Preparation method of peony flower concentrated stock solution rich in aroma components and application thereof in flavors / spices

Abstract

The present invention belongs to the technical field of peony flower processing, and specifically relates to a method for preparing a concentrated peony flower liquid rich in aroma components and its application in flavors and fragrances. The method for preparing the concentrated peony flower liquid is as follows: the peony flowers are sequentially pre-cooled and deep-frozen, then sheared and crushed in a circulating liquid nitrogen atmosphere, followed by enzymatic hydrolysis using ultrasound-assisted biological enzymes to obtain an enzymatic hydrolyzate, and finally, a product enriched liquid with a specific molecular weight is intercepted and concentrated through an ultrafiltration membrane. The present invention pre-cools and deep-freezes the peony flowers, which not only avoids the loss of active substances such as polyphenols and browning of the material, but also helps to maximize the retention of aroma components in fresh petals, avoiding the problem of loss of volatile aroma components caused by pulverization operations at high or room temperatures. The peony flower liquid finally prepared by the present invention contains rich volatile aroma components such as linalool oxide, citronellol, and benzoic acid, and has broad application prospects in skin care products and flavors and fragrances.

Description

Technical Field

[0001] The invention belongs to the technical field of peony flower processing, and particularly relates to a preparation method of a peony flower concentrated stock solution rich in aroma components and application of the concentrated stock solution in essences / spices. Background Art

[0002] Peony flowers are rich in a variety of active ingredients, including polyphenols, flavonoids, and aroma components such as citronellol, geraniol, and benzoic acid. So far, the main reported effects of the active ingredients of peony flowers include: whitening effects such as inhibiting tyrosinase activity, antioxidant effects such as scavenging free radicals, anti-wrinkle effects such as inhibiting elastase activity, anti-glycation effects, anti-inflammatory effects, etc. Therefore, peony flowers are often used as a cosmetic raw material.

[0003] However, during the processing of fresh peony flowers, they generally need to be pulped or crushed before proceeding to the next step. However, due to the soft petals of peony flowers, they easily form clumps or pastes during the crushing process, making it difficult for the active ingredients in them to be fully dissolved. Browning occurs easily during the pulping process, causing the extract to darken in color and requiring additional decolorization steps. At the same time, traditional processing methods easily lead to the volatilization or even destruction and loss of aromatic components in peony flowers, such as linalool oxide and benzoic acid.

[0004] This problem can be solved by cryogenic grinding. Since the material reaches a brittle state during the low-temperature (≤-20°C) grinding and wall-breaking process, peony flower powder with a smaller crushed particle size (below 200~300 mesh) can be obtained, avoiding the loss of active substances. At the same time, it can prevent the material from browning and deepening in color, which is beneficial to improving the solubility and bioavailability of small molecule functional substances in cells and retaining the aroma components in peony flowers as much as possible.

[0005] Although low-temperature freezing can make peony flowers brittle and easier to grind into powder, their solid content is still not ideal, which means that the active ingredients are still retained to a large extent.

[0006] In order to obtain the active ingredients in peony flowers to the greatest extent and avoid their loss during processing, the existing processing technology needs to be improved. Summary of the Invention

[0007] In order to solve the above technical problems, the present invention provides a method for preparing a concentrated peony flower stock solution rich in aroma components and its application in flavors / spices.

[0008] The method for preparing the peony flower concentrated stock solution rich in aroma components provided by the present invention comprises the following steps:

[0009] (1) Take fresh peony flowers, pre-cool them at -20~-18℃ for 4~6 hours, and then deep freeze them at -55~-45℃ for 4~6 hours. Take the frozen peony flowers and shear and crush them in a circulating liquid nitrogen atmosphere. The temperature of the liquid nitrogen in the crushing equipment cavity and pipeline is the same as the cryogenic temperature, which is -55~-45℃. Sieve the powder to obtain peony flower full powder with a particle size of less than 50 μm.

[0010] (2) taking the peony flower powder obtained in (1), adding a complex enzyme and performing enzymatic hydrolysis under ultrasonication to obtain an enzymatic hydrolyzate;

[0011] Based on the weight of dry peony flower powder, the addition amounts of cellulase and neutral protease in the complex enzyme are 20-30 U / g and 20-50 U / g, respectively;

[0012] (3) Centrifuging the enzymatic hydrolysate obtained in (2), retaining the supernatant, and filtering the supernatant using an ultrafiltration membrane to obtain a product enrichment solution;

[0013] (4) The product enrichment solution obtained in (3) is subjected to low-temperature vacuum film concentration, sterilization, and filtration to obtain a peony flower concentrated stock solution rich in aroma components.

