Extraction method and preservation method of vetiver root essential oil and hydrolat

Abstract

The invention discloses a vetiver root essential oil and hydrolat extraction method and a vetiver root essential oil and hydrolat preservation method.The extraction method comprises the steps of raw material pretreatment, weighing, feed liquid mixing, microwave treatment, steam distillation and essential oil and hydrolat separation treatment.By optimizing raw material pretreatment, vetiver powder particle size distribution is controlled to be uniform; the utilization rate of raw materials and the extraction efficiency of essential oil and hydrolat are effectively improved, the influence of particle size nonuniformity on the extraction efficiency of essential oil and hydrolat is avoided, a microwave mode is adopted for assisting a steam distillation method, moisture in raw material plant tissue can be rapidly heated and gasified through the heat effect of microwaves, and therefore the raw material plant matrix structure tissue is loosened and expanded, and the extraction efficiency of essential oil and hydrolat is improved. The mass transfer resistance in the extraction process is reduced, the extraction rate of vetiver essential oil and hydrolat is remarkably increased, the content of vetiver net in the essential oil is also increased, and the fragrance of the vetiver oil is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of plant essential oil and hydrolat extraction, and particularly relates to a method for extracting essential oil and hydrolat from vetiver roots. BACKGROUND

[0002] Vetiver (Chrysopogon zizanioides (L.) Roberty, formerly known as Vetiveria zizanioides) is also known as vetiver and sandal grass. Its root oil and root extract (commonly known as essential oil and hydrolat, respectively) have been included in the 2025 "List of Raw Materials for Marketed Products". At present, more than 300 compounds have been isolated from vetiver, including alcohols, hydrocarbons, ketones, aldehydes, esters, acids and ethers, most of which are terpenes, more than 150 of which are sesquiterpenes. Alcohols are the main components in vetiver essential oil, accounting for about 18% to 49% of the content of essential oil, with an average content of 41.2%. The content of hydrocarbon compounds is only slightly lower than that of alcohols, accounting for 17% to 28% of the total. Ketone compounds account for 9% to 14% of vetiver essential oil, although the proportion is not high, but they have an important contribution to the odor of vetiver volatile oil. The content of esters in vetiver essential oil varies in different regions, and in most cases, it is obtained by degradation of other substances. The acid value of vetiver essential oil is greatly related to its origin, and the content of acid substances in vetiver produced in different regions is different. Its essential oil contains more than 300 chemical components, which are a variety of volatile components, most of which are sesquiterpenes and their oxygen derivatives; and hydrolat is a condensate solution obtained by distillation of vetiver root system, which is a byproduct of sandalwood oil. It is a 100% saturated extract original liquid separated during the process of refining sandalwood oil, which contains a small amount of sandalwood oil components and all water-soluble substances in vetiver roots (such as tannins and flavonoids) in addition to the extract original liquid. The compounds obtained by different extraction methods in different planting areas are significantly different. The characteristic components in essential oil are, for example, 9,10-dehydro-isolongifolene, which has a woody aroma characteristic; gamma-cedrene, which has a sedative effect; longifolene, a tricyclic sesquiterpene, which accounts for about 60% to 78% in masson pine heavy pine oil; valencene, which is a citrus-like sesquiterpene compound; and iso-longifolane, which has a natural mosla-like woody and earthy aroma. Representative and characteristic components include B-vetivene, B-vetivone, vetiverol, A-vetivone, and iso-eudesma sesquiterpene alcohol.

[0003] The essential oil and hydrolate of the root of the orchid grass have a wide application prospect (fragrance daily chemical, food and beverage, medicine and health care, etc.) due to their unique fragrance and biological activities such as insecticidal and antibacterial, and the market demand is increasing. The essential oil of the root of the orchid grass is relatively expensive, and the market demand is large, especially the high-quality essential oil, which is in short supply. The commercial planting of the orchid grass adopts the interval rotation method, which can scientifically and reasonably utilize the plant resources, plays a role in soil and water conservation, and produces a large amount of orchid grass root and stem raw materials every year.

[0004] At present, the essential oil and hydrolate of the orchid grass are mainly extracted by the methods of steam distillation, vacuum distillation, ultrasonic-assisted extraction, enzyme-assisted extraction, organic solvent extraction and supercritical fluid extraction (such as supercritical CO2 extraction). Among them, the steam distillation method is to put the root of the orchid grass into a distillation device, pass water vapor through the plant material by heating, take out the volatile components in the essential oil, and then separate to obtain the essential oil of the orchid grass. The organic solvent extraction is to extract the essential oil of the orchid grass by using an organic solvent (such as petroleum ether), put the dried root of the orchid grass into an extraction container, add an appropriate amount of organic solvent, then seal the container, and use a Soxhlet extractor device for extraction. The essential oil components in the root of the orchid grass are dissolved into the organic solvent by heating or stirring, and the extraction time is generally about 24 hours. The extraction liquid is filtered through filter paper or filter screen to remove the solid impurities and obtain clear extraction liquid. Then the filtered extraction liquid is concentrated to obtain the essential oil product. The existing extraction process has the following shortcomings in the extraction of the essential oil of the orchid grass:

[0005] 1) The traditional steam distillation method has the problems of long time consumption, high energy consumption, low yield of essential oil and low extraction rate of hydrolate in the process of extracting essential oil, which directly affects the economic benefit and market competitiveness of the product;

[0006] 2) The organic solvent extraction method has the problem of residual solvent affecting the safety of the essential oil product;

[0007] 3) The supercritical fluid extraction method needs special equipment and complex process operation, which leads to high production cost and long production cycle, and limits its large-scale application;

[0008] 4) Most of the existing extraction processes are focused on the optimization of single extraction method, and the comprehensive optimization research on process parameters (such as raw material pretreatment, extraction time and temperature, etc.) is insufficient, which leads to the difficulty in significantly improving the quality and yield of the essential oil and hydrolate, and the problems of low extraction rate of the essential oil of the orchid grass, long time consumption and impure fragrance;

[0009] 5), the rock orchid hydrolat is easy to breed microorganisms, especially in large-scale rock orchid hydrolat extraction production and storage, its preservation problem is particularly prominent, at present most hydrolat products adopt the way of zero addition, cannot guarantee the product quality under long-term preservation, lack effective, safe and economic hydrolat preservation method. SUMMARY

[0010] In order to solve the above problems, the present application provides a kind of green environmental protection, based on microwave-assisted steam distillation method and combined with raw material screening, pretreatment and process parameter optimization, can improve the extraction efficiency of rock orchid root essential oil and hydrolat, product quality and storage stability, reduce production cost and extraction time of rock orchid root essential oil and hydrolat extraction method and storage method.

[0011] In order to achieve the above purpose, the present application adopts the following technical solutions:

[0012] On the one hand, the present application provides a kind of rock orchid root essential oil and hydrolat extraction method, the extraction method includes the following steps:

[0013] Step 1) raw material pretreatment: the one-year-old rock orchid root harvested in the elongation stage is cut into 4-6cm root section, repeatedly washed with distilled water or tap water, dried to ≤12% moisture content, after air drying, the root section is mechanically pulverized by pulverizer with ≤200g / batch, after pulverization, sieve to obtain 60-100 mesh rock orchid powder, after treatment, rock orchid powder is stored at ≤-20℃;

[0014] Step 2) weighing: weighing pretreated rock orchid powder;

[0015] Step 3) mixing of material and liquid: placing rock orchid powder in microwave reactor, adding distilled water according to material and liquid mass volume ratio 1:8-1:15, forming mixed liquid;

[0016] Step 4) microwave treatment: placing the flask with the mixture of rock orchid powder and water in microwave equipment for microwave treatment, the power of microwave treatment is 450W-700W, the time of microwave treatment is 4min-6min;

[0017] Step 5) steam distillation: directly transferring the raw material after microwave treatment to steam distillation device, starting steam distillation within 5 minutes after microwave treatment ends, controlling the distillation temperature of water vapor to be 95-99℃, the distillation extraction time is 2.5-3.5 hours, synchronously monitoring pressure and maintaining ≤0.1MPa;

[0018] Step 6) Essential oil and hydrolat separation treatment: After the distillation is completed, the condenser is cooled by circulating cooling water, and an effective amount of salt reagent is added to the oil-water mixture in the receiving bottle. The receiving bottle is allowed to stand, and the oil-water mixture in the receiving bottle is allowed to separate into an upper layer of essential oil and a lower layer of hydrolat. The collected essential oil is dried and filtered to obtain the final essential oil product.

