A kind of polygonatum black tea and preparation method thereof

Abstract

The invention discloses a preparation method of polygonatum black tea, which comprises extracting polygonatum water extract and treating tea leaves, and preparing polygonatum black tea through withering tea leaves, adding polygonatum water extract, rolling tea leaves, fermenting tea leaves, drying tea leaves, and aroma-raising steps. The polygonatum black tea prepared by the invention is compared with the black tea processed by the traditional process. The black tea made by the traditional process of spring tea leaves has some varieties with heavy green taste, fresh and mellow tea soup, and insufficient sweetness. The black tea made by the traditional process of summer and autumn tea leaves has the problems of heavy bitter taste, grassy taste, insufficient aroma, low freshness, and other poor quality. The polygonatum black tea processed by the invention, especially the summer and autumn tea, has the advantages of roasted sweet potato fragrance of dry tea, dark and moist dry tea, bright black, tight, richer tea soup taste, brighter color, and sufficient sweetness, which well improves the shortcomings of black tea processed by summer and autumn tea leaves, such as heavy bitter taste, grassy taste, insufficient aroma, and low freshness.

Description

Technical Field

[0001] The present invention relates to a tea preparation technology, in particular to a polygonatum black tea added with polygonatum water extract and a preparation method thereof. Background Art

[0002] Black tea ranks first in the world in terms of production among all types of tea and is highly favored by consumers. However, the temperature is high and the sunshine is strong during the growing season of summer and autumn tea leaves. The tea polyphenols and caffeine content in the leaves is high, while the amino acids and aromatic substances content is low. Therefore, summer and autumn black tea made by traditional technology is prone to bitterness, grassiness, lack of aroma, low freshness and other poor quality problems. Therefore, summer and autumn tea is cheaper than spring tea and has relatively small profits. Improving the processing technology and developing high-quality summer and autumn tea leaves can also produce products with significantly higher tea polyphenols and amino acids than spring tea, increase free catechins, reduce bitterness in tea soup and reduce astringency. Some black teas made from spring tea varieties also have problems such as too strong grassiness, which affects the taste. Summary of the invention

[0003] The purpose of the present invention is to solve the deficiencies of the above-mentioned technology and provide a Huangjing black tea with sweet potato aroma in dry tea, rich tea soup flavor, good aftertaste, effectively reducing the bitterness and green taste of black tea and improving the aroma quality, and a preparation method thereof.

[0004] In order to achieve the above object, the present invention provides a method for preparing polygonatum black tea, comprising the following steps:

[0005] (1) Preparation of Polygonatum sibiricum water extract: Select fresh Polygonatum sibiricum in winter, slice its tubers and steam them in a steamer at a temperature below 100° C. for 1 hour, then control the temperature in an oven to be below 65° C. and bake for 30 minutes, repeat the steaming and baking process 6-7 times until the Polygonatum sibiricum slices change from light yellow or white to black or dark yellow-brown to obtain processed Polygonatum sibiricum; add 5 kg of purified water to 1 kg of processed Polygonatum sibiricum and boil them in a pressure cooker for 30 minutes, filter the solid and liquid of Polygonatum sibiricum under pressure through a 100-mesh filter to obtain Polygonatum sibiricum water extract, and cool the Polygonatum sibiricum water extract for standby use;

