Natural plant extract for purifying air and method of preparation

Abstract

The present application belongs to the field of air purification technology, and discloses a natural plant extract for purifying air and a preparation method. According to weight fractions, the raw material components include 40-60 parts of cypress fruit fermentation product filtrate, 5-12 parts of cedar extract, 3-8 parts of juniper seed extract, 2-7 parts of bergamot extract, 1-5 parts of sandalwood extract, 15-25 parts of ethanol, and 5-15 parts of deionized water. The mass ratio of the cypress fruit fermentation product filtrate to the cedar extract is 4:1-6:1. The product does not add artificial flavors and preservatives, and has a synergistic reducing effect on formaldehyde, toluene, ammonia and PM2.5 in a closed space when used in atomization. The present application effectively improves the retention rate of active terpenoids through an antioxidant system, realizes the synergistic purification of multiple types of air pollutants through multi-component compounding, has no artificial irritating added components, has stable batch performance, can adapt to various closed space air purification scenes, and has no secondary pollution risk.

Description

Technical Field

[0001] This invention belongs to the field of air purification technology, and in particular to a natural plant extract for purifying air and its preparation method. Background Technology

[0002] In the field of indoor air purification, long-term exposure to pollutants such as formaldehyde and toluene left over from renovations, odors and ammonia generated during daily life, as well as suspended PM2.5 and microbial aerosols in enclosed spaces such as residential homes, commercial offices, and vehicles can significantly reduce human comfort and even affect human health, leading to a continuous expansion of market demand for air purification products.

[0003] Currently, mainstream air purification technologies fall into two categories. The first category consists of chemical purification products, represented by photocatalytic sprays and chemical formaldehyde removers. These products work by directly decomposing gaseous pollutants through catalytic oxidation or neutralization reactions. Some products incorporate artificial fragrances to mask odors. These products are fast-acting and have low production costs, making them widely used in post-renovation formaldehyde removal. However, these products generally rely on synthetic chemical components, and some unreacted active components can easily cause secondary pollution. Added artificial fragrances and preservatives can irritate the respiratory mucosa, posing safety risks to the elderly, children, and people with respiratory sensitivities. Furthermore, most are only effective against single pollutants, exhibiting poor adaptability to purifying multiple types of complex pollutants.

[0004] The second category consists of plant-derived purification products, represented by formulations made from single herbal extracts. Their working principle relies on the terpenes and flavonoids naturally present in plants to adsorb and decompose pollutants, while also exerting antibacterial effects. Their safety is superior to chemical products. However, existing plant-derived products generally suffer from low levels of effective active ingredients. They are mostly prepared using ordinary extraction processes, resulting in a retention rate of less than 30% for flavonoids, polyphenols, and terpenoids. Some products prepared using fermentation processes lack antioxidant protection systems, leading to an oxidation loss rate exceeding 40% for core deodorizing and antibacterial components such as α-pinene during fermentation. Furthermore, most are single-component or simply compounded formulations, failing to utilize the synergistic effects of different plant active components. The actual comprehensive removal rate for multiple types of pollutants is far lower than the theoretical value, and they exhibit poor long-term storage stability, easily leading to decreased activity and deterioration due to stratification.

[0005] In summary, existing air purification products cannot simultaneously achieve purification efficiency, safety in use, compatibility with multiple pollutants, and storage stability, making it difficult to meet the core needs for healthy purification in current enclosed environments. Summary of the Invention

[0006] To address the shortcomings of existing air purification products, such as the tendency to leave irritating components, low retention rate of active substances, and poor adaptability to purifying various types of complex pollutants, this invention provides a natural plant extract for air purification and its preparation method.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A natural plant extract for purifying air, comprising, by weight, 40-60 parts of cypress fruit fermentation product filtrate, 5-12 parts of cedarwood extract, 3-8 parts of juniper seed extract, 2-7 parts of bergamot extract, 1-5 parts of sandalwood extract, 15-25 parts of ethanol, and 5-15 parts of deionized water. The mass ratio of the cypress fruit fermentation product filtrate to the cedar extract is 4:1 to 6:1; the natural plant extract contains no artificial fragrances or preservatives, and when used in atomization, it has a synergistic effect in reducing formaldehyde, toluene, ammonia, and PM2.5 in enclosed spaces.

[0008] Furthermore, the filtrate of the cypress fruit fermentation product is obtained by fermenting cypress fruit with a combination of brewer's yeast and Lactobacillus plantarum. The total flavonoid content in the fermentation product is not less than 12 mg / g, and the total polyphenol content is not less than 8 mg / g. During the fermentation process, 0.1% to 0.5% of vitamin C is added as an antioxidant, which increases the α-pinene content in the fermentation broth by more than 30% compared with the group without added vitamin C.

[0009] Furthermore, the cedar extract, juniper seed extract, bergamot extract, and sandalwood extract are all fat-soluble active extracts prepared by supercritical CO2 extraction, and the total content of terpenoid active substances in the extracts is not less than 30%.

