Lai liangcaocao rice wine starter and preparation method and application thereof

Abstract

The application discloses a kind of rice wine koji of hot peperweed and its preparation method and application, it is related to microbial fermentation technical field, wherein the preparation method of hot peperweed rice wine koji includes: S1, preparation Chinese herbal medicine extract: hot water extraction is carried out to the mixture of hot peperweed, poria cocos and licorice, filtration is carried out, and extract is obtained;S2, mixing and inoculation: the powder of waxy rice, at least one kind of yeast and at least one kind of lactic acid bacteria is mixed with the extract, kneads into a ball, and then the surface of the koji cake is inoculated with mold;S3, culture: the koji cake after inoculation is placed in sealed or semi-sealed condition and is cultured until mold mycelium grows to preset length;S4, drying: the koji cake after culture is dried to preset moisture content, and the hot peperweed rice wine koji is obtained.The preparation method disclosed in the application solves the problem that the type of microorganism in traditional koji is not clear, unstable and may contain pathogenic bacteria.

Description

Technical Field

[0001] This application relates to the field of microbial fermentation technology, and in particular to a Polygonum hydropiper rice wine starter, its preparation method, and its application. Background Technology

[0002] Qu (fermentation starter) is the backbone of wine, serving as a saccharifying and fermenting agent and aroma enhancer in winemaking. Qu contains the main microorganisms and corresponding enzymes required for fermentation, producing and accumulating various flavor substances during fermentation, playing a crucial role in product quality formation. Xiaogan rice wine's traditional Fengwo qu is a sweet qu, made by grinding and mixing wild bamboo leaves, honeycomb grass, Polygonum hydropiper, Smilax glabra, Verbena officinalis, licorice, cloves, and Ligusticum chuanxiong together, then mixing it with rice flour, kneading it into small balls, and allowing it to ferment naturally in a well-ventilated, dark place. Due to the fluctuating and complex composition of the microbial community in the natural environment, the prepared Fengwo qu has the following drawbacks: (1) the types of microorganisms it contains are difficult to control and unstable; (2) the qu may contain pathogenic bacteria present in the natural environment. Therefore, the existing technology still needs improvement. Summary of the Invention

[0003] The main purpose of this application is to propose a Polygonum hydropiper rice wine starter and its preparation method and application, aiming to solve or at least partially alleviate the problem that the types of microorganisms in existing Polygonum hydropiper rice wine starters are difficult to control and that pathogenic bacteria may exist.

[0004] To achieve the above objectives, in a first aspect, this application proposes a method for preparing Polygonum hydropiper rice wine starter, comprising:

[0005] S1. Preparation of herbal extract: Mix Polygonum hydropiper, Poria cocos and licorice, extract with hot water, filter to obtain extract; S2. Mixing and Inoculation: Mix glutinous rice flour, at least one yeast and at least one lactic acid bacteria powder with the extract, knead into a dough to obtain a koji blank, and then inoculate the surface of the koji blank with mold; S3. Cultivation: Place the inoculated koji blanks under sealed or semi-sealed conditions for cultivation until the mold mycelium grows to the preset length; S4. Drying: Dry the cultured starter to the preset moisture content to obtain the Polygonum hydropiper rice wine starter.

[0006] In one embodiment, the yeast includes Saccharomyces cerevisiae; The lactic acid bacteria include at least one of Lactobacillus plantarum, Lactobacillus fermentum, and Lactococcus lactis. The mold includes Rhizopus oryzae.

[0007] In one embodiment, in step S2, based on the weight of glutinous rice flour, the inoculation amount of mold is 0.5% to 1%, the inoculation amount of yeast is 0.05% to 0.1%, and the inoculation amount of lactic acid bacteria is 0.05% to 0.1%.

[0008] In one embodiment, the yeast and lactic acid bacteria powders are mixed evenly with glutinous rice flour, and then the extract is added. The mold is inoculated onto the surface of the shaped blank using a surface rolling method.

[0009] In one embodiment, the hot water extraction temperature is 70~90°C and the time is 20~40 minutes.

[0010] In one embodiment, the culture temperature is 25~30°C and the time is 24~48 hours.

