A distiller's yeast for rice wine production and a preparation method thereof

Abstract

The invention discloses a distiller's yeast for rice wine production and a preparation method thereof. The preparation method pre-treats DM-301 macroporous adsorption resin and SiO2 aerogel with anhydrous ethanol and β-phenylethanol solution, then adds flour, water, edible yeast and acetic acid for the first fermentation, adds flour and lactic acid for the second fermentation to make filling material, and finally rice flour, filling material, mother koji and water are made into koji balls in a certain proportion, and the koji is dried in the air. The preparation method of the distiller's yeast of the present invention is similar to the step of making bread. The prepared distiller's yeast can not only suppress the pollution of some pathogens and miscellaneous bacteria, but also make full use of the loose and porous characteristics of the filling material to promote the growth of yeast and rhizopus, improve the survival ability of beneficial bacteria, and then shorten the fermentation time, improve the fermentation efficiency of rice wine, and improve the quality of the brewed rice wine and yellow wine.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, in particular to a distiller's yeast for producing rice wine and a preparation method thereof. Background Art

[0002] Yeast (or koji) is a saccharifying and fermenting agent made from various grains or their by-products, cultivated under suitable environmental conditions. It contains a rich array of microorganisms and related enzymes capable of saccharification, fermentation, and aroma production. The ancient Chinese treatise "The Exploitation of the Works of Nature" contains relevant records of koji, specifically emphasizing its crucial role in winemaking. Today, while inheriting traditional koji-making techniques, koji production is progressing towards mechanization and standardization, and research on koji has also become diverse and innovative. The production processes for koji in my country are diverse, with complex and overlapping classifications. While the microbial colony structures in different kojis vary, the functions of these microorganisms are largely the same: molds, bacteria, and yeasts contribute to saccharification, aroma production, and wine production, respectively. During fermentation, the microorganisms produce a large number of enzymes. These enzymes and microorganisms combine with the koji raw material to form a crude enzyme preparation with strong saccharification, protein degradation, and ester production capabilities. Different types of koji are used to produce different types of alcohol.

[0003] The production method for rice wine koji has traditionally been natural fermentation, with a certain amount of Chinese herbal medicine added during the production process to prevent contamination by foreign bacteria and to loosen the mash. Chinese patents CN105331484A: A Rice Wine Koji and Its Production Method, CN101974385A: A Rice Wine Koji and Its Preparation Method, and CN101974385A: A Rice Wine Koji and Its Preparation Method have disclosed methods for making rice wine koji. All of these utilize various plants, such as Polygonum hydropiper. While this can prevent contamination to a certain extent, it also inhibits the growth and metabolism of key microorganisms in the koji, such as Rhizopus and yeast, and does not comply with the requirements of the Food Safety Law (Article 34, Paragraph 1: It is prohibited to produce food using non-food raw materials or to add chemical substances other than food additives or other substances that may be harmful to human health). Koji microorganisms are the primary driver of fermentation and wine production. Koji production in my country is hampered by a low proportion of high-quality koji, a low level of mechanization, and difficulty controlling koji insects. Therefore, the present application proposes a distiller's yeast for rice wine production without adding Polygonum hydropiper and a preparation method thereof, in order to obtain high-quality distiller's yeast. Summary of the Invention

[0004] In view of the above-mentioned defects of the prior art, the present invention proposes a distiller's yeast for rice wine production and a preparation method thereof to solve the problems raised by the above-mentioned background technology.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A method for preparing distiller's yeast for rice wine production comprises the following steps:

[0007] (1) Pretreatment of adsorption and filling materials

[0008] First, the DM-301 macroporous adsorption resin is soaked in anhydrous ethanol for 4 to 5 hours, and then washed with pure water until there is no ethanol smell. Then, the DM-301 macroporous adsorption resin and the SiO2 aerogel are respectively placed in a β-phenylethanol solution with a mass concentration of 0.11 to 2.5% and immersed for 20 to 24 hours. After the immersion is completed, the resin is dried at a temperature of 50 to 70° C. and a drying time of 1 to 2 hours to obtain the pretreated DM-301 macroporous adsorption resin and SiO2 aerogel.

[0009] (2) Preparation of filling materials

[0010] The pretreated DM-301 macroporous adsorption resin and SiO2 aerogel obtained in step (1) are crushed respectively, and the DM-301 macroporous adsorption resin and SiO2 aerogel are mixed in a mass ratio of 3-12:5-15 to obtain a pretreated mixed material; flour, water, edible yeast and acetic acid accounting for 80% of the mass of the pretreated mixed material are added to the pretreated mixed material, and the mixture is kneaded and evenly mixed into a dough, and a first fermentation is carried out at a temperature of 26-28°C for 50-60 minutes; after the first fermentation is completed, the dough is kneaded for 15-20 minutes to expel gas in the dough; flour and lactic acid accounting for 20% of the mass of the pretreated mixed material are then added and kneaded evenly, and a second fermentation is carried out at a temperature of 35-40°C for 40-50 minutes, and after the second fermentation is completed, the dough is first baked at a temperature of 170-200°C for 30-50 minutes, and then the baked dough is placed in a temperature of 100-120°C for drying for 1.5-2 hours, and the dried dough is crushed and passed through a 20-mesh sieve to obtain a filling material;

[0011] (3) Preparation of koji

[0012] The rice is ground, passed through a 40-mesh sieve, and sterilized in an oven at 110°C for 30 minutes to obtain rice flour. The rice flour, filler material, mother koji, and water are mixed in a weight ratio of 8-20:1-3:0.35-0.80:20-50, stirred evenly, and formed into koji balls with a diameter of 2-5 cm. The balls are then incubated at a temperature of 25-35°C for 2-5 days, with the koji turned every 8-15 hours. After the balls are evenly covered with mycelium, the koji is ventilated and air-dried until the moisture in the balls evaporates to less than 12%, thereby obtaining the finished wine koji. The strains in the mother koji include Rhizopus and yeast.