[0010] Furthermore, the pH value of the natural plant extract is 5.5~6.5, which is close to the pH value of human skin surface; the natural plant extract is non-irritating to mucous membranes; the total bacterial count is <10 CFU / mL, mold and yeast are <10 CFU / mL, and pathogenic bacteria were not detected; mercury is <0.002 mg / kg, lead is <1.5 mg / kg, arsenic is <0.01 mg / kg, and cadmium is <0.18 mg / kg.

[0011] Furthermore, under simulated indoor environmental conditions of 20-30°C and 40-60% relative humidity, the removal rate of formaldehyde, toluene, ammonia, and PM2.5 by the natural plant extract is at least 5 percentage points higher than the theoretical sum value.

[0012] Furthermore, the following steps are included: S1. Preparation of filtrate from fermentation of cypress fruit: Fresh cypress fruit harvested in the current season is taken, and after removing impurities, washing with purified water, and naturally drying until the moisture content is less than 15%, it is pulverized to 40-80 mesh using a low-temperature pulverizer to obtain cypress fruit powder; the cypress fruit powder is mixed with deionized water at a mass ratio of 1:5 to 1:10, and sterilized at 121℃ for 15-20 minutes, then cooled to room temperature; a compound inoculum of brewer's yeast and Lactobacillus plantarum is inoculated, wherein the ratio of live bacteria of brewer's yeast to Lactobacillus plantarum in the compound inoculum is 1:1 to 1:3, and the inoculation amount is 1% to 3% of the total mass of the fermentation system; at the same time, 0.1% to 0.5% of vitamin C is added to the total mass of the fermentation system; Fermentation was carried out under anaerobic conditions at 25-35℃ for 7-15 days. During the fermentation process, aeration and stirring were performed every 2 days at a speed of 50-100 r / min for 5-10 minutes each time. After the fermentation was completed, the fermentation was considered to have ended when the pH of the fermentation broth dropped to 3.0-4.5 and the total flavonoid content was ≥12 mg / g. The residue was first removed by coarse filtration through a 200-mesh filter cloth, and then centrifuged at 4000-6000 r / min for 10-20 minutes. The supernatant was then autoclaved at 121℃ for 15-20 minutes and cooled to room temperature to obtain the cypress fruit fermentation product filtrate. S2. Preparation of Single-Flavor Plant Extracts: Young cedar branches, mature juniper seeds, fresh bergamot fruit, and sandalwood shavings from trees over five years old were selected as raw materials. After impurity removal, washing with purified water, and natural drying until the moisture content was below 15%, each raw material powder was pulverized to 40-80 mesh using a low-temperature pulverizer. The powders were then used to prepare corresponding extracts via supercritical CO2 extraction. The extraction pressure was set to 20-30 MPa, the extraction temperature to 35-45℃, the CO2 flow rate to 15-25 L / h, and the extraction time to 1-3 hours. During extraction, 5%-10% ethanol (by weight of the raw material powder) was added as an entrainer to increase the total extraction rate of terpenoids by at least 15% compared to extraction without an entrainer. After extraction, the corresponding single-flavor plant extracts were obtained and prepared for use. S3. Mixing, blending and filling: Add the cypress fruit fermentation product filtrate prepared in S1, the single plant extracts prepared in S2, food-grade ethanol and deionized water to a mixing tank according to the weight ratio, so that the mass ratio of cypress fruit fermentation product filtrate to cedar extract is 4:1~6:1; stir at a constant temperature of 30~40℃ and a speed of 150~250r / min for 20~40 minutes; after stirring evenly, let stand for 12~24 hours, take the clear liquid from the top layer and filter it through a 0.22μm microporous membrane for sterilization, and then aseptically fill it to obtain the finished natural plant extract product.

[0013] Furthermore, the amount of vitamin C added in step S1 is 0.2% to 0.3% of the total mass of the fermentation system, and the dissolved oxygen content is controlled to not exceed 0.5 mg / L during the fermentation process, so that the α-pinene content in the fermentation broth is increased by more than 30% compared with the group without vitamin C; and after verification by at least 3 batches of pilot production, the batch-to-batch relative standard deviation of α-pinene content is ≤10%.

[0014] Furthermore, when ethanol is used as an entrainer in step S2, its addition amount is 6%~8% of the raw material powder mass, the supercritical CO2 extraction pressure is 23~27MPa, and the extraction temperature is 38~42℃, so that the content of sesquiterpenoid compounds in sandalwood extract is increased to more than 20%.

[0015] Furthermore, the settling temperature in step S3 is 20~25℃, and the settling process is conducted in the dark and without vibration.

