Method for retaining bioactivity of raspberry tea freeze-dried powder by using active embedding and modification technology

Abstract

The present application relates to the technical field of biological component processing, in particular to a method for retaining the bioactivity of raspberry tea freeze-dried powder by using active embedding and modification technology, wherein non-flavonoid polyphenol, flavone, polysaccharide and amino acid peptide concentrated solution are treated respectively, special components are added, and then the mixture is subjected to homogenization, ultrasonic treatment and the like, and then freeze-dried; then the freeze-dried powders are compounded according to a specific ratio, and the compounding environment and steps are controlled, so that raspberry tea freeze-dried powder meeting the quality standards is finally obtained and used in multiple fields. The present application can efficiently retain the active substances of raspberry tea, improve the extraction rate, reduce resource waste, and the prepared freeze-dried powder has low hygroscopicity and good fluidity, and is widely used in the fields of medicine, food and cosmetics, and can also promote industrial economy and improve comprehensive benefits.

Description

Technical Field

[0001] This invention relates to the field of bio-component processing technology, specifically a method for preserving the bioactivity of lyophilized tea powder using active encapsulation and modification techniques. Background Technology

[0002] As a plant used in both food and medicine, wild strawberry tea possesses extremely high nutritional, health, and medicinal value due to its rich active ingredients, showing broad application prospects in various industries. Wild strawberry tea is rich in flavonoids, polysaccharides, proteins, amino acids, and non-flavonoid polyphenols, among other active ingredients. The total flavonoid content is as high as 13-42%, earning it the reputation of "King of Flavonoids." These flavonoids include both water-soluble and fat-soluble flavonoids, possessing various biological activities such as antioxidant, anti-inflammatory, and antibacterial properties. The protein content is 11-15%, containing not only 17 common amino acids but also special amino acids such as γ-aminobutyric acid (GABA), which is an important indicator of the maturity of wild strawberry tea. However, its large molecular weight and poor solubility limit the full utilization of its functional components. The polysaccharide content is 10-13%, but most are insoluble polysaccharides, resulting in low utilization rates with current technology. The soluble sugars are the main components contributing to the sweet aftertaste of wild strawberry tea. Non-flavonoid polyphenols account for 10-20%, and although they are one of the factors contributing to the bitterness of wild strawberry tea, they also possess unique biological activities.

[0003] However, in practical processing applications, wild berry tea faces numerous challenges. Regarding the extraction of active substances, traditional water extraction methods can only extract water-soluble flavonoids, discarding a large number of other active ingredients, resulting in significant resource waste and increased production costs. Furthermore, during extraction, flavonoids, non-flavonoid polyphenols, peptides, and other substances are highly susceptible to the effects of temperature, pH, and oxygen, undergoing oxidation, structural changes, or degradation, leading to a substantial reduction or even complete loss of bioactivity. Simultaneously, the flavonoids in wild berry tea suffer from poor water solubility and low bioavailability. At room temperature, the water solubility of free flavonoids is less than 0.1 mg / mL, resulting in poor dispersibility in the product. They are also easily degraded by gastric acid, with an intestinal absorption rate of less than 10%. When combined with other ingredients, they exhibit poor stability, easily precipitating or leading to loss of activity.

[0004] The conversion and extraction of insoluble substances in mulberry tea, such as macromolecular polysaccharides and proteins, also present challenges. Polysaccharides are mostly insoluble substances like starch and cellulose; converting them into smaller molecules to increase solubility, enhance flavor, and improve bioactivity is a current research focus, but existing technologies are not very effective in this regard. Mulberry tea proteins contain various functional peptides, such as antioxidant peptides and ACE inhibitory peptides, which have potential for anti-aging and blood pressure reduction. However, traditional processes cannot accurately release these target active peptides, nor can they effectively enrich them, and the stabilization of these active peptides remains a challenge.

[0005] Furthermore, while some technologies exist for preserving bioactivity and improving bioavailability, such as green extraction technologies like ultrasound, microwave, and bioenzyme extraction, as well as methods like membrane separation purification and low-temperature drying, they still cannot fully meet the demands. Conventional freeze-drying technology, while able to retain some bioactivity, creates a porous honeycomb structure (porosity greater than 80%) that makes the product prone to moisture absorption, leading to physical deterioration, bioactivity degradation, and microbial contamination. These problems severely restrict the healthy and efficient development of the wild tea deep-processing industry, making the development of an innovative wild tea processing technology an urgent priority. Summary of the Invention

[0006] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a method for preserving the bioactivity of frost-dried tea powder using active encapsulation and modification techniques. This method efficiently preserves the active substances in frost-dried tea, improves the extraction rate, reduces resource waste, and produces a frost-dried powder with low hygroscopicity and good flowability, making it widely applicable in the pharmaceutical, food, and cosmetic fields.

[0007] (II) Technical Principles Non-flavonoid polyphenols contain multiple phenolic hydroxyl groups (-OH) and carboxyl groups (-COOH), making them highly susceptible to oxidation by oxygen and high temperatures to form quinones, and they are also sensitive to photothermal effects. To address this characteristic, a combination of chemical covalent modification and physical encapsulation was employed: the carboxyl groups of PLGA react with the phenolic hydroxyl groups of chlorogenic acid through esterification, forming a stable covalent complex that inhibits the oxidation of phenolic hydroxyl groups; simultaneously, hydroxypropyl-β-cyclodextrin was added to encapsulate the aromatic rings of the polyphenols through a hydrophobic cavity, improving water solubility; trehalose replaced water molecules during freeze-drying to protect the conformation; and L-ascorbic acid palmitate and rosmarinic acid synergistically scavenged free radicals. After high-pressure homogenization and ultrasonic treatment, a nanoscale encapsulation system was obtained. In Example 1, the non-flavonoid polyphenol content reached 38.5 mg / g, with a DPPH retention rate >90%.

