Method for extracting capsicum oleoresin from capsicum

Abstract

The invention belongs to the technical field of capsicum oleoresin extraction, and provides a method for extracting capsicum oleoresin from capsicum. The method comprises the following steps: (1) pretreatment of raw materials: drying chilies and then crushing the chilies to obtain chilli powder; (2) supercritical extraction: controlling the internal pressure of an extraction kettle to be 15-20Mpa and the ratio of the volume of introduced COfluid to the dosage of the chili powder to be (15-25L): 1kg, extracting at 34-36 DEG C for 29-31 minutes, heating to 39-41 DEG C, extracting for 29-31 minutes, cooling to 36-38 DEG C, and extracting for 29-31 minutes to obtain a mixed fluid; and (3) after extraction is completed, mixed fluid enters a separation kettle, separated capsicum oleoresin is separated and collected through a filter screen and then subjected to vacuum deodorization, filtration and refining, and a finished product is obtained. According to the method, the capsicum oleoresin which is high in yield and rich in capsanthin can be obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of oleoresin capsici extraction, and specifically relates to a method for extracting oleoresin capsici from chili peppers. Background Art

[0002] As the main active ingredient in chili peppers, oleoresin capsici is widely used in food flavoring, healthcare, cosmetics and other fields. It is rich in capsanthin and capsaicinoids, which not only endow products with unique colors, but also have biological activities such as anti-inflammatory and antioxidant effects.

[0003] Among them, capsanthin is a natural carotenoid pigment, mainly composed of components such as capsorubin and capsanthin, and has the characteristics of bright color, strong coloring power, safety and non-toxicity. In the food industry, capsanthin, as an ideal natural colorant, can replace synthetic pigments and be applied to products such as meat products, seasonings, and beverages to meet consumers' demands for healthy foods; in the cosmetics field, due to its antioxidant properties, it can be used in skin care products to delay skin aging; in the pharmaceutical industry, the biological activities of capsanthin contribute to the development of functional preparations such as anti-inflammatory and anti-tumor agents.

[0004] At present, the extraction methods of oleoresin capsici mainly include organic solvent extraction method, steam distillation method and supercritical CO2 extraction method. The organic solvent extraction method uses organic solvents such as n-hexane and ethanol. Although the extraction efficiency is relatively high, there is a risk of solvent residue, which affects the safety and quality of products; the steam distillation method is simple to operate, but high temperature will destroy heat-sensitive components, resulting in serious loss of effective components such as capsanthin. In contrast, the supercritical CO2 extraction method has become the mainstream technology for oleoresin capsici extraction due to its advantages of environmental friendliness, no solvent residue, and low extraction temperature.

[0005] However, the existing supercritical CO2 extraction method still has deficiencies. On the one hand, it is difficult to achieve efficient separation of capsanthin and capsaicinoids during the extraction process, resulting in a low content of capsanthin in the product and making it difficult to meet the needs of the high-end market for products with high color value; on the other hand, the control of traditional extraction process parameters is rough, the extraction efficiency is low, and the energy consumption is high, which limits large-scale industrial production.

[0006] Therefore, there is an urgent need to improve the supercritical CO2 extraction method at present to obtain high-purity oleoresin capsici rich in capsanthin and enhance the added value and production efficiency of products. Summary of the Invention

[0007] Aiming at the above deficiencies in the prior art, the purpose of the present invention is to provide a method for extracting oleoresin capsici from chili peppers, which can obtain oleoresin capsici with high yield and rich in capsanthin.

