WO2021066679A1 - Procédé de traitement de thé vert - Google Patents

Procédé de traitement de thé vert Download PDF

Info

Publication number
WO2021066679A1
WO2021066679A1 PCT/RU2020/050179 RU2020050179W WO2021066679A1 WO 2021066679 A1 WO2021066679 A1 WO 2021066679A1 RU 2020050179 W RU2020050179 W RU 2020050179W WO 2021066679 A1 WO2021066679 A1 WO 2021066679A1
Authority
WO
WIPO (PCT)
Prior art keywords
drying
tea
green tea
tea leaves
temperature
Prior art date
Application number
PCT/RU2020/050179
Other languages
English (en)
Russian (ru)
Inventor
Игорь Васильевич ЛИСИНЕНКО
Ирина Николаевна ЛИСИНЕНКО
Original Assignee
Общество с ограниченной ответственностью "МАЙ"
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Общество с ограниченной ответственностью "МАЙ" filed Critical Общество с ограниченной ответственностью "МАЙ"
Publication of WO2021066679A1 publication Critical patent/WO2021066679A1/fr

Links

Classifications

    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23F—COFFEE; TEA; THEIR SUBSTITUTES; MANUFACTURE, PREPARATION, OR INFUSION THEREOF
    • A23F3/00—Tea; Tea substitutes; Preparations thereof
    • A23F3/06—Treating tea before extraction; Preparations produced thereby
    • A23F3/12—Rolling or shredding tea leaves