[0016] The present invention has the following beneficial effects: This invention uses a blend of active ingredients from multiple natural plants, without adding any artificial fragrances or preservatives throughout the process. It also strictly controls the product's microbial and heavy metal safety indicators and adjusts the product's pH to match the pH of human skin, achieving a non-irritating effect on the mucous membrane and without secondary pollutant residues. This effectively solves the problems of existing chemical purification products that easily leave irritating components and generate secondary pollution, as well as the shortcomings of ordinary plant-based purification products that are prone to microbial growth and have poor storage stability.

[0017] This invention adds an antioxidant during the fermentation of cypress fruit, combined with an anaerobic fermentation process featuring low-frequency micro-aeration, and employs a supercritical CO2 extraction process with an entrainer to prepare single-herb plant extracts. This significantly improves the retention rate of core active substances, effectively solving the defects of high oxidation loss rate of active components and low total active substance content in the preparation of existing plant-derived purification products, and providing core support for the purification efficiency of the product.

[0018] This invention achieves a synergistic purification effect among the plant active components by regulating the ratio of cypress fruit fermentation product filtrate to cedarwood extract within a specific range. This significantly improves the overall removal efficiency of various common indoor gaseous pollutants and suspended particulate matter compared to the theoretical summation of individual components, effectively addressing the shortcomings of existing purification products that only target single pollutants and have poor adaptability to complex pollution scenarios. This product can be directly atomized and is compatible with various atomization terminals such as aroma diffusers, car atomizers, and public space spray systems. It can be widely used in various scenarios including residential homes, commercial offices, vehicles, and enclosed public venues. It exhibits strong adaptability to different temperature and humidity environments, requires no additional professional operating equipment, and possesses high industry promotion value. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the preparation process of a natural plant extract for purifying air, as proposed in this invention. Figure 2 This is a line graph showing the change in α-pinene retention rate throughout the entire fermentation cycle proposed in this invention. Figure 3 This is a bar chart showing the relationship between dissolved oxygen content and α-pinene retention rate in the fermentation system proposed in this invention. Figure 4 Radar graphs showing the removal effects of composite pollutants on different samples proposed in this invention; Figure 5 This is a bar chart showing the relative standard deviation of α-pinene retention rates in different pilot batches of samples proposed in this invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0021] Example 1

[0022] The natural plant extract for purifying air described in this embodiment comprises, by weight, 50 parts of cypress fruit fermentation product filtrate, 10 parts of cedar extract, 5 parts of juniper seed extract, 4 parts of bergamot extract, 3 parts of sandalwood extract, 20 parts of food-grade ethanol, and 8 parts of deionized water, wherein the mass ratio of cypress fruit fermentation product filtrate to cedar extract is 5:1.

[0023] This product contains no artificial fragrances or preservatives. When used in atomized formaldehyde, toluene, ammonia, and PM2.5 concentrations in enclosed spaces, the components work synergistically as follows: Cypress fruit fermentation filtrate, rich in flavonoids and polyphenols, catalyzes the decomposition of polar gaseous pollutants such as formaldehyde and ammonia; cedarwood extract, rich in α-pinene terpenes, decomposes non-polar pollutants such as toluene while inhibiting microbial growth; the porous terpenoid components of juniper seed extract adsorb suspended PM2.5; the limonene component of bergamot extract neutralizes odor molecules; the sesquiterpenes of sandalwood extract prolong the duration of the active ingredients' effectiveness; ethanol acts as a co-solvent to enhance the miscibility of the components; and deionized water serves as a carrier suitable for atomized use.

[0024] The preparation steps in this embodiment are as follows: S1. Preparation of filtrate from fermentation of cypress fruit: Freshly harvested cypress fruit was removed, rinsed three times with purified water, and naturally sun-dried until the moisture content reached 12%. The powder was then pulverized to 60 mesh using a low-temperature pulverizer to obtain cypress fruit powder. The cypress fruit powder was mixed with deionized water at a mass ratio of 1:8, and sterilized at 121℃ for 18 minutes under high pressure, then cooled to room temperature. A compound inoculum of *Saccharomyces cerevisiae* and *Lactobacillus plantarum* was inoculated, with a live bacteria ratio of 1:2, at an inoculation amount of 2% of the total fermentation system mass. Simultaneously, 0.25% of vitamin C was added as an antioxidant.

[0025] Fermentation was carried out at 30℃, with the dissolved oxygen level in the fermentation system controlled at 0.3 mg / L throughout the process. Aeration and stirring were performed every two days at a speed of 80 rpm for 8 minutes each time. After 10 days of fermentation, the pH of the fermentation broth dropped to 3.8, and the total flavonoid content was measured to be 13.2 mg / g and the total polyphenol content to be 9.1 mg / g, indicating that the fermentation had reached its endpoint.

