A strain and its application in preparing chestnut grain fermented beverage

Abstract

The present invention discloses a strain and its application in the preparation of chestnut cereal fermented beverage, and belongs to the field of food processing technology. The present invention uses fresh chestnut and cereal as main raw materials, and adds rice koji prepared by screening strain QJQ-12 (CGMCC No.18834) to co-ferment and prepare chestnut cereal fermented beverage. The cereal fermented beverage is a non-alcoholic cereal fermented beverage (alcohol content <0.4%), and the sugar and acid in the beverage are obtained by fermentation rather than artificially added later. The present invention prepares rice koji by utilizing strain, and co-fermentes the rice koji with chestnut and cereal to prepare fermented beverage. The chestnut starch utilization rate is high, the hydrolysis rate is fast, and it is suitable for promotion and application.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, in particular to a strain and application thereof in preparing a fermented chestnut grain beverage. Background Art

[0002] Chestnuts are native to my country and are one of the oldest and most famous nuts consumed there, with annual production ranking first in the world. Rich in starch, chestnuts also contain monosaccharides and disaccharides, carotene, thiamine, riboflavin, niacin, ascorbic acid, protein, fat, and inorganic salts, making them a good choice for developing starchy beverages. Research has shown that the structure of chestnut starch differs from that of cereal starches, being closer to corn starch in terms of crystal form and gelatinization temperature. Furthermore, when using commercially available sweet wine koji and laboratory-preserved Aspergillus oryzae 2226 and 2011 strains, chestnut utilization rates were low, resulting in waste. Therefore, identifying strains with enhanced chestnut starch degradation capabilities has become a major research and development topic for improving chestnut utilization.

[0003] Furthermore, the most popular beverages currently are carbonated and flavored drinks. These beverages are sterilized and processed by adding flavorings, sugar, sweeteners, and acidifiers to adjust their flavor. From a nutritional perspective, these two types of beverages offer no health benefits other than providing energy. Furthermore, the fermentation of chestnuts into beverages is rarely reported in the industry.

[0004] Therefore, how to provide a strain that can efficiently decompose chestnut grain starch into monosaccharides or oligosaccharides and use the strain to prepare a sweet and sour chestnut grain starch fermented beverage without adding exogenous sweeteners or acidifiers is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention aims to address the problems existing in the prior art by providing a strain and its use in preparing a fermented chestnut-cereal beverage. The fermented chestnut-cereal beverage is a non-alcoholic fermented cereal beverage (alcohol content <0.4%) made from cereals and chestnuts, in which the sugars and acids in the beverage are obtained through fermentation rather than artificially added. The present invention utilizes a selected strain to prepare rice koji, which is then co-fermented with chestnuts and cereals to prepare the fermented beverage. The beverage has a high chestnut starch utilization rate and a fast hydrolysis rate, making it suitable for promotion and application.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A strain, the deposit number of which is CGMCC NO.18834, has been deposited in the General Microbiology Center of the China Culture Collection Administration, referred to as CGMCC, at the Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, with a deposit date of November 11, 2019, and is classified as Aspergillus oryzae.

[0008] Another object of the present invention is to provide the use of the above-mentioned strain in the preparation of chestnut grain fermented beverages, and the rice koji prepared by the strain is used to prepare chestnut grain fermented beverages.

[0009] Furthermore, when preparing the chestnut grain fermented beverage, the amount of rice koji added is 10-20%.

[0010] Furthermore, the process for preparing the rice koji using the strain specifically comprises the following steps:

[0011] (1) The strain was inoculated into an eggplant-shaped flask and cultured at 28°C to 34°C for 5 days, during which the humidity was maintained between 40% and 60%. Under aseptic conditions, sterile water was poured onto the Aspergillus oryzae slant and the spore solution was obtained after sufficient shaking.

