Integrated processing technology for efficiently drying caulis spatholobi and enriching flavonoid components

Abstract

The invention discloses an integrated processing technology for efficiently drying caulis spatholobi and enriching flavonoid components. The integrated processing technology comprises the steps of raw material pretreatment, sectional type coupling drying, flavonoid component extraction and flavonoid component enrichment. The pretreatment adopts vacuum low-temperature pulse blasting; microwave and low-temperature hot air are combined for drying, and infrared radiation setting can be selected; a lactic acid-choline chloride water-containing eutectic solvent is adopted for extraction, and ultrasonic assistance is combined; and carrying out membrane filtration and gradient elution after enrichment. The method can improve the flavone extraction rate and purity, the extract meets preset component quality requirements, and the method has the characteristics of reasonable process and high efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of traditional Chinese medicinal material processing, in particular to an efficient drying and flavonoid component enrichment integrated processing technology of Spatholobi Caulis. BACKGROUND

[0002] Spatholobi Caulis is the dried stem of Spatholobi Caulis, a traditional Chinese medicine, which has the effects of activating blood and tonifying blood, regulating menstruation and relieving pain, and relaxing sinews and collaterals. Modern pharmacological studies have shown that the main bioactive substances of Spatholobi Caulis include flavonoids, phenolic acids, and sterols, among which flavonoids such as catechin and epicatechin are believed to be the key substance basis for its cardiovascular protection, antioxidant, and anti-inflammatory effects. Flavonoids have a basic skeletal structure of C6-C3-C6, and exist mainly in the form of flavones, flavonols, and catechins. They contain multiple phenolic hydroxyl groups in the molecule, have both fat-soluble and water-soluble characteristics, are easily complexed with metal ions, and are sensitive to heat, oxygen, and acid-base environment. High temperature or improper processing can easily cause structural isomerization and oxidative degradation, resulting in loss of activity. Therefore, during the production and deep processing of Spatholobi Caulis, how to efficiently and completely obtain and enrich these active ingredients is of great significance for ensuring the quality of medicinal materials, improving the added value of products, and promoting the development of related medicines and health products.

[0003] At present, the production and processing of Spatholobi Caulis still generally use natural air-drying or ordinary hot-air drying methods. Natural air-drying completely depends on weather conditions, has a long drying period, is easily polluted by the environment, and is not uniform in drying, which can easily lead to mold growth or enzymatic loss of active ingredients in medicinal materials. Although ordinary hot-air drying is not limited by weather, the drying temperature is usually high and the duration is long, which has the problems of low drying efficiency and high energy consumption. More importantly, flavonoids in Spatholobi Caulis are not stable to heat, and long-term high-temperature treatment can easily cause oxidation, degradation, or isomerization of flavonoids, resulting in irreversible loss of active ingredients and directly affecting the efficacy of the final product. In recent years, some new drying technologies such as vacuum freeze-drying and microwave drying have been tried to be applied to the processing of traditional Chinese medicinal materials. Vacuum freeze-drying can maximize the preservation of heat-sensitive components, but the equipment investment and operating cost are high, and the drying period is extremely long, which is difficult to adapt to large-scale industrial production. Although microwave drying is efficient, if not properly controlled, it can easily cause local charring or thermal damage to active ingredients due to instantaneous overheating of the material inside, and there is also the problem of uneven drying when used alone.

[0004] In the extraction of active ingredients, traditional methods often use water extraction or high-concentration organic solvent (such as ethanol, methanol) reflux extraction. Water extraction method has low cost and safety, but the extraction selectivity is poor, a large amount of impurities such as polysaccharide and protein are dissolved, which brings great difficulty to subsequent separation and purification, and the extraction rate of part of fat-soluble flavonoids is not high. Although the organic solvent extraction has good solubility of flavonoids, it usually needs to use high-concentration solvent, which has the problems of large solvent consumption, high recovery cost, safety hazard of flammable, environmental pollution and so on. At the same time, the conventional extraction method often has long extraction time and limited efficiency, and the extraction of ingredients from cell structure dense medicinal materials such as Spatholobi Caulis is not sufficient.

