Application of Eurotium cristatum NCPS2018015 in the Fermentation Preparation of Tea Drinks

Abstract

The present invention belongs to the technical field of microbial fermented tea, and particularly relates to the application of Eurotium cristatum NCPS2018015 in the fermentation for preparing tea drinks. The present invention uses the specially preserved Eurotium cristatum NCPS2018015 to ferment Acer truncatum seeds, and then dries and shapes the fermented material to make Acer truncatum seed tea drinks. Specifically, the application of the present invention includes the following steps: (1) Pretreatment of Acer truncatum seeds; (2) Preparation of Eurotium cristatum NCPS2018015 spore suspension; (3) Fermentation of Acer truncatum seeds; (4) Drying and shaping of Acer truncatum seed tea. Different from the traditional use of Acer truncatum seeds to process oil products, the present invention develops a new use of Acer truncatum seeds as tea products for daily drinking. After fermentation with Eurotium cristatum NCPS2018015, the bioactive components in Acer truncatum seed tea, such as plant soluble sugars and flavonoids, are significantly higher than those in the unfermented Acer truncatum seed raw materials. The obtained fermented tea drink has a bright appearance color after brewing, showing a yellowish-brown color, with a mellow taste and no bitter or astringent taste.

Description

Technical Field

[0001] The present invention belongs to the technical field of microbial fermented tea, and particularly relates to the application of Eurotium cristatum NCPS2018015 in the fermentation for preparing tea drinks. Background Art

[0002] Acer truncatum Bunge, a plant of the genus Acer, is named after the shape of its samara which resembles the "gold ingot" in ancient China. The seeds of Acer truncatum Bunge, namely Acer truncatum seeds, are rich in oil and protein. In particular, the content of unsaturated fatty acids in them is as high as 90%. In addition, the Acer truncatum seed oil also contains 5.8% of the functional fatty acid - nervonic acid, which can repair and dredge the nerve fibers of the damaged brain nerve pathway and promote the regeneration of nerve cells. Therefore, at present, the development of Acer truncatum seeds is mainly to obtain products such as Acer truncatum seed oil through frying and oil pressing.

[0003] However, due to the low oil yield of Acer truncatum seeds and the high cost of oil pressing, the price of Acer truncatum seed oil is expensive, up to 800 - 900 yuan / kg. Therefore, the audience of Acer truncatum seed oil is limited, which further restricts the development and utilization of Acer truncatum seeds.

[0004] At present, there is no other utilization method for Acer truncatum seeds, and the application ways of Acer truncatum seeds are extremely single. Therefore, it is necessary to develop a new application way for Acer truncatum seeds to synchronously improve the utilization rate of other bioactive components on the basis of utilizing the oil components in Acer truncatum seeds. Therefore, it is of great significance to develop an Acer truncatum seed tea that can be used for people's daily drinking and has a more affordable price.

[0005] However, due to the high oil content in Acer truncatum seeds and the low content of available sugar and protein, and the fact that common commercially available microbial strains are difficult to directly use it as a substrate for fermentation, the fermentation is not sufficient and the fermentation effect is poor. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention provides an application of Eurotium cristatum NCPS2018015 in the fermentation for preparing tea drinks.

[0007] In the above application provided by the present invention, the tea drink is a related tea product of Acer truncatum seed tea, including any one of Acer truncatum seed tea bags, tea cakes, and brick teas.

[0008] Eurotium cristatum, commonly known as "Jinhua fungus", is a fungus belonging to the genus Eurotium in the family Trichocomaceae of the order Eurotiales. It is commonly found growing on dark brick tea. This strain can utilize the nutrients in the raw materials to achieve its own metabolism, and at the same time can secrete extracellular enzymes such as amylase, protease, and oxidase, which can catalyze the conversion of starch in tea leaves into monosaccharides, catalyze the oxidation of polyphenolic compounds, make the tea soup turn brownish-red, and eliminate the rough and green taste. In addition, Jinhua fungus can also produce an enzyme, and the presence of this enzyme can promote the conversion of proteins and tea polyphenols in tea leaves into reddish-brown components, which can not only improve the taste of the tea drink, making it more mellow, refreshing, sweet and smooth with a sweet aftertaste, but also promote digestion, reduce blood lipids, and regulate carbohydrate metabolism.

