Method of producing tea

Abstract

FIELD: food industry.SUBSTANCE: raw material used is dried, and tea stalks are used as the raw material. Tea stems pre-packed in flexible, airtight containers are subjected to high hydrostatic pressure in the range of 100-300 MPa for 5-15 min at a liquid phase temperature of 20-35 °C. The stalks are removed from the containers and treated with an aqueous solution comprising 0.2 wt.% succinic acid salt and 0.1 wt.% monosodium glutamate, in a volume of 300-500 ml per 1 kg of raw material with uniform distribution of the solution over the surface of the stalks and holding for 30-60 minutes at a temperature of 25-30 °C. Then fermentation is carried out in an atmosphere of carbon dioxide at a temperature of 30-35 °C and humidity 60-70% for 8-12 hours. Drying is carried out at a temperature of up to 45 °C with residual moisture content of no more than 6%, followed by separation and aging.EFFECT: making a drink with a soft, rich taste with fruity and spicy notes.1 cl, 1 tbl, 3 ex

Description

[0001] Technical field.

[0002] The invention relates to the food industry, namely to methods for producing teas with increased antioxidant activity, obtained by improving the technology for processing tea raw materials.

[0003] The tea industry is rapidly transforming from a raw material industry into an industry of specialized, consumer-focused products. Modern consumers are interested in natural, healthy beverages that are part of a modern, healthy lifestyle. Tea is one such beverage. According to recent research, the antioxidant activity of tea made from the leaves, stems, and petioles of Camellia sinensis has scientifically proven physiological and biochemical effects aimed at protecting the body from oxidative stress and its consequences. Therefore, special attention is being paid to the production of products rich in antioxidants and high in gamma-aminobutyric acid (GABA).

[0004] Prior art.

[0005] A known method of processing tea leaves involves withering the tea leaves to a moisture content of 50-70%, twisting and fermentation in two stages - the first under vacuum at 15-30°C for 1-12 hours, the second (aerobic) - for 0.5-12 hours and drying to a moisture content of 7%. This method allows one to obtain black tea with a fairly high content of GABA [I].

[0006] The disadvantage of this method is the insufficient specification of the parameters (wide ranges of anaerobic (1-12 h) and aerobic (0.5-12 h) fermentation times, as well as temperatures (15-30°C) are given, without specifying optimal values ​​or justifying their selection, the lack of information on humidity control during the fermentation process, the drying conditions are described fragmentarily, which is insufficient for reliable reproduction of the industrial process.

[0007] The closest in technical essence and achieved result to the claimed invention is a method for preparing tea with an increased content of amino acids, including collecting the source material for the production of tea, including stems and leaves, physically separating the stem material from the leaf material in order to obtain a tea plant with a large number of stems, processing the source material using at least one of the traditional methods of processing tea, including withering, maceration, grinding, steaming, fermentation, drying [II].

[0008] The disadvantage of this method is that it does not include preliminary stimulation of antioxidant activity, which ensures the opening of cellular structures and increases the efficiency of enzymatic conversion. Furthermore, the fermentation conditions are general and not optimized for temperature and humidity, and drying at elevated temperatures can reduce catechin levels.

[0009] The objective of this invention is to develop a method for producing tea using tea stalks, which can improve the functional properties of tea.

[0010] The technical result is an increase in the antioxidant activity and the content of gamma-aminobutyric acid in the target product.

[0011] Brief summary of the invention.

[0012] The technical result achieved is that in the method of producing tea, which includes withering of raw materials, fermentation and drying, tea stalks are used as raw materials, and after withering, the tea stalks, pre-packed in flexible sealed containers, are exposed to high hydrostatic pressure in the range of 100-300 MPa for 5-15 minutes at a liquid phase temperature of 20-35 °C, then the stalks are removed from the containers and treated with an aqueous solution containing 0.2 wt. % of succinic acid salt and 0.1 wt.% of monosodium glutamic acid salt, in a volume of 300-500 ml per 1 kg of raw material with uniform distribution of the solution over the surface of the petioles and holding for 30-60 minutes at a temperature of 25-30 ° C, after which fermentation is carried out in an atmosphere of carbon dioxide at a temperature of 30-35 ° C and humidity of 60-70% for 8-12 hours, and drying is carried out at a temperature of up to 45 ° C to a residual moisture content of no more than 6%, followed by separation and aging.