[0012] (2) Soak the rice in distilled water until the rice grains can be crushed by hand, steam it in a steamer for 15 to 20 minutes, then cool it to room temperature, inoculate the spore liquid obtained in step (1), shake it thoroughly, and culture it at a constant temperature of 28°C. After 24 hours, shake it once and culture it for another 48 hours to obtain rice koji.

[0013] Preferably, the spore liquid inoculation amount in step (2) is 2 mL / 100 g based on the mass of dry rice.

[0014] The present invention also claims protection for the use of the above-mentioned strains to prepare rice koji, and the co-fermentation of the rice koji with chestnuts and grains to prepare chestnut and grain fermented beverage.

[0015] In order to achieve the above object, the technical solution of the present invention is as follows:

[0016] A method for preparing a fermented chestnut beverage comprises the following steps:

[0017] (1) Soak the grains in water and mix them with shelled and crushed chestnuts, steam them, pour them over rice to cool them down, and set aside;

[0018] (2) evenly sprinkling the rice koji prepared from the strain as claimed in claim 1 on the chestnut grain rice obtained in step (2), and stirring evenly to obtain a mixture;

[0019] (3) putting the chestnut grain rice mixed with rice koji in step (2) into a vat to build a nest and cultivate bacteria, then adding water to the mixture, stirring, and fermenting to obtain chestnut grain fermentation liquid for later use;

[0020] Among them, before putting the fermentation tank into the tank and making the nest, the fermentation tank and tools need to be carefully cleaned, and then scalded with boiling water for 40 to 60 minutes. After the tank cools down, the raw materials mixed with koji are put into the tank and gently compacted to make a "U"-shaped nest in the middle to allow the juice to seep out.

[0021] (4) crushing the chestnut grain fermentation liquid obtained in step (3) to obtain fermented milk, filling and sterilizing, and obtaining a chestnut grain fermented beverage.

[0022] The present invention uses chestnuts and grains as main raw materials, which are mixed and steamed, then spread out to cool and mixed with rice koji. The amylase system and protease system in the rice koji are used to degrade the starch and protein in the raw materials into sugars, amino acids, peptides and other substances. The degree of starch degradation is controlled by controlling the fermentation time. At the same time, under semi-open fermentation conditions, the acidity of the product is given by the growth of lactic acid bacteria. By controlling the fermentation cycle, a chestnut and grain fermented beverage that is sweet and sour without any preparation can be obtained.

[0023] Preferably, in step (1), the mass ratio of the grains to water is 1:2, and the soaking time is 12 to 24 hours.

[0024] It should be noted that the soaking time of grains is related to the seasonal temperature. In summer, grains can be soaked for 12 hours, while in winter, the soaking time can be up to 24 hours. The particle size of chestnuts after shelling and crushing should be controlled at 3 to 4 cm.

[0025] Furthermore, the steaming process is as follows: steam the rice for 15 minutes after steam is generated, then take out the rice, pour cold boiled water over the rice, drain the water and steam it again, and steam it for another 30 minutes after steam is generated; after the rice is steamed, rinse it with water, and spread it out to cool it down to 30°C to 40°C.

[0026] The above steaming (cooking) requires that the rice grains are loose, without a hard core, and cooked through but not mushy.

[0027] Preferably, in step (2), the amount of rice koji added is 10-20%.

[0028] Furthermore, the above rice koji is prepared by inoculating strains screened by the inventors, and the rice koji is a finished commercially available wine koji, and its addition amount is 0.5-1.0%.

[0029] Preferably, in step (3), the incubation temperature is 25° C. to 35° C., and the incubation time is 12 to 24 hours.

[0030] Furthermore, the amount of water added is 1 to 4 times the total weight of the chestnut grains, and the fermentation time is 40 to 64 hours.

[0031] It should be noted that when white mycelium appears and a small amount of juice precipitates out of the dimples, add boiled water.

[0032] Preferably, in step (4), a stabilizer is added according to actual needs; wherein, the stabilizer is a mixture of carrageenan and xanthan gum in a ratio of 1:1, and the stabilizer is 0.1% (w / v) of the volume of the chestnut grain fermentation liquid.