[0009] The application of Eurotium cristatum NCPS2018015 provided by the present invention in the fermentation preparation of tea drinks is specifically as follows: Eurotium cristatum NCPS2018015 is activated and then prepared into a spore suspension, which is inoculated into a culture medium containing Acer truncatum seeds and fermented to obtain Acer truncatum seed tea.

[0010] The above-mentioned Eurotium cristatum NCPS2018015 was deposited at the China Center for Type Culture Collection on December 12, 2018. The deposit address is: Wuhan University, Wuhan, China. The deposit number is: CCTCC NO: M 2018882, and the taxonomic name is: Eurotium cristatum NCPS2018015.

[0011] Further, in the above application provided by the present invention, the Acer truncatum seeds are pretreated as follows before fermentation:

[0012] S1 Harvesting: Select healthy Acer truncatum seeds with wings that are tender green, plump, fresh, without pests, diseases or spoilage.

[0013] S2 Cleaning: Wash with clean water, drain, and spread out to dry.

[0014] S3 Blanching: Boil in water at 90 - 100 °C for 2 - 5 minutes, immediately immerse in cold water for cooling after blanching, and directly dry to a moisture content ≤ 8% after taking out.

[0015] S4 Crushing: Put the baked raw materials in a crusher and crush them into small pieces of 1 - 4 cm.

[0016] In the above application, the preparation method of the spore suspension of Eurotium cristatum NCPS2018015 is as follows:

[0017] Activated Eurotium cristatum NCPS2018015. Gently scrape the surface spores of the colony with a sterile inoculation loop into a conical flask containing sterile water and glass beads, shake on a shaker at 120 - 180 r / min for 20 - 40 min, count with a hemocytometer, and finally dilute to a concentration of 10 6 ~10 7 spores / mL of the Eurotium cristatum NCPS2018015 spore suspension.

[0018] Preferably, the shaking frequency of the shaker is 150 r / min, and the shaking time is 30 min.

[0019] Preferably, the concentration of the Eurotium cristatum NCPS2018015 spore suspension is 10 6 spores / mL.

[0020] In addition, the culture medium involved in the above application contains at least a glucose solution.

[0021] The preparation method of the culture medium is as follows: Add 40 - 60 mL of 4 - 6 wt% glucose solution to every 100 g of Acer truncatum seeds, mix and load into a cultivation bag, sterilize at 115 - 125 °C for 25 - 35 min, and then cool to room temperature to obtain the culture medium.

[0022] In the above application, when inoculating the Eurotium cristatum NCPS2018015 spore suspension, inoculate it into the culture medium at a ratio of 4 - 7 mL of spore suspension per 100 g of sterilized Acer truncatum seeds, and cultivate the inoculated cultivation bag at 28 - 30 °C for 7 - 10 days.

[0023] Furthermore, the tea beverage prepared by fermenting with Eurotium cristatum NCPS2018015 also falls within the scope of protection of the present invention.

[0024] Even further, a kind of tea bag prepared by fermenting with Eurotium cristatum NCPS2018015 provided by the present invention has the following steps:

[0025] (1) Pretreatment of Acer truncatum seeds: S1 Harvesting: Select healthy Acer truncatum seeds with wings that are tender green, thick, fresh, without pests, diseases and spoilage; S2 Cleaning: Wash with clean water, drain, and spread out to dry; S3 Blanching: Boil in water at 90 - 100 °C for 2 - 5 min, and immediately immerse in cold water for cooling after blanching; After blanching, directly bake to a moisture content ≤ 8%; S4 Crushing: Put the baked raw material into a crusher and crush it into small pieces with a diameter of 1 - 2 cm;

