Fresh and sweet flower fragrance type Maojian and making method thereof

Abstract

The invention relates to the technical field of tea processing, in particular to fresh and sweet flower fragrance type Maojian tea and a making method thereof. The fresh and sweet flower fragrance type Maojian is prepared by the method. The method comprises the following steps: selecting materials; tedding, wherein intermittent hot air treatment is adopted; performing fixation, namely performing fixation at the temperature of 205-225 DEG C for 3 minutes; rolling, and controlling the cell breakage rate of the rolled leaves to be 60-70% and the strip forming rate to be 78-83%; making strips; and performing post-treatment to obtain the fresh and sweet flowery Maojian tea. The fresh and sweet flower fragrance type Maojian tea which is short in tedding time and short in production cycle and ingeniously integrates fresh and sweet taste and unique flower fragrance can be prepared.

Description

Technical Field

[0001] The invention relates to the technical field of tea processing, and in particular to a fresh and sweet floral-scented Maojian tea and a preparation method thereof. Background Art

[0002] Compared with other types of tea, green tea retains the natural substances in the fresh leaves to the greatest extent, especially nutrients such as tea polyphenols and caffeine, which makes it have distinctive characteristics in taste and efficacy.

[0003] The production process of green tea mainly includes the steps of spreading, withering, rolling, and drying. Among them, the spreading step gradually reduces the moisture content of the fresh leaves and inhibits cellular metabolic activity, which manifests as physical changes such as slower respiration rate, wilting and softening of the leaves, and darkening of color. At the same time, it is accompanied by the volatilization of grassy substances and the generation of fragrant substances, laying a suitable physical foundation for subsequent processing. The withering step uses high temperature to quickly destroy the enzyme activity in the fresh leaves and prevent the oxidation of tea polyphenols, thereby ensuring that the quality characteristics of green tea, such as clear soup, green leaves, and fresh taste, are preserved. Rolling is to shape the appearance of the tea leaves, promote the seepage of tea juice, and enhance the taste of the tea. The drying process is used to further remove moisture from the tea leaves to facilitate storage and subsequent brewing.

[0004] Green tea is a rich and diverse category, encompassing many renowned varieties such as West Lake Longjing and Biluochun. Guzhang Maojian also holds a prominent position within the green tea landscape. Produced in Guzhang County, Xiangxi, Hunan Province, where high mountains, dense forests, and shrouded in mist create a uniquely favorable natural environment for tea cultivation, Guzhang Maojian boasts a compact, round, and straight shape, with a slender tip, covered in white hairs, and a lustrous emerald green color. Its aroma is characterized by a long-lasting chestnut fragrance, a rich and mellow flavor, a bright yellow-green liquor, and even, tender green leaves.

[0005] While the traditional Guzhang Maojian tea production process has been passed down through generations, there's still room for further exploration in the pursuit of innovative taste and quality improvement. In the green tea quality evaluation system, flavor and aroma are core sensory indicators, accounting for 30% and 25% of the weighting, respectively. During the transformation and upgrading process, developing fresh, sweet, and floral-scented green teas has become a key focus to meet the growing demand for high-quality green tea among the younger generation of consumers aged 18-35. This new type of green tea cleverly blends a fresh, sweet flavor with a unique floral aroma, not only satisfying consumers' craving for a delicious taste but also enriching the tea's aroma with a richer, more complex flavor profile. This new type of green tea is expected to stand out in the market and propel the green tea industry into a new stage of development.

[0006] However, the production of Guzhang Maojian tea is mainly concentrated in the period from the Spring Equinox to the Grain Rain, when rainfall is frequent, resulting in a long time for the tea to spread out (e.g., 10 to 12 hours). In order to reduce the time for spreading out, shorten the production cycle, and cleverly combine the sweet taste with the unique floral fragrance, it is necessary to develop a sweet floral Maojian tea and its production method. Summary of the Invention

[0007] The present invention aims to provide a fresh and sweet floral Maojian and a production method thereof, and the specific technical solutions are as follows:

