Rosa roxburghii tratt summer and autumn broken black tea and making method thereof

Abstract

The invention relates to the technical field of tea, in particular to roxburgh rose summer and autumn broken black tea and a making method thereof. The preparation method comprises the following steps: rolling and cutting fresh leaves of summer and autumn tea, adding roxburgh rose juice into the rolled and cut leaves, and uniformly mixing; fermenting under the conditions that the temperature is 22-26 DEG C and the relative humidity is more than 90%; the fermentation time is 30 to 60 minutes; after fermentation, drying to obtain the rosa roxburghii tratt summer and autumn broken black tea; wherein the mass ratio of the roxburgh rose juice to the rolled and cut leaves is 5-25%. According to the method, the comprehensive quality of the summer and autumn broken black tea can be remarkably improved by adding the roxburgh rose juice before fermentation.

Description

Technical Field

[0001] This invention relates to the field of tea technology, specifically to a prickly pear summer and autumn black tea and its preparation method. Background Technology

[0002] Tea is one of the world's three major non-alcoholic beverages. In recent years, with social progress and scientific development, people have paid more attention to tea and tea drinks. Drinking tea is beneficial to health. Summer and autumn tea leaves account for 55%-60% of the total annual tea production, but compared with spring tea, they have a coarser and weaker aroma and a bitter taste, resulting in low resource utilization of summer and autumn tea. Because the quality of summer and autumn tea is relatively poor compared with spring tea, with a strong bitter taste and insufficient aroma, its economic benefits are low and its resource utilization rate is not high.

[0003] Therefore, it is necessary to further improve the quality of summer and autumn teas and develop their potential value. Summary of the Invention

[0004] This invention provides a prickly pear summer and autumn black tea and its preparation method. Adding prickly pear juice before fermentation can significantly improve the overall quality of the summer and autumn black tea.

[0005] A method for preparing prickly pear summer and autumn black tea includes:

[0006] Fresh summer and autumn tea leaves are shredded and crushed, and prickly pear juice is added to the shredded leaves and mixed evenly. Fermentation is carried out at a temperature of 22-26℃ and a relative humidity of over 90% for 30-60 minutes. After fermentation, the leaves are dried to obtain prickly pear summer and autumn black tea. The prickly pear juice accounts for 5%-25% of the mass of the shredded leaves.

[0007] Specifically, before the rolling and cutting, the process includes a step of withering the fresh summer and autumn tea leaves; the withering is outdoor sun withering: time 15-20 minutes, temperature 30-42℃ (preferably 36-41℃), relative humidity 35-42% (preferably 40%); or, the withering is indoor withering: time 15-18 hours (preferably 18 hours), temperature 25-34℃, relative humidity 45%-60%.

[0008] Specifically, the prickly pear juice accounts for 5%-20% of the mass of the chopped leaves.

[0009] Specifically, the prickly pear juice and the chopped leaves are in a mass ratio of 5%, 10%, 15%, 20%, or 25%.

[0010] Specifically, the fresh leaves of the summer and autumn tea consist of one bud and two or three leaves.

[0011] In some embodiments, the summer and autumn tea leaves are raw materials of tea leaves grown locally in Anshun.

[0012] Specifically, during fermentation, the leaves are spread out to a thickness of 4-6 cm and turned over every 10-15 minutes.

[0013] The summer and autumn tea of ​​this invention refers to tea leaves that are harvested and processed in the summer and autumn seasons (July-August) after the spring tea picking season.

[0014] Specifically, the prickly pear juice is obtained by washing the prickly pear, juicing it under low temperature conditions, and filtering it; wherein, the low temperature environment refers to: temperature 5-8℃ (preferably 8℃), relative humidity 70-75% (preferably 75%).

[0015] The prepared prickly pear juice can be stored at 4°C (refrigerator).

[0016] The prickly pear (Rosa roxburghii Tratt) described in this invention is a plant belonging to the genus Rosa in the family Rosaceae.

[0017] Experiments show that when the ratio of prickly pear juice to the chopped leaves is 10%, the prepared prickly pear summer and autumn black tea has a brighter color, a higher aroma, and higher sensory evaluation scores for color and aroma; when the ratio of prickly pear juice to the chopped leaves is 5%, the prepared prickly pear summer and autumn black tea has a more mellow taste and a higher sensory evaluation score for taste; when the ratios of prickly pear juice to the chopped leaves are 10% and 20%, the sensory evaluation scores are higher, and the scores are comparable.

[0018] Experiments show that adding prickly pear juice during fermentation can increase the water extract content of summer and autumn broken black tea, resulting in a richer tea soup and a more complex flavor. The water extract content of summer and autumn broken black tea is highest when the prickly pear juice accounts for 15% of the weight of the rolled leaves.

[0019] Experiments show that adding prickly pear juice during fermentation can increase the polyphenol content of summer and autumn broken black tea, thereby improving its antioxidant properties. The highest polyphenol content was observed in the summer and autumn broken black tea when the prickly pear juice content was 15% of the weight of the rolled leaves.

