Extraction method of freeze-dried fresh rose flower stock solution

Abstract

The invention relates to the technical field of plant effective component extraction, in particular to an extraction method of a freeze-dried fresh rose stock solution, which comprises the following steps: selecting fresh fresh rose without plant diseases and insect pests, removing calyx, pedicel and other impurities, carrying out ultrasonic cleaning for 2-3 times by using a deionized water mixed solution containing citric acid, vitamin C and EDTA-2Na, and carrying out freeze-drying to obtain the freeze-dried fresh rose stock solution. After draining, the water content is controlled to be 86-88% through near infrared spectrum monitoring; wherein the content of citric acid in the deionized water mixed solution is 0.1%-0.3%, the content of vitamin C is 0.05%-0.08%, the content of EDTA-2Na is 0.02%-0.04%, the citric acid inhibits the activity of polyphenol oxidase, the vitamin C blocks an oxidation chain reaction, the EDTA-2Na chelates metal ions and avoids catalytic oxidation of the metal ions, and the oxidation rate of the active ingredients is reduced to 5% or below through synergism of the citric acid, the vitamin C and the EDTA-2Na.

Description

Technical Field

[0001] This invention relates to the field of plant active ingredient extraction technology, and in particular to a method for extracting freeze-dried rose flower extract. Background Technology

[0002] Rose petal extract contains abundant vitamins, amino acids, flavonoids, polyphenols and other active ingredients. In the cosmetics field, it can be used to make skin care products such as moisturizing, whitening and anti-aging products. In the pharmaceutical field, it has medicinal value such as regulating qi and relieving depression, promoting blood circulation and removing blood stasis. In the food field, it can be used as a natural additive and has extremely high application value.

[0003] However, current common methods for extracting rose petal extract have several shortcomings. High-temperature distillation, due to the high temperature, can destroy heat-sensitive components such as vitamins and amino acids in the extract, leading to a decrease in its efficacy. Solvent extraction typically uses organic solvents such as ethanol and acetone, which may remain in the extract, affecting its purity and safety, and also resulting in low extraction rates for some less lipid-soluble active ingredients. Pressing can cause mechanical damage to rose cells, leading to oxidation and deterioration of some active ingredients, and also results in a relatively low extraction rate. Therefore, there is a need for an extraction method that can effectively preserve the active ingredients in fresh rose petals, improve the extraction rate, and ensure the safety of the extract. Summary of the Invention

[0004] The purpose of this invention is to provide a method for extracting freeze-dried rose petal extract.

[0005] A method for extracting freeze-dried rose petal extract includes the following steps: S1. Pretreatment: Select fresh, disease-free rose petals, remove calyxes and stems, and ultrasonically clean them 2-3 times with a mixture of deionized water containing citric acid, vitamin C, and EDTA-2Na. After draining, monitor the moisture content using near-infrared spectroscopy to control it at 86%-88%. S2. Freeze-drying treatment: The fresh roses treated in S1 are laid flat on the freeze-drying tray of the freeze-drying equipment for segmented variable temperature freeze-drying treatment, with a thickness of 5-8cm. S3. Pulverization and enzymatic hydrolysis: After pretreatment with 300MPa ultra-high pressure, freeze-dried roses are pulverized to 10-20μm at 0-5℃ for 5-8 minutes. A complex enzyme composed of cellulase, pectinase and xylanase is added in a mass ratio of 3:2:1. Enzymatic hydrolysis is carried out at pH 4.5-5 and 35℃-40℃ for 30-60 minutes. S4. Extraction process: Mix natural deep eutectic solvent NADES, choline chloride-glycerol, deionized and ethanol solutions to prepare mixed solution C, and then ultrasonically extract the mixed freeze-dried rose powder with mixed solution C for 2-4 hours. S5. Filtration and purification: After centrifuging at 8000 r / min for 10-15 minutes, the extract is filtered sequentially through a 200-mesh filter cloth, a 0.45 μm ceramic membrane, and a 0.22 μm polyethersulfone membrane, and then purified through an AB-8 macroporous resin column. S6. Concentration and Stabilization: First, freeze the purified solution at -5℃ for 12-15 hours, centrifuge to remove water, then concentrate under reduced pressure at 0.085MPa and 42℃ to a relative density of 1.05-1.10. Add 0.15%-0.20% rosemary extract, 0.2%-0.5% β-cyclodextrin and 0.05%-0.08% sodium hyaluronate and mix to obtain the final product.

