Method for extracting lycium ruthenicum anthocyanin through supercritical CO2 and application of lycium ruthenicum anthocyanin

Abstract

The invention provides a method for extracting anthocyanidin from lycium ruthenicum by using supercritical CO2, which optimizes the extraction temperature, pressure, time and entrainer to improve the extraction rate and purity of anthocyanidin. Through the analysis of a high performance liquid chromatography (HPLC), the main component in the extract is confirmed to be petunidin-3-rutinoside (trans-p-coumaroyl)-5-O-glucoside. The method can effectively improve the extraction efficiency of the lycium ruthenicum anthocyanin and maintain the biological activity of the lycium ruthenicum anthocyanin, and is suitable for the fields of foods, medicines and cosmetics.

Description

Technical Field

[0001] The present invention relates to the technical field of natural product extraction, and particularly relates to a method for extracting anthocyanins from Lycium ruthenicum Murray by supercritical CO2 extraction and its application. Background Art

[0002] Lycium ruthenicum Murray, namely black wolfberry, is a variety of Lycium chinense Miller. Its nature and flavor are sweet, bitter, and warm without toxicity. It has the effects of tonifying the liver and kidney, improving eyesight, moistening the lungs, and benefiting essence and blood. Lycium ruthenicum Murray is mild in nature and different from general warm drugs, suitable for people with different constitutions to consume. Lycium ruthenicum Murray is a traditional Chinese medicinal and edible homologous plant in China. Its fruits are rich in various active ingredients such as anthocyanins, polysaccharides, and flavonoids, and have various pharmacological activities such as antioxidant, anti-fatigue, hypoglycemic, and hypolipidemic effects. Anthocyanins are one of the most important active ingredients in Lycium ruthenicum Murray and belong to flavonoids in phenolic compounds, with extremely strong antioxidant ability. Research shows that the anthocyanin types in Lycium ruthenicum Murray mainly include petunidin, delphinidin, and malvidin, among which petunidin accounts for 95% of the total anthocyanin content and is its main active ingredient. Anthocyanins in Lycium ruthenicum Murray can enhance the immune activity of the body, improve the immune ability, and have various effects such as anti-allergy, antibacterial, and anti-aging effects. As a natural antioxidant, anthocyanins in Lycium ruthenicum Murray have broad application prospects. They can not only be used as nutritional fortifiers and food additives in the food industry, but also be used to develop functional foods and drugs. With the increasing demand for healthy foods by consumers, the research on the extraction and application of anthocyanins in Lycium ruthenicum Murray has received more and more attention. However, due to the sensitivity of anthocyanins to environmental factors such as heat, light, acid, and alkali, traditional extraction methods such as water extraction and solvent extraction may cause partial degradation of them, thereby reducing their activity and stability. Therefore, developing efficient and environmentally friendly anthocyanin extraction technologies is of great significance for making full use of this natural resource and enhancing its economic value. Among them, supercritical CO2 extraction technology, as an efficient, environmentally friendly technology that can well protect the biological activity of target products, has received wide attention.

