阅读说明：本技术 一种利用冬瓜及冬瓜发酵物消减茶叶涩味的方法 (Method for reducing astringent taste of tea by using wax gourd and wax gourd fermentation product ) 是由 向识地 于 2021-09-23 设计创作，主要内容包括：本发明公开了一种利用冬瓜及冬瓜发酵物消减茶叶涩味的方法,先利用冬瓜粉与苜蓿粉制备低温萃取液,利用冬瓜提取液和乳酸菌制备冬瓜发酵液；然后对茶叶的制备工艺进行改进,将除杂后的茶鲜叶预晾晒后移至室内,雾化喷洒低温萃取液得到二次茶鲜叶,再将二次茶鲜叶进行蒸汽杀青,杀青完成后雾化喷洒稀释过的冬瓜发酵液静置后回潮,并对回潮后的回潮叶进行揉捻、低温风干后再次雾化喷洒低温萃取液,保持20～30min后干燥至含水量5％以下即得祛涩后的成品茶叶。本发明通过冬瓜及冬瓜发酵物对低品质茶叶进行提香,并降低茶叶的茶多酚以及花青素含量,能大幅改善茶叶中的涩感并中和茶叶中的苦味。(The invention discloses a method for reducing astringent taste of tea by using wax gourd and wax gourd fermentation product, which comprises the steps of preparing low-temperature extract liquid by using wax gourd powder and alfalfa powder, and preparing wax gourd fermentation liquid by using wax gourd extract liquid and lactic acid bacteria; and then improving the preparation process of the tea, pre-airing the fresh tea leaves after impurity removal, moving the fresh tea leaves into a room, atomizing and spraying a low-temperature extraction liquid to obtain secondary fresh tea leaves, then carrying out steam enzyme deactivation on the secondary fresh tea leaves, atomizing and spraying diluted wax gourd fermentation liquid after the enzyme deactivation, standing, humidifying, kneading and twisting the humidified leaves, drying at low temperature, atomizing and spraying the low-temperature extraction liquid again, keeping the temperature for 20-30 min, and drying until the water content is below 5% to obtain the finished product tea after astringency removal. According to the invention, the low-quality tea is subjected to aroma improvement through the wax gourd and the wax gourd fermentation product, the content of tea polyphenol and anthocyanin in the tea is reduced, the astringency in the tea can be greatly improved, and the bitter taste in the tea can be neutralized.)

1. A method for reducing astringent taste of tea by using wax gourd and wax gourd fermentation products is characterized by comprising the following operation steps:

s1, preparing a low-temperature extraction liquid with the mass ratio of the wax gourd powder to the alfalfa powder being 5: 1-10: 1;

s2, fermenting the white gourd extracting solution, taking lactic acid bacteria as fermenting bacteria, and fermenting in a fermentation medium at the temperature of 32-37 ℃ and under the condition of pH 5-6, wherein the fermentation time is controlled to be 36-48 h, so as to obtain a white gourd fermentation liquid;

s3, removing impurities from fresh tea leaves serving as raw materials, removing non-tea impurities, naturally airing to enable the water content of the fresh tea leaves to be 65-70%, then moving the fresh tea leaves indoors, and uniformly spraying the low-temperature extraction liquid prepared in the step S1 to the surface of the fresh tea leaves which are aired and moved indoors by using an atomizer to obtain secondary fresh tea leaves;

s4 steam deactivating the secondary fresh tea leaves obtained through the step S3;

s5, flattening the de-enzymed leaves obtained by the steam de-enzyming in the step S4, diluting the wax gourd fermentation liquor with sterile water to the mass ratio of 3-5%, uniformly spraying the diluted wax gourd fermentation liquor to the surfaces of the de-enzymed leaves by using an atomizer, and performing moisture regain treatment after keeping for 6-8 hours;

s6, directly rolling the moisture regaining leaves after moisture regaining treatment, air-drying the rolled tea at low temperature after rolling until the water content of the tea is 15-20%, uniformly spraying the low-temperature extraction liquid prepared in the step S1 to the surfaces of the air-dried leaves by using an atomizer, keeping the temperature for 20-30 min, and drying until the water content is below 5% to obtain the finished product tea with the astringent taste removed.