[0026] First, the residue was removed by coarse filtration through a 200-mesh filter cloth. Then, the mixture was centrifuged at 5000 rpm for 15 minutes. The supernatant was then autoclaved at 121℃ for 18 minutes and cooled to room temperature to obtain the cypress fruit fermentation product filtrate. In this step, the α-pinene content was increased by more than 30% compared to the group without vitamin C, which clearly indicates that the α-pinene retention rate was 30 percentage points higher than the control group without vitamin C. In this example, the α-pinene retention rate was measured to be 82%, while the retention rate in the control group without vitamin C was 48%, representing an increase of 34 percentage points.

[0027] Three consecutive batches of pilot-scale production verification were conducted, and the α-pinene retention rates were measured to be 81.8%, 82.3%, and 81.9%, respectively, with a batch-to-batch relative standard deviation of 0.25%. If the dissolved oxygen level exceeds 0.5 mg / L, even with the addition of an equal amount of vitamin C, the α-pinene oxidation rate will still increase by more than two times, and the retention rate will be less than 60% after 10 days of fermentation, failing to meet the requirements for improved retention.

[0028] S2. Preparation of Single-Flavor Plant Extracts: Three-year-old cedar twigs, mature juniper seeds, fresh bergamot fruit, and five-year-old or older sandalwood shavings were selected as raw materials. After impurity removal, rinsing three times with purified water, and natural drying until the moisture content was 12%, each raw material was pulverized to 60 mesh using a low-temperature pulverizer to obtain powders. The powders were then used to prepare corresponding extracts using supercritical CO2 extraction. The extraction pressure was set to 25 MPa, the extraction temperature to 40℃, the CO2 flow rate to 20 L / h, and the extraction time to 2 hours. During extraction, 7% (by weight of the raw material powder) of food-grade ethanol was added as an entrainer. The total terpenoid content of the cedar extract was 36%, that of the juniper seed extract was 33%, that of the bergamot extract was 31%, and that of the sandalwood extract was 32%, of which the content of sesquiterpenoids in the sandalwood extract was 23%.

[0029] S3. Mixing, Blending, and Filling: The filtrate of the cypress fruit fermentation product prepared in S1, the individual plant extracts prepared in S2, food-grade ethanol, and deionized water are added to a stainless steel mixing tank according to the weight ratio. The mixture is stirred at 200 rpm for 30 minutes at a constant temperature of 35°C. After thorough mixing, it is transferred to a light-proof settling tank and settling at 22°C under light-proof and vibration-free conditions for 18 hours. The clear supernatant is then filtered through a 0.22 μm microporous membrane for sterilization and aseptically filled to obtain the finished natural plant extract product.

[0030] The pH value of the finished product in this embodiment was measured to be 6.1, which is compatible with the pH value of human skin surface; the finished product was tested and found to be non-irritating to rabbit eye mucous membranes; the microbial indicators were: total bacterial count 3 CFU / mL, mold and yeast <10 CFU / mL, and no pathogenic bacteria were detected; the heavy metal indicators were: mercury 0.001 mg / kg, lead 0.8 mg / kg, arsenic 0.005 mg / kg, and cadmium 0.11 mg / kg, which met the safety requirements.

[0031] The synergistic purification effect test in this embodiment strictly followed the following reproducible conditions: a 30m... 3 The standard test chamber was used, with a test environment of 25℃ and 50% relative humidity, which meets the conditions for simulating an indoor environment; the initial concentration of each pollutant was 1.0 mg / m³ for formaldehyde. 3 Toluene 1.5 mg / m 3 Ammonia 0.5 mg / m³ 3 PM2.5 300μg / m 3 The sample volume was 20 mL, and it was atomized for 10 minutes using an ultrasonic nebulizer with a power of 30 W. After 24 hours, the residual concentration of each pollutant was tested according to the GB / T 18801-2022 standard "Air Purifier".

[0032] The theoretical summation value is calculated as follows: Theoretical summation removal rate of a single pollutant = Σ (Individual removal rate of the pollutant by a single ingredient × Mass percentage of the ingredient in the finished product), where the individual removal rate of a single ingredient is the removal rate measured using an equal mass of a single ingredient under the same test conditions. In this embodiment, the measured formaldehyde removal rate was 92%, toluene removal rate was 88%, ammonia removal rate was 90%, and PM2.5 removal rate was 85%, corresponding to theoretical summation values ​​of 85%, 81%, 82%, and 77%, respectively. The measured values ​​are 7, 7, 8, and 8 percentage points higher than the theoretical summation values, respectively.

[0033] Example 2

[0034] The natural plant extract for purifying air described in this embodiment comprises, by weight, 40 parts of cypress fruit fermentation product filtrate, 10 parts of cedar extract, 3 parts of juniper seed extract, 2 parts of bergamot extract, 1 part of sandalwood extract, 25 parts of food-grade ethanol, and 9 parts of deionized water, wherein the mass ratio of cypress fruit fermentation product filtrate to cedar extract is 4:1.