[0014] The present invention utilizes a pre-cooling combined with cryogenic pulverization process to treat fresh peony flowers. This, on the one hand, facilitates the dissolution of active ingredients from the fresh peony flowers. On the other hand, since fresh peony flowers contain a large number of aroma components, most of which are highly volatile and sensitive to high temperatures, high-temperature treatment inevitably results in significant losses due to volatilization. Even pulverization at room temperature also results in significant losses of volatile aroma components. Therefore, the present invention utilizes a combination of pre-cooling and cryogenic pulverization to "lock in" the aroma components, maximizing their retention during pulverization, thereby retaining as many of these volatile aroma components as possible in the resulting peony flower concentrated liquid.

[0015] In the above-mentioned method for preparing the concentrated peony flower stock solution rich in aroma components, preferably, in (2), before using the composite enzyme for enzymatic hydrolysis, citric acid buffer is first added at a material-liquid mass ratio of 1:4-6, and the pH value of the mixed solution is adjusted to 5.5-6.5.

[0016] The complex enzyme was used for enzymatic hydrolysis at room temperature for 1-3 h. Ultrasonic treatment was performed 1-3 times during the enzymatic hydrolysis process. Each ultrasonic treatment was performed for 0.5 h and then another ultrasonic treatment was performed at an interval of 0.5 h. The ultrasonic power was 20-50 kHz.

[0017] Preferably, the refrigerated centrifugation described in (3) has a centrifugal speed of 8000-10000 rpm, a centrifugal time of 10-15 min, and a temperature of 0-4°C.

[0018] Preferably, in (3), the supernatant is retained by an ultrafiltration membrane to obtain a product enriched solution with a molecular weight cut-off of less than 6000 Da.

[0019] Preferably, the low-temperature vacuum thin film concentration described in (4) has an evaporation temperature of ≤50°C, and is concentrated to 1 / 4 to 1 / 6 of the volume of the enriched liquid, and then a citric acid buffer is added to adjust the pH value to 5.5 to 6.0.

[0020] Preferably, the sterilization temperature described in (4) is 65-85°C, and the sterilization time is 15-30 min.

[0021] In addition, the present invention also provides a product containing the above-mentioned concentrated peony flower solution rich in aroma components, wherein the product is obtained by adding a product stability enhancer to the concentrated peony flower solution rich in aroma components and stirring the mixture uniformly, wherein 2 to 5 g of the product stability enhancer is added to every 100 mL of the concentrated peony flower solution rich in aroma components.

[0022] Preferably, the product stability enhancer is prepared by the following method:

[0023] Add 20-40 mL of peony seed oil, 3-5 g of sodium lactate, and 100 mL of water into a reaction tank, stir and heat to 60-80°C, then add 0.4-0.6 g of ε-polylysine hydrochloride and 2-3 g of methyl hydroxybenzoate, stir, then add citric acid buffer, adjust the pH to 5.5-6.0, then add 10-20 g of chitosan, stir evenly, and cool to room temperature to prepare a stability enhancer.

[0024] Furthermore, the application of the peony flower concentrated liquid rich in aroma components or the above-mentioned product in skin care products is also the key protection content of the present invention.

[0025] In addition, the use of the peony flower concentrated liquid rich in aroma components or the above-mentioned product in flavors / spices also falls within the scope of protection of the present invention.

[0026] The beneficial effects of the present invention are:

[0027] (1) The present invention uses a combination of pre-cooling and deep-cold crushing to treat peony flowers, which not only significantly increases the solid content in the extract and promotes the dissolution of active ingredients, but most importantly, can maximize the retention of volatile aroma components in peony flowers;

[0028] For example, in the concentrated peony flower liquid obtained by extraction using the method of the present invention, the content of linalool oxide in its aroma components can reach 7.32%, citronellol, geraniol, and benzoic acid account for 0.84%, 0.93%, and 0.77%, respectively. In addition, the total flavonoid content can reach 25.79%. The total flavonoid content reflects the high content of active ingredients on the one hand, and on the other hand, the total flavonoids also contain some volatile aroma components. The high content of these flavonoids also means that the content of volatile aroma components will also be correspondingly high.