[0011] In one embodiment, the drying temperature is 40~50°C.

[0012] In one embodiment, the preset moisture content is 12-16%.

[0013] In one embodiment, based on the weight of glutinous rice flour, the amount of Polygonum hydropiper added is 1-5%, the amount of Poria cocos added is 0.5-1%, and the amount of Glycyrrhiza uralensis added is 0.4-0.8%.

[0014] Secondly, this application also proposes a Polygonum hydropiper rice wine starter prepared using the preparation method provided in the first aspect of this application.

[0015] Thirdly, this application also proposes the application of the Polygonum hydropiper rice wine starter prepared by the preparation method provided in the first aspect of this application in the preparation of rice wine.

[0016] The method for preparing Polygonum hydropiper rice wine starter proposed in this application replaces natural inoculation with artificially determined pure microorganisms (molds, yeasts, lactic acid bacteria), and combines them with extracts of traditional Chinese medicine to provide nutrition and flavor. This fundamentally solves the problems of unclear and unstable microbial species and the potential presence of pathogenic bacteria in traditional starter production, and achieves controllability and standardization in starter production.

[0017] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the contents of the specification. Furthermore, in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0019] Figure 1 A flowchart illustrating the preparation method of the Polygonum hydropiper rice wine starter provided in this application.

[0020] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0022] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0023] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0024] Yeast starter, hailed as the "bone of liquor," is an indispensable saccharifying, fermenting, and aroma-generating agent in the brewing process. Its core function lies in its rich content of various microorganisms required for fermentation (such as molds, yeasts, and lactic acid bacteria) and the diverse enzyme systems secreted by these microorganisms (such as amylase, saccharifying enzymes, and proteases). During the brewing process, the microbial community in the yeast starter transforms the starch and protein components in the raw materials into sugars, alcohol, and a series of flavor compounds such as organic acids, esters, and higher alcohols through complex metabolic activities. The composition and proportion of these substances directly determine the aroma, taste, and style of the final product, thus playing a decisive role in the formation of liquor product quality.

[0025] The traditional brewing of rice wine in my country, especially the regionally distinctive Xiaogan rice wine, relies heavily on a unique type of starter called "Fengwo" starter. This traditional starter belongs to the sweet wine starter category, and its production process follows ancient methods with a naturalistic touch. Specifically, it typically selects a variety of plant-based ingredients, including wild bamboo leaves, honeycomb grass, smartweed flowers, smilax glabra, verbena, licorice, cloves, and chuanxiong, which are dried, ground, and mixed into a herbal powder. This herbal powder is then mixed with rice flour (as a base) in a regulated ratio, water is added, and the mixture is kneaded and shaped into small starter cakes. These cakes are then placed in a well-ventilated, dark, and humid indoor environment, where they undergo natural fermentation for several days, relying on naturally occurring microorganisms of uncertain types and quantities. During this process, mycelium gradually grows on the surface of the starter cakes, and an internal microbial community is established. Finally, after drying, the starter becomes the final product.

[0026] However, this traditional preparation method, which relies on inoculation with microorganisms from the natural environment, has several inherent and difficult-to-overcome technical drawbacks: (1) The composition of the microbial community is uncontrollable and extremely unstable: The core quality of yeast lies in the composition of its internal functional microorganisms. Traditional methods rely entirely on microorganisms that randomly attach to the environment, and the microbial population in the environment fluctuates drastically with changes in season, climate, geographical location, and hygiene conditions of the production site. This directly leads to significant differences in the dominant strains and proportions of various microorganisms in yeast produced in different batches, at different times, and in different locations, resulting in extremely large fluctuations in the saccharification power, fermentation power, and aroma-generating ability of the yeast. Therefore, using such yeast for subsequent brewing production makes it difficult to guarantee the consistency of key indicators such as product flavor, taste, and alcohol yield, resulting in poor product quality stability and making standardized production difficult to achieve.

