Processing method for improving aroma quality in white tea withering process

Abstract

The application provides a processing method for improving aroma quality in the withering process of white tea, and belongs to the technical field of tea processing. The processing method comprises the following steps: picking tea tree fresh leaves, and withering at room temperature; when the moisture content of the withered leaves is reduced to 65%-70%, using a blunt micro-needle to precisely physically wound the surface of the leaves; continuing to wither at room temperature after wounding and regularly turning over; finally, producing white tea through initial baking, water returning, re-baking and cooling. By introducing controllable physical damage in the middle period of withering, the application effectively activates endogenous glycosidase and other enzyme systems in tea leaves, promotes the hydrolysis and conversion of terpene, aldehyde ketone and other aroma precursors, significantly enhances the floral, fruity, sweet and mellow aroma of white tea without adding exogenous substances and relying on expensive equipment, and can induce the production of characteristic aroma components such as East Beauty tea. The method is simple in process, low in cost and easy to popularize, and is suitable for large-scale production of high-aroma white tea.

Description

Technical Field

[0001] This invention belongs to the field of tea processing technology, specifically a processing method for improving the aroma quality of white tea during the withering process. Background Technology

[0002] White tea, with its fresh, sweet, and delicate aroma, is highly favored by consumers, and its aroma is a core indicator determining its quality and commercial value. Previous research has found that moderate mechanical damage and biological stress can effectively induce the biosynthesis of endogenous aroma substances in tea leaves. In the oolong tea processing system, practitioners use unique withering techniques to control the aroma of summer and autumn teas, which are originally weak in aroma, to create a rich and full-bodied fragrance. This technical approach mainly includes two core stress methods: one is mechanical damage, such as shaking and rolling processes; the other is biological stress strategies, such as the use of leafhoppers to pierce and suck the fresh leaves of tea trees in Oriental Beauty tea, which induces the generation and accumulation of aroma substances in the tea leaves. In traditional white tea processing, withering, as a key processing step, mainly relies on natural spreading to achieve moisture loss, and the core process only revolves around adjusting the basic physical state. However, modern white tea processing adds auxiliary processes such as temperature and humidity control during the withering stage to optimize subsequent reaction conditions; and to avoid damage to the raw materials, a resting buffering process is added after withering. However, under this type of processing technique, the aroma quality of white tea mainly depends on the material basis of the tea tree variety itself, rather than the process control of withering. Moreover, the traditional withering process has a very low contribution to activating endogenous enzymatic reactions and enhancing aroma.

[0003] In recent years, although some progress has been made in the processing technology to improve the aroma quality of tea, the following problems still exist: (1) Although the aroma of tea can be enriched by scenting with exogenous flavorings or aromatic plants, the aroma substances do not originate from the tea itself. Improper control can easily mask the inherent flavor of the tea. At the same time, the purchase and processing of exogenous raw materials will increase the processing cost, which is not conducive to large-scale application. (2) Although the withering environment can be optimized by controlling the temperature and humidity of the equipment, the purchase and maintenance costs of professional equipment are high, which is difficult for small and medium-sized tea enterprises to bear. Moreover, the operation of the equipment requires professional technicians, which further increases the processing cost and makes it difficult to promote it widely in the industry. (3) Prolonging the withering time to promote the accumulation of aroma requires a large number of withering tanks or withering spaces, which is not conducive to the large-scale circulation and processing of raw materials during the tea season. Therefore, it is necessary to develop new processing techniques for the withering stage. By adding minor physical damage treatment during the withering process, the enzymatic and biochemical reactions of the tea leaves can be fully activated without damaging the appearance of the white tea, inducing the natural generation of aroma substances and enhancing its sweet and mellow taste. This ensures the natural safety of the tea, significantly reduces processing costs, is simple to operate without complicated equipment, and is easier to promote and apply in various tea companies, thereby better obtaining high-aroma tea quality from the tea leaves themselves. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a processing method for improving the aroma quality of white tea during the withering process. This method can make full use of various enzymatic and biochemical reactions of the withered leaves of tea trees to induce the production of a large amount of aroma substances, thereby better obtaining high-aroma tea quality from the tea itself.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a processing method for improving the aroma quality of white tea during the withering process, comprising the following steps: Fresh tea leaves are picked and withered at room temperature. When the moisture content of the withered leaves drops to 65%-70%, the surface of the withered leaves is damaged. The withered leaves after damage treatment continue to wither at room temperature until the moisture content drops to 18%-22%, and then dried to obtain white tea.