[0029] (2) During the enzymatic hydrolysis of peony flower powder, the effect of ultrasound was used to further break the matrix barrier that hindered the dissolution of active ingredients, strengthen the mass transfer of powder, and promote the dissolution of active ingredients. At the same time, the macromolecular components such as fiber and protein in the matrix could be decomposed into oligosaccharides, short peptides and amino acids under the action of ultrasound, further improving the biological activity of the enzymatic hydrolysate.

[0030] (3) By comparing the enrichment effects of ultrafiltration membranes of different specifications on active ingredients, the ultrafiltration membrane that is relatively most conducive to the enrichment of active ingredients was selected. The experimental results showed that the product fraction of ≤6000Da obtained by ultrafiltration membrane interception had an inhibition rate of 73.23% on tyrosinase, an inhibition rate of 50.19% on cell melanin production, and an inhibition rate of 63.45% on cell secretion of TNF-α. It has a better whitening effect than products with other molecular weights. In addition, the concentrate is rich in aroma components. Therefore, the peony flower concentrated concentrate or product provided by the present invention has good application prospects in skin care products, cosmetics, essences, fragrances and other products.

[0031] (4) The present invention also provides a product stability protecting agent. By adding the product stability protecting agent to the prepared peony flower concentrated liquid rich in aroma components, it helps the product maintain good long-term effect and stability during long-term storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the inhibition curve of the peony flower concentrated solution rich in aroma components prepared in Example 4 of the present invention on tyrosinase activity;

[0033] Figure 2 The results show that the concentrated peony flower solution rich in aroma components prepared in Example 4 of the present invention inhibits melanin synthesis in B16F10 cells at different concentrations;

[0034] Figure 3 The results show that the concentrated peony flower solution rich in aroma components prepared in Example 4 of the present invention inhibits the secretion of TNF-α by RAW264.7 cells at different concentrations;

[0035] Figure 4This is a diagram of the state of peony flower concentrated liquid obtained by different methods after being placed at room temperature for one month. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to better understand the present invention, the present invention will be further explained in conjunction with specific embodiments.

[0037] Example 1

[0038] This example focuses on examining the particle sizes of fresh peony flowers and the content of active ingredients therein obtained at different freezing and pulverization temperatures during the freezing treatment of fresh peony flowers.

[0039] The specific experimental operation of this embodiment is as follows:

[0040] Fresh peony flowers were precooled at -18°C for 5 h, and then deep-frozen for 5 h in the temperature range of -80~-20°C. The frozen peony flowers were sheared and crushed in a circulating liquid nitrogen atmosphere. The temperature in the crushing equipment cavity and pipeline was the same as the crushing temperature, which was -80~-20°C. The powder was sieved to obtain peony flower full micronized powder with a particle size of <50 μm.

[0041] In addition, when the crushing temperature is room temperature (23°C), the peony flowers are no longer pre-cooled or deep-cooled under this condition.

[0042] The particle size of the peony flower micropowder obtained at different cryogenic grinding temperatures and the content of the active ingredients therein are shown in Table 1 below.

[0043] Table 1 Particle size and component yield at different crushing temperatures

[0044] Crushing temperature / ℃ <![CDATA[D 50 / μm]]> <![CDATA[D 90 / μm]]> Polyphenols / mg / g Flavonoids / mg / g Main aroma substances / % Room temperature / 23 386.47 674.70 28.17 5.48 7.54 -20 107.70 237.23 48.59 10.82 8.89 -40 65.74 208.67 62.12 11.82 9.43 -50 45.61 199.53 72.01 12.17 11.76 -60 72.47 237.23 65.12 10.43 11.02 -80 102.23 239.20 59.77 10.05 10.22

[0045] Note: The main aroma substances are calculated based on the contents of linalool oxide, citronellol, geraniol and benzoic acid, the same below.

[0046] Table 1 shows that the particle size of peony flower whole powder obtained at different grinding temperatures is significantly different. At the same time, the content of polyphenols and flavonoids in the whole powder also shows great differences. When the grinding temperature is -50℃, the particle size of the peony flower whole powder obtained is the smallest, and the content of polyphenols and flavonoids in the whole powder is also the highest. When the grinding temperature continues to drop to -60℃ or even -80℃, the particle size of the peony flower whole powder actually increases.

[0047] Therefore, in order to obtain a better pulverization effect, the pulverization temperature is set to -50°C in the present invention.