[0026] (2) Preparation of Eurotium cristatum NCPS2018015 spore suspension: Activate Eurotium cristatum NCPS2018015, gently scrape the spores on the surface of the colony with a sterile inoculation loop into a conical flask containing sterile water and glass beads, shake on a shaker at 120 - 180 r / min for 20 - 40 min, count with a hemocytometer, and finally dilute it into a Eurotium cristatum NCPS2018015 spore suspension with a concentration of 10 6 ~10 7 spores / mL;

[0027] (3) Fermentation of Acer truncatum seeds: According to the ratio of inoculating 4 - 7 mL of spore suspension per 100 g of sterilized Acer truncatum seeds, inoculate the Eurotium cristatum NCPS2018015 spore suspension prepared in (2) into the culture medium, and culture the inoculated culture bags at 28 - 30 °C for 7 - 10 days;

[0028] (4) Drying and packaging: Dry the Acer truncatum seed fermented tea obtained in (3) at 60 - 65 °C until the water content is 3 - 8%, obtain the fermented material, pack it into tea bags, and the mass of the tea bag is 6 - 8 g / bag.

[0029] In addition, the steps for preparing the pressed tea fermented by Eurotium cristatum NCPS2018015 provided by the present invention are as follows:

[0030] (1) Pretreatment of Acer truncatum seeds: S1 Harvesting: Select healthy Acer truncatum seeds with wings that are green, thick, fresh in color, free from pests, diseases and spoilage; S2 Cleaning: Wash with clean water, drain, and air-dry; S3 Blanching: Boil in water at 90 - 100 °C for 2 - 5 min, immediately immerse in cold water for cooling after blanching, and directly dry to a moisture content ≤ 8% after taking out; S4 Crushing: Place the baked raw material in a crusher and crush it into small pieces with a diameter of 3 - 4 cm;

[0031] (2) Preparation of Eurotium cristatum NCPS2018015 spore suspension: Activate Eurotium cristatum NCPS2018015, gently scrape the spores on the surface of the colony with a sterile inoculation loop into a conical flask containing sterile water and glass beads, shake on a shaker at 130 - 160 r / min for 25 - 35 min, count with a hemocytometer, and finally dilute it into a spore suspension of Eurotium cristatum NCPS2018015 with a concentration of 10 6 ~10 7 spores / mL;

[0032] (3) Fermentation of Acer truncatum seeds: According to the ratio of inoculating 3 - 5 mL of Eurotium cristatum NCPS2018015 spore suspension per 100 g of sterilized Acer truncatum seeds, inoculate the spore suspension prepared in (2) into the culture medium, and culture the inoculated culture bags at 28 - 30 °C for 5 - 8 days;

[0033] (4) Drying and packaging: The Acer truncatum seed fermented tea obtained in (3) is dried at 60 - 65 °C until the water content is 25 - 30%, obtaining a fermented material. The fermented material is placed in a mold and extruded to form a tea cake;

[0034] (5) The tea cake is dried at 60 - 65 °C until the water content is 3 - 8%.

[0035] The beneficial effects of the present invention are as follows:

[0036] (1) In the present invention, Eurotium cristatum NCPS2018015 is applied to the fermentation of Acer truncatum seeds, obtaining an Acer truncatum seed tea and developing a new use of Acer truncatum seeds as a tea product for daily drinking;

[0037] (2) After fermenting Acer truncatum seeds with Eurotium cristatum NCPS2018015 of the present invention, the contents of bioactive components contained in Acer truncatum seeds are all improved. For example, the plant soluble sugar in the unfermented Acer truncatum seed raw material is only 15.09 mg / g, and the plant soluble sugar in the fermented Acer truncatum seed tea is 24.67 mg / g, with the content of plant soluble polysaccharide increased by 63.49% compared with that in the unfermented Acer truncatum seed raw material;

[0038] Moreover, flavonoid components were not detected in the unfermented Acer truncatum seeds, but flavonoid components were detected in the fermented tea obtained after fermentation. The highest content of flavonoids is 1.293 mg / g. At the same time, the total antioxidant capacity, DPPH free radical scavenging rate, and ABTS free radical scavenging rate of the fermented Acer truncatum seed tea drink are all higher than those of the unfermented Acer truncatum seeds, and the health care effect of the tea drink is good;