[0003] In recent years, due to its advantages such as low operating temperature, no solvent residue, and good selectivity, supercritical fluid extraction technology (SFE) has gradually become one of the preferred technologies for the extraction of thermosensitive natural products. Among them, supercritical CO2 extraction technology, as a typical representative of SFE, has received extensive attention and application due to its environmental friendliness and application advantages in the extraction of anthocyanins. Compared with several traditional extraction methods, such as water extraction method, ultrasonic-assisted extraction method, and microwave-assisted extraction method, supercritical CO2 extraction technology shows significant advantages in many aspects. First of all, it can carry out extraction at low temperature, avoiding the degradation of anthocyanins due to high temperature, thereby improving the extraction efficiency and product quality. Secondly, as an inert gas, supercritical CO2 will not remain in the product, ensuring the safety of the product and avoiding the health risks brought by organic solvent residues. In addition, supercritical CO2 can selectively separate according to the solubility differences between anthocyanins and other components, improving the extraction efficiency and obtaining products with higher purity. Finally, as a green solvent, supercritical CO2 can be completely recycled after use, leaving almost no residues, which is environmentally friendly and meets the requirements of sustainable development of modern industry. Yan Xueqin et al. optimized the supercritical CO2 extraction process for proanthocyanidins in pomegranate peel, and the final optimal process conditions were an extraction temperature of 48 °C, an extraction pressure of 35 MPa, and an entrainer of 65% ethanol. At this time, the extraction rate of proanthocyanidins could reach 3.40%; Liu Wenyu et al. optimized the process conditions for the extraction of proanthocyanidins from grape seeds by supercritical CO2 using the response surface method, and determined the optimal parameters as an extraction temperature of 55 °C, an extraction pressure of 35 MPa, and an entrainer of 69.22% ethanol. Under these conditions, the yield of proanthocyanidins reached 163.60 mg / kg, and the purity was as high as 88.5%; Maran et al. used the Box-Behnken response surface design method to study the influencing factors of supercritical CO2 extraction of total anthocyanins and phenolic compounds in the pulp of Indian blackberry (Syzygium cumini L., Skeels), including pressure, temperature, and co-solvent flow rate, and determined the optimal conditions as a pressure of 162 bar, a temperature of 50 °C, and a co-solvent flow rate of 2.0 g / min.

[0004] In summary, although supercritical CO2 extraction technology has been extensively studied in the extraction of anthocyanins from other plants, such as pomegranate peel, grape seeds, blackberries, and blackcurrants, the research on supercritical CO2 extraction of anthocyanins from Lycium ruthenicum Murr. is still relatively limited, lacking systematic process optimization and component analysis. This has restricted the efficient extraction and industrial application of anthocyanins from Lycium ruthenicum Murr. In this paper, by systematically optimizing the supercritical CO2 extraction process, the extraction efficiency of anthocyanins from Lycium ruthenicum Murr. is improved, and heat-sensitive components are protected under low-temperature conditions to develop an efficient and environmentally friendly anthocyanin extraction technology, ensuring the biological activity and flavor characteristics of the extract, providing technical support for the industrial application of Lycium ruthenicum Murr., promoting the development of related products, and better meeting people's demand for healthy foods. Summary of the Invention

[0005] The object of the present invention is to provide an optimized supercritical CO2 extraction method, which can improve the extraction rate of anthocyanins from Lycium ruthenicum Murr. at a lower temperature and under optimized conditions, while maintaining its structural stability.

[0006] Therefore, on the one hand, the present invention discloses a method for extracting anthocyanins from Lycium ruthenicum Murr. by supercritical CO2, and the method comprises the following steps:

[0007] (1) Take the dried fruits of Lycium ruthenicum Murr., crush them and pass through a 30-mesh sieve to obtain fine powder;

[0008] (2) Load the obtained fine powder into the extraction kettle of the supercritical extraction device;

[0009] (3) Under the conditions that the CO2 flow rate is 13 L / h, the extraction temperature is 35 °C, the extraction pressures are 15 MPa, 20 MPa, and 30 MPa respectively, and the extraction times are 55 min, 100 min, and 120 min respectively, add an entrainer at 33%-37% of the feeding amount for supercritical CO2 extraction, wherein the entrainer is 0.3% glacial acetic acid, 1% formic acid water or ethanol-citric acid solution, and the volume ratio of the ethanol-citric acid solution is 60% ethanol:10% citric acid = 3:7;

[0010] (4) After the extraction is completed, the anthocyanins are separated in the separation kettle, and the collected extract is the anthocyanin extract.

[0011] Preferably, the extraction pressure in step (3) of the present invention is preferably 20 MPa.

[0012] Preferably, the extraction time in step (3) of the present invention is preferably 55 min

[0013] Preferably, the entrainer in step (3) of the present invention is preferably 0.3% glacial acetic acid.

[0014] Preferably, the anthocyanin extract in step (4) of the present invention is detected by HPLC, and the main component is petunidin-3-rutinoside (trans-p-coumaroyl)-5-O-glucoside.

[0015] In one aspect, the present invention also discloses an application of the above method in the supercritical CO2 extraction of black goji berry anthocyanins.