[0048] Furthermore, the present invention investigates the effects of pre-cooling and cryogenic treatment on the pulverization process, that is, pulverization is performed directly at specific temperatures (i.e., -20°C, -50°C, -80°C) without pre-cooling and cryogenic treatment. The experimental results are shown in Table 2 below.

[0049] Table 2 Particle size and component yield after cryogenic treatment without pre-cooling

[0050] Crushing temperature / ℃ <![CDATA[D 50 / μm]]> <![CDATA[D 90 / μm]]> Polyphenols / mg / g Flavonoids / mg / g Main aroma substances / % -20 343.20 706.9 25.34 5.54 5.31 -50 317.89 642.58 26.07 4.87 6.88 -80 310.73 673.28 28.93 5.88 6.31

[0051] The data in the table show that even at the same crushing temperature, the peony petals that have not been pre-cooled and deep-cooled have larger particle sizes and poor crushing effects. This may be because without pre-cooling and deep-cooling in advance during crushing, the internal and external temperatures of the peony petals are difficult to reach the crushing temperature and undergo glass transition within a short crushing time, thus affecting the crushing effect.

[0052] In addition, the above results also show that pre-cooling, cryogenic treatment and ultrafine grinding at cryogenic temperature have a significant effect on the content of aroma components in the peony flower concentrated liquid. The pre-cooling and cryogenic treatment can effectively "lock" the aroma components, and these aroma components can be retained to the maximum extent during low-temperature grinding, which is beneficial to retaining as many volatile aroma components as possible in the final product, the peony flower concentrated liquid.

[0053] Example 2

[0054] This example focuses on exploring the effect of the enzymatic hydrolysis process of peony whole micronized powder on the extraction of active ingredients from peony flowers. The specific experimental procedures are as follows:

[0055] (1) Take fresh peony flowers, pre-cool them at -18℃ for 5 h, and then deep freeze them at -50℃ for 5 h. Take the frozen peony flowers and shear and crush them in a circulating liquid nitrogen atmosphere. The liquid nitrogen temperature in the crushing equipment cavity and pipeline is -50℃. Sieve the powder to obtain peony flower full powder with a particle size of less than 50 μm.

[0056] (2) The peony flower powder obtained in (1) was treated by the following methods: cellulase treatment only, neutral protease treatment only, cellulase and neutral protease combined enzyme treatment, and ultrasound-assisted combined enzyme treatment.

[0057] The active ingredients in the enzymatic hydrolysates obtained after different treatments are shown in Table 3 below.

[0058] Table 3 Yield of active ingredients in the enzymatic hydrolysates obtained after different enzymatic hydrolysis treatments

[0059] Group Soluble solids / mg / g Polyphenols / mg / g Flavonoids / mg / g Cellulase 20 U / g 409.36 122.83 19.68 Neutral protease 30 U / g 251.28 92.54 13.10 Cellulase 20 U / g + Neutral Protease 30 U / g 541.75 136.47 23.44 Cellulase 50U / g 488.23 143.58 20.98 Neutral protease 50 U / g 379.50 118.32 23.01 Cellulase 20 U / g + neutral protease 30 U / g + ultrasound 709.67 152.64 28.07

[0060] The data in Table 3 show that the enzymatic method combined with ultrasound-assisted operation can make the active ingredients in peony pollen dissolve more fully.

[0061] Example 3

[0062] This example focuses on exploring the retention effect of ultrafiltration membranes of different specifications on peony extract. The specific experimental procedures are as follows:

[0063] (1) Take fresh peony flowers, pre-cool them at -18℃ for 5 h, and then deep freeze them at -50℃ for 5 h. Take the frozen peony flowers and shear and crush them in a circulating liquid nitrogen atmosphere. The liquid nitrogen temperature in the crushing equipment cavity and pipeline is -50℃. Sieve the powder to obtain peony flower full powder with a particle size of less than 50 μm.

[0064] (2) Take the peony flower powder obtained in (1), add citric acid buffer at a material-liquid mass ratio of 1:5, and adjust the pH value of the mixed solution to 6.0. Use complex enzyme to hydrolyze at room temperature for 2 h. During the enzymatic hydrolysis, ultrasonic treatment is performed twice, each ultrasonic treatment is 0.5 h and then ultrasonic treatment is performed again after an interval of 0.5 h. The ultrasonic frequency is 40 kHz to obtain an enzymatic hydrolyzate.