[0013] Preferably, DM-301 macroporous adsorption resin is purchased from Shanghai Mosu Scientific Instrument Co., Ltd.; SiO2 aerogel is purchased from Zhongshan Lande Environmental Protection and Energy Saving Engineering Co., Ltd., with a pore size of 50-100 nm and a porosity of >90%.

[0014] Preferably, edible yeast is purchased from Angel Yeast Co., Ltd.; acetic acid is purchased from Zhengzhou Lingde Chemical Products Co., Ltd., CAS No.: 64-19-7, density: 1.0492; lactic acid is purchased from Guangzhou Tianjia Biotechnology Co., Ltd., CAS No.: 50-21-5.

[0015] Preferably, the mother koji is the old koji used as an initiator for fermentation of the new koji when making the new koji. It is a high-quality koji obtained by the technicians of Hubei Mipo Biotechnology Co., Ltd. from the initial koji after domestication.

[0016] Preferably, the mass concentration of the β-phenylethanol solution is 1.0-1.2%.

[0017] Preferably, the mass concentration of the β-phenylethanol solution in step (1) is 1.1%, and during the impregnation, the volume ratio of DM-301 macroporous adsorption resin, SiO2 aerogel and β-phenylethanol solution is 1-3:1-3:10-20.

[0018] Preferably, in step (2), the DM-301 macroporous adsorption resin and the SiO2 aerogel are mixed in a mass ratio of 3 to 7:5 to 10.

[0019] Preferably, in step (2), the DM-301 macroporous adsorption resin and the SiO2 aerogel are mixed in a mass ratio of 4:6.

[0020] Preferably, in step (2), the amount of water added during the first fermentation is 60-70% of the weight of the total flour, the amount of edible yeast added is 0.5-1.0% of the weight of the total flour, the amount of acetic acid added is 0.1-0.3% of the amount of flour used in the first fermentation, and the amount of lactic acid added is 0.3-0.6% of the amount of flour used in the second fermentation.

[0021] Preferably, the amounts of Rhizopus and yeast in the mother koji of step (3) are 0.002-0.30% and 0.001-0.040% of the weight of the mother koji, respectively.

[0022] Fungi such as Rhizopus can convert starch into soluble sugars for use by other microorganisms, producing small amounts of organic acids during the saccharification process. The proteases metabolized by Aspergillus hydrolyze proteins into prions, peptones, and polypeptides, ultimately forming amino acids. Amino acids are precursors to the aroma of wine and contribute to its richness.

[0023] The primary functions of yeast are alcoholization and esterification. Yeast metabolism produces alcohol. The esterification abilities of Candida and Hansenula give wine its rich, fragrant esters. Furthermore, glycerol and other polyols produced by yeast metabolism are also crucial for the quality and flavor of a wine.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) β-phenylethanol is an important flavoring substance in rice wine and yellow wine. It has an elegant aroma of honey and roses, and leaves a sweet and refreshing taste. In addition, β-phenylethanol can inhibit bacteria, especially Gram-negative bacteria, such as many pathogenic bacteria such as Escherichia coli and Pseudomonas aeruginosa. The present invention utilizes the specific antibacterial function of β-phenylethanol. The macroporous adsorption resin and SiO2 aerogel are impregnated with a food-grade β-phenylethanol solution and then dried. The β-phenylethanol can be fixed in the filling material, thereby inhibiting the contamination of some pathogenic bacteria and miscellaneous bacteria during the preparation of the koji, but does not inhibit the growth of fungi such as Rhizopus and yeast.

[0026] (2) Taking advantage of the loose and porous nature of the filling material and referring to the practice of baking bread, the outer surface of the filling material is the holes produced by the secondary fermentation of yeast (acetic acid and lactic acid are added in the second fermentation, making the dough weakly acidic, more thorough yeast fermentation, and looser dough). The inner part is the porous structure of macroporous adsorption resin and SiO2 aerogel itself. Adding it to the koji embryo has a better loosening effect than using other materials such as whole macroporous resin and traditional water chestnut. From the inside to the outer surface of the koji embryo, there are holes of different types and sizes, which are very conducive to the growth of dominant microorganisms in the koji.

[0027] (3) The appropriate ratio of macroporous adsorption resin and SiO2 aerogel is beneficial to the fermentation and quality of koji. If the filling material is too dense, it is difficult to achieve a loose effect, and the water inside the koji mash is difficult to drain, which can easily cause water accumulation, leading to sourness of the koji mash and slow growth of microorganisms. If it is too loose, the koji blank will have low viscosity, the surface of the koji blank will be rough and easy to crack, leading to the infiltration of miscellaneous bacteria, and the heat of the koji mash will dissipate quickly, affecting the growth and reproduction of beneficial microorganisms. DETAILED DESCRIPTION

[0028] The technical solution of the present invention will be further described in detail below in conjunction with specific implementation methods.