[0006] Preferably, the injury treatment is performed by puncturing with a blunt needle with a tip diameter of 0.25-0.3 mm.

[0007] More preferably, the puncture wound density is 3-5 wounds / cm². 2 The insertion depth is ≤0.3mm.

[0008] More preferably, the needle pitch of the blunt-tipped needle is 5mm × 5mm.

[0009] Preferably, the standard for picking fresh leaves is one bud and two leaves to one bud and three leaves.

[0010] Preferably, in an environment of 20-25℃ and 70%-80% relative humidity, the continued room temperature withering time is 36-42 hours.

[0011] Preferably, the drying steps include initial drying, rehydration, and re-drying; the initial drying temperature is 90-100℃ and the time is 8-12 min; the rehydration time is 120-150 min; and the re-drying temperature is 90-100℃ and the time is 15-20 min.

[0012] This invention provides a highly aromatic white tea, prepared by the above-described processing method.

[0013] This invention discloses a processing method for enhancing the aroma quality of white tea during the withering process. First, fresh tea leaves of uniform maturity are picked and evenly spread on ventilated drying racks for withering at room temperature. When the moisture content drops to 65%-70%, the surface of the withered leaves undergoes minor physical damage treatment. Withering continues at room temperature for 36-42 hours, and finally, the tea is dried to obtain high-quality white tea. This method, by adding a single, precise puncture technique during the withering stage, activates the activity of multiple enzyme systems within the withered leaves, strengthens enzymatic biochemical reactions, induces the tea's own stress response, and enriches aroma substances such as terpenes, aldehydes, and ketones. This significantly enhances the floral, fruity, and sweet aromas of the white tea, resulting in a rich, pure, and intense aroma. Compared with existing technologies, this invention has the following beneficial effects: (1) This invention effectively activates key endogenous enzyme systems such as β-glucosidase within the withered leaves by introducing controllable micro-physical damage during the mid-withering process, thereby strengthening the enzymatic biochemical reaction network centered on glycoside hydrolysis. This process requires no exogenous flavorings or additives, but rather induces the transformation of aroma precursors within the tea leaves themselves. Experimental data confirm that the aroma scores of tea samples treated by the method of this invention are significantly higher than those of the traditional process control. GC-MS analysis further shows that the total volatile matter content of the treated tea samples is higher, and the generation of unique aroma substances such as 2,6-dimethyl-3,7-octadien-2,6-diol (a characteristic aroma component of Oriental Beauty tea) is successfully induced, demonstrating a fundamental improvement in aroma quality from a material perspective. In addition, biochemical component analysis shows that the soluble sugar and reducing sugar content of the treated tea samples are significantly higher than those of the control, while the content of potential bitter components such as tea polyphenols and caffeine is reduced, leading to an increase in the phenol-to-amino acid ratio. This change in composition is directly reflected in the sensory characteristics of "sweet and mellow" flavor. The sweetness and harmony of the tea soup are significantly optimized, and the aroma and flavor are synergistically enhanced.

[0014] (2) Compared with the traditional process that relies on long-term natural withering, the present invention achieves efficient accumulation of aroma substances within a standard processing cycle (48 hours) through active physical intervention, avoiding the increased risk of mold and defect rate due to prolonged withering time.