[0008] In a first aspect, the present invention provides a method for preparing fresh and sweet floral Maojian tea, comprising:

[0009] Step S1, selecting materials, selecting fresh tea leaves of Maojian tea with a single bud, one bud and one leaf, and / or one bud and two leaves, free of pests and diseases and mechanical damage as raw materials;

[0010] Step S2, spreading the fresh tea leaves, spreading them flat, and passing normal temperature air at room temperature until no water droplets are left on the surface of the fresh tea leaves; then, subjecting the fresh tea leaves to intermittent hot air treatment to obtain tea leaves after spreading; the hot air temperature used in the hot air treatment is 35-45°C, and the treatment time is 10-15 minutes; between each two adjacent hot air treatments, the tea leaves are allowed to stand for 30-35 minutes, and the tea leaves are turned over during the standing period;

[0011] Step S3, fixing, putting the tea leaves after spreading into a fixing machine for fixing, to obtain fixed leaves; the fixing temperature used in the fixing treatment is 205-225°C, and the fixing time is 3 minutes;

[0012] Step S4, rolling, after the withered leaves are cooled to room temperature, rolling to obtain rolled leaves; through the rolling process, the cell breakage rate of the rolled leaves is controlled to reach 60% to 70%, and the strip forming rate is 78% to 83%;

[0013] Step S5, making strips, breaking up the rolled leaves into pieces and then drying and shaping them; then spreading them to cool and rehydrate them, and then rolling them into strips to form straight tea leaves;

[0014] Step S6: After post-processing, fresh and sweet floral Maojian is obtained.

[0015] Optionally, in step S2, the surrounding environment is kept clean and ventilated during the spreading period.

[0016] Optionally, in step S2, the hot air treatment is performed at least twice.

[0017] Optionally, in step S3, the tea leaves put into the fixing machine have a flat thickness of 2 to 3 cm.

[0018] Optionally, in step S3, the withering process further includes turning the tea leaves.

[0019] Optionally, in step S5, the drying temperature used in the drying and shaping treatment is 80° C., and the drying time is 15 minutes; the moisture content of the tea leaves after the drying and shaping treatment is 30% to 35%.

[0020] Optionally, in step S5, the rate of forming straight tea leaves reaches more than 90%.

[0021] Optionally, in step S6, the post-treatment includes a primary baking treatment; the treatment temperature adopted in the primary baking treatment is 80° C., and the treatment time is 10 minutes; the moisture content of the tea leaves after the primary baking treatment is 12% to 20%.

[0022] Optionally, in step S6, the post-treatment includes a re-drying treatment after the initial baking treatment; the treatment temperature adopted in the initial baking treatment is 85°C and the treatment time is 60 minutes; the moisture content of the tea leaves after the initial baking treatment is 4% to 6%.

[0023] In a second aspect, the present invention provides a fresh and sweet floral-scented Maojian tea, which is produced by the method for producing the fresh and sweet floral-scented Maojian tea.

[0024] The application of the technical solution of the present invention has at least the following beneficial effects:

[0025] (1) The present invention provides a method for producing fresh and sweet floral Maojian, which can produce fresh and sweet floral Maojian with short spreading time, short production cycle and clever fusion of fresh and sweet taste and unique floral fragrance. Specifically, compared with the traditional spreading process parameters, that is, the spreading temperature is 25°C and the spreading time is 10h, the present invention adopts intermittent hot air to treat fresh tea leaves during the spreading process in step S2, and defines the corresponding process parameters, which not only allows the water in the tea leaves to evaporate quickly, the biochemical reaction process in the leaf cells is moderately accelerated, the spreading time is reduced, and the production cycle is shortened, but also can promote the rapid volatilization of low-boiling-point grassy substances in the tea leaves, overcoming the disadvantage of slow loss of green gas under traditional natural spreading; further, in the spreading process defined by the present invention, the activity of the enzyme is rapidly improved, the conversion efficiency of protein to amino acids is greatly increased, the content of free amino acids and soluble sugars is significantly increased, the ratio of simple catechins to ester-type catechins is improved, and the content of caffeine and tea polyphenols is reduced, laying a material foundation for the fresh and sweet taste. At the same time, due to the suitable temperature for spreading the tea leaves, more aroma precursors such as aldehydes and alcohols are generated, paving the way for the subsequent formation of a prominent floral aroma. Furthermore, compared to the traditional parameters for the tea leaf fixing process, which is a fixing temperature of 230°C, the fixing temperature used in the fixing process of step S3 of the present invention is 205-225°C, preferably 210°C. This can not only quickly inactivate the enzymes and terminate unnecessary oxidation reactions, but also accurately control the degree of oxidation of tea polyphenols, retaining more catechins and maintaining the freshness of the tea leaves. Moreover, under the fixing temperature conditions defined by the present invention, volatile components with floral aroma, such as methyl salicylate, indole, nerolidol, and cis-jasmone, can be better retained or generated, ultimately making the tea leaf's floral aroma prominent. Therefore, the present invention combines step S2 with step S3 to synergistically increase the fresh and sweet taste of the tea leaves and effectively retain the floral aroma substances.