[0029] Example 1

[0030] 1. A method for preparing distiller's yeast for rice wine production, comprising the following steps:

[0031] (1) Pretreatment of adsorption and filling materials

[0032] First, the DM-301 macroporous adsorption resin was soaked in anhydrous ethanol for 4 hours and washed with pure water until there was no ethanol smell. Then, the DM-301 macroporous adsorption resin and SiO2 aerogel were immersed in a β-phenylethanol solution with a mass concentration of 1.0% for 20 hours. After the impregnation, the resin was dried at a temperature of 50°C for 1 hour to obtain the pretreated DM-301 macroporous adsorption resin and SiO2 aerogel.

[0033] (2) Preparation of filling materials

[0034] The pretreated DM-301 macroporous adsorption resin and SiO2 aerogel obtained in step (1) are crushed respectively, and the DM-301 macroporous adsorption resin and SiO2 aerogel are mixed in a mass ratio of 3:5 to obtain a pretreated mixed material; flour, water, edible yeast and acetic acid accounting for 80% of the mass of the pretreated mixed material are added to the pretreated mixed material, and the mixture is kneaded evenly into a dough, and the dough is fermented for the first time at a temperature of 26°C for 50 minutes; after the first fermentation is completed, the dough is kneaded for 15 minutes to expel the gas in the dough; flour accounting for 20% of the mass of the pretreated mixed material and lactic acid accounting for 0.3% of the amount of flour used for the second fermentation are added and kneaded evenly, and the dough is fermented for the second time at a temperature of 35°C for 40 minutes. After the second fermentation is completed, the dough is baked at a temperature of 170°C for 30 minutes, and then the baked dough is dried at a temperature of 100°C for 1.5 hours. The dried dough is crushed and passed through a 20-mesh sieve to obtain a filling material;

[0035] (3) Preparation of koji

[0036] The rice is ground, passed through a 40-mesh sieve, and sterilized in an oven at 110°C for 30 minutes to obtain rice flour. The rice flour, filler material, mother koji, and water are mixed in a weight ratio of 8:1:0.35:20 and stirred evenly to form koji balls with a diameter of 2 cm. The balls are then incubated at 25°C for 2 days, turning the koji every 8 hours. Once the balls are evenly covered with mycelium, the koji is ventilated and air-dried until the moisture content in the balls is reduced to less than 12%, thereby obtaining the finished koji. The mother koji contains fungi including Rhizopus and yeast.

[0037] During the impregnation in step (1), the volume ratio of DM-301 macroporous adsorption resin, SiO2 aerogel and β-phenylethanol solution is 1:1:10.

[0038] In the step (2), the amount of water added during the first fermentation is 60% of the weight of the total flour, the amount of edible yeast added is 0.5% of the weight of the total flour, and the amount of acetic acid added is 0.1% of the amount of flour used for the first fermentation.

[0039] The amounts of Rhizopus and yeast in the mother koji of step (3) are 0.002% and 0.001% of the weight of the mother koji respectively.

[0040] Example 2

[0041] A method for preparing distiller's yeast for rice wine production comprises the following steps:

[0042] (1) Pretreatment of adsorption and filling materials

[0043] First, the DM-301 macroporous adsorption resin was soaked in anhydrous ethanol for 5 hours and washed with pure water until there was no ethanol smell. Then, the DM-301 macroporous adsorption resin and SiO2 aerogel were immersed in a β-phenylethanol solution with a mass concentration of 1.2% for 24 hours. After the impregnation, the resin was dried at 70°C for 2 hours to obtain the pretreated DM-301 macroporous adsorption resin and SiO2 aerogel.

[0044] (2) Preparation of filling materials

[0045] The pretreated DM-301 macroporous adsorption resin and SiO2 aerogel obtained in step (1) are crushed respectively, and the DM-301 macroporous adsorption resin and SiO2 aerogel are mixed at a mass ratio of 7:10 to obtain a pretreated mixed material; flour, water, edible yeast and acetic acid accounting for 80% of the mass of the pretreated mixed material are added to the pretreated mixed material, and the mixture is kneaded evenly into a dough, and the dough is fermented for the first time at a temperature of 28°C for 60 minutes; after the first fermentation is completed, the dough is kneaded for 20 minutes to expel gas in the dough; flour accounting for 20% of the mass of the pretreated mixed material and lactic acid accounting for 0.6% of the amount of flour used for the second fermentation are added and kneaded evenly, and the dough is fermented for the second time at a temperature of 40°C for 50 minutes. After the second fermentation is completed, the dough is baked at a temperature of 200°C for 50 minutes, and then the baked dough is dried at a temperature of 120°C for 2 hours. The dried dough is crushed and passed through a 20-mesh sieve to obtain a filling material;

[0046] (3) Preparation of koji

[0047] The rice is ground, passed through a 40-mesh sieve, and sterilized in an oven at 110°C for 30 minutes to obtain rice flour. The rice flour, filler material, mother koji, and water are mixed in a weight ratio of 20:3:0.80:50 and stirred evenly to form koji balls with a diameter of 5 cm. The balls are then incubated at 35°C for 5 days, turning the koji every 15 hours. Once the balls are evenly covered with mycelium, the koji is ventilated and air-dried until the moisture content in the balls is reduced to less than 12%, thereby obtaining the finished koji. The mother koji contains fungi including Rhizopus and yeast.