2. The method for reducing astringency of tea leaves by using wax gourd and its fermented product according to claim 1, wherein in the low temperature extraction in step S1, wax gourd powder and alfalfa powder satisfying the mass ratio are added to low temperature water 8-15 times the mass of the wax gourd powder and alfalfa powder, the water temperature is controlled to 10-15 ℃, the ultrasonic frequency is 30-60 kHz, and the low temperature extraction liquid is obtained.

3. The method for reducing astringency of tea leaves using wax gourd and its fermented product according to claim 1, wherein the fermentation substrate used in step S2 is inoculated with an inoculation amount of 8 to 10% by using maltose, glucose or sucrose as a carbon source in an amount of 5 to 8% of the fermentation substrate, and the inoculated fermentation substrate is placed in an incubator under controlled conditions for continuous fermentation culture.

4. The method for reducing astringency of tea leaves using wax gourd and its fermented product as claimed in claim 1, wherein the amount of spraying the low temperature extraction liquid onto the surface of the fresh tea leaves in step S3 is 20-30 ml/kg; and the blades are flattened as much as possible during spraying of the low-temperature extraction liquid so as to ensure the spraying uniformity.

5. The method for reducing astringency of tea leaves by using wax gourd and wax gourd fermented product according to claim 1, wherein the amount of spraying the low temperature extract on the surface of the air-dried leaves in step S6 is 10-15 ml/kg; and the blades are flattened as much as possible during spraying of the low-temperature extraction liquid so as to ensure the spraying uniformity.

6. The method for reducing astringency of tea leaves using wax gourd and its fermented product as claimed in claim 1, wherein the steaming is performed at a steaming temperature of 100-120 ℃ for 45-60S at the steaming step of S4.

7. The method for reducing astringency of tea leaves using wax gourd and its fermented product according to claim 1, wherein the amount of the wax gourd fermented liquid diluted in step S5 sprayed on the surface of the blanched leaves is 10 to 15ml/kg of the blanched leaves.

8. The method for reducing astringency of tea leaves according to claim 1, wherein the temperature is kept at 25 to 38 ℃, the humidity is kept at 70 to 80% and the moisture-regaining time is kept at 30 to 60min during the moisture-regaining treatment in step S5.

9. The method for reducing astringency of tea leaves using wax gourd and its fermented product according to claim 1, wherein the rolling operation is performed on a bamboo-knitted operation panel placed on the surface of the hot water pot in step S6, and the temperature of the hot water in the hot water pot is controlled to be 50-60 ℃.

10. The method for reducing astringency of tea leaves using wax gourd and its fermented product as claimed in claim 1, wherein the drying is performed by full fire at step S6 until the water content is 5% or less.

Technical Field

The invention relates to the technical field of tea processing, in particular to a method for reducing astringent taste of tea by using wax gourd and wax gourd fermentation products.

Background

The green tea is one of the main tea types in China, the color of the dry tea and the tea soup and the tea bottom after brewing are mainly green, has the effects of restoring consciousness and refreshing, promoting urination and relieving fatigue, relieving fatigue and resisting aging, and plays an important role in food culture of Chinese people.

Astringency in tea has always been a field of major concern of tea enterprises and tea researchers, and generally, two major classes of tea polyphenol and alkaloid are considered as substances of green tea which dominate the bitter and astringent taste of tea. The temperature is moderate in spring, the rainfall is abundant, and the tea trees have a longer period of rest and health preservation in the first autumn and winter, so that the nutrient components in the body are rich, so that the amino acid and the multivitamins in the spring tea are rich, the spring tea has fresh and cool taste, strong fragrance and higher quality, and the green tea spring tea with excellent quality does not need to be subjected to debitterizing treatment intentionally; the proportion of amino acids and vitamins in spring tea and tea in summer and autumn, which are prepared from middle and low grade fresh leaves, can be obviously reduced, and the contents of anthocyanin, caffeine and tea polyphenol can be obviously increased, so that the bitter taste of the tea is increased, and the tea needs to be improved to meet the requirements of quality and taste.