[0039] (3) In the present invention, through pre - treatments such as blanching of Acer truncatum seeds and further fermenting Acer truncatum seeds with Eurotium cristatum NCPS2018015, it is beneficial to remove the original grassy and bitter taste in the Acer truncatum seed raw material. The obtained tea drink has a bright appearance color, showing a yellow - brown color after brewing, with a mellow taste and no bitter grassy taste. Description of the Drawings

[0040] Figure 1 It is the strain diagram of Eurotium cristatum NCPS2018015 used in Example 1 of the present invention; among them, Figure A is the slant morphology diagram of the strain, and Figure B is the colony morphology diagram after culturing for 8 days;

[0041] Figure 2 It is the Acer truncatum seed tea fermented with Eurotium cristatum NCPS2018015 in Example 1 of the present invention; Figures A and B are pictures after culturing for 7 days; Figures C and D are pictures before and after drying the fermented tea respectively;

[0042] Figure 3 This is a picture of the finished product of Acer truncatum seed tea prepared by fermenting Eurotium cristatum NCPS2018015 in Example 1 of the present invention, including the teabag (a) and the tea soup (b). Detailed implementation manners

[0043] To enable those skilled in the art to better understand the present invention, the present invention will be further elaborated below in conjunction with specific implementation manners.

[0044] Example 1

[0045] The steps for preparing the teabag fermented by Eurotium cristatum NCPS2018015 are as follows:

[0046] (1) Pretreatment of Acer truncatum seeds: S1 Harvesting: Select healthy Acer truncatum seeds with wings that are tender green in color, thick, fresh, free from pests, diseases and spoilage; S2 Cleaning: Wash with clean water, drain, and spread out to dry; S3 Blanching: Boil in water at 95°C for 2 min, immediately immerse in cold water for cooling after blanching, and bake until the moisture content is 8%; S4 Crushing: Place the baked raw materials in a crusher and crush them into small pieces with a particle size of 1.5 - 2 cm in length;

[0047] (2) Preparation of Eurotium cristatum NCPS2018015 spore suspension: Activate Eurotium cristatum NCPS2018015, gently scrape the spores on the surface of the colony with a sterile inoculation loop into a conical flask containing 100 mL of sterile water and glass beads, shake on a shaker at 150 r / min for 30 min, count with a hemocytometer, and finally dilute it into a Eurotium cristatum NCPS2018015 spore suspension with a concentration of 10 6 spores / mL;

[0048] (3) Fermentation of Acer truncatum seeds: According to the ratio of inoculating 6 mL of Eurotium cristatum NCPS2018015 spore suspension per 100 g of sterilized Acer truncatum seeds, inoculate the spore suspension prepared in (2) into the culture medium, and culture the inoculated culture bags at 30°C for 8 days;

[0049] (4) Drying and packaging: Dry the Acer truncatum seed fermentation broth obtained in (3) at 60°C until the water content is 8% to obtain the fermented material, and pack it into teabags, with the mass of each teabag being 6 g / bag.

[0050] The slant morphology diagram of the strain of Eurotium cristatum NCPS2018015 used in this example after special screening and preservation is as shown in Figure A of the appendix Figure 1 and the colony morphology diagram after culturing for 7 - 8 days is as shown in Figure B of the appendix Figure 1 . It can be seen from the figure that the color of Eurotium cristatum NCPS2018015 in the present invention is bright yellow and golden yellow.

[0051] The fermentation of Acer truncatum seeds by using Eurotium cristatum NCPS2018015 of the present invention is shown in the attached figure. Figure 2 As shown in Figures A to D, Figures A and B are pictures of tea drinks that have been fermented and cultured for 7 days, and Figures C and D are pictures of the fermented tea before and after drying, respectively.

[0052] It can be clearly seen from Figures B to D that a large number of golden colonies are attached to the outer surface of the Acer truncatum seeds, indicating that the Eurycoma cristatum NCPS2018015 can ferment well with the Acer truncatum seeds as substrate, which is beneficial to improve the beneficial active ingredients in the Acer truncatum seeds. The prepared tea beverage also contains a large amount of Eurycoma longifolia.