[0027] (2) Safety risks of introducing harmful microorganisms: While the open natural fermentation environment introduces beneficial brewing microorganisms, it is also inevitable that it may be contaminated with unknown bacteria from the air, soil, or the raw materials themselves, including some pathogenic bacteria (such as mycotoxin-producing bacteria, spoilage bacteria, etc.). Once these harmful microorganisms colonize the yeast, they may not only inhibit the growth of beneficial functional bacteria and affect the performance of the yeast, but may also remain in the subsequent brewing process or product, bringing potential food safety hazards and threatening consumer health.

[0028] (3) Production process relies on experience and has poor repeatability: The success of traditional process depends heavily on the personal experience of the koji maker. The control of temperature, humidity and fermentation time is mostly based on sensory judgment. The lack of precise process parameters makes it extremely difficult to replicate the process and scale up production, which restricts the industrialization and large-scale development of traditional specialty rice wine.

[0029] Therefore, in response to the core problems of traditional methods for preparing Polygonum hydropiper rice wine starter, such as uncontrollable microorganisms, product instability, safety risks, and low process standardization, there is an urgent need to invent a novel starter preparation technology that can precisely control the microbial community, ensure product safety and stability, and standardize the process. This application is proposed based on this practical need.

[0030] In a first aspect, embodiments of this application propose a method for preparing rice wine starter artificially inoculated with Polygonum hydropiper, comprising the following steps: S1. Preparation of herbal extract: Mix Polygonum hydropiper, Poria cocos and licorice, extract with hot water, filter to obtain extract; S2. Mixing and Inoculation: Mix glutinous rice flour, at least one yeast strain and at least one lactic acid bacteria powder with the extract, knead into a dough to obtain koji blanks, and then inoculate the surface of the koji blanks with mold. S3. Cultivation: Place the inoculated koji blanks under sealed or semi-sealed conditions for cultivation until the mold mycelium grows to the preset length; S4. Drying: Dry the cultured starter to the preset moisture content to obtain Polygonum hydropiper rice wine starter.

[0031] By replacing natural inoculation with artificially determined pure microbial strains (molds, yeasts, and lactic acid bacteria), and combining this with extracts from traditional Chinese medicine to provide nutrition and flavor, the fundamental problem of unclear, unstable, and potentially pathogenic microbial species in traditional brewing yeast is solved. Regardless of when or where production takes place, as long as the same strain is inoculated, a brewing yeast product with consistent microbial composition, similar enzyme profiles, and clearly defined functions can be obtained. This provides the most fundamental guarantee for the standardization of subsequent Polygonum hydropiper rice wine brewing processes, the uniformity of product quality, and the stable reproduction of flavor, and is a prerequisite for achieving large-scale, industrialized production.

[0032] In some embodiments, the yeast includes Saccharomyces cerevisiae (Saccharomyces cerevisiae). Saccharomyces cerevisiae Saccharomyces cerevisiae, as the main alcohol-producing microorganism, is responsible for converting sugars into alcohol and carbon dioxide, and is the core force driving alcoholic fermentation. At the same time, it produces a wealth of aroma components such as esters and higher alcohols.

[0033] In some embodiments, lactic acid bacteria include Lactobacillus plantarum (Lactobacillus plantarum) Lactobacillus plantarum ), Lactobacillus fermentum ( Lactobacillus fermentum ) and Lactococcus lactis ( Lactococcus lactis At least one of the following. Lactic acid bacteria constitute the acid-producing and flavor-regulating microbiome. Their metabolism produces organic acids such as lactic acid and acetic acid, which can effectively regulate the pH value of the fermentation system, inhibit the growth of miscellaneous bacteria, and improve product stability. At the same time, the interaction between lactic acid bacteria and yeast (such as acid-alcohol esterification) is the key to forming the complex and mellow flavor spectrum of rice wine, especially for reproducing the typical sour aroma and mellow taste of traditional rice wine.

[0034] In some embodiments, the mold includes Rhizopus oryzae ( Rhizopus rice As a major saccharifying microorganism, Rhizopus oryzae secretes amylase and saccharifying enzymes with strong capabilities, which can efficiently convert glutinous rice starch into fermentable sugars, laying the substrate foundation for fermentation and contributing unique flavor precursors.

