Method for removing pesticide residues in ginger extract

Abstract

The invention discloses a method for removing pesticide residues in a ginger extract, and belongs to the technical field of ginger extract refining. The method comprises the following steps: adding water into a ginger extract raw material to fully disperse the ginger extract raw material, then adding alkali to adjust pH, and carrying out hydrolysis and neutralization reaction to obtain feed liquid I; adding a calcium chloride solution into the feed liquid I to react to generate a precipitate, and separating to obtain a precipitate; adding an acid solution into the precipitate to carry out acidolysis reaction, then standing for layering, and separating to obtain a lower-layer feed liquid I; adding a surfactant into the lower-layer feed liquid I for emulsifying, then standing for layering, and separating to obtain lower-layer feed liquid II; and performing dehydration treatment on the lower-layer feed liquid II to obtain the refined ginger extract. The method solves the problem that pesticide residues in the ginger extract exceed the standard. The method is green, safe, simple to operate and low in cost, can be effectively applied to large-scale production, and can be used for separating gingerol from pesticide residues to the greatest extent to prepare the clean and safe ginger extract meeting the standard.

Description

Technical Field

[0001] The present invention belongs to the technical field of ginger extract refinement, and particularly relates to a method for removing pesticide residues in ginger extracts. Background Art

[0002] Ginger is the fresh rhizome of a perennial herbaceous plant of the Zingiberaceae family and the Zingiber genus. Ginger is warm in nature, and its unique "gingerol" can stimulate the gastrointestinal mucosa, causing hyperemia in the gastrointestinal tract and enhancing digestive ability, and can effectively treat abdominal distension, abdominal pain, diarrhea, vomiting, etc. caused by excessive consumption of cold foods. Gingerol, as a general term for a class of compounds related to pungency extracted from ginger, mainly includes components such as gingerol, shogaol, and zingerone. These compounds endow ginger with its unique pungency and various biological activities.

[0003] The specific effects of gingerol include:

[0004] Antioxidant and anti-inflammatory effects: Gingerol has significant antioxidant ability, can inhibit the release of inflammatory factors, and can be used for anti-inflammatory and anti-tumor purposes.

[0005] Promote metabolism: Gingerol can stimulate blood circulation, increase the metabolic rate, help burn fat, and is often used in weight loss and fat reduction products.

[0006] Antibacterial and antifungal effects: Gingerol has an inhibitory effect on a variety of bacteria and fungi, and can be used in antibacterial and antifungal drugs.

[0007] Relieve arthritis: Research shows that gingerol can significantly reduce the pain of arthritis patients, and the effect is comparable to ibuprofen.

[0008] Promote digestion: Gingerol can shorten the residence time of proteins in the stomach and improve the absorption efficiency of proteins.

[0009] Other effects: Gingerol also has the effects of relieving motion sickness, preventing gastric ulcers, and improving cardiovascular function.

[0010] Currently, the extraction methods of ginger extracts mainly include steam distillation method, solvent extraction method, ultrasonic method, supercritical carbon dioxide extraction method, and pressing method; at present, the supercritical carbon dioxide extraction technology is relatively mature, and during the supercritical carbon dioxide extraction process, the extraction temperature is low, and the yields of ginger essential oil and ginger oleoresin (the active ingredient is gingerol) in the extraction process are ideal, which is very suitable for large-scale ginger raw material processing and industrial production.

[0011] However, currently, in order to maximize the yield of ginger, the planting area is usually fumigated with excessive pesticides before planting to prevent insect infestation and virus infection. During the planting process, pesticides need to be sprayed intermittently to prevent pests and ensure the healthy growth of ginger seedlings. After harvesting, a large amount of pesticides need to be sprayed during the storage process for antibacterial and pest control. This leads to the problem of excessive pesticide residues in the produced ginger. When extracting through supercritical carbon dioxide extraction, some pesticide residues in the ginger raw materials will migrate to the ginger extract products, and the types of pesticide residues are complex, with diverse properties and excessive doses. The main types of pesticide residues include organophosphorus pesticide residues, organochlorine pesticide residues, etc. Therefore, pesticide residues have become one of the main factors restricting the application of ginger extracts in food.

[0012] The maximum residue limits of pesticides in ginger in China mainly follow the national food safety standard "GB 2763-2021" Maximum Residue Limits of Pesticides in Foods. The food category to which ginger belongs is "root and tuber vegetables", and there are a total of 70 maximum residue limit standards for pesticides involved. These standards stipulate the maximum allowable residue amounts of different pesticides in ginger to ensure food safety.

[0013] The European Union classifies ginger as "root spices" in "spices", and its pesticide residue limit standards are more strict and detailed. There are a total of 470 maximum residue limit standards for ginger pesticides in the EU standards. These standards cover more types of pesticides and set strict maximum values for the residue amounts of each pesticide.

[0014] Currently, among the related preparation technologies for removing pesticide residues, there is one that involves using supercritical carbon dioxide extraction technology for separation. For example, Chinese patent CN116474415A uses the solvent extraction method to extract ginger oleoresin with excessive pesticide residues as the raw material, uses ginger essential oil as the entrainer, and undergoes refining treatment in a supercritical carbon dioxide extraction kettle. The total content of pesticide residues in the refined ginger oleoresin obtained by this patent is between 3-5 ppm, and there are individual cases of excessive pesticide residues, which cannot fully meet the EU standards.

[0015] Therefore, further research is needed on the problem of removing pesticide residues from ginger extracts. Summary of the Invention

[0016] The purpose of the present invention is to overcome at least one deficiency of the prior art and provide a method for removing pesticide residues from ginger extracts and the ginger extracts prepared by the method.

[0017] The technical solution adopted by this application is:

[0018] A method for removing pesticide residues from ginger extracts, comprising the following steps:

[0019] (1) Add water to the ginger extract raw material to fully disperse it, then add an alkali to adjust the pH, and carry out hydrolysis and neutralization reactions to obtain the first liquid material;

[0020] (2) Add a calcium chloride solution to the first liquid material to react and form a precipitate, and separate to obtain the precipitate;

[0021] (3) Add an acid solution to the precipitate to carry out an acidolysis reaction, then let it stand for layering, and separate to obtain the lower-layer first liquid material;

[0022] (4) Add a surfactant to the lower-layer first liquid material for emulsification, then let it stand for layering, and separate to obtain the lower-layer second liquid material;

[0023] (5) Carry out dehydration treatment on the lower-layer second liquid material to obtain the ginger extract.