[0035] The preparation steps in this embodiment are as follows: S1. Preparation of filtrate from fermentation of cypress fruit: Freshly harvested cypress fruit was removed, rinsed three times with purified water, and naturally sun-dried until the moisture content reached 14%. The powder was then pulverized to 40 mesh using a low-temperature pulverizer to obtain cypress fruit powder. The cypress fruit powder was mixed with deionized water at a mass ratio of 1:5, and sterilized at 121℃ for 15 minutes under high pressure, then cooled to room temperature. A compound inoculum of *Saccharomyces cerevisiae* and *Lactobacillus plantarum* was inoculated, with a live bacteria ratio of 1:1 and an inoculation amount of 1% of the total mass of the fermentation system. Simultaneously, 0.1% of vitamin C was added as an antioxidant.

[0036] Fermentation was carried out at 25℃, with the dissolved oxygen level in the fermentation system controlled at 0.45 mg / L throughout the process. Aeration and stirring were performed every two days at a speed of 50 rpm for 5 minutes each time. After 7 days of fermentation, the pH of the fermentation broth dropped to 4.3, and the total flavonoid content was measured to be 12.1 mg / g and the total polyphenol content to be 8.3 mg / g, indicating that the fermentation had reached its endpoint.

[0037] First, the filter residue was removed by coarse filtration using a 200-mesh filter cloth. Then, the mixture was centrifuged at 4000 r / min for 10 minutes. The supernatant was then sterilized at 121℃ for 15 minutes and cooled to room temperature to obtain the filtrate of cypress fruit fermentation product.

[0038] In this embodiment, the α-pinene retention rate was measured to be 79%, compared to 47% in the control group without vitamin C, representing an improvement of 32 percentage points. Three consecutive batches of pilot-scale production were conducted for verification, yielding α-pinene retention rates of 78.7%, 79.2%, and 79.1%, respectively, with a batch-to-batch relative standard deviation of 0.33%.

[0039] S2. Preparation of Single-Flavor Plant Extracts: Three-year-old cedar twigs, mature juniper seeds, fresh bergamot fruit, and five-year-old or older sandalwood shavings were selected as raw materials. After impurity removal, rinsing three times with purified water, and natural drying until the moisture content was 14%, each raw material was pulverized to 40 mesh using a low-temperature pulverizer to obtain powders. The powders were then used to prepare corresponding extracts using supercritical CO2 extraction. The extraction pressure was set to 20 MPa, the extraction temperature to 35℃, the CO2 flow rate to 15 L / h, and the extraction time to 1 hour. During extraction, 5% of the raw material powder mass of food-grade ethanol was added as an entrainer. The total terpenoid content of the cedar extract was 32%, that of the juniper seed extract was 31%, that of the bergamot extract was 30%, and that of the sandalwood extract was 30%, of which the content of sesquiterpenoids in the sandalwood extract was 21%.

[0040] S3. Mixing, Blending, and Filling: The filtrate of the cypress fruit fermentation product prepared in S1, the individual plant extracts prepared in S2, food-grade ethanol, and deionized water are added to a stainless steel mixing tank according to the weight ratio. The mixture is stirred at 150 rpm for 40 minutes at a constant temperature of 30°C. After thorough mixing, it is transferred to a light-proof settling tank and settling at 20°C under light-proof and vibration-free conditions for 24 hours. The clear supernatant is then filtered through a 0.22 μm microporous membrane for sterilization and aseptically filled to obtain the finished natural plant extract product.

[0041] The pH value of the finished product in this embodiment was measured to be 5.5, which is compatible with the pH value of human skin surface; the finished product was tested and found to be non-irritating to rabbit eye mucous membranes; the microbial indicators were: total bacterial count 5 CFU / mL, mold and yeast <10 CFU / mL, and no pathogenic bacteria were detected; the heavy metal indicators were: mercury 0.001 mg / kg, lead 1.1 mg / kg, arsenic 0.007 mg / kg, and cadmium 0.15 mg / kg, which met the safety requirements.

[0042] The test conditions for the synergistic purification effect in this embodiment are the same as those in Example 1. The measured formaldehyde removal rate is 88%, toluene removal rate is 84%, ammonia removal rate is 86%, and PM2.5 removal rate is 81%, which correspond to theoretical sum values ​​of 82%, 78%, 79%, and 74%, respectively. The measured values ​​are 6, 6, 7, and 7 percentage points higher than the theoretical sum values, respectively.

[0043] Example 3

[0044] The natural plant extract for purifying air described in this embodiment comprises, by weight, 60 parts of cypress fruit fermentation product filtrate, 10 parts of cedar extract, 8 parts of juniper seed extract, 7 parts of bergamot extract, 5 parts of sandalwood extract, 15 parts of food-grade ethanol, and 5 parts of deionized water, wherein the mass ratio of cypress fruit fermentation product filtrate to cedar extract is 6:1.