[0006] Furthermore, the citric acid content in the deionized water mixture in S1 is 0.1%-0.3%, the vitamin C content is 0.05%-0.08%, and the EDTA-2Na content is 0.02%-0.04%.

[0007] Furthermore, the segmented variable-temperature freeze-drying process in S2 is as follows: first, the internal temperature is lowered to -50℃ to -45℃ at a rate of -50℃ / h, then lowered to -40℃ to -35℃ at a rate of -10℃ / h, frozen for 2-3 hours, and then evacuated to 10-20Pa. With the assistance of a 300W microwave, the internal temperature is raised to 30-35℃ at a rate of 5℃ / h over 8-10 hours until the moisture content is ≤2%-4%. Further, the extraction process in S4 is as follows: NADES, a natural deep eutectic solvent, is mixed with choline chloride-glycerol at a molar ratio of 1:2-2.5 to prepare mixed solution A. After dissolving in 50% deionized water, mixed solution B is prepared. Mixed solution B is then mixed with 50%-65% ethanol solution at a volume ratio of 1:4-5 to prepare mixed solution C. Freeze-dried rose powder is mixed with mixed solution C at a material-to-liquid ratio of 1:15-1:20 g / mL. The mixture is then ultrasonically extracted for 2-4 hours in a 3L-5L ultrasonic extractor at 40-45℃ and 300-350W. Furthermore, the ultrasonic cleaning parameters in S1 are 200W, 40kHz, cleaning time 2-5 minutes, and water temperature controlled at 10℃-15℃.

[0008] Furthermore, the total amount of compound enzymes added in S3 is 1.2%-1.5% of the mass of freeze-dried rose powder, including cellulase activity of 10000U / g, pectinase activity of 8000U / g, and xylanase activity of 6000U / g.

[0009] Furthermore, the duty cycle of pulsed ultrasound in S4 is 30%-35%, the microwave frequency is 2450MHz, and the temperature fluctuation during synergistic extraction is controlled within ±1℃.

[0010] Furthermore, the elution flow rate of the AB-8 macroporous resin column in S5 is 1.5 BV / h, the eluent is 55%-58% aqueous ethanol solution, and the transmittance of the collected eluent is ≥98%.

[0011] Furthermore, the total time for combined freezing-reduced pressure concentration in S6 is controlled within 4-5 hours, and the relative density of the concentrated original solution is 1.08-1.10 at 25℃.

[0012] Furthermore, the rose varieties in S1 are Damask roses or Pingyin roses.

[0013] Compared with the prior art, the beneficial effects of the present invention are: 1. Based on the original deionized water rinsing, the cleaning solution composition was optimized to be: deionized water + 0.1% citric acid + 0.05% vitamin C + 0.02% EDTA-2Na. Citric acid inhibits the activity of polyphenol oxidase, vitamin C blocks the oxidation chain reaction, and EDTA-2Na chelates metal ions to prevent them from catalyzing oxidation. The three work together to reduce the oxidation rate of active ingredients to below 5%.

[0014] 2. By introducing the "ultra-high pressure cell disruption + pulsed ultrasound-microwave synergistic extraction" technology, combined with NADES-ethanol composite solvent, the extraction rate is increased to 33.5%-35.2%, which is more than twice that of solvent extraction and pressing methods, and the extraction time is shortened to 2-3 hours. After multi-stage treatment of "centrifugation-gradient membrane filtration-macroporous resin purification", the transmittance of the original solution is increased from 85% to 98%, the removal rate of pigments and sugar impurities reaches 90%, and the loss rate of active ingredients is <3%, and the purity meets the requirements of high-end fields such as cosmetics and food.

[0015] 3. Food-grade solvents are used throughout the process, and solvent residue is reduced to <0.1% through vacuum concentration, avoiding the safety hazards of traditional solvent extraction methods; multi-stage filtration achieves a sterilization rate of 99.2%, and microbiological indicators meet national standards.

[0016] The addition of a complex stabilizer consisting of rosemary extract, β-cyclodextrin, and sodium hyaluronate, combined with freeze-depressurization concentration technology, extends the shelf life to 18 months at 4°C, solving the problems of easy oxidation and short shelf life of the original solution.

[0017] 4. The process parameters are precise and controllable, with a relative standard deviation of less than 5% between two experiments, and an extraction rate fluctuation of ≤2% during scale-up production, making it suitable for large-scale industrial production.

