Method for extracting torreya grandis aril essential oil by combining enzymolysis with subcritical solvent extraction method

Abstract

The invention provides a method for extracting torreya grandis aril essential oil by combining enzymolysis with a subcritical solvent extraction method, and belongs to the technical field of plant extraction.The method comprises the following steps that S1, fresh torreya grandis aril is pulped to obtain pulp; s2, adding a compound enzyme solution into the slurry obtained in the S1, and performing enzymolysis at 25-35 DEG C for 2-4 hours to obtain an enzymolysis product; s3, freezing and slicing the enzymolysis product obtained in the step S2 by using a freezing and slicing machine to obtain a sliced sample, putting the sliced sample into a centrifugal tube, adding a modified oxalic acid hollow inclusion compound which accounts for 0.3-0.5% of the mass of the sliced sample, transferring the centrifugal tube into a freezing and grinding instrument, and grinding to obtain ground powder; and S4, carrying out subcritical butane extraction on the ground powder obtained in S3 to obtain the torreya grandis aril essential oil. According to the invention, the solvent can more uniformly and effectively permeate and extract the essential oil component, so that the extraction rate of the essential oil component is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of plant extraction, and particularly relates to a method for extracting Torreya grandis aril essential oil by combining enzymolysis with subcritical solvent extraction. BACKGROUND

[0002] Torreya grandis is a unique and precious economic dry fruit tree species in China, mainly distributed in Zhejiang, Jiangsu, Anhui, Fujian and Jiangxi, and Shaoxing City in Zhejiang Province is the main producing area of Torreya grandis, known as the "Hometown of Chinese Torreya grandis". The fruit of Torreya grandis is composed of aril, testa and edible seed kernel, and the aril of Torreya grandis is a layer of flesh structure wrapped outside the Torreya grandis fruit, accounting for 50%-60% of the mass of fresh fruit. At present, the utilization rate of Torreya grandis aril is low, and it is usually discarded as waste, which pollutes the environment and causes waste of resources. However, Torreya grandis aril is rich in volatile oil, lignan, flavonoids, Torreya grandis ester, terpenes and other active substances, and has biological activities such as antioxidant, antibacterial and anti-inflammatory, antitussive and insect repellent, and medicinal functions, which is a natural raw material for extracting medicinal active essential oil and spice products.

[0003] Low-temperature subcritical extraction technology is a new type of extraction and separation technology, and the whole extraction process is carried out under low temperature and low pressure conditions, which can maximize the retention of heat-sensitive functional ingredients in natural products; at the same time, through the selection of extraction solvent, the efficient and accurate extraction link of substances is realized. At present, low-temperature subcritical process has been applied to food, medicine and other fields. The combination of Torreya grandis aril and subcritical extraction technology has important significance for the development and utilization of Torreya grandis aril.

[0004] In the prior art, before subcritical extraction of Torreya grandis aril, the Torreya grandis aril is usually shredded, the purpose is to increase the contact area with the extraction agent, which helps the extraction agent to uniformly and effectively penetrate the plant cells, so as to improve the extraction efficiency. However, the simple shredding treatment method has very limited improvement on the extraction efficiency, and there is still a lot of room for improvement. SUMMARY

[0005] In order to solve the problems in the background art, the application provides a method for extracting Torreya grandis aril essential oil by combining enzymolysis with subcritical solvent extraction, which can ensure that the solvent can more uniformly and effectively penetrate and extract essential oil components, and further improve the extraction rate of essential oil components.

[0006] In order to achieve the above purpose, the technical scheme of the application is as follows:

[0007] A method for extracting Torreya grandis aril essential oil by combining enzymolysis with subcritical solvent extraction, comprising the following steps:

[0008] S1, beating fresh Torreya grandis aril to obtain pulp;

[0009] S2, adding a complex enzyme solution to the slurry obtained in S1, and performing enzymolysis at 25-35 DEG C for 2-4 h to obtain an enzymolysis product;

[0010] S3, performing frozen section processing on the enzymolysis product obtained in S2 using a frozen section machine to obtain a section sample, placing the section sample into a centrifuge tube, adding 0.3-0.5% of modified oxalic acid hollow inclusion compound to the section sample, and then transferring the centrifuge tube to a cryogenic grinder to perform grinding to obtain a ground powder;

[0011] S4, performing subcritical butane extraction on the ground powder obtained in S3 to obtain the Torreya grandis seed coat essential oil.