[0065] In the complex enzyme, the addition amount of cellulase and neutral protease was 20 U / g and 30 U / g dry basis peony flower whole micronized powder weight, respectively;

[0066] (3) The enzymatic hydrolysate obtained in (2) was centrifuged at a speed of 8000 rpm for 10 min at 4°C. The supernatant was retained and filtered using ultrafiltration membranes of different specifications (unretained, 3000 Da, 6000 Da, and 10000 Da) to obtain product enrichment solution.

[0067] The activity effects of peony extract concentrated stock solutions obtained by ultrafiltration membranes of different specifications are shown in Table 4 below.

[0068] Table 4 Activity of enriched fractions with different molecular weights

[0069]

[0070] The above results show that peony flower concentrated stock solutions of different molecular weights all have high biological activity. Even for the stock solution without interception operation, its tyrosinase inhibition rate, cell melanin production inhibition rate, and cell TNF-α secretion inhibition rate are all above 52%. When the stock solution is intercepted by ultrafiltration membrane, the activity of the peony flower concentrated stock solution with a specific molecular weight obtained is improved compared with the stock solution. In particular, the component with a molecular weight interception of ≤6 kDa has a tyrosinase inhibition rate that is 39.9% higher than that of the stock solution.

[0071] Example 4

[0072] A method for preparing a concentrated peony flower liquid rich in aroma components comprises the following steps:

[0073] (1) Take fresh peony flowers, pre-cool them at -18℃ for 5 h, and then deep freeze them at -50℃ for 5 h. Take the frozen peony flowers and shear and crush them in a circulating liquid nitrogen atmosphere. The liquid nitrogen temperature in the crushing equipment cavity and pipeline is -50℃. Sieve the powder to obtain peony flower full powder with a particle size of less than 50 μm.

[0074] (2) Take the peony flower powder obtained in (1), add citric acid buffer at a material-liquid mass ratio of 1:5, and adjust the pH value of the mixed solution to 6.0. Use complex enzyme to hydrolyze at room temperature for 2 h. During the enzymatic hydrolysis, ultrasonic treatment is performed twice, each ultrasonic treatment is 0.5 h and then ultrasonic treatment is performed again after an interval of 0.5 h. The ultrasonic frequency is 40 kHz to obtain an enzymatic hydrolyzate.

[0075] In the complex enzyme, the addition amount of cellulase and neutral protease was 20 U / g and 30 U / g dry basis peony flower whole micronized powder weight, respectively;

[0076] (3) The enzymatic hydrolysate obtained in (2) was subjected to high-speed refrigerated centrifugation at a speed of 8000 rpm, a centrifugal time of 10 min, and a temperature of 4°C. The supernatant was retained and ultrafiltered using an ultrafiltration membrane to intercept and obtain components with a molecular weight of ≤6 kDa to obtain a product enrichment solution;

[0077] (4) The product enrichment solution obtained in (3) is subjected to low-temperature vacuum film concentration at an evaporation temperature of ≤50°C, and concentrated to 1 / 5 of the volume of the enrichment solution. Then, citric acid buffer is added to adjust the pH value to 5.5, sterilized at 80°C for 25 min, and filtered to obtain a peony flower concentrated stock solution rich in aroma components.

[0078] The activity of the concentrated peony flower solution rich in aroma components prepared in this example was tested, and the inhibitory effects of the concentrated peony flower solution rich in aroma components on tyrosinase activity, melanin synthesis in B16F10 cells, and TNF-α secretion in RAW264.7 cells at different concentrations were measured. The results are shown in the attached table. Figure 1-3 .

[0079] The results of the inhibition rate of tyrosinase activity of the peony flower concentrated solution rich in aroma components are shown in the attached figure. Figure 1 shown.

[0080] The data in the figure show that different concentrations of peony flower concentrates rich in aroma components all have a concentration-dependent inhibitory effect on tyrosinase activity. When the drug concentration ranges from 6.25 to 800 μg / mL, the inhibitory effect on tyrosinase is dose-dependent, increasing with increasing drug concentration. According to the fitting curve (y = -7×10 -5 x 2 +0.1007x+16.587, R 2 =0.9988) can be obtained, peony flower extract IC 50 It is 640.3μg / mL.

[0081] The inhibition of the obtained peony flower concentrated solution rich in aroma components on the melanin synthesis of B16F10 cells is shown in the attached Figure 2 shown.