[0033] The technical effect of adding the stabilizer is to prevent stratification. It is also possible to obtain a fermented grain beverage with natural stratification without adding the stabilizer, and then the fermented milk can be pasteurized and filled.

[0034] Preferably, the cereal is at least one of rice, millet, corn, coix seed, sorghum rice, and glutinous rice, and the mass of the cereal accounts for 60-90% of the total mass of the raw materials, and the mass of the chestnut accounts for 10-40% of the total mass of the raw materials.

[0035] It can be seen from the above technical solutions that, compared with the prior art, the present invention provides a strain and its application in the preparation of chestnut grain fermented beverages, which has the following excellent effects:

[0036] (1) The present invention screened out a strain of Aspergillus oryzae QJQ-12 (CGMCC No. 18834) that can efficiently utilize chestnut starch, and used chestnut and grain as the main raw materials, added rice koji prepared by the screened strain to co-ferment and prepare chestnut and grain fermented beverage.

[0037] (2) The present invention utilizes the amylase system of Aspergillus oryzae to hydrolyze the raw starch into monosaccharides or oligosaccharides to form a sweetener, and utilizes the lactic acid secreted by the lactic acid bacteria in the natural network during the fermentation process as an acidulant. By controlling the fermentation time and fermentation temperature to adjust the sugar-acid ratio of the fermented beverage, a chestnut starch beverage with excellent taste and rich nutritional value is prepared. DETAILED DESCRIPTION

[0038] The following will clearly and completely describe the technical solutions described in the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0039] The present invention discloses a strain and its application in preparing a fermented chestnut grain beverage. Rice koji prepared by the self-screened strain QJQ-12 (CGMCC No. 18834) is used to ferment the chestnut grain beverage, thereby improving the utilization rate of chestnut starch and reducing waste. The prepared fermented chestnut grain beverage can be sweet and sour without any mixing.

[0040] For a better understanding of the present invention, the present invention is further specifically described below through the following examples, but it should not be understood as limiting the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above invention content are also considered to fall within the scope of protection of the present invention.

[0041] A bacterial strain, the deposit number of which is CGMCC NO.18834.

[0042] The present invention seeks to protect the use of the above-mentioned strain in preparing chestnut grain fermented beverages, and the rice koji prepared from the above-mentioned strain is used to prepare chestnut grain fermented beverages.

[0043] When preparing the fermented chestnut grain beverage, the added amount of the rice koji is 10-20%.

[0044] Furthermore, the process for preparing the rice koji using the strain specifically comprises the following steps:

[0045] (1) Inoculate the strain into an eggplant-shaped flask with an inoculating spatula and culture at 28°C to 34°C for 5 days. During this period, the humidity of the environment is maintained between 40% and 60%. Under sterile conditions, sterile water is poured into the Aspergillus oryzae slant and shaken thoroughly to obtain a spore solution. The spore concentration after detection is 1.0×10 7 / mL;

[0046] (2) Weigh 50 g of rice and put it into a 250 mL Erlenmeyer flask, add 50 mL of distilled water, and soak for 12 to 24 hours. After soaking until the rice grains can be crushed by hand, steam it in a steamer for 15 to 20 minutes, and judge it as the product with no hard core when pinched by hand; cool it to room temperature, inoculate it with the above-mentioned spore liquid (inoculation amount is 2 mL / 100 g, based on the weight of dry rice), shake it thoroughly, and culture it at a constant temperature of 28°C. Shake it once after 24 hours and culture it for another 48 hours to obtain rice koji.

