Preparation method of Pu'er ripe tea with pseudo-ginseng leaf and stem extract

Abstract

The invention relates to the field of preparation of Pu'er tea, in particular to a preparation method of Pu'er ripe tea with a pseudo-ginseng leaf and stem extract. The preparation method of the Pu'er ripe tea with the panax notoginseng leaf and stem extract has the following advantages: (1) optimized cellulase treatment (the dosage is 0.5% of the mass of panax notoginseng leaf powder) and ethanol extraction conditions (70% of an ethanol solution, and the pH value is adjusted to 5.0) are adopted, so that the extraction efficiency and purity of active ingredients of panax notoginseng leaves and stems are remarkably improved (the content of total saponins in dry powder of the total panax notoginseng extract is ensured to be greater than or equal to 12%); and impurity residues are reduced. (2) the pile fermentation process is controlled in stages (1-5 days at the initial stage and 6-15 days at the middle stage), so that the Pu'er tea is uniformly cured, and the tea soup mellowness and flavor stability are enhanced. And (3) eluting and drying by using D101 macroporous resin to improve the yield of the extract, screening to remove tea stems, and packaging by using aluminum foil bags to maintain the freshness and long-term storage property of the product.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of pu'er tea preparation, in particular to a method for preparing a pu'er ripe tea containing ginseng leaf and stem extract. BACKGROUND

[0002] As a traditional fermented tea in China, pu'er tea is endowed with a mellow and smooth taste and a quality of aged aroma by its unique pile fermentation process. In recent years, in order to enrich the functional value of pu'er tea, the research on the integration of medicinal plant extract and pu'er tea has gradually increased. Ginseng, as a precious Chinese herbal medicine, has significant effects in cardiovascular health, anti-inflammatory and antioxidant, etc. due to its main active ingredients (such as saponins, flavonoids, etc.).

[0003] In the prior art, although there are attempts to add plant extracts to tea leaves, there are generally the following problems: first, the extraction method is rough, and the effective components are easy to decompose and inactivate in the high-temperature and high-humidity environment during fermentation; second, there is a lack of integration technology matching the pile fermentation process of pu'er tea, resulting in poor combination of the extract and the tea matrix and poor flavor coordination of the finished tea; third, the fermentation process parameters (such as temperature, humidity, and turning period) are not optimized for the composite system, making it difficult to stably achieve efficient preservation of functional components and flavor synergy. SUMMARY

[0004] The present application aims to provide a method for preparing a pu'er ripe tea containing ginseng leaf and stem extract, and the specific scheme is as follows: A method for preparing a pu'er ripe tea containing ginseng leaf and stem extract, comprising the following steps: (1) Ginseng leaf extraction: S1. Enzymatic pretreatment: add ginseng leaf powder into an enzymatic tank, add ethanol solution, and stir uniformly; add cellulase, start stirring, and water bath for heat preservation to obtain an enzymatic solution; S2. Ultrasonic-assisted extraction: transfer the enzymatic solution into an ultrasonic extraction instrument, filter the hot extract with three layers of gauze, wash the residue with ethanol at room temperature, and combine the filtrates; S3. Reducing pressure concentration: transfer the filtrate into a rotary evaporator, concentrate, and obtain ginseng leaf extract; (2) Ginseng stem extraction; (3) Purification process: obtain ginseng total extract dry powder; (4) Fermentation integration with pu'er tea: S1. Raw material ratio and mixing Mix the ginseng total extract dry powder and purified water to obtain a mixture, and uniformly spray the mixture on the green tea, and manually knead until the tea base completely absorbs the liquid; S2. Pile fermentation control Initial stage: the pile height is 70-100 cm, the temperature is controlled at 55-60℃, and the pile is turned over once every 20-26 hours; middle stage: the temperature is maintained at 50-55℃, and the pile is turned over once every 46-52 hours; • S3. Firing and drying After fermentation, the tea dregs are immediately spread and cooled to room temperature by using a continuous steam firing machine; hot air drying is performed until the moisture content is 10-12%; • S4. Screening and packaging After drying, the tea sample is screened to remove tea stems, and is then packed into aluminum foil bags to obtain the Gynura japonica Pu'er ripe tea loose tea.