The traditional green tea processing technology comprises five basic steps of spreading, deactivating enzyme, rolling, drying and raw tea, and the bitter taste of a green tea finished product is reduced mainly through the deactivating enzyme step, so that the deactivating enzyme plays a decisive role in the quality of the green tea, the characteristic of enzyme in fresh leaves can be destroyed through high-temperature deactivating enzyme, polyphenol substances are prevented from being oxidized, partial water in the leaves is evaporated, the leaves are softened, and conditions are created for rolling and shaping; in the prior art, green tea is improved mainly by optimizing a de-enzyming process, but the problem of heavy bitter taste cannot be effectively solved by improving the traditional green tea processing process, and a satisfactory effect cannot be achieved.

Disclosure of Invention

The invention aims to provide a method for reducing the astringent taste of tea by using wax gourd and wax gourd fermentation products, which can treat the tea of middle and low grade spring tea and summer and autumn tea to reduce the astringent taste of the tea so as to improve the brewing taste of the prepared tea.

The technical problem solved by the invention is realized by adopting the following technical scheme:

a method for reducing astringent taste of tea by using wax gourd and wax gourd fermentation product specifically comprises the following operation steps:

s1, preparing a low-temperature extraction liquid with the mass ratio of the wax gourd powder to the alfalfa powder being 5: 1-10: 1;

s2, fermenting the white gourd extracting solution, taking lactic acid bacteria as fermenting bacteria, and fermenting in a fermentation medium at the temperature of 32-37 ℃ and under the condition of pH 5-6, wherein the fermentation time is controlled to be 36-48 h, so as to obtain a white gourd fermentation liquid;

s3, removing impurities from fresh tea leaves serving as raw materials, removing non-tea impurities, naturally airing to enable the water content of the fresh tea leaves to be 65-70%, then moving the fresh tea leaves indoors, and uniformly spraying the low-temperature extraction liquid prepared in the step S1 to the surface of the fresh tea leaves which are aired and moved indoors by using an atomizer to obtain secondary fresh tea leaves;

s4 steam deactivating the secondary fresh tea leaves obtained through the step S3;

s5, flattening the de-enzymed leaves obtained by the steam de-enzyming in the step S4, diluting the wax gourd fermentation liquor with sterile water to the mass ratio of 3-5%, uniformly spraying the diluted wax gourd fermentation liquor to the surfaces of the de-enzymed leaves by using an atomizer, and performing moisture regain treatment after keeping for 6-8 hours;

s6, directly rolling the moisture regaining leaves after moisture regaining treatment, air-drying the rolled tea at low temperature after rolling until the water content of the tea is 15-20%, uniformly spraying the low-temperature extraction liquid prepared in the step S1 to the surfaces of the air-dried leaves by using an atomizer, keeping the temperature for 20-30 min, and drying until the water content is below 5% to obtain the finished product tea with the astringent taste removed.

As a further limitation, when low-temperature extraction is performed in step S1, the wax gourd powder and the alfalfa powder meeting the mass ratio are added into low-temperature water 8-15 times the mass of the wax gourd powder and the alfalfa powder, low-temperature ultrasonic extraction is performed at a temperature of 10-15 ℃ and an ultrasonic frequency of 30-60 kHz, and the low-temperature extraction liquid is obtained.

Further, in the step S2, the fermentation substrate is inoculated with an inoculation amount of 8 to 10% by using maltose, glucose or sucrose as a carbon source in an amount of 5 to 8% of the fermentation substrate, and the inoculated fermentation substrate is placed in an incubator to perform continuous fermentation culture under controlled conditions.

As a further limitation, in step S3, the spraying amount of the low-temperature extraction liquid on the surface of the fresh tea leaves is 20-30 ml/kg; in step S6, spraying the low-temperature extraction liquid on the surfaces of the air-dried leaves, wherein the spraying amount of the low-temperature extraction liquid is 10-15 ml/kg of air-dried leaves; and the blades are flattened as much as possible during spraying of the low-temperature extraction liquid so as to ensure the spraying uniformity.