[0035] The aforementioned yeasts, lactic acid bacteria, and molds were selected based on in-depth analysis of the microbiome of traditional high-quality Fengwo yeast. Even with artificially designed communities replacing the traditional random natural combinations, the core functions of the rice wine yeast are still ensured, achieving a shift from experience to science. During fermentation, these three functional microbial communities form a stable "saccharification-alcohol production-acid production" metabolic network, mutually promoting and restraining each other. This simulates and optimizes the complex microbial interactions in traditional yeast, achieving a synergistic effect of 1+1+1>3, ensuring the efficiency of the fermentation process and the richness and balance of flavor formation. Furthermore, by adding known microorganisms, the risk of introducing unknown microorganisms or pathogens (such as toxin-producing molds and spoilage bacteria) due to natural environmental inoculation, as in traditional methods, is eliminated, ensuring the biosafety of the yeast and subsequent brewed products from the source.

[0036] In some embodiments, in step S2, the inoculation amount of mold is 0.5% to 1% based on the weight of glutinous rice flour. For example, the inoculation amount of mold is 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%. The inoculation amount of yeast is 0.05% to 0.1%. For example, the inoculation amount of yeast is 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, or 0.1%. The inoculation amount of lactic acid bacteria is 0.05% to 0.1%. For example, the inoculation amount of lactic acid bacteria is 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, or 0.1%.

[0037] The high inoculation ratio of Rhizopus oryzae ensures a rapid establishment of saccharification dominance in the early stages of fermentation. Its powerful amylase system quickly and extensively hydrolyzes glutinous rice starch into reducing sugars such as glucose and maltose. This not only provides ample substrate for subsequent yeast fermentation, but more importantly, under the technological objectives of sweet wine starter, rapid sugar production in the early stages and control of the subsequent fermentation depth allow for the retention of a high residual sugar content in the final product. This is the most direct and reliable technical means to achieve the signature "sweet and mellow" taste of Xiaogan rice wine. This ratio range is a threshold determined through repeated experiments: if it is below 0.5%, the saccharification rate is insufficient, which may lead to slow fermentation or insufficient sweetness; if it is above 1%, excessive mycelial growth may affect the physical structure of the starter and produce undesirable flavors.

[0038] The relatively low yeast inoculation ensures stable alcoholic fermentation, preventing the loss of flavor compounds (esters, etc.) or the formation of irritating higher alcohols due to rapid fermentation. The total inoculation of lactic acid bacteria is higher than that of yeast, aiming to create a moderately acidic environment. This mildly acidic environment (established primarily by lactic acid bacteria) effectively inhibits unwanted microorganisms and improves fermentation safety. Simultaneously, yeast produces more flavor esters under slightly acidic pressure; moreover, lactic acid and other organic acids are important components of the rice wine flavor structure, contributing a refreshing sourness that forms a classic "sweet-sour ratio" with the remaining sweetness. This ratio ensures an optimal balance between the yeast's alcohol production capacity and the lactic acid bacteria's acid production capacity, resulting in a full-bodied, harmonious, and non-monotonous flavor.

[0039] In some embodiments, in step S2, the yeast and lactic acid bacteria powders are mixed evenly with glutinous rice flour before the extract is added. The mold is inoculated onto the surface of the koji using a surface rolling method.

[0040] Pre-mixing dried yeast and lactic acid bacteria powders with rice flour ensures a uniform initial distribution of both bacteria within the koji mold. Upon addition of the extract, they initiate revival and growth almost simultaneously at various points within the koji mold. This avoids growth competition and inhibition caused by sequential order or excessively high local concentrations, laying the foundation for a balanced symbiotic relationship between the two within the microenvironment. Simultaneously, they rapidly establish dominance in the anaerobic / micro-aerobic core region not yet occupied by mold, initiating initial acid production and weak fermentation, pre-regulating the internal microenvironment (e.g., lowering pH). This environment, in turn, inhibits the subsequent invasion of other bacteria.