[0082] The experimental results showed that when the concentration of peony flower concentrated stock solution rich in aroma components was 6.25 μg / mL, 12.5 μg / mL, 25 μg / mL, 50 μg / mL, 100 μg / mL, 200 μg / mL, 400 μg / mL, and 800 μg / mL, the inhibition rates on cell melanin synthesis were 0.79±1.32%, 2.06±1.15%, 5.32±1.78%, 13.39±1.36% (P<0.01), 25.73±1.13% (P<0.0001), 32.23±0.82% (P<0.0001), 42.33±0.95% (P<0.0001), and 52.94±1.42% (P<0.0001), respectively.

[0083] It is not difficult to see from the experimental results that the peony flower concentrated stock solution rich in aroma components obtained by the method of the present invention has an inhibitory effect on the melanin production of B16F10 cells at a certain concentration, and is concentration-dependent.

[0084] The inhibition of TNF-α secretion by the obtained peony flower concentrated solution rich in aroma components on RAW264.7 cells is shown in the attached Figure 3 shown.

[0085] The results showed that when the concentration of peony flower concentrate rich in aroma components was 6.25 μg / mL, 12.5 μg / mL, 25 μg / mL, 50 μg / mL, 100 μg / mL, 200 When the concentrations of 400 μg / mL, 800 μg / mL, the inhibition rates on TNF-α secretion of cells were 5.08±0.75%, 12.46±0.54% (P<0.001), 19.83±1.74% (P<0.001), 24.93±1.73% (P<0.001), 40.02±0.98% (P<0.0001), 46.52±0.92% (P<0.0001), 54.68±0.85% (P<0.0001), and 62.28±1.03% (P<0.0001), respectively.

[0086] The above results show that the peony flower extract rich in aroma components has an inhibitory effect on the secretion of TNF-α by RAW264.7 cells at a certain concentration, and is concentration-dependent.

[0087] Comparative Example 1

[0088] A peony flower concentrated stock solution was prepared using a supercritical fluid method. The specific experimental procedures are as follows:

[0089] Supercritical carbon dioxide fluid was used to extract peony flower stock solution: the specific operating parameters were extraction pressure 30 MPa, extraction temperature 55℃; separator I pressure 8 MPa, separator I temperature 65℃; separator II pressure 8 MPa, separator II temperature 20℃.

[0090] Comparative Example 2

[0091] A double enzyme digestion method was used to prepare a concentrated peony flower solution. The specific experimental procedures were as follows:

[0092] Peony flowers were used as raw materials, and citric acid buffer was added at a mass-to-volume ratio of 1:5. The pH value of the mixture was adjusted to 6.0. Complex enzymes were added and hydrolyzed at room temperature for 2 h. The added amounts of cellulase and neutral protease were 20 U / g and 30 U / g of dry peony flower whole micronized powder, respectively. The enzymatic hydrolyzate was sterilized at 80°C for 25 min and filtered. The product enrichment solution was concentrated by low-temperature vacuum membrane concentration at an evaporation temperature of ≤50°C to 1 / 5 of the volume of the enrichment solution to obtain peony flower concentrated stock solution.

[0093] Comparative Example 3

[0094] A peony flower concentrated liquid was prepared by conventional atmospheric distillation. The specific experimental procedures are as follows:

[0095] The peony flower raw material was boiled and refluxed with 5 times distilled water for 2 hours, allowed to stand at room temperature and then filtered. The filtrate was concentrated to 1 / 5 of the original volume at a temperature of 70-85°C to obtain a peony flower concentrated stock solution.

[0096] Comparative Example 4

[0097] A peony flower concentrated stock solution was prepared by rotary evaporation. The specific experimental operation is as follows:

[0098] Fresh peony flowers were subjected to reduced pressure distillation in a rotary evaporator, using distilled water as the extraction solvent, a solid-liquid ratio of 1:5, and reduced pressure distillation for 2 hours at a rotation speed of 60 rpm, a vacuum degree of -0.09 MPa, and a temperature of 90°C. After the reduced pressure distillation was completed, a peony flower extract was collected; the extract was subjected to low-temperature vacuum thin film concentration at an evaporation temperature of ≤50°C and concentrated to 1 / 5 of the volume of the enriched liquid to obtain a peony flower concentrated stock solution.

[0099] The components in the peony flower concentrated liquid obtained by different methods were tested, and the content of each component in the products obtained by different methods is shown in Table 5 below.