[0012] Further, in S2, the complex enzyme solution is prepared by dissolving a mixture of pectinase, cellulase and hemicellulase in a phosphate buffer solution with pH = 5.

[0013] Further, in the complex enzyme solution, the hemicellulase and pectinase are each 100,000 u / g, and the cellulase is 50,000 u / g, and the addition amount of the complex enzyme solution is 0.2% of the slurry.

[0014] Further, in S3, the modified oxalic acid hollow inclusion compound is prepared as follows:

[0015] A1, weighing 40 g of 2-hydroxypropyl-β-cyclodextrin, placing it in a 1000 mL conical flask with a plug, adding 500 mL of distilled water and 0.4 g of a complex surface modifier, stirring and dissolving at room temperature to obtain a modified dextrin dissolution solution;

[0016] A2, adding 10 mL of oxalic acid dropwise to the modified dextrin dissolution solution obtained in A1, stirring at room temperature for 2.5 hours, then refrigerating at 2-5 DEG C for 24 hours, filtering after the precipitation is complete, and drying in a desiccator to obtain the modified oxalic acid hollow inclusion compound.

[0017] Further, the complex surface modifier is prepared as follows: mixing alkylphenol polyoxyethylene ether and succinic anhydride according to a mass ratio of 0.5-0.8:1, stirring at a speed of 100-120 r / min in a water bath at 40-55 DEG C for 1 h, and cooling to room temperature to obtain the complex surface modifier.

[0018] Further, the 2-hydroxypropyl-β-cyclodextrin is prepared as follows:

[0019] A11, dissolving 12 g of purified β-cyclodextrin in 100 mL of a 3% NaOH aqueous solution, slowly adding a mixed solution of 5.2 mL of propylene oxide and 80 mL of acetonitrile under the condition of an ice water bath at 2-5 DEG C and a stirring speed of 50-60 r / min, continuing the addition for 2 h, and then maintaining the reaction for 22 h to obtain a reaction solution;

[0020] A12, neutralize the reaction solution with 5 mol / L hydrochloric acid, then rotary evaporation to dryness at 45℃, then dissolve in 20 mL of N, N-dimethylformamide, suction filtration, remove NaCL, then pour the filtrate into 200 mL of acetone, stir vigorously, produce white precipitate, suction filtration, repeatedly wash the precipitate with acetone 3 times, get fluffy white powder, vacuum drying at 40℃ for 24h, get 2-hydroxypropyl-β-cyclodextrin.

[0021] Further, in A11, the preparation method of the purified β-cyclodextrin is as follows: dissolve 60g of β-cyclodextrin in 300mL of deionized water, heat to boiling, after the β-cyclodextrin is completely dissolved, hot suction filtration, then the filtrate is placed in 2-5℃ ice water bath, with a glass rod, rapid and vigorous stirring, make β-cyclodextrin crystallization, then suction filtration, get β-cyclodextrin crystal; repeat 3 times, finally put the obtained β-cyclodextrin crystal into a vacuum drying oven, dry at 45℃ for 24h, get purified β-cyclodextrin.

[0022] Further, in S4, the pressure of the subcritical butane extraction is 0.2-0.6Mpa, the temperature is 30-50℃, the extraction time is 30-120min, and the extraction times is 2-4 times.

[0023] Further, in the subcritical butane extraction, the mass ratio of the grinding powder used in each extraction to butane is 1:3-20.