[0024] In some embodiments, in step (1), the mass-volume ratio of the ginger extract raw material to water is 1:(2 - 5) g / mL.

[0025] In some embodiments, in step (1), the alkali is one or both of sodium hydroxide or potassium hydroxide, and / or, add an alkali to adjust the pH value to 12 - 13.

[0026] In some embodiments, in step (1), the reaction temperature of the hydrolysis and neutralization reactions is 20 - 30 °C, and the reaction time is ≤30 min to reduce the content loss of gingerol.

[0027] In some embodiments, in step (2), the mass percentage concentration of the calcium chloride solution is 20 - 50%; and / or; the mass-volume ratio of the ginger extract raw material to the calcium chloride solution is 1:(1 - 3) g / mL.

[0028] In some embodiments, in step (2), the reaction temperature for adding the calcium chloride solution to react is 20 - 40 °C, and the reaction time is 0.2 - 1 h.

[0029] In some embodiments, in step (2), the separation of the precipitate is carried out by filtration or centrifugation; preferably, filter after standing for 20 - 40 min to separate the precipitate; and / or; the precipitate also includes the step of rinsing with an alkali solution with a pH of 12 - 13.

[0030] In some embodiments, in step (3), the conditions of the acidolysis reaction include any one of a) - e):

[0031] a) The mass-volume ratio of the ginger extract raw material to the acid solution is 1:(2 - 5) g / mL; and / or;

[0032] b) The pH of the acid solution is 1 - 2, and / or;

[0033] c) The temperature of the acidolysis reaction is 25 - 55 °C, preferably 30 - 50 °C; and / or;

[0034] d) The time of the acidolysis reaction is 1 - 3 h; and / or;

[0035] e) After the acidolysis reaction is completed, add alkali to adjust the pH to 4 - 6, and then let it stand for layering.

[0036] In some of the embodiments, in step (4), the surfactant is polyoxyethylene sorbitan fatty acid ester, including at least one of polyoxyethylene sorbitan monolaurate (Tween 20), polyoxyethylene sorbitan monopalmitate (Tween 40), and polyoxyethylene sorbitan monooleate (Tween 80), and / or, the mass - volume fraction (w / V) of the surfactant is 2 - 5%; and / or, the mass - volume ratio of the raw ginger extract material to the surfactant solution is 1:(2 - 5) g / mL, and the separation is carried out 2 - 5 times.

[0037] In some of the embodiments, in step (5), the dehydration treatment is vacuum concentration dehydration treatment, and the conditions of the vacuum concentration dehydration treatment are: dehydration temperature 55 °C - 70 °C, vacuum degree - 0.06 MPa to - 0.1 MPa, dehydration time 1 - 3 h.

[0038] A ginger extract is prepared by the method described in any one of the above.

[0039] The beneficial effects of this application are:

[0040] This application provides a method for removing pesticide residues in ginger extract, solving the problem of excessive pesticide residues in ginger extract products. The method is green, safe, simple to operate, and low - cost, and can be effectively applied to large - scale production. It can separate gingerol and pesticide residues to the greatest extent, and prepare a ginger extract product that meets the standards, is clean, and safe. Description of the Drawings

[0041] Figure 1 For the raw ginger extract material (left) and the refined ginger extract (right).

[0042] Figure 2 For the liquid chromatogram of the determination of gingerol content in the refined ginger extract. It mainly includes five components: 6 - gingerol, 8 - gingerol, 6 - gingerenol, 10 - gingerol, and 8 - gingerenol. The detection method follows "GB / T 22293 - 2008 Determination of the Main Stimulating Components in Ginger and Its Oleoresin - HPLC Method". Detailed Embodiments

[0043] The preferred embodiments of the present invention will be described in detail below in conjunction with the embodiments. It should be understood that the following embodiments are given only for illustrative purposes and are not used to limit the scope of the present invention. Those skilled in the art can make various modifications and substitutions to the present invention without departing from the purpose and spirit of the present invention.

[0044] Unless otherwise specified, the experimental methods used in the following embodiments are all conventional methods. The materials, reagents, etc. used in the following embodiments can be obtained from commercial sources or prepared by conventional methods in the art unless otherwise specified.

[0045] The term "removal" means reducing to a very low level, but does not necessarily mean "completely absent". The removal of pesticide residues in ginger extract as described in this application means reducing the pesticide residues in ginger extract to a very low level.

[0046] In some of the embodiments, ginger extract produced by supercritical carbon dioxide extraction method is used as the raw material, and after being further refined by the method of this application, refined ginger extract is obtained. The content of gingerol in the refined ginger extract obtained in this application generally exceeds 50 mg / g, while the general requirement for the content of gingerol in related gingerol products is generally 5% or 5 mg / g. After the refined ginger extract is further prepared into a gingerol product in the form of powder or liquid with a content of 5% or 5 mg / g, the pesticide residue content of the gingerol product meets the strict standards of the European Union.

[0047] The embodiment of this application provides a method for removing pesticide residues in ginger extract. The method is simple to operate and has low production cost, and can be used for large-scale industrial production. This method is of great significance for facilitating the export of ginger products in our country abroad and can enhance the overall competitiveness of our country's agriculture.

[0048] A method for removing pesticide residues in ginger extract includes the following steps:

[0049] (1) Add water to the ginger extract raw material to make it fully dispersed, then add alkali to adjust the pH, and carry out hydrolysis and neutralization reactions to obtain the first material liquid;

[0050] (2) Add calcium chloride solution to the first material liquid to react to form a precipitate, and separate to obtain the precipitate;

[0051] (3) Add acid solution to the precipitate to carry out acidolysis reaction, then let it stand for stratification, and separate to obtain the lower first material liquid;

[0052] (4) Add surfactant to the lower first material liquid for emulsification, then let it stand for stratification, and separate to obtain the lower second material liquid;

[0053] (5) Dehydrate the lower layer of liquid material II to obtain the ginger extract.