[0048] In step (1), during the impregnation, the volume ratio of DM-301 macroporous adsorption resin, SiO2 aerogel and β-phenylethanol solution is 3:3:20.

[0049] In the step (2), the amount of water added during the first fermentation is 70% of the weight of the total flour, the amount of edible yeast added is 1.0% of the weight of the total flour, and the amount of acetic acid added is 0.3% of the amount of flour used for the first fermentation.

[0050] The amounts of Rhizopus and yeast in the mother koji of step (3) are 0.30% and 0.040% of the weight of the mother koji respectively.

[0051] Example 3

[0052] A method for preparing distiller's yeast for rice wine production comprises the following steps:

[0053] (1) Pretreatment of adsorption and filling materials

[0054] First, the DM-301 macroporous adsorption resin was soaked in anhydrous ethanol for 4.5 hours and washed with pure water until there was no ethanol smell. Then, the DM-301 macroporous adsorption resin and SiO2 aerogel were immersed in a β-phenylethanol solution with a mass concentration of 1.1% for 22 hours. After the impregnation, the resin was dried at 60°C for 1.5 hours to obtain the pretreated DM-301 macroporous adsorption resin and SiO2 aerogel.

[0055] (2) Preparation of filling materials

[0056] The pretreated DM-301 macroporous adsorption resin and SiO2 aerogel obtained in step (1) are crushed respectively, and the DM-301 macroporous adsorption resin and SiO2 aerogel are mixed at a mass ratio of 4:6 to obtain a pretreated mixed material; flour, water, edible yeast and acetic acid accounting for 80% of the mass of the pretreated mixed material are added to the pretreated mixed material, and the mixture is kneaded evenly into a dough, and the dough is fermented for the first time at a temperature of 27°C for 55 minutes; after the first fermentation is completed, the dough is kneaded for 18 minutes to expel the gas in the dough; flour accounting for 20% of the mass of the pretreated mixed material and lactic acid accounting for 0.5% of the amount of flour used for the second fermentation are added and kneaded evenly, and the dough is fermented for the second time at a temperature of 38°C for 45 minutes. After the second fermentation is completed, the dough is baked at a temperature of 180°C for 45 minutes, and then the baked dough is dried at a temperature of 110°C for 1.8 hours. The dried dough is crushed and passed through a 20-mesh sieve to obtain a filling material;

[0057] (3) Preparation of koji

[0058] The rice is ground, passed through a 40-mesh sieve, and sterilized in an oven at 110°C for 30 minutes to obtain rice flour. The rice flour, filler material, mother koji, and water are mixed in a weight ratio of 12:2:0.70:40, stirred evenly, and formed into koji balls with a diameter of 3 cm. The balls are then incubated at 30°C for 3 days, with the koji turned every 10 hours. Once the balls are evenly covered with mycelium, the koji is ventilated and air-dried until the moisture content in the balls is reduced to less than 12%, thereby obtaining the finished koji. The mother koji contains fungi including Rhizopus and yeast.

[0059] In step (1), during the impregnation, the volume ratio of DM-301 macroporous adsorption resin, SiO2 aerogel and β-phenylethanol solution is 2:2:15.

[0060] In the step (2), the amount of water added during the first fermentation is 65% of the weight of the total flour, the amount of edible yeast added is 0.7% of the weight of the total flour, and the amount of acetic acid added is 0.2% of the amount of flour used for the first fermentation.

[0061] The amounts of Rhizopus and yeast in the mother koji of step (3) are 0.20% and 0.030% of the weight of the mother koji respectively.

[0062] Example 4

[0063] The difference from Example 3 is that the mass concentration of the β-phenylethanol solution is changed to 0.11%, and the other steps and components remain unchanged.

[0064] A method for preparing distiller's yeast for rice wine production comprises the following steps:

[0065] (1) Pretreatment of adsorption and filling materials

[0066] First, the DM-301 macroporous adsorption resin was soaked in anhydrous ethanol for 4.5 hours and washed with pure water until there was no ethanol smell. Then, the DM-301 macroporous adsorption resin and SiO2 aerogel were immersed in a β-phenylethanol solution with a mass concentration of 0.11% for 22 hours. After the impregnation, the resin was dried at 60°C for 1.5 hours to obtain the pretreated DM-301 macroporous adsorption resin and SiO2 aerogel.

[0067] (2) Preparation of filling materials

[0068] The pretreated DM-301 macroporous adsorption resin and SiO2 aerogel obtained in step (1) are crushed respectively, and the DM-301 macroporous adsorption resin and SiO2 aerogel are mixed at a mass ratio of 4:6 to obtain a pretreated mixed material; flour, water, edible yeast and acetic acid accounting for 80% of the mass of the pretreated mixed material are added to the pretreated mixed material, and the mixture is kneaded evenly into a dough, and the dough is fermented for the first time at a temperature of 27°C for 55 minutes; after the first fermentation is completed, the dough is kneaded for 18 minutes to expel the gas in the dough; flour accounting for 20% of the mass of the pretreated mixed material and lactic acid accounting for 0.5% of the amount of flour used for the second fermentation are added and kneaded evenly, and the dough is fermented for the second time at a temperature of 38°C for 45 minutes. After the second fermentation is completed, the dough is baked at a temperature of 180°C for 45 minutes, and then the baked dough is dried at a temperature of 110°C for 1.8 hours. The dried dough is crushed and passed through a 20-mesh sieve to obtain a filling material;

[0069] (3) Preparation of koji

[0070] The rice is ground, passed through a 40-mesh sieve, and sterilized in an oven at 110°C for 30 minutes to obtain rice flour. The rice flour, filler material, mother koji, and water are mixed in a weight ratio of 12:2:0.70:40, stirred evenly, and formed into koji balls with a diameter of 3 cm. The balls are then incubated at 30°C for 3 days, with the koji turned every 10 hours. Once the balls are evenly covered with mycelium, the koji is ventilated and air-dried until the moisture content in the balls is reduced to less than 12%, thereby obtaining the finished koji. The mother koji contains fungi including Rhizopus and yeast.