[0008] To achieve the above object, the solution adopted by the present invention is as follows: A method for extracting oleoresin from chili peppers, comprising: (1) raw material pretreatment: drying and pulverizing chili peppers to obtain chili powder; (2) supercritical extraction: controlling the internal pressure in the extraction kettle to be 15-20 Mpa, and the ratio of the volume of CO2 fluid introduced to the amount of chili powder used is 15-25 L: 1 kg, extracting at 34-36 °C for 29-31 min, then heating to 39-41 °C and extracting for 29-31 min, and then cooling to 36-38 °C and extracting for 29-31 min to obtain a mixed fluid; (3) after the extraction is completed, the mixed fluid enters the separation kettle, and the precipitated oleoresin is separated and collected through a filter screen and then subjected to vacuum deodorization and filtration refinement to obtain the finished product.

[0009] Further, in a preferred embodiment of the present invention, in step (2), before introducing the CO2 fluid into the extraction kettle, n-hexane is added to the CO2 fluid at 4-6% of the volume of the CO2 fluid, and after mixing in a static mixer, it is reserved for use.

[0010] Further, in a preferred embodiment of the present invention, in step (2), the CO2 fluid is heated to 35 °C and then mixed with n-hexane.

[0011] Further, in a preferred embodiment of the present invention, in step (2), an ultrasonic transducer is installed on the inner wall of the extraction kettle, the working frequency of the ultrasonic transducer is 20 kHz, the power density is set to 0.3-0.5 W / cm², and ultrasonic waves are applied in the first 30 min of extraction.

[0012] Further, in a preferred embodiment of the present invention, in step (3), multi-stage separation is adopted: primary separation: setting the pressure to 8-10 MPa and the temperature to 40-45 °C; secondary separation: setting the pressure to 5-6 MPa and the temperature to 30-35 °C; tertiary separation: setting the pressure to 2-3 MPa and the temperature to 20-25 °C.

[0013] Further, in a preferred embodiment of the present invention, in step (1), the particle size of the chili powder is 0.4-0.85 mm.

[0014] Further, in a preferred embodiment of the present invention, in step (1), the chili peppers are dried by hot air to a moisture content ≤ 6%.

[0015] Further, in a preferred embodiment of the present invention, in step (1), before drying, the chili peppers are pretreated to remove spiciness: the chili peppers are soaked in ethanol with a concentration of 50% at 40 °C for 30 min, filtered and then dried.

[0016] Further, in a preferred embodiment of the present invention, in step (1), the chili peppers are selected from chili pepper varieties with a color value ≥ 150 and a spiciness ≤ 0.5%.

[0017] Further, in a preferred embodiment of the present invention, in step (1), the chili pepper varieties include Jinta chili peppers, Yidu red chili peppers, Zunyi chili peppers in Guizhou, and Huaxi chili peppers.

[0018] The beneficial effects of a method for extracting oleoresin from chili peppers provided by the present invention are as follows: (1) For the method for extracting oleoresin from chili peppers provided by the present invention, a gradient variable-temperature extraction technique is adopted. In the low-temperature section of extraction, free capsanthin is preferentially extracted, then in the medium-temperature section, the release of bound pigments is promoted, and then in the cooling section, the dissolution of capsaicin is inhibited. Under the above technical conditions, the extraction rate of capsanthin can be significantly increased, and at the same time, the content of capsaicin is significantly inhibited. This technology can effectively separate components with different solubilities in chili peppers, avoiding the problems of incomplete extraction or component damage caused by improper temperature selection in traditional constant-temperature extraction, and thus obtaining high-purity and high-quality oleoresin.

[0019] (2) For the method for extracting oleoresin from chili peppers provided by the present invention, based on the gradient variable-temperature extraction technique, a triple enhancement mechanism is adopted: that is, the synergistic effect of entrainer + ultrasonic + gradient variable temperature.

[0020] The non-polar solvent entrainer n-hexane has a polarity match with capsanthin and oleoresin in chili peppers, which is beneficial to improving the purity of capsanthin in oleoresin. The cavitation effect, mechanical effect, and thermal effect of ultrasonic waves can accelerate the diffusion of oleoresin from chili raw materials into supercritical CO2 fluid, improve the mass transfer efficiency. At the same time, the ultrasonic action can destroy the cell structure of chili peppers, making oleoresin easier to be extracted. On the premise of ensuring high purity of oleoresin, the extraction rate is significantly increased, and the practicability and economy of the process are enhanced.