[0006] (2) Processing of Polygonatum sibiricum Red Tea: a. Withering of tea greens: The tea greens in spring are withered at 25-30°C for 22-25 hours, and the tea greens in summer and autumn are withered at 25-30°C for 20-22 hours; b. Addition of water extract of Polygonatum sibiricum: Based on the standard of 1 kg of tea greens, the total amount of water extract of Polygonatum sibiricum added is 10 to 15 ml of water extract of Polygonatum sibiricum per 1 kg of fresh tea greens, adjusted according to the picking season, variety, etc. of the tea greens; when the tea greens are withered to the point where the water extract of Polygonatum sibiricum needs to be added, the air supply volume of the blower in the spreading machine is increased by 20% compared to when there is no addition of water extract of Polygonatum sibiricum to the tea greens; when the tea greens are withered to 60%, gently turn the tea greens and spray 35% of the total amount of water extract of Polygonatum sibiricum with a sprayer, when the tea greens are withered to 70%, gently turn the tea greens and spray 30% of the total amount of water extract of Polygonatum sibiricum, when the tea greens are withered to 80%, gently turn the tea greens and spray 20% of the total amount of water extract of Polygonatum sibiricum, when the tea greens are withered to 90%, spray 15% of the total amount of water extract of Polygonatum sibiricum, and turn the tea greens vigorously 3-4 times until the withering of the tea greens is completed; c. Rolling of Polygonatum sibiricum Red Tea: The withered tea greens are transferred to a rolling machine. The rolling pressure of the tea greens of Polygonatum sibiricum Red Tea is set to be 10-15% higher than that of the traditional tea green rolling machine, and the rotational speed is reduced by 15-20%. The standard for the end of the rolling of the tea greens is that the cell damage rate of the tea green leaves reaches over 85% after rolling, the strip formation rate of the tea green leaves is over 90%, the strips are tightly coiled, the tea juice overflows fully and adheres to the surface of the tea green leaves. It is the best when tightly held by hand and the tea juice overflows but does not drip; visually observe that over 95% of the tea stalks turn from green to red, and when 60-70% of the edges of the tea green leaves show slight signs of fermentation, the rolling ends; d. Fermentation of Polygonatum sibiricum Red Tea: The tea greens that have been withered and rolled are put into a fermentation chamber for fermentation. The temperature of the fermentation chamber is set at 37°C - 40°C (where: 37-38°C in spring, 38-40°C in summer and autumn), and the humidity is controlled in the range of 95% - 96% for fermentation. After about 4-6 hours of fermentation, 95% of the central part of the tea stalks of the tea greens has turned from green to red, and over 80% of the whole tea green leaves have turned from green to red; e. Drying and flavor enhancement of Polygonatum sibiricum Red Tea: When the fermentation of Polygonatum sibiricum Red Tea is completed, it is dried and the flavor is enhanced. The drying temperature of Polygonatum sibiricum Red Tea is 90°C for 40 minutes, and the flavor enhancement temperature is 95°C for 10 minutes. Since Polygonatum sibiricum Red Tea adds water extract of Polygonatum sibiricum (the main component is polysaccharide of Polygonatum sibiricum) compared to traditional black tea, the polysaccharide of Polygonatum sibiricum is mixed with the inclusions in the tea leaf exudates during the rolling process of the tea greens. During the drying and flavor enhancement processes of Polygonatum sibiricum Red Tea, the temperatures are increased by 10°C and 5°C respectively, that is, the drying temperature of traditional black tea is 80°C for 40 minutes, and the flavor enhancement temperature is 90°C for 10 minutes.

[0007] In order to further achieve the technical effect of the present invention, the green tea is fresh tea leaves from spring or summer and autumn, with one bud and two leaves picked for spring tea and one bud and two or three leaves picked for summer and autumn tea as the standard; the thickness of the slices of the fresh Polygonatum sibiricum root tuber is 2-3 mm; the filtered Polygonatum sibiricum solid and liquid are obtained by pressure filtration through a 100-mesh filter to obtain a Polygonatum sibiricum water extract; in the process of adding the Polygonatum sibiricum water extract into the withered green tea, a drying machine is simultaneously provided to blow air to the green tea, and after the Polygonatum sibiricum water extract is added, the air supply of the blower in the drying machine is increased by 20% relative to when no Polygonatum sibiricum water extract is added.

[0008] The invention provides a method for preparing polygonatum black tea. According to the total amount of polygonatum water extract added as described above, 10 ml to 15 ml of polygonatum water extract is added to 1 kg of fresh green tea. Specifically, the proportion of polygonatum water extract can be adjusted according to tea tree varieties and seasons. For example, for spring green tea with low contents of substances such as caffeine and tea polyphenols and high contents of tea polysaccharides, the amount of polygonatum extract is 10 ml / kg green tea. For summer and autumn green tea with high contents of substances such as caffeine and tea polyphenols and strong bitter taste, the amount of polygonatum extract is increased to 12 ml / kg (summer) and 15 ml / kg (autumn) green tea, and the amount of white tea and high mountain tea is appropriately reduced to 12 g / kg green tea.

