Method for synchronously extracting pectin and essential oil

Abstract

The invention provides a synchronous extraction method of pectin and essential oil, belongs to the field of plant extraction, and can solve the technical problems that a traditional extraction method of pectin and essential oil generally needs multi-step extraction, the steps are tedious, and strong mineral acid is used. The method comprises the following steps: firstly, adding a shaddock peel residue raw material into a first extraction solution for pretreatment, and then directly adding the pretreated raw material solution into a second extraction solution for microwave treatment to prepare the shaddock peel essential oil, and meanwhile, removing precipitates separated out by combining the first extraction solution and the second extraction solution, adding a proper amount of absolute ethyl alcohol into the obtained supernate, and carrying out a post-treatment process to obtain the pectin. According to the method, a brand new extraction system is constructed, and pectinase is directly added into the extraction system to ensure that pectinase is not passivated or inactivated, so that two target extracts do not need to be performed step by step, the process steps are simplified, and one-step extraction of pectin and essential oil is realized. The method can be applied to one-step extraction of pectin and essential oil.

Description

Technical Field

[0001] The present application belongs to the field of plant extraction, and relates to a deep processing technology of fruit peel residue byproducts, and in particular to a method for simultaneous extraction of pectin and essential oil. Background Art

[0002] During the growth of Shatian pomelo, due to the limited carrying capacity of pomelo trees, farmers must selectively screen and remove young fruits in densely growing areas to improve the quality of the fruit later in the season. However, many functional components of these discarded young pomelo fruits are abandoned; the quality of the young fruit peel accounts for about 50% of the total mass of the fruit, rich in soluble pectin and a large amount of essential oil. The treatment of the removed young pomelo fruits can lead to problems such as environmental pollution and waste of plant resources. Therefore, the rational use of discarded young pomelo fruits is of great scientific significance for environmental protection and resource recycling.

[0003] Essential oil extracted from pomelo peel is often used in important fields such as agricultural antibacterial, aromatherapy in daily life, medical treatment, and health care. The oil contains monoterpenes, sesquiterpenoids and their oxygenated derivatives, which have antioxidant, antibacterial and anti-inflammatory activities. Pectin is a complex heteropolysaccharide rich in galacturonic acid that acts as an adhesive in plant cells. It has stabilizing, gelling and thickening properties, as well as anticancer effects and the effect of lowering serum cholesterol and blood sugar levels.

[0004] In the prior art, pectin and essential oils are usually extracted in multiple steps, generally including: first cutting the peel into small pieces for enzymatic hydrolysis, then using diluted strong mineral acid for vacuum distillation to obtain essential oils, and finally vacuum concentrating the supernatant to obtain pectin. The above extraction method has the following problems: on the one hand, the extraction of pectin by hot extraction with diluted strong mineral acid (hydrochloric acid or sulfuric acid) is still easy to corrode equipment even when used at a diluted concentration, causing environmental pollution and potential harm to consumers' health; on the other hand, the extraction steps are cumbersome and the operation is complicated.

[0005] Therefore, how to provide a one-step method for extracting pectin and essential oil simultaneously while avoiding the use of strong mineral acids is the key to solving the above problems. Summary of the invention

[0006] In view of the technical problems of the above-mentioned traditional pectin and essential oil extraction methods which usually require multi-step extraction, have complicated steps, and use strong mineral acids, this application proposes a simultaneous extraction method of pectin and essential oils, which can achieve a one-step extraction of pectin and essential oils. This method has the characteristics of high extraction rate and simple operation, and also avoids the use of strong mineral acids.

[0007] In order to achieve the above purpose, the technical solution adopted in this application is: A method for synchronously extracting pectin and essential oil comprises the following steps: Firstly, the pomelo peel residue raw material is added to a first extraction solution for pretreatment, and then the pretreated raw material solution is directly added to a second extraction solution for microwave treatment to obtain pomelo peel essential oil; At the same time, the precipitate formed by combining the first extraction solution and the second extraction solution is removed, and an appropriate amount of anhydrous ethanol is added to the obtained supernatant, and then pectin is obtained through a post-treatment process.

[0008] In one embodiment, the first extraction solution is an acidic quaternary ammonium salt solution, and the second extraction solution is an inorganic salt aqueous solution.

