Method for removing pesticide residues in carotenoid crystals

Abstract

The invention provides a method for removing pesticide residues in carotenoid crystals, which comprises the following steps: dissolving the carotenoid crystals in a mixed solvent, then adding absolute ethyl alcohol into the mixed solvent, then slowly adding water until the ethanol concentration is 20-30%, uniformly shaking, standing and extracting; after extracting for 1-3 times, concentrating an organic layer under reduced pressure to obtain a concentrated solution; and dissolving the concentrated solution in the mixed solvent again, rapidly carrying out gradient heating and cooling crystallization for multiple times, filtering, washing, carrying out vacuum drying, and crushing to obtain the carotenoid crystal with low pesticide residue. According to the method, the water-soluble and fat-soluble pesticide residues in the carotenoid crystal are respectively removed by adopting a method of combining mixed solvent extraction and recrystallization technologies, the process flow is simple, the cost is low, the used solvent is low in toxicity and easy to recover, and the green low-pesticide-residue carotenoid crystal is prepared and can be applied to large-scale production.

Description

Technical Field

[0001] The invention relates to a method for removing pesticide residues in carotenoid crystals, and belongs to the field of plant extraction and processing of natural effective ingredients. Background Art

[0002] Carotenoids are a general term for an important class of natural pigments. They are commonly found in microorganisms, animals, plants, fungi and algae. Common carotenoids include lutein, lycopene, zeaxanthin, etc. Natural carotenoids are an important antioxidant with excellent properties, which have antioxidant, immunomodulatory, anti-cancer and anti-aging effects.

[0003] The industrial preparation methods of carotenoids mainly include chemical synthesis, biosynthesis and natural extraction. In today's society, people have higher and higher requirements for green food. Extracting carotenoids directly from natural raw materials is undoubtedly the best and most trusted method. However, the spraying of pesticides during the planting of raw materials causes pesticide residues, and the conversion of raw materials into final products still enriches harmful components such as pesticide residues, thereby damaging the effective ingredients in carotenoids and reducing the beneficial effects on the human body. Therefore, it is very necessary to remove pesticide residues from carotenoids. The pesticide residues in carotenoid crystals are water-soluble pesticides and fat-soluble pesticides. The main pesticide residues are diphenylamine, ammonium sulfonate, biphenyl, tebuconazole and difenoconazole. At present, there are few studies on the process of removing pesticide residues from carotenoid crystals at home and abroad. Commonly used pesticide residue removal processes such as resin adsorption, supercritical extraction, activated carbon adsorption, etc. are relatively complex and not suitable for removing pesticide residues from carotenoid crystals.

[0004] Patent document CN103550273A discloses a method for extracting low-pesticide residue ginsenosides from ginseng, which uses cold water to extract ginseng, concentrates it, extracts it with a solvent, concentrates it, applies it to a macroporous resin column, rinses it with water, then elutes it with ethanol, collects the eluate, and dries it. This process uses solvent extraction and resin adsorption purification to obtain low-pesticide residue ginsenosides, but the disadvantage is that it may cause pesticide residue problems in the resin, the resin is frequently regenerated, the production cost is high, and the efficiency is low.

[0005] Patent document CN106880655A discloses a method for producing food and drug extracts without pesticide residues, in which food and drug extracts without pesticide residues are prepared by heating reflux extraction and anionic and cationic resin adsorption processes. The disadvantage is that the operation is complicated and the applicability is small.

[0006] Patent document CN116211906A discloses a preparation process of a low-pesticide residue ginseng extract, in which ginseng is extracted using low-temperature plasma technology and composite enzyme extraction technology, and then vacuum concentrated and spray dried to obtain the low-pesticide residue ginseng extract. However, the disadvantage is that the processing volume is small and it is not suitable for industrial production.

[0007] In summary, research and development of carotenoid crystals to remove pesticide residues and develop high-quality, low-pesticide residue carotenoid products have important practical significance, and the technology of carotenoid pesticide residue removal needs to be urgently solved. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a method for removing pesticide residues in carotenoid crystals, which has the advantages of simple operation, high reproducibility, low production cost, and is suitable for continuous large-scale industrial production. The pesticide residues of each type in the prepared carotenoid crystals are less than 0.05 ppm.