[0008] Flavonoids (such as dihydromyricetin) contain pyranone rings and multiple phenolic hydroxyl groups, exhibiting extremely poor water solubility, readily self-aggregating due to hydrophobic interactions, and sensitivity to ultraviolet light. To address these characteristics, a water-in-oil microemulsion encapsulation system was designed: medium-chain triglycerides / olive oil derivatives were used as the oil phase to dissolve the fat-soluble flavonoids; polyoxyethylene castor oil / polysorbate 80 and propylene glycol / PEG-400 were used as surface / co-surfactants to form a low-interfacial-tension nanoemulsion. Au-Flavonoid NPs (electron-transfer quenched excited states) and nano-TiO2 quantum dots (UV shielding) were introduced, along with vitamin E / vitamin C palmitate for antioxidant effects. In Example 1, the flavonoid content reached 55.0 mg / g, with a Carr index of 17, dissolving in water at 37°C in just 6.5 seconds, and a moisture absorption rate of only 2.1%.

[0009] The polysaccharides in mulberry tea are mostly insoluble macromolecules (cellulose, hemicellulose), with numerous β-1,4-glycosidic bonds and hydrogen bond networks between molecules, resulting in poor solubility and low porosity. To address this characteristic, a combination of nanofiller modification, hydrophilic modification, and structural regulation was employed: nano-SiO2 was inserted between polysaccharide chains to disrupt hydrogen bonds, increasing the interchain spacing and converting some insoluble polysaccharides to amorphous form, thus improving hydration capacity; chitosan quaternary ammonium salts increased surface hydrophilicity; and konjac glucomannan (KGM) further regulated the flexibility and pore structure of the composite system, resulting in a porosity of ≤55% for the freeze-dried product. Combined with variable-frequency ultrasound (20-40 kHz) cavitation effect, the degree of polymerization was reduced, exposing more hydroxyl groups. In Example 1, the polysaccharide content was 12.5 mg / g, the final moisture content was ≤1.5%, and the moisture absorption rate at 25℃ / 75%RH was only 2.1%, far lower than the comparative example (5.0%).

[0010] Amino acid peptides contain free thiol groups (-SH), amino groups, and carboxyl groups, which are prone to oxidation and the formation of disulfide bonds, leading to loss of activity, random aggregation, and hygroscopic adhesion. To address this characteristic, a thiol-disulfide bond exchange chemical modification was employed: 0.06% of the small molecule antioxidant peptide Gly-Cys-His (GCH) was added. Its thiol groups react with the thiol groups of glutathione in the amino acid peptide to form intermolecular disulfide bonds (-SS-), creating a redox buffer pair that reversibly consumes reactive oxygen species and protects sensitive residues such as histidine. Simultaneously, freeze-drying technology (pre-freezing rate 3-7℃ / min, microwave-assisted 40-60 W) was used to control ice crystal size and prevent peptide chain damage. In Example 1, the amino acid peptide content was 9.2 mg / g, and the total bacterial count was <10 CFU / g, demonstrating excellent hygiene indicators.

[0011] (III) Technical Solution A method for preserving the bioactivity of freeze-dried berry tea powder using active encapsulation and modification technology includes the following steps: Non-flavonoid polyphenol concentrate treatment: Trehalose, hydroxypropyl-β-cyclodextrin, L-ascorbic acid palmitate, rosmarinic acid, and PLGA are added to the non-flavonoid polyphenol concentrate; PLGA forms a stable complex with the non-flavonoid polyphenols, wherein the reaction formula between PLGA and the non-flavonoid polyphenol chlorogenic acid is as follows: The above mixture was subjected to high-pressure homogenization at 80-120 MPa for 3 cycles, each lasting 3-5 min, for a total homogenization time of 10-15 min. After homogenization, it was ultrasonically treated at 20-30 kHz frequency and 150-300 W power for 15-20 min to ensure uniform dispersion of the encapsulation system. Subsequently, freeze-drying was performed: pre-freezing temperature -45--40℃, cooling rate 3-5℃ / min, pre-freezing time 1-2 h; primary drying stage from -35℃ to -10℃, vacuum degree 5-15 Pa, drying for 20-24 h; secondary drying stage temperature 20-30℃, vacuum degree ≤5 Pa, drying for 2-4 h, until the residual water content of the product is ≤3%, thus obtaining the non-flavonoid polyphenol freeze-dried powder.

[0012] Flavonoid concentrate treatment: preparation of oil phase, surfactant, co-surfactant, antioxidant, nano-titanium dioxide quantum dots and gold nanoparticles Au-Flavonoid NPs modified with flavonoid compounds; The oil phase consists of medium-chain triglycerides and / or olive oil derivatives; the surfactant is polyoxyethylene castor oil and / or polysorbate 80; the co-surfactant is propylene glycol and / or PEG-400; and the antioxidant is vitamin E and / or vitamin C palmitate.

[0013] The oil phase was heated to 50°C, and the concentrated flavonoid solution of berry tea was added and stirred until completely dissolved. While stirring, surfactant, co-surfactant, antioxidant, nano-titanium dioxide quantum dots and Au-Flavonoid NPs were added sequentially. The mixture was homogenized at 2000–10000 rpm for 10 min using a high-speed homogenizer to form a homogeneous encapsulation premix. After homogenization, freeze-drying was performed: the pre-freezing temperature was ≤-45°C and the pre-freezing time was 1–2 h; the temperature of the primary drying stage was increased from -40°C to -5°C, the vacuum degree was 10–20 Pa, and the drying time was 15–20 h; the temperature of the secondary drying stage was 20–30°C, the vacuum degree was ≤5 Pa, and the drying time was 4–8 h, until the glass transition temperature of the product was ≥65°C, thus obtaining the flavonoid freeze-dried powder.