[0100] Table 5 Comparison of components of peony flower concentrated solution obtained by different methods

[0101] Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Total polyphenols / mg / g 133.87 121.98 99.54 25.23 33.78 Total flavonoids / mg / g 25.79 27.23 18.43 4.79 8.76 Linalool oxide / % 7.78 7.33 5.67 5.56 6.35 Citronellol / % 1.23 0.84 0.56 1.39 1.05 Geraniol / % 0.93 0.57 0.42 1.83 1.24 Benzoic acid / % 0.77 0.80 0.62 0.69 0.73 Vc / mg / 100g 223 163 152 37 52 Gallic acid / mg / 100g 406 379 325 232 273 Flavonoid glycosides / mg / 100g 1324 879 1024 573 732

[0102] The results in Table 5 show that the peony flower concentrated solutions prepared by different methods all contain the aforementioned active ingredients, but the content of each active ingredient varies significantly. The concentrated solution obtained by conventional atmospheric distillation has the lowest active ingredient content, likely due to the destruction of the active substances by the high temperature. The concentrated solution obtained by the method of the present invention, on the other hand, has significantly higher contents of total polyphenols, total flavonoids, and major aroma compounds (measured as linalool oxide, citronellol, geraniol, and benzoic acid) than peony flower concentrated solutions obtained by other methods.

[0103] Experimental Example 1

[0104] This experimental example focuses on verifying the effect of adding the product stability enhancer provided by the present invention. The specific experimental operation is as follows:

[0105] First, a concentrated peony flower solution rich in aroma components was obtained according to the method in Example 4. Then, a product stability enhancer was added to the obtained concentrated peony flower solution rich in aroma components, and the mixture was stirred evenly to obtain a product containing a concentrated peony flower solution rich in aroma components.

[0106] The stability enhancer used in this product is prepared by the following method:

[0107] Add 20 mL of peony seed oil, 5 g of sodium lactate, and 100 mL of water into the reaction tank, stir and heat to 70°C, then add 0.6 g of ε-polylysine hydrochloride and 3 g of methyl hydroxybenzoate, stir and then add citric acid buffer, adjust the pH to 5.5, then add 20 g of chitosan, stir evenly, and cool to room temperature.

[0108] The product containing the concentrated peony flower stock solution rich in aroma components prepared in this experimental example and the concentrated peony flower stock solution obtained by the method of Comparative Examples 1-4 were placed at room temperature for 1 month to compare the stability of the concentrated peony flower stock solution. The turbidity of the products after placement is shown in the attached figure. Figure 4 shown.

[0109] Attachment Figure 4 In the figure, a is a picture of the product prepared in Experimental Example 1; bg are pictures of different products after being placed at room temperature for 1 month, specifically: b-product of Experimental Example 1, c-product of Example 4; d-product of Comparative Example 1; e-product of Comparative Example 2; f-product of Comparative Example 3; g-product of Comparative Example 4.

[0110] From the attached Figure 4 As can be seen from Figures a and b, the product obtained by adding the product stability enhancer provided by the present invention to the prepared peony flower concentrated stock solution rich in aroma components, i.e., the product in Experimental Example 1, maintains good clarity and color after being stored at room temperature for one month. The clarity of the product without the addition of the stability enhancer is slightly reduced, as shown in Figure c. It can be seen that the addition of the product stability enhancer provided by the present invention has a good effect on maintaining product stability.

[0111] In addition, Figure dg shows that the peony flower concentrated liquid product prepared by the method of Comparative Examples 1-4 has obvious browning and a significant decrease in clarity after being placed at room temperature for one month.

[0112] Experimental Example 2-10

[0113] In order to further verify the effect of the product stability enhancer provided by the present invention, the inventors also conducted the following experiments:

[0114] The difference from Experimental Example 1 is that the composition of the stability enhancer is different. Other conditions remain unchanged. The browning degree and turbidity increase rate of the product after storage at room temperature for one month are shown in Table 6 below.

[0115] Table 6 Stability of the product after storage at room temperature for 1 month

[0116] Peony seed oil / mL Sodium lactate / g ε-Polylysine hydrochloride / g Methyl hydroxybenzoate / g Chitosan / g Browning degree increase rate / % Turbidity increase rate / % Experimental Example 2 30 4 0.5 2.5 15 0 0 Experimental Example 3 0 4 0.5 2.5 15 0.05 0.02 Experimental Example 4 50 4 0.5 2.5 15 0.08 0.17 Experimental Example 5 30 2 0.5 2.5 15 0.06 0.28 Experimental Example 6 30 6 0.5 2.5 15 0.07 0.06 Experimental Example 7 30 4 0.3 1.5 15 0.18 0.05 Experimental Example 8 30 4 0.7 3.5 15 0.01 0.10 Experimental Example 9 30 4 0.5 2.5 0 0.10 0.32 Experimental Example 10 30 4 0.5 2.5 30 0.06 0.04

[0117] Note 1: The browning degree is measured using a colorimeter. The browning degree increase rate is expressed as: (the average of three results of the liquid products of Experimental Examples 3-10 - the measured value of Experimental Example 2) / the measured value of Experimental Example 2.

