Method for preparing tea products using tea stems

Abstract

The invention discloses a method for preparing tea products by using tea stems, which uses discarded branches pruned from a tea garden as raw materials, including the steps of selecting and removing leaves, grinding, spraying enzyme liquid at high pressure, microwave sterilization, rapid cooling and separation, cutting and drying, and finally preparing the desired tea products. The invention is the first to prepare tea products by processing tea stems, which fills the gap in the field of tea stem processing, enables the discarded branches pruned from tea gardens to be utilized, and improves the economic value. The invention is subjected to processes such as grinding, spraying enzyme liquid at high pressure, microwave sterilization, rapid cooling and separation, and the like, and under the action of enzymes and heat, the contents of the cortex of the tender stems, such as proteins, polysaccharides, polyphenols and other macromolecular substances, are degraded to form amino acids, soluble sugars, catechins and the like, and finally prepare tea stem products with low caffeine content and suitable for drinking by teenagers, which are also a condiment for cooking, boiling eggs, hot pot, etc., and have high economic and nutritional value.

Description

Technical Field

[0001] The invention belongs to a method for preparing tea products by using tea stems, and in particular relates to a method for preparing a novel tea product by using discarded branches pruned from a tea garden. Background Art

[0002] Tea trees belong to the genus Camellia of the Theaceae family, the subfamily Camellia, and are perennial evergreen woody plants. Their leaves can be used to make tea, their seeds can be used to extract oil, and their wood can be used for carving. According to the classification method of the Chinese Tea Classic edited by Chen Zongmao, tea varieties can be divided into: green tea, black tea, yellow tea, white tea, yellow tea, dark tea, and processed tea. However, traditional tea science usually involves a series of processing of tea buds and leaves to form various tea products, but there are few reports on methods of preparing tea products using tea stems.

[0003] Tea stems are organs that connect the roots of tea trees with leaves, flowers, and fruits. They mainly transport water, inorganic salts, and organic nutrients. Tea stems are also commonly called tea stalks and tea branches. Compared with buds and tender leaves, tea stems are relatively thick and old. In the process of production and management of tea gardens, tea trees need to be pruned. Pruning usually includes: shaping pruning, light pruning, heavy pruning, and table pruning. Light pruning is performed once a year, and heavy pruning is generally performed every 3 to 5 years. The pruned branches are often discarded by tea farmers in the tea garden and cannot be used.

[0004] The polysaccharides, amino acids and aroma substances in tea stems are higher than those in buds and leaves. For example, the amino acid content in tea stems is 5.73%, higher than the 1.83% in buds and leaves; the crude fiber content in tea stems is 17.08%, higher than the 10.87% in buds and leaves.

[0005] Among them, polysaccharides can increase the sweetness and thick taste of tea soup, and tea polysaccharides are a type of polysaccharide complex with multiple biological activities present in tea leaves. It has multiple functions such as lowering blood sugar, anti-oxidation, lowering blood lipids, and anti-fatigue.

[0006] Theanine is a free amino acid unique to tea trees. Its content in young stems is 1-3 times higher than that in buds and leaves. Free amino acids are the main component that makes tea soup taste fresh and refreshing.

[0007] Tea stems contain a considerable amount of aroma substances. The aroma of tea leaves gradually decreases from the first leaf to the third leaf, and the aroma of tea stems is the highest. Aroma is an important factor affecting the quality of tea products. It mainly comes from the free aroma components and bonded aroma components in the tea stems, as well as the aroma components converted by enzymatic and thermal reactions during the processing. Therefore, tea products processed from tea stems not only have a sweet and refreshing taste, but also have a unique aroma.

[0008] In addition, studies have shown that the caffeine content in tea stems (1.63%) is much lower than the caffeine content in buds and leaves (3.78%). Therefore, tea products prepared from tea stems are more suitable for teenagers than traditional tea beverages. It is also a condiment for cooking, boiling eggs, hot pot, etc., and has broad market prospects. Summary of the invention

[0009] In view of this, the present invention provides a method for preparing tea products using tea stems. Aiming at the current situation that the discarded branches pruned from existing tea gardens are discarded by tea farmers, resulting in a waste of resources, and the problem that existing tea products are not suitable for young people to drink due to their high caffeine content, a method for preparing a new type of tea product with sweet, mellow and refreshing tea soup, rich aroma and more suitable for young people to drink is proposed.

[0010] The technical solution of the present invention is: a method for preparing tea products using tea stems, using discarded branches pruned from a tea garden as raw materials, comprising the following steps:

[0011] 1) Picking and removing leaves: Pick green and yellow non-lignified tender stems and red semi-lignified tea stems from the discarded branches pruned in the tea garden, remove the leaves and lignified branches, and then wash the selected tea stems 2-3 times.