[0019] Further, in step 1), the drying is performed by any one of the following methods:

[0020] (a) Drying in a cool and ventilated place in the dark;

[0021] (b) Drying under air conditioning for 20-40 min.

[0022] Further, in step 4), the microwave device used in the microwave treatment is a microwave oven.

[0023] Further, in step 5), the water vapor distillation device is a 2L or 50L volatile oil extractor, and the water vapor distillation device needs to be sterilized with water vapor before distillation.

[0024] In step 5), zeolite is added to the distillation bottle of the volatile oil extractor, and the amount of zeolite added is 0.5-1% of the mass of the raw material.

[0025] Further, in step 6), the salt reagent added is sodium chloride, and the effective amount of the salt reagent added is to make the concentration of sodium chloride in the oil-water mixture reach 0.5% to 5% (w / v), and the standing time of the receiving bottle is 40 min-80 min.

[0026] Further, in step 6), the essential oil and hydrolat separation treatment includes:

[0027] Step 61) separating the oil layer by using a separatory funnel, separating the oil layer and the water layer, drying the separated oil layer, adding a drying agent to the oil layer, mixing the drying agent and the essential oil, and then placing them in a sealed container, and shaking them for at least 2 hours. After shaking, the drying agent and impurities are filtered out by a filtering device to obtain a vanilla essential oil product.

[0028] Step 62) collecting the separated water layer to obtain vanilla hydrolat.

[0029] Further, in step 61), the drying agent is anhydrous sodium sulfate, and the amount of anhydrous sodium sulfate added is 10%-20% of the weight of the essential oil, and the filtering device is filter paper or a glass fiber filter.

[0030] In another aspect, the present application also provides a preservation method of vanilla root hydrolat, which includes the following processes:

[0031] Step S1) heating the hydrolate extracted from the roots of the plantain to 85±2°C and maintaining the temperature for 8-12 min, and cooling to 25-30°C;

[0032] Step S2) adding a preservative to the cooled hydrolate; adding 1,2-hexanediol at a concentration of 0.8-3wt% to the hydrolate cooled to room temperature, and then heating the hydrolate to 65°C and adding p-hydroxyacetophenone at a concentration of 0.3-1.0wt% at this temperature;

[0033] Step S3) sealing the final hydrolate product obtained in step S2) in an amber glass bottle and storing in a light-proof environment at ≤15°C.

[0034] Further, in step S2), the preservative comprises 1,2-hexanediol at a concentration of 0.8-3wt% and p-hydroxyacetophenone at a concentration of 0.3-1.0wt%, wherein 1,2-hexanediol is added at a concentration of 1wt% after the hydrolate is cooled to room temperature, and p-hydroxyacetophenone is added at a concentration of 0.5wt% when the hydrolate is heated to 65°C. Based on considerations of strong bacteriostatic effect, synergistic effect, simplified formula, reduced potential risks, low irritation, and high safety, etc., the combination of 1,2-hexanediol and p-hydroxyacetophenone is the preferred solution for the preservative of the plantain root hydrolate, which can effectively extend the shelf life of the product while ensuring the safety of the product and the user experience. The combination of 1,2-hexanediol and p-hydroxyacetophenone exhibits high synergistic bacteriostatic effect (log reduction value >3.0 within 7 days), simplified formula safety (only 2 ingredients reduce the risk of allergy), and dual mild properties (both are certified by international cosmetic regulations).

[0035] Compared with the prior art, the technical scheme of the present application has at least the following beneficial effects:

[0036] 1), The extraction method of the application includes raw material pretreatment, weighing, mixing of feed liquid, microwave treatment, water vapor distillation, essential oil and hydrol distillation separation treatment, the application optimizes the raw material pretreatment, controls the uniform distribution of the particle size of the ophiopogon japonicus powder, effectively improves the utilization rate of the raw material and the extraction efficiency of the essential oil and the hydrol, avoids the influence of the non-uniformity of the particle size on the extraction efficiency of the essential oil and the hydrol, adopts the microwave assisted water vapor distillation method, the water in the plant tissue of the raw material is rapidly heated and vaporized by using the heat effect of the microwave, so that the structure of the plant matrix of the raw material is loose and expanded, the mass transfer resistance in the extraction process is reduced, in addition, the non-thermal effect of the microwave can weaken the molecular interaction between the components in the cell matrix of the raw material, enhance the desorption, and improve the solubility, so that the extraction effect is improved, the solvent consumption is reduced, the extraction rate of the essential oil and the hydrol of the ophiopogon japonicus is significantly improved after the optimized extraction method, the content of the vetiver in the essential oil is also improved, the aroma of the vetiver oil is improved, the aroma is pure, the extraction time is shortened, the extraction cost is reduced, which is beneficial to industrial production, and solves the problems of low "vetiver alcohol" and low "essential oil yield" in the traditional extraction method.

[0037] 2), The preservation method provided by the application can solve the technical problem that the ophiopogon japonicus hydrol is easy to breed microorganisms, by optimizing the preservation method, heating first and then cooling, and then adding a preservative, avoiding thermal decomposition of the preservative, the preservative adopts 1, 2-hexanediol and p-hydroxyacetophenone synergistic formula, solves the antibacterial problem of low osmotic pressure of the hydrol, the dehydrated ophiopogon japonicus essential oil is sealed and stored, is put into dry amber glass bottles, and is placed in a cool and dark place, so as to reduce the influence of oxidation and photolysis reaction on the quality of the essential oil. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 The flow chart of the extraction method of the ophiopogon japonicus root essential oil and hydrol of the application. DETAILED DESCRIPTION

[0039] The principle of the application will become apparent from the following detailed description, which is given by way of example only, and with reference to the accompanying drawings, in which like references refer to like elements. In the drawings:

[0040] As Figure 1 shown, in one aspect, the application provides an extraction method of ophiopogon japonicus root essential oil and hydrol, which comprises the following steps:

[0041] Step 1) raw material pretreatment: the roots of one-year-old Ophiopogon japonicus harvested at the jointing stage are cut into 4-6 cm root segments, washed repeatedly with distilled water or tap water to remove soil, impurities, etc., dried to a moisture content of ≤12%, and dried in the shade under ventilation or in an air-conditioned room for 20-40 min to avoid direct sunlight to cause degradation of effective components; the dried root segments are mechanically pulverized by a pulverizer at a rate of ≤200 g / batch, and sieved to obtain 60-100 mesh Ophiopogon japonicus powder; the treated Ophiopogon japonicus powder is stored at ≤-20℃; the uniform particle size distribution effectively improves the utilization rate of raw materials and the extraction efficiency of essential oil, and avoids the influence of uneven particle size on extraction efficiency;

[0042] Step 2) weighing: weighing the pretreated Ophiopogon japonicus powder;

[0043] Step 3) mixing of material and liquid: placing the Ophiopogon japonicus powder in a microwave reactor, adding distilled water at a material-to-liquid mass-to-volume ratio of 1:8-1:15 to form a mixed liquid;

[0044] Step 4) microwave treatment: placing the flask containing the mixture of Ophiopogon japonicus powder and water in a microwave device for microwave treatment; in specific implementation, the microwave device can be a microwave oven, wherein the microwave treatment power is 450 W-700 W, and the microwave treatment time is 4 min-6 min; the purpose of microwave treatment is to soften the cell wall of Ophiopogon japonicus and improve the dissolution rate of effective components, which is higher than that without microwave treatment;

[0045] Step 5) water vapor distillation: transferring the microwave-treated raw material directly to a water vapor distillation device, which can be a 2L or 50L volatile oil extractor; before distillation, the water vapor distillation device needs to be sterilized with water vapor; within 5 minutes after the microwave treatment is completed, start the water vapor distillation, add zeolite to the distillation flask of the volatile oil extractor, the amount of zeolite added is 0.5-1% of the mass of the raw material, control the distillation temperature of water vapor to be 95-99℃, and the distillation extraction time is 2.5-3.5 hours, while monitoring the pressure and maintaining it at ≤0.1 MPa; during the distillation process, the distillation temperature is controlled to 95-99℃, mainly to avoid degradation of effective components;

[0046] Step 6) Essential oil and hydrolate separation treatment: After the distillation is completed, the condenser is cooled by circulating cooling water after the water droplets stop flowing out, and the cooling water circulating machine is used instead of tap water cooling, which can improve the aroma concentration of the hydrolate. An effective amount of salt reagent is added to the oil-water mixture in the receiving bottle, and the added salt reagent can be sodium chloride. The effective amount of the added salt reagent is 0.5% to 5% (w / v) of the concentration of sodium chloride in the oil-water mixture. The addition of the salt reagent can accelerate the separation of the essential oil. The receiving bottle is placed for 40 to 80 minutes, and the oil-water mixture in the receiving bottle is separated into upper and lower layers. The upper essential oil and the lower hydrolate are collected separately, and the collected essential oil is dried and filtered.