[0015] (3) Compared with white tea processed by temperature and humidity control and colored light, the white tea produced by this invention has a richer and stronger aroma. This is because the physical damage treatment during the withering stage can activate the activity of a variety of enzyme systems in the withered leaves, strengthen the enzymatic biochemical reaction, induce the tea's own stress response and enrich aroma substances such as terpenes, aldehydes and ketones, so that the floral and fruity aroma and sweet aroma of white tea are significantly enhanced, and the aroma is rich, pure and rich.

[0016] (4) Compared with white tea processed by controlling the withering environment through precise temperature and humidity control equipment, the white tea produced by this invention has more practical and promotional value. This is because the puncture treatment during the withering stage does not require investment in expensive equipment. Simple physical operations can activate the enzyme activity in the withered leaves, making the white tea have a rich and pure aroma. At the same time, the cost of equipment purchase, maintenance and energy consumption is greatly reduced. The operation does not require professional technicians and is more suitable for various tea enterprise production scenarios. The processing efficiency and cost advantages are prominent.

[0017] (5) Compared with white tea processed by extending the withering time, the white tea produced by the present invention has a better aroma quality because the puncture treatment during the withering stage does not require extra time and effort. It only activates the activity of various enzyme systems in the withered leaves through physical means, inducing the tea leaves to produce a stress response, which significantly enhances the floral and fruity aroma and sweet aroma of the white tea, and the aroma is rich, pure and strong. At the same time, the processing cycle is shorter and the cost is lower, and it does not depend on environmental conditions, and the quality stability and natural safety are more prominent. Attached Figure Description

[0018] Figure 1 Figure showing the results of moderate treatment for minor physical damage to the surface of wilted leaves; Figure 2 Sensory evaluation images of white tea samples; Figure 3 Micrographs of different puncture treatments; A in the figure is an untreated leaf, B is a puncture-treated leaf of 2mm×1mm, and C is a puncture-treated leaf of 5mm×5mm. Figure 4 Comparison of volatile matter determination results for different groups of white tea by GC-MS; Figure A is a Venn diagram showing the number of volatile matter measured; Figure B shows the comparison of the relative content (μg / kg) of volatile matter components; Figure C shows the relative percentage (%) of volatile matter components. Figure 5 To determine the relative content of dominant aroma compounds in white tea samples by GC-MS. Detailed Implementation

[0019] This invention provides a processing method for improving the aroma quality of white tea during the withering process, wherein the processing method preferably includes the following steps: Fresh tea leaves are picked and withered at room temperature. When the moisture content of the withered leaves drops to 65%-70%, the surface of the withered leaves is damaged. The withered leaves after damage treatment continue to wither at room temperature until the moisture content drops to 18%-22%, and then dried to obtain white tea.

[0020] One of the core processes of this invention is to perform a single, precise physical damage to the surface of the withered leaves when their moisture content drops to 65%-70%. This step aims to slightly disrupt the leaf epidermal cells in a controlled manner, triggering a stress response in the tea leaves and activating endogenous enzyme systems, while avoiding irreversible mechanical damage to the overall structure of the tea leaves. In this invention, "moisture content" refers to the percentage of water mass in the withered leaves relative to their current total mass (fresh weight). For example, a 70% moisture content means that 100 grams of withered leaves contain 70 grams of water and 30 grams of dry matter. In practice, a calibrated rapid tea moisture meter can be used to perform non-destructive testing on representative withered leaf samples, directly reading the moisture content value. After withering begins, the leaf moisture content in representative spreading areas should be monitored regularly. Once the monitoring data shows that the average moisture content of at least three different sampling points enters the 65%-70% range, surface damage treatment for the entire batch should be arranged immediately. Preferably, this is performed when the moisture content is approximately 68%-70%, at which point the leaf condition is most ideal.

[0021] In this invention, the withering environment is characterized by a temperature of 20-25°C and a relative humidity of 70%-80%. This mild and stable withering environment is a prerequisite for ensuring that fresh leaves can uniformly and predictably reach the critical physical damage treatment stage of a moisture content of 65%-70%. In specific embodiments of this invention, during cold seasons, the temperature can be maintained by closing doors and windows and using heating equipment; during hot seasons, cooling is required by turning on exhaust fans, evaporative cooling pads, or air conditioning. When humidity is too low, air humidity can be increased by sprinkling water on the ground, placing damp cloths, or using ultrasonic humidifiers; when humidity is too high, ventilation and dehumidification need to be strengthened, or a dehumidifier needs to be turned on. In practical implementation, the airflow and speed of the withering trough can be adjusted to ensure smooth air circulation within the withering space and avoid excessive local temperature and humidity differences.