[0014] Polysaccharide treatment: Nano-silica, chitosan quaternary ammonium salt, and konjac glucomannan are added to the polysaccharide solution; wherein the particle size of nano-silica is 10–50 nm; the degree of substitution of chitosan quaternary ammonium salt is ≥90%; and the molecular weight of konjac glucomannan is 200–800 kDa; the amount of nano-silica added is 0.5–1.0% (w / v), the amount of chitosan quaternary ammonium salt added is 0.05–0.1% (w / v), and the amount of konjac glucomannan added is 0.03–0.06% (w / v). The above mixed solution was placed in a shear emulsifier and sheared at 8000–10000 rpm for 10–15 min to form a homogeneous emulsion. After the emulsion was emulsified, it was transferred to a refrigeration unit and allowed to stand at 4–8°C for 1–2 h to allow the components to fully interact. After standing, it was freeze-dried: the pre-freezing temperature was ≤-50°C and the pre-freezing time was 3–5 h; the temperature of the primary drying stage was raised from -30°C to 0°C, the vacuum degree was 10–20 Pa, the microwave-assisted power was 60–80 W, and the drying time was 20–24 h; the secondary drying stage temperature was 40–50°C, the vacuum degree was ≤5 Pa, and the drying time was 4–6 h; after freeze-drying, the product was pulverized with a pulverizer and passed through a 100–120 mesh sieve to make the final moisture content ≤1.5% and the porosity ≤55%, which yielded the polysaccharide freeze-dried powder.

[0015] Amino acid peptide treatment: Prepare an amino acid peptide solution and a small molecule antioxidant peptide, Gly-Cys-His; wherein the purity of the small molecule antioxidant peptide Gly-Cys-His is ≥95%, and the addition amount is 0.06% (w / v) of the amino acid peptide solution volume; add Gly-Cys-His to the amino acid peptide solution, stir evenly, and let stand at 4–8℃ for 30–60 min to allow the free sulfhydryl groups of Gly-Cys-His to undergo a disulfide bond exchange reaction with glutathione or other sulfhydryl-containing peptides in the amino acid peptide. The antioxidant peptide forms a disulfide bond with the amino acid peptide, wherein the reaction formula of Gly-Cys-His with glutathione is: After the reaction, freeze-drying is performed: the pre-freezing temperature is ≤-50℃, the cooling rate is controlled at 3–7℃ / min, and the pre-freezing time is 1–3 h; the temperature of the primary drying stage is increased from -40℃ to -10℃, the vacuum degree is 10–20 Pa, the microwave-assisted power is 40–60 W, and the drying time is 15–20 h; the temperature of the secondary drying stage is 20–30℃, the vacuum degree is 3–5 Pa, and the drying time is 3–5 h; after the drying is completed, the amino acid peptide freeze-dried powder is obtained.

[0016] Compound formulation: Weigh the following lyophilized powders by mass percentage: 30%-50% flavonoid lyophilized powder, 20%-40% non-flavonoid polyphenol lyophilized powder, 15%-20% polysaccharide lyophilized powder, and 8%-15% amino acid peptide lyophilized powder; first, dry the polysaccharide lyophilized powder in an oven at 50-60℃ for 1.5-2.5 h, then cool it to room temperature in an environment with humidity ≤15%; then add the amino acid peptide lyophilized powder and flavonoid lyophilized powder to a mixing device and mix at a low speed of 100-200 rpm for 5-10 min to obtain a peptide-flavonoid premix; add the non-flavonoid polyphenol lyophilized powder to the peptide-flavonoid premix and mix at a medium speed of 300-500 rpm for 10-15 min. The mixture is stirred for 3-4 minutes to form a polyphenol-flavonoid complex. Finally, dried and cooled polysaccharide freeze-dried powder is added to the polyphenol-flavonoid complex, and magnesium stearate is sprayed in by atomization. The amount of magnesium stearate added is 0.2%-1.0% of the total material mass. The mixture is stirred at high speed at 500-800 rpm for 3-8 minutes. After stirring, the mixture is passed through a 40-80 mesh sieve to obtain berry tea freeze-dried powder.

[0017] Preferably, in the non-flavonoid polyphenol concentrate treatment step, the freeze-drying procedure is as follows: pre-freeze to -45°C, cooling rate 5°C / min, pre-freeze time 2h; primary drying stage, temperature rises from -35°C to -10°C, microwave power 60W, vacuum degree 10Pa, drying for 20-24h; secondary drying stage, temperature 25°C, vacuum degree 3Pa, drying for 3h, so that the residual water content is ≤3%.

[0018] Preferably, in the flavonoid concentrate treatment step, a microfluidic chip is used to precisely mix the mixed solution and control the particle size. The channel width of the microfluidic chip is 50-100μm. By controlling the flow rate ratio of the oil phase: surfactant: co-surfactant and other additives mixture to 3:2:1, the resulting encapsulation system has a more uniform particle size distribution and higher stability.

[0019] Preferably, in the shear emulsification process of the polysaccharide treatment step, variable frequency ultrasonic-assisted technology is used, with the ultrasonic frequency dynamically changing between 20-40kHz and the power adaptively adjusted between 100-300W, in order to further optimize the dispersion and structural modification effect of polysaccharides.

[0020] Preferably, in the amino acid peptide processing step, the freeze-drying procedure is as follows: pre-freezing temperature ≤ -50℃, cooling rate controlled at 3-7℃ / min according to solution characteristics, pre-freezing time 1-3h; primary drying stage, temperature rises from -40℃ to -10℃, vacuum degree 10-20Pa, microwave power 40-60W, drying for 15-20h; secondary drying stage, temperature 20-30℃, vacuum degree 3-5Pa, drying for 3-5h; the freeze-drying equipment is equipped with a real-time monitoring system, which can monitor the temperature, pressure, and moisture content during the freeze-drying process online, and automatically adjust the heating power and vacuum degree through the feedback control system to ensure precise control of the freeze-drying process and improve the activity retention rate of amino acid peptides.

[0021] Preferably, in the compounding step, the mixing equipment adopts a three-dimensional motion mixer with an oscillation amplitude of ±30° and a rotation speed of 30-50 r / min, which can achieve all-round uniform mixing of each component and improve the quality stability of the compounded product.

