Processing technology for improving quality of tea leaves

Abstract

The invention relates to a processing technology for improving tea quality. Precise control is performed from the beginning of tea leaf picking, rapid transfer of the unmanned aerial vehicle is utilized, damage, oxidation and other conditions of tea leaves are avoided, the consistency of raw materials is improved, through cooperation of the solar heat pump system and the near-infrared spectrometer, the tea leaf withering time is effectively shortened, the tea leaf water content is controlled, and the tea leaf withering quality is improved through combined treatment of microwaves and hot air. Uniform fixation of the tea leaves is realized, the fixation effect is improved, crushed materials of tea leaf cells are accurately controlled through staged pressurized rolling of an air pressure rolling machine, uniform seepage of tea leaf juice is ensured, and in the fermentation process, the temperature and humidity are accurately regulated and controlled, the fermentation time is controlled, and the generation condition of aroma substances is monitored by using an electronic nose; the content of components such as theaflavin is increased, and the retention rate of aroma components is increased by utilizing far infrared drying and vacuum freeze drying technologies. According to the technology, through multi-link accurate control, the quality of the tea leaves is effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tea processing, in particular to a processing technology for improving the quality of tea. BACKGROUND

[0002] Tea is a traditional beverage in China. The existing tea production process generally includes picking, withering, fixation, rolling and drying. If the picking process is not properly controlled, different grades of tea and old leaf impurities may be mixed together, the tea may be damaged, and the tea may be squeezed and oxidized, all of which may affect the quality of the tea. In the withering process, natural withering is traditionally used, which is greatly affected by the weather, resulting in uneven withering. If the temperature and time are not accurately controlled in the fixation process, fixation may be insufficient or excessive. The rolling process has difficulty in controlling the cell breakage rate and juice exudation amount, and improper control may affect the fermentation of the tea in the later stage. Therefore, in order to improve the quality of the tea, each process needs to be accurately controlled, and the current intelligent instruments can be used to accurately control the parameters of each process. SUMMARY

[0003] In view of the problems in the prior art, the present application discloses a processing technology for improving the quality of tea, including the following steps: Step one: picking tea buds and leaves with one bud and two leaves by manual accurate selection to avoid damage to the buds and leaves, to disperse the transportation and to reduce the squeezing and oxidation of the buds and leaves; Step two: removing impurities from the picked buds and leaves by electrostatic dust removal and airflow separation; Step three: placing the impurity-removed buds and leaves in a withering tank, maintaining the environmental temperature at 25-30 DEG C and the humidity at 55%-65% by a solar heat pump system, detecting the moisture content of the leaves every 10 minutes until the moisture content of the leaves is reduced to 60%-65%, and obtaining withered leaves. Step four: pre-treating the withered leaves by microwave for 30 seconds to quickly inactivate enzyme activity, and then dehydrating the withered leaves by hot air with the leaf temperature controlled by infrared temperature measurement to be not greater than 80 DEG C for 5 minutes, and obtaining fixed leaves; Step five: placing the fixed leaves in a pressure rolling machine to perform staged pressure rolling for 20-35 minutes, and obtaining rolled leaves; Step six: placing the rolled leaves in a fermentation bin to control the temperature at 25-28 DEG C and the humidity at 90%, and performing fermentation, and automatically terminating the fermentation when the change in aroma substances is detected by an electronic nose to reach a set value, and obtaining fermented leaves; Step seven: drying the fermented leaves by far infrared drying to a moisture content of 10%, and then vacuum freeze-drying the fermented leaves to a moisture content of not greater than 5%, and obtaining finished tea leaves.

[0004] As a preferred embodiment of the present application, the dispersed transportation in step one uses an unmanned aerial vehicle to directly transport the tea to a processing workshop.

[0005] As a preferred scheme of the present application, the step three selects the near-infrared spectrometer to detect the moisture content of the leaves.