[0005] After obtaining the crude extract, further enrichment and purification of flavonoids is the key step to improve the value of the product. Common methods include solvent extraction, precipitation, column chromatography and so on. Solvent extraction needs to use a large amount of flammable organic solvent, the operation steps are complicated, and it is easy to cause emulsification and loss of effective components. The selectivity of precipitation method is limited, and part of the target components may be precipitated at the same time, resulting in low recovery rate. Although macroporous adsorption resin method shows certain advantages in flavonoid enrichment, in actual application, if the crude extract contains a large amount of macromolecular impurities such as polysaccharide, tannin and protein, the resin is easily contaminated, the adsorption capacity and regeneration efficiency are reduced, thereby affecting the purification effect and service life of the resin. The existing technology usually optimizes extraction and purification as two independent links, and lacks integrated and collaborative process design from raw material pretreatment to final product.

[0006] In summary, the existing Spatholobi Caulis processing technology has several outstanding shortcomings: first, the efficiency and quality of the drying link are difficult to balance, which easily causes the loss of heat-sensitive flavonoid components; second, the solvent used in the extraction link is not environmentally friendly, the selectivity is poor, and the efficiency needs to be improved; third, the pretreatment in the purification link is insufficient, the resin is easily contaminated, and the contradiction between enrichment efficiency and cost control is prominent; fourth, the links are relatively isolated, and a systematic and efficient processing chain has not been formed. Therefore, it is urgent to develop an innovative integrated processing technology which integrates efficient drying, green extraction and targeted enrichment, so as to improve the processing quality, production efficiency and product competitiveness of Spatholobi Caulis as a whole.

[0007] The disclosure of the above background art content is only used to assist in understanding the inventive concept and technical solutions of the present application, and it does not necessarily belong to the prior art of the present patent application. In the absence of explicit evidence that the above content has been disclosed before the filing date of the present patent application, the above background art should not be used to evaluate the novelty and inventiveness of the present application. SUMMARY

[0008] The main objective of this invention is to propose a processing technology for *Spatholobus suberectus* that integrates efficient drying, green extraction, and targeted enrichment, in order to solve the technical problems of low processing efficiency, easy destruction of active ingredients, environmentally unfriendly extraction and purification processes, and difficulty in obtaining high-purity flavonoid products in the existing technologies.

[0009] To achieve the above technical objectives, the present invention adopts the following technical solution:

[0010] An integrated processing technology for efficient drying and flavonoid enrichment of *Spatholobus suberectus* includes the following sequential steps:

[0011] S1. Raw material pretreatment: Cut fresh chicken blood vine stems into oblique slices with a thickness of 4-6mm and perform vacuum low temperature pulse explosion pretreatment.

[0012] S2. Segmented Coupled Drying: The pretreated chicken blood vine slices are first rapidly dehydrated by microwave, and then slowly dried by low temperature hot air to obtain dried chicken blood vine slices.

[0013] S3. Extraction of flavonoids: The dried chicken blood vine slices were crushed and extracted with an aqueous eutectic solvent as the extractant, combined with ultrasonic assistance, to obtain a crude extract.

[0014] S4. Enrichment of flavonoids: After membrane filtration, the crude extract was loaded onto a macroporous adsorption resin chromatography column and eluted with an ethanol-water gradient. The target eluted fraction was collected, concentrated under reduced pressure, and dried under vacuum to obtain the chicken blood vine flavonoid extract.

[0015] Preferably, in step S1, the process parameters for the vacuum cryogenic pulse explosion pretreatment are as follows: first, the material is placed in a vacuum chamber and evacuated to an absolute pressure of 0.08-0.10 MPa; then, saturated water vapor is introduced to raise the gauge pressure inside the chamber to 0.05-0.15 MPa within 10-30 seconds and maintain it for 10-30 seconds; finally, the pressure is released instantaneously and the vacuum is restored. The above operation is repeated 1-3 times.

[0016] Preferably, in step S2, the microwave power density used for rapid microwave dehydration is 5-10 W / g, and the moisture content of the material at the end of dehydration is 30-40%; the temperature of the low-temperature hot air slow drying is 40-55℃, the wind speed is 0.5-1.5 m / s, and the moisture content of the material at the end of drying is less than 10%.

[0017] Preferably, after step S2, an infrared radiation shaping process is added: the material is placed in an infrared radiation field with a wavelength of 2.5-4.0μm, the material temperature is controlled to be maintained in the range of 45-55℃, and the process is continued for 3-8 minutes.

[0018] Preferably, the aqueous eutectic solvent in step S3 is prepared by mixing the hydrogen bond donor lactic acid and the hydrogen bond acceptor choline chloride in a molar ratio of 2:1-3:1 and adding deionized water, wherein the mass fraction of water is 20-30%.

[0019] Preferably, the pH value of the aqueous eutectic solvent is 5.0-6.0.