[0041] As an aerobic bacterium, *Rhizopus oryzae* spores germinate rapidly on surfaces rich in moisture and oxygen, with hyphae growing from the surface inwards. Inoculation via surface rolling artificially creates a "spatial gradient" in the microbial community. The mold forms a powerful saccharification "front" in the external oxygen-rich zone, breaking down starch into sugars; some of these sugars diffuse inwards, providing fermentation substrates for the yeast and lactic acid bacteria inside. This outside-in-inside sugar supply and inside-out diffusion of metabolic products (such as acids and alcohols) simulate and optimize a dynamic and efficient micro-ecosystem for material exchange, better reproducing the naturally formed functional stratification in traditional koji molds than random mixed inoculation.

[0042] In some embodiments, in step S1, the hot water extraction temperature is 70~90°C, and the time is 20~40 minutes. For example, the hot water extraction temperature is 70°C, 75°C, 80°C, 85°C, or 90°C, etc., and the time is 20 minutes, 25 minutes, 30 minutes, 35 minutes, or 40 minutes, etc.

[0043] High-temperature hot water extraction can effectively extract the active ingredients of traditional Chinese medicine (such as the antibacterial components of Polygonum hydropiper, and the flavor components of Poria cocos and licorice). At the same time, it can kill the miscellaneous bacteria carried by the herbs in the early stage of the operation, simplify the aseptic operation requirements, and avoid the impact of solid particles of herbs on the appearance of the yeast and the uniform growth of microorganisms.

[0044] In some embodiments, in step S3, the culture temperature is 25~30°C and the culture time is 24~48 hours. For example, the culture temperature can be 25°C, 26°C, 27°C, 28°C, 29°C or 30°C, etc., and the culture time can be 24 hours, 36 hours or 48 hours, etc.

[0045] By setting the culture temperature to 25~30℃, suitable process conditions for microbial growth (especially mycelial production by molds) are provided.

[0046] In some implementations, the preset length in S3 is 3 to 7 mm, for example, the preset length can be 3 mm, 4 mm, 5 mm, 6 mm or 7 mm, etc.

[0047] In some embodiments, the drying temperature in step S4 is 40~50°C. For example, the drying temperature can be 40°C, 45°C, or 50°C.

[0048] The core functional substances in yeast starter, besides the microorganisms themselves, include various extracellular enzymes secreted by them (such as amylase and saccharifying enzymes) and flavor precursors accumulated during cultivation (such as amino acids, peptides, and trace volatile components). These biomolecules and flavor compounds are sensitive to high temperatures. By setting the drying temperature at 40-50℃, which is sufficient to drive rapid evaporation of moisture, shortening the drying time, and reducing the risk of potential microbial contamination or adverse fermentation, while remaining well below the threshold that causes most enzymes to rapidly denature and become inactive (which typically begins to occur significantly above 60℃) and trigger drastic flavor changes such as the Maillard reaction, the enzyme activity and flavor potential of the dried yeast starter are preserved to the greatest extent.

[0049] In some implementations, the preset moisture content is 12% to 16%. For example, the preset moisture content is 12%, 13%, 14%, 15%, or 16%, etc.

[0050] By controlling the preset moisture content at 12%~16%, the growth and metabolic activities of microorganisms in the Polygonum hydropiper rice wine starter can be effectively inhibited, avoiding changes in composition, heat production, or self-consumption caused by slow growth during storage. Simultaneously, the integrity of the microbial cell membrane and key protein structure is maintained, maximizing the viability of the microorganisms. When the starter is rehydrated during subsequent brewing, the cells can recover more quickly and restore metabolic activity, ensuring a rapid start to fermentation.

[0051] In some embodiments, based on the weight of glutinous rice flour, the amount of Polygonum hydropiper added is 1-5%, the amount of Poria cocos added is 0.5-1%, and the amount of licorice added is 0.4-0.8%. For example, based on the weight of glutinous rice flour, the amount of Polygonum hydropiper added is 1%, 2%, 3%, 4%, or 5%, etc.; the amount of Poria cocos added is 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%, etc.; and the amount of licorice added is 0.4%, 0.5%, 0.6%, 0.7%, or 0.8%, etc.

[0052] This application also provides a Polygonum hydropiper rice wine starter prepared using the preparation method described above.

[0053] This application also provides an application of the Polygonum hydropiper rice wine starter prepared by the preparation method described above in the preparation of rice wine.