Definitions

  • the invention relates to methods for processing tea and can be used in the tea industry.
  • the withering operation makes the tea leaf more suitable for both manual and mechanical processing (the leaf becomes more "pliable").
  • Fixation means the processing of small portions of withered tea leaves during manual processing for several minutes (mainly from 7 to 10) at a temperature of 180 ° C and during mechanical processing at a temperature of about 250 ° C inside a rotating drum for 2-3 minutes. With such a short-term heating, enough moisture remains in the leaf to further subject it to the rolling operation, and at the same time, the temperature effect is sufficient for folding the vegetable protein contained in the tea leaf, which prevents the process of destruction of vitamins and microelements in the leaf (http: // tea.fmepokupka.ru/).
  • the rolling operation is aimed at shaping the sheet into the desired shape.
  • Final drying prevents the oxidation of polyphenols, thereby preserving the antioxidant properties of tea, in addition, drying determines the ability of tea for long-term storage and affects the most important organoleptic properties of tea - the aroma and color of the infusion, removing the herbal odor, developing the tea aroma.
  • the temperature at the initial stage of drying is low in order to ensure uniform heating of the tea brick. Since at the initial stage of drying, moisture intensively evaporates from the surface layers of the brick, this can lead to rapid drying, the appearance of cracks on the surface of the brick, to its deformation, while the middle of the brick remains wet.
  • the first stage of drying is carried out at a temperature of from 30 to 32 ° C.
  • tea humidity reaches 12.5-13.5%
  • tea briquettes are heated evenly throughout the entire volume, moisture transpiration in them increases and then the temperature is raised to 50-52 ° C, which speeds up the drying process.
  • the known method protects the temperature regime of convective drying, i.e. type of drying, in which the transfer of heat by the raw material occurs with the help of a drying agent / neutral gas, which simultaneously performs the function of a heat carrier and a moisture carrier / - a transport medium into which the removed moisture passes.
  • the disadvantages of convective drying are significant energy consumption of 1.8-3.0 kWh / kg, a decrease in the thermal conductivity of the product at the end of drying, which significantly lengthens the process, which, in turn, as already mentioned, negatively affects the quality of the product.
  • Convective drying in addition to the disadvantages noted, does not provide the possibility of long-term storage of products, being significantly inferior in this to infrared drying and freeze drying, as well as microwave drying.
  • drying using microwave radiation surpasses other known types of drying in a number of important indicators, as shown in the table given in the source (Ministry of Agriculture of the Russian Federation. FGOU VPO Irkutsk State Agricultural academy “Scientific-practical journal” Bulletin of IrGSKhA ", issue 36 September: Irkutsk, 2009.) D2.
  • pre-prepared whole tea leaves drying is preceded by keeping them in water at a temperature not exceeding room temperature, to prevent leaf damage, it is advisable to keep them at a temperature of 10 to 6 ° C
  • an oven with a capacity of 48 kilowatts and then the pressure in the oven is reduced up to 3 kPa.
  • the temperature in the upper layer of leaves reaches a temperature of about 160 ° C (after about 32.5 minutes)
  • the state of the leaves is monitored, if an insignificant part of the leaves is burnt, the oven turns off, the leaves are unloaded from the oven and cooled.
  • This method results in a tea that combines the flavor of roasted tea with the tangible herbal flavor of green tea.
  • the leaves may be further roasted by methods such as induction heating, conductive heating, and convection heating.
  • a method for processing green tea is known (RF patent N ° 2689694, published on May 28, 2019) D4, including inactivation of redox enzymes by thermal exposure to green tea leaves, followed by processing green tea leaves to a residual moisture content of 60-75%, rolling tea leaves, drying the tea leaves in a vacuum using an electromagnetic microwave field and sorting tea leaves leaf, characterized in that the drying of green tea leaves is carried out in three stages with a total duration of 85-157 minutes, on the first of which a layer of tea leaves with a moisture content of 60-75% is heated by an electromagnetic microwave field at a constant pressure in a drying chamber with values, selected from the range of values of 90-200 mm Hg, with a uniform rate of growth of the heating temperature, which is selected based on the need to reach the heating temperature values from the range of 40-60 ° C by the end of the first stage and taking into account the duration of the first stage, at the second stage of drying, increase the pressure in the drying chamber is up to values of 200-500 mm Hg, and
  • the method presented in D4 is quite complex and contains a multi-stage drying stage, which leads to a deterioration in the quality of the tea due to excessive heating of the raw material.
  • the information source D4 is selected as the closest analogue to the claimed invention.
  • the problem to be solved by the claimed invention is to develop a method for processing green tea, which will eliminate the disadvantages of the prior art.
  • the technical result to be achieved by the present invention consists in simplifying the technology of drying green tea, ensuring uniform heating of each batch of tea loaded into the drying chamber, preventing caramelization of sugars at the initial stages of the drying regime, increasing the extract of green tea infusion and improving its organoleptic properties.
  • the specified technical result is achieved due to the fact that the method for processing green tea, including the inactivation of redox enzymes by thermal exposure to green tea leaves, followed by processing green tea leaves to a residual moisture content of 60-75%, rolling the tea leaf, drying the tea leaf in vacuum using an electromagnetic microwave field to a residual moisture content of less than 10%, and sorting the tea leaf, characterized in that drying of green tea leaves is carried out in two stages, in the first of which a layer of tea leaves is heated for 8-12 minutes, no more than 10 cm in height, with a humidity of 60-75% by an electromagnetic microwave field, at constant pressure in the drying chamber with values , selected from the range of 40-80 kPa, with a uniform heating temperature growth rate of 3-4 ° C / s, which is selected based on the need to reach the heating temperature values from the range of 70-85 ° C by the end of the first stage and taking into account the duration of the first stage, at the second stage of drying, pulsed heating is applied in the range
  • Tea for the purposes of the present invention means the leaf material Camellia sinensis var. sinensis or Camellia sinensis var. assamica
  • Leaf tea means plant material obtained from a tea plant that has not been infused.
  • Microwave radiation or high-intensity microwave radiation is used for non-contact heating of bodies.
  • the product heats up due to the presence of dipole molecules in it, at one end of which there is a positive electric charge, and at the other - a negative one.
  • dipole molecules line up along its lines of force.
  • a change in the direction of the field entails a change in the direction of the molecules.
  • Water molecules are dipoles, respectively, at an oscillation frequency of 1000 MHz, the electric field 2,000,000,000 times per second changes its direction and with the same frequency the direction of water molecules changes in it. Due to the resulting friction of the molecules, the product is heated and the liquid evaporates.
  • Microwaves work only in a relatively small surface layer of the product, penetrating inside to a depth of several centimeters, heating occurs due to the heating of the surface layer by microwaves and the subsequent penetration of heat into the depth of the heated product due to its thermal conductivity.
  • High-voltage vacuum devices - magnetrons are used as sources of the electromagnetic microwave field. Magnetrons can operate at various frequencies from 0.5 to 100 GHz, with powers from several W to tens of kW in continuous mode, and from 10 W to 5 MW in pulsed mode with pulse durations mainly from fractions to tens of microseconds.
  • the interference of waves amplifies the waves that arrived in phase, such waves will warm up the area they hit, and those that arrived in antiphase will extinguish each other.
  • One of the ways to solve the problem of uniform heating of a batch of a product in a drying oven is to ensure the arrival of microwave radiation to a selected area of the processed product from different sources by switching on sources of an electromagnetic microwave field in a pulsed mode, and the radiation of each of these sources affects the selected plot from different directions.