As a further limitation, when the steam fixation is performed in the step S4, the fixation temperature is 100-120 ℃, and the fixation time is controlled to be 45-60S.

Further, the spraying amount of the wax gourd fermentation liquid diluted in the step S5 on the surface of the killed leaves is 10-15 ml/kg of the killed leaves.

Further, the temperature is maintained at 25 to 38 ℃, the humidity is maintained at 70 to 80%, and the moisture-regaining time is 30 to 60min when the moisture-regaining treatment is performed in step S5.

More specifically, when the rolling operation is performed in step S6, the rolling operation is performed on a bamboo-knitted operating surface, the bamboo-knitted operating surface is placed on the surface of the hot water pot, and the temperature of the hot water in the hot water pot is controlled to be 50 to 60 ℃.

As a further limitation, drying is performed by a full fire to a moisture content of 5% or less when drying is performed in step S6.

Has the advantages that: according to the method for reducing the astringent taste of the tea by using the wax gourd and the wax gourd fermentation product, the taste of the low-quality spring tea and the summer and autumn tea is improved by using the wax gourd extract and the wax gourd fermentation product matching process, so that the problem of resource utilization rate of the low-quality tea and the summer and autumn tea can be solved, the resource waste is reduced, the quality and efficiency improvement of the tea industry is realized, and the economic value is created;

the low-temperature extraction liquid of the wax gourd powder and the alfalfa powder can reduce the influence of alkaloid on the taste of the tea soup on the bitter taste of tea leaves under the condition of not changing the taste of the tea leaves, and the tea soup has the functions of reducing blood sugar, removing free radicals and improving sleep and constipation;

the problems of bitter and astringent taste and green odor generated by the traditional high-temperature tea frying technology can be effectively solved by steam de-enzyming, the problems of too fast water loss of the steam de-enzyming tea and easy generation of crushed materials in the rolling process can be relieved by atomization spraying of the low-temperature extraction liquid twice, and the sprayed low-temperature extraction liquid can be partially absorbed by the tea in the processing process so as to improve the tea quality by improving the fragrance of the tea;

the white gourd extract and the lactobacillus fermentation product are matched with the moisture regain and rolling process, so that the bitter taste of the tea can be covered by the fresh sweet of the white gourd after fermentation, and the fragrance of the white gourd after fermentation is very light, so that the tea fragrance cannot be influenced.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific embodiments.

In the following examples, it will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

In the first embodiment:

the method for reducing the astringent taste of tea by using the wax gourd and the wax gourd fermentation product is realized by the following operation steps:

firstly, preparing low-temperature extraction liquid of white gourd powder and alfalfa powder and white gourd fermentation liquor:

when the low-temperature extraction liquid is prepared, firstly, the white gourd powder and the alfalfa powder in the mass ratio of 5:1 are weighed as raw materials, the white gourd powder and the alfalfa powder are added into low-temperature water which is 12 times of the mass sum of the white gourd powder and the alfalfa powder, the water temperature of the low-temperature water is 10 ℃, and low-temperature ultrasonic extraction is carried out in the low-temperature water by utilizing ultrasonic waves with the frequency of 40kHz to obtain the low-temperature extraction liquid of the white gourd powder and the alfalfa powder.

During preparation, the wax gourd fermentation liquid is prepared by mixing a wax gourd extracting solution serving as a raw material with a fermentation substrate, controlling maltose accounting for 7% of the mass of the fermentation substrate to serve as a carbon source, inoculating 9% of the inoculation amount, placing the inoculated amount into an incubator, controlling the temperature to be 35-36 ℃ and the pH value to be 5.2-5.4, and carrying out continuous fermentation culture for 42 hours to obtain the wax gourd fermentation liquid.