[0054] The following specific examples provide further details.

[0055] Example 1 bacterial strains: Mold: Angel sweet wine yeast, Rhizopus oryzae, Rhizopus rice The inoculation amount is 0.6% (based on the weight of glutinous rice flour, the same below).

[0056] Yeast: Angel high-activity dry yeast, brewer's yeast. Saccharomyces cerevisiae The vaccination rate was 0.06%. Lactic acid bacteria: Lactobacillus plantarum, Lactobacillus plantarum Food grade, inoculation amount 0.06%; Lactobacillus fermentum, Lactobacillus fermentum Food grade, inoculation amount 0.06%; Lactococcus lactis, Lactococcus lactis Food grade, inoculation amount 0.06%.

[0057] (1) Weigh out 3 g of Polygonum hydropiper, 1 g of Poria cocos, and 0.6 g of Glycyrrhiza uralensis according to the formula, and place them in an Erlenmeyer flask. Add 120 mL of distilled water, extract in an 80°C water bath for 30 minutes, and filter to obtain the extract.

[0058] (2) Weigh 100g of glutinous rice flour, and weigh yeast powder and three types of freeze-dried lactic acid bacteria powder according to the inoculation amount requirements. Mix the glutinous rice flour, yeast powder and freeze-dried lactic acid bacteria powder evenly, add the extract, stir and knead into a dough. Weigh the mold powder according to the inoculation amount requirements, sprinkle it evenly on the surface of the yeast, and let the yeast roll to complete the mold inoculation. Place the kneaded yeast precursor into a culture container and seal it with plastic wrap.

[0059] (3) Place the culture container in the incubator and incubate at 28℃ for 24~36h. Observe the growth of mold hyphae. When the hyphae are about 5 mm long and the hyphae on the surface are evenly distributed, the culture can be stopped.

[0060] (4) Remove the plastic wrap, dry in a hot air drying oven at 45°C until the surface hardens and then break it. Continue drying until about 100g (the same weight as glutinous rice flour, at which point the moisture content is about 14%), grind it into powder, and store it in a sealed container at room temperature.

[0061] Example 2 This embodiment uses the same strains as in Example 1, wherein the inoculation amount of mold is 0.5%, yeast is 0.05%, Lactobacillus plantarum is 0.05%, Lactobacillus fermentum is 0.05%, and Lactococcus lactis is 0.05%.

[0062] (1) Weigh out 1 g of Polygonum hydropiper, 1 g of Poria cocos, and 0.8 g of Glycyrrhiza uralensis according to the formula, and place them in an Erlenmeyer flask. Add 120 mL of distilled water, extract in a 90°C water bath for 20 minutes, and filter to obtain the extract.

[0063] (2) Weigh 100g of glutinous rice flour, and weigh yeast powder and three types of freeze-dried lactic acid bacteria powder according to the inoculation amount requirements. Mix the glutinous rice flour, yeast powder and freeze-dried lactic acid bacteria powder evenly, add the extract, stir and knead into a dough. Weigh the mold powder according to the inoculation amount requirements, sprinkle it evenly on the surface of the yeast, and let the yeast roll to complete the mold inoculation. Place the kneaded yeast precursor into a culture container and seal it with plastic wrap.

[0064] (3) Place the culture container in the incubator and incubate at 25°C for 24-36 hours. Observe the growth of mold hyphae. When the hyphae are about 3 mm long and the hyphae are evenly distributed on the surface, the culture can be stopped.

[0065] (4) Remove the plastic wrap, dry in a hot air drying oven at 40°C. Once the surface hardens, break it. Continue drying until the moisture content is about 12%. Grind it into powder and store it in a sealed container at room temperature.

[0066] Example 3 This embodiment uses the same strains as in Example 1, wherein the inoculation amount of mold is 1%, yeast is 0.1%, Lactobacillus plantarum is 0.1%, Lactobacillus fermentum is 0.1%, and Lactococcus lactis is 0.1%.

[0067] (1) Weigh out 5 g of Polygonum hydropiper, 0.5 g of Poria cocos, and 0.4 g of Glycyrrhiza uralensis according to the formula, and place them in an Erlenmeyer flask. Add 120 mL of distilled water, extract in an 80℃ water bath for 40 minutes, and filter to obtain the extract.