[0054] In some of these embodiments, the raw material ginger extract is the so-called ginger oleoresin, also known as oleoresin ginger, or ginger extract, with the foreign name Giger oleoresin. Ginger oleoresin is a dark brown or reddish-brown viscous liquid extracted from ginger. It has the pungency and aroma of ginger and is a mixture containing various chemical components. It mainly contains gingerol and some volatile oils, and the chemical substances therein include ginger alcohol, zingiberene, borneol, citral, eucalyptol ether, as well as special spicy substances such as gingerol, gingerenol, and gingerone.

[0055] The extraction process of ginger oleoresin usually uses supercritical CO2 extraction. This process can efficiently extract gingerol and retain the characteristic aroma and flavor of ginger. Ginger oleoresin is generally a reddish-brown oily liquid, with a strong characteristic aroma and pungency of ginger and is insoluble in water.

[0056] In some of these embodiments, the raw material of the ginger extract contains 20 - 60 mg / g of gingerol and less than 2 ml / 100 g of ginger essential oil.

[0057] The detection method of gingerol includes high performance liquid chromatography (HPLC). Using high performance liquid chromatography (HPLC) to determine the content of gingerol is mainly to determine the content of more than 10 gingerol compounds such as 6-gingerol, 8-gingerol, and 10-gingerol in ginger and its processed products or extracts, and add up the contents of these compounds to obtain the total content of gingerol. Generally, the content of 6-gingerol in gingerol is the highest.

[0058] In some of these embodiments, in step (1), the mass-volume ratio of the raw material ginger extract to water is 1:(2 - 5) g / mL.

[0059] In some of these embodiments, in step (1), add water to the raw material ginger extract and promote the full dispersion of the ginger extract by stirring.

[0060] In some of these embodiments, in step (1), the alkali is one or both of sodium hydroxide or potassium hydroxide, and the pH value is adjusted to 12 - 13.

[0061] In some of these embodiments, in step (1), the reaction temperature of the hydrolysis and neutralization reaction is 20 - 30 °C, and the reaction time ≤ 30 min.

[0062] Since ginger extract (such as gingerol) has higher solubility under alkaline conditions, in step (1) of this application, water is added first to promote its preliminary dispersion, and then the pH is adjusted to 12 - 13 with an alkali to completely dissolve the ginger extract. The process of complete dissolution is a hydrolysis and neutralization reaction. Among them, the hydrolysis reaction is that the alkali reacts with the ester group in the resin to form sodium carboxylate, and the neutralization reaction is that the phenolic hydroxyl group in gingerol is acidic and can be neutralized to form sodium phenolate.

[0063] In some of these embodiments, in step (2), the mass percentage concentration of the calcium chloride solution is 20 - 50%; the mass - to - volume ratio of the ginger extract raw material to the calcium chloride solution is 1:(1 - 3) g / mL.

[0064] In some of these embodiments, in step (2), the reaction temperature for adding the calcium chloride solution is 20 - 40°C, and the reaction time is 0.2 - 1 h.

[0065] In this application, by adding a calcium chloride solution with a preferred concentration and volume in step (2), the active ingredient gingerol in the ginger extract forms calcium gingerolate and precipitates out, so as to separate from the pesticide residues in the ginger extract, achieving the purpose of removing pesticide residues. This step can remove most pesticide residues, including water - soluble and fat - soluble pesticide residues. Salts outside the scope of this application (such as a magnesium chloride solution with a mass percentage concentration of 30%) cannot achieve this effect.

[0066] In some of these embodiments, in step (2), the precipitate is separated by filtration or centrifugation, preferably by filtering after standing for 20 - 40 min to separate the precipitate.

[0067] In some of these embodiments, in step (2), the precipitate also includes the step of rinsing with an alkali solution with a pH of 12 - 13. The mass - to - volume ratio of the ginger extract raw material to the rinsing alkali solution is 1:(1 - 2) g / mL, and preferably rinsing is carried out 2 - 5 times. Rinsing with alkali water further precipitates the calcium gingerolate and dissolves the remaining pesticides in the alkali water for removal.

[0068] In some of these embodiments, in step (3), the conditions for the acidolysis reaction include any one of a) - e):

[0069] a) The mass - to - volume ratio of the ginger extract raw material to the acid solution is 1:(2 - 5) g / mL; and / or;

[0070] b) The pH of the acid solution is 1 - 2, and / or;

[0071] c) The temperature of the acidolysis reaction is 25 - 55°C, preferably 30 - 50°C; and / or;

[0072] d) The time of the acidolysis reaction is 1 - 3 h; and / or;

[0073] e) After the acidolysis reaction is completed, add alkali to adjust the pH to 4 - 6, and then let it stand for layering.

[0074] In step (3), add acid to reform gingerol from calcium gingerolate, and separate it after layering with water.

[0075] In some embodiments, in step (4), the surfactant is polyoxyethylene sorbitan fatty acid ester, including at least one of polyoxyethylene sorbitan monolaurate (Tween 20), polyoxyethylene sorbitan monopalmitate (Tween 40), and polyoxyethylene sorbitan monooleate (Tween 80), and / or, the mass - volume fraction of the surfactant is 2 - 5%; and / or, the mass - volume ratio of the raw ginger extract to the surfactant solution is 1:(2 - 5) g / mL, and preferably separate 2 - 5 times.

[0076] In some embodiments, in step (4), the temperature for the emulsification reaction with the addition of the surfactant is 50 - 65 °C, and the time is 20 - 40 min.

[0077] In some embodiments, when adding the surfactant for emulsification, stirring is required during the emulsification reaction, and then let it stand for layering.

[0078] Adding the surfactant in step (4) further dissolves the residual pesticides in water for removal. The ginger extract layers with water under weakly acidic conditions, and still layers after reacting with the surfactant. At the same time, the surfactant can also carry away the residual pesticides (including fat - soluble pesticides and water - soluble pesticides), achieving the effect of further removing pesticides.