[0047] In addition, the present invention also protects a method for preparing rice koji using the above-mentioned strain, and fermenting the rice koji with chestnuts and grains to prepare a chestnut and grain fermented beverage, which specifically includes the following steps:

[0048] 1. Raw material selection: grains (rice, millet, corn, barley, sorghum rice, glutinous rice, etc.), chestnuts (fresh chestnuts from the current year, or crushed chestnut kernels from the processing process, or small chestnuts of substandard quality);

[0049] 2. Soak the grains (grain: water = 1:2) for 12 hours in summer and 24 hours in winter, then drain the water; shell the chestnuts and crush them into particles of 3-4 cm in size;

[0050] 3. Raw material mixing: Mix chestnuts and grains. The weight of chestnuts can account for 10-40% of the total weight of the raw materials. The weight of grains can be one type or multiple types in any proportion, and their weight accounts for 60-90% of the total weight of the raw materials.

[0051] 4. Steaming: After mixing the ingredients, steam the rice in a steamer for 15 minutes. Take out the rice with the cloth, pour cold boiled water on the rice, drain the water and put it back into the steamer. Steam for another 30 minutes after the rice is steamed and turn off the heat. The rice should be loose, without a hard core, and cooked through but not mushy.

[0052] 5. Sprinkle the rice and let it air dry: After the chestnut grain rice is steamed, rinse it with cold boiled water to separate the rice grains and spread it out with utensils to cool it down to 30℃~40℃ (around 35℃);

[0053] 6. Mixing koji: Sprinkle the rice koji evenly on the cooled rice, add a small amount of cold boiled water and stir evenly. The rice koji we use is the commercially available sweet wine koji (mainly Rhizopus) and the rice koji inoculated with Aspergillus oryzae (QJQ-12) cultured in our own laboratory; Among them, the amount of finished commercial sweet wine koji is 0.5-1%, and the amount of self-made rice koji added is 10-20%;

[0054] 7. Place the fermentation vat and tools in the vat before placing it in the vat: Clean the fermentation vat and tools thoroughly before placing them in the vat. Then, scald them in boiling water for 40-60 minutes. After the vat cools down, put the mixed ingredients into the vat and gently compact them to create a "U"-shaped cavity in the middle to allow the juice to seep out.

[0055] 8. Saccharification and fermentation: Control the temperature between 25℃ and 35℃ (around 30℃) and culture for 12-24 hours. When white mycelium appears and a small amount of juice precipitates in the dimples, add boiled water with the amount of water being 1-4 times the mass of the initial raw materials (the total mass of the chestnut grains). Continue to culture for 40-64 hours. The chestnut grain fermented beverage is fermented to maturity.

[0056] 9. Beating and sterilization: The obtained chestnut grain fermented beverage is prepared by using a beater to thoroughly beat the remaining rice grains and chestnuts to obtain fermented milk. A stabilizer can be added to prevent stratification according to actual needs, or a naturally stratified fermented grain beverage can be obtained without adding a stabilizer. The fermented milk is then pasteurized and filled. The stabilizer to prevent stratification is a mixture of carrageenan and xanthan gum in a ratio of 1:1, and the stabilizer is 0.1% (w / v) of the volume of the chestnut grain fermented liquid.

[0057] The technical solution of the present invention will be further described below in conjunction with specific experiments.

[0058] It should be noted that the content of the present invention is not limited to the content of the following experimental examples.

[0059] A method for preparing a fermented chestnut grain beverage, taking chestnut glutinous rice as an example, specifically comprises the following steps:

[0060] (1) The raw materials are selected from grains (rice, millet, corn, barley, sorghum rice, glutinous rice, etc.) and chestnuts (fresh chestnuts produced in the current year, or crushed chestnut kernels in the process of processing chestnut kernels, or small chestnuts of substandard quality);

[0061] (2) Ratio of chestnuts to grains: chestnuts can account for 10-40% of the total raw material mass, and grains can be one or more grains in any proportion, accounting for 60-90% of the total raw material mass;

[0062] (3) Amount of koji added: The amount of commercially available sweet koji is 0.5-1%, and the amount of homemade rice koji is 10-20%;

[0063] (4) Saccharification temperature and time: Control the temperature at 25°C to 35°C (around 30°C) and incubate for 12-24 hours; add 1-4 times the mass of the initial raw material of boiled water and continue incubating for 40-64 hours. The chestnut grain fermented beverage can be fermented to maturity.