[0009] In order to solve the above technical problems, the technical solution adopted by the present invention is: A method for removing pesticide residues in carotenoid crystals comprises the following steps: The carotenoid crystals are dissolved in a mixed solvent, and then anhydrous ethanol is added thereto, and then water is slowly added to the mixed solvent until the ethanol concentration is 20-30%, and the mixture is shaken, allowed to stand, and extracted; after extraction for 1-3 times, the organic layer is concentrated under reduced pressure to obtain a concentrated solution; the concentrated solution is dissolved again in the mixed solvent, and multiple gradient temperature rise and drop crystallizations are rapidly performed, and the mixture is filtered, washed, vacuum dried, and crushed to obtain carotenoid crystals with low pesticide residues.

[0010] Preferably, the mixed solvent is two or more of n-hexane, ethyl acetate, petroleum ether and diethyl ether.

[0011] More preferably, the mixed solvent is formed by mixing ethyl acetate and n-hexane in a volume ratio of 1:3-5.

[0012] Preferably, the mass volume ratio m:v of the carotenoid to the mixed solvent is 1:5-10.

[0013] More preferably, the mass volume ratio m:v of the carotenoid to the mixed solvent is 1:7.

[0014] Preferably, the volume ratio of the mixed solvent to anhydrous ethanol is 1:0.3-0.7, water is slowly added until the ethanol concentration is 20-30%, and then the mixture is allowed to stand for 5-20 minutes, and the aqueous phase and the organic phase are extracted and separated to obtain an organic phase.

[0015] More preferably, the volume ratio of the mixed solvent to anhydrous ethanol is 1:0.5, water is slowly added to an ethanol concentration of 30%, the standing time is 15 minutes, and extraction is performed 3 times.

[0016] Preferably, the vacuum degree during the reduced pressure concentration is -0.08 to -0.09 MPa, and the temperature is 68 to 72°C.

[0017] More preferably, the vacuum degree during the reduced pressure concentration is -0.08 MPa and the temperature is 70°C.

[0018] Preferably, the volume of the concentrated solution is 10-20% of the volume before concentration.

[0019] Preferably, the volume ratio of the concentrated solution to the mixed solvent is 1:4-10.

[0020] Preferably, the heating temperature in the gradient heating and cooling is 50-30°C; the cooling temperature is 20-5°C.

[0021] Preferably, the washing adopts the mixed solvent.

[0022] Preferably, the ratio of the amount of the washing solvent to the mass of the carotenoid is 1:0.5-2.

[0023] Furthermore, the carotenoids described in the present invention include lutein, lycopene and zeaxanthin.

[0024] Due to the adoption of the above technical solution, the technical progress achieved by the present invention is: (1) The present invention removes water-soluble and fat-soluble pesticide residues from carotenoids simultaneously by combining extraction and recrystallization. Recrystallization and extraction each have the ability to remove pesticide residues, but when they are used in combination, a synergistic effect can be produced, thereby further improving the removal efficiency.

[0025] (2) The present invention can achieve more efficient removal of pesticide residues by optimizing the operating conditions and parameters of the two. The extraction technology achieves better removal effect of water-soluble pesticide residues by adding relatively medium-polar ethanol to assist dissolution; the mixed solvent can be applied to both the recrystallization and extraction processes and can achieve higher selectivity and pesticide residue removal effect; the recrystallization technology achieves better removal effect of fat-soluble pesticide residues wrapped on the surface of the crystal by rapidly and repeatedly increasing and decreasing the temperature in a gradient.

[0026] (3) The present invention has good pesticide residue removal effect, simple process operation, and obtains high-quality low-pesticide residue carotenoid crystals, which is suitable for large-scale continuous industrial production. DETAILED DESCRIPTION

[0027] In order to better understand the content of the present invention, the following is further described in conjunction with specific embodiments. It should be understood that these embodiments are only used to further illustrate the present invention, and are not used to limit the scope of the present invention. In addition, it should be understood that after reading the content of the present invention, the technicians in this field make some non-essential changes or adjustments to the present invention, which still fall within the protection scope of the present invention.