[0079] Due to the extremely high water solubility of Tween, during the standing and layering process after emulsification, it can completely dissolve in the water phase and separate out with the upper liquid phase, and will not remain in the final product.

[0080] In some embodiments, in step (5), the dehydration treatment is vacuum concentration dehydration treatment, and the conditions of the vacuum concentration dehydration treatment are: dehydration temperature 55 °C - 70 °C, vacuum degree - 0.06 MPa to - 0.1 MPa, and dehydration time 1 - 3 h.

[0081] Concentrating under reduced pressure at a suitable temperature can improve the concentration efficiency and shorten the concentration time.

[0082] A ginger extract is prepared by the method described in any one of the above. The ginger extract is a refined ginger extract after further removing pesticide residues. The refined ginger extract obtained in the examples of this application has low pesticide residues. After the refined ginger extract is further prepared into a gingerol product in the form of a powder or liquid with a content of 5% or 5 mg / g, the gingerol product can meet the EU standards and can be used in the fields of food, medicine, cosmetics, etc.

[0083] The following further illustrates the present application with reference to examples.

[0084] The raw material used in the examples of this application is a ginger extract, which is a ginger extract produced by the supercritical carbon dioxide extraction method, and more specifically refers to ginger oleoresin. The ginger oleoresin contains 20 - 60 mg / g of gingerol and less than 2 ml / 100 g of ginger essential oil.

[0085] The specific method is as follows: The dried ginger slices are crushed and then put into a supercritical carbon dioxide extraction kettle. The pressure of the extraction kettle is increased to 28 MPa, the temperature is maintained at 45 °C, the carbon dioxide flow rate is 8 L / h per kilogram of dried ginger raw material, the extraction time is 4 h, the pressure of separator 1 is 8 MPa, the temperature of separator 1 is 40 °C, the pressure of separator 2 is 5.5 Mpa, and the temperature in separator 2 is 35 °C. After treatment, ginger extract 1 is obtained in separator 1, and ginger essential oil is obtained in separator 2.

[0086] Therefore, the raw material of this application mainly refers to ginger extract 1 obtained from reactor 1 in the supercritical carbon dioxide extraction (see Figure 1 left). Ginger extract 1 mainly contains ginger oleoresin (the active ingredient is gingerol) and a very small amount of essential oil.

[0087] Through detection, the content of gingerol in ginger extract 1 is 51.50 mg / g, chlorpyrifos is 2.30 ppm, thiamethoxam is 4.15 ppm, imidacloprid is 2.46 ppm, fosthiazate is 3.72 ppm, metalaxyl is 4.76 ppm, carbendazim is 8.25 ppm, and clothianidin is 3.16 ppm.

[0088] In the examples of this application, chlorpyrifos, fosthiazate, and metalaxyl are detected with reference to GB 23200.113, thiamethoxam is detected with reference to GB23200.9, and imidacloprid and clothianidin are detected with reference to GB / T 20769.

[0089] In the research and development process of this application, experiments of different specifications (such as small-scale tests and pilot-scale tests) have been carried out. The labels of the examples do not represent the sequence of experiments in the research and development process.

[0090] The rotation speed of the stirring in the examples is 100 - 500 rpm, and those skilled in the art can adjust it according to the size of the equipment.

[0091] The following examples are used to illustrate the present invention, but not to limit the scope of the present invention.

[0092] Example 1

[0093] This example provides a method for removing pesticide residues in ginger extract. This example uses ginger extract 1 as the raw material.

[0094] 1. Weigh 1.00 kg of ginger extract 1, add tap water with a volume 3 times that of the ginger extract (L), stir for 0.5 h to fully disperse the ginger extract, add sodium hydroxide solution, adjust the pH = 12.5, and stir and react at 25 °C for 10 min to obtain liquid material 1 after full mixing and reaction;

[0095] 2. Add calcium chloride solution with a volume 2 times that of the extract and a concentration of 30% to liquid material 1, stir and react at 30 °C for 0.5 h after adding, let it stand for 0.5 h and then filter to separate the precipitate, wash the precipitate with alkaline water with a volume 1 time that of the ginger extract and a pH = 12.5, repeat the washing 3 times in total to obtain precipitate 1;

[0096] 3. Put precipitate 1 into acidic water with a pH = 2 and a volume 3 times that of the extract, heat to 50 °C and stir for 2 h, adjust the pH = 6 with sodium hydroxide after full reaction, let it stand for 0.5 h and separate and collect the lower-layer liquid material;

[0097] 4. Add Tween 20 with a volume 2 times that of the ginger extract and a mass-volume fraction of 2% to the lower-layer liquid material, stir at 60 °C for 30 minutes, let it stand for 30 minutes to separate layers to obtain the lower-layer liquid material, and repeat this step 5 times in total;

[0098] 5. Concentrate and dehydrate the separated lower-layer liquid material under the conditions of a water bath temperature of 65 °C and a vacuum degree of -0.08 MPa for 1.5 - 2.5 h, stop concentrating when the water content of the lower-layer liquid material is less than 2% to obtain 0.95 kg of refined ginger extract (see Figure 1 right).

[0099] After detection, the gingerol content in this refined ginger extract is 52.24 mg / g, the total recovery rate of the total gingerol content is 96.37%, chlorpyrifos and imidacloprid are not detected (detection limit 0.1 ppm), thiamethoxam is 0.21 ppm, fosthiazate is 0.16 ppm, metalaxyl is 0.20 ppm, carbendazim is 0.42 ppm, and clothianidin is 0.12 ppm. After the refined ginger extract is further prepared into a gingerol product in the form of a powder or liquid with a content of 5%, the pesticide residues of the gingerol product meet the EU standards.

[0100] Figure 2It is a liquid chromatogram for detecting the content of gingerol in refined ginger extract, mainly including five components: 6-gingerol, 8-gingerol, 6-shogaol, 10-gingerol, and 8-shogaol.

[0101] Example 2

[0102] This example provides a method for removing pesticide residues in ginger extract. This example uses ginger extract 1 as the raw material.