[0020] Preferably, the extraction process parameters in step S3 are as follows: the material-to-liquid ratio is 1:15-1:25, the ultrasonic power is 200-400W, the extraction temperature is 50-60℃, and the extraction time is 20-40min.

[0021] Preferably, in step S4, the membrane filtration separation operation is microfiltration and ultrafiltration in sequence, wherein the pore size of the microfiltration membrane is 0.1-0.45 μm and the molecular weight cutoff of the ultrafiltration membrane is 5-10 kDa.

[0022] Preferably, in step S4, the macroporous adsorption resin used is AB-8, HPD-100, or D-101; the gradient elution operation sequentially uses distilled water, 20-30% ethanol-water solution, and 50-80% ethanol-water solution for stepwise elution.

[0023] The total flavonoids in the chicken blood vine flavonoid extract prepared by this invention are not less than 50% by weight of rutin, and the total weight of catechins and epicatechins accounts for more than 40% of the total flavonoids.

[0024] The beneficial effects of this invention compared to the prior art include:

[0025] 1. Advantages of systematic collaborative innovation

[0026] This invention achieves a highly efficient and synergistic systemic innovation in the processing pathway. Existing technologies typically treat the drying, extraction, and purification of medicinal materials as independent processes, optimizing them separately, lacking effective connection and synergy between the steps. This invention innovatively constructs a complete and continuous process chain from raw material pretreatment to the final high-purity extract. The steps are not simply sequentially linked, but rather deeply designed based on the idea that each step creates favorable conditions for the next. For example, pretreatment opens the way for drying and extraction, efficient drying ensures the uniformity of the extracted raw material quality, and the crude extract obtained through green extraction lays the foundation for subsequent efficient enrichment. This integrated design approach overcomes the efficiency losses and quality fluctuations caused by traditional segmented processing, achieving a simultaneous improvement in overall processing efficiency and product quality.

[0027] 2. Advantages of a gentle yet highly effective combination

[0028] A gentler and more efficient combination of technologies was employed in key processing stages. Addressing the tough texture and thermally unstable flavonoid components of *Spatholobus suberectus*, this invention avoids extreme treatment methods involving single high temperatures, prolonged durations, or high energy consumption. In the drying stage, rapid microwave heating is combined with gentle dehydration using low-temperature hot air, significantly shortening drying time while effectively protecting heat-sensitive components by controlling the upper temperature limit. In the pretreatment stage, vacuum low-temperature pulse burst technology is used to achieve a gentle loosening of the material structure through physical pressure difference changes, avoiding the loss or hydrolysis of active ingredients that could result from high-temperature cooking or prolonged soaking. The application of these combined technologies demonstrates the effective protection of the inherent quality and active ingredients of the medicinal material while pursuing processing efficiency.

[0029] 3. Advantages of green and precise purification

[0030] The extraction and purification processes adhered to the principles of green and precise methods. In the extraction stage, an aqueous eutectic solvent was used instead of traditional high-concentration organic solvents. This solvent system, composed of natural derivatives, is biodegradable, low in toxicity, and highly designable, reducing potential risks to the environment and operators, aligning with the development direction of green chemistry. In the purification stage, membrane separation technology was creatively combined with macroporous resin adsorption technology. First, membrane filtration rapidly removed large molecular impurities such as polysaccharides and proteins, reducing the contamination load on the resin column. Then, precise separation was achieved through the resin's specific adsorption and gradient elution of flavonoids. This combined strategy not only improved the overall efficiency of enrichment and purification but also extended the resin's lifespan and reduced purification costs.

[0031] 4. Stable and controllable process advantages

[0032] The overall process exhibits good stability and promising prospects for industrial application. The various unit technologies involved in this invention, such as vacuum processing, microwave drying, ultrasonic extraction, membrane separation, and resin column chromatography, are all mature and easily scalable unit operations in modern industry. Through precise definition and optimized combination of key process parameters in each step, the entire processing flow has clear operational guidelines and good repeatability. The process design balances technological advancement and engineering feasibility, providing a clear and reliable technical route for the transition from laboratory-scale to large-scale, continuous production while ensuring high product quality. This contributes to promoting the standardization and industrialization of high-value-added products from *Spatholobus suberectus* (chicken blood vine). Detailed Implementation

[0033] The present invention will be further described in detail below with reference to specific embodiments. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope and application of the present invention.