[0012] 2) Grinding and high-pressure spraying of enzyme solution: The cleaned branches are evenly placed in a shaking device to damage their cortex. The aforementioned shaking device is a customized device, which is characterized in that the device has a shaking bed for accommodating branches, and the inner wall of the shaking bed that can contact the branches is provided with an uneven concave-convex structure or a specific structure that can rub and collide with the branches. When the shaking device is working, the cortex is worn out by the collision and friction between the inner wall of the shaking bed and the branches. When the branch breakage rate reaches more than 60%, the shaking device is turned off. Then, the enzyme solution is sprayed on the surface of the branch with a high-pressure spray gun so that the enzyme solution fully penetrates into the above-mentioned damaged position. Before spraying the enzyme solution, the cortex of the tea stem is first worn out by the shaking device, which is conducive to the adsorption of the enzyme solution, and then the composite enzyme is used to directly act on the cell wall to destroy the cell wall. Under the enzymatic action, it is more beneficial to degrade and fully release the contents of the surface layer of the tender stem.

[0013] 3) Microwave sterilization: The tender stems are placed in a microwave at 150-180°C for sterilization for 6-8 minutes. Microwave sterilization can destroy the activity of enzymes at high temperature and inhibit further degradation.

[0014] 4) Cooling and separation: Place the microwave-killed branches quickly in cold water, and use the principle of thermal expansion and contraction to initially separate the phloem from the middle xylem. Then take out the branches, cut the phloem with a knife, and completely separate the phloem from the xylem. Take the phloem of the tea stems for later use.

[0015] 5) Cutting and drying: The separated phloem is cut into small segments of about 2-3 cm, and then dried in a hot air environment of 80-100°C to obtain the desired tea products.

[0016] Furthermore, in step 2), the enzyme solution is a mixture of cellulase and pectinase, and the mass ratio of the two is 1-1.5:1. In the high-pressure spraying of the enzyme solution, the ratio of the mass of the enzyme solution sprayed to the mass of the branches to be treated is 5‰-6‰. Cellulase can act on cellulose in the cell wall to increase the permeability of the cell wall, which is conducive to the release of substances contained in the tea stem; pectinase mainly acts on pectin in the cell wall, and by destroying the amorphous structure composed of hemicellulose and pectin, it is conducive to the exudation and diffusion of effective ingredients in the tea stem.

[0017] The present invention utilizes the characteristics of "polysaccharide substances, amino acids and aroma substances in tea stems are higher than those in buds and leaves, and caffeine content is lower than that in buds and leaves", selects specific tea stems from the discarded branches pruned in the tea garden, and finally obtains the required tea products through the steps of selecting and removing leaves, grinding skin, high-pressure spraying of enzyme solution, microwave sterilization, rapid cooling and separation, cutting and drying. Before applying the composite enzyme, the surface cell structure of the tea stem is first destroyed by a vibration bed, which is conducive to the subsequent adsorption of the enzyme solution. By spraying the composite enzyme at high pressure, the effective components in the cortical cells are fully analyzed by enzymatic reaction, so that the macromolecular substances such as proteins, polysaccharides, polyphenols and the like in the cortex are degraded to form amino acids, soluble sugars, catechins and the like. Microwave sterilization is adopted to rapidly destroy the activity of the composite enzyme by high temperature, fix the quality of the tea stem, and do not change the nutritional components of the included substances. During the sterilization process, the amino acid content increases, and the content of tea polyphenols, caffeine and the like decreases, further improving the flavor of the tea products. After the tea leaves are withered, the tea stems are quickly placed in cold water, and the principle of "thermal expansion and contraction" is used to initially separate the wood and phloem in the middle. The cortex is then cut with a knife to completely separate the phloem and wood, resulting in a stem cortex that is easier to extract nutrients when brewing. Finally, the cortex is cut into 2-3 cm small sections and dried to obtain a new type of tea product suitable for young people.

[0018] Beneficial effects:

[0019] The invention is the first to prepare tea products by processing tea stems, filling the blank in the field of tea stem processing, making use of discarded branches pruned from tea gardens, and "turning waste into treasure". Through processes such as skin grinding, high-pressure spraying of enzyme solution, microwave sterilization, rapid cooling and separation, the tender stems are degraded under the action of enzymes and heat, such as macromolecular substances such as protein, polysaccharides, polyphenols, etc. in the cortex to form amino acids, soluble sugars, catechins, etc., and finally the tea stem products with low caffeine content suitable for drinking by teenagers are made. At the same time, the tea stem products are also a condiment for cooking, boiling eggs, hot pot, etc., and have high economic and nutritional value.

[0020] The present invention will be described in more detail below with reference to the embodiments. DETAILED DESCRIPTION

[0021] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0022] Embodiment 1,

[0023] This embodiment provides a method for preparing tea products using tea stems, comprising the following steps:

[0024] (1) Selection step: Select the desired green and yellow tender stems from the discarded stems and leaves after pruning in the tea garden as raw materials. The object in this embodiment is Huangshan large-leaf tea trees. Unqualified tender stems are visually excluded, and the leaves and lignified branches of the tender stems that meet the requirements are removed and then washed 2-3 times to ensure the quality of the raw materials.

[0025] (2) Skin grinding steps: The cleaned tender stems are naturally dried in the sun for 1 day, during which they are turned over several times to dry the surface of the tender stems. They are then evenly placed on the shaking bed of a shaking machine to break the skin and keep them ready for use.