[0009] In one embodiment, the addition ratio of the acidic quaternary ammonium salt solution to the inorganic salt aqueous solution is 1:(1-5).

[0010] In one embodiment, the acidic quaternary ammonium salt solution is prepared by the following method: A certain proportion of natural organic acid and quaternary ammonium salt are heated to form a solution, and the pH value thereof is adjusted to 2-8 to obtain the acidic quaternary ammonium salt solution; The heating treatment is carried out at 50-100° C. for 5-60 min, preferably 20-40 min.

[0011] In one embodiment, the natural organic acid is selected from any one of citric acid, malic acid, sorbic acid or ascorbic acid, and the quaternary ammonium salt is selected from choline chloride or hexadecyldimethylbenzyl ammonium.

[0012] In one embodiment, pectinase is added during the pretreatment process, and the pretreated raw material solution is obtained after enzymatic hydrolysis at 55° C.-65° C. for 1-6 hours.

[0013] In one embodiment, the microwave treatment is microwave-assisted water distillation treatment.

[0014] In one embodiment, the post-processing step is: Add an appropriate amount of anhydrous ethanol to the obtained supernatant and perform high-speed homogenization to obtain a suspension; The suspension is stored in a low temperature environment for 12 hours to 48 hours, the supernatant is filtered out, and the precipitate is dried to obtain the pectin.

[0015] In one embodiment, the pomelo peel residue raw material is prepared from young pomelo fruits.

[0016] Compared with the prior art, the advantages and positive effects of this application are: 1. The present application provides a method for the simultaneous extraction of pectin and essential oils, by constructing an extraction system of "acidic quaternary ammonium salt solution-inorganic salt aqueous solution" and directly incorporating pectinase into the extraction system to ensure that it is not passivated or inactivated, so that the two target extracts do not need to be carried out step by step, simplifying the operation steps, and realizing a one-step extraction of pectin and essential oils; 2. The present application provides a method for the simultaneous extraction of pectin and essential oils, wherein an acidic quaternary ammonium salt solution is prepared by combining a natural organic acid with a quaternary ammonium salt solution, thereby avoiding the use of strong mineral acids, not easily causing equipment corrosion and environmental pollution, and not causing harm to the health of consumers; 3. The present application provides a method for the simultaneous extraction of pectin and essential oils, which uses young pomelo fruits as the extraction object, which can not only improve the extraction rate of pectin and essential oils, but also reasonably utilize the discarded young pomelo fruits to achieve the recycling and reuse of waste fruit resources; 4. The present application provides a method for the simultaneous extraction of pectin and essential oil. The pectin extraction rate of the method can reach up to 26.70±1.35%, and the essential oil extraction rate can reach up to 2.09±0.11%. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The pH screening test results of the acidic quaternary ammonium salt solution provided in the examples of the present application; Figure 2 A graph showing the relationship between the microwave irradiation power, the solid-liquid ratio, the pH of the acidic quaternary ammonium salt solution and the yields of the two target extracts provided in the examples of the present application; Figure 3 Schematic diagram of materials at different extraction stages provided in the embodiments of the present application. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0019] The present application embodiment provides a method for simultaneous extraction of pectin and essential oil, comprising the following steps: Firstly, the pomelo peel residue raw material is added to a first extraction solution for pretreatment, and then the pretreated raw material solution is directly added to a second extraction solution for microwave treatment to obtain pomelo peel essential oil; At the same time, the precipitate formed by combining the first extraction solution and the second extraction solution is removed, and an appropriate amount of anhydrous ethanol is added to the obtained supernatant, and then pectin is obtained through a post-treatment process.