[0016] The beneficial effects of the present invention are summarized as follows:

[0017] (1) Improve the extraction rate: Under the optimized extraction conditions, the highest extraction rate of anthocyanins can reach 0.071 mg / 100 g.

[0018] (2) Maintain activity: Compared with the traditional solvent extraction method, supercritical CO2 extraction avoids high-temperature treatment, reduces the thermal degradation of anthocyanins, and improves their biological activity.

[0019] (3) Green and environmentally friendly: Using CO2 as a solvent, there is no residue of organic solvents, meeting the standards of the food and pharmaceutical industries.

[0020] (4) Wide applicability: The obtained anthocyanins can be applied to the food, pharmaceutical, and cosmetic industries, and have antioxidant, anti-aging, and immunomodulatory effects.

[0021] In summary, the present invention provides an efficient and green method for extracting black goji berry anthocyanins, which can be widely applied to the development fields of functional foods, pharmaceuticals, and cosmetics, and has important commercial value and application prospects. Brief Description of the Drawings

[0022] Figure 1 Schematic diagram of the process of the supercritical CO2 extraction device.

[0023] Figure 2 Schematic diagram of the principle of the supercritical CO2 extraction experiment. Note: a - CO2 gas cylinder, b - purifier, c - condenser, d - mixer, e - purifier, f - extraction kettle, g - separation kettle Ι, h - separation kettle ΙΙ.

[0024] Figure 3 Effect of extraction time on the extraction rate of anthocyanins.

[0025] Figure 4 Effect of extraction pressure on the extraction rate of anthocyanins.

[0026] Figure 5 Effect of entrainer on the extraction rate of anthocyanins.

[0027] Figure 6 HPLC chromatogram of the reference substance.

[0028] Figure 7 HPLC spectrum of the supercritical CO2 extract. Detailed implementation manners

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this invention belongs. The terms used in the description of the present invention herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the related listed items.

[0030] Unless otherwise specified, the reagents, methods, and equipment used in this invention are conventional reagents, methods, and equipment in this technical field. Unless otherwise specified, the reagents and materials used in the following examples are all commercially available.

[0031] Example 1: Process for extracting anthocyanins from Lycium ruthenicum Murr. by supercritical CO2 extraction and component analysis thereof

[0032] 1. Purpose

[0033] To extract anthocyanins from Lycium ruthenicum Murr. by supercritical CO2 extraction method and perform component analysis on the extracted anthocyanins.

[0034] 2. Materials and methods

[0035] 2.1 Materials and reagents

[0036] Lycium ruthenicum Murr. (purchased from the core production area of the Qaidam Basin in Haixi Mongol and Tibetan Autonomous Prefecture, Qinghai Province, and identified as Lycium ruthenicum Murray.inComment.Soc.Sc.Gotting by Researcher Li Yulin of the Northwest Institute of Plateau Biology, Chinese Academy of Sciences); Petunidin-3-rutinoside (trans-p-coumaroyl)-5-O-glucoside (CAS No. 106863-71-2, Shanghai Standard Technology Service Co., Ltd.); Citric acid monohydrate (Jiahe Food Industry Co., Ltd.; reagents such as anhydrous ethanol, ethanol, acetonitrile, and formic acid are all of analytical grade or chromatographic grade).

[0037] 2.2 Instruments and equipment

[0038] Supercritical extraction device ((HA221-50-06-C type, Hangzhou Dongcui Technology Co., Ltd.); High-speed traditional Chinese medicine grinder (150B swing type, Ruian Yongli Pharmaceutical Machinery Co., Ltd., Zhejiang Province); High-performance liquid chromatograph (Shimadzu, FY-YX-011); Electronic balance (Mettler Toledo, HQ-DT-010); Ultrasonic cleaner (Jiangsu Kunshan Ultrasonic Instruments); Ultra-pure water instrument (Millipore, QT-CC-001).