[0022] In this invention, the initial water content of fresh leaves is typically around 75%-78%. When the water content drops to 65%-70%, the cells experience a moderate decrease in turgor pressure due to water loss, and the permeability of the cell membrane and vacuolar membrane begins to selectively increase, while the organelle structure remains relatively intact. At this point, when puncturing the leaf, the cell contents (enzymes and substrates) mix and react more easily near the injury site, while avoiding excessive sap loss that might have occurred initially due to overly full cell structures. Simultaneously, at this water content, the leaf's flexibility reaches its optimal state. It retains sufficient toughness to withstand a precise puncture of 0.3 mm without easily breaking, yet becomes softer than a fresh leaf due to moderate water loss, facilitating even force application with a blunt needle and the formation of controllable micro-wounds.

[0023] In this invention, the damage treatment uses a blunt-tipped needle with a preferred tip diameter of 0.25-0.3 mm for puncture; more preferably, the tip diameter is 0.28 mm. This needle tip diameter range ensures sufficient mechanical strength, preventing bending or breakage during operation; it also generates a sufficiently effective physical stimulus signal to reliably disrupt the cell wall integrity and initiate enzymatic reactions. Furthermore, the aforementioned needle tip diameter range ensures a small wound. An excessively thick needle tip can lead to an overly large wound, potentially causing excessive sap leakage, accelerated non-enzymatic browning, and even localized leaf necrosis, which is detrimental to the elegant formation of aroma compounds and affects the appearance of the finished tea.

[0024] In this invention, the core of the damage treatment lies in the precise quantitative control of the spatial distribution and vertical scale of the damage. In this invention, the preferred puncture density is 3-5 punctures / cm². 2 More preferably 4 per cm 2 This means that in any representative area of ​​the leaf (avoiding the midrib), there should be an average of 3 to 5 independent puncture points per square centimeter of leaf area. This density is usually achieved by controlling the needle-tip spacing of the puncture tool. As a preferred embodiment, a needle spacing of 5mm × 5mm is used, resulting in a density of approximately 4 punctures / cm². 2 This parameter showed optimal performance in sensory evaluation and aroma component analysis. The superficial cells of the epidermis and palisade tissue of withered white tea leaves are key areas for the storage of aroma precursors (such as bound glycosides) and the distribution of enzyme systems. In this invention, the insertion depth is preferably ≤0.3 mm. This depth is sufficient to ensure that the blunt needle tip penetrates the epidermal stratum corneum and epidermal cell walls, releasing cell contents and promoting enzyme-substrate contact, thereby initiating reactions such as glycoside hydrolysis. Simultaneously, it avoids rapid and disordered exudation of large amounts of sap, ensuring the localization and controllability of the damage.

[0025] In this invention, the preferred needle spacing of the blunt-tipped needles is 5mm × 5mm. In actual production, to improve efficiency, multiple blunt-tipped needles conforming to the above specifications are usually arranged and fixed on a substrate at equal intervals of 5mm × 5mm to form a microneedle array or puncture roller. This array density, after calculation, can achieve a target density of approximately 4 puncture points per square centimeter.

[0026] In this invention, the preferred standard for picking fresh leaves is one bud and two to one bud and three leaves. This invention uses one bud and two or three leaves, which are both sufficiently flexible to withstand precise punctures to a depth of 0.3 mm without easily breaking, and possess sufficient structural integrity to withstand uniform micro-damage and support subsequent withering for tens of hours. Leaves that are too young are easily damaged during puncture, while leaves that are too old may be less responsive to stimulation. This invention's fresh leaf picking standard ensures that the finished tea has excellent tenderness and freshness while achieving a richer aroma potential and higher raw material utilization, making the method of this invention more commercially viable.