[0018] By "solvent recovery + full utilization of by-products", production costs are reduced by 30% while waste emissions are reduced, which is in line with the concept of green production.

[0019] 5. It is applicable to multiple varieties such as Damask rose and Pingyin rose, and each process step, such as the crushing particle size and ultrasonic power, freeze-drying parameters and extraction efficiency, is matched in a coordinated manner. Even under extreme parameter conditions, the extraction rate can still be maintained at ≥31.8%, and the stability is significantly better than that of traditional processes. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example 1

[0021] (1) Pretreatment Fresh, disease-free Damask roses were selected, and impurities such as calyxes and stems were removed. The roses were then ultrasonically washed twice with a deionized water mixture, and after draining, the moisture content of the fresh flowers was controlled at 86%. The deionized water mixture consisted of deionized water, 0.1% citric acid, 0.05% vitamin C, and 0.02% EDTA-2Na. Citric acid inhibited polyphenol oxidase activity, vitamin C blocked the oxidation chain reaction, and EDTA-2Na chelated metal ions, preventing their catalytic oxidation. These three components synergistically reduced the oxidation rate of active ingredients to below 5%. Ultrasonic cleaning at 200W and 40kHz for 2 minutes was used to utilize cavitation to remove tiny dust particles and microorganisms from the petal surface. The water temperature was controlled at 10℃. After draining, near-infrared spectroscopy was used to monitor the moisture content in real time, ensuring precise control at 86%. This prevented excessively high moisture content from causing prolonged freeze-drying time or excessively low moisture content from causing petal wrinkling.

[0022] (2) Segmented variable temperature freeze drying treatment Stage 1: Gradient freezing. The treated Damask roses are spread evenly on a freeze-drying tray with a thickness of 5 cm and placed in a vacuum freeze dryer. The cold trap temperature is first lowered to -50℃ at a rate of -50℃ / h, and then lowered to -40℃ at a rate of -10℃ / h. The freezing time is shortened to 2 hours.

[0023] Phase 2: Step-by-Step Enhancement After evacuating to 10Pa, the microwave power is adjusted to 300W and the temperature is increased at a rate of 5℃ / h, reaching 30℃ within 8 hours. The microwave penetration accelerates the sublimation of internal moisture, and the water content can be stably reduced to below 2%, while the porous structure of the petals is more complete.

[0024] (3) Low-temperature pulverization and enzymatic hydrolysis pretreatment Pulverization: Pulverize at 0℃ for 5 minutes to obtain freeze-dried rose powder with a particle size of 10-20μm; Synergistic enzymatic hydrolysis: Add cellulase (activity 10000 U / g) at 0.6% of the weight of freeze-dried rose powder, pectinase (activity 8000 U / g) at 0.4% of the weight of freeze-dried rose powder, and xylanase at 0.2% of the weight of freeze-dried rose powder. After mixing, adjust the pH to 4.5 with citric acid and enzymatically hydrolyze for 60 minutes in a 35℃ water bath.

[0025] (4) Ultrasonic extraction using natural deep eutectic solvent NADES-ethanol composite solvent Preparation of composite solvent: Mixed solution A is prepared by mixing natural eutectic solvent NADES with choline chloride-glycerol at a molar ratio of 1:2. Mixed solution B is prepared by dissolving the mixture in 50% deionized water. Mixed solution B is then mixed with 55% ethanol at a volume ratio of 1:4 to prepare mixed solution C. NADES is used as the extraction solvent to enhance the solubility of flavonoids and polyphenols, while ethanol assists in the dissolution of fat-soluble components. It should be noted that natural eutectic solvent is abbreviated as NADES.

[0026] Extraction parameters: Mix freeze-dried rose powder and mixed solution C at a material-to-liquid ratio of 1:15 g / mL, and extract for 3 hours at 40℃ and 300W in a 5L ultrasonic extractor. The combination of enzymatic hydrolysis and ultrasonic extraction improved the extraction rate by 15%-20% compared with the original method.

[0027] (5) Multi-stage filtration and purification The extract was first centrifuged at 8000 r / min for 10 minutes at 4℃ to remove 70% of large particulate impurities, and then filtered sequentially through a 200-mesh filter cloth, a 0.45 μm ceramic membrane, and a 0.22 μm polyethersulfone membrane to obtain a clear solution. Ceramic membranes exhibit superior fouling resistance compared to traditional filter membranes, extending their service life by three times; centrifugal pretreatment increases membrane flux by 50% and prevents clogging.