[0034] An integrated processing technology for efficient drying and flavonoid enrichment of *Spatholobus suberectus* includes the following sequential steps:

[0035] S1. Raw material pretreatment: Take 100g of fresh chicken blood vine stems, wash them, and cut them into oblique slices with a thickness of 4-6mm. Perform vacuum low temperature pulse explosion pretreatment. The process parameters are as follows: Place the slices in a vacuum chamber and evacuate to an absolute pressure of 0.08-0.10MPa. Then, introduce saturated water vapor to raise the gauge pressure in the chamber to 0.05-0.15MPa within 10-30s and maintain it for 10-30s. Finally, release the pressure instantaneously and restore the vacuum. This cycle is repeated 1-3 times.

[0036] S2. Segmented Coupled Drying: The pretreated chicken blood vine slices are rapidly dehydrated using microwaves at a power density of 5-10 W / g until the moisture content reaches 30-40%. Then, they are slowly dried using low-temperature hot air at 40-55℃ and a wind speed of 0.5-1.5 m / s until the moisture content is below 10%, yielding dried chicken blood vine. An optional infrared radiation shaping step can then be performed: the material is placed in an infrared radiation field with a wavelength of 2.5-4.0 μm, and the material temperature is controlled within the range of 45-55℃ for 3-8 minutes.

[0037] S3. Extraction of flavonoids: Pulverize dried chicken blood vine, take 20g of powder, and use an aqueous eutectic solvent as the extractant. The aqueous eutectic solvent is prepared by mixing hydrogen bond donor lactic acid and hydrogen bond acceptor choline chloride in a molar ratio of 2:1-3:1 and adding deionized water, wherein the mass fraction of water is 20-30%, and the pH value is adjusted to 5.0-6.0. The extraction conditions are: the material-to-liquid ratio of aqueous eutectic solvent is 1:15-1:25, the ultrasonic power is 200-400W, the extraction temperature is 50-60℃, and the extraction time is 20-40min. After extraction, filter to obtain crude extract.

[0038] S4. Enrichment of Flavonoids: The crude extract was filtered sequentially through microfiltration and ultrafiltration membranes to remove impurities. The microfiltration membrane had a pore size of 0.1-0.45 μm, and the ultrafiltration membrane had a molecular weight cutoff of 5-10 kDa. The filtrate was loaded onto an AB-8, HPD-100, or D-101 macroporous adsorption resin column and eluted with a gradient of ethanol-water solution, sequentially with distilled water, 20-30% (v / v) ethanol-water solution, and 50-80% (v / v) ethanol-water solution. The target eluent was collected. The collected eluent was concentrated under reduced pressure until no ethanol odor was detected, and then vacuum dried to constant weight to obtain the chicken blood vine flavonoid extract.

[0039] Technical principle of the invention:

[0040] First, in the raw material pretreatment stage, a vacuum low-temperature pulse blasting treatment with specific parameters is employed. This step, through the alternating action of vacuum and saturated steam, utilizes the instantaneous pressure difference between the material's internal and external environments under relatively mild temperature conditions to physically loosen and micro-invasively destroy the hard woody fiber structure and cell walls of the *Spatholobus suberectus*. This step is not independent; its primary function is to lay the foundation for all subsequent steps: it increases the porosity and specific surface area of ​​the material, thereby greatly reducing the resistance to moisture migration during subsequent drying, and also creating efficient channels for solvent penetration and component dissolution during the extraction stage. Without this step, the subsequent drying efficiency would be significantly reduced, and the extraction process would require extended time and more drastic conditions.

[0041] Secondly, in the drying stage, a specific combination and connection is employed between rapid microwave dehydration and slow low-temperature hot air drying. Microwave drying utilizes its volumetric heating characteristics to rapidly vaporize the moisture inside the material, quickly reducing a large amount of free water. Its high efficiency relies on the porous structure formed after pretreatment. However, if microwave drying is continued alone until the endpoint, it can easily lead to localized overheating and component damage. Therefore, this scheme switches to low-temperature hot air drying when the material's moisture content drops to a specific range. At this point, the loose structure formed by pretreatment also facilitates uniform hot air penetration, while the slow low-temperature process gently removes bound water, avoiding thermal stress damage, thus achieving a balance between high efficiency and quality preservation. The optional subsequent infrared radiation shaping, based on this drying process, uses radiation of a specific wavelength for a gentle final treatment, further stabilizing the material's microstructure.

