Method for improving quality of flower and fruit aroma black tea in plant factory

Abstract

The invention relates to the field of tea tree cultivation, and discloses a method for improving the quality of flower and fruit aroma black tea in a plant factory, which comprises the following steps: (1) selecting Jinguanyin tea seedlings planted in the plant factory for 4 years as test materials, after field planting, combining 400-499nm blue light (22-25%), 600-699nm red light (50-51%) and 700-788nm red light (24-28%) in the whole tea tree cultivation period, the light intensity is 200-400 [mu] mol / m < 2 >. S, and the photoperiod is 12-14 h / d; (2) 3 days before harvesting, based on a cultivation period spectrum, increasing 320-399 nm ultraviolet UVA (3-7%) for combined use, the light intensity being 150-400 [mu] mol / m < 2 >. S, the light period being 10-14 h / d, the planting environment day and night temperature being 26-28 / 18-20 DEG C, and the humidity being 60-70%; and (3) performing subsequent conventional black tea making process on the harvested fresh tea leaves to obtain the flower and fruit flavor black tea, wherein the standard of the picked tea leaves is one bud and two leaves and one bud and one leaf. Through the light regulation and control technology, the obtained black tea is rich in flower and fruit fragrance and mellow and sweet in tea taste, meanwhile, the bitter taste of the black tea is reduced, and therefore the quality of the black tea is improved.

Description

Technical Field

[0001] The invention relates to the field of tea tree cultivation, in particular to a method for improving the quality of floral and fruity black tea produced in a plant factory. Background Art

[0002] Black tea is one of the most popular teas in the world. According to statistics, black tea consumption accounts for more than 60% of the world's tea. Although black tea consumption in my country accounts for only about 17% of the total, second only to green tea, in recent years, black tea has set off a wave of enthusiasm in China, gradually gaining favor among the middle-aged and elderly groups and young consumer groups, and its market share continues to increase. Among them, floral and fruity black tea is one of the most launched black tea categories.

[0003] Existing flower-fruit black tea is mainly obtained by interplanting black tea trees with some fragrant flowers and fruit trees, scenting black tea with fragrant flowers and fruits, absorbing the fragrance of flowers and fruits, or obtaining fragrance by using some industrial additives. Although these methods can improve the fragrance of black tea to a certain extent, they will make black tea lose its original flavor, and the coordination between aroma and taste is poor, thus limiting the wide application of flower-fruit black tea. At present, the flower-fruit black tea on the market has a heavy bitter taste, the tea leaves are not fresh enough, and the mellow and sweet flavor is insufficient.

[0004] With the development of plant factories, it provides unlimited possibilities for indoor cultivation of various crops. Plant factories are general artificial light sources that replace sunlight to meet the energy required for plant growth, and at the same time provide the temperature, humidity, water, fertilizer, air and other elements required for plant growth. Light is one of the most critical factors for plant growth in plant factories. At present, some studies have reported the effect of artificial light sources on the quality regulation of black tea. In the published document "Investigation of the Effect of Withering with Different Light Quality on the Quality of Black Tea", Hu Xin et al. showed that the content of water extract and caffeine decreased significantly after blue light withering treatment, but the appearance, soup color, aroma and leaf bottom evaluation scored the highest. In the published document "The Effect of Different Light Quality on the Volatile Components of Summer and Autumn Black Tea Withering Leaves", Li Yuchuan et al. showed that different light qualities had a significant effect on the volatile components of summer and autumn black tea withering leaves, and yellow light withering treatment could improve the aroma quality of summer and autumn black tea. In the paper "The Effect of Light Withering on the Quality of Black Tea from Different Tea Varieties" published by Luo Hongyu et al., the study showed that yellow light is beneficial to increasing the content of soluble sugar and free amino acids in Fuding Da Baicha black tea and Sichuan small and medium-leaf black tea.

[0005] The prior art shows that when using LED light sources to control the quality of black tea, yellow light and blue light should be used as much as possible to promote the improvement of tea aroma and quality. Based on the above background, the present invention proposes a light control technology for the quality of black tea plant factories. Summary of the invention

[0006] To this end, the present invention provides a light regulation technology to obtain black tea with rich floral and fruity aroma, mellow and sweet tea taste, while reducing the bitterness of the black tea, thereby improving the quality of the black tea.

[0007] To achieve the above object, the present invention provides a method for improving the quality of floral and fruity black tea produced in a plant factory, comprising the following steps:

[0008] (1) Golden Guanyin tea seedlings planted in a plant factory for 4 years were selected as experimental materials. After planting, a combination of 400-499nm blue light (22-25%), 600-699nm red light (50-51%), and 700-788nm red light (24-28%) was used throughout the tea tree cultivation period, with a light intensity of 200-400μmol / ㎡·s and a photoperiod of 12-14h / d;

[0009] (2) 3 days before harvest, add 320-399nm UVA (3-7%) to the spectrum during the cultivation period, with a light intensity of 150-400μmol / ㎡·s, a photoperiod of 10-14h / d, a day and night temperature of 26-28 / 18-20℃, a humidity of 60-70%, and a day and night CO2 concentration of 1000 / 400ppm; by changing the formula, a proper stress effect is exerted on the young tea buds, promoting the accumulation of aroma and flavor substances contained therein;

[0010] (3) The standard for picking green tea leaves is 1 bud and 2 leaves or 1 bud and 1 leaf. After the green tea leaves are picked, they can be subjected to the conventional black tea production process to obtain floral and fruity black tea.