[0028] The clarified solution was purified by passing it through an AB-8 macroporous resin column and eluted with 55% ethanol, which removed 90% of pigments and sugar impurities. The transmittance of the original solution increased from 85% to 98%, and the loss rate of active ingredients was less than 3%.

[0029] Stabilization Concentration First, the purified solution was frozen at -5℃ for 12 hours to precipitate ice crystals. After centrifugation to remove 60% of the water, it was concentrated under reduced pressure at 0.085 MPa and 42℃ to a relative density of 1.05. By avoiding high temperatures during the freezing and concentration stage, the vitamin C retention rate is increased by 10%, and the total time is reduced to 4 hours.

[0030] After concentration, add 0.15% rosemary extract + 0.2% β-cyclodextrin + 0.05% sodium hyaluronate: Rosemary extract provides antioxidant benefits, β-cyclodextrin encapsulates easily oxidized components, and sodium hyaluronate enhances system stability. Under conditions of storage at 4°C, the shelf life of the concentrate can be extended to 18 months.

[0031] (7) By-product recovery The pretreatment stage employs low-temperature vacuum distillation at 30°C to collect rose essential oil for use in the high-end fragrance industry.

[0032] After filtration and enzymatic hydrolysis, the residue is washed and dried, then processed into rose dietary fiber tablets using extrusion puffing technology, with a total dietary fiber content of 85%, or fermented to produce rose probiotic powder with a live lactic acid bacteria count ≥10. 9 CFU / g.

[0033] The ethanol vapor generated during the extraction and concentration stages is recovered by condensation-distillation, with a purity of ≥95% and a recovery rate of 90%, reducing production costs by 30%.

[0034] Testing revealed that the optimized method yielded a stock solution containing 16.5 mg / 100 mL of vitamin C and 10.5 mg / 100 mL of total flavonoids, with an extraction rate of 33.5%. Furthermore, the shelf life was extended to 18 months, significantly enhancing the technological competitiveness. Repeating the above experimental steps yielded an extraction rate of 33.8%. Example 2

[0035] (1) Pretreatment Fresh, disease-free Damask roses were selected, and impurities such as calyxes and stems were removed. The roses were then ultrasonically cleaned three times with a deionized water mixture, drained, and the moisture content of the fresh flowers was controlled at 88%. The deionized water mixture consisted of: deionized water + 0.3% citric acid + 0.08% vitamin C + 0.04% EDTA-2Na. Ultrasonic cleaning was performed at 200W and 40kHz for 5 minutes, while maintaining a water temperature of 15℃.

[0036] (2) Segmented variable temperature freeze drying treatment Stage 1: Gradient freezing. The treated Damask roses are spread evenly on a freeze-drying tray with a thickness of 8 cm and placed in a vacuum freeze dryer. The cold trap temperature is first lowered to -45℃ at a rate of -50℃ / h, and then lowered to -35℃ at a rate of -10℃ / h, shortening the freezing time to 3 hours.

[0037] Phase 2: Step-by-Step Enhancement After evacuating to 20 Pa, the microwave power was adjusted to 300 W, and the temperature was increased at a rate of 5 °C / h, reaching 35 °C within 10 hours.

[0038] (3) Low-temperature pulverization and enzymatic hydrolysis pretreatment Pulverization: Pulverize at 5℃ for 8 minutes to obtain freeze-dried rose powder with a particle size of 10-20μm; Synergistic enzymatic hydrolysis: Add cellulase (activity 10000 U / g) at 0.75% of the weight of freeze-dried rose powder, pectinase (activity 8000 U / g) at 0.5% of the weight of freeze-dried rose powder, and xylanase at 0.25% of the weight of freeze-dried rose powder. After mixing, adjust the pH to 5 with citric acid and enzymatically hydrolyze for 30 minutes in a 40℃ water bath.

[0039] (4) Ultrasonic extraction using natural deep eutectic solvent NADES-ethanol composite solvent Preparation of composite solvent: The natural eutectic solvent NADES is mixed with choline chloride-glycerol at a molar ratio of 1:2, dissolved in 50% deionized water, and then mixed with 55% ethanol at a volume ratio of 1:4. NADES is used as the extraction solvent to enhance the solubility of flavonoids and polyphenols, while ethanol assists in the dissolution of fat-soluble components. It should be noted that the natural eutectic solvent is abbreviated as NADES.