[0009] In the above preparation process, after the addition process of the polygonatum water extract is completed, the tea leaves are continued to be spread out until the gloss on the surface of the tea leaves disappears, the leaf color turns light, the green smell decreases, the fragrance is revealed, the leaf shape shrinks, the stems and veins lose water and become soft and not easy to break, the leaves are soft when pinched by hand, there is no friction sound, and they can be scattered when held tightly and released, the water of the polygonatum water extract sprayed on the surface of the tea leaves is completely evaporated, the withering of the tea leaves is completed, and then the completely withered tea leaves are transferred to a rolling machine for rolling, fermented in a fermentation machine, and dried to enhance the fragrance.

[0010] The present invention adopts spring, summer and autumn tea leaves and polygonatum water extract to process the polygonatum black tea. Compared with the black tea processed by the traditional process, the traditional process of spring tea leaves processed into black tea has some varieties with heavy green taste and light tea soup taste, while the summer and autumn tea leaves processed into black tea have the problems of poor quality such as heavy bitter taste, grassy taste, insufficient aroma, low freshness of tea soup, etc. The polygonatum black tea prepared by the method of the present invention improves the shortcomings of heavy green taste of spring tea processed black tea and heavy bitter taste, grassy taste, insufficient aroma, low freshness of summer and autumn tea processed black tea; the polygonatum black tea processed by the present invention, especially the summer and autumn tea dry tea has the advantages of roasted sweet potato fragrance, dark and moist dry tea, tight, black and bright color, richer tea soup taste, brighter color, and good sweetness, which has a good improvement effect on the shortcomings of summer and autumn tea processed black tea such as heavy bitter taste, grassy taste, insufficient aroma, and low freshness.

[0011] The present invention innovatively adds polygonatum water extract during the black tea processing process, changes the processing techniques such as fermentation and drying temperature during the processing, adjusts the rolling and drying parameters, improves the quality of tea leaves, increases the value of tea leaves, and processes black tea with a strong tea fragrance, rich tea soup flavor, and good aftertaste, effectively reduces the bitterness and green taste of black tea, improves the aroma quality, and processes high-quality black tea suitable for consumers. DETAILED DESCRIPTION

[0012] The preferred embodiments of the present invention are further described below by way of examples. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0013] Embodiment 1:

[0014] The present embodiment provides a method for preparing polygonatum black tea, comprising the following steps:

[0015] (1) Preparation of polygonatum water extract: select fresh polygonatum in winter, slice its tubers and steam them in a steamer at a temperature below 100° C. for 1 hour, then control the temperature in an oven to be below 65° C. and bake for 30 minutes, repeat the steaming and baking process 6-7 times until the polygonatum slices change from light yellow or white to black or dark yellow-brown to obtain processed polygonatum; add 5 kg of purified water to 1 kg of processed polygonatum in a pressure cooker for 30 minutes, heat the pressure cooker at room temperature and under natural conditions during the cooking, and control the pressure in the pressure cooker to be between 40 KPa and 60 KPa, then filter the solid and liquid of polygonatum to obtain polygonatum water extract, and cool the polygonatum water extract for standby use;