[0047] The extraction method of the present application includes raw material pretreatment, weighing, mixing of liquid and solid, microwave treatment, water vapor distillation, and essential oil and hydrolate separation treatment. By optimizing the raw material pretreatment, the particle size distribution of the vanilla powder is uniform, the utilization rate of the raw material is effectively improved, and the extraction efficiency of the essential oil and the hydrolate is improved. The influence of particle size non-uniformity on the extraction efficiency of the essential oil and the hydrolate is avoided. The extraction rate of the vanilla essential oil and the hydrolate is significantly improved. The microwave-assisted water vapor distillation method is adopted. The water in the plant tissue of the raw material is rapidly heated and vaporized by the heat effect of the microwave, which causes the plant matrix structure to become loose and expand, reduces the mass transfer resistance in the extraction process, and has a non-thermal effect. The molecular interaction between the components in the cell matrix of the raw material is weakened, the desorption is enhanced, and the solubility is improved, thereby achieving the purpose of improving the extraction effect and reducing the solvent consumption. The optimized extraction method can ensure that the extracted essential oil and the odor, color, and effective ingredient content meet higher standards. The optimized process simplifies the operation steps and reduces the production cost.

[0048] In the extraction method of the present application, the essential oil and hydrolate separation treatment specifically includes the following processes:

[0049] Step 61) The oil layer is separated by using a separatory funnel, and the separated oil layer is dried. A drying agent is added to the oil layer, and the drying agent can be anhydrous sodium sulfate. The amount of anhydrous sodium sulfate added is 10% to 20% of the weight of the essential oil. The drying agent and the essential oil are thoroughly mixed and then placed in a sealed container. The container is shaken vigorously for at least 2 hours. After shaking, the drying agent and impurities are filtered out by using a filter device, which can be filter paper or a glass fiber filter. The vanilla essential oil product is obtained. The dehydrated vanilla essential oil needs to be used immediately or stored in a sealed manner. It is packed in a dry amber glass bottle and stored in a cool and dark place. It can be stored for a long time and can reduce the influence of oxidation and photolysis reaction on the quality of the essential oil.

[0050] Step 62) The separated water layer is collected to obtain the vanilla hydrolate.

[0051] In another aspect, the present application also provides a preservation method of the pure distillate from the roots of the orchid grass, which comprises the following processes:

[0052] Step S1) heating the pure distillate extracted from the roots of the orchid grass to 85±2℃ and keeping for 8-12 min, and cooling to 25-30℃;

[0053] Step S2) adding a preservative to the cooled pure distillate; adding 1,2-hexanediol with a concentration of 0.8-3wt% to the pure distillate cooled to room temperature, and then heating the pure distillate to 65℃ and adding p-hydroxyacetophenone with a concentration of 0.3-1.0wt% at this temperature;

[0054] Step S3) sealing the final pure distillate product obtained in step S2) in an amber glass bottle and storing in a light-proof environment at ≤15℃.

[0055] In step S2), the preservative only includes the preservative combination of 1,2-hexanediol and p-hydroxyacetophenone, wherein the concentration of 1,2-hexanediol is 0.8-3wt%, the concentration of p-hydroxyacetophenone is 0.3-1.0wt%, 1wt% of 1,2-hexanediol is added after the pure distillate is cooled to room temperature, and 0.5wt% of p-hydroxyacetophenone is added when the pure distillate is heated to 65℃. The preservation method provided by the present application can solve the technical problem of easy breeding of microorganisms in the pure distillate of the orchid grass. Through optimization of the preservation method, the preservative is added after heating and cooling, which avoids thermal decomposition of the preservative. The preservative uses a synergistic formula of 1,2-hexanediol and p-hydroxyacetophenone to solve the problem of low osmotic pressure of the pure distillate. The dehydrated orchid grass essential oil is sealed and stored in a dry amber glass bottle and placed in a cool and light-proof place to reduce the influence of oxidation and photolysis reaction on the quality of the essential oil. The preservation method used in the present application can break through the technical prejudice that the pure distillate extracted from the orchid grass has a short storage period.

[0056] The specific parameters of the equipment used in the preservation method of the present application are shown in Table 1 below:

[0057]

[0058]

[0059] Table 1

[0060] I. In order to facilitate the understanding of those skilled in the art, the following provides test instructions. Through optimization of the pretreatment of raw materials, the yield of essential oil and pure distillate can be improved.

[0061] (I) Single-factor test design and verification of raw material pretreatment

[0062] 1) Test purpose: To verify the influence of "crushing process" and "particle size control" in raw material pretreatment process on the extraction efficiency of O. japonicus root essential oil, and to determine the optimal pretreatment parameters to improve the utilization rate of raw materials.

[0063] 2) Test design principles: Single factor variable method is adopted, "crushing or not" and "particle size range" are controlled as independent variables, other pretreatment conditions (such as harvesting period, cleaning method, drying process, etc.) are kept consistent, and the best process parameters are determined by comparing the essential oil yield and ingredient stability under different variable levels.

[0064] 3) Single factor test variables and levels, as shown in Table 2 below

[0065]

[0066] Table 2

[0067] 4) Test implementation steps

[0068] Raw material uniform pretreatment

[0069] Take the annual O. japonicus root harvested at the jointing stage, cut into 5 cm root segments, and rinse with distilled water until there are no dirt impurities;

[0070] Use cool and ventilated air drying (moisture content ≤12%) or air conditioning drying for 48 hours to avoid direct sunlight;

[0071] Except for the non-crushing group, the rest of the groups are crushed by 200g / batch using a crusher, and are passed through different mesh screens to control the uniform distribution of powder particle size.

[0072] 5) Single factor test grouping

[0073] Crushing or not comparison group: Dry root segments are divided into two groups, one group is crushed through 60-80 mesh screen, and the other group is not crushed, and essential oil is extracted according to the above extraction method, and the yield and ingredient content are recorded.

[0074] Particle size gradient group: The crushed powder is divided into five groups according to the particle size range, and the same extraction process is used for each group to compare the essential oil yield, purity and extraction time under different particle sizes.

[0075] 6) Detection index and method

[0076] Essential oil yield (g / 100g raw material): weighing method;

[0077] Effective ingredient content (such as oridonin, oridonol, etc.): GC-MS analysis;

[0078] Particle size uniformity: Laser particle size analyzer is used to detect the particle size distribution of the powder.

[0079] 7) Test results and conclusions

[0080] The yield of essential oil extracted from the crushed group raw material was 23-35% higher than that from the uncrushed group raw material, confirming that crushing the raw material can significantly improve the extraction efficiency, as the contact area between the crushed raw material and the solvent increases, and the dissolution rate of the active ingredients accelerates.

[0081] Particle size optimization results: The essential oil yield of 60-80 mesh powder was the highest (3.25%), and the ingredient stability was the best; the particle size of 120-140 mesh powder was too fine, which easily led to powder agglomeration, increased the viscosity of the extraction liquid, and reduced the mass transfer efficiency; the particle size of 40-60 mesh powder was too coarse, and the specific surface area was insufficient, which prolonged the extraction time.