[0040] Extraction parameters: freeze-dried rose powder and compound solvent were mixed at a material-to-liquid ratio of 1:20 g / mL and ultrasonically extracted for 3 hours at 40℃ and 300W in a 5L ultrasonic extractor. The combination of enzymatic hydrolysis and ultrasonic extraction improved the extraction rate by 15%-20% compared with the original method.

[0041] (5) Multi-stage filtration and purification The extract was centrifuged at 8000 r / min for 15 minutes at 4℃, and then filtered sequentially through a 200-mesh filter cloth, a 0.45 μm ceramic membrane, and a 0.22 μm polyethersulfone membrane to obtain a clear solution. The clarified solution was purified by passing it through an AB-8 macroporous resin column and eluted with 58% ethanol.

[0042] Stabilization Concentration The purified solution was first frozen at -5°C for 15 hours to precipitate ice crystals, and then concentrated under reduced pressure at 0.085 MPa and 42°C to a relative density of 1.10. After concentration, add 0.20% rosemary extract, 0.5% β-cyclodextrin, and 0.08% sodium hyaluronate and mix.

[0043] Testing revealed that the optimized method yielded a stock solution containing 17.1 mg / 100 mL of vitamin C and 11.4 mg / 100 mL of total flavonoids, with an extraction rate of 34.2%. Furthermore, the shelf life was extended to 18 months, significantly enhancing the technological competitiveness. Repeating the above experimental steps yielded an extraction rate of 34.1%. Example 3

[0044] (1) Pretreatment Fresh, disease-free Damask roses were selected, and impurities such as calyxes and stems were removed. The roses were then ultrasonically cleaned twice with a deionized water mixture, drained, and the moisture content of the fresh flowers was controlled at 87%. The deionized water mixture consisted of: deionized water + 0.2% citric acid + 0.06% vitamin C + 0.03% EDTA-2Na. Ultrasonic cleaning was performed at 200W and 40kHz for 3 minutes, while maintaining a water temperature of 12℃.

[0045] (2) Segmented variable temperature freeze drying treatment Stage 1: Gradient freezing. The treated Damask roses are spread evenly on a freeze-drying tray with a thickness of 7cm and placed in a vacuum freeze dryer. The cold trap temperature is first lowered to -48℃ at a rate of -50℃ / h, and then lowered to -32℃ at a rate of -10℃ / h, shortening the freezing time to 2 hours.

[0046] Phase 2: Step-by-Step Enhancement After evacuating to 15 Pa, the microwave power was adjusted to 300 W, and the temperature was increased at a rate of 5 °C / h, reaching 32 °C within 9 hours.

[0047] (3) Low-temperature pulverization and enzymatic hydrolysis pretreatment Pulverization: Pulverize at 3℃ for 7 minutes to obtain freeze-dried rose powder with a particle size of 10-20μm; Synergistic enzymatic hydrolysis: Add cellulase (activity 10000 U / g) at 0.66% of the weight of freeze-dried rose powder, pectinase (activity 8000 U / g) at 0.44% of the weight of freeze-dried rose powder, and xylanase at 0.22% of the weight of freeze-dried rose powder. After mixing, adjust the pH to 5 with citric acid and enzymatically hydrolyze in a 40℃ water bath for 30 minutes.

[0048] (4) Ultrasonic extraction using natural deep eutectic solvent NADES-ethanol composite solvent Preparation of composite solvent: The natural eutectic solvent NADES is mixed with choline chloride-glycerol at a molar ratio of 1:2, dissolved in 50% deionized water, and then mixed with 55% ethanol at a volume ratio of 1:4. NADES is used as the extraction solvent to enhance the solubility of flavonoids and polyphenols, while ethanol assists in the dissolution of fat-soluble components. It should be noted that the natural eutectic solvent is abbreviated as NADES.

[0049] Extraction parameters: freeze-dried rose powder and compound solvent were mixed at a material-to-liquid ratio of 1:18 g / mL and ultrasonically extracted for 3 hours at 40℃ and 300W in a 5L ultrasonic extractor. The combination of enzymatic hydrolysis and ultrasonic extraction improved the extraction rate by 15%-20% compared with the original method.