  • inverter power systems widely used in air conditioners, that allow their power to be varied smoothly.
  • inverter power systems also make it possible to smoothly change the power of the radiation source (magnetron), instead of turning it off at specified time intervals.
  • electromagnetic microwave field When processing green tea leaves with an electromagnetic microwave field, it undergoes profound changes, including significantly changing its dielectric properties that affect the kinetics of microwave heating. This creates certain difficulties in maintaining optimal processing conditions that provide an adequate response to changes in product properties throughout the technological cycle.
  • microwave ovens for heating dielectrics
  • unevenness of heating associated with a drop in specific power, inhomogeneity of composition and moisture content, as a rule, with an irregular shape of the product.
  • the most effective technology for drying green tea in a microwave oven is to create a technology based on experimental data obtained during drying a batch of green tea in a microwave oven.
  • the geometry of the oven and the location of microwave sources (magnetrons) in it are designed to ensure the uniformity of the effect of microwave radiation on the product being dried.
  • the batches of green tea loaded into the drying oven consisted of layers of green tea leaves that had passed the withering stage, forming rectangular horizontally elongated stacks up to 10 cm high.
  • the objects in the experiments were a green tea leaf Camellia sinensis var. Sinensis or Camellia sinensis var. Assamica.
  • the claimed method is carried out as follows: freshly harvested tea leaves were withered in the traditional way - storage for several hours, possibly up to 24 hours. At the same time, tea leaves lost moisture at a rate depending on the temperature and humidity of the external environment and the amount of surface moisture. In the process of withering, about 15 percent of moisture was lost: from 70 to 85% in a fresh leaf and up to 55-70% in tea leaves that had passed the stage of withering. Fermentation in the cut tea leaves begins immediately after the cut. So green tea, which, unlike black tea, is considered unfermented, actually goes through fermentation, albeit for a very short period of time.
  • Fixation inactivation of redox enzymes is performed by heat exposure of green tea leaves for several minutes, followed by drying of the leaves to a residual moisture content of 60-75%.
  • Drying of tea leaves in vacuum is carried out using an electromagnetic microwave field, so that drying of green tea leaves is carried out in two stages.
  • a layer of tea leaves no more than 10 cm in height, with a moisture content of 60-75%, is heated for 8-12 minutes by an electromagnetic microwave field at a constant pressure in a drying chamber with values selected from the range of 40-80 kPa, with a uniform the heating temperature growth rate of 3-4 ° C / s, which is selected based on the need to reach the heating temperature values from the range of 70-85 ° C by the end of the first stage and taking into account the duration of the first stage.
  • pulsed heating is applied in the range of 35-45 ° C by means of a microwave field, when the pressure in the drying chamber is reduced to 15-4 kPa until the residual moisture is reached, after which the vacuum pump is turned off and atmospheric pressure is restored in the chamber. lowering the temperature, which helps to stabilize the entire processing of green tea. Drying by pulse heating is carried out until the residual moisture is less than 10%.
  • the duration and intensity of the processing steps depend both on the properties of the green tea leaves and the parameters of the equipment, as well as on maintaining the possibility of vaporization in the tea leaves, which is necessary for drying them.
  • Exposure to green tea leaves by microwave radiation is carried out under vacuum conditions (the pressure is changed using a pump) at a pressure value in the range of 40-80 kPa. This eliminates mold contamination, reduces the intensity of the oxidation process of tea, tea raw materials and reduces the rate of division of bacteria.
  • the choice of specific pressure values is determined by the moisture content of the green tea leaf before drying.
  • Pasteurization includes a single heating to a temperature of 60 ° C with further exposure at this temperature for 60 minutes or heating to 70-80 ° C with exposure for 30 minutes or heating to 98 ° C and above with exposure for several seconds.
  • Sterilization is carried out by various chemical and physical methods, the latter include exposure to ultraviolet radiation, high-frequency currents, ultrasonic vibrations, radioactive radiation, infrared rays, etc., as well as exposure to high temperatures on sterilized objects (heat sterilization).
  • heat sterilization As a result of pasteurization, vegetative forms of microorganisms die, but the spores survive and, when favorable conditions occur, intensive reproduction begins.
  • the use of high temperature during sterilization for a long time helps to completely destroy not only the microorganisms themselves, but also their spores. But prolonged exposure to high temperatures destroys the substances that give the taste and aroma of tea, as well as the vitamins it contains.
  • the temperature exposure regime should ensure the destruction of microbes that form mold on tea in the temperature range of their growth and, in addition, ensure the rapid passage of temperatures at which the growth rate constant is maximum.
  • the curve of the dependence of the growth rate on temperature for each organism has its own, while the Q10 law applies: with an increase in temperature by 10 ° C, the reaction rate increases by 2-4 times. Growth slows down significantly when crossing the optimum temperature.
  • the task of disinfection due to heating is the rapid passage of temperature values at which the growth rate of microorganisms (the number of generations per hour), and, accordingly, the intensity of reproduction, is maximum and the transition to those temperatures at which the rate of death of microorganisms is maximum.
  • the temperature ranges at which green tea undergoes thermal treatment in an evacuated drying chamber equipped with microwave radiation sources (usually magnetrons) should be selected based on the above considerations.
  • the value of the pressure decrease is selected based on the synchronization of the temperature values as it decreases after switching off the sources of the electromagnetic microwave field with those pressure values at which the current values of the temperature of green tea leaves provide the process of vaporization.
  • thermochemical processes occur, as a result of which the specific aroma, color and taste of the finished tea are finally formed.
  • the taste softens, the infusion intensifies, its color, the destruction of substances (chlorophyll and others) that negatively affect the taste characteristics of tea.
  • the improvement in aroma is due to an increase in the interaction of phenolic compounds with amino acids and other substances that affect the formation of volatile aldehydes, which have a pleasant smell.
  • a high content of L-theanine is characteristic of young leaves; during the processing of tea leaves, the amount of this amino acid decreases during fermentation and a greater amount is released into the solution depending on the duration of drying at a low temperature - the maximum content is reached after drying at a temperature of 40-55 ° C within 7, 0-8, 5 hours.
  • the concentration of L-theanine after processing green tea leaves with an electromagnetic microwave field in a low vacuum for 3-10 minutes at temperatures close to 90 ° C and followed by a decrease in pressure and temperature-pressure to values close to the boundary values of the average vacuum, and temperatures to room values (temperature in the workshop, etc.), is comparable to that obtained as a result of drying at a temperature of 40-55 ° C for 7, 0-8, 5 hours.
  • Carrying out the initial stage of drying with the operation of microwave sources in the maximum power mode allows not to carry out the fixation stage, thereby reducing the total processing time of green tea leaves from the moment they are cut to packaging of finished products intended for delivery to the market.
  • the claimed method makes it possible to obtain tea with a microbial load several times lower than that allowed by the standards in force in the tea industry and with improved organoleptic properties.
  • the claimed method can be carried out using known devices for drying ovens with microwave radiation, which confirms its industrial applicability.
  • the magnetrons were switched off and on in a pulsed mode, based on the possibility of uniform heating of all sections of the processed tea layer.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Polymers & Plastics (AREA)
  • Tea And Coffee (AREA)