[0011] The above technical solution has the following beneficial effects:

[0012] The light regulation technology is used to obtain black tea with rich floral and fruity aroma and mellow and sweet tea taste, while reducing the bitterness of the black tea, thereby improving the quality of the black tea. DETAILED DESCRIPTION

[0013] In order to explain the technical content, structural features, achieved objectives and effects of the technical solution in detail, the following is a detailed description in conjunction with specific embodiments.

[0014] A method for improving the quality of floral and fruity black tea produced in a plant factory comprises the following steps:

[0015] (1) Selected adult tea seedlings of Golden Guanyin planted in a plant factory for 4 years as test materials, the ambient temperature was 28 / 20℃, the humidity was 65%, the CO2 concentration was 1000 / 400ppm, and the nutrient solution system was drip irrigation. Each plant was irrigated once every 1d, 300ml each time, the EC value of the nutrient solution was 1.5-2.0mS / cm, and the pH was 5.0-6.0. The light source system used LED lighting for supplementary lighting. The light source set different light environments in different embodiments according to the cultivation period and harvest period of the tea tree, and set a control group, as shown in Table 1 below.

[0016] Table 1. Cultivation environment of Examples 1-4 and Comparative Examples 1-8

[0017]

[0018] The light intensity of each treatment was set to 250 μmol / ㎡·s, and the photoperiod was 12h / d. The tea trees were cultivated using the above method, and green tea was harvested every 50-60 days. The green tea yield was counted, and the subsequent production process of black tea was followed by counting the withering time required for each treatment. The Golden Guanyin was made into finished black tea, and the black tea product was subjected to sensory evaluation according to national standards. Samples were sent for determination of caffeine and soluble sugar content. The test results are shown in Table 2:

[0019] Table 2. Green tea quality of Examples 1-4 and Comparative Examples 1-8

[0020]

[0021] The results show that the control example 7 is the LED light source solution currently used in indoor tea cultivation, and a unified light source solution is used throughout the tea cultivation cycle. The control examples 1-2 are full spectrum solutions in the range of 400-780nm commonly used in the cultivation light source market. While embodiments 1-4 adopt a two-stage light source solution, by setting a specific spectrum during the cultivation period, abandoning the commonly used yellow-green light part, and only retaining the blue light, red light and far-red light parts, it can accelerate the growth of Jinguanyin tea seedlings and increase the yield of green tea. At the same time, by adding a specific ultraviolet light UVA band 320-380nm and a specific dosage 3 days before harvesting, before the fresh green tea leaves are harvested, the tender leaf buds of the tea tree are properly stressed, causing red stress damage on the edges of the leaves to promote the production and transformation of volatile and non-volatile substances in the fresh leaves. After picking, the finished black tea is made using the traditional black tea process, and the withering market is also greatly shortened. At the same time, the caffeine content of the finished tea is significantly reduced and the soluble sugar content is increased. The finished tea has a strong fruity aroma and a mellow taste without bitterness. Through the above light regulation technology, unexpected technical effects have been achieved.

[0022] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or terminal device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "include..." or "comprise..." do not exclude the existence of other elements in the process, method, article or terminal device including the elements. In addition, in this article, "greater than", "less than", "exceed" and the like are understood to exclude the number itself; "above", "below", "within" and the like are understood to include the number itself.

[0023] Although the above embodiments have been described, once those skilled in the art know the basic creative concepts, they can make additional changes and modifications to these embodiments. Therefore, the above description is only an embodiment of the present invention and does not limit the patent protection scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for improving the quality of floral and fruity black tea produced in a plant factory, characterized in that: The steps include: (1) Select tea seedlings grown in a plant factory as experimental materials; (2) Cultivation period: Set the light environment: the proportion of 400-499nm blue light photons to the total photons is 22-25%, the proportion of 600-699nm red light photons to the total photons is 50-51%, the proportion of 700-788nm red light photons to the total photons is 24-28%, the light intensity is 200-400μmol / ㎡·s, and the photoperiod is 12-14h / d; (3) Harvesting period: 3 days before harvesting, set the light environment: the proportion of 320-399nm ultraviolet light UVA photons to the total photons is 3-7%, the proportion of 400-499nm blue light photons to the total photons is 20.9-23.75%, the proportion of 600-699nm red light photons to the total photons is 47.43-48.5%, the proportion of 700-788nm red light photons to the total photons is 22.32-27.16%, the light intensity is 150-400μmol / ㎡·s, the photoperiod is 10-14h / d, and then harvest. After harvesting, adjust the light environment to the cultivation period, and then wait until the buds sprout again, and then adjust the light environment to the harvest period. The green tea can be harvested every 50-60 days.

2. A method for improving the quality of floral and fruity black tea in a plant factory as claimed in claim 1, characterized in that: During the entire planting period, the ambient temperature is 26-28 / 18-20℃ day and night, the humidity is 60-70%, and the CO2 concentration is controlled at 1000 / 400ppm day and night.

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