[0071] In step (1), during the impregnation, the volume ratio of DM-301 macroporous adsorption resin, SiO2 aerogel and β-phenylethanol solution is 2:2:15.

[0072] In the step (2), the amount of water added during the first fermentation is 65% of the weight of the total flour, the amount of edible yeast added is 0.7% of the weight of the total flour, and the amount of acetic acid added is 0.2% of the amount of flour used for the first fermentation.

[0073] The amounts of Rhizopus and yeast in the mother koji of step (3) are 0.20% and 0.030% of the weight of the mother koji respectively.

[0074] Example 5

[0075] The difference from Example 3 is that the mass concentration of the β-phenylethanol solution is changed to 2.5%, and the other steps and components remain unchanged.

[0076] A method for preparing distiller's yeast for rice wine production comprises the following steps:

[0077] (1) Pretreatment of adsorption and filling materials

[0078] First, the DM-301 macroporous adsorption resin was soaked in anhydrous ethanol for 4.5 hours and washed with pure water until there was no ethanol smell. Then, the DM-301 macroporous adsorption resin and SiO2 aerogel were immersed in a β-phenylethanol solution with a mass concentration of 2.5% for 22 hours. After the impregnation, the resin was dried at 60°C for 1.5 hours to obtain the pretreated DM-301 macroporous adsorption resin and SiO2 aerogel.

[0079] (2) Preparation of filling materials

[0080] The pretreated DM-301 macroporous adsorption resin and SiO2 aerogel obtained in step (1) are crushed respectively, and the DM-301 macroporous adsorption resin and SiO2 aerogel are mixed at a mass ratio of 4:6 to obtain a pretreated mixed material; flour, water, edible yeast and acetic acid accounting for 80% of the mass of the pretreated mixed material are added to the pretreated mixed material, and the mixture is kneaded evenly into a dough, and the dough is fermented for the first time at a temperature of 27°C for 55 minutes; after the first fermentation is completed, the dough is kneaded for 18 minutes to expel the gas in the dough; flour accounting for 20% of the mass of the pretreated mixed material and lactic acid accounting for 0.5% of the amount of flour used for the second fermentation are added and kneaded evenly, and the dough is fermented for the second time at a temperature of 38°C for 45 minutes. After the second fermentation is completed, the dough is baked at a temperature of 180°C for 45 minutes, and then the baked dough is dried at a temperature of 110°C for 1.8 hours. The dried dough is crushed and passed through a 20-mesh sieve to obtain a filling material;

[0081] (3) Preparation of koji

[0082] The rice is ground, passed through a 40-mesh sieve, and sterilized in an oven at 110°C for 30 minutes to obtain rice flour. The rice flour, filler material, mother koji, and water are mixed in a weight ratio of 12:2:0.70:40, stirred evenly, and formed into koji balls with a diameter of 3 cm. The balls are then incubated at 30°C for 3 days, with the koji turned every 10 hours. Once the balls are evenly covered with mycelium, the koji is ventilated and air-dried until the moisture content in the balls is reduced to less than 12%, thereby obtaining the finished koji. The mother koji contains fungi including Rhizopus and yeast.

[0083] In step (1), during the impregnation, the volume ratio of DM-301 macroporous adsorption resin, SiO2 aerogel and β-phenylethanol solution is 2:2:15.

[0084] In the step (2), the amount of water added during the first fermentation is 65% of the weight of the total flour, the amount of edible yeast added is 0.7% of the weight of the total flour, and the amount of acetic acid added is 0.2% of the amount of flour used for the first fermentation.

[0085] The amounts of Rhizopus and yeast in the mother koji of step (3) are 0.20% and 0.030% of the weight of the mother koji respectively.

[0086] Example 6

[0087] The difference from Example 3 is that DM-301 macroporous adsorption resin and SiO2 aerogel are mixed in a mass ratio of 4:15, and the other steps and components remain unchanged.

[0088] A method for preparing distiller's yeast for rice wine production comprises the following steps:

[0089] (1) Pretreatment of adsorption and filling materials

[0090] First, the DM-301 macroporous adsorption resin was soaked in anhydrous ethanol for 4.5 hours and washed with pure water until there was no ethanol smell. Then, the DM-301 macroporous adsorption resin and SiO2 aerogel were immersed in a β-phenylethanol solution with a mass concentration of 1.1% for 22 hours. After the impregnation, the resin was dried at 60°C for 1.5 hours to obtain the pretreated DM-301 macroporous adsorption resin and SiO2 aerogel.

