Mulberry leaf tea drink and preparation method thereof

Abstract

The invention discloses a mulberry leaf tea beverage and a preparation method thereof, and aims to solve the problems of heavy odor, low functional component and insufficient extraction rate of existing mulberry leaf tea leaves. According to the technical scheme, the method comprises the following steps: 1, cleaning and dehydrating fresh tender mulberry leaves and mulberry buds, spreading and withering; 2, piling and fermenting the withered raw materials; 3, steaming the piled raw materials; 4, mixing the steaming raw materials with the semen cassiae raw powder in proportion; 5, inoculating eurotium cristatum, pressing into cakes, and fermenting; and 6, drying the fermentation product, performing microwave-assisted extraction, and blending, sterilizing and filling extract liquor. According to the invention, eurotium cristatum is fermented and compounded with semen cassiae, so that green odor is effectively removed, and the inhibition rate of alpha-glucosidase is increased so as to strengthen the effect of reducing blood sugar; the extraction rate of functional components is improved through microwave-assisted extraction. The product has good flavor and strong efficacy, is suitable for people with health maintenance and blood sugar management, and has high practical value.

Description

Technical Field

[0001] This invention relates to the field of tea beverage preparation technology, specifically to a mulberry leaf tea beverage and its preparation method. Background Technology

[0002] Mulberry leaves are a food and medicine of the same origin, rich in bioactive components. They can be made into dried tea for brewing. The Compendium of Materia Medica calls them "the herb of immortals". They have the effects of eliminating sores and blemishes, losing weight and reducing fat, and lowering blood viscosity. They are suitable for the adjunctive treatment of diabetic patients and for general health maintenance.

[0003] In recent years, probiotic fermentation technology has been widely used in tea processing. It can improve the taste and enhance the aroma by converting phenolic substances through metabolic enzymes. As a dominant probiotic in Fu brick tea, *Aspergillus cristatus* can secrete amylase, polyphenol oxidase, etc., to promote the conversion of components. Its effects on reducing fat and lowering blood sugar have attracted much attention.

[0004] However, existing mulberry leaf tea has obvious shortcomings: First, the resources are not fully utilized, and most of the products on the market are primary agricultural products, lacking deep processing and high-value development, making it difficult to guarantee the efficacy of the ingredients; second, there are flavor defects, as mulberry leaf tea has a strong grassy odor, which existing fermentation processes cannot effectively improve, and the use of food additives to enhance the flavor can easily raise health concerns; third, the efficacy is limited, as ordinary mulberry leaf tea has low levels of blood sugar-lowering functional components, which cannot meet consumer demand. Summary of the Invention

[0005] Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a mulberry leaf tea beverage and its preparation method, thus solving the technical problems mentioned in the background section.

[0006] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: a method for preparing mulberry leaf tea, comprising the following steps: 1. Take tender mulberry leaves and buds picked on the same day, rinse them with clean water, spin dry, spread the dehydrated raw materials evenly in a withering trough, blow cold air until the surface moisture is dried, and then intermittently blow air to wither until the moisture content is 55%-62%, with a total withering time of 12-18 hours; 2. Pile the withered mulberry leaves for fermentation at a temperature of 25-40℃ and a relative humidity of 80-90%. 1. Ferment for 10-12 hours under the following conditions; 2. Steam the fermented raw materials at 100-110℃ for 4-8 minutes; 3. Take 80-100 parts by weight of the raw materials treated in step 3, and mix them with 20-30 parts of cassia seed powder; 4. Inoculate the mixed raw materials from step 4 with *Aspergillus cristatus* and press them into tea cakes; 5. Place the tea cakes in a fermentation room, control the temperature at 30-35℃ and the humidity at 80-90%, and ferment for 6-14 days.

[0007] Preferably, when the temperature is low in step 1, intermittent blowing can use hot air to accelerate withering.

[0008] Preferably, the temperature of composting in step 2 is 30°C, the relative humidity is 85%, and the fermentation time is 10 hours.