[0064] Among them, the following Examples 1 to 10 all disclose chestnut glutinous rice fermented beverages prepared using the above-mentioned preparation method, and the process parameters and the quality content (total acid, total sugar, total phenols and total flavonoids) of the final product (chestnut glutinous rice fermented beverage) are as follows:

[0065] Example 1:

[0066] A chestnut and glutinous rice fermented beverage is prepared by fermenting at 30°C for 24 hours at a ratio of 1:5 chestnut to glutinous rice, adding 0.5% of the mass of the initial raw materials to commercially available koji, and using a total mass of the initial raw materials to water ratio of 1:2. The beverage has a total sugar content of 73.77 g / L, a total acid content of 1.25 g / L (calculated as lactic acid), a total phenol content of 187.1 μg / mL, and a total flavonoid content of 106.5 μg / mL.

[0067] Example 2:

[0068] A chestnut and glutinous rice fermented beverage is prepared by fermenting at a ratio of 1:10 chestnut to glutinous rice, adding 0.5% of the mass of the initial raw materials to commercially available koji, and using a total mass of the initial raw materials to water ratio of 1:2. The beverage is fermented at 30°C for 24 hours, and water is added for another 24 hours to obtain the beverage. The beverage has a total sugar content of 78.13 g / L, a total acid content of 1.29 g / L (calculated as lactic acid), a total phenol content of 98.3 μg / mL, and a total flavonoid content of 65.3 μg / mL.

[0069] Example 3:

[0070] A chestnut and glutinous rice fermented beverage is prepared by fermenting at 30°C for 24 hours with water added at a ratio of 1:5, adding QJQ-12 distiller's yeast (QJQ-12) at 20% of the initial raw material mass, and a total raw material mass:water ratio of 1:2. The beverage has a total sugar content of 107.42 g / L, a total acid content of 1.52 g / L (calculated as lactic acid), a total phenol content of 201.3 μg / mL, and a total flavonoid content of 149.6 μg / mL.

[0071] Example 4:

[0072] A chestnut and glutinous rice fermented beverage is prepared by fermenting at 30°C for 24 hours at a ratio of 1:10, adding QJQ-12 distiller's yeast (QJQ-12) at a ratio of 20% of the initial raw material mass to water at a ratio of 1:2. The beverage has a total sugar content of 118.51 g / L, a total acid content of 1.60 g / L (calculated as lactic acid), a total phenol content of 115.23 μg / mL, and a total flavonoid content of 75.81 μg / mL.

[0073] Example 5:

[0074] A chestnut and glutinous rice fermented beverage is prepared by fermenting at 30°C for 24 hours with water added for another 24 hours. The beverage has a total sugar content of 52.21 g / L, a total acid content of 0.75 g / L (calculated as lactic acid), a total phenol content of 83.26 μg / mL, and a total flavonoid content of 43.21 μg / mL.

[0075] Example 6:

[0076] A chestnut and glutinous rice fermented beverage is prepared by fermenting at 30°C for 24 hours at a ratio of 1:10, adding 0.5% of the mass of the initial raw materials to commercially available koji, and a total mass of the initial raw materials to water ratio of 1:4. The beverage has a total sugar content of 60.01 g / L, a total acid content of 0.62 g / L (calculated as lactic acid), a total phenol content of 69.34 μg / mL, and a total flavonoid content of 39.26 μg / mL.

[0077] Example 7:

[0078] A chestnut and glutinous rice fermented beverage is prepared by fermenting at 30°C for 24 hours at a ratio of 1:5, adding QJQ-12 distiller's yeast (QJQ-12) at a ratio of 20% of the initial raw material mass, and a ratio of 1:4 of total initial raw material mass to water. The beverage has a total sugar content of 60.25 g / L, a total acid content of 0.56 g / L (calculated as lactic acid), a total phenol content of 110.23 μg / mL, and a total flavonoid content of 80.3 μg / mL.