[0013] The term "tea petiole" refers to the structural part of the tea plant that connects the leaf blade to the stem, although the petiole and stem are considered distinct parts of the tea plant. In traditional tea production processes, petioles are separated and discarded as waste, despite containing beneficial substances such as L-theanine, phenolic compounds, and fiber. They also contain significant amounts of glutamic acid, a precursor to GABA.

[0014] Implementation of the invention.

[0015] The method is implemented as follows. Pre-sifted tea stalks are withered on trays or drums at a temperature of at least 26°C for 10-12 hours to remove excess moisture (by 30-40%) and initiate enzymatic processes. The raw materials are hermetically sealed in HHP-compatible bags (durable polyamide / polyethylene bags that are resistant to high pressure), from which air is evacuated (vacuum), and hermetically sealed. The bags are loaded into a Laboratory HHP 6L hydrostatic chamber filled with water, which is then sealed. The pump then supplies water to a closed system at a pressure of 100-300 MPa, maintaining it for 5-15 minutes at a liquid temperature of 20-35°C (otherwise, undesirable enzymes will be activated). When compressed, the water transfers isostatic pressure (equal in all directions) through the flexible wall of the package. The chamber is then released, and the bags containing the tea stems are removed.The raw material is then treated by spraying with a uniform distribution on the surface of the raw material of an aqueous solution containing 0.2 wt.% succinic acid salt (sodium succinate (food additive E363)) and 0.1 wt.% monosodium salt of glutamic acid, in an amount of 300-500 ml per 1 kg of petioles and holding for 30-60 minutes at a temperature of 25-30 °C. After this, fermentation is carried out in an anaerobic fermentation chamber in an atmosphere of carbon dioxide at a temperature of 30-35 °C at a temperature of 30-35 °C and a relative humidity of 60-70% for 8-12 hours. Then the raw material is sent to a low-temperature drying chamber with forced ventilation for drying at a temperature of no more than 45 °C to a residual moisture content of no more than 6%. From the drying chamber, the tea stalks are fed into an air separator to remove dust and unwanted particles, after which the finished product is sent to a storage silo for storage in a ventilated area until it reaches a temperature of 18-23°C.

[0016] The withering process reduces the moisture content of tea stems to 60-65%. This increases the tissue's sensitivity to further processing. Withering also stimulates oxidative stress and triggers the biosynthesis of antioxidants (catechins, flavonoids).

[0017] High Hydrostatic Pressure (HHP) is an advanced non-thermal technology for processing food raw materials, including plant-based ones. When applied to tea stems, pressure affects the internal cellular structure, causing mechanical and biochemical changes, including partial destruction of cell walls, the initiation of stress responses (including the formation of GABA), and an increase in the yield of soluble substances during subsequent extraction or fermentation. Antioxidants such as catechins, polyphenols, rutin, and flavonoids are not destroyed by heating.

[0018] The combined treatment with succinic acid salt (succinate) and monosodium glutamate enhances the accumulation of GABA and improves the antioxidant and sensory properties of tea through a comprehensive effect on metabolism and fermentation.

[0019] Treatment with succinic acid solution creates metabolic conditions conducive to GABA synthesis. GABA is metabolized to succinate, which can then enter the Krebs cycle. This interaction is particularly important, as it has a multi-level effect on the body, particularly on the nervous system, energy metabolism, and stress-relieving and adaptive mechanisms.

[0020] Treating tea stalks with a solution of succinic acid salt (succinate) stabilizes the pH. At pH 5.0-6.5, succinate acts as a mild buffer. Lowering the pH can inhibit fermentation by reducing the oxidation of catechins, thereby masking the flavor and revealing a less bitter and astringent aroma. Furthermore, succinate is a cofactor in the regulation of energy metabolism. The use of succinates in tea processing offers the potential to enhance antioxidant and stimulating effects, both through the metabolic action of the succinates themselves and through synergy with natural tea components (caffeine and theanine).