[0020] Experiments show that adding prickly pear juice during fermentation can significantly reduce the caffeine content of summer and autumn broken black tea, thereby reducing bitterness. The caffeine content of summer and autumn broken black tea is lowest when the prickly pear juice accounts for 20% of the weight of the rolled leaves.

[0021] Experiments show that adding prickly pear juice during fermentation can increase the catechin and theaflavin content of summer and autumn broken black tea, thereby improving its antioxidant properties. The highest catechin content was observed in the summer and autumn broken black tea when the prickly pear juice accounted for 20% of the weight of the rolled leaves.

[0022] Experiments show that adding prickly pear juice during fermentation can improve the antioxidant properties of summer and autumn broken black tea. The antioxidant properties of summer and autumn broken black tea are highest when the ratio of prickly pear juice to the weight of the rolled leaves is 20%.

[0023] Experiments have shown that adding prickly pear juice during fermentation can enhance the aroma of summer and autumn broken black tea. This aroma specifically includes 53 volatile components found in broken black tea.

[0024] The present invention also provides a prickly pear summer and autumn red tea prepared by the method.

[0025] This invention uses fresh summer and autumn tea leaves as raw materials, and adds prickly pear juice to the kneaded leaves before fermentation to prepare prickly pear summer and autumn broken black tea. Results show that the exogenous addition of prickly pear juice can improve the sensory quality, antioxidant capacity, and aroma quality of broken black tea. Attached Figure Description

[0026] Figure 1 This is a graph showing the DPPH free radical scavenging rate of tea samples in Experiment 1 of this invention.

[0027] Figure 2 This is a graph showing the content of volatile components in Experiment 1 of the present invention.

[0028] Figure 3 This is a graph showing the percentage of volatile substances in Experiment 1 of this invention. Detailed Implementation

[0029] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0030] With regard to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0031] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0032] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This application specification and embodiments are merely exemplary.

[0033] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0034] Unless otherwise specified, the technical solutions described in this invention are all conventional solutions in the field, and the reagents or raw materials used are all purchased from commercial channels or are publicly available unless otherwise specified.

[0035] Example 1

[0036] This embodiment provides a prickly pear summer and autumn black tea, the preparation method of which is as follows:

[0037] After washing the prickly pear, juice it at a low temperature of 8℃ and 75% relative humidity, then filter it to obtain prickly pear juice.

[0038] Summer and autumn tea leaves (one bud and two or three leaves) are withered, rolled, and chopped. Prickly pear juice is added to the rolled leaves and mixed thoroughly. Fermentation is carried out at a temperature of 22-26℃ and a relative humidity of over 90% for 60 minutes. After fermentation, the leaves are dried to obtain prickly pear summer and autumn black tea. The prickly pear juice accounts for 5% of the total weight of the rolled leaves. The withering is carried out indoors for 18 hours at a temperature of 34℃ and a relative humidity of 60%.

[0039] Example 2

[0040] This embodiment provides a prickly pear summer and autumn black tea, the only difference between its preparation method and that of Embodiment 1 is that the prickly pear juice and the mass ratio of the kneaded leaves is 10%.

[0041] Example 3

[0042] This embodiment provides a prickly pear summer and autumn black tea, the only difference between its preparation method and that of Embodiment 1 is that the prickly pear juice and the mass ratio of the kneaded leaves is 15%.

[0043] Example 4

[0044] This embodiment provides a prickly pear summer and autumn black tea, the only difference between its preparation method and that of Embodiment 1 is that the prickly pear juice and the mass ratio of the kneaded leaves is 20%.

[0045] Example 5

[0046] This embodiment provides a prickly pear summer and autumn black tea, the only difference between its preparation method and that of Embodiment 1 is that the prickly pear juice and the mass ratio of the kneaded leaves is 25%.

[0047] Comparative Example 1

[0048] This comparative example provides a prickly pear summer and autumn black tea, the only difference between its preparation method and that of Example 1 is that prickly pear juice is not added.

[0049] Experiment 1

[0050] 1 Experimental Methods

[0051] 1.1 Preparation of Prickly Pear Juice

[0052] After washing the prickly pear, juice it at a low temperature (8℃, 75% humidity), filter it, and store it at 4℃.

[0053] 1.2 Preparation of Prickly Pear Summer and Autumn Broken Black Tea

[0054] The fresh tea leaves used in this experiment were local Anshun tea leaves (one bud and two or three leaves), harvested in August 2024 from Haibatang Tea Factory, Pingba District, Anshun City, Guizhou Province. The prickly pears were purchased from Xiahewan Village, Xiayun Town, Anshun City, Guizhou Province.

[0055] Fresh leaves were uniformly withered: sun-withered for 15-20 minutes at 40.9℃ and 40.3% relative humidity outdoors, and indoor withered for 18 hours at 25-34℃ and 45%-60% relative humidity indoors. The leaves were then uniformly rolled and cut into five equal portions. Prickly pear juice was added to the rolled leaves at a ratio of 0%, 5%, 10%, 15%, and 20% by weight, and mixed thoroughly. The rolled leaves were then placed in a fermentation machine for fermentation at 22-26℃ and above 90% relative humidity, with a leaf thickness of 4-6 cm. The leaves were turned every 10 minutes for a total fermentation time of 60 minutes. After fermentation, the leaves were dried to obtain a control group. Tea sample information is shown in Table 1 below.