[0024] The present application has the following beneficial effects:

[0025] 1, beating can release the oil components in the aril of Torreya grandis, prepare for the subsequent extraction process; using complex enzyme solution for enzymolysis can deeply damage the cell wall, so that the essential oil is more easily extracted; in the process of freezing and grinding, the enzymolysis product is first treated by a freezing slicer, and then ground to obtain grinding powder, which can refine the material and increase the surface area, which is beneficial to improve the extraction efficiency and increase the yield of essential oil.

[0026] The addition of modified oxalic acid hollow inclusion can form many and uniform pores and concave-convex structures on the grinding powder, further increase the specific surface area, and make butane more easily penetrate and extract essential oil components, thereby improving the extraction rate of essential oil components.

[0027] 2, in the components of the modified oxalic acid hollow inclusion, oxalic acid has strong coordination and corrosion, which can coordinate and corrode the enzymolysis product to form voids and concave-convex structures; 2-hydroxypropyl-β-cyclodextrin as a derivative of cyclodextrin has the characteristics of internal hydrophobic and external hydrophilic, its hydrophobic cavity can better embed oxalic acid molecules to form stable inclusion;

[0028] The addition of the composite surface modifier can form micelles or vesicles and other self-assembly structures in the aqueous solution. The presence of these structures helps to form a more ordered structure in the aqueous solution, and on the other hand, interacts with the hydrophobic cavity of 2-hydroxypropyl-beta-cyclodextrin, so that the cavity is partially opened to form a gap, thereby changing the inclusion behavior of 2-hydroxypropyl-beta-cyclodextrin, promoting the formation efficiency and structural stability of the oxalic acid inclusion complex of 2-hydroxypropyl-beta-cyclodextrin, and better forming a modified oxalic acid hollow inclusion complex with a hollow cage shape.

[0029] The hollow cage-shaped coating of 2-hydroxypropyl-beta-cyclodextrin on oxalic acid molecules enables it to form pores and concave-convex structures on the grinding powder in a multi-site manner, avoids the occurrence of concentrated local corrosion, and ensures that relatively uniformly distributed pores and concave-convex structures can be formed on the grinding powder. BRIEF DESCRIPTION OF DRAWINGS

[0030] Fig. 1 A quality comparison trend chart of the torreya grandis aril essential oil extracted from 500g of fresh torreya grandis aril for the examples 1-7 and the comparative examples 1-10 of the present application is shown in the figure.

[0031] Fig. 2 A yield comparison trend chart of the torreya grandis aril essential oil for the examples 1-7 and the comparative examples 1-10 of the present application is shown in the figure. DETAILED DESCRIPTION

[0032] The present application will be further described in detail below in combination with examples.

[0033] The raw materials of the examples and comparative examples of the present application are all ordinary commercially available, except for special instructions.

[0034] Example 1

[0035] A method for extracting torreya grandis aril essential oil by combining enzymatic hydrolysis with subcritical solvent extraction, comprising the following steps:

[0036] S1, pulp the 500g of fresh torreya grandis aril to obtain pulp.

[0037] S2, add a composite enzyme solution to the pulp obtained in S1, and hydrolyze at about 30℃ for 3h to obtain a hydrolysis product.

[0038] The composite enzyme solution is prepared by dissolving a mixture of pectinase, cellulase and hemicellulase in a phosphate buffer with pH=5. In the composite enzyme solution, the hemicellulase and pectinase are both 100,000u / g, and the cellulase is 50,000u / g. The addition amount of the composite enzyme solution is 0.2% of the pulp.

[0039] S3, using a freezing microtome to freeze section the enzymatic product obtained in S2 to obtain a section sample, placing the section sample into a centrifuge tube, adding 0.4% of the modified oxalic acid hollow inclusion compound to the section sample, and then transferring the centrifuge tube to a cryomill to grind, thereby obtaining a ground powder.