[0021] The combination of the three can significantly improve the purity of capsanthin in oleoresin and the yield of oleoresin.

[0022] (3) For the method for extracting oleoresin from chili peppers provided by the present invention, a three-stage separation technique is adopted, which can achieve the efficient separation of capsanthin from capsaicin and wax: Through the multi-stage separation technique, according to the solubility differences of capsanthin, oleoresin, and impurities at different temperatures and pressures, the precise separation of the extraction product is realized. Among them, in the first-stage separation, capsanthin and most of the oil can be collected; in the second-stage separation process, capsanthin is enriched and part of the wax is separated; in the third-stage separation process, capsanthin is further purified and the residual solvent is removed. The multi-stage separation technique under the specific technical conditions provided in this application can effectively remove impurities in oleoresin and improve the purity and quality of oleoresin.

[0023] In summary, based on the above series of improvement measures of the supercritical CO2 extraction method, the present application synergistically acts from multiple dimensions, effectively improving the purity of capsanthin in oleoresin capsici and the yield of oleoresin capsici. It can achieve efficient, green, and precise extraction of capsanthin, significantly improve product quality and market competitiveness, and promote the high-end development of the deep processing industry of peppers. It has significant economic and social benefits. Detailed implementation manners

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Those not specified in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer. Those reagents or instruments not specified by the manufacturer can all be obtained as conventional products through commercial purchase.

[0025] The following specifically describes a method for extracting oleoresin capsici from peppers provided by an embodiment of the present invention.

[0026] A method for extracting oleoresin capsici from peppers includes: (1) Raw material pretreatment: Soak the peppers in ethanol with a concentration of 50% at 40°C for 30 min. Under the above conditions, most of the free capsaicin can be filtered out, and then hot air drying is carried out until the moisture content ≤ 6% to reduce the interference of moisture on the subsequent CO2 extraction performance. After drying, it is crushed to obtain chili powder with a particle size of 0.4 - 0.85 mm. Too fine particle size will increase the exposed area of capsaicin, resulting in co-extraction; too coarse will reduce the pigment extraction efficiency.

[0027] (2) Supercritical extraction: After heating the CO2 fluid to 35°C, add n-hexane to the CO2 fluid according to 4 - 6% of the volume of the CO2 fluid, and mix it in a static mixer and reserve. N-hexane is a non-polar solvent and has stronger selectivity for carotenoids.

[0028] Install an ultrasonic transducer on the inner wall of the extraction kettle. The working frequency of the ultrasonic transducer is 20 kHz, and the power density is set to 0.3 - 0.5 W / cm², and ultrasonic waves are applied in the first 30 min of extraction. Under the above conditions, the ultrasonic cavitation effect breaks the cell wall, improving the mass transfer rate, and applying ultrasonic waves in the first 30 min of extraction and then using conventional extraction later, with small total energy consumption.

[0029] Control the internal pressure of the extraction kettle to be 15 - 20 Mpa. Under this pressure, CO2 mainly dissolves weakly polar carotenoids, while polar components such as capsaicin remain in the residue. The ratio of the volume of the CO2 fluid mixed with n - hexane to the amount of chili powder used is 15 - 25 L:1 kg. This dosage can extend the contact time and improve selectivity. Extract at 34 - 36 °C for 29 - 31 min, then heat up to 39 - 41 °C and extract for 29 - 31 min, and then cool down to 36 - 38 °C and extract for 29 - 31 min to obtain a mixed fluid. In this application, the temperature range is controlled at 34 - 41 °C, which can inhibit the dissolution of capsaicin and prevent the thermal degradation of capsanthin at the same time.