[0026] (3) High-pressure enzyme liquid spraying step: Take cellulase (2000 U / g) produced by Beijing Shengshi Jiaming Technology Development Co., Ltd. and pectinase (3000 U / g) produced by Ningxia Heshibi Biotechnology Co., Ltd., and mix them in a ratio of 1:1 to prepare a composite enzyme; the ratio of the mass of the composite enzyme to the mass of the branches on the vibration bed is 6‰, and then use a high-pressure spray gun to spray the enzyme liquid on the surface of the tea stem, so that the enzyme liquid can fully penetrate into the damaged part of the cortex of the tea stem and directly act on the cell wall to release the substances contained therein.

[0027] (4) Microwave sterilization step: The tea stems were removed from the shaking bed and sterilized in a microwave at 150°C for 8 minutes.

[0028] (5) Cooling and separation step: The tender stems after microwave sterilization are quickly placed in cold water at 5-10°C to initially separate the cortex of the tender stems from the wood in the middle, and then the cortex is cut with a knife to completely separate the cortex from the wood in the middle for later use.

[0029] (6) Cutting and drying step: The separated cortex is cut into small segments of about 2-3 cm, and then dried with hot air to obtain the desired tea product.

[0030] Embodiment 2,

[0031] The difference from Example 1 is that in the picking step, the required red semi-lignified branches are picked from the discarded stems and leaves after pruning in the tea garden as raw materials; in the high-pressure spraying enzyme solution step, the ratio of cellulase to pectinase is 1.5:1, and the composite enzyme is prepared, and the mass ratio of the composite enzyme to the mass of the branches on the vibration bed is 5‰; in the microwave killing step, the killing treatment is carried out under microwaves at 180°C for 6 minutes. The rest is the same as Example 1.

[0032] Embodiment 3,

[0033] The difference from Example 1 is that in the picking step, in addition to picking green and yellow tender stems as raw materials from the discarded stems and leaves after pruning in the tea garden, red semi-lignified branches are also selected as raw materials; in the high-pressure spraying enzyme solution step, the ratio of cellulase to pectinase is 1.3:1 to prepare a composite enzyme; the mass ratio of the composite enzyme to the mass of the branches on the vibration bed is 5.5‰, and in the microwave killing step, the killing treatment is carried out under a microwave at 180°C for 8 minutes. The rest is the same as Example 1.

[0034] Table 1 shows the test results of the nutritional components of tea products prepared using tea stems in Examples 1 to 3, and the test results are provided by the Tea Quality Supervision, Inspection and Testing Center of the Ministry of Agriculture and Rural Affairs. It can be seen from the data in the table that the tea products prepared by the present invention are rich in polysaccharides (such as crude fiber, starch, pectin, etc.), amino acids (such as theanine), and polyphenols, and the caffeine content is lower than that of Huangshan Maofeng tea and Chaoqing tea shown in Comparative Examples 1 and 2.

[0035] Table 1 Comparison of nutritional component test results of Examples 1 to 3 and Comparative Examples

[0036]

[0037] The present invention is described above by way of example. For example, the preparation method described in the present invention can be used to prepare tea products and can also be applied to cooking, boiling eggs, hot pot and other condiment processing fields. Obviously, the specific implementation of the present invention is not limited by the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention; or the above concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A method for preparing tea products using tea stems, using discarded branches pruned from tea gardens as raw materials, characterized in that: It includes the steps of leaf picking and defoliation, skin grinding, high-pressure enzyme spraying, microwave sterilization, cooling and separation, and cutting and drying. The picking and leaf removal process is to pick green and yellow non-lignified tender stems and red semi-lignified tea stems from the discarded branches pruned in the tea garden, then remove the leaves and lignified branches, and then wash the picked branches 2-3 times; The grinding process is to place the cleaned branches in a shaking machine to damage the surface of the branches. The shaking machine has a shaking bed for accommodating the branches. The inner wall of the shaking bed that can contact the branches is provided with an uneven concave-convex structure or a structure that can rub and collide with the branches. When working, the uneven inner wall of the shaking machine rubs against the branches to grind the surface of the branches. When the damage rate of the branches reaches more than 60%, the machine stops working. The high-pressure enzyme liquid spraying process is to use a high-pressure spray gun to evenly apply the enzyme liquid on the surface of the branches treated by the shaking machine, so that the enzyme liquid fully penetrates into the damaged parts of the surface of the branches; the enzyme liquid is a mixture of cellulase and pectinase, and the mass ratio of the two is cellulase: pectinase = 1-1.5:1; the ratio of the mass of the enzyme liquid spraying to the mass of the branches to be treated is 5‰ ~ 6‰; The microwave sterilization process is to place the branches treated with the enzyme solution under a microwave at 150-180° C. for sterilization for 6-8 minutes; The cooling and separation process comprises: placing the microwave-killed branches quickly in cold water to initially separate the phloem from the wood in the middle, then taking out the branches, cutting the phloem with a knife, separating the phloem from the wood in the middle, and obtaining the tea stem phloem; The cutting and drying process is to first cut the separated tea stem phloem into small segments of 2-3 cm, and then dry them at 80-100° C., so as to obtain the desired tea product.

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