[0056] Table 1 Tea Sample Information

[0057] serial number Tea sample information CK Tea without added prickly pear juice Comparative Example 1 A1 Add 5% prickly pear juice tea sample after kneading and cutting, before fermentation. Example 1 A2 Add 10% prickly pear juice tea sample after kneading and cutting, before fermentation. Example 2 A3 Add 15% prickly pear juice tea sample after kneading and cutting, before fermentation. Example 3 A4 Add 20% prickly pear juice tea sample after kneading and cutting, before fermentation. Example 4

[0058] 2. Detection Methods

[0059] 2.1 Sensory evaluation

[0060] The sensory evaluation of black tea samples with different concentrations of prickly pear juice was conducted in accordance with GB / T 23776-2018 "Sensory Evaluation Methods for Tea". The evaluation team consisted of six sensory evaluators with professional backgrounds, who evaluated the five tea samples from five aspects: appearance, liquor color, aroma, taste, and infused leaf appearance.

[0061] 2.2 Determination of internal components

[0062] The content of water extract was determined according to the method of GB / T 8305-2013 "Determination of Water Extract in Tea"; the content of caffeine was determined according to GB / T 8311-2013 "Determination of Caffeine in Tea - High Performance Liquid Chromatography"; the total free amino acid content was determined according to GB / T 8314-2013 "Determination of Total Free Amino Acids in Tea"; the content of tea polyphenols was determined according to GB / T 8313-2018 "Detection Method of Tea Polyphenols and Catechins in Tea"; and the content of theaflavins was determined according to GB / T 30483-2013 "Determination of Theaflavins in Tea - High Performance Liquid Chromatography".

[0063] 2.3 Determination of DPPH free radical scavenging rate

[0064] Take 2 mL of 2×10 -4 2 mL of sample was mixed with mol / L DPPH-ethanol solution, shaken thoroughly, and reacted at room temperature in the dark for 30 min. The sample was then centrifuged at 7000 rpm for 5 min, and the absorbance of the supernatant was measured at 517 nm. The same method was used to add 2 mL of ethanol to 2 mL of DPPH-ethanol solution and measure the absorbance at 517 nm. Similarly, 2 mL of sample solution was added to 2 mL of ethanol and the absorbance was measured at 517 nm. Vitamin C was used as a positive control. Each experiment was repeated in triplicate. The DPPH free radical scavenging rate of the tea infusion was calculated using a formula, and the IC50 of the DPPH free radical scavenging rate was obtained using SPSS software to evaluate the antioxidant capacity of the tea.

[0065] Reference: Zhang, Yufeng. Extraction of protein from selenium-enriched konjac and its antioxidant activity. Wuhan: Huazhong University of Science and Technology, 2019.

[0066] 2.4 Aroma component determination

[0067] The volatile components were determined by GC-MA, referring to the method of Ai Antao et al.

[0068] References: Ai Antao, Chen Xi, Li Yanli, et al. Analysis of aroma components of different varieties of "Zunyi Hong" black tea [J]. Journal of Food and Biotechnology, 2023, 42(04):103-111.

[0069] Extraction method: Accurately weigh 4.0 g of tea powder into a 100 mL headspace vial, place the rotor inside, add 3 g of NaCl and 40 mL of boiled pure water, and then seal the headspace vial. Place the sample vial on a heated magnetic stirrer and equilibrate at 80 °C for 6 min. Insert the manual SPME handle directly into the sample vial, push out the extraction head, allow adsorption for 50 min, then remove it. Next, insert the manual SPME handle into the gas chromatograph (GC) injection port and desorb at 260 °C for 5 min, while simultaneously starting the instrument to collect data.

[0070] GC-MS method: GC conditions: HP-5MS flexible quartz capillary column (30m×0.25mm, 0.25μm); Temperature program: initial temperature 40℃, hold for 2 min, then increase to 100℃ at 7℃ / min, hold for 1 min, increase to 170℃ at 5℃ / min, hold for 1 min, increase to 230℃ at 5℃ / min, hold for 1 min, increase to 260℃ at 9℃ / min, total run time 42.9 min; Carrier gas: high-purity helium, purity ≥99.999%; Carrier gas flow rate: 1.0 mL / min; Injector temperature: 260℃; Injection mode: splitless injection.

[0071] MS conditions: EI source, electron energy 70 eV; interface temperature 280℃, ion source temperature 230℃, quadrupole temperature 150℃; emission current 35.2 μA; scan mode: full scan; scan range: m / z 40–400; solvent delay time: 3.75 min.

[0072] Preliminary retrieval and manual analysis of chromatographic peak information obtained from GC-MS analysis were performed using the NIST11 standard spectral library, and retention indices were calculated using the retention times of C5–C40 n-alkanes.

[0073] R = 100n + 100 × (t) a -t n ) / (t n+1 ×t n )

[0074] In the formula: R is the retention index of aroma substances; t a t n t n+1 The retention time (in minutes) of the peak elution of the analyte and the mixed standard of n-alkanes with carbon numbers between n and n+1.

[0075] Then, based on relevant literature, the mass fraction of each aroma component was calculated according to the peak area reduction method.