[0022] Preferably, the frost-dried tea powder product is prepared according to any one of the above methods.

[0023] Preferably, according to the application of the berry tea freeze-dried powder product described above in the pharmaceutical, food, and cosmetic fields, in the pharmaceutical field, it is used to prepare sustained-release capsules for the treatment of cardiovascular diseases, with the content of berry tea freeze-dried powder in the capsules being 300-500 mg / capsule; in the food field, it is used as a raw material for solid beverages, with an addition amount of 10-20 g / 100 g; in the cosmetic field, it is used to prepare antioxidant face creams, with an addition amount of 5-10 g / 100 g.

[0024] (iii) Beneficial technical effects Compared with existing technologies, the beneficial effects of this invention are: 1. Through unique active encapsulation and modification technology, combined with synergistic antioxidant and structural densification treatment, the bioactivity of various active substances in berry tea is greatly preserved. In the non-flavonoid polyphenol concentrate treatment, the added rosmarinic acid and L-ascorbic acid palmitate compound antioxidant system enhances the antioxidant effect. In the flavonoid concentrate treatment, the gold nanoparticles and nano-titanium dioxide quantum dots modified with flavonoid compounds significantly improve the stability of flavonoids through electron transfer and photostabilization reactions, respectively. In the polysaccharide treatment, the synergistic effect of konjac glucomannan and polysaccharides improves the structure and properties of polysaccharides. The small molecule antioxidant peptides added during the amino acid peptide treatment effectively protect the activity of amino acid peptides. After treatment, the DPPH free radical scavenging retention rate of polyphenols and flavonoids in the freeze-dried product is greater than 90%, while that of traditional processes is less than 70%, and the loss rate of key components is only 10%.

[0025] 2. The extraction rate of raw materials for mulberry tea is increased to 95%, far exceeding the 80% of traditional processes, achieving zero waste across the entire industrial chain and reducing production costs. From the perspective of driving industrial economic development, the annual output value of a single production line is expected to reach 200-300 million yuan, which can drive the development of upstream and downstream industrial chains such as planting, processing, and packaging, and create a large number of employment opportunities. At the same time, this technology can be extended to other medicinal and edible plants, contributing to rural revitalization and the development of local characteristic resources.

[0026] 3. In the pharmaceutical field, it can be directly used to prepare oral tablets and lyophilized injections; in the food field, due to its good functionality, low hygroscopicity, and good flowability, it is suitable for making solid beverages and chewable tablets; in the cosmetics field, it can retain natural antioxidant activity and is suitable for lyophilized masks, serums, and other dosage forms to meet the needs of different industries. Attached Figure Description

[0027] Figure 1 This is a flowchart of the method for preserving the bioactivity of freeze-dried berry tea powder using active encapsulation and modification technology proposed in this invention; Figure 2 This is a bar chart comparing the active ingredient content of the examples and comparative examples; Figure 3 This is a radar comparison chart of the active ingredient content of the examples and comparative examples after unifying the dimensions; Figure 4 This is a comparison chart of the flowability and hygroscopicity of the examples and comparative examples; Figure 5 This is the NMR spectrum of the product containing disulfide bonds generated by the reaction of Gly-Cys-His with glutathione. Detailed Implementation

[0028] Example 1 Treatment of non-flavonoid polyphenol concentrate: Accurately measure 1000 mL of non-flavonoid polyphenol concentrate A3, and add 80 g trehalose, 50 g hydroxypropyl-β-cyclodextrin, and 1 g... L-Ascorbyl Palmitate, 0.5g rosmarinic acid, and 0.2g polylactic-glycolic acid copolymer (PLGA) were mixed and homogenized in a high-pressure homogenizer for 15 minutes (3 cycles at 100 MPa). The homogenized solution was then transferred to an ultrasonic device and sonicated at 25 kHz and 250 W for 20 minutes. Following this, freeze-drying was performed by pouring the solution into a tray to a thickness of 2 cm. During the pre-freezing stage, the temperature was lowered to -45°C at a rate of 5°C / min and maintained for 2 hours. During the primary drying stage, the temperature was increased from -35°C to -10°C at a rate of 0.5°C / h, while simultaneously using a microwave at 60 W and maintaining a vacuum of 10 Pa for 24 hours. During the secondary drying stage, the temperature was increased to 25°C, the vacuum was adjusted to 3 Pa, and the product was dried for 3 hours until the residual water content was ≤3%. After drying, the freeze-dried product was removed and placed in a desiccator for later use. Flavonoid concentrate treatment: According to the formula, prepare 500g of oil phase (375g of medium-chain triglycerides and 125g of olive oil derivatives), 400g of surfactant (267g of food-grade polyoxyethylene castor oil and 133g of polysorbate 80), 100g of co-surfactant (33g of propylene glycol and 67g of PEG-400), 5g of vitamin, 2g of nano-titanium dioxide quantum dots, and 1g of flavonoid-modified gold nanoparticles (Au-Flavonoid NPs); heat the oil phase to 50℃, add 3300mL of berry tea flavonoid concentrate B3, and stir until completely dissolved; then add the surfactant, co-surfactant, vitamin, nano-titanium dioxide quantum dots, and Au-Flavonoid in sequence. NPs were homogenized using a high-speed homogenizer at 5000 rpm for 10 minutes to form a homogenized pre-concentrated solution. After homogenization, the solution was stirred for 30 minutes under light-protected conditions. The solution was then freeze-dried, with 5 mL of solution placed in vials. During the pre-freezing stage, the temperature was lowered to -50°C at a rate of 7°C / min and maintained for 1.5 hours. During the primary drying stage, the temperature was increased from -40°C to -5°C at a rate of 1°C / h, with a microwave power of 60W and a vacuum of 15 Pa maintained for 18 hours. During the secondary drying stage, the temperature was increased to 30°C, the vacuum was adjusted to 0.05 Pa, and the solution was dried for 10 hours, achieving a glass transition temperature (Tg) of 68°C. After drying, the vials were sealed and stored. Polysaccharide treatment: Take 1000mL of polysaccharide solution C1, add 8g of nano-silica, 0.8g of chitosan quaternary ammonium salt, and 0.5g of konjac glucomannan; pour the solution into a shear emulsifier and shear emulsify at 9000rpm for 15 minutes; after emulsification, transfer the solution to a refrigeration device and let it stand at 6℃ for 1.5h; then freeze-dry, spreading the solution evenly in a freeze-drying tray with a thickness of 1.5cm; during the pre-freezing stage, pre-freeze at -50℃ for 4h; during the primary drying stage, raise the temperature from -30℃ to 0℃ at a heating rate of 1℃ / h, maintain a vacuum of 10Pa, turn on the microwave power of 80W, and dry for 24h; during the secondary drying stage, raise the temperature to 50℃, adjust the vacuum to 5Pa, and dry for 6h; after freeze-drying, pulverize the product with a pulverizer and pass it through a 120-mesh sieve to ensure that the final moisture content is ≤1.5% and the porosity is ≤55%; Amino acid peptide treatment: Take 1000mL of amino acid peptide solution, add 0.6g of small molecule antioxidant peptide (Gly-Cys-His), and stir evenly; pour the solution into a freeze-drying container and freeze-dry; in the pre-freezing stage, according to the solution characteristics, lower the temperature to -50℃ at a cooling rate of 5℃ / min and pre-freeze for 2h; in the primary drying stage, raise the temperature from -40℃ to -10℃ at a heating rate of 1℃ / h, maintain a vacuum of 15Pa, turn on the microwave power of 50W, and dry for 18h; in the secondary drying stage, raise the temperature to 25℃, adjust the vacuum to 4Pa, and dry for 4h; Compounding: In a cleanroom with humidity ≤25% and temperature 18℃, first weigh 15g of peptide / amino acid powder and 25g of flavonoid powder, put them into a three-dimensional motion mixer, and mix at a low speed of 200rpm for 10min; then add 40g of non-flavonoid polyphenol powder, adjust the speed to 400rpm, and mix at a medium speed for 15min to form a polyphenol-flavonoid complex; weigh 20g of polysaccharide powder, dry it in an oven at 55℃ for 2.5h, and then cool it to room temperature in an environment with humidity ≤15%; add the pretreated polysaccharide powder to the above complex, and spray in 0.5g of magnesium stearate at the same time, adjust the mixer speed to 600rpm, and mix at a high speed for 5min; after mixing, pass it through a 60-mesh sieve to obtain berry tea freeze-dried powder.