[0045] The preparation steps in this embodiment are as follows: S1. Preparation of filtrate from cypress fruit fermentation products: Fresh cypress fruits harvested in the current season are taken, purified, rinsed three times with purified water, and naturally sun-dried until the moisture content is 13%. The filtrate is then pulverized to 80 mesh using a low-temperature pulverizer to obtain cypress fruit powder. The cypress fruit powder is mixed with deionized water at a mass ratio of 1:10, and sterilized at 121℃ for 20 minutes under high pressure, then cooled to room temperature. A compound inoculum of *Saccharomyces cerevisiae* and *Lactobacillus plantarum* is inoculated, with a live bacteria ratio of 1:3, at an inoculation amount of 3% of the total mass of the fermentation system. Simultaneously, 0.5% of vitamin C is added as an antioxidant.

[0046] Fermentation was carried out at 35℃, with the dissolved oxygen level controlled at 0.2 mg / L throughout the process. Aeration and stirring were performed every two days at a speed of 100 rpm for 10 minutes each time. After 15 days of fermentation, the pH of the fermentation broth dropped to 3.1, and the total flavonoid content was measured to be 14.5 mg / g and the total polyphenol content to be 10.2 mg / g, reaching the fermentation endpoint. The mixture was first coarsely filtered through a 200-mesh filter cloth to remove the filter residue, then centrifuged at 6000 rpm for 20 minutes. The supernatant was then autoclaved at 121℃ for 20 minutes and cooled to room temperature to obtain the cypress fruit fermentation product filtrate.

[0047] In this embodiment, the α-pinene retention rate was measured to be 84%, compared to 49% in the control group without vitamin C, representing an improvement of 35 percentage points. Three consecutive batches of pilot-scale production were conducted for verification, yielding α-pinene retention rates of 83.8%, 84.1%, and 84.2%, respectively, with a batch-to-batch relative standard deviation of 0.24%.

[0048] S2. Preparation of single plant extracts: Three-year-old cedar twigs, mature juniper seeds, fresh bergamot fruit, and sandalwood shavings from five years or older were selected as raw materials. After removing impurities, rinsing with purified water three times, and naturally drying to a moisture content of 13%, the raw materials were pulverized to 80 mesh using a low-temperature pulverizer to obtain powders of each raw material.

[0049] Extracts were prepared from each raw material powder using supercritical CO2 extraction. The extraction pressure was set at 30 MPa, the extraction temperature at 45℃, the CO2 flow rate at 25 L / h, and the extraction time at 3 hours. Food-grade ethanol, accounting for 10% of the raw material powder mass, was added as an entrainer during extraction. The total terpene content of the cedar extract was 38%, that of the juniper seed extract was 35%, that of the bergamot extract was 34%, and that of the sandalwood extract was 35%. Among these, the sesquiterpene compound content in the sandalwood extract was 26%.

[0050] S3. Mixing, Blending, and Filling: The filtrate of the cypress fruit fermentation product prepared in S1, the individual plant extracts prepared in S2, food-grade ethanol, and deionized water are added to a stainless steel mixing tank according to the weight ratio. The mixture is stirred at 250 rpm for 20 minutes at a constant temperature of 40℃. After thorough mixing, it is transferred to a light-proof settling tank and settling at 25℃ under light-proof and vibration-free conditions for 12 hours. The clear supernatant is then filtered through a 0.22 μm microporous membrane for sterilization and aseptically filled to obtain the finished natural plant extract product.

[0051] The pH value of the finished product in this embodiment was measured to be 6.5, which is compatible with the pH value of human skin surface; the finished product was tested and found to be non-irritating to rabbit eye mucous membranes; the microbial indicators were: total bacterial count 2 CFU / mL, mold and yeast <10 CFU / mL, and no pathogenic bacteria detected; the heavy metal indicators were: mercury 0.001 mg / kg, lead 0.7 mg / kg, arsenic 0.004 mg / kg, and cadmium 0.09 mg / kg.

[0052] The test conditions for the synergistic purification effect in this embodiment are the same as those in Example 1. The measured formaldehyde removal rate is 93%, toluene removal rate is 89%, ammonia removal rate is 91%, and PM2.5 removal rate is 86%, which correspond to theoretical sum values ​​of 86%, 82%, 83%, and 78%, respectively. The measured values ​​are 7, 7, 8, and 8 percentage points higher than the theoretical sum values, respectively.

[0053] Comparative Example 1 This comparative example used the same raw material ratio and preparation steps as Example 1, except that vitamin C was not added during the fermentation stage of the cypress fruit, and the dissolved oxygen level in the fermentation system was not controlled. The highest dissolved oxygen level measured during the fermentation process was 2.1 mg / L. After 10 days of fermentation, the total flavonoid content was 9.2 mg / g, the total polyphenol content was 6.1 mg / g, and the α-pinene retention rate was 48%, which was 34 percentage points lower than that of Example 1. The measured formaldehyde removal rate of the finished product was 76%, the toluene removal rate was 71%, the ammonia removal rate was 72%, and the PM2.5 removal rate was 65%, corresponding to theoretical summation values ​​of 75%, 70%, 71%, and 64%, respectively. The measured values ​​were only 1 percentage point higher than the theoretical summation values, indicating no significant synergistic effect.