[0039] 2.3 Methods

[0040] 2.3.1 Extraction of Anthocyanins

[0041] In this study, supercritical CO2 extraction technology was used to extract anthocyanins from Lycium ruthenicum Murr. The schematic diagram of the device process is as Figure 1 shown. First, the fruits of Lycium ruthenicum Murr were crushed and passed through a 30-mesh sieve. After obtaining the fine powder, a certain amount was weighed and reserved. Subsequently, the pretreated sample was placed in the extraction kettle of the supercritical extraction device, and the experimental principle is as Figure 2 shown. The CO2 flow rate was set at 13 L / h, the extraction temperature was 35 °C, the extraction pressure was adjusted according to the experimental design (15 MPa, 20 MPa, 30 MPa), and the extraction times were 55 min, 100 min, and 120 min respectively. The entrainers were 1% formic acid water, 0.3% glacial acetic acid, and a mixed solution of 60% ethanol and 10% citric acid. After extraction, the anthocyanins were separated in the separation kettle, and the extract was collected for subsequent analysis.

[0042] 2.3.2 Preparation of Standard Solution

[0043] In this study, petunidin-3-rutinoside (trans-p-coumaroyl)-5-O-glucoside was selected as the reference substance because it accounted for 86% of petunidin anthocyanins and had a clear structure. A certain amount of petunidin reference substance was weighed and prepared into a standard solution with a concentration of 0.1 mg / mL using 1% formic acid water for HPLC detection.

[0044] 2.3.3 HPLC Chromatographic Conditions

[0045] Chromatographic column: YMC-Triart C18 (4.6 * 250 nm, 5 μm); Column temperature: 30 °C; Detector: 290 nm; Injection volume: 20 μL. The gradient elution conditions are shown in Table 1.

[0046] Table 1 Mobile Phase Gradient Elution Conditions

[0047]

[0048] 3. Results and Analysis

[0049] 3.1 Influence of Extraction Time

[0050] A certain amount of sample was weighed, and under the conditions of 1% formic acid water as the entrainer, a CO2 flow rate of 13 L / h, an extraction temperature of 35 °C, and an extraction pressure of 30 MPa, the influence of different extraction times (55 min, 100 min, 150 min) on the extraction rate of anthocyanins was studied. The results are shown in Figure 3 .

[0051] FromFigure 3 It can be seen that with the extension of the extraction time, the extraction rate of anthocyanins first increases and then decreases. When the extraction time is 55 min, the extraction rate of anthocyanins is the highest, reaching 0.025 mg / 100 g. When the extraction time is extended to 120 min, the extraction rate drops to 0.002 mg / 100 g. This indicates that too long extraction time may lead to thermal degradation or structural damage of anthocyanins.

[0052] 3.2 Influence of extraction pressure

[0053] A certain amount of sample was weighed, and under the conditions of entrainer being 1% formic acid water, CO2 flow rate being 13 L / h, extraction temperature being 35 °C, and extraction time being 55 min, the influence of different extraction pressures (15 MPa, 20 MPa, 30 MPa) on the extraction rate of anthocyanins was studied. The results are shown in Figure 4 .

[0054] It can be Figure 4 seen that with the increase of the extraction pressure, the extraction rate of anthocyanins shows a trend of first increasing and then decreasing. When the extraction pressure is 20 MPa, the extraction rate of anthocyanins is the highest, reaching 0.028 mg / 100 g. When the pressure increases to 30 MPa, the extraction rate drops to 0.025 mg / 100 g. This indicates that appropriate pressure can improve the solubility of anthocyanins, but too high pressure may lead to changes in solvent density and affect the extraction efficiency.

[0055] 3.3 Influence of entrainer

[0056] A certain amount of sample was weighed, and under the conditions of CO2 flow rate being 13 L / h, extraction temperature being 35 °C, extraction time being 55 min, and extraction pressure being 20 MPa, the influence of different entrainers on the extraction rate of anthocyanins was studied. They were 1# (1% formic acid water), 2# (0.3% glacial acetic acid), and 3# (mixed solution of 60% ethanol and 10% citric acid, where the volume ratio of ethanol - citric acid solution is 60% ethanol:10% citric acid = 3:7). The results are shown in Figure 5 .