[0028] Unless otherwise specified, the raw materials, auxiliary materials, equipment, etc. used in the following examples were purchased from regular channels.

[0029] The raw materials used in the following examples are carotenoid crystals with a total carotenoid content of 80-92% with excessive pesticide residues. Example 1

[0030] A method for removing pesticide residues in lutein crystals comprises the following steps: Weigh 100g of lutein crystals, add 7 times the volume of ethyl acetate and n-hexane (volume ratio of 1:3) mixed solvent, stir and dissolve at 25℃; after dissolution, add 350mL of anhydrous ethanol, then slowly add 820mL of water, shake well, let stand for 15min, separate the liquid using a separatory funnel, take the upper layer, and extract repeatedly for 2 times. The organic phases after extraction were mixed, and concentrated under reduced pressure to 10% of the original volume at a vacuum degree of -0.08 MPa and a temperature of 70°C to obtain 200 ml of concentrated solution; 980 mL of a mixed solvent of ethyl acetate and n-hexane (volume ratio of 1:3) was added to the concentrated solution again, and after thorough mixing, the temperature was rapidly raised to 50°C, maintained for 20 minutes, and then cooled to 20°C, maintained for 20 minutes, and then heated to 40°C again, maintained for 20 minutes, and then cooled to 10°C, maintained for 20 minutes, and then heated to 30°C again, maintained for 20 minutes, and then cooled to 5°C, maintained for 20 minutes, and then filtered, washed twice with 100 mL of the above mixed solvent, vacuum dried, and crushed to obtain the product. Example 2

[0031] A method for removing pesticide residues in zeaxanthin crystals comprises the following steps: Weigh 100g of zeaxanthin crystals, add 10 times the volume of a mixed solvent of ethyl acetate and petroleum ether (volume ratio of 1:3), and stir to dissolve at 25°C; after dissolution, add 300mL of anhydrous ethanol, then slowly add 900mL of water, shake well, let stand for 5min, separate the liquid using a separatory funnel, take the upper layer, and extract repeatedly twice. The organic phases after extraction were mixed, and concentrated under reduced pressure to 10% of the original volume at a vacuum degree of -0.08 MPa and a temperature of 70°C to obtain 200 ml of concentrated solution; 980 mL of a mixed solvent of ethyl acetate and petroleum ether (volume ratio of 1:3) was added to the concentrated solution again, and the mixture was fully mixed. The mixture was rapidly heated to 50°C, maintained for 20 min, and then cooled to 20°C. The mixture was heated to 40°C again after being maintained for 20 min, and then cooled to 10°C after being maintained for 20 min. The mixture was heated to 30°C again after being maintained for 20 min, and then cooled to 5°C after being maintained for 20 min. The mixture was filtered after being maintained for 20 min, and washed twice with 50 mL of the mixed solvent, dried under vacuum, and crushed to obtain the product. Example 3

[0032] A method for removing pesticide residues in lycopene crystals comprises the following steps: Weigh 100g of lycopene crystals, add 5 times the volume of ethyl acetate and ether (volume ratio of 1:3) mixed solvent, stir and dissolve at 25℃; after dissolution, add 350mL of anhydrous ethanol, then slowly add 1400mL of water, shake well, let stand for 20min, use a separatory funnel to separate the liquid, take the upper layer, and extract it repeatedly twice. Mix the organic phases after extraction, and reduce the pressure to 10% of the original volume under vacuum degree -0.09Mpa and temperature 70℃ to obtain 100ml of concentrated solution; add 980mL of ethyl acetate and ether (volume ratio of 1:3) mixed solvent to the concentrated solution again, mix thoroughly, quickly heat to 45℃, keep it for 10min, then cool it to 15℃, keep it for 10min, heat it again to 30℃, keep it for 10min, then cool it to 5℃, keep it for 10min, filter it, wash it twice with 200mL of the above mixed solvent, vacuum dry it, and crush it to obtain it. Example 4