[0118] Note 2: Turbidity was measured using a turbidity meter, and the turbidity increase rate was expressed as: (the average of three results of the liquid products of Experimental Examples 3-10 - the value measured in Experimental Example 2) / the value measured in Experimental Example 2.

[0119] The results in Table 6 show that the addition of the product stability enhancer provided by the present invention has a good stabilizing effect on the preservation of the peony flower liquid rich in aroma components, which is beneficial to prolonging the storage period of the peony flower liquid.

[0120] The peony flower concentrated stock solution of the present invention is rich in aroma components such as linalool oxide, citronellol, geraniol, and benzoic acid, and has a high flavonoid content. In addition, the flavonoids also contain a portion of aroma components. Therefore, the peony flower concentrated stock solution with rich aroma components can be used in the production of products such as essences and spices. For example, the concentrated stock solution can be used in the production of essences and spices as a whole, or the aroma components can be further separated and mixed with other spices to produce essences or spices with target aromas.

Claims

1. A method for preparing a concentrated peony flower solution rich in aroma components, characterized in that: The following steps are involved: (1) Take fresh peony flowers, pre-cool them at -18℃ for 5 h, and then deep freeze them at -50℃ for 5 h. Take the frozen peony flowers and shear and crush them in a circulating liquid nitrogen atmosphere. The liquid nitrogen temperature in the crushing equipment cavity and pipeline is -50℃. Sieve the powder to obtain peony flower full powder with a particle size of less than 50 μm. (2) Take the peony flower powder obtained in (1), add citric acid buffer at a material-liquid mass ratio of 1:5, and adjust the pH value of the mixed solution to 6.

0. Use complex enzyme to hydrolyze at room temperature for 2 h. During the enzymatic hydrolysis, ultrasonic treatment is performed twice, each ultrasonic treatment is performed for 0.5 h and then ultrasonic treatment is performed again after an interval of 0.5 h. The ultrasonic frequency is 40 kHz to obtain an enzymatic hydrolyzate. In the complex enzyme, the addition amount of cellulase and neutral protease is 20 U / g and 30 U / g of dry peony flower whole micropowder weight, respectively; (3) the enzymatic hydrolysate obtained in (2) is centrifuged at a speed of 8000 rpm, a centrifugal time of 10 min, and a temperature of 4°C. The supernatant is retained and ultrafiltered using an ultrafiltration membrane to intercept and obtain components with a molecular weight of ≤6 kDa, thereby obtaining a product enrichment solution; (4) The product enrichment solution obtained in (3) is subjected to low-temperature vacuum film concentration at an evaporation temperature of ≤50°C, and concentrated to 1 / 5 of the volume of the enrichment solution. Then, citric acid buffer is added to adjust the pH value to 5.5, sterilized at 80°C for 25 min, and filtered to obtain a peony flower concentrated stock solution rich in aroma components.

2. A product containing the peony flower concentrated liquid rich in aroma components as claimed in claim 1, characterized in that: The product is obtained by adding a product stability enhancer to the peony flower concentrated stock solution rich in aroma components obtained in (4) and stirring the mixture evenly, wherein 2 to 5 g of the product stability enhancer is added to every 100 mL of the peony flower concentrated stock solution rich in aroma components; the product stability enhancer is prepared by the following method: Add 20-40 mL of peony seed oil, 3-5 g of sodium lactate, and 100 mL of water into a reaction tank, stir and heat to 60-80°C, then add 0.4-0.6 g of ε-polylysine hydrochloride and 2-3 g of methyl hydroxybenzoate, stir, then add citric acid buffer, adjust the pH to 5.5-6.0, then add 10-20 g of chitosan, stir evenly, and cool to room temperature to prepare a stability enhancer.

3. Use of the peony flower concentrated liquid rich in aroma components as claimed in claim 1 or the product as claimed in claim 2 in skin care products.

4. Use of the peony flower concentrated liquid rich in aroma components as claimed in claim 1 or the product as claimed in claim 2 in flavors / spices.

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