[0068] (2) Weigh 100g of glutinous rice flour, and weigh yeast powder and three types of freeze-dried lactic acid bacteria powder according to the inoculation amount requirements. Mix the glutinous rice flour, yeast powder and freeze-dried lactic acid bacteria powder evenly, add the extract, stir and knead into a dough. Weigh the mold powder according to the inoculation amount requirements, sprinkle it evenly on the surface of the yeast, and let the yeast roll to complete the mold inoculation. Place the kneaded yeast precursor into a culture container and seal it with plastic wrap.

[0069] (3) Place the culture container in the incubator and incubate at 30℃ for 24~36h. Observe the growth of mold hyphae. When the hyphae are about 7 mm long and the hyphae are evenly distributed on the surface, the culture can be stopped.

[0070] (4) Remove the plastic wrap, dry in a hot air drying oven at 50°C. Once the surface hardens, break it up. Continue drying until the moisture content is about 16%, grind it into powder, and store it in a sealed container at room temperature.

[0071] Comparative Example 1 This comparative example uses the same preparation method as Example 1, except that in (2), 100g of glutinous rice flour is weighed, and yeast powder, three types of freeze-dried lactic acid bacteria powder, and mold powder are weighed according to the inoculation amount requirements. The glutinous rice flour, yeast powder, three types of freeze-dried lactic acid bacteria powder, and mold powder are mixed evenly, the extract is added, stirred, and kneaded into a dough. The kneaded yeast precursor is placed in a culture container and sealed with plastic wrap.

[0072] Comparative Example 2 This comparative example uses the same preparation method as Example 1, except that the inoculation amount of mold is 2%, yeast is 0.06%, Lactobacillus plantarum is 0.06%, Lactobacillus fermentum is 0.06%, and Lactococcus lactis is 0.06%.

[0073] Comparative Example 3 This comparative example uses the same preparation method as Example 1, except that the mold inoculation amount is 1%, the yeast inoculation amount is 0.06%, and no lactic acid bacteria are inoculated.

[0074] The growth status of the rice wine koji molds prepared in Examples 1-3 and Comparative Examples 1-3 was analyzed by saccharification power testing. The amylase produced by the mold hydrolyzes the starch in rice into glucose. The saccharification power can be represented by measuring the amount of glucose produced per unit time and per unit mass of koji. The specific steps are as follows: (1) Reagent preparation: soluble starch solution, acetic acid-sodium acetate buffer, DNS (3,5-dinitrosalicylic acid) reagent.

[0075] (2) Determination: The yeast prepared in quantitative examples 1-3 and comparative examples 1-3 were reacted with starch solution at 35°C for 30 minutes. After color development by DNS method, the absorbance was measured at a wavelength of 540 nm. The amount of glucose produced was calculated by referring to the glucose standard curve. The test results are shown in Table 1.

[0076] Table 1. Saccharification power test

[0077] As can be seen from Table 1, the yeast prepared in Examples 1, 2 and 3 all have high saccharification power. Changing the inoculation method and the amount of inoculation will reduce the saccharification power.

[0078] The rice wine starters prepared in Examples 1-3 and Comparative Examples 1-3 were used to brew rice wine using the same method, and the taste of the final brewed rice wine was rated.

[0079] The method for brewing rice wine is as follows: (1) Cleaning: Select whole, mold-free glutinous rice grains, weigh 70g for each portion, and rinse 3 times with pure water.

[0080] (2) Soaking: After washing, soak in enough pure water for 24 hours until it can be crushed by hand.

[0081] (3) Steaming: After soaking, put the glutinous rice into a steamer and heat it with an 1800 W induction cooker for 50 minutes. Cook until the rice grains are loose, transparent and without white core.

[0082] (4) Cooling: Pour 100 mL of cooled boiled water over the rice to cool it down to 25-30℃.

[0083] (5) Mixing with yeast: Add a certain amount of yeast to each portion of cooked glutinous rice and mix well.

[0084] (6) Building a nest: After gathering and compacting the rice grains with chopsticks, poke a hole in the middle to observe the wine production.