[0053] Further, the tea bag prepared in this embodiment is as follows Figure 3 As shown in Figure a, the color after brewing is as shown in the attached Figure 3 As shown in Figure b.

[0054] It can be seen that the prepared Acer truncatum seed tea has an orange-yellow to yellowish-brown color after brewing, with no residue particles floating, and the obtained fermented tea has a strong tea aroma, no grassy smell, and is slightly bitter at first with a sweet aftertaste.

[0055] Example 2

[0056] The cake tea is prepared by fermenting Eurotium cristatum NCPS2018015, and the steps are as follows:

[0057] (1) Pretreatment of Acer truncatum seeds: Select healthy, pest-free, and non-deteriorated Acer truncatum seeds with tender green color, fleshy, and fresh wings, wash with clean water, drain, and air-dry, and then blanch in 98° C. water for 3 min, immediately soak in cold water to cool after blanching, take out and bake to a moisture content of 6%, and finally put the baked raw materials into a crusher to crush into small pieces with a diameter of about 3 cm and a length;

[0058] (2) Preparation of spore suspension of Eurotium cristatum NCPS2018015: Activate Eurotium cristatum, gently scrape spores from the surface of the colony with a sterile inoculation loop and place in a conical flask containing 100 mL of sterile water and glass beads, shake on a shaker at 160 rpm for 35 min, count on a hemocytometer, and finally dilute to a concentration of 10 7 Spore suspension of Eurotium cristatum NCPS2018015 at 100 / mL;

[0059] (3) Fermenting Acer truncatum seeds: inoculate the spore suspension prepared in (2) into the culture medium at a ratio of 5 mL of the spore suspension of Eurotium cristatum NCPS2018015 per 100 g of sterilized Acer truncatum seeds, and culture the inoculated culture bag at 30° C. for 5 days;

[0060] (4) Drying and packaging: The Acer truncatum seed fermentation broth obtained in (3) is dried at 60 - 65 °C until the water content is 25% to obtain the fermented material. The fermented material is placed in a mold and extruded to form a tea cake.

[0061] (5) The tea cake is dried at 65 °C until the water content is 5%.

[0062] Examples 3 - 5

[0063] On the basis of Example 1, the inoculation ratio of Eurotium cristatum NCPS2018015 spore suspension in Acer truncatum seeds, the concentration of Eurotium cristatum NCPS2018015 spore suspension, and the fermentation time are adjusted. The specific parameters of each example are shown in Table 1.

[0064] Table 1 Partial parameter settings in Examples 3 - 5

[0065]

[0066]

[0067] Example 6

[0068] The contents of active ingredients in the Acer truncatum seed tea prepared in Examples 1 - 5 are detected. The detection methods are as follows:

[0069] For the determination of flavonoids, the Solarbio plant flavonoid content detection kit is selected.

[0070] For the determination of total antioxidant capacity, the Solarbio total antioxidant capacity (T - AOC) detection kit is selected.

[0071] For the determination of DPPH free radical scavenging ability, the Solarbio DPPH free radical scavenging ability detection kit is selected.

[0072] For the determination of ABTS free radical scavenging ability, the Solarbio ABTS free radical scavenging ability detection kit is selected.

[0073] For the determination of polysaccharide content, the Solarbio plant soluble sugar content detection kit is selected.

[0074] In Examples 1 - 5, during the fermentation of Acer truncatum seeds with Eurotium cristatum NCPS2018015, the content of each component is as shown in Table 2 below.