[0103] 1. Weigh 1.00 kg of ginger extract 1, add tap water with a volume three times that of the ginger extract (L), stir for 0.5 h to fully disperse the ginger extract, add sodium hydroxide solution, adjust the pH = 12, and stir and react at 25 °C for 30 min to obtain liquid material 1 after sufficient mixing and reaction;

[0104] 2. Add a calcium chloride solution with a volume three times that of the extract and a concentration of 20% to liquid material 1. After adding, stir and react at 30 °C for 0.5 h, let it stand for 0.5 h, then filter and separate the precipitate. Wash the precipitate with alkaline water with a volume one time that of the ginger extract and a pH = 12, and repeat the washing 4 times in total to obtain precipitate 1;

[0105] 3. Put precipitate 1 into acidic water with a volume two times that of the extract and a pH = 1, heat to 50 °C and stir for 3 h. After sufficient reaction, add sodium hydroxide to adjust the pH = 6, let it stand for 0.5 h, and separate and collect the lower-layer liquid material;

[0106] 4. Add Tween 20 with a volume two times that of the ginger extract and a mass-volume fraction of 5% to the lower-layer liquid material, stir at 60 °C for 30 minutes, let it stand for 30 minutes to separate layers, and separate to obtain the lower-layer liquid material. Repeat this step 5 times in total;

[0107] 5. Concentrate and dehydrate the separated lower-layer liquid material under the conditions of a water bath temperature of 65 °C and a vacuum degree of -0.10 MPa for 1.5 - 2.5 h. Stop concentrating when the water content of the lower-layer liquid material is less than 2% to obtain 0.94 kg of refined ginger extract.

[0108] After detection, the content of gingerol in this refined ginger extract is 52.05 mg / g, the total recovery rate of gingerol is 95.00%, chlorpyrifos and imidacloprid are not detected (the detection limit is 0.1 ppm), thiamethoxam is 0.32 ppm, fosthiazate is 0.25 ppm, metalaxyl is 0.28 ppm, carbendazim is 0.41 ppm, and clothianidin is 0.16 ppm.

[0109] After the refined ginger extract is further prepared into a gingerol product in the form of a powder or liquid with a content of 5%, the pesticide residues in the gingerol product meet the EU standards.

[0110] Example 3

[0111] This embodiment provides a method for removing pesticide residues in ginger extract. This embodiment uses ginger extract 1 as the raw material.

[0112] 1. Weigh 1.00 kg of ginger extract 1, add tap water with a volume 3 times that of the ginger extract by weight (L), stir for 0.5 h to fully disperse the ginger extract, add sodium hydroxide solution, adjust the pH = 13, and stir and react at 25 °C for 10 min to obtain liquid material 1 through full mixing and reaction;

[0113] 2. Add a calcium chloride solution with a volume 1 time that of the extract and a concentration of 50% to liquid material 1. After adding, stir and react at 30 °C for 1 h, let it stand for 0.5 h, then filter and separate the precipitate. Wash the precipitate with alkaline water with a volume 1 time that of the ginger extract and a pH = 13, and repeat the washing 3 times in total to obtain precipitate 1;

[0114] 3. Put precipitate 1 into acidic water with a volume 5 times that of the extract and a pH = 1, heat to 50 °C and stir for 1 h. After full reaction, add sodium hydroxide to adjust the pH = 6, let it stand for 0.5 h to separate, and collect the lower-layer liquid material;

[0115] 4. Add Tween 20 with a volume 5 times that of the ginger extract and a mass-volume fraction of 2% to the lower-layer liquid material, stir at 60 °C for 30 minutes, let it stand for 30 minutes to separate layers, and obtain the lower-layer liquid material. Repeat this step 2 times in total for separation;

[0116] 5. Concentrate and dehydrate the separated lower-layer liquid material under the conditions of a water bath temperature of 70 °C and a vacuum degree of -0.06 MPa for 1.5 - 2.5 h. Stop concentrating when the water content of the lower-layer liquid material is less than 2% to obtain 0.93 kg of refined ginger extract.

[0117] After detection, the gingerol content in this refined ginger extract is 51.54 mg / g, the total recovery rate of gingerol is 93.07%, chlorpyrifos and imidacloprid are not detected (the detection limit is 0.1 ppm), thiamethoxam is 0.39 ppm, fosthiazate is 0.36 ppm, metalaxyl is 0.37 ppm, carbendazim is 0.57 ppm, and clothianidin is 0.26 ppm.

[0118] Example 4

[0119] This embodiment provides a method for removing pesticide residues in ginger extract. This embodiment uses ginger extract 1 as the raw material.

[0120] 1. Weigh 1.00 kg of ginger extract 1, add tap water with a volume 2 times that of the ginger extract by weight (L), stir for 0.5 h to fully disperse the ginger extract, add sodium hydroxide solution, adjust the pH = 12, and stir and react at 15 °C for 30 min to obtain liquid material 1 through full mixing and reaction;

[0121] 2. Add a calcium chloride solution with a volume 1 time that of the extract and a concentration of 50% to Liquid Material 1. After addition, stir and react at 40 °C for 1 h, let it stand for 0.5 h, then filter to separate the precipitate. Wash the precipitate with an alkaline solution with a volume 1 time that of the ginger extract and a pH of 12. Repeat the washing 3 times in total to obtain Precipitate 1.

[0122] 3. Put Precipitate 1 into an acidic solution with a volume 2 times that of the extract and a pH of 2, heat to 50 °C, stir for 3 h. After full reaction, adjust the pH to 5 with sodium hydroxide, let it stand for 0.5 h for separation, and collect the lower-layer liquid material.

[0123] 4. Add a volume 2 times that of the ginger extract and a 2% (mass / volume) Tween 80 to the lower-layer liquid material, stir at 60 °C for 30 minutes, let it stand for 30 minutes to separate layers to obtain the lower-layer liquid material. Repeat this step 5 times in total for separation.

[0124] 5. Concentrate and dehydrate the separated lower-layer liquid material for 2 - 3 h under the conditions of a water bath temperature of 60 °C and a vacuum degree of -0.08 MPa. Stop concentration when the water content of the lower-layer liquid material is less than 2% to obtain 0.94 kg of refined ginger extract.