[0030] In this application, free - state capsanthin is preferentially extracted in the low - temperature stage, then bound - state pigments are promoted to be released in the medium - temperature stage, and then the dissolution of capsaicin is inhibited in the cooling stage. Under the above technical conditions, the extraction rate of capsanthin can be significantly improved, and the content of capsaicin can be significantly inhibited at the same time.

[0031] (3) After the extraction is completed, the mixed fluid enters the separation kettle and is separated by multiple stages: First - stage separation: Set the pressure to 8 - 10 MPa and the temperature to 40 - 45 °C. Second - stage separation: Set the pressure to 5 - 6 MPa and the temperature to 30 - 35 °C. Third - stage separation: Set the pressure to 2 - 3 MPa and the temperature to 20 - 25 °C. Under the above conditions, capsanthin and most of the oil can be collected in the first - stage separation. The second - stage separation process enriches capsanthin and separates part of the wax. The third - stage separation process further purifies capsanthin and removes the residual solvent. The precipitated oleoresin is separated and collected through a filter screen, and then vacuum - deodorized and filtered and refined to obtain the finished product.

[0032] The features and properties of the present invention are further described in detail below in conjunction with the embodiments.

[0033] Example 1 This example provides a method for extracting oleoresin from chili peppers, including: (1) Raw material pretreatment: Remove impurities and wash 100 kg of Yidu red chili peppers, then dry them with hot air until the moisture content ≤ 6%, and then crush them to obtain chili powder with a particle size of 0.4 - 0.85 mm.

[0034] (2) Supercritical extraction: Control the internal pressure of the extraction kettle to be 18 Mpa, introduce the CO2 fluid, and the ratio of the volume of the CO2 fluid to the amount of chili powder used is 20 L:1 kg. Extract at 35 °C for 30 min, then heat up to 40 °C and extract for 30 min, and then cool down to 37 °C and extract for 30 min to obtain a mixed fluid.

[0035] After the extraction is completed, the mixed fluid enters the separation kettle and is separated at a pressure of 9 MPa and a temperature of 42°C for 2 hours. The extracted oleoresin is separated and collected through a filter screen, and then undergoes vacuum deodorization and filtration refinement to obtain the finished product.

[0036] Example 2 This example provides a method for extracting oleoresin from peppers. The difference from Example 1 is as follows: Step (2) Supercritical extraction: Control the internal pressure of the extraction kettle to be 15 Mpa, introduce CO2 fluid, and the ratio of the volume of CO2 fluid to the amount of chili powder used is 15 L: 1 kg. Extract at 34°C for 31 minutes, then raise the temperature to 39°C and extract for 30 minutes, and then lower the temperature to 36°C and extract for 29 minutes to obtain the mixed fluid.

[0037] Example 3 This example provides a method for extracting oleoresin from peppers. The difference from Example 1 is as follows: Step (2) Supercritical extraction: Control the internal pressure of the extraction kettle to be 20 Mpa, introduce CO2 fluid, and the ratio of the volume of CO2 fluid to the amount of chili powder used is 25 L: 1 kg. Extract at 36°C for 29 minutes, then raise the temperature to 41°C and extract for 30 minutes, and then lower the temperature to 38°C and extract for 31 minutes to obtain the mixed fluid.

[0038] Example 4 This example provides a method for extracting oleoresin from peppers. The difference from Example 1 is as follows: Step (2) Supercritical extraction: Install an ultrasonic transducer on the inner wall of the extraction kettle. The working frequency of the ultrasonic transducer is 20 kHz, and the power density is set to 0.4 W / cm². Apply ultrasonic waves in the first 30 minutes of extraction.

[0039] Example 5 This example provides a method for extracting oleoresin from peppers. The difference from Example 1 is as follows: Step (2) Supercritical extraction: Install an ultrasonic transducer on the inner wall of the extraction kettle. The working frequency of the ultrasonic transducer is 20 kHz, and the power density is set to 0.3 W / cm². Apply ultrasonic waves in the first 30 minutes of extraction.