[0020] The above embodiment provides a method for extracting pectin and essential oils, which is a "one-step" extraction method, wherein the first extraction solution used is an acidic quaternary ammonium salt solution, and the second extraction solution is an inorganic salt aqueous solution, wherein the acidic quaternary ammonium salt solution is prepared by heating a natural organic acid and a quaternary ammonium salt, and then adjusting the pH thereof to 2-8. In order to achieve the one-step extraction of pectin and essential oils, the present application is mainly based on the following collaborative improvements: (1) Selection of a suitable extraction system: On the one hand, the present application selects an acidic quaternary ammonium salt solution as the first extraction solution, and the pH of the extraction solution is 2-8, preferably 2-6. Under the extraction conditions, not only can the hydrolysis reaction of pectin molecules under excessively high pH conditions be avoided, which is beneficial to maintaining the stability of pectin and thus ensuring its extraction rate, but also pectinase can be directly incorporated into the extraction system, that is, the grapefruit peel residue raw material is added to the first extraction solution and an appropriate amount of pectinase is added for pretreatment. The acidic quaternary ammonium salt system has a certain protective effect on pectin. The acidic quaternary ammonium salt solution system will have a certain protective effect on pectinase, maintain the stability of the enzyme protein, and then the pectinase can still maintain its activity in the extraction system without causing passivation or inactivation, thereby affecting its enzymatic effect on the grapefruit peel raw material. The extraction method provided by the present application can enable pectinase to directly participate in the extraction process of pectin and essential oil, without the need to cut the grapefruit peel raw material into small pieces for enzymatic pretreatment and then perform strong mineral acid extraction as in the traditional extraction method. It can be seen that the present application can not only ensure the extraction rate of pectin and essential oil by optimizing the extraction system, but also directly incorporate pectinase into the extraction system, avoiding the enzymatic pretreatment process, simplifying the extraction process, and having strong operability. In addition, it should be supplemented that the present application adds pectinase to the acidic quaternary ammonium salt solution for the pretreatment process, specifically, after enzymatic hydrolysis at 55°C-65°C for 1h-6h, a pretreated raw material solution is obtained.

[0021] Among them, the above-mentioned enzymatic hydrolysis temperature can be specifically selected from 55°C, 56°C, 57°C, 58°C, 59°C, 60°C, 61°C, 62°C, 63°C, 64°C, 65°C or any value within the above range according to actual needs by those skilled in the art, and appropriate fine-tuning based on the above temperature range does not depart from the technical concept of the present application, and all fall within the protection scope of the present application; the enzymatic hydrolysis time can be specifically selected from 1h, 2h, 3h, 4h, 5h, 6h or any value within the above range according to actual needs by those skilled in the art, and appropriate fine-tuning based on the above time range does not depart from the technical concept of the present application, and all fall within the protection scope of the present application.

[0022] On the other hand, the present application adds the raw material solution after pretreatment into the second extraction solution for microwave-assisted water distillation to obtain grapefruit peel essential oil (at this time, pectin is retained in the raw material solution). The present application selects an inorganic salt aqueous solution as the second extraction solution, and the extraction solution mainly plays the following roles: 1) used to dilute the acidic quaternary ammonium salt solution; 2) the inorganic salt aqueous solution will reduce the boiling point during the heating process; 3) auxiliary extraction: during the process of soaking the plant raw material in the quaternary ammonium salt solution after dilution with the inorganic salt solution, it helps to destroy the plant cell wall, increase the outflow of the contents, help the material to be extracted more fully, and further improve the extraction rate of essential oil and pectin; 4) will not destroy the stability of pectin retained in the raw material solution; 5) the solution diluted with the inorganic salt aqueous solution is beneficial to protect the raw material during the heating process.

[0023] (2) Define the order of adding the two extraction solutions; The present application selects an acidic quaternary ammonium salt solution as the first extraction solution to be used first, and an inorganic salt solution is selected as the second extraction solution to be used after microwave extraction, and the order of use of the two extraction solutions cannot be changed. Once the order is changed (i.e., the inorganic salt solution is used as the first extraction solution first, and the acidic quaternary ammonium salt solution is used as the second extraction solution to be used after microwave extraction), in this case, if pectinase is used together with the inorganic salt solution, pectin extraction cannot be achieved because the pH does not reach an acidic environment. If pectinase is added to the acidic quaternary ammonium salt solution and microwave heating is performed together, it is very easy to cause enzyme inactivation, which will cause the raw material to be unable to be enzymolyzed, and ultimately, the purpose of simultaneous extraction of pectin and essential oils cannot be achieved. In addition, the grapefruit peel residue needs to be pre-enzymolyzed in an acidic quaternary ammonium salt solution, and the enzymolysis solution before being diluted by the inorganic salt solution has a higher concentration, and the enzymolysis effect is better. In addition, if the order of the two extraction solvents is reversed, pectinase will be inactivated, thereby reducing the extraction rate of pectin and essential oils by 20%.