[0029] The test results of the prepared lyophilized tea powder showed that its non-flavonoid polyphenol content was 38.5 mg / g, flavonoid content reached 55.0 mg / g, polysaccharide content was 12.5 mg / g, and amino acid peptide content was 9.2 mg / g. The product has excellent physical properties, with a Carr index of 17, indicating good flowability. It can completely dissolve in water at 37℃ in only 6.5 seconds. Under the conditions of 25℃ and 75% relative humidity for 24 hours, the moisture absorption rate is 2.1%, showing good stability. The microbiological indicators are excellent, with a total colony count of <10 CFU / g and no heavy metal lead (Pb) detected. These data indicate that the lyophilized powder has a high content of active ingredients and excellent physicochemical properties.

[0030] Example 2 Processing of non-flavonoid polyphenol concentrate: Accurately measure 1000 mL of non-flavonoid polyphenol concentrate, and add 80 g of trehalose, 50 g of hydroxypropyl-β-cyclodextrin, 1 g of L-ascorbic acid palmitate, 0.5 g of rosmarinic acid, 0.3 g of vitamin E, and 0.2 g of PLGA sequentially; place the mixture in a high-pressure homogenizer and cycle it 3 times at 100 MPa for a total homogenization time of 12 min; then transfer it to an ultrasonic device and sonicate it at 25 kHz frequency and 250 W power for 18 min; then freeze-dry it: pre-freeze to -45℃ at a cooling rate of 5℃ / min for 2 h; primary drying temperature is increased from -35℃ to -10℃, microwave power is 60 W, vacuum degree is 10 Pa, and drying is carried out for 22 h; secondary drying temperature is 25℃, vacuum degree is 3 Pa, and drying is carried out for 3 h, so that the residual water content is ≤3%, and non-flavonoid polyphenol freeze-dried powder is obtained.

[0031] Flavonoid concentrate treatment: Weigh the oil phase (380 g medium-chain triglycerides, 120 g olive oil derivatives), surfactants (270 g polyoxyethylene castor oil, 130 g polysorbate 80), co-surfactants (35 g propylene glycol, 65 g PEG-400), antioxidants (5 g vitamin E, 1 g vitamin C palmitate), 2 g nano-titanium dioxide quantum dots, and 1.2 g Au-Flavonoid NPs; heat the oil phase to 50℃, add 300 mL of berry tea flavonoid concentrate, and stir to dissolve; add the surfactants, co-surfactants, antioxidants, nano-titanium dioxide quantum dots, and Au-Flavonoid NPs sequentially, and homogenize at 5000 rpm for 10 min using a high-speed homogenizer; then freeze-dry: pre-freeze to -48℃ and hold for 1.5 h; primary drying temperature is increased from -40℃ to -5℃, vacuum degree 15 Pa, microwave power 60 W, and drying for 18 hours. The secondary drying temperature was 25℃, the vacuum degree was 0.1 Pa, and drying lasted for 6 h until the glass transition temperature of the product reached ≥65℃, yielding flavonoid lyophilized powder. Analysis showed that the initial flavonoid content of the raw material was 120 mg / g (based on the concentrate before lyophilization), and the flavonoid content in the prepared lyophilized powder was 55.2 mg / g, with a calculated flavonoid retention rate of 92.0%. Polysaccharide treatment: Take 1000 mL of polysaccharide solution, add 0.8 g of nano-silica, 0.8 g of chitosan quaternary ammonium salt, and 0.5 g of konjac glucomannan; emulsify by shearing at 9000 rpm for 12 min, then let stand at 6℃ for 1.5 h; freeze drying: pre-freeze to -50℃ and keep warm for 4 h; primary drying temperature is increased from -30℃ to 0℃, vacuum degree 10 Pa, microwave power 70 W, and drying for 22 h; secondary drying temperature is 45℃, vacuum degree 5 Pa, and drying for 5 h; pulverize through a 120 mesh sieve to obtain polysaccharide freeze-dried powder with a final moisture content of 1.3% and a porosity of 52%.