[0021] Monosodium glutamate provides the direct substrate—the precursor for GABA formation. Together with succinate, they increase the overall GABA level in tea stems after fermentation, improving the functional properties of the beverage.

[0022] Fermentation under anaerobic conditions in a carbon dioxide atmosphere is necessary to activate the enzyme glutamate decarboxylase, which converts glutamic acid salts into γ-aminobutyric acid, promotes the accumulation of GABA and reduces the oxidative breakdown of polyphenols, increasing the antioxidant activity of tea.

[0023] In a carbon dioxide atmosphere, the activity of oxidative enzymes is suppressed, preserving antioxidants and amino acids. Fermentation activates the flavonoid complex (especially thearubigins and theaflavins).

[0024] A temperature of 30-35°C, a relative humidity of 60-70%, and a process time of 8-12 hours also provide optimal conditions for glutamic acid decarboxylase activity. At temperatures above 37°C, enzyme activity decreases.

[0025] Anaerobic conditions and slow fermentation (8-12 hours) prevent the breakdown of aromatic substances, especially theanine, linalool, geraniol and other volatile components.

[0026] Gentle drying at a temperature not exceeding 45°C allows preserving heat-labile antioxidants.

[0027] As a result, the drink acquires a soft, rich taste with fruity and spicy notes.

[0028] The claimed method for producing tea from tea stems yields tea with a high content of γ-aminobutyric acid and antioxidants. Furthermore, the claimed integrated technology of treating tea stems with high hydrostatic pressure, a solution of succinic acid and monosodium glutamate, fermentation under anaerobic conditions, and drying allows for the release of extractive substances, which also enhances the unique woody flavor and removes the specific aroma of tea stems, thereby improving the sensory and physicochemical properties of tea. Thus, the combination of the claimed features of the invention enables the achievement of a technical result.

[0029] The author of the declared technical solution has produced experimental samples of tea from tea stalks of the "Colchis" variety, the production method of which is explained with examples of specific implementation.

[0030] Examples of specific implementation.

[0031] Example 1. Pre-screened tea stalks in the amount of 1000 g are withered on trays at a temperature of at least 26°C for 10 hours. Afterwards, the raw materials are exposed to high hydrostatic pressure, for which they are hermetically packed in durable polyamide / polyethylene bags resistant to high pressures, from which air is pumped out (vacuum), hermetically sealed. The bags are loaded into a Laboratory HHP 6L hydrostatic chamber filled with water, which is sealed. After this, the pump supplies water into a closed system to a pressure of 200 MPa and maintains it for 15 minutes at a liquid temperature of 35°C. Then the chamber is vented, the bags with tea stalks are removed. Then the raw materials are uniformly sprayed once with an aqueous solution containing 0.2 wt. % succinic acid salt (sodium succinate) and 0.1 wt. % of monosodium glutamic acid salt, in the amount of 400 ml per 1 kg of petioles with 60 min aging at a temperature of 25°C.Following this, fermentation takes place in an anaerobic fermentation chamber in a carbon dioxide atmosphere at a temperature of 30°C and a relative humidity of 70% for 10 hours. The raw material is then transferred to a drying chamber for drying at a temperature no higher than 45°C to a residual moisture content of no more than 6%. From the drying chamber, the tea stalks are fed into an air separator to remove dust and unwanted particles, after which the finished product is placed in a storage silo for maturation in a ventilated area until it reaches a temperature of 21°C.

[0032] The physicochemical and sensory properties of the obtained product are given in the table.

