A light control method for indoor withering of white tea

Abstract

The invention discloses a light regulation method for indoor withering of white tea, the light regulation method comprises withering the white tea with an artificial light source, wherein in the artificial light source, the proportion of the number of photons of 400-499nm to the total photons is 9.21-14.89%, the proportion of the number of photons of 500-599nm to the total photons is 12.89-18%, the proportion of the number of photons of 600-699nm to the total photons is 39.79-45.02%, and the proportion of the number of photons of 700-780nm to the total photons is 26.98-33%. The light regulation method of the invention can effectively reduce the content of bitter substances such as tea polyphenols and caffeine in the finished white tea, and the prepared white tea soup is apricot yellow and bright, fresh and smooth, with a pure aroma and a fresh fragrance, and the leaf bottom is uniform.

Description

Technical Field

[0001] The invention relates to a light regulation method for indoor withering of white tea. Background Art

[0002] White tea processing consists of two steps: withering and drying. The main withering methods include sunlight withering, compound withering and heated withering. Withering is a key process in the formation of white tea quality. The quality of white tea withered at different process levels varies greatly. Traditional white tea processing includes sunlight withering. Light provides the necessary environmental conditions and energy requirements for the physical reaction, biological metabolism and chemical changes of fresh leaves. It plays a positive role in the withering stage of white tea and can promote the transformation of the internal substances in the tea leaves and the accumulation of aroma precursor substances.

[0003] The wavelength and intensity of sunlight vary with different weather conditions, and it often rains during the tea season, so it is impossible to carry out sunlight withering, and the withering effect of fresh leaves cannot be guaranteed, which affects the controllability of withering and leads to unstable tea quality. Artificial light sources are used to improve the original natural withering conditions. Through light regulation, the formation of aroma precursors and the transformation of flavor quality components are promoted, ensuring the stability of tea quality and improving the flavor quality of tea.

[0004] Different light quality, light intensity, and illumination time have different effects on the formation of white tea flavor quality. Huang Fan believes that red light withering is beneficial to the improvement of the taste of white peony tea, while yellow light withering is beneficial to the formation of its aroma quality. Luo Lingna's research found that blue light can increase the content of tea polyphenols in white tea, and yellow light can increase the content of volatile substances such as (E)-2-hexenal, nerol and phenylethanol, promoting the formation of tea fragrance and floral fragrance. Sai Weiming and others believe that far-infrared light sources can increase the permeability and enzyme activity of the cell membrane inside the tea, promote the oxidation of polyphenols and the formation of aroma substances. Chen Jian and others used far-infrared withering technology in black tea processing and found that the astringency of the tea soup was reduced. Summary of the invention

[0005] Based on the above background, the purpose of the present invention is to provide a light control method for indoor withering of white tea. The present invention uses an artificial LED light source to wither white tea indoors. After a large number of experiments, the artificial light source of the present invention is screened out. The light control method of the present invention can ensure the stability of tea products and improve the flavor quality of tea.

[0006] The specific technical solution adopted by the present invention is:

[0007] A light regulation method for indoor withering of white tea comprises withering the white tea by using an artificial light source, wherein in the artificial light source, based on the percentage of light quality spectrum integration, the proportion of photons of 400-499nm to the total photons is 9.21-14.89%, the proportion of photons of 500-599nm to the total photons is 12.89-18%, the proportion of photons of 600-699nm to the total photons is 39.79-45.02%, and the proportion of photons of 700-780nm to the total photons is 26.98-33%.

[0008] Preferably, under artificial light, the tea leaves are evenly spread on a withering trough with a stacking thickness of 10-15 cm, and the tea leaves are withered using a withering trough device.

[0009] Preferably, the light intensity of the artificial light source is 70-80 μmol / ㎡·s.

[0010] Preferably, the artificial light source is an LED light source; during withering, continuous illumination is performed for 8-16 hours, and then withering is continued in darkness.

[0011] Further preferably, during withering, continuous illumination is performed for 8 hours.

[0012] Preferably, when the weight loss rate of the tea leaves reaches 70-75%, withering is completed.

[0013] Preferably, in the artificial light source, based on the percentage of light quality spectrum integration, the proportion of photons in the range of 400-499nm to the total photons is 9.21%, the proportion of photons in the range of 500-599nm to the total photons is 18%, the proportion of photons in the range of 600-699nm to the total photons is 39.79%, and the proportion of photons in the range of 700-780nm to the total photons is 33%.