[0005] The amount of cellulase used in the S1 step of step (1) is 0.5% of the mass of the Gynura japonica leaf powder.

[0006] The ethanol used in the S1 step of step (1) is a 70% ethanol solution, and the pH is adjusted to 5.0 in advance with citric acid.

[0007] The solid-liquid ratio of the Gynura japonica leaf powder and the ethanol solution is 1:10-30.

[0008] The mass fraction of the mixture of the Gynura japonica total extract dry powder in the S1 step of step (4) is 13-15%.

[0009] The Gynura japonica total extract dry powder accounts for 2-3% of the mass of the raw tea in the S1 step of step (4).

[0010] The initial stage in the S2 step of step (4) is maintained for 1-5 days, and the middle stage is maintained for 6-15 days.

[0011] The step (3) comprises the following steps: resin column pretreatment, sample loading and elution, and drying into powder, and the resin column is a D101 macroporous resin.

[0012] The Gynura japonica leaf is a dry three-year-old Gynura japonica leaf, and the moisture content is ≤8%, and the total ginsenoside content is ≥2.5%.

[0013] The Gynura japonica stem is a two-year-old stem segment, and the diameter is that of a two-year-old stem segment.

[0014] The method for preparing the Gynura japonica leaf and stem extract Pu'er ripe tea has the following advantages: (1) The optimized cellulase treatment (the amount is 0.5% of the mass of the Gynura japonica leaf powder) and the ethanol extraction conditions (70% ethanol solution, pH adjusted to 5.0) significantly improve the extraction efficiency and purity of the active ingredients of the Gynura japonica leaf and stem (ensure that the total ginsenoside content of the Gynura japonica total extract dry powder is ≥12%), and reduce impurity residues.

[0015] (2) Control the fermentation process in stages (initial 1-5 days, mid-term 6-15 days) to ensure uniform maturation of the Pu'er tea and enhance the thickness and flavor stability of the tea soup.

[0016] (3) Elution and drying are performed using D101 macroporous resin to improve the yield of the extract, and the product is packaged in aluminum foil bags after screening to remove tea stems, thereby maintaining the freshness and long-term storage properties of the product. DETAILED DESCRIPTION

[0017] I. Raw materials Radix Notoginseng Leaves: Dried three-year-old Radix Notoginseng leaves, ground to 60 mesh (particle size ≤ 250 μm), moisture content ≤ 8%, total saponins ≥ 2.5%. Radix Notoginseng Stems: Two-year-old stem segments (diameter 0.4-0.6 cm). Pu'er tea: Yunnan large-leaf sun-cured green tea. Reagents: food-grade ethanol (95%), cellulase (enzyme activity ≥ 5000 U / g), D101 macroporous resin (pre-treated and ready for use).

[0018] Preparation method Radix Notoginseng Leaf Extraction • S1. Enzymatic pretreatment Weigh 1 kg of Radix Notoginseng leaf powder and add it to an enzymatic hydrolysis tank. Add 70% ethanol (pre-adjusted to pH 5.0 with citric acid) at a solid-to-liquid ratio of 1:20 and stir until uniform. Add 5 g of cellulase (0.5% usage) and start stirring (speed 80 r / min). Maintain the water bath at 50°C for 2 hours.

[0019] • S2. Ultrasonic-assisted extraction Transfer the enzymatic hydrolysis solution to an ultrasonic extraction instrument and set the temperature to 60°C, the power to 300 W, and the ultrasonic time to 40 minutes (intermittent mode: work for 5 seconds and stop for 5 seconds to avoid local overheating). After extraction, filter the hot solution with three layers of gauze. Wash the residue with 70% ethanol at room temperature for 2 times and combine the filtrates.