[0125] After detection, the gingerol content in this refined ginger extract is 51.88 mg / g, the total recovery rate of gingerol is 94.69%, chlorpyrifos and imidacloprid are not detected (detection limit 0.1 ppm), thiamethoxam is 0.44 ppm, fosthiazate is 0.18 ppm, metalaxyl is 0.35 ppm, carbendazim is 0.54 ppm, and clothianidin is 0.21 ppm.

[0126] Example 5

[0127] This example provides a method for removing pesticide residues in ginger extract. This example uses Ginger Extract 1 as the raw material.

[0128] 1. Weigh 100.00 kg of Ginger Extract 1, add tap water with a volume 5 times the weight of the ginger extract, stir for 0.5 h to fully disperse the ginger extract, add a sodium hydroxide solution, adjust the pH to 12, and stir and react at 30 °C for 20 min to obtain Liquid Material 1 through full mixing and reaction.

[0129] 2. Add a calcium chloride solution with a volume 3 times that of the extract and a concentration of 30% to Liquid Material 1. After addition, stir and react at 30 °C for 1 h, let it stand for 0.5 h, then filter to separate the precipitate. Wash the precipitate with an alkaline solution with a volume 1 time that of the ginger extract and a pH of 12. Repeat the washing 3 times in total to obtain Precipitate 1.

[0130] 3. Put the first precipitate into acidic water with a pH of 1 and a volume 4 times that of the extract (L), heat to 50 °C and stir for 1.5 h. After full reaction, add sodium hydroxide to adjust the pH to 5, let it stand for 0.5 h for separation, and collect the lower layer of the liquid.

[0131] 4. Add 3 times the volume (L) of the ginger extract and 3% (mass / volume) of Tween 80 to the lower layer of the liquid, stir at 60 °C for 30 minutes, let it stand for 30 minutes for stratification to obtain the lower layer of the liquid, and repeat this step for a total of 4 separations.

[0132] 5. Concentrate and dehydrate the separated lower layer of the liquid for 2 - 3 h under the conditions of a water bath temperature of 65 °C and a vacuum degree of -0.08 MPa. Stop concentration when the water content of the lower layer of the liquid is less than 2% to obtain 96.12 kg of refined ginger extract.

[0133] After testing, the content of gingerol in this refined ginger extract is 51.78 mg / g, the total recovery rate of gingerol is 96.64%, chlorpyrifos and imidacloprid are not detected (detection limit 0.1 ppm), thiamethoxam is 0.42 ppm, fosthiazate is 0.28 ppm, metalaxyl is 0.37 ppm, carbendazim is 0.58 ppm, and clothianidin is 0.34 ppm.

[0134] Example 6

[0135] 1. Weigh 100.00 kg of ginger extract 1, add tap water with a volume 4 times that of the ginger extract (L), stir for 0.5 h to fully disperse the ginger extract, add sodium hydroxide solution, adjust the pH to 12.5, and stir and react at 25 °C for 10 min to obtain the first liquid.

[0136] 2. Add a calcium chloride solution with a volume 2 times that of the extract and a concentration of 30% to the first liquid. After adding, stir and react at 30 °C for 0.5 h, let it stand for 0.5 h and then filter to separate the precipitate. Wash the precipitate with alkaline water with a volume 1 time that of the ginger extract and a pH of 12.5, and repeat the washing for a total of 3 times to obtain the first precipitate.

[0137] 3. Put the first precipitate into acidic water with a pH of 2 and a volume 3 times that of the extract (L), heat to 50 °C and stir for 2 h. After full reaction, add sodium hydroxide to adjust the pH to 6, let it stand for 0.5 h for separation and collect the lower layer of the liquid.

[0138] 4. Add 2 times the volume (L) of the ginger extract and 2% (mass / volume) of Tween 20 to the lower layer of the liquid, stir at 60 °C for 30 minutes, let it stand for 30 minutes for stratification to obtain the lower layer of the liquid, and repeat this step for a total of 5 separations.

[0139] 5. Concentrate and dehydrate the separated lower-layer liquid for 2 - 3 h under the conditions of a water bath temperature of 65°C and a vacuum degree of -0.08 MPa. Stop concentrating when the water content of the lower-layer liquid is less than 2% to obtain 95.34 kg of refined ginger extract.

[0140] After testing, the gingerol content in this refined ginger extract is 51.24 mg / g, the total yield of gingerol is 94.86%, chlorpyrifos and imidacloprid are not detected (the detection limit is 0.1 ppm), thiamethoxam is 0.16 ppm, fosthiazate is 0.25 ppm, metalaxyl is 0.28 ppm, carbendazim is 0.45 ppm, and clothianidin is 0.23 ppm.

[0141] Comparative Example 1

[0142] This comparative example provides a method for removing pesticide residues in ginger extract. The specific method is basically the same as that in Example 1, except that in step 2, a calcium chloride solution with a volume 1 times that of the ginger extract and a mass percentage concentration of 15% is added to Liquid 1. The reaction temperature is 30°C and the reaction time is 1 h. The other steps are the same as those in Example 1.

[0143] Finally, 0.92 kg of refined ginger extract is obtained.

[0144] After testing, the gingerol content in this refined ginger extract is 48.13 mg / g, the yield is 84.11%, chlorpyrifos is 0.81 ppm, imidacloprid is 0.74 ppm, thiamethoxam is 1.52 ppm, fosthiazate is 1.12 ppm, metalaxyl is 1.36 ppm, carbendazim is 1.89 ppm, and clothianidin is 0.95 ppm.

[0145] Since the pesticide residues in the refined ginger extract are relatively high, when it is prepared into a 5% powder or liquid gingerol product, the pesticide residue content is higher than the EU standard. Moreover, the yield of gingerol in Comparative Example 1 is relatively low, and the economic benefit is low.

[0146] Comparative Example 2

[0147] This comparative example provides a method for removing pesticide residues in ginger extract. The specific method is basically the same as that in Example 1, except that in step 4, a Tween 20 solution with a volume 2 times that of the ginger extract and a concentration of 1% is added to the lower-layer liquid obtained in step 3. Stir at 60°C for 30 minutes, let it stand for 30 minutes to separate layers, and repeat this step a total of 2 times. The other steps are the same as those in Example 1. Finally, 0.94 kg of refined ginger extract is obtained.