[0032] Amino acid peptide treatment: Take 1000 mL of amino acid peptide solution, add 0.06% (w / v) of Gly-Cys-His 0.6 g, stir evenly, and let stand at 6℃ for 45 min; freeze-drying: pre-freeze to -50℃, cooling rate 5℃ / min, and hold for 2 h; primary drying temperature is increased from -40℃ to -10℃, vacuum degree 15 Pa, microwave power 50 W, and drying for 18 h; secondary drying temperature is 25℃, vacuum degree 4 Pa, and drying for 4 h to obtain amino acid peptide freeze-dried powder. The initial amino acid peptide content of the raw material was 18.5 mg / g, and the content after freeze-drying was 9.1 mg / g, with an activity retention rate of 98.4%.

[0033] Compound preparation: Weigh out 40% flavonoid freeze-dried powder, 30% non-flavonoid polyphenol freeze-dried powder, 18% polysaccharide freeze-dried powder, and 12% amino acid peptide freeze-dried powder by mass percentage; first, dry the polysaccharide powder in an oven at 55℃ for 2 h, and cool it to room temperature (humidity ≤15%); then mix the amino acid peptide powder and flavonoid powder (200 rpm, 8 min), and then add the non-flavonoid polyphenol powder (400 rpm, 12 min); finally, add the polysaccharide powder, and simultaneously spray in 0.5% magnesium stearate by total mass, mix at high speed of 600 rpm for 5 min, and pass through a 60-mesh sieve to obtain berry tea freeze-dried powder.

[0034] Product testing results: Non-flavonoid polyphenol content 38.3 mg / g, flavonoid content 55.2 mg / g, polysaccharide content 12.4 mg / g, amino acid peptide content 9.1 mg / g; Carr index 17, good flowability; dissolution time in water at 37℃ 6.7 seconds; moisture absorption rate at 25℃ / 75%RH for 24 hours 2.2%; total bacterial count <10 CFU / g, lead not detected. DPPH free radical scavenging retention rate: flavonoids 92.0%, polyphenols 91.5%.

[0035] Example 3 Processing of non-flavonoid polyphenol concentrate: Accurately measure 1000 mL of non-flavonoid polyphenol concentrate, and add 80 g of trehalose, 50 g of hydroxypropyl-β-cyclodextrin, 1 g of L-ascorbic acid palmitate, 0.5 g of rosmarinic acid, 0.3 g of vitamin E, and 0.2 g of PLGA sequentially; place the mixture in a high-pressure homogenizer and cycle it three times at 100 MPa for 4 min each time, for a total homogenization time of 12 min; then transfer it to an ultrasonic device and sonicate it at 20 kHz frequency and 200 W power for 18 min; then freeze-dry it: pre-freeze to -45℃ at a cooling rate of 5℃ / min for 2 h; primary drying temperature is increased from -35℃ to -10℃, microwave power is 60 W, vacuum degree is 10 Pa, and drying is carried out for 22 h; secondary drying temperature is 25℃, vacuum degree is 3 Pa, and drying is carried out for 3 h, so that the residual water content is ≤3%, and non-flavonoid polyphenol freeze-dried powder is obtained.

[0036] Flavonoid concentrate treatment: Weigh 413 g of medium-chain triglycerides and 137 g of olive oil derivatives (total 550 g); Surfactants: 267 g of polyoxyethylene castor oil and 133 g of polysorbate 80 (total 400 g); Co-surfactants: 17 g of propylene glycol and 33 g of PEG-400 (total 50 g); Antioxidants: 8 g of vitamin E and 2 g of vitamin C palmitate (total 10 g); 2.5 g of nano-titanium dioxide quantum dots; 1.2 g of Au-Flavonoid NPs. The oil phase was heated to 50℃, and 300 mL of concentrated flavonoids from berry tea was added and stirred until completely dissolved. While stirring, surfactants, co-surfactants, antioxidants, nano-titanium dioxide quantum dots, and Au-Flavonoid NPs were added sequentially. The mixture was homogenized at 5000 rpm for 10 min using a high-speed homogenizer to form a homogeneous embedded premix. Subsequently, freeze-drying was performed: pre-freezing to -48℃ and holding for 1.5 h; primary drying temperature was increased from -40℃ to -5℃, vacuum degree 15 Pa, microwave power 60 W, and drying for 18 h; secondary drying temperature was 25℃, vacuum degree 0.1 Pa, and drying for 6 h until the product's glass transition temperature ≥65℃, yielding flavonoid freeze-dried powder. Analysis showed that the initial flavonoid content of the raw material was 121 mg / g (based on the concentrate before freeze-drying), and the flavonoid content in the prepared freeze-dried powder was 55.5 mg / g, with a calculated flavonoid retention rate of 92.6%.

[0037] Polysaccharide treatment: Take 1000 mL of polysaccharide solution, add 1.0 g of nano-silica, 0.9 g of chitosan quaternary ammonium salt, and 0.6 g of konjac glucomannan; shear emulsify at 10000 rpm for 10 min, then let stand at 8℃ for 2 h; freeze drying: pre-freeze to -50℃ and keep warm for 4 h; primary drying temperature is increased from -30℃ to 0℃, vacuum degree 10 Pa, microwave power 80 W, and drying for 22 h; secondary drying temperature is 45℃, vacuum degree 5 Pa, and drying for 5 h; pulverize through a 120 mesh sieve to obtain polysaccharide freeze-dried powder with a final moisture content of 1.2% and a porosity of 50%.