[0076] 2.5 Data Processing and Analysis

[0077] The data was organized and analyzed using Excel, SPSS, and other related software.

[0078] 3 Results and Analysis

[0079] 3.1 Sensory evaluation results of prickly pear black tea

[0080] The sensory evaluation results are shown in Table 2. The quality of the fruit-flavored broken black tea obtained by adding prickly pear juice before fermentation differed in the five evaluation items: In terms of appearance, all five samples maintained the typical physical properties of broken black tea, namely, the tea leaves had sharp tips, the dry tea was dark brown with visible white hairs, and contained a suitable amount of single leaves. This indicates that the addition of prickly pear juice did not damage the basic morphological structure of the tea leaves. In terms of liquor color, A2, A3, and A4 are brighter than A1, and A1 is brighter than CK. The liquor color scores are in the following order: A2 = A3 > A1 = A4 > CK. Regarding aroma, CK and A2 have a rough, grassy aroma, A2 has a floral aroma and a high aroma level, and A3 and A4 have a prickly pear fruit aroma. The aroma scores are in the following order: A2 = A4 > A3 > CK = A1. In terms of taste, A4 is more mellow than A2 and A3, A2 and A3 have added "fruity characteristics" compared to CK, and A1 is fresh and mellow. The taste scores are in the following order: A1 > A4 > A2 > CK > A3. Looking at the tea leaves, all five samples have a reddish-brown color, but the tea samples with added prickly pear juice have brighter leaves than CK, reflecting a more complete pigment conversion during fermentation. Overall, the scores are in the following order: A2 = A4 > A3 > A1 > CK.

[0081] Table 2 Sensory Evaluation Form

[0082]

[0083] 3.2 Analysis of the components of prickly pear black tea

[0084] The water extract content is a comprehensive reflection of the tea's ability to dissolve its internal substances. The higher the water extract content, the more concentrated and flavorful the tea soup is usually. Table 3 shows that the water extract content of the tea samples ranged from 34.59% to 38.54%, with CK having the lowest and A3 the highest. Amino acids are the main umami quality components, with the highest content in the tender buds and leaves of tea shoots, decreasing as leaf maturity increases. During the fermentation of black tea, some amino acids are converted. As the addition of prickly pear juice to the tea samples reduced the amino acid content, the amino acid content of CK, A1, and A2 showed a slight increase, while the amino acid content of A3 and A4 decreased to 2.66% and 2.37%, respectively. Tea polyphenols are an important component of tea flavor, and their content is closely related to the flavor, color, and antioxidant capacity of tea. The data shows that the overall tea polyphenol content of the tea samples did not change significantly, ranging from 14.02% to 14.50%, with CK having the lowest tea polyphenol content at 14.02% and A3 having the highest at 14.50%.

[0085] Table 3. Biochemical test results of tea samples

[0086]

[0087] Note: The data in the table are the mean ± standard deviation of three replicates. Different letters in the same column indicate significant differences (p < 0.05).

[0088] Table 4 reveals the following analysis: Caffeine (CAF) is the main flavor compound in tea; higher caffeine content results in a more bitter and astringent tea. Summer and autumn teas have higher caffeine content than spring teas. From CK to A4, the caffeine content decreases with increasing concentration of prickly pear juice, dropping from 3.44% to 3.20%. Catechins are an important class of polyphenolic compounds in tea, belonging to the flavanols, and are one of the main sources of bitterness and health benefits in tea. Their content, composition, and transformation in tea directly affect its taste, color, and nutritional value. The trend shows that the catechin content generally increases with the increase of prickly pear juice concentration. The total content of catechins increased from 0.82% in the lowest CK group to 1.06% in the highest A4 group. EGCG content increased continuously with the proportion of prickly pear juice, from 0.37% to 0.60%, while ECG and EGCG increased simultaneously from 0.22% to 0.36%. Theaflavins produced by black tea fermentation are important substances that determine quality. Theaflavins (TF) are important factors in the brightness, freshness, and intensity of black tea soup. The data in the table show that the A1, A2, A3, and A4 theaflavin content of the prickly pear juice group is higher than that of the CK group. TF3G and TFDG were detected in the 5%, 15%, and 20% groups, indicating that prickly pear juice may promote the formation of specific theaflavins.

[0089] Table 4. Results of determination of caffeine, catechins, and theaflavins in tea samples.

[0090]

[0091] 3.3 Antioxidant Capacity Analysis

[0092] DPPH radicals are stable nitrogen-centered free radicals and are an important indicator of a sample's antioxidant capacity. The DPPH scavenging effect under the experimental conditions is as follows: Figure 1 As shown, all five tea samples exhibited a certain degree of DPPH free radical scavenging effect. Within a certain concentration range, the DPPH free radical scavenging rate of all five samples increased with increasing concentration. Within the mass concentration range of 0.1–1.0 mg / ml, the DPPH free radical scavenging rates of CK, A1, A2, A3, and A4 were 21.00%–84.00%, 26.00%–85.00%, 30.00%–88.00%, 35.00%–92.00%, and 39.00%–95.00%, respectively. The DPPH free radical scavenging rate of the tea samples increased with increasing concentration of prickly pear juice.