[0009] Preferably, in step 3, the steaming temperature is preferably 105℃ and the steaming time is preferably 6 minutes.

[0010] Preferably, the ratio of the mixed raw materials in step 4 is 80 parts mulberry leaf raw material and 20 parts cassia seed powder.

[0011] Preferably, in step 6, the fermentation temperature is preferably 30°C, the humidity is preferably 80%, and the fermentation time is preferably 8 days.

[0012] Preferably, the process further includes step 7: drying the fermented tea cake at 60°C until the moisture content is below 6%, and then storing it at room temperature for 2 weeks.

[0013] Preferably, the process further includes step 8: extracting the tea cake after it has been placed, with an extraction temperature of 95°C, a time of 10-20 minutes, a tea-to-water ratio of 1:40, and using a 300-400W microwave-assisted extraction.

[0014] Preferably, the process further includes step 9: diluting the extract by 4 times, adding vitamin C and sodium bicarbonate, sterilizing at 136°C for 15 seconds using UHT, cooling to 20°C, and then aseptically cold-filling to obtain the finished product.

[0015] (III) Beneficial Effects Compared with existing technologies, this invention provides a mulberry leaf tea beverage and its preparation method, which has the following beneficial effects: Improved flavor and taste: Through a dual fermentation process of "pile fermentation + secondary fermentation by *Aspergillus cristatus*", combined with the addition of cassia seeds, the grassy odor substances in mulberry leaves can be effectively degraded, giving the beverage a unique mellow aroma and solving the problem of low consumer acceptance of traditional mulberry leaf tea. Sensory evaluation shows that the flavor is significantly superior to traditional products; Enhanced hypoglycemic effect: *Aspergillus cristatus* fermentation can promote the conversion of active ingredients in mulberry leaves. Combined with the synergistic effect of cassia seeds, it significantly improves the α-glucosidase inhibition rate of the product, enhances the hypoglycemic effect, and is more suitable for patients with impaired glucose tolerance and diabetes. Meeting the needs of diabetic patients; improving extraction efficiency: using 300-400W microwave-assisted extraction, combined with optimized parameters of 95℃ and a tea-to-water ratio of 1:40, can accelerate the dissolution of functional components, resulting in a higher extraction rate compared to traditional extraction methods, fully leveraging the efficacy value of raw materials; achieving high-value utilization of raw materials: through deep processing technology, primary mulberry leaf raw materials are transformed into high-efficacy beverages, reducing resource waste, increasing the added value of agricultural products, and having good economic and social benefits; ensuring drinking safety: no food additives are used throughout the process, only natural fermentation and raw material compounding are used to improve flavor, combined with UHT aseptic sterilization technology, balancing flavor and safety, and better meeting the needs of healthy consumers. Detailed Implementation