[0040] The preparation method of the modified oxalic acid hollow inclusion compound is as follows:

[0041] A1, 40g of 2-hydroxypropyl-β-cyclodextrin was weighed and placed in a 1000ml conical flask with a plug, 500ml of distilled water and 0.4g of a composite surface modifier were added, and the mixture was dissolved at room temperature with stirring to obtain a modified dextrin solution;

[0042] A2, 10ml of oxalic acid was added dropwise to the modified dextrin solution obtained in A1, and the mixture was stirred at room temperature for 2.5 hours, then refrigerated at 2-5°C for 24 hours, then filtered and dried in a desiccator to obtain a modified oxalic acid hollow inclusion compound.

[0043] The preparation method of 2-hydroxypropyl-β-cyclodextrin is as follows:

[0044] A11, 12g of purified β-cyclodextrin was dissolved in 100ml of 3% NaOH aqueous solution, and a mixed solution of 5.2ml of propylene oxide and 80ml of acetonitrile was slowly added dropwise under the condition of 2-5°C ice water bath and 50-60r / min stirring speed, and the reaction was continued for 22h after the dropwise addition was completed for 2h, to obtain a reaction solution;

[0045] A12, the reaction solution was neutralized with 5mol / L hydrochloric acid, then rotary evaporated to dryness at 45°C, dissolved in 20ml of N,N-dimethylformamide, filtered to remove NaCL, then poured into 200ml of acetone, stirred vigorously to produce white precipitate, filtered, and the precipitate was washed with acetone for 3 times to obtain fluffy white powder, which was dried at 40°C under vacuum for 24h to obtain 2-hydroxypropyl-β-cyclodextrin.

[0046] In A11, the preparation method of purified β-cyclodextrin is as follows: 60g of β-cyclodextrin was dissolved in 300ml of deionized water, heated to boiling, and then filtered under vacuum after the β-cyclodextrin was completely dissolved. The filtrate was placed in an ice water bath at 2-5°C and stirred rapidly with a glass rod to crystallize the β-cyclodextrin, which was then filtered to obtain β-cyclodextrin crystals. This process was repeated 3 times, and finally the obtained β-cyclodextrin crystals were placed in a vacuum drying oven and dried at 45°C for 24h to obtain purified β-cyclodextrin.

[0047] The preparation method of the composite surface modifier is as follows: the alkyl phenol polyoxyethylene ether and succinic anhydride are mixed according to a mass ratio of 0.6:1, stirred at a stirring speed of 110 r / min under water bath condition at about 50 ℃ for 1 h, and cooled to room temperature, to obtain the composite surface modifier.

[0048] S4, the grinding powder obtained in S3 is subjected to subcritical butane extraction, to obtain the Torreya grandis aril essential oil.

[0049] The pressure of the subcritical butane extraction is 0.4 MPa, the temperature is about 40 ℃, the extraction time is 80 min, and the extraction times are 3.

[0050] Example 2

[0051] The difference between the present example and Example 1 is only that, in S3, the enzyme hydrolysis product obtained in S2 is subjected to frozen sectioning treatment using a frozen sectioning machine, to obtain a sectioning sample, the sectioning sample is placed into a centrifugal tube, 0.3% of the modified oxalic acid hollow inclusion compound based on the mass of the sectioning sample is added, and then the centrifugal tube is transferred into a frozen grinder, to obtain the grinding powder.

[0052] Example 3

[0053] The difference between the present example and Example 1 is only that, in S3, the enzyme hydrolysis product obtained in S2 is subjected to frozen sectioning treatment using a frozen sectioning machine, to obtain a sectioning sample, the sectioning sample is placed into a centrifugal tube, 0.5% of the modified oxalic acid hollow inclusion compound based on the mass of the sectioning sample is added, and then the centrifugal tube is transferred into a frozen grinder, to obtain the grinding powder.

[0054] Example 4

[0055] The difference between the present example and Example 1 is only that, the preparation method of the composite surface modifier is as follows: the alkyl phenol polyoxyethylene ether and succinic anhydride are mixed according to a mass ratio of 0.5:1, stirred at a stirring speed of 100 r / min under water bath condition at about 50 ℃ for 1 h, and cooled to room temperature, to obtain the composite surface modifier.