[0091] (2) Preparation of filling materials

[0092] The pretreated DM-301 macroporous adsorption resin and SiO2 aerogel obtained in step (1) are crushed respectively, and the DM-301 macroporous adsorption resin and SiO2 aerogel are mixed at a mass ratio of 4:15 to obtain a pretreated mixed material; flour, water, edible yeast and acetic acid accounting for 80% of the mass of the pretreated mixed material are added to the pretreated mixed material, and the mixture is kneaded evenly into a dough, and the dough is fermented for the first time at a temperature of 27°C for 55 minutes; after the first fermentation is completed, the dough is kneaded for 18 minutes to expel gas in the dough; flour accounting for 20% of the mass of the pretreated mixed material and lactic acid accounting for 0.5% of the amount of flour used for the second fermentation are added and kneaded evenly, and the dough is fermented for the second time at a temperature of 38°C for 45 minutes. After the second fermentation is completed, the dough is baked at a temperature of 180°C for 45 minutes, and then the baked dough is dried at a temperature of 110°C for 1.8 hours. The dried dough is crushed and passed through a 20-mesh sieve to obtain a filling material;

[0093] (3) Preparation of koji

[0094] The rice is ground, passed through a 40-mesh sieve, and sterilized in an oven at 110°C for 30 minutes to obtain rice flour. The rice flour, filler material, mother koji, and water are mixed in a weight ratio of 12:2:0.70:40, stirred evenly, and formed into koji balls with a diameter of 3 cm. The balls are then incubated at 30°C for 3 days, with the koji turned every 10 hours. Once the balls are evenly covered with mycelium, the koji is ventilated and air-dried until the moisture content in the balls is reduced to less than 12%, thereby obtaining the finished koji. The mother koji contains fungi including Rhizopus and yeast.

[0095] In step (1), during the impregnation, the volume ratio of DM-301 macroporous adsorption resin, SiO2 aerogel and β-phenylethanol solution is 2:2:15.

[0096] In the step (2), the amount of water added during the first fermentation is 65% of the weight of the total flour, the amount of edible yeast added is 0.7% of the weight of the total flour, and the amount of acetic acid added is 0.2% of the amount of flour used for the first fermentation.

[0097] The amounts of Rhizopus and yeast in the mother koji of step (3) are 0.20% and 0.030% of the weight of the mother koji respectively.

[0098] Example 7

[0099] The difference from Example 3 is that DM-301 macroporous adsorption resin and SiO2 aerogel are mixed at a mass ratio of 12:6, and the other steps and components remain unchanged.

[0100] A method for preparing distiller's yeast for rice wine production comprises the following steps:

[0101] (1) Pretreatment of adsorption and filling materials

[0102] First, the DM-301 macroporous adsorption resin was soaked in anhydrous ethanol for 4.5 hours and washed with pure water until there was no ethanol smell. Then, the DM-301 macroporous adsorption resin and SiO2 aerogel were immersed in a β-phenylethanol solution with a mass concentration of 1.1% for 22 hours. After the impregnation, the resin was dried at 60°C for 1.5 hours to obtain the pretreated DM-301 macroporous adsorption resin and SiO2 aerogel.

[0103] (2) Preparation of filling materials

[0104] The pretreated DM-301 macroporous adsorption resin and SiO2 aerogel obtained in step (1) are crushed respectively, and the DM-301 macroporous adsorption resin and SiO2 aerogel are mixed at a mass ratio of 12:6 to obtain a pretreated mixed material; flour, water, edible yeast and acetic acid accounting for 80% of the mass of the pretreated mixed material are added to the pretreated mixed material, and the mixture is kneaded evenly into a dough, and the dough is fermented for the first time at a temperature of 27°C for 55 minutes; after the first fermentation is completed, the dough is kneaded for 18 minutes to expel gas in the dough; flour accounting for 20% of the mass of the pretreated mixed material and lactic acid accounting for 0.5% of the amount of flour used for the second fermentation are added and kneaded evenly, and the dough is fermented for the second time at a temperature of 38°C for 45 minutes. After the second fermentation is completed, the dough is baked at a temperature of 180°C for 45 minutes, and then the baked dough is dried at a temperature of 110°C for 1.8 hours. The dried dough is crushed and passed through a 20-mesh sieve to obtain a filling material;

[0105] (3) Preparation of koji

[0106] The rice is ground, passed through a 40-mesh sieve, and sterilized in an oven at 110°C for 30 minutes to obtain rice flour. The rice flour, filler material, mother koji, and water are mixed in a weight ratio of 12:2:0.70:40, stirred evenly, and formed into koji balls with a diameter of 3 cm. The balls are then incubated at 30°C for 3 days, with the koji turned every 10 hours. Once the balls are evenly covered with mycelium, the koji is ventilated and air-dried until the moisture content in the balls is reduced to less than 12%, thereby obtaining the finished koji. The mother koji contains fungi including Rhizopus and yeast.

[0107] In step (1), during the impregnation, the volume ratio of DM-301 macroporous adsorption resin, SiO2 aerogel and β-phenylethanol solution is 2:2:15.

[0108] In the step (2), the amount of water added during the first fermentation is 65% of the weight of the total flour, the amount of edible yeast added is 0.7% of the weight of the total flour, and the amount of acetic acid added is 0.2% of the amount of flour used for the first fermentation.

[0109] The amounts of Rhizopus and yeast in the mother koji of step (3) are 0.20% and 0.030% of the weight of the mother koji respectively.

[0110] Comparative Example 1

[0111] The difference from Example 3 is that DM-301 macroporous adsorption resin is not added, and the other steps and components remain unchanged.