[0026] (2) In step S4, the present invention uses a rolling process to control the cell fragmentation rate of the rolled leaves to 60% to 70%, so that the tea cells are fully broken, ensuring the fresh and sweet taste and floral aroma of the tea. If the cell fragmentation rate is too high, it may cause excessive oxidation and loss of the ingredients in the tea, making the taste of the tea bland and the aroma damaged. If the cell fragmentation rate is too low, the active ingredients in the tea cannot be fully released, which will affect the taste and aroma of the tea. The rolling process is used to control the stripping rate to 78% to 83%, which is used to lay the foundation for the next step of the stripping process, so that the rolled leaves have appropriate plasticity and toughness, which facilitates the smooth formation into tight and uniform straight strips during the subsequent drying, shaping and stripping process. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention are within the scope of protection of the present invention.

[0028] Example 1:

[0029] A method for preparing fresh and sweet floral-scented Maojian tea, comprising:

[0030] Step S1, selecting materials, selecting Maojian (Maojian variety is fresh Golden No. 1 variety, produced in Guzhang County, Xiangxi, Hunan) single buds and tender leaves with one bud and one leaf, and requiring fresh tea leaves that are plump, tender, free of pests and diseases, without red discoloration, and without mechanical damage as raw materials; during the process of picking and transporting the fresh tea leaves, use bamboo containers in appropriate amounts to protect them from sunlight, mechanical damage, heat, and red discoloration;

[0031] Step S2, spreading the fresh tea leaves, spreading the fresh tea leaves evenly in a withering tank, and passing air at room temperature (i.e., 25±5°C, specifically 25°C) through the tea leaves until no water droplets are removed from the surface of the fresh tea leaves; then, subjecting the fresh tea leaves to intermittent hot air treatment to obtain tea leaves after spreading; the hot air temperature used in the hot air treatment is 35-45°C (specifically 35°C), and the treatment time is 10-15 minutes (specifically 12 minutes); between each two adjacent hot air treatments, the tea leaves are allowed to stand for 30-35 minutes (specifically 33 minutes), and the tea leaves are turned over during the standing period to allow them to be evenly heated. At this time, the tea leaves can smell a rich floral fragrance;

[0032] Step S3, fixing, putting the tea leaves after spreading into a fixing machine for fixing, to obtain fixed leaves; the fixing temperature used in the fixing process is 205-225°C (specifically 210°C), and the fixing time is 3 minutes; wherein, the fixing temperature setting is closely related to the amount of leaves added, and if the amount of leaves added is large, the fixing temperature can be appropriately increased; the fixed leaves are placed in a special dustpan, and the tea leaves are gently rubbed and turned to reduce the surface temperature of the tea leaves, so as to prevent water vapor from being trapped in the tea leaves and generating unpleasant odors;

[0033] Step S4, rolling, after the withered leaves are cooled to room temperature, rolling is performed to obtain rolled leaves; the rolling is performed using a three-stage pressure method of "light-heavy-light"; through the rolling process, the cell breakage rate of the rolled leaves is controlled to reach 60% to 70%, and the strip forming rate is 80%;

[0034] Step S5, making strips, after the rolled leaves are deblocked, they are placed in a roaster for drying and shaping; then, they are spread out to cool and rehydrate, and then they are straightened and rolled three times to form straight strips of tea leaves;

[0035] Step S6: After post-processing, fresh and sweet floral Maojian is obtained.