[0082] Example 1

[0083] An extraction method of a vetiveria zizanioides root essential oil and a hydrolate, the extraction method comprising the following steps:

[0084] Step 1) Raw material pretreatment: cutting the annual vetiveria zizanioides roots harvested at the jointing stage into 5 cm root segments, repeatedly washing with distilled water or tap water, drying to a moisture content of 12%, and mechanically crushing the dried root segments at a rate of 200 g per batch using a crusher, then sieving the crushed product to obtain 80 mesh vetiveria zizanioides powder, and storing the treated vetiveria zizanioides powder at -20°C;

[0085] Step 2) Weighing: weighing 200 g of the pretreated vetiveria zizanioides powder;

[0086] Step 3) Mixing of material and liquid: placing the vetiveria zizanioides powder in a microwave reactor, adding distilled water at a material-to-liquid mass-to-volume ratio of 1:10, and gently stirring to disperse the vetiveria zizanioides powder uniformly to form a mixed liquid;

[0087] Step 4) Microwave treatment: placing the flask containing the mixture of vetiveria zizanioides powder and water in a microwave device for microwave treatment, the power of the microwave treatment being 700 W, and the time of the microwave treatment being 4 min;

[0088] Step 5) Water vapor distillation: directly transferring the microwave-treated raw material to a water vapor distillation device, starting water vapor distillation within 5 minutes after the end of the microwave treatment, controlling the distillation temperature of the water vapor to be 99°C, and controlling the distillation extraction time to be 3.5 hours, while monitoring and maintaining the pressure at 0.1 MPa;

[0089] Step 6) Essential oil and hydrol distillation separation treatment: after the distillation is completed, the condenser is cooled by circulating cooling water after the water droplets stop flowing, an effective amount of salt reagent is added to the oil-water mixture in the receiving bottle, the receiving bottle is placed for 60 min, the oil-water mixture in the receiving bottle is separated into upper layer essential oil and lower layer hydrol, the collected essential oil is dried and filtered to obtain the final essential oil product.

[0090] Comparative Example 1

[0091] Traditional steam distillation (SHD) extraction of essential oil and hydrol: without microwave pretreatment, other procedures are consistent with the raw material, liquid ratio, distillation temperature, and essential oil and hydrol separation treatment of Example 1 above, direct steam distillation, and the distillation time is 12 h.

[0092] Comparative Example 2

[0093] Waterless distillation method for extracting essential oil and hydrol: other procedures are consistent with the raw material, liquid ratio, essential oil and hydrol separation treatment of Example 1 above, and the distillation is heated for 16 h using a double-layer container and dried for 1 h.

[0094] Comparative Example 3

[0095] Organic solution distillation method for extracting essential oil and hydrol: solvent soaking for 2 h, distillation for 8 h, solvent recovery for 1 h, and residual detection for 0.5 h.

[0096] Example 2

[0097] The application also provides a preservation method for the hydrol extracted from the roots of the orchid grass, which comprises the following processes:

[0098] Step S1) heating the hydrol extracted from the roots of the orchid grass to 85℃ and keeping it for 8-12 min, and cooling it to 25℃;

[0099] Step S2) adding a preservative to the cooled hydrol; adding 1,2-hexanediol with a concentration of 1wt% to the hydrol cooled to room temperature, and then heating the hydrol to 65℃ and adding p-hydroxyacetophenone with a concentration of 0.5wt% at this temperature;

[0100] Step S3) sealing the final hydrol product obtained in Step S2) in an amber glass bottle and storing it in a light-proof environment at ≤15℃.

[0101] Control group

[0102] Without preservation treatment, the hydrol is consistent with the hydrol of Example 2 without preservation treatment.

[0103] II. Test and compare the chemical components of the essential oil obtained in Example 1 above and the essential oil obtained in Comparative Example 1 (traditional steam distillation method), and the test conditions are as follows:

[0104] 1. Detection method: calculate the yield of essential oil according to the following formula:

[0105] Essential oil yield (%) =

essential oil weight (g) / raw material dry weight (g)

[0106] Wherein, the raw material dry weight = the weight of the root of the orchid grass before extraction x (1 - the moisture content of the dry root);

[0107] The volatile components in the essential oil are analyzed by gas chromatography-mass spectrometry (such as Agilent 7890A-5975C), and the detection conditions are as follows:

[0108] Chromatographic column: DB-5MS capillary column (30 m x 0.25 mm x 0.25 μm);

[0109] Programmed temperature: initial temperature 50℃, increased to 250℃ at 5℃ / min, and maintained for 10 min;

[0110] Ion source: EI ion source (70 eV);

[0111] Detection components: including key effective components (characteristic components such as zedoary ketone and zedoary alcohol), aroma components, efficacy components (anti-inflammatory, antibacterial, etc.), antioxidant components;

[0112] Calculation method: calculate the relative content (%) of each component by peak area normalization method;

[0113] Zedoary alcohol purity determination: Shimadzu LC-20A type high performance liquid chromatograph is used to determine the purity of zedoary alcohol (μg / g), and the chromatographic conditions are as follows: mobile phase is methanol-water (85:15), flow rate is 1.0 mL / min, detection wavelength is 210 nm, and external standard method is used for quantitative determination.

[0114] 2. Detection results: the essential oil extracted in Example 1 and the essential oil extracted in Comparative Example 1 are detected according to the above detection method, and the detection results are shown in Table 3 as follows:

[0115]

[0116]

[0117] Table 3

[0118] 4、Result analysis: As shown in Table 3, compared with the traditional water vapor distillation method (comparative example 1), the extraction method of the present application (example 1) has the following advantages: significant enrichment of active ingredients: the content of total sesquiterpene alcohols (with calming, anti-inflammatory and other core functions) is increased by 14.15%, among which the content of core aroma component and antibacterial active ingredient vetiverol is increased by 10.69%, the content of anti-inflammatory component kusunokinol and fixed aroma component isohydroxyvetiverol is significantly improved, indicating that the extraction method of the present application can directionally enrich the functional components in the essential oil, and enhance its medicinal and aromatic functions; reasonable reduction of non-core components: the contents of sesquiterpene (auxiliary function) and sesquiterpene ketone (partial antibacterial function) are reduced by 5.67% and 5.17% respectively, indicating that the method can reduce the proportion of non-core components and improve the purity of essential oil; more comprehensive component identification: the total identification rate is 99.08%, which is increased by 3.08% compared with comparative example 1, indicating that the essential oil extracted by the extraction method of the present application is more clear, which is beneficial to quality control and standardized production. Therefore, the extraction method of the present application can effectively increase the content of key functional components in the essential oil of anemarrhena asphodeloides, optimize the quality of essential oil, and has significant technical advantages.

[0119] (ii) Effect of microwave treatment on the extraction of essential oil from anemarrhena asphodeloides

[0120] 1. The time consumed for extracting essential oil of example 1, the essential oil extraction rate and the time consumed for extracting essential oil of comparative example 1, comparative example 2 and comparative example 3, the essential oil extraction rate were compared, and the comparison is shown in Table 4:

[0121]

[0122] Table 4

[0123] 2、Result analysis: As shown in Table 4, the extraction rate of the essential oil obtained by the extraction method of the present application is significantly higher than that of the traditional water distillation method and the waterless distillation method, and is equivalent to that of the organic solution distillation method, but the extraction method of the present application does not need to rely on chemical solvents, the extraction method of the present application is physically layered by 1% sodium chloride, and there is no chemical solvent residue (no organic solvent peak is detected by gas chromatography); traditional water distillation (non-water separation): long time high temperature (above 100 DEG C) leads to about 15% thermal sensitive components degradation, purity 90-92%, no solvent residue; waterless distillation: uneven heat transfer leads to local temperature up to 110-120 DEG C, 20-25% active ingredients are oxidized or hydrolyzed, purity 85-88%; organic solution distillation: n-hexane residue is 0.05-0.1% (exceeding 0.01% of the food grade essential oil standard), and the solvent may react with part of the components; the total time of the extraction method of the present application is about 4.0h, the process is simple, and no complex post-treatment is needed; the distillation time of the traditional water distillation (non-water separation) is 3.4 times of the present application; the total time of the waterless distillation method is 15-17h, and the energy consumption is concentrated in the long time heating stage; the total time of the organic solution distillation method is 9.5-11.5h, and additional solvent recovery and residue detection are needed, and the process is complicated. Therefore, the combination process of the present application by microwave assisted water distillation can ensure that the extraction rate (≥2.15%) is better than that of most traditional methods, at the same time, the problems of high energy consumption of traditional waterless distillation, solvent residue and high cost of organic solution distillation are solved, the high efficiency, high quality and low cost extraction of essential oil is realized, and the present application has significant industrial application value.