[0042] Secondly, in the extraction stage, a specific composition and ratio of aqueous eutectic solvent is used, combined with ultrasound assistance. Pretreatment and drying together provide a loosely structured raw material with good stability of active ingredients, allowing extraction to proceed under gentler conditions. The complexation system formed by choline chloride and lactic acid in the aqueous eutectic solvent exhibits high selective solubility for flavonoids, while the addition of a specific proportion of water adjusts viscosity and permeability. Based on this physical structure, the ultrasonic cavitation effect further enhances solvent penetration into cells and the mass transfer rate of components. The synergistic effect of these three factors achieves selective and efficient extraction at lower temperatures and in shorter time periods, outperforming the use of traditional solvents or ultrasound treatment alone.

[0043] Finally, in the purification stage, a tandem process of membrane filtration and resin gradient elution is employed. The crude extract obtained is complex in composition, and direct loading would severely contaminate the resin. This scheme first uses a microfiltration and ultrafiltration membrane system to precisely remove macromolecular impurities such as proteins, polysaccharides, and tannins based on molecular size. This pre-purification step reduces the contamination load on the subsequent resin column, ensuring its adsorption capacity and regeneration performance. The clarified liquid after membrane filtration then enters a specific type of macroporous resin column, where the resin utilizes its surface adsorption characteristics to selectively adsorb components of different polarities. Subsequent ethanol-water gradient elution then performs precise sequential desorption and separation based on the difference in polarity between flavonoids and impurities. The functions of membrane separation and resin purification are clearly defined, and the order is irreversible. The former provides the necessary conditions for the efficient and stable operation of the latter, while the latter, based on the former, achieves precise capture and enrichment of target components, synergistically achieving high purity and high recovery rate.

[0044] In summary, the raw materials and processes of this invention are not isolated. Pretreatment creates the physical conditions for drying and extraction; efficient and gentle drying ensures the quality of the extracted raw materials; green and efficient extraction provides a suitable material basis for subsequent fine purification; and pre-membrane filtration directly ensures the performance of the core enrichment unit (resin column). The entire process chain constitutes an organic whole, with each link interconnected and complementary, jointly resolving the contradictions between drying efficiency and component activity protection, extraction efficiency and solvent greening, and purification effect and cost control in existing technologies, thus producing a synergistic effect.

[0045] To make the present invention more fully disclosed, more specific embodiments are described below.

[0046] Example 1:

[0047] An integrated processing technology for efficient drying and flavonoid enrichment of *Spatholobus suberectus* includes the following sequential steps:

[0048] S1. Raw material pretreatment: Take 100g of fresh chicken blood vine stem segments, wash them, and cut them into oblique slices with a thickness of 4mm. Perform vacuum low temperature pulse explosion pretreatment. The process parameters are as follows: place the slices in a vacuum chamber and evacuate to an absolute pressure of 0.08MPa. Then, introduce saturated water vapor to raise the gauge pressure in the chamber to 0.05MPa within 30s and maintain it for 30s. Finally, release the pressure instantly and restore the vacuum. Repeat the above operation 3 times.

[0049] S2. Segmented Coupled Drying: The pretreated chicken blood vine slices are rapidly dehydrated by microwave at a power density of 5W / g until the moisture content of the material is 40%; then, they are slowly dried by low-temperature hot air at a temperature of 40℃ and a wind speed of 0.5m / s until the moisture content of the material is 8%, thus obtaining dried chicken blood vine.

[0050] S3. Extraction of flavonoids: The dried chicken blood vine was pulverized and passed through a 40-mesh sieve. 20g of powder was taken and an aqueous eutectic solvent was used as the extractant. The aqueous eutectic solvent was prepared by mixing lactic acid and choline chloride in a molar ratio of 2:1 and adding deionized water. The water mass fraction was 30%, and the pH was adjusted to 5.0. The extraction conditions were: material-to-liquid ratio of 1:15 (g / mL), ultrasonic power of 200W, extraction temperature of 50℃, and extraction time of 40min. After extraction, the mixture was filtered to obtain the crude extract.

[0051] S4. Enrichment of flavonoids: The crude extract was filtered sequentially through a 0.1 μm microfiltration membrane and a 5 kDa ultrafiltration membrane to remove impurities. The filtrate was loaded onto an AB-8 macroporous adsorption resin chromatography column (column diameter 1.5 cm, column height 20 cm). Gradient elution was performed using ethanol-water solution, successively eluting with 3 column volumes of distilled water, 2 column volumes of 20% ethanol-water solution, and 3 column volumes of 50% ethanol-water solution. The 50% ethanol-water solution eluent was collected. The collected fraction was concentrated under reduced pressure at 55 °C until no ethanol odor remained, and then vacuum dried at 45 °C to constant weight to obtain 2.1 g of chicken blood vine flavonoid extract.