[0024] It can be seen that the present application selects an acidic quaternary ammonium salt solution as the first extraction solution and uses it together with pectinase. This enzymolysis condition will not cause enzyme inactivation, but is also beneficial to pectin extraction, does not affect the stability of pectin, and then uses an inorganic salt solution for dilution and microwave-assisted water distillation to extract essential oils. At the same time, the diluted solution in this process is beneficial to protecting the raw materials during the heating process. By optimizing the extraction system and limiting the order of use of the two extraction solvents and the timing of adding pectinase, a one-step extraction of pectin and essential oils is achieved, simplifying the extraction steps.

[0025] Furthermore, in the extraction method of the present application, the addition ratio between the above-mentioned acidic quaternary ammonium salt solution and the inorganic salt aqueous solution is 1: (1-5), preferably 1: 5. The acidic quaternary ammonium salt solution is specifically prepared by the following method: A certain proportion of natural organic acid and quaternary ammonium salt are heated to form a solution, and the pH value is adjusted to 2-8, preferably 2-6, to obtain the acidic quaternary ammonium salt solution; wherein the heating treatment condition is 50-100° C. for 5-60 min, preferably 20-40 min.

[0026] In the above preparation method, the natural organic acid used in the preparation of the acidic quaternary ammonium salt solution is selected from any one of citric acid, malic acid, sorbic acid or ascorbic acid, and the quaternary ammonium salt is selected from choline chloride or hexadecyl dimethyl benzyl ammonium. In some other embodiments, the natural organic acid in the acidic quaternary ammonium salt solution can also be other types of natural organic acids selected by those skilled in the art according to actual needs. The pH of the acidic quaternary ammonium salt solution is preferably 2-6, and can specifically be selected from 2, 3, 4, 5, 6, 7, 8, or any numerical value within the above range according to actual needs by those skilled in the art, and appropriate fine-tuning based on the above pH range does not deviate from the technical concept of the present application, and all fall within the scope of protection of the present application. The above heating temperature can specifically be selected from 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, or any numerical value within the above range according to actual needs by those skilled in the art, and appropriate fine-tuning based on the above temperature range does not deviate from the technical concept of the present application, and all fall within the scope of protection of the present application. The above-mentioned heating time can be specifically selected from 5min, 10min, 15min, 20min, 25min, 30min, 35min, 40min, 45min, 50min, 55min, 60min or any value within the above range according to actual needs by technical personnel in this field, and appropriate fine-tuning based on the above-mentioned heating time range does not depart from the technical concept of the present application and falls within the protection scope of the present application.

[0027] Next, an inorganic salt aqueous solution is prepared by the following method: An inorganic salt aqueous solution of a certain concentration is prepared using an inorganic metal salt and used as a diluent for the acidic quaternary ammonium salt solution.

[0028] Wherein, the inorganic metal salt selected in the above-mentioned inorganic salt aqueous solution preparation method includes but is not limited to any one of sodium chloride, magnesium chloride or lithium chloride. In some other embodiments, those skilled in the art can also select other types of quaternary ammonium salts according to actual needs without departing from the technical concept of the present application and falling within the protection scope of the present application. It should be noted that the inorganic metal salt that will not affect pectin and essential oil should be selected for solution preparation.

[0029] In a specific embodiment, the post-processing step mentioned in the above-mentioned method for simultaneous extraction of pectin and essential oil specifically refers to: S1, removing the precipitate formed by combining the first extraction solution and the second extraction solution, adding an appropriate amount of anhydrous ethanol to the obtained supernatant, and performing high-speed homogenization to obtain a suspension; Based on the above step S1, at the same time, under the microwave heating environment, the acidic quaternary ammonium salt solution and the inorganic salt aqueous solution are combined to precipitate a large amount of precipitation, the precipitate is filtered to remove the precipitate, and an appropriate amount of anhydrous ethanol is added to the supernatant, and high-speed homogenization is performed to obtain a suspension. Among them, the amount of anhydrous ethanol added is not limited here, and the technology in the field can be added according to actual needs, and the specific amount added can be flexibly adjusted.

[0030] S2. Store the suspension in a low temperature environment for 12 h to 48 h, filter out the supernatant, and obtain pectin by drying the precipitate.