[0124] III. Test the yield and acid value, ester value and other key physicochemical property indexes of the essential oil extracted from the above example 1

[0125] (I) Essential oil yield detection

[0126] 1. Purpose of detection: compare the yield difference of the essential oil extracted by the microwave assisted water vapor distillation extraction method of the above example 1 and the traditional water vapor distillation method of comparative example 1:

[0127] 2. Detection method: essential oil yield (%) refers to the essential oil yield, wherein:

[0128] Essential oil yield (%) =

essential oil weight (g) / raw material dry weight (g)

[0129] Among them, the raw material dry weight = the weight of the root of the orchid grass before extraction x (1-dry root moisture content).

[0130] 3. Detection result: the essential oil yield and the essential oil yield of comparative example 1 are detected according to the above detection method, and the detection results are shown in the following table 5:

[0131]

[0132]

[0133] Table 5

[0134] 4、Result analysis: compared with the traditional steam distillation method, the extraction method of the present application embodiment 1 can significantly improve the yield of essential oil, the yield of essential oil of the present application is 2.15±0.08%, which is increased by 216.2% compared with the traditional method of comparative example 1 (0.68±0.05%); the extraction method of the present application can improve the purity of effective components, the purity of vetiverol in the extracted essential oil reaches 920.39±15.2μg / g, which is increased by 41.6% compared with the traditional method of comparative example 1 (650.00±20.5μg / g); the extraction method of the present application can improve the resource utilization rate, the hydrolate yield is 85.3±1.2%, which is increased by 36.0% compared with the traditional method of comparative example 1 (62.7±2.1%); the extraction method of the present application embodiment 1 can reduce energy consumption and time, the total time consumption is only 250 minutes, which is reduced by 30.6% compared with the traditional method of comparative example 1 (360 minutes), and the steam consumption is 1.8kg / kg raw material, which is reduced by 40.0% compared with the traditional method (3.0kg / kg raw material).

[0135] (II) Detection of physicochemical properties of vetiver essential oil

[0136] 1、Detection basis: the physicochemical indexes of the essential oil of vetiver of the present application and comparative example 1 were detected, the detection basis was international standard ISO 4716-2013 "international standard of vetiver essential oil" and national standard GB / T 26516-2011 "general test method of essential oil"; the specific detection method of each index was as follows:

[0137] Essential oil yield: weighing method (based on the dry weight of raw materials);

[0138] Relative density (20℃): determined according to GB / T 11540-2008 "determination of relative density of spices";

[0139] Refractive index (20℃): determined according to GB / T 14454.4-2008 "determination of refractive index of spices";

[0140] Optical rotation (20℃): determined according to GB / T 14454.5-2008 "determination of optical rotation of spices";

[0141] Acid value: determined according to GB / T 14455.5-2008 "determination of acid value or acid content of spices";

[0142] Ester value: determined according to GB / T 14455.6-2008 "determination of ester value or ester content of spices";

[0143] vetiverol content: determined by GC-MS method (referring to ISO 11024-2013 standard);

[0144] vetiverol purity: determined by HPLC method (referring to ISO 11024-2013 standard).

[0145] 2, test results: the physicochemical indexes of the essential oil of phalaris arundinacea extracted by example 1 and the physicochemical indexes of the essential oil of phalaris arundinacea extracted by traditional process (traditional steam distillation method) of comparative example 1 were detected according to the above detection basis, and the test results are shown in table 6,

[0146]

[0147]

[0148] Table 6

[0149] 3、Result analysis: As shown in Table 6, compared with the traditional water vapor distillation method, the extraction method of Example 1 of the present application significantly improves the production efficiency, and the yield of essential oil of Example 1 of the present application is 2.15±0.08%, which is much higher than 0.68±0.05% of Comparative Example 1, indicating that the method of the present application can greatly improve the extraction efficiency of the essential oil of the orchid grass, and in industrial production, the yield improvement can reduce the consumption of raw materials, improve the unit production capacity, and has significant economic value; the relative density (20℃), refractive index (20℃) and optical rotation (20℃) of Example 1 and Comparative Example 1 all meet the range of ISO 4716-2013 international standard, proving that the essential oils extracted by the two methods are all qualified products, but the optical rotation of Example 1 (+42.5°±0.5°) is closer to the upper limit of the standard (+48°), and the optical rotation is a key indicator reflecting the proportion of optically active components in essential oil, indicating that the active ingredient distribution of the essential oil extracted by the method of the present application is more optimal; the acid value (12.3±0.5mg KOH / g) of Example 1 of the present application is lower than that of Comparative Example 1 (18.6±0.7mg KOH / g), and the ester value (28.7±1.2mg KOH / g) is higher than that of Comparative Example 1 (22.4±1.5mg KOH / g), which indicates that the content of free fatty acid in the essential oil is low, and the risk of oxidation and deterioration is low; the high ester value indicates that the ester component (main carrier of aroma) is more abundant, indicating that the storage stability and aroma quality of the essential oil of the present application are more optimal. The content of vetiverol, the core active ingredient of orchid grass essential oil, directly determines the efficacy and grade of essential oil, and the content of vetiverol of Example 1 of the present application is 75.69±0.8%, which is much higher than 65.00±1.2% of Comparative Example 1, and both of them are much higher than the standard of 'high-quality essential oil ≥40%'; moreover, the purity of vetiverol (920.39±15.2μg / g) of Example 1 of the present application is significantly higher than that of Comparative Example 1 (650.00±20.5μg / g), which indicates that the essential oil prepared by the extraction method of the present application can more efficiently retain and enrich vetiverol, greatly improving the core quality and application value of the essential oil (such as stronger efficacy in the field of spices and medicine).

[0150] III. Test the sensory indicators and key indicators of the hydrolate extracted in the above Example 1

[0151] (I) Test the sensory indicators of the hydrolate

[0152] 1. Sensory indicator detection method

[0153] 1) Detection method of appearance: take 50mL of the hydrolate sample extracted in the above Example 1 and place it in a transparent glass container, and observe it with the naked eye under natural light;

[0154] 2) Detection method of aroma type: more than 5 professional smellers evaluate the sample under room temperature (25±2℃);

[0155] 3) Clarity detection method: After the sample is filtered through a 0.45 μm filter membrane, the absorbance is measured at 600 nm (or the naked eye is observed without obvious impurities, black spots);

[0156] 4) Tactile detection method: A small amount of hydrolate is applied to the inner skin of the forearm of a healthy volunteer, and the observation is made after 30 minutes of retention;

[0157] 2, Test results: The sensory indicators of the hydrolate extracted in Example 1 of the application were tested according to the above detection methods, and the test results are shown in Table 7 below:

[0158] Indicators Indicator requirements Appearance Liquid, with a small amount of oil of spearmint floating on the surface Fragrance type Special sandalwood and earthy fragrance Clarity Water is transparent, with no obvious impurities and black spots Touch Cool and comfortable after application, no discomfort, no irritation and damage to the application site

[0159] Table 7

[0160] (I) Hydrolate yield and key indicator detection

[0161] 1, Detection method: The hydrolate obtained in Example 1 above and the hydrolate obtained in Comparative Example 1 were detected for the following indicators respectively:

[0162] Hydrolate yield: Volumetric method (based on total condensate), calculate the percentage of hydrolate volume to total condensate volume, repeat 3 times and take the average value;

[0163] Water-soluble zizanin content: detected by high performance liquid chromatography (HPLC), the chromatographic column is C18 column, the detection wavelength is 280 nm, the mobile phase is methanol-water (volume ratio 60:40), the flow rate is 1.0 mL / min, the external standard method is used for quantitative determination, repeated 3 times and take the average value;

[0164] Total phenol content: Folin-Ciocalteu method, with gallic acid (GAE) as the reference substance, the absorbance was measured at 765 nm, and the total phenol content (mg GAE / L) was calculated, repeated 3 times and take the average value;

[0165] 3, Detection results: The yield and key indicators of the hydrolate extracted in Example 1 and the yield and key indicators of the hydrolate extracted in Comparative Example 1 were detected according to the above detection methods, and the detection results are shown in Table 8 below:

[0166]

[0167] Table 8

[0168] 4、Result analysis: As shown in Table 8, the yield of the extract hydrolat of Example 1 of the present application is increased by 13.3% compared with the traditional process, indicating that the extraction method of the present application can significantly improve the utilization rate of raw materials, reduce the production cost, and meet the needs of industrial production; the extraction method of the present application can increase the content of water-soluble zingiberol and total phenol, which are increased by 51.7% and 54.3% respectively, and zingiberol is the characteristic active ingredient of hydrolat, and total phenol is the key antioxidant substance, indicating that the extraction method of the present application can retain more active ingredients and enhance the skin care activity (such as antioxidant and soothing) of hydrolat.