[0016] (2) Processing of Polygonatum sibiricum black tea: a. Withering of green tea leaves, {when the green tea leaves wither to the point where Polygonatum sibiricum water extract needs to be added, the air supply volume of the blower in the airing machine is increased by 20% relative to the green tea leaves without the addition of Polygonatum sibiricum water extract}: the green tea leaves wither for 22-25 hours in a 25-30℃ environment in spring, and for 20-22 hours in a 25-30℃ environment in summer and autumn; b. Addition of Polygonatum sibiricum water extract: the green tea leaves are based on the standard of 1 kg, and the total amount of Polygonatum sibiricum water extract added is 10 to 15 ml of Polygonatum sibiricum water extract for 1 kg of fresh green tea leaves, which is adjusted according to the picking season and variety of the green tea leaves; when the green tea leaves wither to the point where Polygonatum sibiricum water extract needs to be added, the air supply volume of the blower in the airing machine is increased by 20% relative to the green tea leaves without the addition of Polygonatum sibiricum water extract When the tea leaves wither to 60%, gently turn the tea leaves and spray 35% of the total amount of the water extract of polygonatum with a spray bottle. When the tea leaves wither to 70%, gently turn the tea leaves and spray 30% of the total amount of the water extract of polygonatum with a spray bottle. When the tea leaves wither to 80%, gently turn the tea leaves and spray 20% of the total amount of the water extract of polygonatum with a spray bottle. When the tea leaves wither to 90%, 15% of the total amount of the water extract of polygonatum with a spray bottle is used. The tea leaves are turned over 3-4 times with a big movement until the withering of the tea leaves is completed. c. Rolling of polygonatum black tea: The withered tea leaves are transferred to the rolling machine. The rolling pressure of the polygonatum black tea leaves is set to increase the pressure by 10-15% compared with the traditional tea leaves rolling machine, and the speed is reduced by 15-20%. The tea leaves are rolled until the cell destruction rate of the tea leaves reaches more than 85%. The rolling is finished when the leaf stripping rate is more than 90%, the strips are tightly rolled, the tea juice fully overflows and adheres to the surface of the green tea leaves. When the leaves are held tightly by hand, the tea juice overflows without dripping. It is observed by naked eyes that more than 95% of the tea stems have turned from green to red, and 60-70% of the edges of the green tea leaves show slight signs of fermentation; d. Fermentation of Polygonatum odoratum black tea: The withered and rolled green tea leaves are put into the fermentation room for fermentation. The temperature of the fermentation room is set at 37℃-39℃ (including: 37-38℃ in spring, 38-40℃ in summer and autumn), and the humidity is controlled at 95%-96% for fermentation. After about 4-6 hours of fermentation, 95% of the central part of the tea stems of the green tea leaves has turned from green to red, and more than 80% of the entire green tea leaves have turned from green to Red; e. Drying and aroma enhancement of polygonatum black tea: After the fermentation of polygonatum black tea is completed, it is dried and aroma enhanced. The drying temperature of polygonatum black tea is 90°C for 40 minutes (the traditional black tea drying temperature is 80°C for 10 minutes), and the aroma enhancement temperature of polygonatum black tea is 95°C for 10 minutes (the traditional black tea aroma enhancement temperature is 80°C for 10 minutes). Since polygonatum black tea contains polygonatum water extract (main ingredient polygonatum polysaccharide) compared to traditional black tea, polygonatum polysaccharide is mixed with the contents of tea precipitates during the rolling process of green tea leaves. The temperature of polygonatum black tea in the drying and aroma enhancement process is 10°C and 5°C higher than that of traditional black tea production, namely, the traditional black tea is dried at 80°C for 40 minutes and the aroma enhancement temperature is 90°C for 10 minutes.

[0017] This embodiment selects spring tea leaves and Polygonatum sibiricum water extract to process Polygonatum sibiricum black tea, which is composed of the following raw materials by weight: 10 kg of fresh tea leaves, tea leaves picking standard 1 bud 2 leaves, 100 ml-150 ml of Polygonatum sibiricum water extract, and the tea leaves are three varieties of Jinguanyin, Jingbai No. 3, and Jiukeng group species. In the process of picking and processing tea leaves, choose the first and middle ten days of April in spring, the tea buds grow to 1 bud 2 leaves, pick them before 10 o'clock in the morning, and spread them evenly on the withering machine, the thickness of the tea leaves is 4-5 cm, the temperature of the withering machine is set at 25°C, and the wind force of the blower is level 3.