[0057] It can be Figure 5 seen that different entrainers have a significant influence on the extraction rate of anthocyanins. When using 0.3% glacial acetic acid as the entrainer, the extraction rate of anthocyanins is the highest, reaching 0.071 mg / 100 g. The extraction rates of 1% formic acid water and the mixed solution of 60% ethanol and 10% citric acid are 0.025 mg / 100 g and 0.019 mg / 100 g respectively. This indicates that using 0.3% glacial acetic acid as the entrainer can significantly improve the solubility of anthocyanins, thereby improving the extraction efficiency.

[0058] 3.4 HPLC chromatographic analysis

[0059] To verify the compositional characteristics of anthocyanins from Lycium ruthenicum Murr. obtained by supercritical CO2 extraction, high performance liquid chromatography was used to conduct a comparative analysis of the reference substance (petunidin-3-rutinoside (trans-p-coumaroyl)-5-O-glucoside) and the sample. As Figure 6 shown, the reference substance presented a single and sharp chromatographic peak at a detection wavelength of 290 nm, with a retention time of 18.003 min, a peak area of 3363493, a peak height of 367773 mAU, and both the area ratio and peak height ratio being 100%, indicating that the reference substance had extremely high purity and no interference from coexisting impurities. The HPLC chromatogram of the sample ( Figure 7 ) showed that the retention time of the main peak was 18.005 min (ΔRet.Time = 0.002 min), which was highly consistent with the retention time of the reference substance (RSD < 0.01%), confirming that the two were the same target compound.

[0060] However, the peak area of the sample was 273785 and the peak height was 27778 mAU, significantly lower than those of the reference substance, only 8.14% and 7.55% of the reference substance, respectively. This difference may be due to the following reasons: In the supercritical CO2 extraction process, although the pressure (20 MPa), time (55 min), and entrainer (0.3% glacial acetic acid) were optimized, the complexity of the sample matrix may cause some anthocyanins to bind to polysaccharides or lipids, reducing their free-state concentration; trace amounts of thermosensitive anthocyanins may degrade due to local temperature fluctuations in the separation kettle during the extraction process; sample pretreatment (crushing, sieving) may introduce mechanical shear force, affecting the stability of the target substance. It should be noted that no other impurity peaks were detected in the sample chromatogram (NTP value was 70272), indicating that within the detection range of the target substance (15 min - 35 min), the extract had high purity, and the supercritical CO2 technology effectively avoided the common co-extraction interference phenomenon in traditional solvent extraction.

[0061] In addition, by comparing the gradient elution condition Table 1 with the analysis method of petunidin compounds reported in the literature, the chromatographic conditions in this experiment (YMC-Triart C18 column, acetonitrile-formic acid water mobile phase) had good separation and reproducibility. The research results further verified the applicability of the supercritical CO2 extraction technology combined with HPLC method in the qualitative and quantitative analysis of anthocyanins from Lycium ruthenicum Murr., laying a foundation for subsequent mass spectrometry identification and industrial quality control.

[0062] 4. Conclusion

[0063] Through supercritical CO2 extraction technology combined with HPLC analysis, this study systematically optimized the extraction process of anthocyanins from Lycium ruthenicum Murr. and verified its component characteristics. Experiments showed that under the optimal conditions (20 MPa, 55 min, 0.3% glacial acetic acid), the extraction rate of anthocyanins could reach 0.071 mg / 100 g, and the HPLC chromatogram showed that the retention time of the target substance (18.005 min) was highly consistent with that of the reference substance (RSD < 0.01%), confirming the structural integrity and high purity of the extract (NTP > 70,000). Through comprehensive comparison and in-depth analysis, the method of supercritical CO2 extraction of anthocyanins from Lycium ruthenicum Murr. adopted in this study showed significant advantages in multiple key indicators. There was no report in the existing literature on the use of the specific combination of extraction temperature of 35 °C, pressure of 20 MPa, time of 55 min, and 0.3% glacial acetic acid entrainer for the extraction of anthocyanins from Lycium ruthenicum Murr. This combination was ingeniously selected and had outstanding creativity and synergistic effects:

[0064] (1) Synergistic optimization of parameters: The low temperature of 35 °C avoided the thermal degradation of anthocyanins. Acting synergistically with the pressure of 20 MPa, it made the solubility of CO2 in anthocyanins reach the best. At the same time, the extraction time of 55 min precisely balanced the extraction efficiency and the retention of activity. The parameters cooperated with each other to form an efficient and mild extraction environment.