[0093] In DPPH free radical scavenging experiments, IC50 specifically refers to the concentration of the analyte (antioxidant) required to scaveng (or inhibit) 50% of DPPH free radicals. A lower IC50 value means that a lower concentration is needed to scavenge 50% of DPPH free radicals. This directly indicates that the substance has a stronger, more efficient, and more potent free radical scavenging ability. Conversely, a higher IC50 value means a higher concentration is needed to achieve a 50% scavenging rate, indicating that the substance's antioxidant capacity is relatively weak. Table 5 shows that A4 has the strongest antioxidant capacity among the five tea samples, while CK has the weakest. The antioxidant capacity of the tea samples increases with the addition of prickly pear juice. The antioxidant capacity of the five tea samples, ranked from strongest to weakest, is as follows: A4 > A3 > A2 > A1 > CK.

[0094] Table 5 IC50 values ​​of DPPH free radical scavenging rate in tea samples

[0095]

[0096] 3.4 Analysis of Volatile Components in Prickly Pear Broken Tea

[0097] 3.4.1 Analysis of the content and proportion of different aroma types

[0098] The content of different volatile components in different tea samples was determined by detection. There were a total of 53 volatile components in the five types of broken black tea. According to their chemical structure, they were divided into seven categories: alcohols, aldehydes, hydrocarbons, terpenes, ketones, esters and other (heterocyclic compounds). Among them, there were 19 alcohols, 10 aldehydes, 2 hydrocarbons, 8 terpenes, 5 ketones, 7 esters and other (heterocyclic compounds) 2.

[0099] Of the five broken black tea samples, the total volatile matter content was 64510.90 μg / kg for CK, 86733.35 μg / kg for A1, 76268.44 μg / kg for A2, 64047.28 μg / kg for A3, and 50363.29 μg / kg for A4. Figure 2 and Figure 3 The results show that alcohols account for the largest proportion of total volatile substances, ranging from 52.66% to 58.61%, while hydrocarbons account for the smallest proportion, ranging from 0.27% to 0.73%. Figure 2 It can be seen that the content of alcohols, aldehydes, esters, and other substances in A1 is significantly higher than that in the other four tea samples, while the content of ketones, although not significantly different, is still slightly higher than that in the other four samples. Secondly, through... Figure 3It can be seen that the alcohol content in CK is higher than that in the four CTC black tea samples with added prickly pear juice, but there is no significant difference in the alcohol content among the four experimental tea samples. However, in terms of the proportion of other substances, the tea samples with added prickly pear juice have a significantly higher proportion of other substances than CK. This means that alcohols are the main components of the aroma of black tea, accounting for 19.38% to 86.68% of the total aroma of the tested black teas. Alcohol compounds usually have distinctive floral and fruity aromas, and their variety and relative content are relatively high in various teas. Esters usually exhibit fruity aromas, while ketones generally have sweet and floral-fruity aromas. These three relatively high-content substances collectively endow the floral-fruity and sweet aroma characteristics of floral-fruity black tea, consistent with the aroma evaluation and scoring results in the sensory evaluation.

[0100] 3.4.2 Analysis of different types of volatile components

[0101] (1) Analysis of volatile components of alcohols

[0102] Volatile alcohols are one of the core components of tea aroma, with compounds possessing high aroma activity values ​​among them. As shown in Table 6, among the 19 alcohols, geraniol, linalool, trans-nerolidol, phenylethyl alcohol, and dehydrolinalool have the highest content in that order. Geraniol has floral, rose, and citrus aromas, while linalool is a hallmark component of black tea, exhibiting a unique lily-of-the-valley aroma. Trans-nerolidol is a relatively mild aroma component with a sweet floral and fruity fragrance. These aroma compounds give broken black tea its unique floral and fruity aromas, increasing its freshness and fruitiness, and adding a unique prickly pear flavor to summer and autumn broken black tea.

[0103] (2) Analysis of volatile components of aldehydes

[0104] Aldehydes are volatile compounds that are not only the core source of the freshness and invigoration of tea aroma, but also important contributors to complex aromas such as floral, fruity, and roasted notes. Table 6 shows that A1, trans-2-hexenal (green leaf aldehyde), had the highest content, and the trans-2-hexenal content in tea samples with added prickly pear juice was significantly higher than that in the control group (CK). Benzaldehyde has a nutty aroma, trans-2-hexenal (green leaf aldehyde) has a strong grassy aroma, and geraniol, one of the two main geometric isomers of citral, has a lemony aroma. These aroma compounds give broken black tea its freshness and invigoration, as well as unique nutty and fruity flavors.

[0105] (3) Analysis of volatile components of hydrocarbons

[0106] Two hydrocarbons were detected in this study: n-tetradecane and 2,3,5,8-tetramethyl-decane. As shown in Table 6, the n-tetradecane content was significantly higher in A2 (421.60 ug / kg) and lowest in A1 (89.25 ug / kg). The CK (catchment group) had a slightly higher n-tetradecane content than A3 but slightly lower than A4. The content of 2,3,5,8-tetramethyl-decane decreased with increasing prickly pear juice concentration. Due to the large molecular weight, low volatility, and lack of polar functional groups of long-chain alkanes, their interaction with olfactory receptors is weak. Based on the carbon chain structure of n-tetradecane and 2,3,5,8-tetramethyl-decane, it can be inferred that these two compounds are almost odorless and tasteless. However, their core value lies in their chemical inertness and low odor characteristics, making them ideal solvents, carriers, or analytical standards, rather than contributors to aroma.