[0112] Comparative Example 2

[0113] The difference from Example 3 is that no SiO2 aerogel is added, and the other steps and components remain unchanged.

[0114] Comparative Example 3

[0115] The koji is made using traditional technology, and the preparation materials are: 150g of hot polygonum multiflorum, 1200g of rice, and 10g of mother koji.

[0116] The process is as follows: rice, Polygonum hydropiper → crushing → adding water and mother koji → mixing and forming → cultivating bacteria → finished koji

[0117] Experimental Example 1 Parameter Index Test of Yeast

[0118] 1.1 Test Method

[0119] Experimental materials: the distiller's yeast prepared in Example 3;

[0120] Sensory test: Grind the koji sample into powder, take an appropriate amount of the sample and pour it onto a standard white board (the white board should meet the requirements of JJG453). Under sufficient light, observe the color, appearance, presence of impurities, and smell its odor;

[0121] Moisture: Determined according to the method specified in GB5009.3;

[0122] Test rice brewing time: Weigh 6.00g of koji (crushed) and evenly sprinkle it onto 1700-1900g of glutinous rice (steamed and cooled to 30-32°C). Mix thoroughly and divide the mixture into four clean containers, controlling the thickness to no more than 5cm. Gently compact the rice layer to create a well (about 3cm in diameter). Then, place the container in an incubator at 29-31°C. The timer starts at h1, the moment the glutinous rice enters the incubator, and ends at h2, the moment the brewing liquid appears in the well in the middle of the rice. The number of days incubation, n, is calculated (hours exceeding 30 seconds are counted as one minute). The calculation formula is: h = h2 - h1 + 24n.

[0123] Sugar content and acidity are determined according to the method specified in QB / T 4577-2013;

[0124] Total arsenic is determined according to GB / T 5009.11;

[0125] Total lead is determined according to GB / T 5009.12;

[0126] Salmonella, Shigella and Staphylococcus aureus shall be tested according to the methods specified in GB 4789.4, GB 4789.5 and GB4789.10 respectively.

[0127] 1.2 Test Results

[0128] The results are shown in Tables 1 and 2.

[0129] Table 1 Sensory test

[0130] project Require Example 3 Color Milky white to light yellow milky odor Fresh fragrance, with unique aroma of the product Fresh fragrance, with the unique aroma of Xiaoqu state powder or granules particles impurities No foreign matter visible to normal vision No foreign matter visible to normal vision

[0131] Table 2 Test results of parameters of koji

[0132]

[0133] It can be seen from Table 1 and Table 2 that the koji prepared in Example 3 meets the koji testing standards.

[0134] Experimental Example 2 Yeast and Rhizopus Quantity Test

[0135] 2.1 Experimental materials: the distiller's yeast prepared in Examples 1 to 5 and Comparative Example 1;

[0136] 2.2 Test method: Test according to the method specified in the 2020 edition of the "Chinese Pharmacopoeia" Microbial Limit Count-Yeast and Mold.

[0137] 2.3 Test Results

[0138] Table 3 Growth of yeast and rhizopus in koji

[0139]

[0140] As can be seen from Table 3, compared with Comparative Example 1, i.e., the traditional process of koji making, the yeast and Rhizopus in the koji prepared in Examples 1 to 5 increased, especially the growth in Example 3 was the most obvious, indicating that although the β-phenylethanol solution is used as an antibacterial agent, the β-phenylethanol solution does not inhibit the growth of yeast and Rhizopus through the innovation of the method of the present invention; by comparing Example 3 with Examples 4 and 5, it can be seen that in order to obtain more yeast and Rhizopus, it is necessary to select an appropriate mass concentration of the β-phenylethanol solution.

[0141] Experimental Example 3 Sensory Evaluation and Flavor Content of Brewed Rice Wine

[0142] 3.1 Experimental Materials

[0143] The distiller's yeast prepared in Example 3, Examples 6-7 and Comparative Examples 1-3;

[0144] 3.2 Experimental methods

[0145] Weigh 1 kg of glutinous rice and place it in a 5 L container. Add 1.5 L of water and soak for 0.5 h. Cook the rice in a rice cooker for 15 min, cool it with cold boiled water to 20-30°C, and filter it through gauze. Add the koji from the experimental materials and mix quickly. Build a nest and seal it with parafilm. Ferment and brew in a 30°C biochemical incubator. Collect the effluent, which is the rice wine, and record the fermentation completion time.

[0146] Sensory evaluation: Ten wine tasters tasted the rice wine obtained above, using color, aroma, flavor, and style (characteristics) as sensory evaluation indicators of the rice wine, with each indicator having a full score of 10 points, and the average of the results was calculated;

[0147] Flavor content: The volatile compounds in rice wine samples were extracted using headspace solid phase microextraction technology, and the extracted compounds were transferred to GC-MS for determination of type and content.

[0148] 3.3 Flavor test results

[0149] The results are shown in Tables 4 and 5:

[0150] Table 4 Sensory evaluation

[0151]

[0152] Table 5 Flavoring substance content and fermentation time

[0153]

[0154] As can be seen from Table 4, after the koji prepared in Example 3 and Examples 6-7 are prepared into rice wine, their sensory evaluation is higher than that of the rice wine prepared by the traditional koji making process in Comparative Example 1. By comparing Example 3 with Examples 6-7 and Comparative Examples 1-2, it can be seen that the effect achieved by mixing DM-301 macroporous adsorption resin and SiO2 aerogel in a mass ratio of 4:6 is better. Increasing the proportion of DM-301 macroporous adsorption resin or SiO2 aerogel not only fails to achieve the best effect, but also increases the brewing cost; if only DM-301 macroporous adsorption resin or SiO2 aerogel is added, it will be not conducive to the growth of dominant microorganisms in the koji due to insufficient loosening of the koji embryo.