[0040] Example 6 This example provides a method for extracting oleoresin from peppers. The difference from Example 1 is as follows: Step (2) Supercritical extraction: Install an ultrasonic transducer on the inner wall of the extraction kettle. The working frequency of the ultrasonic transducer is 20 kHz, and the power density is set to 0.5 W / cm². Apply ultrasonic waves in the first 30 minutes of extraction.

[0041] Example 7 This embodiment provides a method for extracting oleoresin from chili peppers, which is different from Embodiment 4 in that: Step (2) Supercritical extraction: Add n-hexane to the CO2 fluid according to 5% of the volume of the CO2 fluid, and reserve it after mixing in a static mixer.

[0042] Embodiment 8 This embodiment provides a method for extracting oleoresin from chili peppers, which is different from Embodiment 4 in that: Step (2) Supercritical extraction: Add n-hexane to the CO2 fluid according to 4% of the volume of the CO2 fluid, and reserve it after mixing in a static mixer.

[0043] Embodiment 9 This embodiment provides a method for extracting oleoresin from chili peppers, which is different from Embodiment 4 in that: Step (2) Supercritical extraction: Add n-hexane to the CO2 fluid according to 6% of the volume of the CO2 fluid, and reserve it after mixing in a static mixer.

[0044] Embodiment 10 This embodiment provides a method for extracting oleoresin from chili peppers, which is different from Embodiment 7 in that: Step (2) Supercritical extraction: After heating the CO2 fluid to 35 °C, add n-hexane to the CO2 fluid according to 5% of the volume of the CO2 fluid, and reserve it after mixing in a static mixer.

[0045] Embodiment 11 This embodiment provides a method for extracting oleoresin from chili peppers, which is different from Embodiment 10 in that: Step (3) Supercritical extraction: After the extraction is completed, the mixed fluid enters the separation kettle and adopts multi-stage separation: Primary separation: Set the pressure to 8 MPa and the temperature to 40 °C, and separate for 1 h; Secondary separation: Set the pressure to 5 MPa and the temperature to 30 °C, and separate for 0.5 h; Tertiary separation: Set the pressure to 2 MPa and the temperature to 20 °C, and separate for 0.5 h; The precipitated oleoresin is separated and collected through a filter screen, and then subjected to vacuum deodorization and filtration refinement to obtain the finished product.

[0046] Embodiment 12 This embodiment provides a method for extracting oleoresin from chili peppers, which is different from Embodiment 10 in that: Step (3) Supercritical extraction: After the extraction is completed, the mixed fluid enters the separation kettle and adopts multi-stage separation: Primary separation: Set the pressure to 10 MPa and the temperature to 45 °C, and separate for 1 h; Secondary separation: Set the pressure to 6 MPa and the temperature to 35 °C, and separate for 0.5 h; Tertiary separation: Set the pressure to 3 MPa and the temperature to 25 °C, and separate for 0.5 h; The precipitated oleoresin is separated and collected through a filter screen, and then subjected to vacuum deodorization and filtration refinement to obtain the finished product.

[0047] Embodiment 13 This embodiment provides a method for extracting oleoresin from chili peppers, which is different from Embodiment 10 in that: Step (1) Raw material pretreatment: 100 kg of chili peppers are soaked in ethanol with a concentration of 50% at 40 °C for 30 min, then dried with hot air until the moisture content ≤ 6%, and then crushed to obtain chili powder with a particle size of 0.4 - 0.85 mm.

[0048] Comparative Example 1 This comparative example provides a method for extracting oleoresin from chili peppers, including: (1) Raw material pretreatment: 100 kg of Yidu red chili peppers are removed of impurities, washed, dried with hot air until the moisture content ≤ 6%, and then crushed to obtain chili powder with a particle size of 0.4 - 0.85 mm.