[0107] (4) Analysis of volatile components of terpenes

[0108] Table 6 shows that the ocimene content in the experimental groups A1-A4 with added prickly pear juice was higher than that in the control group (CK), with A1 having the highest content and A3 the second highest. Furthermore, the (E)-β-farnesene content in A and A2 was significantly higher than that in CK, but A3 had the lowest (E)-β-farnesene content at 190.86 ug / kg. Table 6 also shows that α-farnesene, Δ-juniperene, 2-camphene, and ocimene were present in relatively large proportions. α-farnesene has a sweet fruity aroma (apple, banana) and floral notes; Δ-juniperene has a dry woody, smoky, and herbal aroma, enhancing aroma persistence; 2-camphene has a pine woody aroma, citrus peel aroma, and a spicy note; and ocimene's aroma characteristics are grassy, ​​floral, and sweet citrus notes, giving the tea a fresh initial note. These volatile terpenes provide sweet, floral, and woody aromas to the broken black tea, resulting in a unique fragrance.

[0109] (5) Analysis of volatile components of ketones

[0110] Ketones play an irreplaceable core role in the aroma of tea. In the analysis of volatile ketones in broken black tea with prickly pear juice added before fermentation (Table 6), the contents of isomethyl-α-ionone and jasmone first increased and then decreased with increasing prickly pear juice concentration, with β-ionone having the highest content among the five tea samples. Isomethyl-α-ionone has a rich, sweet floral aroma with a distinct balsamic, powdery, and jam-like sweetness; β-ionone has violet and raspberry floral aromas; and jasmone has jasmine floral and sweet aroma components. In the aroma of broken black tea, volatile ketones neutralize the grassy smell, enhance the sweetness and mellowness, and make the aroma more layered.

[0111] (6) Analysis of volatile components of esters

[0112] Among the volatile esters in broken black tea with prickly pear juice added before fermentation, methyl salicylate was the most abundant ester compound detected. The levels of methyl salicylate in A1, A2, and A3 were significantly higher than in the control (CK), but the level in A4 was lower. The second most abundant ester was hexanoic acid leaf ester. Methyl palmitate contributes to its rich floral and fruity aroma, while methyl salicylate has almond, fruity, and minty wintergreen notes, contributing to the tea's fresh and fruity aroma. Also known as wintergreen oil, it is an ester compound with a wintergreen leaf aroma. Its unique wintergreen leaf aroma can blend with the aroma of the black tea itself, creating a rich and complex fragrance. Hexanoic acid leaf ester adds plum and fruity notes. These volatile esters contribute floral and fruity aromas to the broken black tea, enriching its overall fragrance.

[0113] (7) Analysis of other volatile components

[0114] Among other volatile substances in broken black tea with prickly pear juice added before fermentation, the content of cis-linalool oxide increased from 3724.72 μg / kg to 5483.24 μg / kg (A1) with increasing prickly pear juice concentration, and then decreased to a minimum of 1953.88 μg / kg (A4). The content of trans-linalool oxide (CK) was significantly lower than that of the tea sample with added prickly pear juice, with the highest content in A1 (5814.87 μg / kg), which decreased with increasing concentration. Cis-linalool oxide has a fresh, grassy aroma, while trans-linalool oxide is characterized by a sweet woody and floral aroma. These two heterocyclic compounds are key aroma components of tea, imparting woody and floral notes to broken black tea.

[0115] Table 6 Aroma components of different tea samples

[0116]

[0117]

[0118]

[0119] Note: Data in the table are the mean ± standard deviation of three replicates. Different letters in the same column indicate significant differences (p < 0.05). 4. Discussion and Conclusion

[0120] This study produced broken black tea by adding different concentrations of prickly pear juice before fermentation. Sensory evaluation, compound analysis, DPPH free radical scavenging rate determination, and volatile aroma component analysis were then conducted. The results showed that A4, the tea sample with 20% prickly pear juice added before fermentation, had the best overall quality, achieving the highest sensory evaluation score of 87.40. Furthermore, it showed superior performance compared to other tea samples in terms of component content. Caffeine content decreased from 3.44% in the control group (CK) to 3.20% in A4, reducing bitterness and astringency, resulting in a more mellow taste. A4 had the highest total theaflavins content (0.17%). Theaflavins are key indicators of the brightness and freshness of black tea, indicating that prickly pear juice promoted their formation. Secondly, A4 had the lowest IC50 value, indicating the strongest antioxidant capacity. Regarding aroma components, A4 had higher levels of fruity components such as terpenes and esters, resulting in a prominent fruity aroma.