[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] A method for preparing mulberry leaf tea includes the following steps: 1. Take freshly picked mulberry leaves and buds, rinse them with clean water, spin dry, spread the dehydrated raw materials evenly in a withering trough, blow cold air until the surface moisture is dry, then intermittently blow air to wither until the moisture content is 55%-62%, with a total withering time of 12-18 hours; 2. Pile the withered mulberry leaves and ferment them at a temperature of 25-40℃ and a relative humidity of 80-90% for 10-12 hours; 3. Steam the fermented raw materials at a temperature of 100-110℃ for 4-8 minutes; 4. Take 80-100 parts by weight of the raw materials processed in step 3, mix them with 20-30 parts by weight of cassia seed powder, and mix evenly; 5. Inoculate the mixed raw materials from step 4 with *Aspergillus cristatus*, and press them into tea cakes; 6.The tea cake is placed in a fermentation chamber, with the temperature controlled at 30-35℃ and humidity at 80-90%, for 6-14 days. In step 1, when the temperature is low, intermittent blowing can be used with hot air to accelerate withering. In step 2, the preferred temperature for pile fermentation is 30℃, the preferred relative humidity is 85%, and the preferred fermentation time is 10 hours. In step 3, the preferred steaming temperature is 105℃, and the preferred steaming time is 6 minutes. In step 4, the ratio of the mixed raw materials is 80 parts mulberry leaf raw material and 20 parts cassia seed powder. In step 6, the preferred fermentation temperature is 30℃, the preferred humidity is 80%, and the preferred fermentation time is... The process includes step 7: drying the fermented tea cake at 60℃ until the moisture content is below 6%, and then storing it at room temperature for 2 weeks. Step 8: extracting the stored tea cake at 95℃ for 10-20 minutes with a tea-to-water ratio of 1:40, using a 300-400W microwave-assisted extraction. Step 9: diluting the extract 4 times, adding vitamin C and sodium bicarbonate, sterilizing at 136℃ for 15 seconds using UHT, then cooling to 20℃, and aseptically cold-filling to obtain the finished product. This is a mulberry leaf tea beverage and its preparation method, possessing the following characteristics: Benefits: Improved flavor and taste: Through a dual fermentation process of "pile fermentation + secondary fermentation with *Aspergillus cristatus*", combined with cassia seed, the grassy odor substances in mulberry leaves can be effectively degraded, giving the beverage a unique and mellow aroma, solving the problem of low consumer acceptance of traditional mulberry leaf tea. Sensory evaluation shows that the flavor is significantly superior to traditional products; Enhanced blood sugar lowering effect: *Aspergillus cristatus* fermentation can promote the conversion of active ingredients in mulberry leaves. Combined with the synergistic effect of cassia seed, it significantly improves the α-glucosidase inhibition rate of the product, enhances the blood sugar lowering effect, and is more suitable for the needs of people with impaired glucose tolerance and diabetes; Improved extraction efficiency: Microwave-assisted extraction (300-400W) combined with optimized parameters of 95℃ and a tea-to-water ratio of 1:40 accelerates the dissolution of functional components, resulting in a higher extraction rate compared to traditional extraction methods and fully realizing the efficacy of the raw materials. This also achieves high-value utilization of the raw materials: through deep processing, primary mulberry leaf raw materials are transformed into high-efficacy beverages, reducing resource waste, increasing the added value of agricultural products, and yielding significant economic and social benefits. Furthermore, it ensures drinking safety: no food additives are used throughout the process; flavor is improved solely through natural fermentation and ingredient blending, coupled with UHT aseptic sterilization, balancing flavor and safety to better meet the demands of health-conscious consumers.

[0018] An example of a mulberry leaf tea beverage and its preparation method: Example 1 Raw material pretreatment: Take tender mulberry leaves and buds picked on the same day, rinse them with clean water to remove impurities, and then dehydrate them simply by using a centrifuge. Spread the dehydrated raw materials evenly in the withering trough.

[0019] Withering treatment: The above raw materials are treated with cold air until the surface moisture is completely dried; then intermittent blowing is carried out. If the temperature is low during production, hot air can be blown in appropriately. Withering is stopped when the moisture content of mulberry leaves drops to 55%. The entire withering process takes 12 hours.

[0020] Pile fermentation: The withered mulberry leaves are piled up and fermented for 10 hours at a temperature of 30℃ and a relative humidity of 85%.

[0021] Steam treatment: The raw materials after composting and fermentation are steamed at a controlled temperature of 105℃ for 6 minutes.

[0022] Raw material mixing and inoculation: Take 80 parts by weight of steamed mulberry leaf raw material, mix with 20 parts of cassia seed powder, mix evenly and inoculate with Eurotium cristatum, and press the mixed raw material into tea cake.

[0023] Secondary fermentation: Place the tea cake in a fermentation room, control the temperature at 30℃ and the humidity at 80%, and ferment for 8 days.

[0024] Drying and aging: Dry the fermented tea cake at 60℃ until the moisture content is below 6%, and then let the dried mulberry leaf tea sit at room temperature for 2 weeks.

[0025] Microwave-assisted extraction: Aged mulberry leaf tea was extracted at a controlled temperature of 95℃ for 10 minutes with a tea-to-water ratio of 1:40. A 300W microwave-assisted extraction was used.