[0049] (2) Supercritical extraction: The pressure in the extraction kettle is controlled at 25 Mpa, CO2 fluid is introduced, and the volume ratio of CO2 fluid to the amount of chili powder used is 20 L: 1 kg; extraction is carried out at 40 °C for 1.5 h to obtain a mixed fluid.

[0050] (3) After the extraction is completed, the mixed fluid enters the separation kettle, where separation is carried out at a pressure of 9 MPa and a temperature of 42 °C for 2 h; the precipitated oleoresin is separated and collected through a filter screen, and then subjected to vacuum deodorization and filtration refinement to obtain the finished product.

[0051] Comparative Example 2 This comparative example provides a method for extracting oleoresin from chili peppers, which is different from Embodiment 1 in that: Step (2) Supercritical extraction: The pressure in the extraction kettle is controlled at 25 Mpa, CO2 fluid is introduced, and the volume ratio of CO2 fluid to the amount of chili powder used is 10 L: 1 kg; extraction is carried out at 37 °C for 31 min, then the temperature is raised to 42 °C for 30 min, and then the temperature is lowered to 37 °C for 29 min to obtain a mixed fluid.

[0052] Experimental Example 1 Experimental method: Calculate the oleoresin yields provided in Examples 1 - 12 and Comparative Examples 1 - 2, and detect the capsanthin content, capsaicin content, and solvent residues in the oleoresins provided in Examples 1 - 12 and Comparative Examples 1 - 2. The results are shown in Table 1.

[0053] Calculation method for oleoresin yield: Oleoresin yield (%) = (mass of extracted oleoresin / mass of input chili raw materials) × 100% Detection method for capsanthin content: High performance liquid chromatography. Chromatographic conditions: C18 chromatographic column (250mm×4.6mm, 5μm); Mobile phase: Acetonitrile - water (85:15, V / V); Flow rate: 1.0mL / min; Detection wavelength: 470nm; Column temperature: 30°C; Injection volume: 20μL. Accurately weigh 0.1g of oleoresin capsici sample, dissolve it with acetonitrile and make up the volume to 10mL, filter it through a 0.45μm membrane and then determine it on the machine, and quantify it by the external standard method.

[0054] Detection method for capsaicin content: High performance liquid chromatography. Chromatographic column: C18 column (250mm×4.6mm, 5μm); Mobile phase: Methanol - water (70:30, V / V); Flow rate: 1.0mL / min; Detection wavelength: 280nm; Column temperature: 35°C; Injection volume: 10μL. Take 0.05g of oleoresin capsici sample, dissolve it with methanol and make up the volume to 5mL, filter it through a 0.45μm membrane and then inject it for analysis, and quantify it by the external standard method.

[0055] Detection method for solvent residue: Headspace gas chromatography. Chromatographic column: DB - 624 capillary column (30m×0.32mm×1.8μm); Injection port temperature: 200°C; Detector temperature: 250°C; Column temperature: Keep at 40°C for 2min, increase to 200°C at a rate of 10°C / min, and keep for 5min; Headspace sampler equilibrium temperature: 80°C, equilibrium time: 30min. Weigh 1g of oleoresin capsici sample, place it in a 20mL headspace vial, seal it and then detect it, and quantify it by the external standard method.

[0056] Table 1 Group number Yield of oleoresin capsici / % Content of capsanthin / % Content of capsaicin / % Solvent residue (mg / kg) Example 1 16.22％ 16.14％ 0.012％ 0.01 Example 2 16.04％ 15.86％ 0.015％ 0.01 Example 3 15.86％ 15.84％ 0.018％ 0.01 Example 4 19.25% 18.42% 0.009％ 0.01 Example 5 19.14% 18.01% 0.008％ 0.01 Example 6 19.09% 18.35% 0.008％ 0.01 Example 7 22.31% 21.66% 0.006% 0.01 Example 8 22.44% 21.05% 0.006% 0.01 Example 9 22.08% 20.98% 0.006% 0.01 Example 10 23.62% 22.45% 0.004% Not detected Example 11 25.08% 23.04% 0.002% Not detected Example 12 25.25％ 23.52％ 0.002% Not detected Comparative example 1 10.21％ 8.32％ 3.82％ 0.50 Example 2 14.32％ 13.52％ 0.120％ 0.05 It can be seen from the data in Table 1 that the method for extracting oleoresin capsici from chili peppers provided in Examples 1 - 12 of the present invention can obtain oleoresin capsici with a high yield, high purity of capsanthin, low capsaicin content, and almost no solvent residue.