[0014] Preferably, in the artificial light source, measured by the percentage of light quality spectrum integration, the proportion of photons in the range of 400-499nm to the total photons is 11.2%, the proportion of photons in the range of 500-599nm to the total photons is 13.68%, the proportion of photons in the range of 600-699nm to the total photons is 43.34%, and the proportion of photons in the range of 700-780nm to the total photons is 31.78%.

[0015] The beneficial effect of the present invention is that the light regulation method of the present invention can effectively reduce the content of tea polyphenols, caffeine and other bitter substances in the finished white tea, and the prepared white tea soup is bright apricot yellow, fresh and smooth in taste, pure and fragrant in aroma, and the leaf bottom is uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1Shown is the withering of white tea under different light environment conditions;

[0017] Figure 2 Shown are different light exposure times during the withering process of white tea. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below in conjunction with embodiments, but the embodiments of the present invention are not limited thereto. Without departing from the above-mentioned technical concept of the present invention, various substitutions and changes are made according to common technical knowledge and customary means in the field, which should all be included in the scope of the present invention.

[0019] Implementation Case 1

[0020] 1. Effects of different withering light environments on the quality of white tea

[0021] (1) Picking: Pick one bud and two or three leaves of Jiulong Da Baicha in autumn and set aside.

[0022] (2) Withering: Divide the picked fresh tea leaves into 14 even portions, spread them on the withering trough with a stacking thickness of 10-15 cm, and use the withering trough device to wither the tea leaves. The indoor withering environment temperature is 27-35°C and the humidity is 45-55%. Set up LED light sources with different light formulas above the withering trough, 1m 2 3-4 LED lamps were used, with the light source being 70-90 cm away from the surface of the fresh tea leaves, the withering light intensity being 70-80 μmol / ㎡·s, and the irradiation time being the same. Three groups of control examples and six groups of exemplary embodiments were set up respectively. The tea leaves were not turned over during the period. The withering was terminated when the fresh leaves withered to a weight loss rate of 70-75%, and the leaves were immediately dried and sampled.

[0023] (3) Quality testing: Samples treated with different light environments were dried and ground, and the flavor components such as free amino acids, caffeine, tea polyphenols, and soluble sugar in tea were determined according to national standards. The test results are shown in Table 1:

[0024] Table 1. Effects of different withering light environments on the quality components of white tea

[0025]

[0026]

[0027] (4) Sensory evaluation: Based on the national standard tea sensory evaluation method, a quality evaluation team composed of 5 professionals scored the white tea samples treated with different light environments. The evaluation results are shown in Table 2:

[0028] Table 2. Effects of different withering light environments on the sensory quality of white tea

[0029]

[0030] The evaluation factor scoring coefficients are appearance 25%, soup color 10%, aroma 25%, taste 30%, and leaf bottom 10%.

[0031] The results show that the sensory quality of tea leaves in combined light control examples 1-8 is not as good as dark withering or the difference between them and dark withering is not significant, and the withering effect is not good. The sensory quality of tea leaves in Examples 1-6 is higher than dark withering and other LED light source withering. The photothermal effect promotes the oxidation of polyphenols, reduces the content of tea polyphenols, reduces the bitterness of tea leaves, and is conducive to the formation of aroma substances; the caffeine content is significantly reduced, which is conducive to the reduction of the bitterness of the tea soup. Therefore, the overall taste of the tea soup is relatively fresh, refreshing and smooth.

[0032] Therefore, the best LED light source formula is: the proportion of 400-499nm photons to the total photons is 9.21-14.89%, the proportion of 500-599nm photons to the total photons is 12.89-18%, the proportion of 600-699nm photons to the total photons is 39.79-45.02%, and the proportion of 700-780nm photons to the total photons is 26.98-33%, which can effectively improve the freshness of white tea taste and improve the quality of white tea.

[0033] Implementation Case 2

[0034] Effects of different light durations on white tea quality during withering

[0035] (1) Picking: Pick one bud and two or three leaves of Jiulong Da Baicha in autumn and set aside.