[0018] Addition of Polygonatum sibiricum water extract: Pick the tea leaves of three varieties, Jin Guanyin, Jingbai No. 2, and Jiukeng group, in the morning, weigh 10 kg, and spread them evenly on the withering machine. Use a measuring cup to measure 3 portions of 100 ml of Polygonatum sibiricum water extract, and put them into a scaled spray bottle respectively. When the three varieties of tea leaves wither to 60% (the wind force of the blower of the cooling machine is level 4), gently turn the tea leaves and spray 35% of the total amount of Polygonatum sibiricum water extract, i.e. 35 ml, with a spray bottle. When the tea leaves wither to 70%, gently turn the tea leaves and spray 30% of the total amount of Polygonatum sibiricum extract, i.e. 30 ml, and at the same time increase the air supply of the blower of the drying machine by 20%. When the tea leaves wither to 80%, gently turn the tea leaves and spray 20% of the total amount of Polygonatum sibiricum extract, i.e. When the tea leaves are withered to 90%, spray 15% of the total amount of polygonatum extract, i.e. 15 ml. Turn the tea leaves over 3-4 times with great force and continue to dry them until the water of the polygonatum extract sprayed on the surface of the tea leaves is completely evaporated. The luster on the surface of the tea leaves disappears, the leaf color turns light, the green smell decreases, the leaf shape shrinks, the stems and veins lose water and become soft and not easy to break. The leaves feel soft when pinched by hand, without friction sound, and can be scattered when clenched into a ball and released. The withering of the tea leaves is over.

[0019] Huangjing black tea rolling: After the tea leaves wither, they are transferred to the rolling machine. The rolling pressure of spring Huangjing black tea is 15% higher than that of traditional tea leaves, and the speed is reduced by 15-20%. The tea leaves are rolled until the cell destruction rate reaches more than 85%, the leaf strip rate is more than 90%, the strips are tightly rolled, the tea juice fully overflows and adheres to the surface of the tea leaves. When the tea juice overflows without dripping, it is the best. The rolling is finished when more than 95% of the tea stems turn from green to red by naked eye, and 60-70% of the edges of the tea leaves show slight signs of fermentation. The standards for the end of rolling for traditional black tea and Huangjing black tea are the same.

[0020] Fermentation of Polygonatum odoratum black tea: The withered and rolled green tea leaves are placed in the fermentation room for fermentation. The temperature of the fermentation room is set at 37-38℃. The temperature of the fermentation room in spring and autumn is 2-3℃ higher than that of traditional black tea. The temperature of the fermentation room is 35℃ for traditional black tea and 37-38℃ for Polygonatum odoratum black tea. The humidity is controlled in the range of 95%-96% for fermentation. After about 4-6 hours of fermentation, 95% of the center part of the tea stems of the green tea leaves has turned from green to red, and more than 80% of the whole leaves of the green tea have turned from green to red, and the fermentation is ended. The standards for the end of fermentation of traditional black tea and Polygonatum odoratum black tea are the same.

[0021] Drying and aroma enhancement of Polygonatum sibiricum black tea: When the fermentation of Polygonatum sibiricum black tea is completed, it needs to be dried and aroma enhanced. Since Polygonatum sibiricum black tea contains more Polygonatum sibiricum water extract (the main ingredient is Polygonatum sibiricum polysaccharide) than traditional black tea, Polygonatum sibiricum polysaccharide is mixed with the contents of tea precipitates during the rolling process of tea leaves. The temperature of Polygonatum sibiricum black tea is increased by 10 and 5°C respectively during the drying and aroma enhancement process. That is, the traditional black tea is dried at 80°C for 40 minutes, the Polygonatum sibiricum black tea is dried at 90°C for 40 minutes, the traditional black tea aroma enhancement temperature is 90°C for 10 minutes, and the Polygonatum sibiricum black tea is dried at 95°C for 10 minutes.

[0022] Embodiment 2:

[0023] This embodiment describes a polygonatum black tea processed from summer green tea leaves and polygonatum water extract, which is composed of the following raw materials in parts by weight: 10 kg of fresh green tea leaves, standard picking of green tea leaves with 1 bud and 2 leaves or 1 bud and 3 leaves, 120 ml of polygonatum water extract, and the green tea varieties are three varieties: Jin Guanyin, Jingbai No. 3, and Jiukeng group species.

[0024] (1) Picking and processing of green tea leaves: In the early to mid-May of summer, when the tea buds grow to 1 bud and 2 or 3 leaves, the picking is completed before 10 am and the tea leaves are evenly spread on the withering machine. The thickness of the green tea leaves is 4-5 cm. The temperature of the withering machine is set at 25℃ and the blower wind speed is level 3.