[0033] Example 2. Pre-screened tea stalks in the amount of 1000 g are withered on trays at a temperature of at least 26°C for 10 hours. Afterwards, the raw materials are exposed to high hydrostatic pressure, for which they are hermetically packed in durable polyamide / polyethylene bags resistant to high pressures, from which air is pumped out (vacuum), hermetically sealed. The bags are loaded into a Laboratory HHP 6L hydrostatic chamber filled with water, which is sealed. After this, the pump supplies water into a closed system to a pressure of 300 MPa and maintains it for 5 minutes at a liquid temperature of 25°C. Then the chamber is vented, the bags with tea stalks are removed. Then the raw materials are uniformly sprayed once with an aqueous solution containing 0.2 wt. % succinic acid salt (sodium succinate) and 0.1 wt. % monosodium glutamic acid salt, in the amount of 300 ml per 1 kg of petioles with 30 min aging at 27°C.Following this, fermentation takes place in an anaerobic fermentation chamber in a carbon dioxide atmosphere at a temperature of 35°C and a relative humidity of 60% for 12 hours. The raw material is then transferred to a drying chamber for drying at a temperature no higher than 45°C to a residual moisture content of no more than 6%. From the drying chamber, the tea stalks are fed to an air separator to remove dust and unwanted particles, after which the finished product is placed in a storage silo for maturation in a ventilated area until it reaches a temperature of 18°C.

[0034] The physicochemical and sensory indicators of the target product are shown in the table.

[0035] Example 3. Pre-screened tea stalks in the amount of 1000 g are withered on trays at a temperature of at least 26°C for 10 hours. Afterwards, the raw materials are exposed to high hydrostatic pressure, for which they are hermetically packed in durable polyamide / polyethylene bags resistant to high pressures, from which air is pumped out (vacuum), hermetically sealed. The bags are loaded into a Laboratory HHP 6L hydrostatic chamber filled with water, which is sealed. After this, the pump supplies water into a closed system to a pressure of 100 MPa and maintains it for 10 minutes at a liquid temperature of 20°C. Then the chamber is vented, the bags with tea stalks are removed. Then the raw materials are uniformly sprayed once with an aqueous solution containing 0.2 wt. % succinic acid salt (sodium succinate) and 0.1 wt. % monosodium glutamic acid salt, in the amount of 500 ml per 1 kg of petioles with 45 minutes of holding at 30°C.Following this, fermentation takes place in an anaerobic fermentation chamber in a carbon dioxide atmosphere at a temperature of 32°C and a relative humidity of 75% for 8 hours. The raw material is then transferred to a drying chamber for drying at a temperature no higher than 45°C to a residual moisture content of no more than 6%. From the drying chamber, the tea stalks are fed to an air separator to remove dust and unwanted particles, after which the finished product is placed in a storage silo for maturation in a ventilated area until it reaches a temperature of 23°C.

[0036] The physicochemical and sensory indicators of the target product are shown in the table.

[0037]

[0038] Industrial applicability.

[0039] The claimed technical solution is implemented using commercially available devices and materials and can be implemented at any tea processing facility. The use of tea stalks, a secondary raw material and waste product from tea harvesting and processing, allows for the production of new tea products with a high content of gamma-aminobutyric acid and antioxidant activity.

[0040] SOURCES OF INFORMATION.

[0041] 1. CN Patent No. 103005020, for the invention “Red tea with a high content of gamma-aminobutyric acid (GABA) for maintaining health” (published on 03.04.2013).

[0042] 2. Patent WO 2006021317 A1 for the invention “Method for preparing tea” (published 02.03.2006).

Claims

A method for producing tea, including withering of raw materials, fermentation and drying, characterized in that tea stalks are used as raw materials, and after withering, the tea stalks, pre-packed in flexible sealed containers, are exposed to high hydrostatic pressure in the range of 100-300 MPa for 5-15 minutes at a liquid phase temperature of 20-35 ° C, then the stalks are removed from the containers and treated with an aqueous solution containing 0.2 wt.% succinic acid salt and 0.1 wt.% monosodium glutamate, in a volume of 300-500 ml per 1 kg of raw materials with uniform distribution of the solution over the surface of the stalks and holding for 30-60 minutes at a temperature of 25-30 ° C, after which fermentation is carried out in an atmosphere of carbon dioxide at a temperature of 30-35 ° C and a humidity of 60-70% for 8-12 hours, and drying is carried out at a temperature of up to 45°C until the residual moisture content is no more than 6%, followed by separation and aging.

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