[0075] Table 2 Contents of each component in Acer truncatum seed tea under different fermentation conditions

[0076] Example 1 Example 2 Example 3 Example 4 Example 5 Unfermented Plant soluble sugar (mg / g) 23.58 20.72 20.39 22.89 24.67 15.09 Flavonoid (mg / g) 1.234 1.086 1.154 1.265 1.293 / Total antioxidant (umol / g) 23.59 20.32 21.36 23.61 23.83 22.71 DPPH (%) 43.85 40.67 41.59 44.13 43.77 41.57 ABTS (%) 78.76 74.41 75.17 77.75 79.21 69.44

[0077] It can be seen from the data in Table 2 that:

[0078] First, in the unfermented Acer truncatum seeds, the content of plant soluble sugar is relatively low, only 15.09 mg / g. After fermentation with Eurotium cristatum NCPS2018015, the content of plant soluble sugar in the Acer truncatum seed tea obtained in each example showed a significant increase. The content of plant soluble sugar in the Acer truncatum seed tea in Example 5 was the highest, 24.67 mg / g, which was a 63.49% increase compared to the content of plant soluble sugar in the unfermented Acer truncatum seed raw material.

[0079] In fact, the soluble sugar in tea products is the main flavor substance of the tea soup, which can give the tea soup a sweet and mellow taste when consumed. Moreover, during the processing of tea, the soluble sugar undergoes the Maillard reaction with amino acids or proteins, generating furfural derivatives and important aroma substances such as pyrroles and pyrazines, increasing the fragrance of the tea drink. In addition, as an important primary metabolite of tea plants, soluble sugar is not only the main precursor of secondary metabolites of tea plants, but also can participate in regulating multiple life activities of tea plants as a signaling molecule, such as stress response, pathogen defense, reactive oxygen species scavenging, etc. Therefore, the content of soluble sugar in tea directly affects the quality of tea.

[0080] Second, the presence of flavonoids was not detected in the unfermented Acer truncatum seeds, while after fermentation with Eurotium cristatum NCPS2018015, flavonoid components were detected in the obtained Acer truncatum seed tea, and the highest content of flavonoid components reached 1.293 mg / g. In addition, the total antioxidant capacity, DPPH free radical scavenging rate, and ABTS free radical scavenging rate of the fermented Acer truncatum seed tea were higher than those of the unfermented Acer truncatum seeds. This may be because Eurotium cristatum can utilize the nutrients in Acer truncatum seeds for its own metabolism during fermentation. While meeting its own nutritional needs, it will also produce extracellular enzymes such as polyphenol oxidase, pectinase, protease, and cellulase, and the production of these extracellular enzymes can in turn act on the Acer truncatum seed raw material, catalyzing the degradation and transformation of macromolecular substances in Acer truncatum seeds into small molecular components.

[0081] It can be seen that the content of active ingredients in the tea drink obtained by fermenting Acer truncatum seeds with Eurotium cristatum NCPS2018015 in the present invention has been significantly improved, and this strain has good stability.

[0082] Comparative Example 1

[0083] Fermentation was carried out using a commercially available Jinhuajun strain, and the remaining operations were the same as in Example 1.

[0084] Comparative Example 2

[0085] Different from Example 1, in step (1), the Acer truncatum seeds were not subjected to scalding treatment.

[0086] Comparative Example 3

[0087] Different from Example 1, in (1), the Acer truncatum seeds are not pretreated, and the whole Acer truncatum seeds are directly used as the raw material for fermentation.

[0088] Comparative Example 4

[0089] Different from Example 2, in step (3), 15 mL of Eurotium cristatum spore suspension is inoculated into every 100 g of sterilized Acer truncatum seeds.

[0090] Comparative Example 5

[0091] Different from Example 1, in step (3), 2 mL of Eurotium cristatum spore suspension is inoculated into every 100 g of sterilized Acer truncatum seeds.

[0092] The appearance and sensory properties of the Acer truncatum seed tea prepared in Example 1 and Comparative Examples 1-5 were evaluated, and the sensory evaluation form is shown in Table 3.

[0093] Table 3 Sensory evaluation of the Acer truncatum seed tea brewed and tasted with different treatment processes

[0094]

[0095] As can be seen from Table 3 above:

[0096] In Example 1, after fermenting the Acer truncatum seeds with Eurotium cristatum NCPS2018015, the obtained tea drink has a strong tea flavor, tastes bitter at the entrance with a sweet aftertaste, and has no grassy smell and no astringency when entering the mouth. The color of the tea drink is also relatively bright.