[0169] (II) Detection of physicochemical indexes in hydrolat

[0170] 1. Detection method: The following physicochemical indexes were detected by using the detection method conforming to the industry / international standard:

[0171] pH value (25℃): detected according to GB / T 13531-2023 "Cosmetic General Test Methods", measured directly using a calibrated pH meter, repeated 3 times, and the average value was taken;

[0172] Conductivity (μS / cm): detected according to ISO 7888:1985;

[0173] Turbidity (NTU): detected according to ISO 7027:1999;

[0174] Density (g / mL, 20℃): detected according to GB / T 4472-2011.

[0175] 2. Detection condition: The physicochemical indexes of the hydrolat extracted in Example 1 and the physicochemical indexes of the hydrolat extracted in Comparative Example 1 were detected according to the above detection method, and the detection results are shown in Table 9:

[0176] Test indicators Example 1 Comparative Example 1 pH value (25℃) 5.2±0.1 5.8±0.2 Conductivity (μS / cm) 320±15 210±20 Turbidity (NTU) 1.5±0.2 3.8±0.5 Density (g / mL, 20℃) 1.002±0.001 0.998±0.002

[0177] Table 9

[0178] 3、Result analysis: As shown in Table 9, the hydrolat obtained by the extraction method has significant advantages compared with the traditional steam distillation method. The pH value of the hydrolat obtained by the extraction method is 5.2±0.1 (25℃), which is closer to the weak acid stability interval than 5.8±0.2 of the traditional process, indicating that the chemical stability is better and it is more conducive to storage. The conductivity of the hydrolat obtained by the extraction method is 320±15 μS / cm, which is increased by 52.4% compared with the traditional process, indicating that the content of soluble active ingredients in the hydrolat is higher, which is consistent with the mechanism of microwave-assisted process promoting the dissolution of ingredients. The turbidity of the hydrolat obtained by the extraction method is 1.5±0.2 NTU, which is reduced by 60.5% compared with the traditional process, indicating that the impurities in the hydrolat are less and the clarity is better. The density of the hydrolat obtained by the extraction method is 1.002±0.001 g / mL (20℃, GB / T 4472-2011), which meets the density characteristics of saturated hydrolat, proving that the process can more fully extract the effective components in the orchid.

[0179] (III) Detection of water-soluble active ingredients in the hydrolat

[0180] 1、Detection method: The hydrolat obtained in Example 1 and the hydrolat obtained in Comparative Example 1 were detected for the following indexes respectively:

[0181] Water-soluble geniposide

[0182] Detection method: HPLC method

[0183] Instrument and reagent: Agilent 1260 high performance liquid chromatograph; water-soluble geniposide standard (purity ≥98%, Sigma company); methanol (chromatographic pure), ultrapure water (18.2 MΩ·cm).

[0184] Chromatographic conditions: C18 chromatographic column (250 mm x 4.6 mm, 5 μm); mobile phase is methanol-water (60:40, v / v); flow rate 1.0 mL / min; column temperature 30℃; detection wavelength 280 nm; injection volume 10 μL.

[0185] Operation steps: Take 1 ml of the hydrolat extracted in Example 1 as the test sample and 1 ml of the hydrolat extracted in Comparative Example 1 as the comparison sample, filter through a 0.45 μm filter membrane, and inject for determination; draw a standard curve with the standard concentration as the abscissa and the peak area as the ordinate, and calculate the content of water-soluble geniposide in the sample (determine in triplicate, take the average value±standard deviation).

[0186] Total phenol (calculated as gallic acid)

[0187] Detection method: Folin-Ciocalteu method

[0188] Reagent: Folin-Ciocalteu reagent (diluted 10 times); 10% sodium carbonate solution; gallic acid standard (purity ≥ 98%).

[0189] Operation steps: Take 0.5 mL of the hydrolate obtained in Example 1 as the test sample, and take 0.5 mL of the hydrolate of Comparative Example 1 as the comparative sample, add 2.5 mL of Folin-Ciocalteu reagent, shake well and stand for 3 min, add 2 mL of 10% sodium carbonate solution, react at 25°C for 30 min in the dark, and measure the absorbance at 765 nm; draw a standard curve with the gallic acid standard solution, and calculate the total phenol content (determined in triplicate, and take the average ± standard deviation).

[0190] Flavonoids (calculated as rutin)

[0191] Detection method: aluminum salt complex spectrophotometry

[0192] Reagent: 5% sodium nitrite solution; 10% aluminum nitrate solution; 4% sodium hydroxide solution; rutin standard (purity ≥ 98%).

[0193] Operation steps: Take 1 ml of the hydrolate extracted in Example 1 as the test sample, and take 1 ml of the hydrolate extracted in Comparative Example 1 as the comparative sample, add 0.3 mL of 5% sodium nitrite solution, shake well and stand for 6 min, add 0.3 mL of 10% aluminum nitrate solution, shake well and stand for 6 min, add 4 mL of 4% sodium hydroxide solution, dilute to 10 mL, react at 25°C for 15 min in the dark, and measure the absorbance at 510 nm; draw a standard curve with the rutin standard solution, and calculate the flavonoid content (determined in triplicate, and take the average ± standard deviation).

[0194] Total organic acid

[0195] Detection method: titration method (refer to GB / T 12456-2021 "Determination of total acid in food")

[0196] Reagent: 0.1 mol / L sodium hydroxide standard solution (calibrated); phenolphthalein indicator (1% ethanol solution).

[0197] Operation steps: Take 20 ml of the hydrolate extracted in Example 1 as the test sample, and take 20 ml of the hydrolate extracted in Comparative Example 1 as the comparative sample, add 2 drops of phenolphthalein indicator, titrate with 0.1 mol / L sodium hydroxide standard solution until the solution turns pink and does not fade for 30 s, and record the consumption volume; calculate the total acid content (calculated as citric acid, determined in triplicate, and take the average ± standard deviation).

[0198] 2、Detection results: The water-soluble active ingredient content of the extract of Phlox paniculata pure hydrolat of Example 1 and the water-soluble active ingredient content of the Phlox paniculata pure hydrolat extracted by Comparative Example 1 were detected according to the above detection method, and the detection results are shown in Table 10 below:

[0199]

[0200]

[0201] Table 10

[0202] 3、Result analysis: As can be seen from Table 10, the water-soluble dihydromadeficin, total phenol, flavonoid and total organic acid contents of the Phlox paniculata pure hydrolat (test sample) obtained by the extraction method of the present application are significantly higher than those of the Phlox paniculata pure hydrolat (comparison sample B) prepared by the traditional method of Comparative Example 1, with an increase of 51.7%, 54.3%, 46.7% and 36.7%, respectively. Among them, water-soluble dihydromadeficin is a characteristic active ingredient of Phlox paniculata pure hydrolat, and its content increase can enhance the soothing and repairing effect of the product; total phenol and flavonoid have excellent antioxidant activity, and their content increase can enhance the free radical scavenging ability of the pure hydrolat; the increase of total organic acid content helps to adjust the pH value of the pure hydrolat, and improves the product stability and skin compatibility. The above result analysis proves that the extraction method of the present application can effectively reduce the loss of water-soluble active ingredients during the preparation process, significantly improve the retention rate of active ingredients of Phlox paniculata pure hydrolat, and solve the technical problems of easy degradation and low content of active ingredients in the traditional method.