[0036] In step S2, the surrounding environment is kept clean and ventilated during the spreading period to prevent the tea leaves from being contaminated by dust, impurities, etc.

[0037] In step S2, the hot air treatment is performed twice.

[0038] In step S3, the tea leaves put into the fixing machine have a flat thickness of 2 to 3 cm (such as 3 cm).

[0039] In step S3, the fixing process further includes turning the tea leaves.

[0040] In step S5, the drying temperature used in the drying and shaping treatment is 80° C. and the drying time is 15 minutes. The moisture content of the tea leaves after the drying and shaping treatment is 30% to 35%, and the leaves exhibit the physical characteristics of being prickly but bendable, and the tender stems being bent but not broken.

[0041] In step S5, the rate of forming straight tea leaves reaches above 90% (eg 92%).

[0042] In step S6, the post-treatment includes a primary baking treatment; the treatment temperature used in the primary baking treatment is 80°C and the treatment time is 10 minutes; the moisture content of the tea leaves after the primary baking treatment is 12% to 20%. At this time, the tea leaves show the characteristics of "enhanced prickliness, and tender stems that are easy to break".

[0043] In step S6, the post-treatment includes a re-drying treatment after the initial baking treatment; the treatment temperature used in the initial baking treatment is 85°C and the treatment time is 60 minutes; the moisture content of the tea leaves after the initial baking treatment is 4% to 6%, and the phenomenon of "pinching the tender stems into powder by hand" occurs.

[0044] Example 2:

[0045] Different from Example 1, the Maojian variety is the fresh Golden No. 2 variety, produced in Guzhang County, Xiangxi, Hunan.

[0046] Example 3:

[0047] The difference from Example 1 is that the Maojian variety is a fresh Castanopsis chinensis variety produced in Guzhang County, Xiangxi, Hunan.

[0048] Comparative Example 1:

[0049] Different from Example 1, step S2 is modified to spreading the fresh tea leaves evenly in the withering trough, and passing normal temperature (i.e. 25±5°C, specifically 25°C) air at room temperature (i.e. 25±5°C, specifically 25°C) for 10 hours; the withering temperature in step S3 is modified to 230°C.

[0050] Samples of the Maojian tea produced in Examples 1-3 and Comparative Example 1 were sampled and subjected to sensory evaluation. The test results are shown in Table 1. The sensory evaluation was conducted using the green tea evaluation method in GB / T 23776-2018 Tea Sensory Evaluation Method and the terminology in GB / T 14487-2017 Tea Sensory Evaluation Terminology. The appearance, tea soup color, aroma, flavor, and tea leaf were scored for each sample of Guzhang Maojian tea. The total sensory quality score = appearance score × 25% + aroma score × 25% + flavor score × 30% + tea soup color score × 10% + tea leaf score × 10%.

[0051] Table 1 Sensory evaluation test results

[0052]

[0053]

[0054] It can be seen from the data in Table 1 that compared with Comparative Example 1, the Maojian products prepared using Examples 1 to 3 of the present invention all showed higher total scores, and specifically showed obvious advantages in appearance, soup color, aroma, taste and leaf bottom quality.

[0055] The Maojian products prepared in Example 1 and Comparative Example 1 were sampled and tested for biochemical composition analysis. The test results are shown in Table 2. The biochemical composition analysis test method is as follows:

[0056] The water extract content was determined according to GB / T 8305-2013, "Determination of Water Extracts from Tea." The tea polyphenol content was determined according to GB / T 8313-2018, "Determination of Tea Polyphenols and Catechins in Tea." The total free amino acid content was determined according to GB / T 8314-2013, "Determination of Total Free Amino Acids in Tea." The soluble sugar content was determined using the anthrone-sulfuric acid colorimetric method. The phenol-to-amino acid ratio is the ratio of the tea polyphenol content to the free amino acid content.

