6% higher than those of Comparative Example 4 (existing technology), respectively. The fusel oil content (0.28-0.35 g / L) was reduced by 44.4%. The total amount of mung bean characteristic flavor components (hexanal, nonanal, 2-pentylfuran) was more than 2.4 times higher than that of Comparative Example 4, with a prominent and natural mung bean aroma. The sensory score reached 90.9-91.9 points, significantly higher than that of the comparative example (69.7-77.1 points). The alcohol yield reached 45.8%-46.9%, and the starch utilization rate reached 81.9%-83.1%, which were 12.6% and 12.4% higher than those of the existing technology, respectively. The batch-to-batch RSD was less than 2% for five consecutive batches of production, indicating good process stability. In summary, this invention achieves efficient transformation and synergistic integration of the characteristic aroma of mung beans while retaining the typical style of light-aroma Daqu Baijiu.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any changes and modifications made to the embodiments described herein based on the innovative concept of the present invention, or equivalent structural or procedural transformations made using the content of the present invention specification, directly or indirectly applying the above technical solutions to other related technical fields, are all included within the scope of protection of the present invention patent.

Claims

1. A brewing method for a light-aroma baijiu made from red sorghum and mung beans through multi-fermentation, characterized in that, Includes the following steps: S1 Raw material preparation and mung bean presaccharification: Take 75-85 parts by weight of red sorghum and 15-25 parts by weight of mung beans. After dehulling the mung beans, perform low-temperature enzymatic hydrolysis and presaccharification treatment to obtain mung bean pretreated product. S2 High-temperature moistening: The red sorghum and mung bean pretreatment materials are mixed and moistened with boiling water at 96℃. The amount of water added is 55-65% of the total mass of the mixture to obtain moistened grain. S3 Steaming and gelatinization: The moistened grain is steamed and gelatinized, and 21-23% of the steamed rice husks are added to obtain cooked grain; S4 Multi-Fermentation Agent Preparation: Using a light-aroma, low-temperature Daqu (a type of starter culture) as the base koji, and compounded with bran koji and enhanced functional microbial koji, a multi-koji fermentation agent is prepared; in the multi-koji fermentation agent, the base koji accounts for 60-70 wt%, the bran koji accounts for 20-25 wt%, and the enhanced functional microbial koji accounts for 5-10 wt%; the total amount of koji used is 19-23% of the grain feed amount. S5 Ground Vat Fermentation: After the cooked grain is spread out to the vat temperature, the multi-koji fermentation agent is added and mixed evenly. The grain is then placed in a ground vat and sealed for fermentation. The fermentation cycle is 28 days, with the peak fermentation temperature controlled at 28-32℃ and the exit temperature at 20-25℃. S6 Distillation: The fermented mash is loaded into a still for distillation, the head and tail are removed, and the middle section of the liquid is collected to obtain the base liquor; S7 Aging: The base liquor is placed in a ceramic jar for aging to obtain a light-aroma baijiu made from red sorghum and multiple yeasts.

2. The brewing method according to claim 1, characterized in that, In step S1, the low-temperature enzymatic hydrolysis and pre-saccharification treatment of mung beans includes: crushing the shelled mung beans to 40-80 mesh, adding 0.1-0.5% of a compound enzyme preparation by weight of the mung beans, and enzymatically hydrolyzing at 50-60°C for 2-6 hours; the compound enzyme preparation contains α-amylase and saccharifying enzyme, with an enzyme activity ratio of 1:1 to 3:

1.

3. The brewing method according to claim 1, characterized in that, In S2, the high-temperature soaking time is 18-24 hours; in S3, the conditions for steaming and gelatinization are: steaming the material for 80 minutes after steaming, the rice husks are pre-steamed for more than 30 minutes, and the rice husks contain rice bran accounting for 30% of their total mass.

4. The brewing method according to claim 1, characterized in that, In step S4, the light-aroma type low-temperature koji is prepared by the following process: 1) Weigh out 55% barley, 35% peas, and 10% mung beans by weight percentage as raw materials for making koji; 2) After mixing the raw materials, crush them and pass them through a 20-mesh sieve. Add water at 38-42% of the total mass of the raw materials and mix evenly. 3) Press the mixture into blocks, place them in a curing room, and cultivate them at 20-25℃. The curing process involves the following stages: mold growth, mold drying, damp fire, high fire, and final fire. The total curing period is 28-32 days. 4) After fermentation, the koji is stored in the warehouse for more than 3 months to obtain the light-aroma type low-temperature koji.

5. The brewing method according to claim 1, characterized in that, In step S4, the enhanced functional starter culture is an ester-producing yeast starter culture, an aroma-producing yeast starter culture, or a mixture of both; in the enhanced functional starter culture, the colony count of the ester-producing yeast is 1×10⁻⁶. 8 ~5×10 8 cfu / g, the colony count of aroma-producing yeast is 2×10⁻⁶. 8 ~1×10 9 cfu / g.

6. The brewing method according to claim 1, characterized in that, In S6, the stilling is loaded with a "two dry and one wet, two small and one large steam" loading mode, and the loading time is 45-55 minutes. "Two dry and one wet" means that a layer of wet mash is laid after every two layers of dry mash, and "two small and one large steam" means that a small steam pressure is used in the early and middle stages of loading, and a large steam pressure is used in the later stage of loading.

7. The brewing method according to claim 1, characterized in that, In S6, the specific operation of extracting the middle section of the liquor is as follows: during the distillation process, observe the flow of the liquor and collect the liquor. When the alcohol content of the liquor drops below 65% vol, stop collecting the middle section of the liquor and collect the tail liquor for re-distillation.

8. The brewing method according to claim 1, characterized in that, In S7, the aging conditions are as follows: the earthenware jars are sealed and aged for more than 6 months in an environment of 15-25℃ and relative humidity of 60-75%, and the wine is stored according to its quality.

9. The brewing method according to claim 1, characterized in that, In step S1, the mass ratio of red sorghum to mung beans is 80:20; in step S4, the total amount of yeast used is 21% of the grain input.

10. A type of light-aroma baijiu made from red sorghum and fermented with multiple yeast starters, characterized in that... The product is prepared by any one of the brewing methods according to claims 1 to 9, and has a total ester content ≥ 2.0 g / L, an ethyl acetate content ≥ 1.2 g / L, and a characteristic mung bean aroma derived from mung bean precursor substances.

Images