[0056] Example 5

[0057] The difference between the present example and Example 1 is only that, the preparation method of the composite surface modifier is as follows: the alkyl phenol polyoxyethylene ether and succinic anhydride are mixed according to a mass ratio of 0.8:1, stirred at a stirring speed of 120 r / min under water bath condition at about 50 ℃ for 1 h, and cooled to room temperature, to obtain the composite surface modifier.

[0058] Example 6

[0059] The difference between this example and example 1 is only that S4, the obtained ground powder of S3 is subjected to subcritical butane extraction, to obtain the Torreya grandis seed coat essential oil.

[0060] The pressure of subcritical butane extraction is 0.2 Mpa, the temperature is about 35℃, the time of one extraction is 30 min, and the extraction times is 2. In the subcritical butane extraction, the mass ratio of the ground powder to butane used in one extraction is 1:3.

[0061] Example 7

[0062] The difference between this example and example 1 is only that S4, the obtained ground powder of S3 is subjected to subcritical butane extraction, to obtain the Torreya grandis seed coat essential oil.

[0063] The pressure of subcritical butane extraction is 0.6 Mpa, the temperature is about 45℃, the time of one extraction is 120 min, and the extraction times is 4. In the subcritical butane extraction, the mass ratio of the ground powder to butane used in one extraction is 1:20.

[0064] Comparative Example 1

[0065] The difference between this comparative example and example 1 is only that the composite enzyme solution is prepared by dissolving a mixture of hemicellulase and cellulase in a phosphate buffer solution with pH = 5. In the composite enzyme solution, the hemicellulase is 100,000 u / g, and the cellulase is 50,000 u / g. The added mass of the composite enzyme solution is 0.2% of the slurry.

[0066] Comparative Example 2

[0067] The difference between this comparative example and example 1 is only that the composite enzyme solution is prepared by dissolving a mixture of pectinase and cellulase in a phosphate buffer solution with pH = 5. In the composite enzyme solution, the pectinase is 100,000 u / g, and the cellulase is 50,000 u / g. The added mass of the composite enzyme solution is 0.2% of the slurry.

[0068] Comparative Example 3

[0069] The difference between this comparative example and example 1 is only that the composite enzyme solution is not used any more, and is replaced by a single enzyme solution which is prepared by dissolving cellulase in a phosphate buffer solution with pH = 5. In the single enzyme solution, the cellulase is 50,000 u / g. The added mass of the single enzyme solution is 0.2% of the slurry.

[0070] Comparative Example 4

[0071] The difference between this comparative example and example 1 is only that the composite enzyme solution is directly deleted, and the slurry is not subjected to enzymatic hydrolysis treatment.

[0072] Specifically, a method for extracting Chinese torreya aril essential oil by enzymatic hydrolysis combined with subcritical solvent extraction, comprising the following steps:

[0073] S1, pulp the fresh Chinese torreya aril to obtain a pulp.

[0074] S2, using a freezing microtome to process the pulp obtained in S1 to obtain a section sample, placing the section sample into a centrifuge tube, then adding 0.4% of the mass of the section sample of modified oxalic acid hollow inclusion, and then transferring the centrifuge tube to a cryogenic grinder to grind to obtain a ground powder.

[0075] S3, subcritical butane extraction of the ground powder obtained in S2 to obtain Chinese torreya aril essential oil.

[0076] The other process steps and parameters are the same as in Example 1.

[0077] Comparative Example 5

[0078] The difference between this comparative example and Example 1 is only that in the preparation of the composite surface modifier, succinic anhydride is deleted.

[0079] Specifically, the preparation method of the composite surface modifier is as follows: the alkylphenol polyoxyethylene ether is stirred at a stirring speed of 110 r / min for 1 h under water bath conditions at about 50℃, and then cooled to room temperature to obtain the composite surface modifier.