[0025] (2) Adding Polygonatum sibiricum water extract: Pick the tea leaves of three varieties, namely, Jin Guanyin, Jingbai No. 3, and Jiukeng group, in the morning, weigh 10 kg, and spread them evenly on the withering machine. Use a measuring cup to measure 3 portions of 120 ml of Polygonatum sibiricum water extract, and put them into a scaled spray bottle. When the three varieties of tea leaves wither to 60% (the wind force of the blower of the cooling machine is level 4), gently turn the tea leaves and spray 35% of the total amount of Polygonatum sibiricum water extract, i.e. 42 ml, with the spray bottle. When the tea leaves wither to 70%, gently turn the tea leaves and spray 30% of the total amount of Polygonatum sibiricum extract, i.e. 36 ml, and increase the air supply of the blower of the drying machine by 20%. When the tea leaves wither to 80%, gently turn the tea leaves and spray 20% of the total amount of Polygonatum sibiricum extract, i.e. When the tea leaves are withered to 90%, spray 15% of the total amount of polygonatum extract, i.e. 18 ml. Turn the tea leaves over 3-4 times with great force and continue to dry them until the water of the polygonatum extract sprayed on the surface of the tea leaves is completely evaporated. The luster on the surface of the tea leaves disappears, the leaf color turns light, the green smell decreases, the leaf shape shrinks, the stems and veins lose water and become soft and not easy to break. The leaves feel soft when pinched by hand, without friction sound, and can be scattered when clenched into a ball and released. The withering of the tea leaves is over.

[0026] (3) Rolling of Huangjing black tea: After the tea leaves wither, they are transferred to the rolling machine. In summer, the rolling pressure of Huangjing black tea is set to be 15% higher than that of traditional tea leaves, and the rotation speed is reduced by 15-20%. The tea leaves are rolled until the cell destruction rate reaches more than 85%, the leaf strip rate reaches more than 90%, the strips are tightly rolled, the tea juice fully overflows and adheres to the surface of the tea leaves. When the tea leaves are held tightly by hand, the tea juice overflows without dripping. Rolling is completed when more than 95% of the tea stems turn from green to red by naked eye observation, and 60-70% of the edges of the tea leaves show slight signs of fermentation. The standards for the end of rolling of traditional black tea and Huangjing black tea are the same.

[0027] (4) Fermentation of Polygonatum odoratum black tea: The withered and rolled green tea leaves are placed in a fermentation room for fermentation. The temperature of the fermentation room is set at 38-40°C. In summer and autumn, the temperature of the fermentation room is 3-4°C higher than that of traditional black tea. The temperature of the fermentation room is 35°C for traditional black tea and 38-39°C for Polygonatum odoratum black tea. The humidity is controlled at 95%-96% for fermentation. After about 4-6 hours of fermentation, 95% of the center part of the tea stems of the green tea leaves has turned from green to red, and more than 80% of the entire tea leaves have turned from green to red. The fermentation is completed. The standards for the end of fermentation of traditional black tea and Polygonatum odoratum black tea are the same.

[0028] (5) Drying and aroma enhancement of Polygonatum sibiricum black tea: When the fermentation of Polygonatum sibiricum black tea is completed, it needs to be dried and aroma enhanced. Compared with traditional black tea, Polygonatum sibiricum black tea contains Polygonatum sibiricum water extract (the main ingredient is Polygonatum sibiricum polysaccharide), which is mixed with the precipitates of tea leaves during the rolling process of green tea leaves. The drying temperature of Polygonatum sibiricum black tea is 90°C for 40 minutes, and the drying temperature is 95°C for 10 minutes.

[0029] Embodiment 3:

[0030] This embodiment 3 describes a polygonatum black tea processed from autumn green tea leaves and polygonatum water extract, which is composed of the following raw materials in parts by weight: 10 kg of fresh green tea leaves, standard 1 bud and 2 leaves of green tea leaves, 150 ml of polygonatum water extract, and the green tea varieties are three varieties: Jin Guanyin, Jingbai No. 3, and Jiukeng group species.

[0031] (1) Picking and processing of green tea leaves: In autumn, from mid-August to early to mid-October, when the tea buds grow to 1 bud and 2 or 3 leaves, the picking should be completed before 10 a.m. and the tea leaves should be evenly spread on the withering machine. The thickness of the green tea leaves should be 4-5 cm. The temperature of the withering machine should be set at 25°C and the blower should be at level 2.