[0050] (5) Multi-stage filtration and purification The extract was centrifuged at 8000 r / min for 13 minutes at 4℃, and then filtered sequentially through a 200-mesh filter cloth, a 0.45 μm ceramic membrane, and a 0.22 μm polyethersulfone membrane to obtain a clear solution. The clarified solution was purified by passing it through an AB-8 macroporous resin column and eluted with 56% ethanol.

[0051] Stabilization Concentration The purified solution was first frozen at -5°C for 13 hours to precipitate ice crystals, and then concentrated under reduced pressure at 0.085 MPa and 42°C to a relative density of 1.08. After concentration, add 0.16% rosemary extract, 0.3% β-cyclodextrin, and 0.07% sodium hyaluronate and mix.

[0052] Testing revealed that the optimized method yielded a stock solution containing 16.8 mg / 100 mL of vitamin C and 10.9 mg / 100 mL of total flavonoids, with an extraction rate of 33.7%. Furthermore, the shelf life was extended to 18 months, significantly enhancing the technological competitiveness. Repeating the above experimental steps yielded an extraction rate of 33.8%. Example 4

[0053] (1) Fresh Pingyin roses were used for extraction according to the process in Example 1. The results showed that the vitamin C content was 14.8 mg / 100 mL, the total flavonoid content was 9.5 mg / 100 mL, and the extraction rate was 32.1%. This method is applicable to different rose varieties. Repeating the above extraction operation yielded an extraction rate of 31.8%. Example 5

[0054] (1) The capacity of the ultrasonic extractor was increased from 5L to 50L. Using a 50L ultrasonic extractor, production was scaled up according to the parameters of Example 1. The extraction rate was 29.8%, RSD=0.8%, and the content of active ingredients deviated from the laboratory scale by ≤2%. The above extraction operation was repeated to obtain an extraction rate of 30.3%.

[0055] Comparative Example 1 uses high-temperature distillation method Pretreatment: Same as in Example 1, select the same type of fresh roses, and the water content after treatment is 86%.

[0056] Distillation: Place fresh rose petals in a distillation apparatus, add deionized water at a ratio of 1:15 (g / mL), heat to boiling, and distill for 4 hours at a gentle boil. Collect the distillate.

[0057] Filtration and concentration: The distillate is filtered through a 200-mesh filter cloth and then concentrated under reduced pressure at 60°C to a relative density of 1.08 at a temperature of 25°C.

[0058] The original solution was found to contain 3.2 mg / 100 mL of vitamin C, 2.8 mg / 100 mL of total flavonoids, and an extraction rate of 12.5%.

[0059] Comparative Example 2 uses solvent extraction method Pretreatment: Same as in Example 1, with the water content of fresh roses at 86%.

[0060] Extraction process: Fresh rose petals were crushed to a particle size of 50 μm, and 70% ethanol aqueous solution was added at a material-to-liquid ratio of 1:15 (g / mL). The mixture was stirred and extracted at room temperature for 6 hours.

[0061] Filtration and concentration: After filtration through a 200-mesh filter cloth, the mixture was concentrated under reduced pressure at 50°C to a relative density of 1.08 at a temperature of 25°C, and the residual ethanol content was found to be 0.5%.

[0062] The original solution was found to contain 7.5 mg / 100 mL of vitamin C, 5.2 mg / 100 mL of total flavonoids, and an extraction rate of 18.3%.

[0063] Comparative Example 3 uses the pressing method Pretreatment: Same as in Example 1, with the water content of fresh roses at 86%.

[0064] Pressing process: Press fresh rose petals with a press and collect the press liquid.

[0065] Filtration: The original liquid was obtained by filtration through a 200-mesh filter cloth, with a relative density of 1.08 and a temperature of 25℃.

[0066] The original solution was tested and found to contain 4.8 mg / 100 mL of vitamin C, 3.5 mg / 100 mL of total flavonoids, and an extraction rate of 9.8%.

[0067] Comparative Example 4: Freeze-dried product extracted directly without pulverization Except for omitting the above pulverization step and directly using freeze-dried whole flowers, the rest is the same as in Example 1. The results are: extraction rate of 18.3%, vitamin C 8.2mg / 100mL, and total flavonoids 5.1mg / 100mL; proving the synergistic effect of "freeze-drying + pulverization", which increased the extraction rate by 56%, rather than the effect of freeze-drying alone.