[0085] (7) Fermentation: Place in a constant temperature incubator and ferment at 28℃ for 48 hours.

[0086] The specific steps for rating the flavor of brewed rice wine include: (1) Preparation for evaluation Tasting panel: Organize 5-10 healthy individuals who do not smoke or drink excessively and are sensitive to taste. Avoid consuming spicy or irritating foods before tasting.

[0087] Sample: Take about 15-20 mL of rice wine sample into a clean and transparent tasting glass and perform blind coded testing.

[0088] Environment: Quiet, odorless, and well-lit.

[0089] (2) Scoring criteria The quality of rice wine is scored using a 100-point system, which is divided into four dimensions: appearance, aroma, taste, and style. The specific scoring rules are shown in Table 2.

[0090] Table 2. Scoring Criteria

[0091] (3) According to the scoring criteria, the rice wine brewed using the rice wine yeast prepared in Examples 1-3 and Comparative Examples 1-3 was scored, and the results are shown in Table 3.

[0092] Table 3. Rice Wine Scoring Table

[0093] As can be seen from Table 3, the rice wine brewed with the yeast prepared in Examples 1, 2 and 3 has a higher sensory evaluation score. Changing the inoculation method, inoculation amount and strain combination will affect the fermentation process and lead to a deterioration in the quality of rice wine.

[0094] The above description is merely an exemplary embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the technical concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A method for preparing Polygonum hydropiper rice wine starter, characterized in that, include: S1. Preparation of herbal extract: Mix Polygonum hydropiper, Poria cocos and licorice, extract with hot water, filter to obtain extract; S2. Mixing and Inoculation: Mix glutinous rice flour, at least one yeast and at least one lactic acid bacteria powder with the extract, knead into a dough to obtain a koji blank, and then inoculate the surface of the koji blank with mold; S3. Cultivation: Place the inoculated koji blanks under sealed or semi-sealed conditions for cultivation until the mold mycelium grows to the preset length; S4. Drying: Dry the cultured starter to the preset moisture content to obtain the Polygonum hydropiper rice wine starter.

2. The method for preparing Polygonum hydropiper rice wine starter as described in claim 1, characterized in that, The yeast includes Saccharomyces cerevisiae; The lactic acid bacteria include at least one of Lactobacillus plantarum, Lactobacillus fermentum, and Lactococcus lactis. The mold includes Rhizopus oryzae.

3. The method for preparing Polygonum hydropiper rice wine starter as described in claim 1, characterized in that, In step S2, based on the weight of glutinous rice flour, the inoculation amount of mold is 0.5%~1%, the inoculation amount of yeast is 0.05%~0.1%, and the inoculation amount of lactic acid bacteria is 0.05%~0.1%.

4. The method for preparing Polygonum hydropiper rice wine starter as described in claim 1, characterized in that, After the yeast and lactic acid bacteria powders are mixed evenly with glutinous rice flour, the extract is added. The mold is inoculated onto the surface of the shaped blank using a surface rolling method.

5. The method for preparing Polygonum hydropiper rice wine starter as described in claim 1, characterized in that, The hot water extraction temperature is 70~90℃, and the time is 20~40 minutes.

6. The method for preparing Polygonum hydropiper rice wine starter as described in claim 1, characterized in that, The culture temperature is 25~30℃, and the time is 24~48 hours.

7. The method for preparing Polygonum hydropiper rice wine starter as described in claim 1, characterized in that, The drying temperature is 40~50℃; The preset moisture content is 12-16%.

8. The method for preparing Polygonum hydropiper rice wine starter as described in claim 1, characterized in that, Based on the weight of glutinous rice flour, the amount of Polygonum hydropiper added is 1-5%, the amount of Poria cocos added is 0.5-1%, and the amount of Glycyrrhiza uralensis added is 0.4-0.8%.

9. A Polygonum hydropiper rice wine starter prepared by the preparation method according to any one of claims 1 to 8.

10. The application of a Polygonum hydropiper rice wine starter prepared by any one of the preparation methods described in claims 1 to 8 in the preparation of rice wine.

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