[0036] (2) Withering: Divide the picked fresh tea leaves into 5 portions and spread them evenly on the withering trough with a stacking thickness of 10-15 cm. Use the withering trough device to wither the tea leaves. The indoor withering environment temperature is 27-35°C and the humidity is 45-55%. Set up an LED light source above the withering trough, 1m 2 Use 3-4 LED lamps, with the light source 70-90cm away from the surface of the fresh tea leaves, with a withering light intensity of 70-80μmol / ㎡·s. Turn on the LED light source when withering begins, and expose the leaves to light continuously for different lengths of time (8h, 16h, 24h, 32h). Use indoor withering (dark environment) during the same period as a control. The tea leaves are not turned over during this period. Withering is stopped when the weight loss rate of the fresh leaves reaches 70-75%, and the leaves are immediately dried and sampled.

[0037] (3) Quality testing: Samples with different light exposure times during the withering process were dried and ground, and the flavor components such as free amino acids, caffeine, tea polyphenols, and soluble sugars in tea were determined according to national standards. The test results are shown in Table 3:

[0038] (4) Sensory evaluation: Based on the national standard tea sensory evaluation method, a quality evaluation team composed of 5 professionals scored samples with different light exposure times during the withering process. The evaluation results are shown in Table 3:

[0039] Table 3. Effects of different light durations on white tea quality during withering

[0040]

[0041] The results showed that under different light exposure time withering, the comprehensive sensory quality of tea treated with 8h of light exposure was the best. Compared with the control, the content of tea polyphenols decreased by 13%, the content of caffeine decreased by 20%, and the content of free amino acids, water extracts and soluble sugars also increased slightly. The changes in these contents helped to reduce the bitterness of tea soup, improve the freshness of tea, and improve the overall quality of tea. However, with the extension of light exposure time, the sensory quality of tea continued to decline, tea polyphenols and caffeine showed an upward trend, and amino acids, soluble sugars and water extracts showed a downward trend. The changes in these ingredients were not conducive to the improvement of tea quality, and the sensory quality also gradually declined. In summary, it is believed that the best LED light source exposure time during the withering process of white tea is 8h, and it should not exceed 16h.

[0042] 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 by using the contents of the specification and drawings of the present invention, 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 light regulation method for indoor withering of white tea, characterized in that: The light regulation method comprises withering white tea with an artificial light source, wherein, in terms of light quality spectrum integral percentage, the proportion of photons in the range of 400-499 nm to the total photons is 9.21-14.89%, the proportion of photons in the range of 500-599 nm to the total photons is 12.89-18%, the proportion of photons in the range of 600-699 nm to the total photons is 39.79-45.02%, and the proportion of photons in the range of 700-780 nm to the total photons is 26.98-33%.

2. The light regulation method for indoor withering of white tea according to claim 1, characterized in that: Under artificial light, the tea leaves are evenly spread on the withering trough with a stacking thickness of 10-15 cm, and the tea leaves are withered using a withering trough device.

3. The light regulation method for indoor withering of white tea according to claim 1, characterized in that: The light intensity of the artificial light source is 70-80 μmol / ㎡·s.

4. The light regulation method for indoor withering of white tea according to claim 1, characterized in that: The artificial light source is an LED light source; during withering, continuous illumination is performed for 8-16 hours, and then withering is continued in darkness.

5. The light regulation method for indoor withering of white tea according to claim 4, characterized in that: During withering, continuous light exposure is 8 hours.

6. The light regulation method for indoor withering of white tea according to claim 4, characterized in that: When the weight loss rate of tea leaves reaches 70-75%, withering is completed.

7. A light regulation method for indoor withering of white tea according to any one of claims 1 to 6, characterized in that: In the artificial light source, based on the percentage of light quality spectrum integration, the proportion of photons in the range of 400-499nm to the total photons is 9.21%, the proportion of photons in the range of 500-599nm to the total photons is 18%, the proportion of photons in the range of 600-699nm to the total photons is 39.79%, and the proportion of photons in the range of 700-780nm to the total photons is 33%.

8. A light regulation method for indoor withering of white tea according to any one of claims 1 to 6, characterized in that: In the artificial light source, based on the percentage of light quality spectrum integration, the proportion of photons in the range of 400-499nm to the total photons is 11.2%, the proportion of photons in the range of 500-599nm to the total photons is 13.68%, the proportion of photons in the range of 600-699nm to the total photons is 43.34%, and the proportion of photons in the range of 700-780nm to the total photons is 31.78%.

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