[0032] (2) Adding Polygonatum sibiricum water extract: Pick the three varieties of tea leaves, Jin Guanyin, Jingbai No. 3, and Jiukeng group, in the morning, weigh 10 kg, and spread them evenly on the withering machine. Use a measuring cup to measure 3 portions of 150 ml of Polygonatum sibiricum water extract, and put them into scaled spray bottles respectively. When the three varieties of tea leaves have withered to 60%, gently turn the tea leaves over and spray 35% (52.5 ml) of the total amount of polygonatum water extract with a spray bottle; when the tea leaves have withered to 70%, gently turn the tea leaves over and spray 30% (45 ml) of the total amount of polygonatum extract with a spray bottle; at the same time, increase the air supply of the blower of the air drying machine by 20%; when the tea leaves have withered to 80%, gently turn the tea leaves over and spray 20% (30 ml) of the total amount of polygonatum extract with a spray bottle; when the tea leaves have withered to 90%, spray 15% (22.5 ml) of the total amount of polygonatum extract with a spray bottle; turn the tea leaves over 3-4 times with large movements, and continue to air dry until the water in the polygonatum water extract sprayed on the surface of the tea leaves has completely evaporated, the gloss on the surface of the tea leaves has disappeared, the leaf color has turned light, the green smell has diminished, the leaf shape has shrunk, the stems and veins have lost water and become soft and not easy to break, the leaves feel soft when pinched, there is no friction sound, and they can bounce off when held tightly and released, and the withering of the tea leaves is over.

[0033] (3) Rolling of Huangjing Black Tea: After the withering of the tea leaves, the tea leaves are transferred to the rolling machine. The rolling pressure of autumn Huangjing Black Tea is 15% higher than that of traditional tea leaves, and the rotation speed is reduced by 15-20%. The tea leaves are rolled until the cell destruction rate reaches more than 85%, the leaf strip rate reaches more than 90%, the strips are tightly rolled, the tea juice fully overflows and adheres to the surface of the tea leaves. When the tea leaves are held tightly by hand, the tea juice overflows without dripping. Rolling is completed when more than 95% of the tea stems turn from green to red by naked eye observation, and 60-70% of the edges of the tea leaves show slight signs of fermentation. The standards for the end of rolling of traditional black tea and Huangjing Black Tea are the same.

[0034] (4) Fermentation of Polygonatum odoratum black tea: The withered and rolled green tea leaves are placed in a fermentation room for fermentation. The temperature of the fermentation room is set at 38-39°C. The temperature of the fermentation room in summer and autumn is 4-5°C higher than the traditional temperature. The temperature of the fermentation room is 35°C for traditional black tea and 39°C-40°C for Polygonatum odoratum black tea. The humidity is controlled at 95%-96% for fermentation. After about 4-6 hours of fermentation, 95% of the center part of the tea stems of the green tea leaves has turned from green to red, and more than 80% of the entire tea leaves have turned from green to red. The fermentation is completed. The standards for the end of fermentation of traditional black tea and Polygonatum odoratum black tea are the same.

[0035] (5) Drying and aroma enhancement of Polygonatum sibiricum black tea: When the fermentation of Polygonatum sibiricum black tea is completed, it needs to be dried and aroma enhanced. Compared with traditional black tea, Polygonatum sibiricum black tea contains Polygonatum sibiricum water extract (the main ingredient is Polygonatum sibiricum polysaccharide), and Polygonatum sibiricum polysaccharide is mixed with the contents of tea precipitates during the rolling process of green tea leaves. The temperature of Polygonatum sibiricum black tea is increased by 10 and 5°C during the drying and aroma enhancement process, respectively. That is, the drying temperature of Polygonatum sibiricum black tea is 90°C for 40 minutes, and the aroma enhancement temperature is 95°C for 10 minutes.