Abstract

L'invention se rapporte au domaine de l'industrie du thé. L'invention consiste à inactiver les ferments oxydo-réducteurs par une action thermique sur les feuilles de thé vert, puis à traiter les feuilles de thé vert jusqu'à atteindre une humidité résiduelle de 60-75%. Les feuilles de thé sont ensuite écrasées. Le séchage des feuilles de thé se fait en deux étapes, et les feuilles de thé sont triées. Lors de la première étape, on chauffe pendant 8-12 minutes une strate de feuilles de thé d'une hauteur ne dépassant pas 10 cm et une humidité de 60-75% en utilisant un champ électromagnétique à micro-ondes, ceci à une pression constante dans une chambre de séchage à des valeurs choisies dans une plage de 40- 80 kPa, et à une vitesse constante d'augmentation de la température de chauffage de 3-4°С/s. La vitesse est choisie selon la nécessité d'atteindre à la fin de la première étape des valeurs de température de chauffage dans une plage de 70-85°С et en tenant compte de la durée de la première étape. Lors de la seconde étape de séchage, on utilise un chauffage par impulsions dans une plage de 35-45°С en utilisant un champ électromagnétique à micro-ondes, ceci en abaissant la pression dans la chambre de séchage à une valeur de 15-4 kPa jusqu'à atteindre une humidité résiduelle de moins de 10%. La pompe à vide est ensuite arrêtée et on rétablit la pression atmosphérique dans la chambre. L'invention permet de simplifier la technique de séchage de thé vert, d'assurer un chauffage uniforme de chaque partie du thé chargée dans la chambre de séchage, d'empêcher la caramélisation des sucres lors des étapes initiales du mode de séchage, d'augmenter les capacités d'extraction de l'infusion de thé vert, et d'améliorer ses propriétés organoleptiques.
PCT/RU2020/050179 2019-10-03 2020-08-04 Procédé de traitement de thé vert WO2021066679A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
RU2019131136A RU2727671C1 (ru) 2019-10-03 2019-10-03 Способ обработки зеленого чая
RU2019131136 2019-10-03