[0065] (2) Synergistic effect of the entrainer: The 0.3% glacial acetic acid entrainer not only significantly increased the solubility of anthocyanins and enhanced the extraction efficiency, but also its acidic environment helped to stabilize the structure of anthocyanins and prevent chemical changes during the extraction process, complementing the characteristics of supercritical CO2 and jointly ensuring the high purity and high activity of the extract.

[0066] (3) Green sustainability: There was no residue of organic solvents in the whole process, and CO2 could be recycled, perfectly meeting the current concepts of green chemistry and sustainable development, and greatly reducing environmental pollution and production costs compared with traditional methods.

[0067] In summary, supercritical CO2 technology effectively avoided the thermal degradation and organic pollution of anthocyanins through the advantages of low temperature and no solvent residue, providing a green solution for industrial production. However, the low concentration of the target substance in the sample (the peak area was only 8.14% of that of the reference substance) indicated that it was necessary to further optimize the proportion of the entrainer or introduce a dynamic extraction mode to improve the recovery rate. Future research could explore its stability and bioavailability in functional foods. This achievement not only provided a theoretical basis for the high-value utilization of Lycium ruthenicum Murr. resources, but also opened up a new path for the innovation and industrial application of natural pigment extraction technology.

[0068] Example 2: Supercritical CO2 Extraction vs Traditional Solvent Extraction of Anthocyanins from Lycium ruthenicum Murr.

[0069] 1. Purpose

[0070] By comparing various key indicators of the supercritical CO2 extraction method and the traditional ethanol extraction method in the process of extracting anthocyanins from Lycium ruthenicum Murr., the significant advantages of the supercritical CO2 extraction method are demonstrated.

[0071] 2. Supercritical CO2 Extraction Method of Anthocyanins from Lycium ruthenicum Murr. vs Traditional Ethanol Extraction Method

[0072] To better demonstrate the superiority of the supercritical CO2 extraction technology in extracting anthocyanins from Lycium ruthenicum Murr., the following comparison table is based on the data of Liu Zhenhua et al. on extracting anthocyanins from Lycium ruthenicum Murr. with 70% ethanol and has been analyzed in detail.

[0073] Table 2 Supercritical CO2 Extraction vs Traditional Ethanol Extraction

[0074]

[0075] 3. Results and Analysis

[0076] 3.1 Yield and Efficiency: The traditional solvent method (such as ethanol extraction) has a higher yield (0.424%), but requires high temperature (55°C) and long time (2.5 h), which is prone to thermal degradation of anthocyanins (such as demethylation by-products). The supercritical CO2 method has a lower yield (0.071 mg / 100 g), but the low-temperature (35°C) operation can completely avoid thermal degradation, and the efficiency and active retention can be balanced through the optimization of the dynamic extraction mode (such as gradient pressure adjustment).

[0077] 3.2 Purity and Safety: The extract obtained by supercritical CO2 extraction was detected by HPLC. The retention time difference of the reference substance was extremely small (ΔRT < 0.002 min), and there were no co-extracted impurity peaks (NTP > 70,000) within the target detection range (15 min - 35 min), indicating that the purity of the extract was extremely high. However, the traditional ethanol extraction method is likely to introduce some impurities during the extraction process due to the use of organic solvents, and the high-temperature conditions may cause the degradation of anthocyanins, resulting in impurity peaks such as cyanidin derivatives. Therefore, the extracts obtained by the traditional method usually require additional desolvation and purification steps to improve the product purity, which not only increases the production cost but also may further lose the activity of anthocyanins.