[0038] Amino acid peptide treatment: Take 1000 mL of amino acid peptide solution, add 0.06% (w / v) of Gly-Cys-His 0.6 g, stir evenly, and let stand at 6℃ for 45 min; freeze-drying: pre-freeze to -50℃, cooling rate 6℃ / min, hold for 2 h; primary drying temperature from -40℃ to -10℃, vacuum degree 20 Pa, microwave power 40 W, dry for 18 h; secondary drying temperature 25℃, vacuum degree 4 Pa, dry for 4 h, to obtain amino acid peptide freeze-dried powder. The initial amino acid peptide content of the raw material was 18.8 mg / g, and the content after freeze-drying was 9.4 mg / g, with an activity retention rate of 98.9%.

[0039] Compound formulation: Weigh out 45% flavonoid lyophilized powder, 35% non-flavonoid polyphenol lyophilized powder, 16% polysaccharide lyophilized powder, and 14% amino acid peptide lyophilized powder by mass percentage. First, dry the polysaccharide powder in an oven at 55℃ for 2 hours, then remove it and cool it to room temperature in an environment with humidity ≤15%. Then, add the amino acid peptide lyophilized powder and flavonoid lyophilized powder to a three-dimensional motion mixer and mix at a low speed of 200 rpm for 8 minutes. Next, add the non-flavonoid polyphenol lyophilized powder and mix at a medium speed of 400 rpm for 12 minutes. Finally, add the dried and cooled polysaccharide lyophilized powder, and simultaneously spray in 0.5% of the total material mass of magnesium stearate in a mist manner, and mix at a high speed of 600 rpm for 5 minutes. After mixing, pass the mixture through a 60-mesh sieve to obtain berry tea lyophilized powder.

[0040] Product testing results: Non-flavonoid polyphenol content 38.8 mg / g, flavonoid content 55.5 mg / g, polysaccharide content 12.7 mg / g, amino acid peptide content 9.4 mg / g; Carr index 16, excellent flowability; dissolution time in water at 37℃ 6.2 seconds; moisture absorption rate at 25℃ / 75%RH for 24 hours 2.0%; total bacterial count <10 CFU / g, no detectable lead (Pb). DPPH free radical scavenging retention rate: flavonoids 92.6%, polyphenols 92.0%.

[0041] Comparative Example Non-flavonoid polyphenol concentrate treatment: only 8% trehalose, 5% hydroxypropyl-β-cyclodextrin, 0.1% L-ascorbic acid palmitate, and 0.05% rosmarinic acid were added, without adding polylactic acid-glycolic acid copolymer (PLGA); high-pressure homogenization was performed twice at 80 MPa for 10 min, without ultrasonic treatment; freeze drying was carried out using a conventional freeze drying procedure: pre-freezing temperature -30℃, pre-freezing time 1 h; primary drying temperature -20℃, vacuum degree 20 Pa, drying for 15 h; secondary drying temperature 30℃, vacuum degree 5 Pa, drying for 3 h.

[0042] Flavonoid concentrate treatment: Traditional encapsulation method was used, with only polysorbate 80 as a single surfactant for encapsulation, without the addition of nano-titanium dioxide quantum dots and gold nanoparticles modified with flavonoid compounds (Au-Flavonoid NPs); freeze-drying was carried out using a conventional freeze-drying procedure: pre-freezing temperature -40℃, pre-freezing time 1.5 h; primary drying temperature -30℃, vacuum degree 25 Pa, drying for 18 h; secondary drying temperature 35℃, vacuum degree 8 Pa, drying for 5 h.

[0043] Polysaccharide treatment: Only 0.5% nano silica was added, without adding chitosan quaternary ammonium salt or konjac glucomannan; shear emulsification speed was 6000 rpm, emulsification time was 8 min, and no standing treatment was performed; freeze drying adopted conventional freeze drying procedure: pre-freezing temperature -45℃, pre-freezing time 3 h; primary drying temperature -25℃, vacuum degree 15 Pa, drying time 20 h; secondary drying temperature 40℃, vacuum degree 6 Pa, drying time 5 h.

[0044] Amino acid peptide treatment: No small molecule antioxidant peptides (Gly-Cys-His) were added; freeze drying was carried out using a conventional freeze drying procedure: pre-freezing temperature -40℃, pre-freezing time 2 h; primary drying temperature -30℃, vacuum degree 20 Pa, drying time 18 h; secondary drying temperature 30℃, vacuum degree 5 Pa, drying time 4 h.

[0045] Compounding: Compounding is carried out under normal conditions (humidity 40%, temperature 25℃). The compounding ratio is set arbitrarily as follows: 20% flavonoid freeze-dried powder, 30% non-flavonoid polyphenol freeze-dried powder, 25% polysaccharide freeze-dried powder, and 25% amino acid peptide freeze-dried powder. Simple stirring is used during mixing. A three-dimensional motion mixer is not used, and magnesium stearate is not sprayed in or sieved.

[0046] Test results showed that the freeze-dried berry tea powder contained 35.0 mg / g of non-flavonoid polyphenols, 45.0 mg / g of flavonoids, 10.0 mg / g of polysaccharides, and 8.0 mg / g of amino acid peptides. Regarding physical properties, the Carr index was 25, indicating moderate flowability. The dissolution time in water at 37℃ was 12.0 seconds, indicating room for improvement in solubility. The moisture absorption rate after 24 hours at 25℃ and 75% relative humidity was 5.0%, suggesting further improvement in moisture resistance. In terms of hygiene indicators, the total bacterial count was 50 CFU / g. Although lead (Pb) was not detected, some other hygiene indicators exceeded the standard limits.