[0027] In this invention, the wilted leaves, after being physically punctured, are further wilted at room temperature until their moisture content drops to 18%-22% (by weight). When the moisture content is within this range, the leaf cell structure is sufficiently softened but not dried out. The activity and substrate concentration of intracellular enzymes, especially β-glucosidase activated by the puncture, tend to decrease, and product accumulation reaches its peak. Simultaneously, moderate water tension is conducive to the formation and accumulation of volatile aroma components, rather than their premature loss. As the moisture content drops to 18%-22%, the leaves exhibit typical signs of moderate wilting: the leaf color changes from green to dark green or grayish-green, the leaf margins droop noticeably, the midrib becomes supple due to water loss, the leaves feel soft to the touch but are not sticky, and the overall aroma changes from grassy to a sweet or slightly floral / fruity fragrance. This physical state can serve as a rapid auxiliary diagnostic criterion.

[0028] In this invention, as a further preferred embodiment, wilting is carried out at 20-25°C and 70%-80% relative humidity for 36-42 hours. In this mild and stable environment, the rate of water loss from the punctured leaves is optimally matched with the rate of enzymatic reactions. The continuous wilting treatment time of 36-42 hours provides sufficient time for the endogenous enzyme system, such as β-glucosidase, activated by the puncture, ensuring that most of the bound aroma precursors are fully hydrolyzed and converted into free terpenes, aldehydes, ketones, and other volatile aroma substances. This time range is inherently consistent with the physical endpoint of water content decreasing to 18%-22%. Under the aforementioned standard conditions, the time required for the punctured leaves to naturally lose water from approximately 65-70% to 18-22% is between 36-42 hours. Therefore, this time range can serve as an important process guidance parameter under known and controlled environmental conditions, and is particularly suitable for large-scale production in environments with stable wilting facilities.

[0029] In this invention, the drying step preferably includes a segmented precision drying process comprising three stages: initial drying, rehydration, and final drying. This process aims to efficiently remove moisture and fix quality while maximizing the preservation and optimization of the rich aroma and mellow sweetness formed during the withering stage (especially after physical damage induction). The initial drying temperature is preferably 90-100℃, and the time is preferably 8-12 minutes. Immediately after the highly aromatic leaves have withered, a short-term treatment at a relatively high temperature is performed. The core purpose is to rapidly inhibit the activity of enzymes such as polyphenol oxidase and peroxidase, which may lead to quality deterioration, and to terminate excessive enzymatic oxidation, thereby locking in the optimal aroma and flavor base formed during the withering stage. Simultaneously, some surface water and some internal water are rapidly evaporated, allowing the tea leaves to initially take shape. The rehydration time is preferably 120-150 minutes. The key to this rehydration stage is not continued water loss, but rather the redistribution of residual moisture within the tea leaves to achieve internal and external balance. Under heat, slow non-enzymatic reactions continue to occur within the tea leaves, which helps develop a more mellow flavor and further volatilizes undesirable low-boiling-point odors such as grassy smells. The preferred re-drying temperature is 90-100℃, and the preferred time is 15-20 minutes. After achieving moisture balance, a final drying process is carried out again at a suitable temperature. This re-drying stage aims to thoroughly reduce the moisture content to the safe storage standard of the finished white tea product and further heat-fix the developed aroma and flavor.

[0030] This invention provides a highly aromatic white tea, prepared by the above-described processing method.

[0031] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0032] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available products.