[0203] (IV) Microbial limit test of pure hydrolat

[0204] 1、Detection items and standards:

[0205] Total bacterial count, mold and yeast: detected according to ISO 16212:2017 "Cosmetic Microbiology Test Total Viable Count Determination", with the counting unit of CFU / mL;

[0206] Escherichia coli: detected according to GB 4789.3-2016 "National Food Safety Standard Food Microbiological Examination Escherichia coli Counting";

[0207] Staphylococcus aureus: detected according to GB 4789.10-2016 "National Food Safety Standard Food Microbiological Examination Staphylococcus aureus Test".

[0208] 2. Detection method: Take 1 ml of the hydrosol extracted in Example 1 of this invention as the test sample, and take 1 ml of the hydrosol extracted in Comparative Example 1 as the control sample. Perform total bacterial count culture (36℃±1℃, 48h±2h) and mold and yeast culture (25℃±1℃, 5d±1d) according to the plate count method specified in ISO 16212:2017, and count the number of colonies. Pathogenic bacteria detection is performed by enrichment, isolation culture and identification according to the corresponding national standards.

[0209] 3. Test Results: The microbial limits of the hydrosol in Example 1 of this invention are compared with those of the hydrosol in Comparative Example 1 in Table 11 below:

[0210]

[0211] Table 11

[0212] 4. Results Analysis: As shown in Table 11, the vetiver hydrosol obtained by the extraction method of this invention effectively inhibited bacterial growth, with a total bacterial count <10 CFU / mL, far lower than the 1.2 × 10⁻⁶ CFU / mL of traditional hydrosols. 3 The concentration of CFU / mL was significantly lower than the safety limit (≤1000 CFU / mL). The hydrosol obtained by the extraction method of this invention did not contain any molds or yeasts, while the concentration of traditional hydrosols was 45±8 CFU / mL, which is close to the safety limit. This indicates that the preservation method of this invention can completely block the growth environment of molds and yeasts. Neither Escherichia coli nor Staphylococcus aureus were detected, which meets the safety requirement of "not detectable". This shows that this invention retains the efficacy of hydrosols without introducing the risk of pathogenic bacteria.

[0213] (V) Testing the heat and cold resistance of hydrosols

[0214] 1. Testing indicators and standards:

[0215] Heat resistance test: Take 80ml of hydrosol from Example 1 of the present invention as the test sample and 80ml of hydrosol from Comparative Example 1 as the control sample. Seal the test sample and the control sample in transparent glass containers respectively, place them in a constant temperature incubator at 48℃ for 24h, take them out and let them return to room temperature. Visually observe whether there is layering or precipitation, and evaluate whether there is an odor by smell. Record the phenomena.

[0216] Cold resistance test: "Take 80ml of the hydrosol from Example 1 of this invention as the test sample and 80ml of the control group hydrosol as the comparison sample. Seal the test sample and the comparison sample in transparent glass containers respectively, place them in a -10℃ low temperature freezer for 24h, take them out and let them naturally return to room temperature, observe whether there is crystal precipitation and the transparency of the solution by visual observation, and record the phenomenon.

[0217] 2, the heat and cold resistance of the hydrolat extracted by the embodiment 1 of the present application and the heat and cold resistance of the hydrolat extracted by the comparative example 1 are compared as shown in the following table 12:

[0218]

[0219] Table 12

[0220] 3, result analysis: from the above table 12, it can be known that the heat and cold resistance of the hydrolat prepared by the microwave-assisted method of the present application is obviously better than that of the hydrolat extracted by the traditional method, the hydrolat obtained by the extraction method of the present application has no stratification, precipitation and peculiar smell at 48℃ high temperature, while the hydrolat obtained by the extraction of the comparative example 1 appears slight flocculation, which shows that the extraction method of the present application can improve the stability of the hydrolat in high-temperature storage (such as summer transportation); the hydrolat obtained by the extraction method of the present application restores to be transparent without crystallization after low temperature of-10℃, while the hydrolat obtained by the extraction of the comparative example 1 precipitates white crystals, which shows that the extraction method of the present application is less likely to generate analysis in low-temperature environment (such as winter storage), and guarantees the appearance and efficacy stability of the hydrolat. The heat resistance and cold resistance of the hydrolat are significantly improved by the microwave-assisted technology of the present application, and the technical problem of poor storage stability of the hydrolat prepared by the traditional method is solved.

[0221] III, the microbial limit and stability of the hydrolat obtained by the preservation method of the above embodiment 2 and the hydrolat of the control group (without using the preservation method) are tested and compared, and the test conditions are as follows:

[0222] (I) stability accelerated test of hydrolat

[0223] 1, test conditions: the hydrolat obtained by the preservation method of the embodiment 2 of the present application and the hydrolat extracted by the control group are respectively subjected to stability accelerated test: the two kinds of hydrolat are placed in a constant temperature and humidity box, and the test conditions are controlled as temperature 40℃±1℃, relative humidity 75%±2%RH, and storage in the dark; samples are taken at the beginning of the test (0 month), 3 months and 6 months respectively, and various stability indexes are detected; among them, the traditional hydrolat has obvious deterioration at 6 months, and only the 6-month data is recorded.

[0224] 2, detection index and method:

[0225] (1) appearance: the color difference value ΔE is measured by a color difference meter (model

CR-400

[0226] (2) odor: 5 professional aroma evaluators (with more than 5 years of experience in evaluating aromatic substances) use 10-point blind evaluation (10 points for the best, 0 points for complete deterioration), and take the average score;

[0227] (3) Precipitation: centrifuge the sample (3000 r / min, 10 min), collect the precipitate and weigh, calculate the percentage of the precipitate in the total mass of the sample;

[0228] (4) Retention rate of zedone: the content of zedone was detected by gas chromatograph (model

Agilent 7890A

[0229] 3. Test results: the stability of the hydrolat obtained by the preservation method of Example 2 of the present application and the stability of the hydrolat of the control group were tested according to the above detection indexes and methods, and the test results are shown in Table 13 below:

[0230]

[0231] Table 13

[0232] 4. Result analysis: as can be seen from Table 13, the hydrolat obtained by the preservation method of the present application only slightly yellowed (ΔE < 1.5) and had no precipitate after 6 months of accelerated testing; while the hydrolat preserved by the traditional method had obviously yellowed (ΔE > 5.0) and produced flocculent precipitate after 6 months, indicating that the color stability and uniformity of the hydrolat obtained by the preservation method of the present application were significantly better than those of the hydrolat obtained by the traditional method; the hydrolat obtained by the preservation method of the present application still had a mild woody aroma (8.5 points) after 6 months, while the hydrolat preserved by the traditional method had a rancid smell (4.0 points) after 6 months, indicating that the hydrolat obtained by the preservation method of the present application could effectively inhibit the deterioration of aroma; the hydrolat obtained by the preservation method of the present application only contained a small amount of suspended matter (< 0.1%) after 6 months, while the traditional hydrolat produced a large amount of precipitate (> 2.0%), indicating that the system stability of the hydrolat obtained by the preservation method of the present application was better; the retention rate of zedone in the hydrolat obtained by the preservation method of the present application was 95.7% ± 2.1% after 6 months, which was much higher than that of the traditional hydrolat (72.3% ± 3.8%), indicating that the effective ingredient was more stable.

[0233] (II) Test the preservative performance of the hydrolat

[0234] 1. Group setting: the prepared rhizoma scirpi hydrolat was evenly divided into multiple test groups, each test group had different concentrations of preservatives, and a blank control group was set up without adding any preservatives.

[0235] 2. Preservative addition: different concentrations of preservatives were added to the rhizoma scirpi hydrolat in each test group according to the predetermined concentration gradient, then 1 ml of the ethanol solution was added to every 100 ml of the hydrolat, and stirring was performed to ensure that the preservatives were fully dispersed in the hydrolat.

[0236] 3. Microbial challenge test: A certain amount of common microorganisms (total bacterial count CFU / g <1000, fecal coliforms not detectable, Pseudomonas aeruginosa not detectable, Staphylococcus aureus not detectable, molds and yeasts CFU / g <100) were inoculated into the hydrosol samples of each test group and control group to simulate the microbial contamination that may occur during actual use. The inoculated samples were placed in an environment suitable for microbial growth and the growth of microorganisms was observed regularly.