[0020] • S3. Vacuum concentration Transfer the filtrate to a rotary evaporator (vacuum degree -0.08 MPa, water bath temperature 60°C) and concentrate it to a relative density of 1.20±0.02. The initial leaf extract is obtained.

[0021] 2. Radix Notoginseng Stem Extraction • S1. Steam explosion treatment Take 5 kg of Radix Notoginseng stem segments and load them into a steam explosion tank. Introduce 1.2 MPa saturated steam, maintain the pressure for 30 seconds, and then instantaneously release the pressure. Collect the exploded stem segments.

[0022] • S2. Composite enzymatic hydrolysis and extraction The stem section was crushed to 40 mesh, 1 kg of dry powder was weighed into the extraction tank, 50% ethanol was added according to the solid-liquid ratio of 1:15, and the pH was adjusted to 4.5. 10 g of xylanase (1%) and 5 g of pectinase (0.5%) were added, and stirred in a 45°C water bath for 3 hours. Centrifugation (4000 r / min, 15 minutes) was performed to obtain the supernatant, and the residue was washed with 50% ethanol, and the filtrates were combined.

[0023] • S3. Concentration and combination The stem extract was concentrated to a relative density of 1.15, and combined with the leaf extract to obtain a mixed extract.

[0024] 3. Purification process (6 hours / batch) • S1. Resin column pretreatment D101 macroporous resin was soaked with 95% ethanol for 24 hours, then washed with 5BV of ethanol and 5BV of deionized water until there was no alcohol smell, and was ready for use.

[0025] • S2. Sample loading and elution The mixed extract was diluted with deionized water to a solid content of 10%, and was loaded at a flow rate of 2BV / h (loading amount ≤80% of the total adsorption capacity of the resin column). After loading, the column was washed with 3BV of deionized water at a flow rate of 3BV / h (to remove water-soluble impurities), and then eluted with 70% ethanol at a flow rate of 2BV / h for 5BV, and the eluate was collected (the first 0.5BV of eluate was discarded).

[0026] • S3. Drying to powder The eluate was concentrated under reduced pressure until there was no alcohol smell, and was vacuum freeze-dried (-40°C pre-freezing for 3 hours, vacuum degree ≤10Pa, desorption temperature 40°C, drying for 12 hours) to obtain dry powder of total notoginseng extract (saponins ≥12%, polysaccharides ≥6%).

[0027] 4. Fermentation with Pu'er tea • S1. Raw material ratio and mixing 10 kg of sun-dried green tea, 250 g of dry powder of total notoginseng extract (2.5% addition), and purified water were weighed. The extract powder was dissolved in purified water to form a paste (concentration 13.9%), and was evenly sprayed on the green tea, and was hand kneaded for 20 minutes until the tea base was completely absorbed (feeling sticky and moist without dripping water).

[0028] • S2. Control of steaming and fermentation Initial stage (1-5 days): the height of the tea pile was 80 cm, the temperature was controlled at 55-60°C, and the pile was turned over every 24 hours (the temperature dropped to below 50°C after turning over). Middle stage (6-15 days): the temperature was maintained at 50-55°C, the pile was turned over every 48 hours, and the tea polyphenol content was monitored (fermentation was terminated when the retention rate was ≥60%).

[0029] • S3. Enzyme treatment After fermentation, the tea base is immediately spread to room temperature (thickness ≤ 5 cm) using a continuous steam fixation machine (100°C, 30 seconds).

[0030] • S4. Screening and packaging After drying, the tea sample is screened through a 4-mesh sieve to remove tea stems, and is then packaged into aluminum foil bags (300g per bag), vacuum packaged (vacuum degree -0.09 MPa), to obtain Sanqi Pu'er ripe tea loose tea.