[0033] Example 1 A processing method for improving the aroma quality of white tea during the withering process, comprising the following steps: (1) Fresh leaf picking: Fresh tea leaves are picked according to the standard of one bud and two leaves or one bud and three leaves; (2) Withering of tea leaves at room temperature: Spread the freshly picked leaves evenly on a ventilated drying rack for withering at room temperature; (3) Treatment of puncture wounds on the surface of wilted leaves: Spread the wilted leaves evenly at room temperature. When the moisture content of the wilted leaves drops to 70%, use a blunt-tipped needle with a needle tip diameter of 0.28 mm to perform a micro-needle array with a needle spacing of 5 mm × 5 mm to perform a minor physical damage treatment on the surface of the wilted leaves. Control the puncture density to 4 micro-holes per square centimeter, and control the puncture depth to 0.3 mm. Each puncture should be precise and the force should be light to avoid causing bud breakage or leaf damage (e.g., Figure 1 (as shown) (4) Further wilting: Continue to wilt the punctured leaves at room temperature, turning them over regularly, until the leaf moisture content drops to about 20%; (5) Drying: The tea is dried using a dryer. First, it is initially dried at 100℃ for 10 minutes on the fast setting. After cooling, it is rehydrated for 120 minutes. Then, it is re-dried at 100℃ for 20 minutes on the fast setting. Finally, it is cooled to room temperature to obtain white tea.

[0034] Example 2 A processing method for improving the aroma quality of white tea during the withering process, comprising the following steps: (1) Fresh leaf picking: Fresh tea leaves are picked according to the standard of one bud and two leaves or one bud and three leaves; (2) Withering of tea leaves at room temperature: Spread the freshly picked leaves evenly on a ventilated drying rack for withering at room temperature; (3) Treatment of puncture wounds on the surface of wilted leaves: spread the wilted leaves evenly at room temperature. When the moisture content of the wilted leaves drops to 65%, use a blunt needle with a needle tip diameter of 0.28 mm to perform a micro-needle array with a needle spacing of 5 mm × 5 mm to perform a small physical damage treatment on the surface of the wilted leaves. Control the puncture density to 4 micro-holes per square centimeter, and control the puncture depth to 0.3 mm. The puncture should be precise and the force should be light so as not to cause bud breakage or leaf damage. (4) Further wilting: Continue to wilt the punctured leaves at room temperature, turning them over regularly, until the leaf moisture content drops to about 20%; (5) Drying: The tea is dried using a dryer. First, it is initially dried at 100℃ for 10 minutes on the fast setting. After cooling, it is rehydrated for 120 minutes. Then, it is re-dried at 100℃ for 20 minutes on the fast setting. Finally, it is cooled to room temperature to obtain white tea.

[0035] Comparative Example 1 A method for processing white tea (1) Fresh leaf picking: Fresh tea leaves are picked according to the standard of one bud and two leaves or one bud and three leaves; (2) Withering of tea leaves at room temperature: Spread the freshly picked leaves evenly on a ventilated drying rack or withering trough for withering at room temperature for 48 hours; (3) Drying: The tea is dried using a dryer. First, it is initially dried at 100℃ for 10 minutes on the fast setting. After cooling, it is rehydrated for 120 minutes. Then, it is re-dried at 100℃ for 20 minutes on the fast setting. Finally, it is cooled to room temperature to obtain white tea.

[0036] Comparative Example 2 Unlike Example 1, a blunt needle with a tip diameter of 0.28 mm was used to make punctures at a depth of 2 mm × 1 mm (approximately 25 punctures / cm). 2 The microneedle array with needle spacing performs minor physical damage treatment on the surface of wilted leaves, while the other steps remain unchanged.

[0037] Comparative Example 3 Unlike Example 2, a blunt needle with a tip diameter of 0.28 mm was used to make punctures at a depth of 2 mm × 1 mm (approximately 25 punctures / cm). 2 The microneedle array with needle spacing performs minor physical damage treatment on the surface of wilted leaves, while the other steps remain unchanged.

[0038] Sensory evaluation in Experiment Example 1 A sensory evaluation team of 15 members (8 women and 7 men) who had received more than 3 months of aroma training was invited to conduct quality evaluation on the white tea samples prepared in Examples 1-2 and Comparative Examples 1-3 in accordance with the national standard for sensory evaluation of tea (GB / T23776-2018), focusing on three aspects: liquor color, aroma, and taste. The evaluation results were taken as mean ± standard deviation.