[0031] In the above step S2, low temperature storage refers to storage at 5°C, and the specific storage temperature can also be flexibly adjusted according to actual needs. The above drying treatment can be carried out by conventional methods.

[0032] The grapefruit peel residue raw material mentioned in the aforementioned simultaneous extraction method of pectin and essential oil is prepared from young pomelo fruits, and the processing method can be carried out by conventional methods. On the one hand, the pectin and essential oil content in the young pomelo fruits is very rich, which can improve the extraction rate of the material, and can also reasonably utilize the discarded young pomelo fruits to realize the recycling and reuse of waste fruit resources.

[0033] In some other embodiments, the pomelo peel residue raw material used in the simultaneous extraction method of pectin and essential oil provided in the present application can also be prepared from other types of pomelo fruits, and is also applicable to other types of pomelo fruits.

[0034] In order to more clearly and in detail introduce a method for simultaneous extraction of pectin and essential oil provided in the embodiments of the present application, it will be described below in conjunction with specific embodiments.

[0035] Embodiment 1: This embodiment provides a method for simultaneous extraction of pectin and essential oil, comprising the following steps: First, young pomelo fruits are processed into pomelo peel residue raw materials, and then the pomelo peel residue raw materials are added to an acidic quaternary ammonium salt solution and an appropriate amount of pectinase is added for pretreatment (after enzymolysis at 60° C. for 3 hours), and then the pretreated raw material solution is directly added to an inorganic salt aqueous solution for microwave heating-assisted water distillation to obtain pomelo peel essential oil; wherein the pH of the acidic quaternary ammonium salt solution is 2, and the addition ratio of the acidic quaternary ammonium salt solution to the inorganic salt aqueous solution is 1:5; At the same time, under the microwave heating environment, a large amount of precipitate is precipitated from the combination of the acidic quaternary ammonium salt solution and the inorganic salt aqueous solution. The precipitate is filtered out, and an appropriate amount of anhydrous ethanol is added to the supernatant, and high-speed homogenization is performed to obtain a suspension, which is stored in an environment of 5°C for 48 hours, and the supernatant is filtered out to obtain the precipitate, which is then dried to obtain pectin.

[0036] Embodiment 2: This embodiment provides a pH screening test for an acidic quaternary ammonium salt solution, specifically: The present application adopts the method shown in Example 1 for simultaneous extraction of pectin and essential oil, the only difference being that the pH of the acidic quaternary ammonium salt solution is set to 2, 3, 4, 5, 6, and 7, respectively, and the simultaneous extraction of pectin and essential oil is performed, and the extraction rates of the obtained pectin and essential oil are measured. The measurement results are shown in Figure 1 .

[0037] Result analysis: Figure 1 As shown, the blue column represents the extraction rate of essential oil, the yellow column represents the extraction rate of pectin, and the horizontal axis represents the pH size of acidic quaternary ammonium salt solution. As can be seen from the figure: the extraction rate of pectin will gradually decrease with the increase of pH, and the reason for this phenomenon may be because: the acidic environment is conducive to maintaining the stability of pectin, and the pectin molecule will undergo hydrolysis under the too high pH value. It is dissolved in the solvent, and then causes the pectin yield to reduce. However, the extraction rate of essential oil will increase with the increase of pH, and therefore, in order to seek that both essential oil and pectin extraction rates can maintain relatively ideal extraction rates, it is very important to control the pH of acidic quaternary ammonium salt solution within a reasonable range. In the synchronous extraction method provided by the application, the pH of acidic quaternary ammonium salt solution is selected 2-8 and is preferably 2-6, and the extraction rate of two materials is the best when pH is 2.

[0038] Embodiment 3: In order to further improve the extraction rate of pectin and essential oil, this embodiment explores the relationship between the combination of microwave irradiation power, microwave treatment time, solid-liquid ratio and solution pH on the extraction rate of pectin and essential oil, as follows: The above-mentioned solid-liquid ratio refers to the ratio of the acidic quaternary ammonium salt solution diluted with an inorganic salt aqueous solution as the raw material to the acidic quaternary ammonium salt solution diluted with an inorganic salt aqueous solution as the solvent; the solution pH refers to the solution of the acidic quaternary ammonium salt solution diluted with an inorganic salt aqueous solution.