[0080] Comparative Example 6

[0081] The difference between this comparative example and Example 1 is only that in the preparation of the composite surface modifier, alkylphenol polyoxyethylene ether is deleted.

[0082] Specifically, the preparation method of the composite surface modifier is as follows: the alkylphenol polyoxyethylene ether is stirred at a stirring speed of 110 r / min for 1 h under water bath conditions at about 50℃, and then cooled to room temperature to obtain the composite surface modifier.

[0083] Comparative Example 7

[0084] The difference between this comparative example and Example 1 is only that in the preparation of the modified oxalic acid hollow inclusion, the composite surface modifier is deleted.

[0085] Specifically, the preparation method of the modified oxalic acid hollow inclusion is as follows:

[0086] A1, weigh 40g of 2-hydroxypropyl-β-cyclodextrin, place it in a 1000mL conical flask with a plug, add 500mL of distilled water, stir and dissolve at room temperature to obtain a modified dextrin solution;

[0087] A2, 10 mL of oxalic acid was added dropwise to the modified dextrin solution obtained in A1, stirred at room temperature for 2.5 hours, then refrigerated at 2-5℃ for 24 hours, until the precipitation was complete, filtered, and dried in a desiccator to obtain the modified oxalic acid hollow inclusion compound.

[0088] Comparative Example 8

[0089] The difference between this comparative example and Example 1 is that in the preparation of the modified oxalic acid hollow inclusion compound, 2-hydroxypropyl-β-cyclodextrin is replaced by β-cyclodextrin.

[0090] Specifically, the preparation method of the modified oxalic acid hollow inclusion compound is as follows:

[0091] A1, 40 g of β-cyclodextrin was weighed and placed in a 1000 mL conical flask with a plug, 500 mL of distilled water and 0.4 g of a composite surface modifier were added, stirred and dissolved at room temperature to obtain a modified dextrin solution;

[0092] A2, 10 mL of oxalic acid was added dropwise to the modified dextrin solution obtained in A1, stirred at room temperature for 2.5 hours, then refrigerated at 2-5℃ for 24 hours, until the precipitation was complete, filtered, and dried in a desiccator to obtain the modified oxalic acid hollow inclusion compound.

[0093] Comparative Example 9

[0094] The difference between this comparative example and Example 1 is that the modified oxalic acid hollow inclusion compound is replaced by oxalic acid.

[0095] Specifically, a method for extracting Torreya grandis aril essential oil by enzymatic combination and subcritical solvent extraction method, comprising the following steps:

[0096] S1, fresh Torreya grandis aril was pulped to obtain a pulp.

[0097] S2, a composite enzyme solution was added to the pulp obtained in S1, and enzymatic hydrolysis was carried out at about 30℃ for 3h to obtain an enzymatic hydrolysate.

[0098] S3, the enzymatic hydrolysate obtained in S2 was subjected to frozen sectioning treatment using a frozen sectioning machine to obtain a sectioning sample, the sectioning sample was placed into a centrifuge tube, 0.4% oxalic acid based on the mass of the sectioning sample was added, and then the centrifuge tube was transferred to a cryogenic grinder for grinding to obtain a ground powder.

[0099] S4, the ground powder obtained in S3 was subjected to subcritical butane extraction to obtain Torreya grandis aril essential oil.

[0100] Comparative Example 10

[0101] The difference between this comparative example and Example 1 is that the modified oxalic acid hollow inclusion compound is deleted.

[0102] Specifically, the method for extracting Chinese torreya aril essential oil by enzymatic hydrolysis combined with subcritical solvent extraction comprises the following steps:

[0103] S1, fresh Chinese torreya aril is pulped to obtain pulp.

[0104] S2, a composite enzyme solution is added to the pulp obtained in S1, and enzymatic hydrolysis is carried out at about 30°C for 3h to obtain an enzymatic hydrolysate.