[0033] A method for removing pesticide residues in lutein crystals comprises the following steps: Weigh 100g of lutein crystals, add 8 times the volume of a mixed solvent of n-hexane and petroleum ether (volume ratio of 1:3), and stir to dissolve at 25°C; after dissolution, add 400mL of anhydrous ethanol, then slowly add 1000mL of water, shake well, let stand for 15 minutes, separate the liquid using a separatory funnel, take the upper layer, and extract repeatedly twice. The organic phases after extraction were mixed, and concentrated under reduced pressure to 10% of the original volume at a vacuum degree of -0.085 MPa and a temperature of 70°C to obtain 240 ml of concentrated solution; 980 mL of a mixed solvent of n-hexane and petroleum ether (volume ratio of 1:3) was added to the concentrated solution again, and after thorough mixing, the temperature was rapidly raised to 50°C, maintained for 20 min, then cooled to 20°C, maintained for 20 min, then heated to 40°C again, maintained for 20 min, then cooled to 10°C, maintained for 20 min, then heated to 30°C again, maintained for 20 min, then cooled to 5°C, maintained for 20 min, filtered, washed twice with 100 mL of the above mixed solvent, vacuum dried, and crushed to obtain the product. Comparative Example 1

[0034] A method for removing pesticide residues in carotenoid crystals comprises the following steps: Weigh 100g of lutein crystals, add 7 times the volume of ethyl acetate and n-hexane (volume ratio of 1:3) mixed solvent, stir and dissolve at 25℃; after dissolution, add 1170ml of 30% ethanol aqueous solution, use a separatory funnel to separate the liquid, take the upper layer, and extract it repeatedly twice. Mix the extracted organic phases, and concentrate to 10% of the original volume under vacuum degree -0.08Mpa and temperature 70℃ under reduced pressure to obtain 200ml of concentrated solution; add 980mL of ethyl acetate and n-hexane (volume ratio of 1:3) mixed solvent to the concentrated solution again, mix thoroughly, quickly heat to 50℃, keep it for 20min and then cool it to 20℃, keep it for 20min and then heat it to 40℃ again, keep it for 20min and then cool it to 10℃, keep it for 20min and then heat it to 30℃ again, keep it for 20min and then cool it to 5℃, keep it for 20min and then filter it, wash it twice with 100mL of the above mixed solvent, vacuum dry it, and crush it to obtain it. Comparative Example 2

[0035] A method for removing pesticide residues in carotenoid crystals comprises the following steps: Weigh 100g of lutein crystals, add 7 times the volume of ethyl acetate solvent, stir and dissolve at 25℃; after dissolution, add 350mL of anhydrous ethanol, then slowly add 820mL of water, shake well, let stand for 15min, separate the liquid using a separatory funnel, take the upper layer, and extract it repeatedly twice. Mix the organic phases after extraction, and concentrate to 10% of the original volume under vacuum degree -0.08Mpa and temperature 70℃ under reduced pressure to obtain 200ml of concentrated solution; add 980mL of ethyl acetate solvent to the concentrated solution again, mix thoroughly, quickly heat to 50℃, keep it for 20min and then cool it to 20℃, keep it for 20min and then heat it to 40℃ again, keep it for 20min and then cool it to 10℃, keep it for 20min and then heat it to 30℃ again, keep it for 20min and then cool it to 5℃, keep it for 20min and then filter it, wash it twice with 100mL of mixed solvent, vacuum dry it, and crush it to obtain it. Comparative Example 3

[0036] A method for removing pesticide residues in carotenoid crystals comprises the following steps: Weigh 100g of lutein crystals, add 7 times the volume of ethyl acetate and petroleum ether (volume ratio of 1:3) mixed solvent, stir and dissolve at 25℃; after dissolution, add 350mL of anhydrous ethanol, then slowly add 820mL of water, shake well, let stand for 15min, use a separatory funnel to separate the liquid, take the upper layer, and extract it repeatedly twice. Mix the organic phases after extraction, and reduce the pressure to 10% of the original volume under vacuum degree -0.08Mpa and temperature 70℃ to obtain 150ml of concentrated solution; add 980mL of ethyl acetate and petroleum ether (volume ratio of 1:3) mixed solvent to the concentrated solution again, mix thoroughly, filter, wash twice with 100mL of mixed solvent, vacuum dry, and crush to obtain.