[0006] As a preferred scheme of the present application, the step four selects the microwave frequency of 2450MHz, and the hot air temperature of 120℃.

[0007] As a preferred scheme of the present application, the step five is divided into four stages, i.e., light pressure, medium pressure, heavy pressure and loose pressure, the light pressure stage is controlled at 50-80kPa for 4-8 minutes, the medium pressure stage is controlled at 100-150kPa for 9-14 minutes, the heavy pressure stage is controlled at 180-220kPa for 4-8 minutes, and the loose pressure stage is controlled at 30-50kPa for 3-5 minutes.

[0008] As a preferred scheme of the present application, the step six is the aroma substance of theaflavin.

[0009] As a preferred scheme of the present application, the step seven is the temperature of the far-infrared drying of 80℃, and the temperature of the vacuum freeze drying of -30℃.

[0010] The present application has the following advantages: the present application precisely controls from the picking of the tea leaves, uses the rapid transfer of the unmanned aerial vehicle to avoid the damage and oxidation of the tea leaves, improves the consistency of the raw materials, effectively shortens the withering time of the tea leaves by the cooperation of the solar heat pump system and the near-infrared spectrometer, controls the moisture content of the tea leaves, realizes the uniform fixation of the tea leaves by the joint treatment of the microwave and the hot air, improves the fixation effect, precisely controls the broken material of the tea leaf cells by the stage-by-stage pressure rolling of the air pressure rolling machine, ensures the uniform exudation of the tea leaf juice, controls the fermentation time by the precise regulation of the temperature and humidity during the fermentation, improves the content of theaflavin and other components by the monitoring of the generation of the aroma substance by the electronic nose, and improves the retention rate of the aroma components by the far-infrared drying and the vacuum freeze drying technology. The present application improves the quality of the tea leaves by the precise control of the multiple links. DETAILED DESCRIPTION

[0011] Embodiment 1

[0012] The present application is a processing technology for improving the quality of tea leaves, which comprises the following steps: Step one, the tea leaves of one bud and two leaves are precisely selected by the manual picking to avoid the damage of the bud and leaf, and the unmanned aerial vehicle is used for the dispersed transportation to directly transport to the processing workshop, thereby improving the transportation efficiency and reducing the extrusion and oxidation of the bud and leaf; Step two, the picked bud and leaf are removed by the electrostatic dust removal and air flow sorting; Step three, the impurity-removed bud leaves are laid in a withering tank, the ambient temperature is maintained at 25 DEG C by a solar heat pump system, the humidity is 55%, the leaf moisture content is detected every 10 minutes by a near-infrared spectrometer until the leaf moisture content is reduced to 60%, and withered leaves are obtained. Step four, the withered leaves are pretreated by microwaves with a frequency of 2450 MHz for 30 seconds to quickly inactivate enzyme activity, and then assisted by hot air at 120 DEG C for dehydration, the leaf temperature is controlled to be no greater than 80 DEG C by infrared temperature measurement, and the dehydration is performed for 5 minutes, and fixed-leaf tea is obtained. Step five, the fixed-leaf tea is put into a pneumatic rolling machine to perform staged pressurized rolling, which is specifically divided into four stages of light pressure, medium pressure, heavy pressure and loose pressure, the pressure is controlled at 50 kPa for 8 minutes in the light pressure stage, the pressure is controlled at 100 kPa for 14 minutes in the medium pressure stage, the pressure is controlled at 180 kPa for 8 minutes in the heavy pressure stage, and the pressure is controlled at 30 kPa for 5 minutes in the loose pressure stage, and the total rolling time is 35 minutes, and rolled leaves are obtained. Step six, the rolled leaves are put into a fermentation bin, the temperature of the fermentation bin is controlled at 25 DEG C, the humidity is 90%, fermentation is performed, the change of aroma substances such as theaflavins is monitored by an electronic nose, and the fermentation is automatically terminated after reaching the set value, and fermented leaves are obtained. Step seven, the fermented leaves are dried by a far-infrared drying device at a temperature of 80 DEG C until the moisture content is 10%, and then dried by vacuum freeze drying at a temperature of-30 DEG C until the moisture content is no greater than 5%, and finished tea leaves are obtained.