[0054] Comparative Example 2 This comparative example uses the same preparation steps as Example 1, only adjusting the raw material ratio to 30 parts of cypress fruit fermentation product filtrate and 10 parts of cedarwood extract, with a mass ratio of 3:1. The actual formaldehyde removal rate was 83%, toluene removal rate was 78%, ammonia removal rate was 79%, and PM2.5 removal rate was 74%, corresponding to theoretical summative values ​​of 81%, 77%, 77%, and 72%, respectively. The actual values ​​were only 2 percentage points higher than the theoretical summative values, indicating no significant synergistic effect.

[0055] Data Tables and Explanations Table 1. Comparison of α-pinene retention rates at different fermentation times

[0056] This table compares the α-pinene retention rates of Example 1 and Comparative Example 1 (without added antioxidants and without controlled dissolved oxygen) throughout the entire fermentation cycle. The difference in retention rates at the end of fermentation reached 34 percentage points, verifying the synergistic effect of vitamin C's antioxidant protection and dissolved oxygen control (≤0.5 mg / L). This effectively solves the defect of high oxidation loss rate of active components, and the data shows good parallelism and reproducibility.

[0057] Table 2 Comparison of pollutant removal effects between each embodiment and the comparative example

[0058] All tests in this table strictly follow the GB / T 18801-2022 standard, at 30m. 3 The test was conducted in a standard test chamber under a simulated indoor environment with a temperature of 25°C and a relative humidity of 50%. The measured removal rates of the four types of pollutants in the three examples were all more than 5 percentage points higher than the theoretical sum value, which verified the existence of the synergistic purification effect between components and effectively solved the defect of poor adaptability of existing products to complex pollution. The test process is reproducible.

[0059] refer to Figure 2 This figure visually demonstrates the effect of the antioxidant protection system on the retention of active components during fermentation. At the end of fermentation, the α-pinene retention rate of Example 1 was 34 percentage points higher than that of Comparative Example 1, which verifies the synergistic antioxidant effect of vitamin C and low dissolved oxygen control. The data are consistent with the experimental results of the examples and comparative examples, and can accurately support the closed-loop logic of the antioxidant mechanism.

[0060] refer to Figure 3 In this figure, when the dissolved oxygen level is at or below 0.5 mg / L, the α-pinene retention rate can be maintained above 76%, which is more than 30 percentage points higher than the control group without antioxidants. Once the dissolved oxygen level exceeds 0.5 mg / L, the α-pinene retention rate drops significantly, and the retention rate is only 48% when the dissolved oxygen level is 2.0 mg / L, which cannot meet the requirements for the retention of active components. The data are repeatable, which fully proves that the dissolved oxygen threshold is the core necessary parameter to ensure the antioxidant effect and is not arbitrary.

[0061] refer to Figure 4 This diagram is based on the GB / T 18801-2022 standard, 30m. 3 Reproducible test conditions for the standard test chamber: The coverage area of ​​Example 1 is much larger than that of the two comparative examples, and the removal rates of the four types of pollutants are all more than 5 percentage points higher than the theoretical sum value. In contrast, the comparative examples that did not use the component ratio of the present invention and the antioxidant system did not have a significant synergistic effect. The test process can be reproduced by those skilled in the art.

[0062] refer to Figure 5 This figure verifies the industrial production stability of the technical solution of this invention. The batch-to-batch relative standard deviations of the three embodiments are all far below the 10% threshold, with the highest being only 0.33%, indicating extremely strong process stability and negligible batch-to-batch differences. In contrast, the batch deviations of the comparative examples that did not use the antioxidant system and component ratios of this invention all exceeded 8%, with comparative example 1 even exceeding 12%, failing to guarantee product performance uniformity. The data in this figure directly supports the feasibility of industrial implementation of this technical solution, solving the defect of large batch performance fluctuations in existing plant-derived purification products.

[0063] 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 natural plant extract for purifying air, characterized in that, By weight, the raw material components include: 40-60 parts of cypress fruit fermentation product filtrate, 5-12 parts of cedar extract, 3-8 parts of juniper seed extract, 2-7 parts of bergamot extract, 1-5 parts of sandalwood extract, 15-25 parts of ethanol, and 5-15 parts of deionized water. The mass ratio of the cypress fruit fermentation product filtrate to the cedar extract is 4:1 to 6:1; the natural plant extract contains no artificial flavors or preservatives.

2. The natural plant extract for purifying air according to claim 1, characterized in that, The filtrate of the cypress fruit fermentation product is obtained by fermenting cypress fruit with a combination of brewer's yeast and Lactobacillus plantarum. The total flavonoid content in the fermentation product is not less than 12 mg / g, and the total polyphenol content is not less than 8 mg / g. During the fermentation process, 0.1% to 0.5% vitamin C is added as an antioxidant.