[0097] In Comparative Example 1, the Acer truncatum seeds were fermented with commercially available JinHua fungus, and the obtained Acer truncatum seed tea has a faint grassy taste. After brewing the tea drink, it presents a grayish-brown color, and the amount of JinHua fungus is small. This may be because the commercially available JinHua fungus is difficult to directly use the Acer truncatum seeds with a high oil content but low available sugar and protein content as a substrate for fermentation, and the fermentation is not sufficient, so the fermentation effect is poor. However, the screened Eurotium cristatum NCPS2018015 in the present invention can better utilize the components in the Acer truncatum seeds for fermentation. After fermentation, not only the content of active components such as plant soluble sugar and flavonoids in the Acer truncatum seed tea is increased, but also the amount of the strain has increased significantly, and the fragrance of the obtained fermented tea drink has been significantly improved.

[0098] In Comparative Examples 2 to 3, since the pretreatment of Acer truncatum seeds was not as sufficient as that in Example 1, the Acer truncatum seeds in Comparative Example 2 were not subjected to blanching treatment, and the Acer truncatum seeds in Comparative Example 3 were not subjected to any pretreatment. The fermented tea beverages obtained from both groups of experiments had a relatively strong grassy flavor, indicating that the grassy flavor of Acer truncatum seeds could not be removed only through fermentation. The blanching treatment played a crucial role in the taste of Acer truncatum seed tea. In addition, the bitter taste of the Acer truncatum seed tea obtained by directly fermenting without sufficient pretreatment was also relatively strong, indicating that the pretreatment of Acer truncatum seeds could greatly improve the taste of the fermented tea beverage.

[0099] In Comparative Examples 4 to 5, the inoculum size of the strain during the fermentation of Eurotium cristatum NCPS2018015 was adjusted respectively. Among them, the tea beverage obtained after fermentation in Comparative Example 4 contained a large amount of Eurotium cristatum, but the tea beverage showed a dark brown state, and the color acceptability was poor. In Comparative Example 5, the amount of Eurotium cristatum was extremely small and the color was bright, but due to the too low content of Eurotium cristatum, the fermentation was not sufficient and the content of active ingredients in the tea beverage was low.

[0100] In summary, compared with the Acer truncatum seed tea fermented by commercially available strains and under extreme fermentation conditions, the Acer truncatum seed tea fermented by the specifically screened Eurotium cristatum NCPS2018015 strain of the present invention has a higher content of active ingredients in the tea beverage product and a better sensory experience.

Claims

1. Application of Eurotium cristatum NCPS2018015 in the fermentation for preparing tea beverages, characterized in that, After activating Eurotium cristatum NCPS2018015, a spore suspension is prepared and inoculated into the culture medium containing Acer truncatum seeds, followed by fermentation culture to obtain Acer truncatum seed tea; the Eurotium cristatum was deposited at the China Center for Type Culture Collection on December 12, 2018, with the deposit number: CCTCC NO: M 2018882, and the taxonomic name is: Eurotium cristatum Eurotium cristatum NCPS2018015; The preparation method of the Eurotium cristatum NCPS2018015 spore suspension is as follows: Activated Eurotium cristatum NCPS2018015. Gently scrape the surface spores of the colony with a sterile inoculation loop into a conical flask containing 100 mL of sterile water and glass beads, shake on a shaker at 150 r / min for 30 min, count with a hemocytometer, and finally dilute to a concentration of 10 6 spore suspension of Eurotium cristatum NCPS2018015 with a density of cells / mL; The Acer truncatum seeds have been pretreated as follows: S1 Harvesting: Select healthy Acer truncatum seeds with wings that are tender green in color, thick, fresh, without pests, diseases, or spoilage; S2 Cleaning: Wash with clean water, drain, and air-dry; S3 Blanching: Boil in water at 95°C for 2 min, immediately immerse in cold water for cooling after blanching, and bake until the moisture content is 8%; S4 Crushing: Place the baked raw material in a crusher and crush it into small pieces with a particle size of 1.5 - 2 cm in length; The culture medium contains at least a glucose solution; the preparation method of the culture medium is: Add 40 - 60 mL of 4 - 6 wt% glucose solution to every 100 g of Acer truncatum seeds, mix them and then pack them into culture bags, sterilize at 115 - 125°C for 25 - 35 min, and then cool to room temperature to obtain the culture medium; The fermentation method of the Acer truncatum seeds is as follows: According to the ratio of inoculating 6 mL of Eurotium cristatum NCPS2018015 spore suspension per 100 g of sterilized Acer truncatum seeds, inoculate the prepared spore suspension into the culture medium, and culture the inoculated culture bags at 30°C for 8 days.