[0039] From Table 1 and Figure 2 The results show that Examples 1 and 2 treated using the method of the present invention are significantly superior to those treated using the traditional process in terms of both aroma and taste, the two key quality factors. Figure 3 A). Of particular note is Example 1, which exhibited the highest overall quality score (91 points), displaying a rich, elegant complex of floral and fruity sweetness, and a sweet, full-bodied flavor. Conversely, the excessively high puncture density treatment ( Figure 3 Compared to Comparative Example 2 (B), it exhibited an unpleasant "camphor odor" and had the lowest overall score. This fully demonstrates the effectiveness of the specific damage treatment employed in this invention. Figure 3 C) It is crucial for the targeted induction of elegant floral fragrance and the prevention of quality deterioration.

[0040] Table 1 Comparison of Sensory Evaluation and Scoring Results of White Tea Samples

[0041] Experimental Example 2 Routine biochemical component analysis was performed on the white tea samples from Examples 1-2 and Comparative Example 1: (1) Theanine: The determination method is in accordance with GB / T 23193-2017 "Determination of Theanine in Tea"; (2) Amino acids: The determination method is in accordance with GB / T8314-2013 "Determination of total free amino acids in tea"; (3) Tea polyphenols: The determination method refers to GB / T8313-2018 "Determination method of tea polyphenols and catechins in tea"; (4) Caffeine: GB / T 8312-2013 "Determination of Caffeine in Tea" was adopted; (5) Total sugar: anthrone-sulfuric acid colorimetric method was used; (6) Soluble sugars: anthrone-sulfuric acid colorimetric method was used; (7) Reducing sugars: The anthrone-sulfuric acid colorimetric method was used.

[0042] The biochemical composition analysis results in Table 2 show that, compared with Comparative Example 1, the contents of amino acids, total sugars, theanine, and tea polyphenols in Examples 1 and 2 decreased, while the contents of soluble sugars and reducing sugars increased. Specifically, the contents of tea polyphenols and caffeine in Example 2 decreased significantly, while the contents of soluble sugars and reducing sugars increased significantly. This suggests that Examples 1 and 2 exhibited improved sweetness and reduced bitterness, resulting in significantly better sweetness and harmony in the tea soup.

[0043] Table 2. Comparative analysis results of biochemical components in white tea samples.

[0044] Note: Different lowercase letters in the same column indicate significant differences (P<0.05).

[0045] Experimental Example 3 The volatile substances in the white tea samples prepared in Example 1, Example 2 and Comparative Example 1 were detected and analyzed using HS-SPME-GC-MS gas chromatography-mass spectrometry.

[0046] A total of 111 volatile compounds were identified in three types of white tea. Data on the aroma compounds in the dry tea showed that after minor mechanical damage treatment, unpleasant odor compounds such as cis-2-pentenol and 1-tetradecyl alcohol disappeared in Comparative Example 1, while the content of floral aroma compounds such as linalool, trans-nerolidol, nerol, phenylethyl alcohol, geraniol, and methyl salicylate increased in Examples 1 and 2. Simultaneously, some new aroma compounds were formed in both examples, including floral compounds such as (E,E)-2,4-heptadienal, grapeol, and trans-3-hexenoic acid, as well as fresh fruity compounds such as methyl heptenone and geraniic acid. Furthermore, teas treated under different moisture content conditions produced their own unique aroma compounds, thus exhibiting different styles. Figure 4Results A showed that Example 1 produced 16 unique aroma components, among which ethyl palmitate, trans-2-hexenol, 5-ethyl-6-methylhepta-3-en-2-one, 2-hexenal, 2,6-dimethyl-3,7-octadien-2,6-diol, and 2,4-hexadiene collectively exhibited a rich fruity aroma. Notably, 2,6-dimethyl-3,7-octadien-2,6-diol is a characteristic aroma compound of Oriental Beauty tea, which is renowned for its excellent and unique floral and fruity aroma. This indicates that the treatment in Example 1 helps white tea generate the characteristic aroma components of Oriental Beauty tea, thereby promoting the formation of a high-floral-fruity white tea. Example 2 produced two unique aroma compounds, α-terpineol and (-)-α-penicillinene, both exhibiting floral characteristics. Furthermore, previously unpleasant acidic substances such as hexanoic acid and tartaric acid disappeared, and the content of nonanoic acid also decreased. This indicates that the treatment in Example 2 helps to form a white tea with a mellow and pleasant floral aroma.