[0047] Comparison table of active ingredient content between examples and comparative examples:

[0048] Conclusion: This table shows the content of active ingredients in the freeze-dried tea powder of the examples and comparative examples. The contents of non-flavonoid polyphenols, flavonoids, polysaccharides, and amino acid peptides in the examples are all higher than those in the comparative examples, indicating that the preparation method of the present invention can more effectively retain and enrich the active ingredients in tea.

[0049] Performance comparison table of the examples and comparative examples:

[0050] Conclusion: This table compares the flowability, dissolution time, hygroscopicity, and total bacterial count of the products from Examples 1-3 and the comparative example. The Carr index of each example was lower than that of the comparative example (16-17 vs 25), indicating that the lyophilized tea powder prepared by this invention has superior flowability; the dissolution time (6.2-6.7 seconds) is significantly shorter than that of the comparative example (12.0 seconds), indicating good rapid solubility; the hygroscopicity (2.0-2.2%) is much lower than that of the comparative example (5.0%), indicating excellent moisture resistance; and the total bacterial count (<10 CFU / g) is much lower than that of the comparative example (50 CFU / g), indicating a significant improvement in hygiene quality. The above data demonstrate that the lyophilized tea powder prepared by the method of this invention has significant advantages in both product performance and hygiene quality.

[0051] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preserving the bioactivity of freeze-dried tea berry powder using active encapsulation and modification technology, characterized in that, Includes the following steps: Non-flavonoid polyphenol concentrate treatment: Trehalose, hydroxypropyl-β-cyclodextrin, L-ascorbate palmitate, antioxidants, and PLGA were added to the non-flavonoid polyphenol concentrate; PLGA forms a stable complex with the non-flavonoid polyphenols, wherein the reaction formula between PLGA and the non-flavonoid polyphenol chlorogenic acid is as follows: The mixture was subjected to high-pressure homogenization for three cycles, each lasting 10-15 minutes, followed by ultrasonic treatment for 15-20 minutes; then freeze-dried. Flavonoid concentrate treatment: Prepare an oil phase, surfactant, co-surfactant, antioxidant, nano-titanium dioxide quantum dots, and gold nanoparticles modified with flavonoid compounds (Au-Flavonoid NPs); heat the oil phase to 50°C and add the flavonoid concentrate from the tea berry, stir to dissolve, and then add the surfactant, co-surfactant, antioxidant, nano-titanium dioxide quantum dots, and Au-Flavonoid NPs in sequence. Homogenize for 10 min and finally freeze dry. Polysaccharide treatment: Nano-silica, chitosan quaternary ammonium salt, and konjac glucomannan are added to the polysaccharide solution; emulsification is carried out by shearing, followed by standing and then freeze-drying; after freeze-drying, the mixture is pulverized and sieved to achieve a final moisture content ≤1.5% and porosity ≤55%. Amino acid peptide treatment: The amino acid peptide solution was freeze-dried. Before freeze-drying, 0.06% of the small molecule antioxidant peptide Gly-Cys-His was added to the amino acid peptide solution. This antioxidant peptide forms disulfide bonds with the amino acid peptide. The reaction formula between Gly-Cys-His and glutathione is as follows: Compound: 30%-50% flavonoid freeze-dried powder, 20%-40% non-flavonoid polyphenol freeze-dried powder, 15%-20% polysaccharide freeze-dried powder, and 8%-15% amino acid peptide freeze-dried powder; First, dry and cool the polysaccharide powder in an oven; then mix the peptide / amino acid powder with the flavonoid powder, and then add the non-flavonoid polyphenol powder; finally, add the polysaccharide powder and mix at high speed, while simultaneously spraying in magnesium stearate, and then sieve to obtain berry tea freeze-dried powder.

2. The method for preserving the bioactivity of lyophilized tea powder using active encapsulation and modification technology according to claim 1, characterized in that: In the non-flavonoid polyphenol concentrate processing step, the freeze-drying procedure is as follows: pre-freeze to -45℃, cooling rate 5℃ / min, pre-freeze time 2h; primary drying stage, temperature rises from -35℃ to -10℃, microwave power 60W, vacuum degree 10Pa, drying for 20-24h. In the secondary drying stage, the temperature is 25℃, the vacuum degree is 3Pa, and the drying time is 3h, so that the residual water content is ≤3%.

3. The method for preserving the bioactivity of freeze-dried berry tea powder using active encapsulation and modification technology according to claim 1, characterized in that, In the flavonoid concentrate processing step, a microfluidic chip is used to precisely mix the mixed solution and control the particle size. The channel width of the microfluidic chip is 50-100μm. The flow rate ratio of the oil phase: surfactant: co-surfactant and other additives in the mixture is controlled to be 3:2:

1.

4. The method for preserving the bioactivity of freeze-dried berry tea powder using active encapsulation and modification technology according to claim 1, characterized in that, In the amino acid peptide processing step, the freeze-drying procedure is as follows: the pre-freezing temperature is ≤-50℃, the cooling rate is controlled at 3-7℃ / min according to the solution characteristics, and the pre-freezing time is 1-3h; in the primary drying stage, the temperature is raised from -40℃ to -10℃, the vacuum degree is 10-20Pa, the microwave power is 40-60W, and the drying time is 15-20h. In the secondary drying stage, the temperature is 20-30℃, the vacuum degree is 3-5Pa, and the drying time is 3-5h.

5. The method for preserving the bioactivity of lyophilized tea powder using active encapsulation and modification technology according to claim 1, characterized in that, In the compounding step, a three-dimensional motion mixer was used as the mixing equipment. The mixer's oscillation range was ±30°, and its rotation speed was 30-50 r / min.

6. The method for preserving the bioactivity of lyophilized tea powder using active encapsulation and modification technology according to claim 1, characterized in that, The antioxidant is rosmarinic acid.

7. A freeze-dried berry tea powder product prepared by the method according to any one of claims 1-6.

8. The application of the freeze-dried berry tea powder product according to claim 7 in the fields of medicine, food, and cosmetics.

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