[0068] Comparative Example 5: Non-ultrasonic extraction A constant temperature water bath at 42℃ was used instead of ultrasound, and the rest was the same as in Example 1. The extraction time was extended to 6 hours. The results showed that the extraction rate was 20.5% and the content of active ingredients decreased by 18%. This proves the irreplaceable nature of ultrasound extraction, which improves efficiency by 2 times and preserves activity better.

[0069] Comparative Example 6: Traditional freeze-drying + conventional extraction The sample was freeze-dried at -30℃, undiluted, and extracted with 70% ethanol at room temperature for 6 hours. The results showed that the vitamin C content was 6.8 mg / 100 mL, the total flavonoids were 4.5 mg / 100 mL, and the extraction rate was 15.2%, further verifying the irreplaceable nature of the process of this invention.

[0070] The following conclusions were reached: Each embodiment of this invention underwent two experiments, and the relative standard deviations of the experimental results were all less than 5%, indicating good experimental repeatability. Vitamin C content was determined using high-performance liquid chromatography (HPLC) according to GB / T6195-1986, and total flavonoid content was determined using ultraviolet spectrophotometry with rutin as a reference standard. The extraction rate was calculated by accurately weighing the raw materials and the solids in the final stock solution. All detection methods complied with relevant national standards, and the data are accurate and reliable. Detailed extraction rates are shown in Table 1 below.

[0071] Comparative analysis with the comparative examples revealed that Comparative Example 1 suffered significant damage to heat-sensitive components due to high temperature, resulting in low active ingredient content and extraction rate. While Comparative Example 2 achieved a higher extraction rate than distillation and pressing methods, residual ethanol affected safety, and the retention of active ingredients was inferior to that of this invention. Comparative Example 3 exhibited the lowest extraction rate due to oxidation of active ingredients caused by mechanical damage. This invention, through a lyophilization-ultrasound synergistic process, demonstrates significant advantages in preserving active ingredients and improving extraction rate.

[0072] Experimental data show that, through the synergistic processes of vacuum freeze-drying, low-temperature pulverization, and ultrasonic extraction, this invention achieves the following results compared to traditional methods: in terms of retention of active ingredients, the content of vitamin C and total flavonoids is increased by 3-4 times; in terms of extraction efficiency, the extraction rate is increased to 34.2%, which is about 3 times that of traditional methods.

[0073] The extraction method is as follows: Vacuum freeze-drying removes moisture from fresh rose petals under low temperature and vacuum conditions, avoiding the damage to heat-sensitive active ingredients such as vitamins, amino acids, and flavonoids caused by high temperatures. As shown in the examples, the extract obtained by this method has a higher content of vitamin C and total flavonoids, significantly higher than that obtained by traditional high-temperature distillation, proving that this method effectively preserves the active ingredients.

[0074] Freeze-dried rose petals have a loose texture and a porous structure. After ultra-fine pulverization, the particle size is small, resulting in a large contact area with the extraction solvent. Combined with the cavitation effect and mechanical vibration of ultrasonic extraction, the active ingredients can be fully dissolved. The extraction rates in Examples 1-3 reached 33.5%-34.2%, which is significantly higher than that of traditional solvent extraction and pressing methods.

[0075] The extraction solvent uses food-grade ethanol, which is evaporated during the concentration process, leaving no organic solvent residue. The filtration step uses a microporous membrane to remove microorganisms and tiny particles, ensuring the purity and safety of the original solution, which can be directly used in cosmetics, food and other fields.

[0076] Simple to operate and easy to industrialize: Each step of this method uses conventional equipment, such as vacuum freeze dryers, ultrafine pulverizers, ultrasonic extractors, rotary evaporators, etc. The equipment is readily available, the operation process is simple, and the parameters are easy to control, making it suitable for large-scale industrial production.

[0077] In summary, the freeze-dried rose flower extract extraction method of the present invention can effectively retain the active ingredients in rose flowers, improve the extraction rate, and ensure the purity and safety of the extract, and has broad application prospects.

[0078] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only to the claims and their full scope and equivalents.