[0079] Example 8:

[0080] A chestnut and glutinous rice fermented beverage is prepared by fermenting at 28°C for 24 hours, adding water, and continuing to ferment for another 24 hours. The beverage has a total sugar content of 55.25 g / L, a total acid content of 0.58 g / L (calculated as lactic acid), a total phenol content of 101.32 μg / mL, and a total flavonoid content of 78.4 μg / mL.

[0081] Example 9:

[0082] A chestnut and glutinous rice fermented beverage is prepared by fermenting at 28°C for 30 hours, adding water, and continuing fermentation for 24 hours at a ratio of 1:5 chestnut to glutinous rice, 20% of the mass of the initial raw materials, and 1:4 total mass of the initial raw materials to water. The beverage has a total sugar content of 61.16 g / L, a total acid content of 0.60 g / L (calculated as lactic acid), a total phenol content of 111.34 μg / mL, and a total flavonoid content of 80.6 μg / mL.

[0083] Example 10:

[0084] A chestnut and coix seed fermented beverage is prepared by fermenting at 30°C for 24 hours in a ratio of 1:5, adding 0.5% of the weight of the initial raw materials to commercially available steamed rice koji, and adding 1:2 of the total weight of the initial raw materials to water. The beverage has a total sugar content of 69.35 g / L, a total acid content of 1.55 g / L (calculated as lactic acid), a total phenol content of 205.25 μg / mL, and a total flavonoid content of 114.35 μg / mL.

[0085] In addition, in order to further verify the properties of the chestnut grain fermented beverage prepared by fermenting rice koji prepared by using the screened strain QJQ-12 of the present invention with cereals and chestnuts, the inventors also conducted the following comparative experimental analysis:

[0086] 1. Determination of chestnut starch utilization

[0087] 100g chestnut kernels were crushed into small pieces with a particle size of about 3-4mm, steamed and cooled, and then added with boiled water at a ratio of 1:1. Then, koji prepared with QJQ-12, Aspergillus oryzae 2226, and Aspergillus oryzae 2011 were added at a ratio of 5g / 100g rice, and Angel sweet koji was added at 0.2% (w / w). After hydrolysis at 28℃ for 3h, the supernatant was removed by centrifugation, and the precipitate was completely removed and dried at 80℃ to measure the dry weight. The chestnut starch utilization rate was measured according to the weight of the remaining precipitate, and the total sugar content in the supernatant was measured at the same time. The results are shown in Table 2.

[0088] Among them, the enzyme activity comparison of rice koji obtained from QJQ-12, sweet wine koji, and finished koji obtained from existing Aspergillus oryzae 2226 and 2011 is shown in Table 1:

[0089] Table 1 Comparison of three enzyme activities

[0090] QJQ-12 2011 2226 sweet wine yeast Amylase activity (U / g dry weight) 1098.35 1102.12 967.21 1228.12 Glucoamylase activity (U / g dry weight) 246.27 134.20 192.16 112.12 Protease activity (U / g dry weight) 908.32 562.13 779.12 945.36

[0091] Table 2 Utilization rate of chestnut starch

[0092] QJQ-12 2011 2226 sweet wine yeast Chestnut utilization rate (%) 67.21 45.36 37.46 29.89 Reducing sugar content (g / 100mL) 36.34 21.34 16.21 12.68

[0093] As shown in Table 1, the amylase activity of the preserved strain QJQ-12 was lower than that of sweet wine koji and Aspergillus oryzae 2011, but its saccharification enzyme activity was higher than that of the other three kojis, and its protease activity was also high. Table 2 shows that the chestnut utilization rate of the preserved strain QJQ-12 was the highest, reaching 67.21%, within the same saccharification time, and the reducing sugar content of the hydrolyzate was 36.34 g / 100 mL.