[0026] Preparation and bottling: Dilute the extract 4 times, add vitamin C and sodium bicarbonate and mix well. After sterilization at 136℃ for 15s by UHT, cool to 20℃ and aseptically cold fill to obtain mulberry leaf tea beverage.

[0027] Example 2 Raw material pretreatment: Take tender mulberry leaves and buds picked on the same day, rinse them with clean water and dehydrate them with a spin dryer, and spread the dehydrated raw materials evenly in the withering tank.

[0028] Withering process: First, blow cold air to dry the surface moisture, then blow air intermittently (add hot air when the temperature is low) until the moisture content of the mulberry leaves reaches 60%, and stop when the total withering time is 16 hours.

[0029] Pile fermentation: After wilting, the mulberry leaves are piled up and fermented for 12 hours at a temperature of 40℃ and a relative humidity of 90%.

[0030] Steam treatment: The raw materials after composting are steamed at 110℃ for 8 minutes.

[0031] Raw material mixing and inoculation: Take 90 parts by weight of steamed mulberry leaf raw material, mix with 30 parts of cassia seed powder, mix evenly, inoculate with Eurotium cristatum, and press into tea cakes.

[0032] Secondary fermentation: Place the tea cake in a fermentation room, control the temperature at 35℃ and the humidity at 90%, and ferment for 12 days.

[0033] Drying and aging: The fermented tea cakes are dried at 60℃ until the moisture content is below 6%, and then left at room temperature for 2 weeks.

[0034] Microwave-assisted extraction: Aged mulberry leaf tea was extracted at 95℃ for 20 minutes with a tea-to-water ratio of 1:40 using a 400W microwave-assisted extraction.

[0035] Preparation and filling: The extract is diluted 4 times, vitamin C and sodium bicarbonate are added and mixed, sterilized by UHT (136℃, 15s), cooled to 20℃, and aseptically cold-filled to obtain the finished product.

[0036] Comparative Example 1 (Preparation of Traditional Mulberry Leaf Tea Beverage) Traditional tea making: Tender mulberry leaves and buds picked that day are selected, washed, cut, withered, rolled, and dried to make traditional mulberry leaf tea.

[0037] Extraction process: The above-mentioned traditional mulberry leaf tea was extracted at a temperature of 95℃ for 10 minutes with a tea-to-water ratio of 1:40 using a 300W microwave-assisted extraction.

[0038] Blending and bottling: The extract is diluted 4 times, vitamin C and sodium bicarbonate are added, and the mixture is sterilized by UHT (136℃, 15s) and then cooled to 20℃ for aseptic cold filling to obtain mulberry leaf tea beverage.

[0039] Comparative Example 2 (Preparation without microwave-assisted extraction) Raw material pretreatment: Take tender mulberry leaves and buds picked on the same day, rinse them with clean water, spin dry and dehydrate them, and spread them evenly in the withering trough.

[0040] Withering treatment: Dry the surface moisture with cold air, and then wither with intermittently with air until the moisture content is 55%, for a total of 12 hours (hot air is added when the temperature is low).

[0041] Composting: After withering, mulberry leaves are composted for 10 hours at 30℃ and 85% relative humidity.

[0042] Steam treatment: Steam at 105℃ for 6 minutes.

[0043] Raw material mixing and inoculation: 80 parts of steamed mulberry leaf raw material were mixed with 20 parts of cassia seed powder, inoculated with Eurotium cristatum, and then pressed into tea cakes.

[0044] Secondary fermentation: Ferment for 8 days at 30℃ and 80% humidity.

[0045] Drying and aging: Dry at 60℃ until the moisture content is below 6%, and then leave at room temperature for 2 weeks.

[0046] Conventional extraction: Aged mulberry leaf tea was used for extraction at 95℃ for 10 minutes, with a tea-to-water ratio of 1:40. Microwave-assisted extraction was not used.

[0047] Preparation and filling: The extract is diluted 4 times, vitamin C and sodium bicarbonate are added, and the mixture is sterilized by UHT and then aseptically cold-filled to obtain the finished product.