Claims

1. A method for extracting freeze-dried rose flower extract, characterized in that, Includes the following steps: S1. Pretreatment: Select fresh, disease-free rose petals, remove calyxes and stems, and ultrasonically clean them 2-3 times with a mixture of deionized water containing citric acid, vitamin C, and EDTA-2Na. After draining, monitor the moisture content using near-infrared spectroscopy to control it at 86%-88%. S2. Freeze-drying treatment: The fresh roses treated in S1 are laid flat on the freeze-drying tray of the freeze-drying equipment for segmented variable temperature freeze-drying treatment, with a thickness of 5-8cm. S3. Pulverization and enzymatic hydrolysis: After pretreatment with 300MPa ultra-high pressure, freeze-dried roses are pulverized to 10-20μm at 0-5℃ for 5-8 minutes. A complex enzyme composed of cellulase, pectinase and xylanase is added in a mass ratio of 3:2:

1. Enzymatic hydrolysis is carried out at pH 4.5-5 and 35℃-40℃ for 30-60 minutes. S4. Extraction process: Mix natural deep eutectic solvent NADES, choline chloride-glycerol, deionized and ethanol solutions to prepare mixed solution C, and then ultrasonically extract the mixed freeze-dried rose powder with mixed solution C for 2-4 hours. S5. Filtration and purification: After centrifuging at 8000 r / min for 10-15 minutes, the extract is filtered sequentially through a 200-mesh filter cloth, a 0.45 μm ceramic membrane, and a 0.22 μm polyethersulfone membrane, and then purified through an AB-8 macroporous resin column. S6. Concentration and Stabilization: First, freeze the purified solution at -5℃ for 12-15 hours, centrifuge to remove water, then concentrate under reduced pressure at 0.085MPa and 42℃ to a relative density of 1.05-1.

10. Add 0.15%-0.20% rosemary extract, 0.2%-0.5% β-cyclodextrin and 0.05%-0.08% sodium hyaluronate and mix to obtain the final product.

2. The extraction method according to claim 1, characterized in that, The deionized water mixture in S1 contains 0.1%-0.3% citric acid, 0.05%-0.08% vitamin C, and 0.02%-0.04% EDTA-2Na.

3. The extraction method according to claim 1, characterized in that, The specific steps of the S2 segmented variable temperature freeze-drying process are as follows: First, the internal temperature of the chamber is lowered to -50℃ to -45℃ at a rate of -50℃ / h, then the internal temperature is lowered to -40℃ to -35℃ at a rate of -10℃ / h, frozen for 2-3 hours, and then a vacuum is drawn to 10-20Pa. With the assistance of a 300W microwave, the chamber temperature is raised to 30-35℃ at a rate of 5℃ / h within 8-10 hours until the water content is ≤2%-4%.

4. The extraction method according to claim 1, characterized in that, The extraction process for S4 is as follows: Mix natural eutectic solvent NADES with choline chloride-glycerol at a molar ratio of 1:2-2.5 to prepare mixed solution A. Dissolve the mixture in 50% deionized water to prepare mixed solution B. Mixed solution B is then mixed with 50%-65% ethanol solution at a volume ratio of 1:4-5 to prepare mixed solution C. Freeze-dried rose powder is mixed with mixed solution C at a material-to-liquid ratio of 1:15-1:20 g / mL. The mixture is then ultrasonically extracted for 2-4 hours in a 3L-5L ultrasonic extractor at 40-45℃ and 300-350W.

5. The extraction method according to claim 1, characterized in that, The ultrasonic cleaning parameters in S1 are 200W, 40kHz, cleaning time 2-5 minutes, and water temperature controlled at 10℃-15℃.

6. The extraction method according to claim 1, characterized in that, The total amount of compound enzymes added in S3 is 1.2%-1.5% of the weight of freeze-dried rose powder, including cellulase activity of 10000U / g, pectinase activity of 8000U / g, and xylanase activity of 6000U / g.

7. The extraction method according to claim 1, characterized in that, In S4, the duty cycle of pulsed ultrasound is 30%-35%, the microwave frequency is 2450MHz, and the temperature fluctuation during synergistic extraction is controlled within ±1℃.

8. The extraction method according to claim 1, characterized in that, The elution flow rate of the AB-8 macroporous resin column in S5 is 1.5 BV / h, the eluent is 55%-58% aqueous ethanol solution, and the transmittance of the collected eluent is ≥98%.

9. The extraction method according to claim 1, characterized in that, The total time for combined freezing-reduced pressure concentration in S6 is controlled within 4-5 hours, and the relative density of the concentrated original solution is 1.08-1.10 at 25℃.

10. The extraction method according to claim 1, characterized in that, The rose varieties in S1 are Damask roses or Pingyin roses.

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