[0094] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An application of Aspergillus oryzae in the preparation of a non-alcoholic chestnut grain fermented beverage, characterized in that: The rice koji prepared from the Aspergillus oryzae strain with a preservation number of CGMCC NO.18834 is used to prepare a non-alcoholic fermented chestnut grain beverage; The process for preparing the rice koji using the strain specifically comprises the following steps: (1) Inoculate Aspergillus oryzae into an eggplant-shaped flask and culture at 28°C–34°C for 5 days, maintaining the humidity between 40% and 60%. Pour sterile water onto the Aspergillus oryzae slant under aseptic conditions and shake thoroughly to obtain a spore solution. (2) Soak the rice in distilled water until the rice grains can be crushed by hand, steam it in a steamer for 15-20 minutes, then cool it to room temperature, inoculate the spore liquid obtained in step (1), shake it thoroughly, and culture it at a constant temperature of 28°C. Shake it once after 24 hours and culture it for another 48 hours to obtain rice koji.

2. The use of an Aspergillus oryzae species according to claim 1 in preparing a non-alcoholic chestnut grain fermented beverage, characterized in that When preparing the non-alcoholic chestnut grain fermented beverage, the added amount of the rice koji is 10-20%.

3. The use of an Aspergillus oryzae species according to claim 1 in preparing a non-alcoholic chestnut grain fermented beverage, characterized in that: The spore liquid inoculation amount in step (2) is 2 mL / 100 g based on the mass of dry rice.

4. A method for preparing a non-alcoholic chestnut grain fermented beverage, characterized in that: The method comprises preparing rice koji using the Aspergillus oryzae strain according to claim 1, and fermenting the rice koji with chestnuts and grains to prepare a non-alcoholic chestnut and grain fermented beverage; the method specifically comprises the following steps: (1) Soak the grains in water and mix with shelled and crushed chestnuts, steam, pour over rice to cool, and set aside; (2) evenly sprinkling the rice koji prepared from the Aspergillus oryzae strain as described in claim 1 on the chestnut grain rice obtained in step (2), and stirring the mixture to obtain a mixture; (3) Put the chestnut grain rice mixed with rice koji in step (2) into a vat to build a nest and cultivate bacteria, then add water to the mixture, stir, and ferment to obtain chestnut grain fermentation liquid for later use; (4) The chestnut grain fermented liquid obtained in step (3) is crushed to obtain fermented milk, which is then bottled and sterilized to obtain a non-alcoholic chestnut grain fermented beverage.

5. The method for preparing a non-alcoholic fermented chestnut beverage according to claim 4, characterized in that: In the step (1), the mass ratio of the grain to water is 1:2, and the soaking time is 12 to 24 hours; and the specific steaming process is: steam the rice for 15 minutes after steam is generated, then take out the rice, pour cold boiled water over the rice, drain the water and steam it again, and steam it for another 30 minutes after steam is generated; after the rice is steamed, rinse it with water, spread it out and cool it to 30°C to 40°C.

6. The method for preparing a non-alcoholic fermented chestnut beverage according to claim 4, characterized in that: In the step (2), the amount of rice koji added is 10-20%.

7. The method for preparing a non-alcoholic fermented chestnut beverage according to claim 4, characterized in that: In the step (3), the incubation temperature is 25°C to 35°C, the incubation time is 12 to 24 hours, and the amount of water added is 1 to 4 times the total weight of the chestnut grains, and the fermentation time is 40 to 64 hours.

8. The method for preparing a non-alcoholic fermented chestnut beverage according to any one of claims 4 to 7, characterized in that: The cereal is at least one of rice, millet, corn, coix seed, sorghum rice, and glutinous rice, and the mass of the cereal accounts for 60-90% of the total mass of the raw materials, and the mass of the chestnut accounts for 10-40% of the total mass of the raw materials.