[0121] 4.1 Effects of different concentrations of prickly pear juice on the sensory quality of summer and autumn broken black tea

[0122] Sensory evaluation revealed that the summer and autumn broken black tea with added prickly pear juice before fermentation performed better in aroma, taste, and leaf appearance than the tea without added prickly pear juice. Specifically, the aroma was enhanced with floral and fruity notes; the taste was more mellow with the added prickly pear flavor; and the leaf appearance showed a significantly brighter reddish-brown color compared to the control (CK), reflecting improved pigment conversion efficiency during fermentation. This trend was consistent with the significantly higher A3 (38.54%) and A4 (36.56%) water extract content (Table 3) compared to the CK (34.59%), indicating that prickly pear juice promoted the dissolution and transformation of substances within the tea leaves. Through a dual pathway of biochemical transformation and physical aroma enhancement, prickly pear juice transformed the "roughness and astringency" of summer and autumn broken black tea into a quality highlight of "floral and fruity aroma and mellow taste," providing key technological support for the high-value utilization of resources.

[0123] Black tea fermentation is a process centered on the oxidation of polyphenolic compounds. Catechins are enzymatically oxidized to form theaflavins, thearubigins, and theabrownins, and promote the coupled oxidation of amino acids, carotene, and other compounds to form aroma compounds, resulting in the unique flavor of black tea. Prickly pear is rich in highly active polyphenol oxidase (PPO), with an optimal pH of 5.0–5.5, which closely matches the fermentation environment of black tea (pH 4.5–5.5). This enzyme specifically catalyzes the oxidation of ortho-phenolic hydroxyl groups of catechins (especially ester-type catechins EGCG and ECG) to quinone intermediates, thereby promoting theaflavin synthesis through two pathways. Pathway 1: Prickly pear PPO catalyzes the oxidation of ester-type catechins (such as EGCG and ECG) to quinone intermediates, which then polymerize with unoxidized catechins to form TF-1, TF-2, etc. Data shows that the EGCG content increased from 0.37% in the control group (CK) to 0.60% in the apricot juice concentration, while the ECG content increased from 0.22% to 0.36%, providing sufficient substrate for theaflavins synthesis. Pathway 2: Quinone intermediates couple with gallic acid to form TF-3 (theaflavins-3'-gallate), consistent with the detection results of theaflavins derivatives in A1-A4. Furthermore, summer and autumn teas have higher polyphenol content (14.02%-14.50%) and PPO activity than spring teas, forming a synergistic effect with prickly pear PPO, resulting in the highest polyphenol content (14.50%) in A3, further promoting the oxidative polymerization reaction. Due to the differences in growing climate conditions and seasonal physiological characteristics of tea trees between spring tea and summer / autumn tea, the content of tea polyphenols and the activity of polyphenol oxidase (PPO) in summer / autumn tea are significantly higher than those in spring tea. Therefore, the above analysis shows that adding prickly pear juice can improve the theaflavin conversion rate of summer / autumn broken black tea, thereby further enhancing the brightness and freshness of the tea soup.

[0124] 4.2 Effects of different concentrations of prickly pear juice on the antioxidant capacity of summer and autumn broken black tea

[0125] The antioxidant capacity of five tea samples was systematically evaluated by measuring DPPH free radical scavenging rate and calculating IC50 values. The results showed that with increasing prickly pear concentration, the IC50 values ​​of the prickly pear black tea were all lower than the control tea. Among them, tea sample A4 exhibited the strongest antioxidant activity, with an IC50 value of 0.19 mg / mL, significantly lower than the other tea samples. This indicates that tea sample A4 has a higher efficiency in scavenging DPPH free radicals, meaning that only a lower concentration is needed to achieve a 50% free radical scavenging effect.

[0126] From the perspective of antioxidant capacity ranking, the antioxidant capacity of the five tea samples, from strongest to weakest, is A4 > A3 > A2 > A1 > CK. This ranking clearly reflects the impact of prickly pear juice addition on the antioxidant capacity of summer and autumn broken black tea. The addition of prickly pear juice triggers a series of complex physiological and biochemical reactions during fermentation. The polyphenols and highly active polyphenol oxidases abundant in prickly pear synergistically interact with catechins and other components in tea leaves in the fermentation environment of black tea (pH 4.5-5.5). Polyphenol oxidase catalyzes the oxidation of catechins to form quinone intermediates, thereby promoting the synthesis of antioxidant active ingredients such as theaflavins. At the same time, the addition of prickly pear juice significantly increases the total amount of catechins, especially key antioxidant components such as EGCG and ECG. The polyphenols in prickly pear themselves also have a strong free radical scavenging ability, which synergistically enhances the antioxidant capacity of the tea samples with the antioxidant components in tea leaves.

[0127] These results clearly demonstrate that adding an appropriate concentration of prickly pear juice before fermentation can significantly enhance the antioxidant activity of summer and autumn broken black tea. This provides strong theoretical support for the high-value utilization of summer and autumn tea, and also offers new ideas and methods for developing new black tea products with stronger antioxidant functions.