[0148] After detection, the content of gingerol in the refined ginger extract is 51.99 mg / g, and the content yield is 95.39%. The contents of chlorpyrifos, imidacloprid, thiamethoxam, fosthiazate, metalaxyl, carbendazim, and clothianidin are 1.02 ppm, 0.66 ppm, 0.65 ppm, 0.49 ppm, 1.22 ppm, 1.89 ppm, and 0.56 ppm, respectively. The refined ginger extract is prepared into a 5% powder or liquid gingerol product, and most of the pesticide residues in the gingerol product are higher than the EU standards.

[0149] Comparative Example 3

[0150] This comparative example provides a method for removing pesticide residues from ginger extract. The specific method is basically the same as that of Example 1, except that in Step 2, a magnesium chloride solution with a volume 2 times that of the ginger extract and a mass percentage concentration of 30% is added to the first material liquid, the reaction temperature is 30 °C, and the reaction time is 1 h. The remaining steps are the same as those of Example 1.

[0151] As a result, magnesium hydroxide precipitates are formed under alkaline conditions by the magnesium chloride solution, and gingerol cannot be precipitated.

[0152] Comparative Example 4

[0153] This comparative example provides a method for removing pesticide residues from ginger extract. Referring to the method of Example 1, only the methods in Steps 1, 2, 3, and 5 of Example 1 are adopted, and Step 4 is omitted. Specifically:

[0154] 1. Weigh 1.00 kg of ginger extract 1, add tap water with a volume 3 times that of the ginger extract by weight (L), stir for 0.5 h to fully disperse the ginger extract, add sodium hydroxide solution, adjust the pH = 12.5, and stir and react at 25 °C for 10 min to obtain the first material liquid after sufficient mixing and reaction;

[0155] 2. Add a calcium chloride solution with a volume 2 times that of the extract and a concentration of 30% to the first material liquid. After adding, stir and react at 30 °C for 0.5 h, let it stand for 0.5 h, then filter and separate the precipitate, and rinse the precipitate with alkaline water with a volume 1 time that of the ginger extract and a pH = 12.5. Repeat the rinsing 3 times in total to obtain the first precipitate;

[0156] 3. Put the first precipitate into acid water with a pH = 2 and a volume 3 times that of the extract, heat to 50 °C and stir for 2 h. After sufficient reaction, add sodium hydroxide to adjust the pH = 6, let it stand for 0.5 h, and separate and collect the lower-layer material liquid;

[0157] 4. Concentrate and dehydrate the separated lower-layer material liquid under the conditions of a water bath temperature of 65 °C and a vacuum degree of -0.08 MPa for 1.5 - 2.5 h. Stop concentrating when the water content of the lower-layer material liquid is less than 2% to obtain 0.95 kg of refined ginger extract.

[0158] After detection, the content of gingerol in the refined ginger extract is 52.64 mg / g, the content yield is 97.10%, and the contents of chlorpyrifos, imidacloprid, thiamethoxam, fosthiazate, metalaxyl, carbendazim, and clothianidin are 0.64 ppm, 0.45 ppm, 0.84 ppm, 0.98 ppm, 0.86 ppm, 1.23 ppm, and 0.79 ppm respectively. The refined ginger extract is prepared into a 5% powder or liquid gingerol product, and the pesticide residues in the gingerol product are all higher than the EU standards.

[0159] Comparative Example 5

[0160] This comparative example provides a method for removing pesticide residues in ginger extract. Referring to the method of Example 1, the methods in steps 1, 4, and 5 are used alone. Specifically:

[0161] 1. Weigh 1.00 kg of ginger extract 1, add tap water with a volume three times that of the ginger extract (L), stir for 0.5 h to fully disperse the ginger extract, add sodium hydroxide solution, adjust the pH to 12.5, and stir and react at 25 °C for 10 min to obtain liquid material 1 after sufficient mixing reaction;

[0162] 2. Add 2 times the volume (L) of the ginger extract and 2% (mass / volume) Tween 20 to liquid material 1, stir at 60 °C for 30 minutes, let it stand for 30 minutes to separate layers, and obtain the lower-layer liquid material. Repeat this step for a total of 5 separations;

[0163] 3. Concentrate and dehydrate the separated lower-layer liquid material under the conditions of a water bath temperature of 65 °C and a vacuum degree of -0.08 MPa for 1.5 - 2.5 h. Stop concentrating when the water content of the lower-layer liquid material is less than 2% to obtain 0.95 kg of refined ginger extract.

[0164] After detection, the content of gingerol in the refined ginger extract is 52.16 mg / g, the content yield is 96.22%, and the contents of chlorpyrifos, imidacloprid, thiamethoxam, fosthiazate, metalaxyl, carbendazim, and clothianidin are 1.89 ppm, 1.45 ppm, 2.13 ppm, 2.25 ppm, 5.23 ppm, 5.23 ppm, and 1.24 ppm respectively. The refined ginger extract is prepared into a 5% powder or liquid gingerol product, and the pesticide residues in each item are all higher than the EU standards.

[0165] Comparative Example 6

[0166] Referring to the method of Example 1 in Chinese Patent CN116474415A, a method for removing pesticide residues in oleoresin ginger is provided.

[0167] The specific steps are as follows:

[0168] Weigh 400 g of ginger oleoresin raw material and put it into the supercritical carbon dioxide extraction kettle. Then, introduce supercritical carbon dioxide into the supercritical extraction kettle. The extraction pressure is increased to 16 MPa, the temperature of the extraction kettle is 55 °C, the extraction time is 2 h, the flow rate is 9 L / h, and the weight of the entrainer glyceryl caprylocaprate is 120 g. The extract enters the first separation kettle. Control the pressure of the separation kettle to be 8.8 MPa and the temperature to be 43 °C to collect the pesticide residues, and the yield of the pesticide residues is 64.15%. The pressure of the second separation kettle is 5.5 MPa and the temperature is 35 °C to collect the ginger essential oil without pesticide residues.