[0048] Implementation Results Description Sensory evaluation: A sensory evaluation panel of 20 people evaluated the aroma, taste and color of the beverages of Examples 1 and 2 and Comparative Examples 1 and 2 (out of 10). The results showed that the sensory scores of Examples 1 and 2 were significantly higher than those of Comparative Examples 1 and 2, indicating that the process of the present invention can effectively improve the grassy smell of mulberry leaf tea and enhance its flavor and taste.

[0049] Hypoglycemic efficacy test: The α-glucosidase inhibition rate of the above samples was detected. The inhibition rates of Examples 1 and 2 were significantly higher than those of Comparative Examples 1 and 2, confirming that the present invention can significantly enhance the hypoglycemic efficacy by combining *Aspergillus cristatus* fermentation with cassia seed.

[0050] Extraction efficiency comparison: Compared with Comparative Example 2, Example 1 showed a higher extraction rate of functional components due to the use of microwave-assisted extraction, and the efficacy of the raw materials was fully realized.

[0051] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a mulberry leaf tea beverage, characterized by, The method comprises the following steps:

1. Take the fresh mulberry leaves and mulberry buds picked on the same day, rinse them with clean water, and then dry them. Spread the dried raw materials evenly in a wilting tank, and blow cold air until the surface moisture is blown dry. Then, intermittently blow air to wilt the materials to a moisture content of 55-62%, and the total wilting time is 12-18 hours; 2. Ferment the wilted mulberry leaves under the conditions of a temperature of 25-40℃ and a relative humidity of 80-90% for 10-12 hours; 3. Steam the fermented raw materials at a temperature of 100-110℃ for 4-8 minutes; 4. Take 80-100 parts of the raw materials treated in step 3, and mix them with 20-30 parts of raw cassia seed powder by weight; 5. Inoculate Eurotium cristatum into the mixed raw materials in step 4, and press them into tea cakes; 6. Place the tea cakes in a fermentation chamber, and control the temperature at 30-35℃ and the humidity at 80-90% for fermentation for 6-14 days.

2. A mulberry leaf tea beverage and a method of preparing the same according to claim 1, characterized in that, When the air temperature in step 1 is low, intermittent blowing of hot air can be used to accelerate wilting.

3. A mulberry leaf tea beverage and a method of preparing the same according to claim 1, characterized in that, The temperature for fermentation in step 2 is preferably 30℃, the relative humidity is preferably 85%, and the fermentation time is preferably 10 hours.

4. The mulberry leaf tea beverage and the preparation method thereof according to claim 1, characterized in that, In step 3, the steaming temperature is preferably 105℃, and the steaming time is preferably 6 minutes.

5. The mulberry leaf tea beverage and the preparation method thereof according to claim 1, characterized in that, In step 4, the ratio of the mixed raw materials is 80 parts of mulberry leaves and 20 parts of raw cassia seed powder.

6. A mulberry leaf tea beverage and a method of preparing the same according to claim 1, characterized in that, In step 6, the fermentation temperature is preferably 30℃, the humidity is preferably 80%, and the fermentation time is preferably 8 days.

7. The mulberry leaf tea beverage and the preparation method thereof according to claim 1, characterized in that, In addition, step 7 is included: dry the fermented tea cakes at 60℃ until the moisture content is less than 6%, and then store them at room temperature for 2 weeks.

8. A mulberry leaf tea beverage and a method of preparing the same according to claim 7, characterized in that, In addition, step 8 is included: extract the stored tea cakes at a temperature of 95℃ for 10-20 minutes, with a tea-to-water ratio of 1:40, and use 300-400W microwave-assisted extraction.

9. The mulberry leaf tea beverage and the preparation method thereof according to claim 8, characterized in that, In addition, step 9 is included: dilute the extracted liquid 4 times, add vitamin C and sodium bicarbonate, sterilize it at 136℃ for 15s UHT, cool it to 20℃, and then aseptically fill it to obtain the finished product.