2. The steps for preparing a teabag fermented by Eurotium cristatum NCPS2018015 are as follows: (1) Acer truncatum seed pretreatment: S1 Harvesting: Select healthy Acer truncatum seeds with wings that are tender green in color, thick, fresh, without pests, diseases, or spoilage; S2 Cleaning: Wash with clean water, drain, and air-dry; S3 Blanching: Boil in water at 90 - 100°C for 2 - 5 min, immediately immerse in cold water for cooling after blanching, and bake until the moisture content ≤ 8%; S4 Crushing: Place the baked raw material in a pulverizer and crush it into small pieces of 1 - 2 cm; (2) Preparation of Eurotium cristatum NCPS2018015 spore suspension: Activate Eurotium cristatum NCPS2018015, gently scrape the spores on the surface of the colony with a sterile inoculation loop into a conical flask containing sterile water and glass beads, shake on a shaker at 120 - 180 r / min for 20 - 40 min, count with a hemocytometer, and finally dilute it into a Eurotium cristatum NCPS2018015 spore suspension with a concentration of 10 6 ~10 7 spores / mL; (3) Fermenting Acer truncatum seeds: According to the ratio of inoculating 4 - 7 mL of Eurotium cristatum NCPS2018015 spore suspension per 100 g of sterilized Acer truncatum seeds, inoculate the Eurotium cristatum NCPS2018015 spore suspension prepared in (2) into the culture medium, and culture the inoculated culture bags at 28 - 30°C for 7 - 10 days; (4) Drying and packaging: Dry the Acer truncatum seed fermented tea obtained in (3) at 60 - 65°C until the water content is 3 - 8% to obtain the fermented material, pack it into bags to make teabags, and the mass of the teabags is 6 - 8 g / bag.

3. The steps for preparing a compressed tea fermented by Eurotium cristatum NCPS2018015 are as follows: (1) Acer truncatum seed pretreatment: S1 Harvesting: Select healthy Acer truncatum seeds with wings that are tender green in color, thick, fresh, without pests, diseases, or spoilage; S2 Cleaning: Wash with clean water, drain, and air-dry; S3 Blanching: Boil in water at 90 - 100°C for 2 - 5 min, immediately immerse in cold water for cooling after blanching, and bake until the moisture content ≤ 8%; S4 Crushing: Place the baked raw material in a crusher and crush it into small pieces with a diameter of 3 - 4 cm in length; (2) Preparation of Eurotium cristatum NCPS2018015 spore suspension: Activate Eurotium cristatum NCPS2018015, gently scrape the spores on the colony surface with a sterile inoculation loop into a conical flask containing sterile water and glass beads, shake on a shaker at 130 - 160 r / min for 25 - 35 min, count with a hemocytometer, and finally dilute to a spore suspension of Eurotium cristatum NCPS2018015 with a concentration of 10 6 ~10 7 spores / mL; (3)Ferment Acer truncatum seeds: According to the proportion of inoculating 3 - 5 mL of the spore suspension of Eurotium cristatum NCPS2018015 per 100 g of sterilized Acer truncatum seeds, inoculate the spore suspension of Eurotium cristatum NCPS2018015 prepared in (2) into the culture medium, and incubate the inoculated culture bags at 28 - 30 °C for 5 - 8 days; (4)Dry and package: Dry the Acer truncatum seed fermented tea obtained in (3) at 60 - 65 °C until the water content is 25 - 30% to obtain the fermented material, and place the fermented material in a mold for extrusion to make tea cakes; (5)Dry the tea cakes at 60 - 65 °C until the water content is 3 - 8%.

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