[0169] Continue to increase the pressure of the extraction kettle to 27 MPa, the temperature of the extraction kettle is 50 °C, the extraction time is 2 h, the flow rate is 6 L / h, and 40 g of ginger essential oil without pesticide residues is used as the entrainer. The extract enters the third separation kettle. Control the pressure of the separation kettle to be 8.8 MPa and the temperature to be 43 °C to collect the ginger oleoresin with low pesticide residues, and the pesticide residue content is 3.18 ppm. The pressure of the fourth separation kettle is 5.5 MPa and the temperature is 35 °C to collect the ginger essential oil without pesticide residues. The organic chlorine pesticide residues and impurities are collected in the extraction kettle. There is basically no gingerol in the first separation kettle and the last extraction kettle, and the ginger oleoresin obtained in the third separation kettle has a high gingerol content.

[0170] This patent is the aforementioned patent of the applicant, so it is directly cited to compare and evaluate the technical solutions and beneficial effects of this application.

[0171] In this comparative example, the ginger oleoresin raw material is the ginger oleoresin with excessive pesticide residues extracted by the solvent extraction method, and the pesticide residue content is 132.93 ppm, including pesticides such as cypermethrin, bifenthrin, fosthiazate, clothianidin, and thiamethoxam. When this raw material is refined by the supercritical carbon dioxide extraction kettle, an entrainer needs to be used to obtain the ginger oleoresin with low pesticide residues.

[0172] The total pesticide residue content of the refined ginger oleoresin obtained by this patent is between 3 - 5 ppm. When it is subsequently prepared into a 5% powder or liquid gingerol product, there are individual cases where the pesticide residues exceed the standard and it cannot fully meet the EU standards.

[0173] On the contrary, in the method of this application, the ginger extract raw material (ginger oleoresin, with a pesticide residue content of about 28 ppm - 30 ppm) obtained by supercritical carbon dioxide extraction is first used, and then the pesticide residues in it are removed to obtain the refined ginger extract. The 5% powder or liquid gingerol product prepared from the refined ginger extract has a pesticide residue content that meets the EU standards.

[0174] If the method of this comparative example is referred to and supercritical carbon dioxide extraction is repeated twice. Due to the high investment and maintenance costs of high-pressure equipment, large energy consumption, and the further increase in costs for the use and recovery of the entrainer, the economic benefits are low and it is not conducive to large-scale promotion.

[0175] It is found in the research of this application that using some methods for removing pesticide residues in ginger extract alone or partially can achieve certain effects. However, the pesticide residues in the gingerol product with a content of 5% obtained still cannot meet the EU standards. In the research of this application, we explored many methods and combined them in various ways, and finally obtained the technical solution of this application. Through this method, the pesticide residues in the ginger extract can be basically removed, and a gingerol product meeting the EU standards can be obtained. This method is of great significance for facilitating the export of Chinese ginger products abroad and can enhance the overall competitiveness of Chinese agriculture.

[0176] The above is a further detailed description of the present invention and should not be regarded as a limitation on the specific implementation of the present invention. For those of ordinary skill in the technical field to which the present invention pertains, any simple deduction or replacement without departing from the concept of the present invention falls within the protection scope of the present invention.

Claims

1. A method for removing pesticide residues in ginger extract, characterized in that, It includes the following steps: (1) Add water to the raw material of ginger extract to fully disperse it, then add an alkali to adjust the pH, and carry out hydrolysis and neutralization reactions to obtain the first material liquid; (2) Add a calcium chloride solution to the first material liquid to react to form a precipitate, and separate to obtain the precipitate; (3) Add an acid solution to the precipitate for acidolysis reaction, then let it stand for layering, and separate to obtain the lower first material liquid; (4) Add a surfactant to the lower first material liquid for emulsification, then let it stand for layering, and separate to obtain the lower second material liquid; (5) Carry out dehydration treatment on the lower second material liquid to obtain ginger extract.

2. The method according to claim 1, wherein In step (1), the mass-volume ratio of the raw material of ginger extract to water is 1:(2 - 5) g / mL.

3. The method according to claim 1, wherein In step (1), the alkali is one or both of sodium hydroxide and potassium hydroxide, and / or, add an alkali to adjust the pH value to 12 - 13.

4. The method according to any one of claims 1 to 3, characterized in that, In step (1), the reaction temperature of the hydrolysis and neutralization reactions is 20 - 30°C, and the reaction time ≤ 30 min.

5. The method according to claim 1, wherein In step (2), the mass percentage concentration of the calcium chloride solution is 20 - 50%; and / or, the mass-volume ratio of the raw material of ginger extract to the calcium chloride solution is 1:(1 - 3) g / mL.

6. The method according to claim 1 or 5, characterized in that, In step (2), the reaction temperature for adding the calcium chloride solution for reaction is 20 - 40°C, and the reaction time is 0.2 - 1 h.

7. The method according to claim 1 or 5, characterized in that, In step (2), the precipitate also includes the step of rinsing with an alkali solution with a pH of 12 - 13.

8. The method according to claim 1, characterized in that, In step (3), the conditions for the acidolysis reaction include any one of a) - e): a) The mass-volume ratio of the raw material of ginger extract to the acid solution is 1:(2 - 5) g / mL; and / or; b) The pH of the acid solution is 1 - 2, and / or; c) The temperature of the acidolysis reaction is 25 - 55°C, preferably 30 - 50°C; and / or; d) The reaction time of the acidolysis reaction is 1 - 3 h; and / or; e) After the acidolysis reaction is completed, add an alkali to adjust the pH to 4 - 6 and then let it stand for layering.

9. The method according to claim 1, wherein In step (4), the surfactant is polyoxyethylene sorbitan fatty acid ester, including at least one of polyoxyethylene sorbitan monolaurate (Tween 20), polyoxyethylene sorbitan monopalmitate (Tween 40), and polyoxyethylene sorbitan monooleate (Tween 80), and / or, the mass-volume fraction of the surfactant is 2 - 5%; and / or, the mass-volume ratio of the raw material of ginger extract to the surfactant solution is 1:(2 - 5) g / mL.

10. A ginger extract, characterized in that, The ginger extract is prepared by the method according to any one of claims 1 - 9.

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