Then tea processing is carried out, low-quality spring tea in the Hunan Shaoyang snow mountain area is selected as a raw material, picked fresh tea leaves are screened to remove impurities, sediment, metal and other non-tea impurities are removed, then the fresh tea leaves are naturally aired by the sun until the water content of the fresh tea leaves is reduced to 65-68%, then the aired fresh tea leaves are moved into a ventilation chamber, the prepared low-temperature extraction liquid is sprayed to the surfaces of the aired fresh tea leaves by an atomizer, 25-27 ml of the prepared low-temperature extraction liquid is sprayed to each kilogram of the prepared fresh tea leaves, the leaves are spread to the greatest extent during spraying to ensure the spraying uniformity, and at the moment, the fresh tea leaves can absorb part of the low-temperature extraction liquid to obtain secondary fresh tea leaves.

Performing steam enzyme deactivation when no water exists on the surfaces of the fresh tea leaves for the second time, controlling the enzyme deactivation temperature to be 100 ℃, performing enzyme deactivation for 45 seconds to obtain enzyme deactivated leaves, flattening the enzyme deactivated leaves, diluting the wax gourd fermentation liquor prepared in the previous step with sterile water until the mass ratio of the wax gourd fermentation liquor is 4%, adding the diluted wax gourd fermentation liquor into a new atomizer, spraying 10ml of the diluted wax gourd fermentation liquor to each kilogram of the enzyme deactivated leaves, keeping the diluted wax gourd fermentation liquor for 6 hours after spraying, performing moisture regain treatment, controlling the moisture regain temperature to be 32-35 ℃, the moisture regain humidity to be 72-76%, and performing treatment for 45 minutes; and then directly twisting the moisture regain leaves, placing the moisture regain leaves on a bamboo weaving operation surface during twisting operation, placing the bamboo weaving operation surface on the surface of a warm water pot through a support frame, keeping the temperature of the bamboo weaving operation surface at 55-58 ℃ through the warm water pot for twisting operation, air-drying the bamboo weaving operation surface at a set temperature of 15 ℃ by using low-temperature air-drying equipment after twisting is finished, spraying the prepared low-temperature extraction liquid to the surfaces of the air-dried leaves by using an atomizer when the water content of the tea leaves is 16%, spraying 15ml of low-temperature extraction liquid to each kilogram of the air-dried leaves, and drying the air-dried leaves sprayed with the low-temperature extraction liquid to a water content of less than 5% by using full fire to obtain the finished tea leaves with astringent taste removed.

In a comparative example, the tea leaves are obtained by processing the low-quality spring tea with the same raw materials according to the conventional sequence steps of water removing, rolling and drying, compared with the tea leaves, the finished tea leaves prepared in the embodiment have fresher tea fragrance, and after the tea leaves are brewed by hot water at 85-90 ℃, the bitterness of tea soup is obviously weaker than that of the tea leaves prepared in the comparative example, the tea leaves are easier to go down the throat, and the tea fragrance is fresher.

In example two:

the low-temperature extraction liquid of the white gourd powder and the alfalfa powder prepared by the method in the first embodiment and the white gourd fermentation liquid are selected as raw materials.

When tea processing is carried out, fresh summer tea leaves in the Henan Hengshan area are selected as raw materials, screening and impurity removal are carried out during processing, then the sun is naturally aired until the water content of the fresh tea leaves is reduced to 68-70%, then the fresh tea leaves are moved into a ventilation chamber, and spraying of low-temperature extraction liquid is completed according to the first embodiment mode, so that the fresh tea leaves can absorb part of the low-temperature extraction liquid to obtain secondary fresh tea leaves.

Performing steam de-enzyming when no water exists on the surfaces of fresh tea leaves for the second time, controlling the de-enzyming temperature to be 120 ℃ for processing for 50S to obtain de-enzymed leaves, flattening the de-enzymed leaves, and completing spraying of a wax gourd fermentation liquor diluent according to the first embodiment, wherein the mass ratio of the diluted wax gourd fermentation liquor diluent is 5%, the spraying amount is 12ml per kg of the de-enzymed leaves, the diluted wax gourd fermentation liquor is kept for 8h after being sprayed, so that the fermentation is continuous, then performing moisture regain processing for 45min, controlling the moisture regain temperature to be 28-32 ℃ and the moisture regain humidity to be 78-80%, then rolling the moisture regain leaves according to the first embodiment, controlling the temperature of a warm water pot to be 57-60 ℃, performing air drying at a low temperature environment with the set temperature of 12 ℃ by using low-temperature air drying equipment after rolling, performing spraying of a low-temperature extraction liquid according to the first embodiment when the water content of the tea leaves is 18%, controlling the spraying amount to be 12ml per kg of the low-temperature extraction liquid, and then drying the treated air-dried leaves by full fire until the water content is below 5 percent to obtain the finished product tea after removing the astringent taste.