[0057] Determination of catechin components (in this test, simple catechins and ester-type catechins): Mobile phase A: ultrapure water; Mobile phase B: a mixture of N,N-dimethylformamide, methanol, and glacial acetic acid (volume ratio of N,N-dimethylformamide:methanol:glacial acetic acid = 39.5:2:1.5); Chromatographic column: ECOSIL C18 (4.6 nm × 150 mm, 5 μm); Flow rate: 1.0 mL / min; Detection wavelength: 280 nm; Column temperature: 30°C; Injection volume: 10 mL; Gradient elution was used with an initial mobile phase B concentration of 9%, which was increased to 14% after 10 minutes, further increased to 36% after 27 minutes, maintained at this concentration for 4 minutes, reduced to 9% at 32 minutes, and terminated at 37 minutes.

[0058] Table 2 Biochemical component analysis test results

[0059]

[0060] As shown in Table 2, compared to Comparative Example 1, the present invention utilizes Example 1 to optimize the flavor of tea by regulating the synergistic effect of spreading and fixing the tea leaves, achieving a fresh and sweet experience. Specifically, the water extract content in the tea soup of Example 1 reached 43.13%, a 3.4% increase over Comparative Example 1. Among them, the free amino acid content and soluble sugar content increased by 0.16% and 0.12% respectively compared to Comparative Example 1, while the tea polyphenol content and phenol-ammonia ratio decreased by 0.67% and 0.4%, respectively. This "high sugar, high ammonia, low phenol" biochemical characteristic enhances the fresh and sweet taste of the tea soup. Compared to Comparative Example 1, the phenol-ammonia ratio in the tea soup of Example 1 decreased by 0.4%, and the ratio of simple catechins to ester-type catechins in the tea soup of Example 1 reached 0.319, a 4.2% increase over Comparative Example 1. This change effectively reduced the bitterness of the tea soup.

[0061] The Maojian products prepared in Example 1 and Comparative Example 1 were sampled and tested for volatile component analysis. The test results are shown in Table 3. In Table 3, "--" indicates that no volatile component was detected. The volatile component analysis test method is as follows:

[0062] Sample pretreatment: After removing the samples from the -20°C freezer, they were immediately ground under liquid nitrogen to ensure thorough pulverization and vortex mixing. Approximately 1 g of each sample was weighed into a headspace vial, and 10 mL of saturated sodium chloride solution and 10 μL of ethyl decanoate internal standard (10 mg / L) were added. The samples were further extracted using HS-SPME for GC-MS analysis. Each sample was measured three times to enhance data accuracy and reliability.

[0063] HS-SPME extraction: A 50 / 30 μm DVB / CAR / PDMS extraction tip was inserted into the sample headspace vial at 80°C for 45 minutes. The sample was then desorbed at 250°C for 5 minutes before GC-MS separation and identification. The tip was conditioned at 250°C for 5 minutes in a fiber conditioning station before sampling.

[0064] GC-MS analysis method:

[0065] Chromatographic conditions: DB-5MS capillary column (30 m × 0.25 mm, 0.25 μm, Agilent J&W Scientific, Folsom, CA, USA), high-purity helium (purity not less than 99.999%) as carrier gas, constant flow rate of 1.2 mL / min, inlet temperature of 250°C, splitless injection, and solvent delay of 3.5 min.

[0066] Mass spectrometry conditions: electron impact ion source (EI), ion source temperature 230°C, quadrupole temperature 150°C, mass spectrometry interface temperature 280°C, electron energy 70 eV, detection mode in scanning mode (SCAN), and precise scanning of qualitative and quantitative ions.