[0013] Example 2

[0014] The processing technology for improving the quality of tea leaves provided by the application comprises the following steps: Step one, one-bud-two-leaf tea leaves are manually and accurately selected for picking to avoid damage to the bud leaves, and unmanned aerial vehicles are used for dispersed transportation to directly transport the tea leaves to a processing workshop, thereby improving the transportation efficiency and reducing the extrusion and oxidation of the bud leaves. Step two, the picked bud leaves are subjected to electrostatic dust removal and airflow separation to remove impurities. Step three, the impurity-removed bud leaves are laid in a withering tank, the ambient temperature is maintained at 30 DEG C by a solar heat pump system, the humidity is 65%, the leaf moisture content is detected every 10 minutes by a near-infrared spectrometer until the leaf moisture content is reduced to 65%, and withered leaves are obtained. Step four, the withered leaves are pretreated by microwaves with a frequency of 2450 MHz for 30 seconds to quickly inactivate enzyme activity, and then assisted by hot air at 120 DEG C for dehydration, the leaf temperature is controlled to be no greater than 80 DEG C by infrared temperature measurement, and the dehydration is performed for 5 minutes, and fixed-leaf tea is obtained. Step five, put the killed leaves into the air pressure rolling machine to carry out staged pressure rolling, which is specifically divided into four stages of light pressure, medium pressure, heavy pressure and loose pressure, the pressure is controlled at 80kPa in the light pressure stage, the time is 4 minutes, the pressure is controlled at 150kPa in the medium pressure stage, the time is 9 minutes, the pressure is controlled at 220kPa in the heavy pressure stage, the time is 4 minutes, the pressure is controlled at 50kPa in the loose pressure stage, the time is 3 minutes, and the total rolling time is 20 minutes, to obtain rolled leaves; Step six, put the rolled leaves into the fermentation bin, control the temperature of the fermentation bin to be 28℃ and the humidity to be 90%, carry out fermentation, monitor the change of teaflavin and other aroma substances through the electronic nose, automatically terminate the fermentation after reaching the set value, and obtain fermented leaves; Step seven, dry the fermented leaves through the far infrared drying equipment at a temperature of 80℃ until the moisture content is 10%, and then dry through vacuum freeze drying at a temperature of-30℃ until the moisture content is not higher than 5%, to obtain finished tea leaves.

[0015] Example 3

[0016] The processing technology for improving the quality of tea leaves provided by the application comprises the following steps: Step one, pick one bud and two leaves of tea buds and leaves by manual accurate selection to avoid bud and leaf damage, and use unmanned aerial vehicles to transport them in a scattered manner to the processing workshop, thereby improving the transportation efficiency and reducing the extrusion and oxidation of the buds and leaves; Step two, remove impurities from the picked back buds and leaves through electrostatic dust removal and airflow separation; Step three, place the impurity-removed buds and leaves in the withering tank, maintain the environmental temperature at 28℃ and the humidity at 60% through the solar heat pump system, detect the moisture content of the leaves every 10 minutes through the near-infrared spectrometer, and until the moisture content of the leaves is reduced to 63%, to obtain withered leaves. Step four, pretreat the withered leaves through microwaves with a frequency of 2450MHz for 30 seconds to quickly inactivate enzyme activity, and then assist in dehydration through hot air at 120℃, control the leaf temperature to be not higher than 80℃ through infrared temperature measurement, and dehydrate for 5 minutes, to obtain killed leaves; Step five, put the killed leaves into the air pressure rolling machine to carry out staged pressure rolling, which is specifically divided into four stages of light pressure, medium pressure, heavy pressure and loose pressure, the pressure is controlled at 65kPa in the light pressure stage, the time is 6 minutes, the pressure is controlled at 130kPa in the medium pressure stage, the time is 12 minutes, the pressure is controlled at 200kPa in the heavy pressure stage, the time is 6 minutes, the pressure is controlled at 40kPa in the loose pressure stage, the time is 4 minutes, and the total rolling time is 28 minutes, to obtain rolled leaves; Step six, put the rolled leaves into the fermentation bin, control the temperature of the fermentation bin to be 27℃ and the humidity to be 90%, carry out fermentation, monitor the change of teaflavin and other aroma substances through the electronic nose, automatically terminate the fermentation after reaching the set value, and obtain fermented leaves; Step seven, the fermented leaves are dried to a moisture content of 10% at a temperature of 80°C by far infrared drying equipment, and then dried to a moisture content of not higher than 5% at a temperature of -30°C by vacuum freeze drying, to obtain finished tea leaves.