[0128] 4.3 Effects of different concentrations of prickly pear juice on the aroma of summer and autumn broken black tea

[0129] The aroma of black tea originates from the fresh leaves themselves and is formed during processing. Processing is an external factor that causes the transformation or accumulation of quality components in tea, and it is also an important means of forming or improving the quality of black tea. This study, based on a new tea processing method, explored the effects of different concentrations of prickly pear juice on the quality of summer and autumn broken black tea. Analysis of the evaluation results shows that compared with traditional summer and autumn broken black tea (CK), tea samples with added prickly pear juice before fermentation exhibit two significant changes: firstly, the aroma is enhanced with prickly pear fruit and floral notes; secondly, the taste is more mellow and carries a prickly pear fruit flavor (sweetness and a slight astringency). In conclusion, the addition of prickly pear juice gives broken black tea a more fresh and sweet aroma and taste, improving its sensory quality.

[0130] In terms of total volatile matter content, both A1 and A2 had higher total volatile matter content than CK, with A1 having the highest content at 86733.35 ug / kg, a 34.00% increase compared to CK (64510.90 ug / kg). Regarding aroma characteristics, for the floral and fruity compounds linalool, geraniol, and methyl salicylate, the contents of these three compounds in A1 increased by 77.00%, 16.00%, and 12.00% respectively compared to CK. Analysis of the data suggests that adding prickly pear juice provides appropriate amounts of terpene precursors, such as linalool and geraniol, and esterification substrates. The substance, methyl salicylate, generates a floral-fruity aroma complex through enzymatic reaction, effectively masking the raw, grassy smell of summer and autumn teas. For jasmine ketone A3, which has a jasmine aroma, the content increased significantly by 154.00% compared to the control (CK). For trans-2-hexenal (green leaf aldehyde), which has a fresh, green aroma, the A1 content reached 2739.67 ug / kg, 14.80 times that of the CK. These substances form a "floral-fruity aroma" complex through enzymatic oxidation and esterification, effectively masking the raw, grassy smell of summer and autumn teas, which is highly consistent with the sensory evaluation of "high and long-lasting aroma." Data analysis leads to the conclusion that adding a certain concentration of prickly pear juice can significantly improve the aroma quality of summer and autumn broken black tea.

[0131] Through a dual mechanism of "enzymatic oxidation and aroma reconstruction," prickly pear juice transforms the disadvantages of summer and autumn teas—high in tea polyphenols and strong in bitterness—into the quality advantages of "high in theaflavins and prominent floral and fruity aromas." Data shows that when the prickly pear juice addition was 20.00% (A4), the tea sample achieved the highest overall score (87.40 points), with optimal levels of antioxidant capacity, the variety (53 types) of aroma substances, and their content. This provides a quantitative basis for the high-value utilization of summer and autumn tea resources. This technological approach not only improves tea quality but also provides theoretical support for the cross-sectoral integration of the prickly pear industry and the tea industry, demonstrating significant economic and ecological benefits.

[0132] This study shows that adding prickly pear juice before fermentation not only improves the utilization rate of summer and autumn tea, but also increases the internal components and aroma substances in the tea, enhances the antioxidant capacity of the tea sample, and improves the quality of the tea. This provides a new direction for the high-value utilization of summer and autumn tea, namely, improving the bitterness of summer and autumn tea by adding prickly pear juice from the outside.

[0133] Although the present invention has been described in detail above with general descriptions, specific embodiments, and experiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for producing prickly pear summer and autumn black tea, characterized in that, include: Fresh summer and autumn tea leaves are shredded and crushed, and prickly pear juice is added to the shredded leaves and mixed evenly. Fermentation is carried out at a temperature of 22-26℃ and a relative humidity of over 90% for 30-60 minutes. After fermentation, the leaves are dried to obtain prickly pear summer and autumn black tea. The prickly pear juice accounts for 5%-25% of the mass of the shredded leaves.

2. The method for preparing prickly pear summer and autumn black tea according to claim 1, characterized in that, Before the rolling and cutting, the process also includes a step of withering the fresh summer and autumn tea leaves; the withering is outdoor sun withering: time 15-20 minutes, temperature 30-42℃, relative humidity 35-42%; or, the withering is indoor withering: time 15-18 hours, temperature 25-34℃, relative humidity 45%-60%.

3. The method for preparing prickly pear summer and autumn black tea according to claim 1 or 2, characterized in that, The weight ratio of prickly pear juice to the chopped leaves is 5%-20%.

4. The method for preparing prickly pear summer and autumn black tea according to any one of claims 1-3, characterized in that, The weight ratio of prickly pear juice to the chopped leaves is 5%, 10%, 15%, 20%, or 25%.

5. The method for preparing prickly pear summer and autumn black tea according to any one of claims 1-4, characterized in that, The fresh leaves of the summer and autumn tea are one bud and two or three leaves.

6. The method for preparing prickly pear summer and autumn black tea according to any one of claims 1-5, characterized in that, During fermentation, the leaves are spread to a thickness of 4-6 cm and turned over every 10-15 minutes.

7. The method for preparing prickly pear summer and autumn black tea according to any one of claims 1-6, characterized in that, The prickly pear juice is obtained by washing the prickly pear, juicing it under low temperature conditions, and then filtering it; wherein, the low temperature environment refers to a temperature of 5-8℃ and a relative humidity of 70-75%.

8. The prickly pear summer and autumn red tea prepared by the method according to any one of claims 1-7.

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