[0067] Table 3 Volatile component analysis test results

[0068]

[0069] As shown in Table 3, compared with Comparative Example 1, the present invention uses Example 1 to regulate the synergistic effect of spreading and fixing the green tea leaves, thereby achieving a floral aroma of the tea leaves. Specifically, the total content of volatile components in the tea leaves of Example 1 reached 705.14 μg / kg, an increase of 54% over that of Comparative Example 1. Among them, the content of indole, a floral aroma substance, in the tea leaves of Example 1 was 82.81 μg / kg, which was 22.7 times that of Comparative Example 1. The content of methyl salicylate, a floral aroma substance, in the tea leaves of Example 1 was 48.18 μg / kg, which was 2.8 times that of Comparative Example 1. In addition, cis-jasmone and methyl jasmonate, which have floral and jasmine aromas in the tea leaves of Example 1, were not detected in the tea leaves of Comparative Example 1. The content of chestnut-flavored volatile substances such as geraniol, nonanal, and β-ionone was prominent in the tea leaves of Comparative Example 1, but was significantly reduced in the tea leaves of Example 1.

[0070] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for preparing fresh and sweet floral Maojian tea, characterized in that: include: Step S1, selecting materials, selecting fresh tea leaves of Maojian tea with a single bud, one bud and one leaf, and / or one bud and two leaves, free of pests and diseases and mechanical damage as raw materials; Step S2, spreading the fresh tea leaves, spreading them flat, and passing normal temperature air at room temperature until no water droplets are left on the surface of the fresh tea leaves; then, subjecting the fresh tea leaves to intermittent hot air treatment to obtain tea leaves after spreading; the hot air temperature used in the hot air treatment is 35-45°C, and the treatment time is 10-15 minutes; between each two adjacent hot air treatments, the tea leaves are allowed to stand for 30-35 minutes, and the tea leaves are turned over during the standing period; Step S3, fixing, putting the tea leaves after spreading into a fixing machine for fixing, to obtain fixed leaves; the fixing temperature used in the fixing treatment is 205-225°C, and the fixing time is 3 minutes; Step S4, rolling, after the withered leaves are cooled to room temperature, rolling to obtain rolled leaves; through the rolling process, the cell breakage rate of the rolled leaves is controlled to reach 60% to 70%, and the strip forming rate is 78% to 83%; Step S5, making strips, breaking up the rolled leaves into pieces and then drying and shaping them; then spreading them to cool and rehydrate them, and then rolling them into strips to form straight tea leaves; Step S6: After post-processing, fresh and sweet floral Maojian is obtained.

2. The method for making the sweet and floral Maojian tea according to claim 1, wherein: In step S2, the surrounding environment is kept clean and ventilated during the spreading period.

3. The method for making the sweet and floral Maojian tea according to claim 1, wherein: In step S2, the hot air treatment is performed at least twice.

4. The method for making the sweet and floral Maojian tea according to claim 1, wherein: In step S3, the tea leaves put into the fixing machine have a flat thickness of 2 to 3 cm.

5. The method for making the sweet and floral Maojian tea according to claim 1, wherein: In step S3, the fixing process further includes turning the tea leaves.

6. The method for making the sweet and floral Maojian tea according to claim 1, wherein: In step S5, the drying temperature used in the drying and shaping treatment is 80° C., and the drying time is 15 minutes; the moisture content of the tea leaves after the drying and shaping treatment is 30% to 35%.

7. The method for making the sweet and floral Maojian tea according to claim 1, wherein: In step S5, the straight tea leaves have a yield rate of more than 90%.

8. The method for making the sweet and floral Maojian tea according to claim 1, characterized in that: In step S6, the post-treatment includes a primary baking treatment; the treatment temperature used in the primary baking treatment is 80°C and the treatment time is 10 minutes; the moisture content of the tea leaves after the primary baking treatment is 12% to 20%.

9. The method for making the sweet and floral Maojian tea according to claim 8, characterized in that: In step S6, the post-treatment includes a re-drying treatment after the initial baking treatment; the treatment temperature used in the initial baking treatment is 85°C and the treatment time is 60 minutes; the moisture content of the tea leaves after the initial baking treatment is 4% to 6%.

10. A sweet floral Maojian tea, characterized in that: The tea is prepared by the method for preparing the fresh and sweet floral-scented Maojian tea according to claims 1 to 9.

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