3. The natural plant extract for purifying air according to claim 1, characterized in that, The cedarwood extract, juniper seed extract, bergamot extract, and sandalwood extract are all fat-soluble active extracts prepared by supercritical CO2 extraction, and the total content of terpenoid active substances in the extracts is not less than 30%.

4. The natural plant extract for purifying air according to claim 1, characterized in that, The pH value of the natural plant extract is 5.5~6.5; the natural plant extract is non-irritating to mucous membranes; the total bacterial count is <10 CFU / mL, the mold and yeast count is <10 CFU / mL, and pathogenic bacteria are not detected; mercury is <0.002 mg / kg, lead is <1.5 mg / kg, arsenic is <0.01 mg / kg, and cadmium is <0.18 mg / kg.

5. The natural plant extract for purifying air according to claim 1, characterized in that, The natural plant extracts, under simulated indoor environmental conditions of 20-30°C and 40-60% relative humidity, showed a removal rate of formaldehyde, toluene, ammonia, and PM2.5 that was at least 5 percentage points higher than the theoretical summation.

6. A method for preparing a natural plant extract for purifying air, used to prepare the natural plant extract for purifying air as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Preparation of filtrate from fermentation of cypress fruit: Fresh cypress fruit harvested in the current season is taken, and after removing impurities, washing with purified water, and naturally drying until the moisture content is less than 15%, it is pulverized to 40-80 mesh using a low-temperature pulverizer to obtain cypress fruit powder; the cypress fruit powder is mixed with deionized water at a mass ratio of 1:5 to 1:10, and sterilized at 121℃ for 15-20 minutes, then cooled to room temperature; a compound inoculum of brewer's yeast and Lactobacillus plantarum is inoculated, wherein the ratio of live bacteria of brewer's yeast to Lactobacillus plantarum in the compound inoculum is 1:1 to 1:3, and the inoculation amount is 1% to 3% of the total mass of the fermentation system; at the same time, 0.1% to 0.5% of vitamin C is added to the total mass of the fermentation system; Fermentation was carried out under anaerobic conditions at 25-35℃ for 7-15 days. During the fermentation process, aeration and stirring were performed every 2 days at a speed of 50-100 r / min for 5-10 minutes each time. After the fermentation was completed, the fermentation was considered to have ended when the pH of the fermentation broth dropped to 3.0-4.5 and the total flavonoid content was ≥12 mg / g. The residue was first removed by coarse filtration through a 200-mesh filter cloth, and then centrifuged at 4000-6000 r / min for 10-20 minutes. The supernatant was then autoclaved at 121℃ for 15-20 minutes and cooled to room temperature to obtain the cypress fruit fermentation product filtrate. S2. Preparation of single plant extracts: Select cedar twigs, mature juniper seeds, fresh bergamot fruit, and sandalwood chips from trees over five years old as raw materials. After removing impurities, washing with purified water, and naturally drying until the moisture content is less than 15%, each raw material is pulverized to 40-80 mesh using a low-temperature pulverizer to obtain powder of each raw material. Extracts were prepared from each raw material powder using supercritical CO2 extraction. The extraction pressure was set to 20-30 MPa, the extraction temperature to 35-45℃, the CO2 flow rate to 15-25 L / h, and the extraction time to 1-3 hours. Ethanol, accounting for 5%-10% of the mass of the raw material powder, was added as an entrainer during extraction. After extraction, the corresponding single-herb plant extracts were obtained by analysis and set aside for later use. S3. Mixing and filling: Add the cypress fruit fermentation product filtrate prepared in S1, the single plant extracts prepared in S2, food-grade ethanol, and deionized water to the mixing tank according to the weight ratio, so that the mass ratio of cypress fruit fermentation product filtrate to cedar extract is 4:1 to 6:

1. Stir at a constant temperature of 30-40℃ for 20-40 minutes at a speed of 150-250 r / min; after stirring evenly, let stand for 12-24 hours, take the clear liquid from the top layer and filter it through a 0.22μm microporous membrane for sterilization, and then aseptically fill it to obtain the finished natural plant extract.

7. The preparation method according to claim 6, characterized in that, The amount of vitamin C added in step S1 is 0.2% to 0.3% of the total mass of the fermentation system, and the dissolved oxygen content is controlled not to exceed 0.5 mg / L during the fermentation process; after verification by at least 3 batches of pilot production, the batch-to-batch relative standard deviation of α-pinene content is ≤10%.

8. The preparation method according to claim 6, characterized in that, When ethanol is used as an entrainer in step S2, its addition amount is 6%~8% of the mass of the raw material powder, the supercritical CO2 extraction pressure is 23~27MPa, and the extraction temperature is 38~42℃.

9. The preparation method according to claim 6, characterized in that, The settling temperature in step S3 is 20~25℃, and the settling process should be kept away from light and vibration throughout.

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