[0047] Aroma molecules from three white tea samples were classified and analyzed to obtain... Figure 4 A comparison of the composition ratios of white tea aromas, from... Figure 4 B. Figure 4 C and Figure 5 The results show that the total content of aroma components in Examples 1 and 2, especially the proportion of floral and fruity aroma components such as alcohols and aldehydes, is significantly higher than that in Comparative Example 1. In Example 1, the content of aldehydes and heterocyclic compounds such as linalool oxide is more prominent. While all three examples maintain a similar component proportion structure, with alcohols as the core aroma component, the relative content of alcohols and esters closely related to floral and fruity aromas is higher in Examples 1 and 2. These components typically correspond to the sensory expression of fresh fruity and elegant floral aromas. In teas such as black tea, methyl salicylate is one of the auxiliary components constituting its floral and fruity aroma and fresh base aroma. It works synergistically with substances such as geraniol and linalool to enrich the aroma layers of tea. In white tea, the content of methyl salicylate significantly increases after minor mechanical damage. In conclusion, it is clear that the richness and intensity of floral and fruity aromas in Examples 1 and 2 are superior to those in Comparative Example 1.

[0048] In summary, the tea leaves used in this invention, after undergoing appropriate surface micro-physical damage treatment during the withering stage, can stimulate stress responses such as glycosidase hydrolysis in the withered leaves. This induces the tea leaves' own stress response and enriches them with aroma substances such as terpenes, aldehydes, and ketones. After sufficient withering and drying, fresh leaves from common tea varieties can be processed at different withering stages according to preference, thereby producing white teas with different styles, high floral and fruity aromas, and significantly enhanced sweetness and mellowness. Compared with traditional white tea processing techniques, the quality of withered leaves is significantly improved, and the aroma of the tea leaves is better preserved while maintaining the same processing cycle, resulting in better tea quality and flavor. This process is simple and controllable, requires no exogenous additives, is low in cost, and effectively enhances the aroma quality of the tea leaves themselves, possessing high practical value and promising prospects for promotion.

[0049] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A processing method for improving the aroma quality of white tea during the withering process, characterized in that, Includes the following steps: Fresh tea leaves are picked and withered at room temperature. When the moisture content of the withered leaves drops to 65%-70%, the surface of the withered leaves is damaged. The withered leaves after damage treatment continue to wither at room temperature until the moisture content drops to 18%-22%, and then dried to obtain white tea.

2. The processing method according to claim 1, characterized in that, The injury treatment was performed by pricking with a blunt-tipped needle with a tip diameter of 0.25-0.3 mm.

3. The processing method according to claim 2, characterized in that, The density of puncture wounds is 3-5 per cm³. 2 The insertion depth is ≤0.3mm.

4. The processing method according to claim 2, characterized in that, The blunt-tipped needle has a needle spacing of 5mm × 5mm.

5. The processing method according to claim 1, characterized in that, The standard for picking fresh leaves is one bud and two leaves to one bud and three leaves.

6. The processing method according to claim 1, characterized in that, Under an environment of 20-25℃ and 70%-80% relative humidity, the continued room temperature withering time is 36-42 hours.

7. The processing method according to claim 1, characterized in that, The drying steps include initial drying, rehydration, and re-drying; the initial drying temperature is 90-100℃ and the time is 8-12 min; the rehydration time is 120-150 min; and the re-drying temperature is 90-100℃ and the time is 15-20 min.

8. A highly aromatic white tea, prepared by the processing method described in any one of claims 1-7.

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