In a comparative example, summer tea fresh leaves made of the same raw materials are processed according to the traditional sequential steps of enzyme deactivation, rolling and drying to obtain tea leaves, the tea leaves of the comparative example have better tea fragrance but poorer brewing effect, tea soup during tea brewing has obvious bitter and astringent taste, and particularly, under the condition that the tea brewing time exceeds 40S, the bitter is more obvious in deposition and difficult to fall into the throat; the finished tea prepared under the conditions of the examples is softer in taste after being brewed with hot water and has light fragrance, and under the brewing condition that the brewing time exceeds 30S, the bitter and astringent taste of the tea soup is obviously weaker than that of the tea prepared in the comparative example.

In example three:

the low-temperature extraction liquid of the white gourd powder and the alfalfa powder prepared by the method in the first embodiment and the white gourd fermentation liquid are selected as raw materials.

When tea processing is carried out, fresh autumn tea leaves in Sanqing mountain areas in Jiangxi are selected as raw materials, screening and impurity removal are carried out during processing, then the sun is naturally aired until the water content of the fresh tea leaves is reduced to 65-68%, then the fresh tea leaves are moved to a ventilation chamber, spraying of low-temperature extraction liquid is completed according to the first embodiment mode, and the fresh tea leaves can absorb part of the low-temperature extraction liquid to obtain secondary fresh tea leaves.

Performing steam de-enzyming when no water exists on the surfaces of fresh tea leaves for the second time, controlling the de-enzyming temperature to be 110 ℃ for 55S to obtain de-enzymed leaves, flattening the de-enzymed leaves, and completing spraying of a wax gourd fermentation liquor diluent according to the first embodiment, wherein the mass ratio of the diluted wax gourd fermentation liquor diluent is 4%, the spraying amount is 12ml per kg of the de-enzymed leaves, the diluted wax gourd fermentation liquor is kept for 7h after being sprayed, so that the fermentation is continuous, then performing moisture regain treatment for 50min, controlling the moisture regain temperature to be 32-35 ℃ and the moisture regain humidity to be 73-75%, then rolling the moisture regain leaves according to the first embodiment, controlling the temperature of a warm water pot to be 54-56 ℃, performing air drying at a low temperature environment with the set temperature of 12 ℃ by using low-temperature air drying equipment after rolling, performing spraying of low-temperature extraction liquid according to the first embodiment when the water content of the tea leaves is 18%, controlling the spraying amount to be 10ml per kg of low-temperature extraction liquid, and then drying the treated air-dried leaves by full fire until the water content is below 5 percent to obtain the finished product tea after removing the astringent taste.

In a comparative example, fresh autumn tea leaves with the same raw materials are processed according to the traditional sequence steps of enzyme deactivation, rolling and drying to obtain tea leaves, the tea leaves of the comparative example have tea fragrance superior to spring tea, the tea soup made by the method has light tea taste and less brewing times; compared with the tea prepared by the technical scheme of the comparative example, the finished tea prepared under the conditions of the embodiment is added with a layer of light fermentation fragrance and grass fragrance on the basis of the original tea fragrance, the brewing taste is superior to that of the tea of the comparative example, the tea taste is mellow compared with that of the tea of the comparative example, and the brewing frequency is 2-3 more than that of the tea of the comparative example on average.

Based on the embodiment and the comparative example corresponding to the embodiment, the finished tea prepared by the technical scheme of the application document is softer in taste than the tea prepared by a traditional three-step method, namely, the tea prepared by de-enzyming, rolling and drying, and bitter and astringent taste can be weakened in the treatment of middle and low-grade tea, summer tea and autumn tea, so that a large amount of middle and low-quality tea resources can be efficiently utilized, and the economic value is improved.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.