[0031] The above is only a preferred embodiment of the present application, and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art will appreciate that modifications can be made to the technical solutions described in the foregoing embodiments, or some of the technical features can be replaced by equivalent features, without departing from the spirit and principles of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for making a Pu'er ripe tea from an extract of Panax notoginseng stem, characterized in that, Comprising the following steps: (1) Panax notoginseng leaf extraction: • S1. Enzymatic pretreatment: Panax notoginseng leaf powder is added to an enzymatic tank, and an ethanol solution is added and stirred uniformly; cellulase is added, stirring is started, and water bath is heated to obtain an enzymatic solution; • S2. Ultrasonic-assisted extraction: The enzymatic solution is transferred to an ultrasonic extractor, and after extraction, it is filtered while hot with three layers of gauze, and the residue is washed with ethanol at room temperature, and the filtrates are combined; • S3. Vacuum concentration: The filtrate is transferred to a rotary evaporator and concentrated to obtain the leaf extract crude product; (2) Panax notoginseng stem extraction; (3) Purification process: Panax notoginseng total extract dry powder is obtained; (4) Fermentation integration with Pu'er tea: • S1. Raw material ratio and mixing Panax notoginseng total extract dry powder and purified water are mixed to obtain a mixture, which is uniformly sprayed on the raw tea, and hand kneading is performed until the tea base completely absorbs the liquid; • S2. Fermentation control Initial stage: the tea pile height is 70-100 cm, the temperature is controlled at 55-60℃, and the pile is turned over once every 20-26 hours; mid-stage: the temperature is maintained at 50-55℃, and the pile is turned over once every 46-52 hours; • S3. Killing and drying After fermentation, the tea base is immediately spread and cooled to room temperature with a continuous steam killing machine; hot air drying is performed until the moisture content is 10-12%; • S4. Screening and packaging After drying, the tea sample is screened to remove tea stems, and is packaged into aluminum foil bags to obtain Panax notoginseng Pu'er ripe tea loose tea.

2. The method for producing Pu-erh ripe tea from Panax notoginseng leaf and stem extract as described in claim 1, characterized in that: The amount of cellulase used in step S1 of step (1) is 0.5% of the mass of Panax notoginseng leaf powder.

3. The method for producing Pu-erh ripe tea from Panax notoginseng leaf and stem extract as described in claim 1, characterized in that: The ethanol in step S1 of step (1) is a 70% ethanol solution, and the pH is adjusted to 5.0 in advance with citric acid.

4. The method for producing Pu-erh ripe tea from Panax notoginseng leaf and stem extract as described in claim 3, characterized in that: The solid-liquid ratio of Panax notoginseng leaf powder and ethanol solution is 1:10-30.

5. The method for producing Pu-erh ripe tea from Panax notoginseng leaf and stem extract as described in claim 1, characterized in that: The mass fraction of the mixture Panax notoginseng total extract dry powder in step S1 of step (4) is 13-15%.

6. The method for producing Pu-erh ripe tea from Panax notoginseng leaf and stem extract as described in claim 1, characterized in that: The amount of Panax notoginseng total extract dry powder in step S1 of step (4) is 2-3% of the mass of raw tea.

7. The method for producing Pu-erh ripe tea from Panax notoginseng leaf and stem extract as described in claim 1, characterized in that: The initial stage in step S2 of step (4) is maintained for 1-5 days, and the mid-stage is maintained for 6-15 days.

8. The method for producing Pu-erh ripe tea from Panax notoginseng leaf and stem extract as described in claim 1, characterized in that, Step (3) comprises the following steps: resin column pretreatment, sample loading and elution, and drying into powder, and the resin column is a D101 macroporous resin.

9. The method for producing Pu-erh ripe tea from Panax notoginseng leaf and stem extract as described in claim 1, characterized in that: The Panax notoginseng leaf is dried for three years, with a water content of ≤8% and a total saponin content of ≥2.5%.

10. The method for producing Pu-erh ripe tea from Panax notoginseng leaf and stem extract as described in claim 1, characterized in that: The Panax notoginseng stem is a two-year-old stem section, with a diameter of two-year-old stem section.