[0057] In summary, by using the method for extracting oleoresin capsici from chili peppers provided by the present invention, oleoresin capsici with a high yield and rich in capsanthin can be obtained.

[0058] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for extracting oleoresin from chili peppers, characterized in that: (1) Raw material pretreatment: Dry the chili peppers and then crush them to obtain chili powder; (2) Supercritical extraction: Control the internal pressure of the extraction kettle at 15 - 20 Mpa, and the ratio of the volume of the CO2 fluid introduced to the amount of the chili powder used is 15 - 25 L:1 kg. Extract at 34 - 36 °C for 29 - 31 min, then raise the temperature to 39 - 41 °C and extract for 29 - 31 min, and then lower the temperature to 36 - 38 °C and extract for 29 - 31 min to obtain a mixed fluid; (3) After the extraction is completed, the mixed fluid enters the separation kettle, and the precipitated oleoresin is separated and collected through a filter screen, and then subjected to vacuum deodorization and filtration refinement to obtain the finished product.

2. The method for extracting oleoresin from capsicum according to claim 1, characterized in that: In step (2), before introducing the CO2 fluid into the extraction kettle, add n - hexane to the CO2 fluid at 4 - 6% of the volume of the CO2 fluid, mix it in a static mixer and then set aside.

3. The method for extracting oleoresin capsici from capsicum according to claim 2, characterized in that: In step (2), heat the CO2 fluid to 35 °C and then mix it with the n - hexane.

4. The method for extracting oleoresin from capsicum according to claim 1, wherein: In step (2), install an ultrasonic transducer on the inner wall of the extraction kettle. The working frequency of the ultrasonic transducer is 20 kHz, and the power density is set to 0.3 - 0.5 W / cm², and apply ultrasound in the first 30 min of extraction.

5. The method for extracting oleoresin capsici from chili peppers according to claim 1, characterized in that: In step (3), adopt multi - stage separation: First - stage separation: Set the pressure at 8 - 10 MPa and the temperature at 40 - 45 °C; Second - stage separation: Set the pressure at 5 - 6 MPa and the temperature at 30 - 35 °C; Third - stage separation: Set the pressure at 2 - 3 MPa and the temperature at 20 - 25 °C.

6. The method for extracting oleoresin from capsicum according to claim 1, wherein: In step (1), the particle size of the chili powder is 0.4 - 0.85 mm.

7. The method for extracting oleoresin from capsicum according to claim 1, characterized in that: In step (1), the chili peppers are dried by hot air until the moisture content ≤ 6%.

8. The method for extracting oleoresin from capsicum according to claim 1, characterized in that: In step (1), before drying, the chili peppers are pretreated to remove spiciness: soak the chili peppers in ethanol with a concentration of 50% at 40 °C for 30 min, filter and then dry.

9. The method for extracting oleoresin from capsicum according to claim 1, characterized in that: In step (1), the chili peppers are selected from chili pepper varieties with a color value ≥ 150 and a spiciness ≤ 0.5%.

10. The method for extracting oleoresin capsici from capsicum according to claim 9, characterized in that: In step (1), the chili pepper varieties include Jinta chili peppers, Yidu red chili peppers, Guizhou Zunyi chili peppers, and Huaxi chili peppers.