[0039] The extraction method shown in Example 1 was adopted, and the microwave irradiation power, the solid-liquid ratio and the solution pH were respectively limited. The specific conditions were as follows: Microwave irradiation power: 140 W, 420 W, 700 W; Microwave treatment time: 30min, 50min, 70min; Material-liquid ratio: 4:1, 5:1, 6:1; Solution pH: 3.25, 4.5, 5.75; This example specifically analyzes the effects of microwave irradiation power, microwave treatment time, solid-liquid ratio and solution pH on the yield of essential oil (see Figure 2 -abc), and the effects of microwave irradiation power, microwave treatment time, solid-liquid ratio and solution pH on pectin yield (see Figure 2 -def).

[0040] like Figure 2 As shown, based on the above experiments, multiple factors including microwave irradiation power, microwave treatment time, solid-liquid ratio and solution pH will affect the yields of essential oil and pectin. By setting the liquid-to-solid ratio at 4 mL / g, the solution pH at 5.75, the microwave irradiation power at 560 W, and the microwave irradiation time at 30 min, the simultaneous extraction of pectin and essential oil was performed with reference to the method shown in Example 1, and finally the pectin yield was 28.10% and the essential oil yield was 2.01%.

[0041] also, Figure 3 The comparison of material status at different extraction stages is shown, among which, Figure 3 -A is the powder residue after the pomelo peel is crushed before extraction (i.e., the pomelo peel residue raw material); Figure 3 -B is the dried residue after essential oil is extracted with an acidic deep eutectic solvent using microwave assistance; Figure 3 -C is dried pectin.

Claims

1. A method for synchronous extraction of pectin and essential oil, characterized in that: The following steps are involved: Firstly, the pomelo peel residue raw material is added to a first extraction solution for pretreatment, and then the pretreated raw material solution is directly added to a second extraction solution for microwave treatment to obtain pomelo peel essential oil; At the same time, the precipitate formed by combining the first extraction solution and the second extraction solution is removed, and an appropriate amount of anhydrous ethanol is added to the obtained supernatant, and then pectin is obtained through a post-treatment process.

2. The method for synchronously extracting pectin and essential oil according to claim 1, characterized in that: The first extraction solution is an acidic quaternary ammonium salt solution, and the second extraction solution is an inorganic salt aqueous solution.

3. The synchronous extraction method of pectin and essential oil according to claim 2, characterized in that, The addition ratio of the acidic quaternary ammonium salt solution to the inorganic salt aqueous solution is 1:(1-5).

4. The synchronous extraction method of pectin and essential oil according to claim 2, characterized in that, The acidic quaternary ammonium salt solution is prepared by the following method: A certain proportion of natural organic acid and quaternary ammonium salt are heated to form a solution, and the pH value thereof is adjusted to 2-8 to obtain the acidic quaternary ammonium salt solution; Wherein, the heating treatment condition is heating at 50-100°C for 5-60min.

5. The method for synchronous extraction of pectin and essential oil according to claim 4, characterized in that: The natural organic acid is selected from any one of citric acid, malic acid, sorbic acid or ascorbic acid, and the quaternary ammonium salt is selected from choline chloride or hexadecyl dimethyl benzyl ammonium.

6. The method for synchronous extraction of pectin and essential oil according to claim 4, characterized in that: The pH of the acidic quaternary ammonium salt solution is 2-6.

7. The method for synchronous extraction of pectin and essential oil according to claim 1, characterized in that: During the pretreatment process, pectinase is added simultaneously, and after enzymolysis at 55° C.-65° C. for 1-6 hours, the pretreated raw material solution is obtained.

8. The method for simultaneous extraction of pectin and essential oil according to claim 1, characterized in that: The microwave treatment is microwave-assisted water distillation treatment.

9. The method for synchronous extraction of pectin and essential oil according to claim 1, characterized in that: The post-processing steps are: Add an appropriate amount of anhydrous ethanol to the obtained supernatant and perform high-speed homogenization to obtain a suspension; The suspension is stored in a low temperature environment for 12 hours to 48 hours, the supernatant is filtered out, and the precipitate is dried to obtain the pectin.

10. The method for simultaneous extraction of pectin and essential oil according to any one of claims 1 to 9, characterized in that: The pomelo peel residue raw material is prepared from young pomelo fruits.

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