[0036] The comparison between the polygonatum black tea obtained in the above example and the traditional black tea is shown in the following "black tea evaluation table":

[0037] Black Tea Evaluation Table

[0038]

[0039]

Claims

1. A method for preparing polygonatum black tea, The following steps are involved: (1) Preparation of Polygonatum sibiricum water extract: Select fresh Polygonatum sibiricum in winter, slice its tubers and steam them in a steamer at a temperature of less than 100° C. for 1 hour, then control the temperature in an oven to bake at 65° C. for 30 minutes, and repeat the steaming and baking process 6-7 times until the Polygonatum sibiricum slices change from light yellow or white to black or dark yellow-brown to obtain processed Polygonatum sibiricum; add 5 kg of purified water to 1 kg of processed Polygonatum sibiricum and boil them in a pressure cooker for 30 minutes, filter out the cooled Polygonatum sibiricum solid liquid through a 100-mesh filter to remove the Polygonatum sibiricum solid matter, and obtain the Polygonatum sibiricum water extract for standby use; (2) Processing of Polygonatum sibiricum black tea: a. Withering of green tea leaves: When the green tea leaves are withered to the point where Polygonatum sibiricum water extract needs to be added, the air supply of the blower in the airing machine is increased by 20% compared to the green tea leaves without the addition of Polygonatum sibiricum water extract. In spring, the green tea leaves are withered for 22-25 hours at 25-30℃, and in summer and autumn, the green tea leaves are withered for 20-22 hours at 25-30℃. b. Addition of Polygonatum sibiricum water extract: The green tea leaves are based on 1 kg of standard, and the total amount of Polygonatum sibiricum water extract added is 100%. The amount is 10 to 15 ml of Polygonatum sibiricum water extract for 1 kg of fresh green tea. When the green tea withers to 60%, gently turn the green tea and spray 35% of the total amount of Polygonatum sibiricum water extract with a spray bottle. When the green tea withers to 70%, gently turn the green tea and spray 30% of the total amount of Polygonatum sibiricum water extract. When the green tea withers to 80%, gently turn the green tea and spray 20% of the total amount of Polygonatum sibiricum water extract. When the green tea withers to 90%, turn the green tea 3-4 times with a big movement. Spray 15% of the total amount of Polygonatum sibiricum water extract at the same time until the tea leaves wither. c. Rolling of Polygonatum sibiricum black tea: The tea leaves withering are transferred to the rolling machine. The rolling pressure of Polygonatum sibiricum black tea is set to be 10-15% higher than that of the traditional tea leaves rolling machine, and the speed is reduced by 15-20%. Rolling is completed when more than 95% of the tea stems turn from green to red by naked eye observation, and 60-70% of the edges of the tea leaves show slight signs of fermentation. d. Fermentation of Polygonatum sibiricum black tea: The withered and rolled green tea leaves are put into the fermentation room for fermentation. The temperature of the fermentation room is set at 37℃-39℃, including: 37-38℃ in spring, 38-40℃ in summer and autumn, and the humidity is controlled in the range of 95%-96% for fermentation. After 4-6 hours of fermentation, 95% of the central part of the tea stems of the green tea leaves turns from green to red, and more than 80% of the whole leaves of the green tea leaves turn from green to red; e. Drying and aroma enhancement of Polygonatum sibiricum black tea: After the fermentation of Polygonatum sibiricum black tea is completed, it is dried and aroma enhancement. The drying temperature of Polygonatum sibiricum black tea is 90℃ for 40 minutes. After drying, the aroma enhancement temperature of Polygonatum sibiricum black tea is 95℃ for 10 minutes.

2. The method for preparing polygonatum black tea according to claim 1, Its characteristics are The green tea is fresh tea leaves from spring or summer and autumn, with one bud and two leaves picked for spring tea and one bud and two or three leaves picked for summer and autumn tea as the standard; the thickness of the slices of the fresh Polygonatum sibiricum root tuber is 2-3 mm; the filtering of the solid liquid of Polygonatum sibiricum is performed by pressure filtration through a 100-mesh filter; during the process of adding the Polygonatum sibiricum water extract into the withered green tea, a drying machine is simultaneously provided to blow air to the green tea, and after the addition of the Polygonatum sibiricum water extract to the green tea, the air supply of the blower in the drying machine is increased by 20% relative to the green tea to which the Polygonatum sibiricum water extract is not added.

3. A polygonatum black tea obtained according to the preparation method of polygonatum black tea according to claim 1.

Images