[0017] Components not described in detail herein are prior art.

[0018] Although the specific embodiments of the present application have been described in detail above, the present application is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present application, and modifications or changes without creative labor are still within the protection scope of the present application.

Claims

1. A processing technology for improving the quality of tea, characterized in that: The steps are as follows: Step 1: Manually select tea buds with one bud and two leaves for picking to avoid damage to the buds and leaves, disperse the transportation, and reduce the squeezing and oxidation of the buds and leaves; Step 2: The picked buds and leaves are sorted by electrostatic dust removal and air flow to remove impurities; Step 3: Place the buds and leaves after removing impurities in a withering trough, maintain the ambient temperature at 25-30°C and the humidity at 55%-65% through a solar heat pump system, and check the moisture content of the leaves every 10 minutes until the moisture content of the leaves drops to 60%-65% to obtain withered leaves. Step 4: pre-treat the withered leaves with microwaves for 30 seconds to quickly inactivate enzyme activity, then dehydrate with hot air, control the leaf temperature to no more than 80°C by infrared temperature measurement, and dehydrate for 5 minutes to obtain withered leaves; Step 5: Place the fixed leaves into a pressure rolling machine and perform pressure rolling in stages for 20-35 minutes to obtain rolled leaves; Step 6: Place the rolled leaves into a fermentation chamber, control the temperature of the fermentation chamber at 25-28°C and the humidity at 90%, and ferment. Monitor the changes in aroma substances using an electronic nose, and automatically terminate the fermentation when the set value is reached to obtain fermented leaves. Step 7: Dry the fermented leaves by far infrared drying to a moisture content of 10%, and then freeze-dry them by vacuum drying to a moisture content of no more than 5% to obtain finished tea leaves.

2. A processing technology for improving tea quality according to claim 1, characterized in that: The decentralized transportation in step one is carried out by drone and directly delivered to the processing workshop.

3. A processing technology for improving tea quality according to claim 1, characterized in that: Step three: Use a near-infrared spectrometer to detect the moisture content of the leaves.

4. The process for improving tea quality according to claim 1, wherein: The microwave frequency selected in step 4 is 2450 MHz and the hot air temperature is 120°C.

5. The process for improving tea quality according to claim 1, wherein: The staged pressurization and kneading process described in step 5 is specifically divided into four stages: light pressure, medium pressure, heavy pressure, and loose pressure. The pressure in the light pressure stage is controlled at 50-80 kPa for 4-8 minutes, the pressure in the medium pressure stage is controlled at 100-150 kPa for 9-14 minutes, the pressure in the heavy pressure stage is controlled at 180-220 kPa for 4-8 minutes, and the pressure in the loose pressure stage is controlled at 30-50 kPa for 3-5 minutes.

6. The process for improving tea quality according to claim 1, wherein: The aroma substance in step six is ​​theaflavin.

7. The process for improving tea quality according to claim 1, wherein: The temperature of far-infrared drying in step 7 is 80°C, and the temperature of vacuum freeze drying is -30°C.