[0155] As shown in Table 5, the rice wines prepared in the Examples all have higher flavor content than the Comparative Examples. Adding DM-301 macroporous adsorption resin and SiO2 aerogel in a mass ratio of 4:6 to the koji fully utilizes the relatively dense properties of the macroporous adsorption resin and the relatively loose properties of the SiO2 aerogel. The combination of the two, in an appropriate proportion, facilitates the fermentation of the koji, improves the quality of the rice wine, and shortens the fermentation time. Adding only DM-301 macroporous adsorption resin or SiO2 aerogel can easily result in the filling material being too dense or too loose, leading to waterlogging or a rough, cracked surface of the koji, which can lead to bacterial infiltration. This can also lead to rapid heat loss in the koji, which can affect the growth and reproduction of beneficial microorganisms. Consequently, the fermentation time reduction is not as significant as when DM-301 macroporous adsorption resin and SiO2 aerogel are mixed in proportion.

[0156] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing distiller's yeast for rice wine production, characterized in that: The following steps are involved: (1) Pretreatment of adsorption and filling materials First, DM-301 macroporous adsorption resin is soaked in anhydrous ethanol for 4 to 5 hours, and then washed with pure water until there is no ethanol smell. Then, DM-301 macroporous adsorption resin and SiO2 aerogel are respectively immersed in a β-phenylethanol solution with a mass concentration of 0.11 to 2.5% for 20 to 24 hours. After the immersion is completed, the DM-301 macroporous adsorption resin and SiO2 aerogel are dried to obtain the pretreated DM-301 macroporous adsorption resin and SiO2 aerogel; (2) Preparation of filling materials The pretreated DM-301 macroporous adsorption resin and SiO2 aerogel obtained in step (1) are crushed separately, and the DM-301 macroporous adsorption resin and SiO2 aerogel are mixed at a mass ratio of 3-7:5-10 to obtain a pretreated mixed material; flour, water, edible yeast and acetic acid are added to the pretreated mixed material and kneaded to form a dough, and the dough is fermented for the first time at a temperature of 26-28°C; after the first fermentation is completed, the dough is kneaded for 15-20 minutes to expel gas in the dough; flour and lactic acid are then added and kneaded to obtain a filling material; the dough is fermented for the second time at a temperature of 35-40°C; after the second fermentation is completed, the dough is baked at a temperature of 170-200°C for 30-50 minutes, and then the baked dough is dried, and the dried dough is crushed to obtain a filling material; (3) Preparation of koji Rice flour, filling material, mother koji and water are mixed in a weight ratio of 8-20:1-3:0.35-0.80:20-50, stirred evenly to form koji balls with a diameter of 2-5 cm, cultured in an environment with a temperature of 25-35°C for 2-5 days, turned over every 8-15 hours, and after the mycelium is evenly distributed on the koji balls, ventilated and air-dried until the moisture in the koji balls evaporates to within 12%, thereby obtaining a finished wine koji; the fungi in the mother koji include rhizopus and yeast.

2. The method for preparing distiller's yeast for rice wine production according to claim 1, characterized in that: The mass concentration of the beta-phenylethanol solution is 1.0-1.2%.

3. The method for preparing distiller's yeast for rice wine production according to claim 1, characterized in that: The mass concentration of the β-phenylethanol solution in step (1) is 1.1%, and during the impregnation, the volume ratio of DM-301 macroporous adsorption resin, SiO2 aerogel and β-phenylethanol solution is 1-3:1-3:10-20.

4. The method for preparing distiller's yeast for rice wine production according to claim 1, characterized in that: In step (2), DM-301 macroporous adsorption resin and SiO2 aerogel are mixed in a mass ratio of 4:

6.

5. The method for preparing distiller's yeast for rice wine production according to claim 1, characterized in that: In the step (2), the amount of water added during the first fermentation is 60-70% of the weight of the total flour, the amount of edible yeast added is 0.5-1.0% of the weight of the total flour, the amount of acetic acid added is 0.1-0.3% of the amount of flour used in the first fermentation, and the amount of lactic acid added is 0.3-0.6% of the amount of flour used in the second fermentation. The amount of flour added during the first fermentation is 80% of the weight of the pretreated mixed material, and the amount of flour added during the second fermentation is 20% of the weight of the pretreated mixed material.

6. The method for preparing distiller's yeast for rice wine production according to claim 1, characterized in that: The amounts of Rhizopus and yeast in the mother koji of step (3) are 0.002-0.30% and 0.001-0.040% of the weight of the mother koji respectively.

7. The method for preparing distiller's yeast for rice wine production according to claim 1, characterized in that: In step (1), the drying temperature is controlled at 50-70° C., and the drying time is 1-2 h.

8. The method for preparing distiller's yeast for rice wine production according to claim 1, characterized in that: The first fermentation time is 50-60 minutes, and the second fermentation time is 40-50 minutes.

9. A distiller's yeast for rice wine production, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 8.

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