[0105] S3, the enzymatic hydrolysate obtained in S2 is subjected to frozen sectioning treatment using a frozen sectioning machine to obtain a sectioned sample, the sectioned sample is placed in a centrifuge tube, and then the centrifuge tube is transferred to a frozen grinder for grinding to obtain a ground powder.

[0106] S4, the ground powder obtained in S3 is subjected to subcritical butane extraction to obtain Chinese torreya aril essential oil.

[0107] Test example

[0108] In order to ensure the reliability of the comparison of test data, fresh Chinese torreya aril is uniformly pulped, and 500g of the same batch of pulp is directly taken for subsequent operation in Examples 1-7 and Comparative Examples 1-9, the mass of the finally prepared Chinese torreya aril essential oil is weighed, and the yield is calculated, and the statistical results are shown in Table 1.

[0109] Table 1. Yield of Chinese torreya aril essential oil in Examples 1-7 and Comparative Examples 1-9

[0110]

[0111] Result analysis: analyze Examples 1-7 and Comparative Example 1-10 and combine Table 1 data and Figs. 1-2 It can be seen that the enzymatic hydrolysis treatment of the composite enzyme solution on the Chinese torreya aril pulp can improve the yield of the Chinese torreya aril essential oil;

[0112] In the preparation of the composite enzyme solution, pectinase, cellulase and hemicellulase synergistically act, and any one of them is indispensable, and the absence of any one of them will lead to a decrease in the improvement effect on the yield of the Chinese torreya aril essential oil.

[0113] In the frozen grinding of the enzymatic hydrolysate to prepare powder, the addition of modified oxalic acid hollow inclusion can significantly improve the yield of the Chinese torreya aril essential oil;

[0114] In the preparation of the modified oxalic acid hollow inclusion, the use of 2-hydroxypropyl-β-cyclodextrin is better than the use of β-cyclodextrin, and the inventors guess that it may be because the 2-hydroxypropyl-β-cyclodextrin has a more uniform texture for coating oxalic acid, which is conducive to the formation of more uniform voids in size and position on the subsequent coating layer;

[0115] In the preparation of the modified oxalic acid hollow inclusion, the use of the composite surface modifier is essential. If the composite surface modifier is deleted, the yield of the Torreya grandis seed coat essential oil is greatly reduced, which is almost the same as that of the Torreya grandis seed coat essential oil after the direct deletion of the modified oxalic acid hollow inclusion. The inventors speculate that this may be because 2-hydroxypropyl-beta-cyclodextrin can form a uniform and dense outer coating layer on oxalic acid. If the composite surface modifier is not added, no pores will appear on the outer coating layer, and oxalic acid cannot directly act on the outer surface of the Torreya grandis seed coat particles, and cannot increase the specific surface area thereof.

[0116] In the preparation of the composite surface modifier, the alkylphenol polyoxyethylene ether and succinic anhydride synergistically act together to improve the yield of the Torreya grandis seed coat essential oil.

[0117] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present application will not further describe various possible combinations.

[0118] Furthermore, various different embodiments of the present application can also be combined in any manner, as long as they do not deviate from the spirit of the present application, and they should also be considered as disclosed by the present application.

Claims

1. A method for extracting essential oil from Torreya grandis aril using an enzymatic hydrolysis combined with subcritical solvent extraction, characterized in that, Includes the following steps: S1. Pulp fresh Torreya grandis arils to obtain pulp; S2. Add the compound enzyme solution to the slurry obtained in S1, and enzymatically hydrolyze it at 25-35℃ for 2-4 hours to obtain the enzymatic hydrolysis product. S3. Use a cryostat to cryo-slice the enzymatic hydrolysis product obtained in S2 to obtain sliced ​​samples. Place the sliced ​​samples into centrifuge tubes and add 0.3%-0.5% of the modified oxalic acid hollow inclusion complex by weight of the sliced ​​samples. Then transfer the centrifuge tubes to a cryo-grinder for grinding to obtain ground powder. S4. The ground powder obtained in S3 is subjected to subcritical butane extraction to obtain Torreya aril essential oil.