[0037] The total carotenoid content and pesticide residue content of the carotenoid crystals of each embodiment and comparative example before and after the pesticide residue removal treatment were tested, and the results are shown in Table 1.

[0038] Table 1 Comparison of total carotenoids and pesticide residues before and after treatment in each example and comparative example

[0039] As shown in Table 1, the method of the present invention can control the contents of pesticide residues such as diphenylamine, phosphamidon, biphenyl, tebuconazole and difenoconazole to below 0.05 ppm, and can well retain the total content of carotenoids while removing the pesticide residues.

[0040] However, as described in Comparative Example 1, after the lutein crystals were dissolved in a mixed solvent, 30% ethanol water was directly used for extraction, which failed to remove the tebuconazole pesticide residue. As described in Comparative Example 2, the lutein crystals were dissolved in a single solvent for extraction and recrystallization, and as described in Comparative Example 3, the lutein crystals were extracted and recrystallized without cooling and precipitation, which failed to effectively remove the pesticide residue.

[0041] Although the present invention has been described in detail above by means of general description, specific implementation methods and experiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention are within the scope of protection claimed by the present invention.

Claims

1. A method for removing pesticide residues from carotenoid crystals, characterized in that: The method comprises the following steps: dissolving carotenoid crystals in a mixed solvent, then adding anhydrous ethanol thereto, then slowly adding water to an ethanol concentration of 20-30%, shaking, standing, and extracting; after extracting 1-3 times, concentrating the organic layer under reduced pressure to obtain a concentrated solution; dissolving the concentrated solution again in the mixed solvent, rapidly performing multiple gradient temperature rise and fall crystallizations, filtering, washing, vacuum drying, and crushing to obtain low pesticide residue carotenoid crystals.

2. The method for removing pesticide residues in carotenoid crystals according to claim 1, characterized in that: The mixed solvent is two or more of n-hexane, ethyl acetate, petroleum ether and ether.

3. The method for removing pesticide residues in carotenoid crystals according to claim 1, characterized in that: The mass volume ratio m:v of the carotenoid and the mixed solvent is 1:5-10.

4. The method for removing pesticide residues in carotenoid crystals according to claim 1, characterized in that: The volume ratio of the mixed solvent to anhydrous ethanol is 1:0.3-0.7, water is slowly added until the ethanol concentration is 20-30%, and then the mixture is allowed to stand for 5-20 minutes, and the aqueous phase and the organic phase are extracted and separated to obtain an organic phase.

5. The method for removing pesticide residues in carotenoid crystals according to claim 1, characterized in that: The vacuum degree during the reduced pressure concentration is -0.08 to -0.09 MPa, and the temperature is 68 to 72°C.

6. The method for removing pesticide residues in carotenoid crystals according to claim 1, characterized in that: The volume of the concentrated solution is 10-20% of the volume before concentration.

7. The method for removing pesticide residues in carotenoid crystals according to claim 1, characterized in that: The volume ratio of the concentrated solution to the mixed solvent is 1:4-10.

8. The method for removing pesticide residues in carotenoid crystals according to claim 1, characterized in that: The heating temperature in the gradient heating and cooling is 50-30°C; the cooling temperature is 20-5°C.

9. The method for removing pesticide residues in carotenoid crystals according to claim 1, characterized in that: The washing adopts the mixed solvent.

10. The method for removing pesticide residues in carotenoid crystals according to claim 1, characterized in that: The volume ratio of the washing solvent to the mass ratio of the carotenoid is 1:0.5-2.

Images