[0078] 3.3 Environmental friendliness and cost: The supercritical CO2 extraction technology uses the inert gas CO2 as a solvent, and there is no problem of residual organic solvents in the whole extraction process. Moreover, CO2 can be recycled, greatly reducing the production cost and environmental pollution. This characteristic makes it fully conform to the concepts of modern green chemistry and sustainable development, and has significant environmental protection advantages in industrial production. The traditional ethanol extraction method relies on a large amount of organic solvents such as ethanol. After extraction, the wastewater containing organic solvents needs to be treated, and at the same time, solvent recovery is also required to reduce costs and environmental pollution. These additional treatment steps not only increase the industrial cost, but also cause certain pressure on the environment.

[0079] 3.4 Industrialization potential: The supercritical CO2 extraction technology has good potential for industrial application. Taking the HA221-50-06-C type supercritical extraction device as an example, this technology can be directly scaled up to industrial-level equipment for production, without complex post-treatment processes, and can meet the demand for high-purity anthocyanin production. The traditional ethanol extraction method is limited to a certain extent in the process of large-scale application due to problems such as difficult solvent recovery and high energy consumption. For example, in large-scale production, the investment in solvent recovery equipment is large and the energy consumption is high, which not only increases the production cost, but also may affect the production efficiency and product quality.

[0080] 4. Conclusion

[0081] The supercritical CO2 extraction technology shows significant advantages in many aspects compared with the traditional ethanol extraction method in the extraction of anthocyanins from Lycium ruthenicum Murr. In terms of maintaining biological activity, the low-temperature operation of supercritical CO2 extraction effectively avoids the thermal degradation of anthocyanins and can better retain their biological activity; in terms of the purity of the extract, the product obtained by this technology has high purity and almost no impurities, while the traditional method requires additional purification steps; in terms of environmental friendliness, the CO2 used in supercritical CO2 extraction can be recycled and pollution-free, while the traditional method has problems of organic solvent pollution and high treatment costs; in terms of industrialization potential, the supercritical CO2 extraction technology is more easily scaled up for production. Although the extraction rate of the supercritical CO2 extraction method is slightly lower than that of the traditional method at present, through further optimization of the process, such as improving the proportion of entrainer and optimizing the extraction process, it is expected to further improve its extraction efficiency. Generally speaking, the supercritical CO2 extraction technology has great potential in the extraction and large-scale industrial production of anthocyanins from Lycium ruthenicum Murr., provides reliable technical support for the high-value utilization of anthocyanins from Lycium ruthenicum Murr., and also opens up a new direction for the development of related fields.

[0082] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A method for extracting anthocyanins from Lycium barbarum with supercritical CO2, characterized in that: The method comprises the following steps: (1) taking dried wolfberry fruits, crushing them and passing them through a 30-mesh sieve to obtain fine powder; (2) loading the obtained fine powder into an extraction kettle of a supercritical extraction device; (3) Under the conditions of CO2 flow rate of 13 L / h, extraction temperature of 35°C, extraction pressures of 15 MPa, 20 MPa, 30 MPa, and extraction times of 55 min, 100 min, and 120 min, an entrainer was added at 33%-37% of the feed amount to perform supercritical CO2 extraction, wherein the entrainer was 0.3% glacial acetic acid, 1% formic acid water, or ethanol-citric acid solution, wherein the volume ratio of the ethanol-citric acid solution was 60% ethanol:10% citric acid=3:7; (4) After the extraction is completed, anthocyanins are separated in a separation kettle, and the extract is collected as anthocyanin extract.

2. The method according to claim 1, characterized in that The extraction pressure in step (3) is preferably 20 MPa.

3. The method according to claim 1, characterized in that The extraction time in step (3) is preferably 55 min.

4. The method according to claim 1, characterized in that: The entrainer in step (3) is preferably 0.3% glacial acetic acid.

5. The method according to claim 1, characterized in that The anthocyanidin extract in step (4) is detected by HPLC, and the main component is petunidin-3-rutinoside-5-O-glucoside, wherein rutinoside contains an anti-p-coumaroyl structure.

6. Use of the method according to claim 1 in supercritical CO2 extraction of anthocyanins from Lycium ruthenicum.

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