2. The method for extracting Torreya grandis aril essential oil according to claim 1, characterized in that, In S2, the complex enzyme solution is prepared by dissolving a mixture of pectinase, cellulase and hemicellulase in a phosphate buffer solution at pH 5.

3. The method for extracting Torreya grandis aril essential oil according to claim 2, characterized in that, In the compound enzyme solution, both hemicellulase and pectinase are 100,000 u / g, and cellulase is 50,000 u / g. The added mass of the compound enzyme solution is 0.2% of the slurry.

4. The method for extracting Torreya grandis aril essential oil according to claim 1, characterized in that, In S3, the preparation method of the modified oxalic acid hollow inclusion complex is as follows: A1. Weigh 40g of 2-hydroxypropyl-β-cyclodextrin and place it in a 1000mL stoppered conical flask. Add 500mL of distilled water and 0.4g of composite surface modifier. Stir and dissolve at room temperature to obtain modified dextrin solution. A2. Add 10 mL of oxalic acid to the modified dextrin solution obtained in A1, stir at room temperature for 2.5 hours, then refrigerate at 2-5℃ for 24 hours until precipitation is complete, filter, and dry in a desiccator to obtain the modified oxalic acid hollow inclusion complex.

5. The method for extracting Torreya grandis aril essential oil according to claim 4, characterized in that, The composite surface modifier is prepared as follows: alkylphenol polyoxyethylene ether and succinic anhydride are mixed at a mass ratio of 0.5-0.8:1, stirred at a stirring speed of 100-120 r / min for 1 h under water bath conditions of 40-55℃, and cooled to room temperature to obtain the composite surface modifier.

6. The method for extracting Torreya grandis aril essential oil according to claim 4 or 5 using enzymatic hydrolysis combined with subcritical solvent extraction, characterized in that, The preparation method of the 2-hydroxypropyl-β-cyclodextrin is as follows: A11. Dissolve 12g of purified β-cyclodextrin in 100mL of 3% NaOH aqueous solution. Under the conditions of ice-water bath at 2-5℃ and stirring speed of 50-60r / min, slowly add 5.2mL of propylene oxide and 80mL of acetonitrile solution. The addition is completed in 2h. Continue to react for 22h to obtain the reaction solution. A12. Neutralize the reaction solution with 5 mol / L hydrochloric acid, then evaporate to dryness at 45℃. Dissolve the solution in 20 mL of N,N-dimethylformamide, filter to remove NaCl, and then pour the filtrate into 200 mL of acetone. Stir vigorously to produce a white precipitate. Filter the precipitate and wash it three times with acetone to obtain a fluffy white powder. Dry the powder under vacuum at 40℃ for 24 h to obtain 2-hydroxypropyl-β-cyclodextrin.

7. The method for extracting Torreya grandis aril essential oil according to claim 6, characterized in that, In A11, the method for preparing purified β-cyclodextrin is as follows: Dissolve 60g of β-cyclodextrin in 300mL of deionized water, heat to boiling, and after the β-cyclodextrin is completely dissolved, filter while hot. Then place the filtrate in an ice-water bath at 2-5℃ and stir rapidly and vigorously with a glass rod to allow β-cyclodextrin to crystallize out. Filter again to obtain β-cyclodextrin crystals. Repeat this process 3 times. Finally, place the obtained β-cyclodextrin crystals in a vacuum drying oven and dry at 45℃ for 24h to obtain purified β-cyclodextrin.

8. The method for extracting Torreya grandis aril essential oil according to claim 1, characterized in that, In S4, the subcritical butane extraction pressure is 0.2-0.6 MPa, the temperature is 30-50℃, the extraction time is 30-120 min, and the number of extractions is 2-4.

9. The method for extracting Torreya grandis aril essential oil according to claim 1 or 8 using enzymatic hydrolysis combined with subcritical solvent extraction, characterized in that, In the subcritical butane extraction, the mass ratio of the grinding powder to butane used in one extraction is 1:3-20.

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