Publications (1)

Publication Number Publication Date
WO2021066679A1 true WO2021066679A1 (fr) 2021-04-08

Family

ID=71741359

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/RU2020/050179 WO2021066679A1 (fr) 2019-10-03 2020-08-04 Procédé de traitement de thé vert

Country Status (2)

Country Link
RU (1) RU2727671C1 (fr)
WO (1) WO2021066679A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112293513A (zh) * 2020-11-18 2021-02-02 湖南省求喜茶业有限公司 紧压绿茶的制备方法、绿茶

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2318392C2 (ru) * 2002-06-28 2008-03-10 Унилевер Нв Производство чая
RU2683474C1 (ru) * 2018-03-21 2019-03-28 Общество с ограниченной ответственностью "МАЙ" Способ обработки сухого черного чая, чайного сырья
RU2689694C1 (ru) * 2018-03-21 2019-05-28 Общество с ограниченной ответственностью "МАЙ" Способ обработки зеленого чая

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB201005072D0 (en) * 2010-03-26 2010-05-12 Givaudan Sa Process

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2318392C2 (ru) * 2002-06-28 2008-03-10 Унилевер Нв Производство чая
RU2683474C1 (ru) * 2018-03-21 2019-03-28 Общество с ограниченной ответственностью "МАЙ" Способ обработки сухого черного чая, чайного сырья
RU2689694C1 (ru) * 2018-03-21 2019-05-28 Общество с ограниченной ответственностью "МАЙ" Способ обработки зеленого чая

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112293513A (zh) * 2020-11-18 2021-02-02 湖南省求喜茶业有限公司 紧压绿茶的制备方法、绿茶

Also Published As

Publication number Publication date
RU2727671C1 (ru) 2020-07-22

Similar Documents

Publication Publication Date Title
Jaeger et al. The Maillard reaction and its control during food processing. The potential of emerging technologies
Bhatt et al. Microwaves and radiowaves: in food processing and preservation
JPH08308487A (ja) 新鮮果実および野菜の保存方法
KR102062328B1 (ko) 낱장 매운 김치의 제조방법
JP2019170356A (ja) 爽快な青葉の香りを有する緑茶の製造方法
Basaran et al. Microwave irradiation of hazelnuts for the control of aflatoxin producing Aspergillus parasiticus
RU2689694C1 (ru) Способ обработки зеленого чая
RU2727671C1 (ru) Способ обработки зеленого чая
CN107372794A (zh) 一种水果的干燥方法
JP4846838B2 (ja) 杜仲葉緑色乾燥品の製造方法
WO2021066683A1 (fr) Procédé de traitement de thé noir sec
AU2011231541A1 (en) Process for green tea manufacture with microwave roasting
RU2683474C1 (ru) Способ обработки сухого черного чая, чайного сырья
CN108077462B (zh) 一种降低乌龙茶中高效氯氟氰菊酯和氰戊菊酯残留的方法
CN107568558B (zh) 冻干食品的蒸汽巴氏灭菌方法
JPS63169933A (ja) 粉茶の製法
Dewan et al. Radio‐Frequency Technology in Food Processing
CN105979787B (zh) 用于制作具有增强的风味的绿茶的方法
KR20190043239A (ko) 야콘 장아찌의 제조방법
CN112401104A (zh) 一种橙碳量子点结合微波-射频处理特色豆制品控菌提质的方法
Kour et al. Microwave and Radio frequency processing
WO2013035832A1 (fr) Procédé de production d'un produit vert déshydraté à base de feuilles d'eucommia
JP5323003B2 (ja) 杜仲葉緑色乾燥品の製造方法
CN112586683A (zh) 烧鸡的加工工艺
JP3084358B2 (ja) 杜仲葉茶葉及びその製造方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 20870458

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 20870458

Country of ref document: EP

Kind code of ref document: A1