[0237] 4. Indicator Testing

[0238] Antibacterial effect: At different time points, the number of microorganisms in each test group and control group was determined using the plate count method or other suitable microbial detection methods, and the logarithmic decrease value of microorganisms was calculated. 10 Reduction) = log 10 (colony count in control group) - log 10 (colony count in test group). This indicator can directly reflect the actual order of magnitude of microbial killing (e.g., a 3Log decrease = killing 99.9% of microorganisms), and dynamically monitor the changes in sterilization effect at different time points (7 / 14 / 28 days).

[0239] The inhibitory effects of different preservatives on microorganisms were evaluated by comparing the microbial growth inhibition rates of different test groups, as shown in Tables 14-16 below:

[0240] Test Group 1

[0241]

[0242] Table 14

[0243] Test conclusion: As shown in Table 14, the combination of preservatives has a significant inhibitory effect on microorganisms within 7 days, with a logarithmic decrease value of more than 3.0, indicating that it can effectively kill more than 99.9% of microorganisms.

[0244] Test Group 2

[0245]

[0246] Table 15

[0247] Test conclusions: As shown in Table 15, increasing the concentration of some preservatives slightly enhanced the antibacterial effect, and the logarithmic decrease value remained above 3.2, indicating that the combination has a stable and effective inhibitory effect on microorganisms.

[0248] Test Group 3

[0249]

[0250] Table 16

[0251] Test Conclusion: As can be seen from Table 16, further increasing the concentration of some preservatives can further enhance the bacteriostatic effect, especially the concentration of octanohydroxamic acid significantly improves the logarithmic reduction value to 3.8, indicating that the preservative combination has better inhibition effect on microorganisms at a higher concentration.

[0252] In summary, by using the "logarithmic reduction value (Log 10 Reduction)" to quantify the bacteriostatic effect, the inhibition ability of different preservative combinations and concentrations on microorganisms can be clearly seen, which provides a strong basis for selecting the optimal preservative combination. The reasons for selecting 1,2-hexanediol and p-hydroxyacetophenone as the preservative combination are as follows: strong bacteriostatic effect, synergistic effect, simplified formula, reduced potential risks, low irritation, and high safety, etc. The combination of 1,2-hexanediol and p-hydroxyacetophenone is the preferred solution for the preservation of rockrose hydrolate, which can effectively extend the shelf life of the product while ensuring the safety and user experience of the product. The combination of 1,2-hexanediol and p-hydroxyacetophenone exhibits high-efficiency synergistic bacteriostatic properties (logarithmic reduction value > 3.0 within 7 days), safety of a simplified formula (only 2 ingredients reduce the risk of allergies), and dual mild properties (both are certified by international cosmetic regulations).

[0253] Based on the above examples and test results, the extraction method of the present application is based on microwave-assisted steam distillation, combined with raw material pretreatment, by studying the effects of different rockrose powder to water mass ratios, microwave treatment power, microwave extraction time, and extraction temperature on essential oil yield, the optimal extraction conditions are determined, making the rockrose essential oil yield exceed 2%, the content of vetiverol in vetiver oil can be increased to 75.69%, and the purity reaches 920.39 μg / g, while the essential oil yield of traditional steam distillation is about 0.67%, not more than 1%, significantly improving the extraction efficiency, product quality, and storage stability of rockrose essential oil and hydrolate, reducing production cost and extraction time, and being very suitable for industrial or industrial production and application.

[0254] The above examples are preferred embodiments of the present application, but the embodiments of the present application are not limited by the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application are equivalent replacement methods, and are included in the protection scope of the present application.

Claims

1. A method for extracting essential oil and hydrosol from vetiver roots, characterized in that: The extraction method includes the following steps: Step 1) Raw material pretreatment: Cut the roots of one-year-old vetiver harvested at the jointing stage into 4-6cm root segments, rinse them repeatedly with distilled water or tap water, and dry them until the moisture content is ≤12%. After air drying, the root segments are mechanically crushed in a pulverizer at a rate of ≤200g / batch. After crushing, the vetiver powder is obtained by sieving through a sieve with a mesh size of 60-100. The processed vetiver powder is stored at ≤-20℃. Step 2) Weighing: Weigh the pretreated vetiver powder; Step 3) Mixing the material and liquid: Place the vetiver powder in a microwave reactor and add distilled water at a mass-to-volume ratio of 1:8 to 1:15 to form a mixed material and liquid; Step 4) Microwave treatment: Place the flask containing the mixture of vetiver powder and water into a microwave device for microwave treatment. The power of the microwave treatment is 450W-700W and the microwave treatment time is 4min-6min. Step 5) Steam distillation: Transfer the microwave-treated raw material directly to the steam distillation apparatus. Start steam distillation within 5 minutes after the microwave treatment ends. Control the steam distillation temperature at 95–99℃ and the distillation extraction time at 2.5–3.5 hours. Monitor the pressure simultaneously and maintain it at ≤0.1MPa. Step 6) Separation of essential oil and hydrosol: After distillation, once no water droplets flow out of the condenser, use a cooling water circulator to circulate and cool the condenser. Add an effective amount of salt reagent to the oil-water mixture in the receiving bottle, let the receiving bottle stand, and allow the oil-water mixture in the receiving bottle to separate into layers. Collect the upper layer of essential oil and the lower layer of hydrosol separately. Dry and filter the collected essential oil to obtain the final essential oil product.

2. The method for extracting vetiver root essential oil and hydrosol according to claim 1, characterized in that: In step 1), the drying is carried out in any of the following ways: (a) Store in a cool, well-ventilated place away from light and dry; (b) Dry under air conditioning for 20-40 minutes.

3. The method for extracting vetiver root essential oil and hydrosol according to claim 1, characterized in that: In step 4), the microwave equipment used in the microwave processing is a microwave oven.

4. The method for extracting vetiver root essential oil and hydrosol according to claim 2, characterized in that: In step 5), the steam distillation device is a volatile oil extractor, and the steam distillation device needs to be sterilized with steam before distillation.

5. The method for extracting vetiver root essential oil and hydrosol according to claim 1, characterized in that: In step 5), zeolite is added to the distillation flask of the volatile oil extractor, with the amount of zeolite added being 0.5–1% of the raw material mass.

6. The method for extracting vetiver root essential oil and hydrosol according to claim 1, characterized in that: In step 6), the added salt reagent is sodium chloride, and the effective amount of salt reagent added is to make the sodium chloride concentration in the oil-water mixture reach 0.5% to 5% (w / v), and the receiving bottle is left to stand for 40 min to 80 min.

7. The method for extracting vetiver root essential oil and hydrosol according to claim 2, characterized in that: In step 6), the separation process of essential oil and hydrosol includes: Step 61) Use a separatory funnel to separate the oil layer and the water layer. Dry the separated oil layer by adding a desiccant to the oil layer and mixing the desiccant with the essential oil. Place the mixture in a sealed container and shake vigorously for at least 2 hours. After shaking, filter out the desiccant and impurities through a filter device to obtain the vetiver essential oil product. Step 62) Collect the separated water layer to obtain vetiver hydrosol.

8. The method for extracting vetiver root essential oil and hydrosol according to claim 7, characterized in that: The desiccant is anhydrous sodium sulfate, and the amount of anhydrous sodium sulfate added is 10%-20% of the weight of the essential oil. The filtration device is a filter paper or glass fiber filter.

9. A method for preserving hydrosol from vetiver roots, characterized in that: The storage method includes the following process: Step S1) Heat the hydrosol obtained from the vetiver root to 85±2℃ and keep it warm for 8-12 minutes, then cool it to 25-30℃; Step S2) Add a preservative to the cooled hydrosol; add 0.8-3 wt% of 1,2-hexanediol to the hydrosol cooled to room temperature, then heat the hydrosol to 65 degrees Celsius and add 0.3-1.0 wt% of p-hydroxyacetophenone at this temperature. Step S3) Seal the final hydrosol product obtained in step S2) in an amber glass bottle and store it in a light-protected environment at ≤15℃.

10. The method for preserving vetiver root hydrosol according to claim 9, characterized in that: In step S2), 1,2-hexanediol is added at a concentration of 1 wt% after the hydrosol is cooled to room temperature, and p-hydroxyacetophenone is added at a concentration of 0.5 wt% when the hydrosol is heated to 65 degrees Celsius.

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