[0052] Example 2:

[0053] An integrated processing technology for efficient drying and flavonoid enrichment of *Spatholobus suberectus* includes the following sequential steps:

[0054] S1. Raw material pretreatment: Take 100g of fresh chicken blood vine stem segments, wash them, and cut them into oblique slices with a thickness of 4mm. Perform vacuum low temperature pulse explosion pretreatment. The process parameters are as follows: place the slices in a vacuum chamber and evacuate to an absolute pressure of 0.09MPa. Then, introduce saturated water vapor to raise the gauge pressure in the chamber to 0.10MPa within 20s and maintain it for 20s. Finally, depressurize instantaneously and restore vacuum. This cycle is repeated twice.

[0055] S2. Segmented Coupled Drying: The pretreated chicken blood vine slices are rapidly dehydrated by microwave at a power density of 8W / g until the moisture content of the material is controlled at 35%. Then, they are slowly dried by low-temperature hot air at a temperature of 50℃ and a wind speed of 1.0m / s until the moisture content of the material is 9%, thus obtaining dried chicken blood vine. After that, an infrared radiation shaping step is performed: the material is placed in an infrared radiation field with a wavelength of 3.0μm, and the material temperature is controlled within the range of 50℃ for 5 minutes.

[0056] S3. Extraction of flavonoids: The dried chicken blood vine was pulverized and passed through a 40-mesh sieve. 20g of powder was taken and an aqueous eutectic solvent was used as the extractant. The aqueous eutectic solvent was prepared by mixing lactic acid and choline chloride in a molar ratio of 2.5:1 and adding deionized water. The water mass fraction was 25%, and the pH was adjusted to 5.5. The extraction conditions were: material-to-liquid ratio 1:20 (g / mL), ultrasonic power 300W, extraction temperature 55℃, and extraction time 30min. After extraction, the mixture was filtered to obtain the crude extract.

[0057] S4. Enrichment of flavonoids: The crude extract was filtered sequentially through a 0.22 μm microfiltration membrane and an 8 kDa ultrafiltration membrane to remove impurities. The filtrate was loaded onto an HPD-100 macroporous adsorption resin column (column diameter 1.5 cm, column height 20 cm), and gradient elution was performed using ethanol-water solution. The elution was carried out sequentially with 4 column volumes of distilled water, 3 column volumes of 25% ethanol-water solution, and 4 column volumes of 65% ethanol-water solution. The 65% ethanol-water solution eluent was collected. The collected fraction was concentrated under reduced pressure at 58 °C until no ethanol odor was detected, and then dried under vacuum at 50 °C to constant weight to obtain 2.4 g of chicken blood vine flavonoid extract.

[0058] Example 3:

[0059] An integrated processing technology for efficient drying and flavonoid enrichment of *Spatholobus suberectus* includes the following sequential steps:

[0060] S1. Raw material pretreatment: Take 100g of fresh chicken blood vine stem segments, wash them, and cut them into oblique slices with a thickness of 5mm. Perform vacuum low temperature pulse explosion pretreatment. The process parameters are as follows: Place the slices in a vacuum chamber and evacuate to an absolute pressure of 0.09MPa. Then, introduce saturated water vapor to raise the gauge pressure in the chamber to 0.12MPa within 15s and maintain it for 15s. Finally, depressurize instantaneously and restore vacuum. This cycle is repeated twice.

[0061] S2. Segmented Coupled Drying: The pretreated chicken blood vine slices are rapidly dehydrated by microwave at a power density of 9W / g until the moisture content of the material is 32%. Then, they are slowly dried by low-temperature hot air at a temperature of 52℃ and a wind speed of 1.2m / s until the moisture content of the material is 7%, thus obtaining dried chicken blood vine. After that, an infrared radiation shaping step is performed: the material is placed in an infrared radiation field with a wavelength of 3.5μm, and the material temperature is controlled within the range of 53℃ for 4 minutes.

[0062] S3. Extraction of flavonoids: The dried chicken blood vine was pulverized and passed through a 40-mesh sieve. 20g of powder was taken and an aqueous eutectic solvent was used as the extractant. The aqueous eutectic solvent was prepared by mixing lactic acid and choline chloride in a molar ratio of 3:1 and adding deionized water. The water mass fraction was 22%, and the pH was adjusted to 5.8. The extraction conditions were: material-to-liquid ratio 1:22 (g / mL), ultrasonic power 350W, extraction temperature 58℃, and extraction time 25min. After extraction, the mixture was filtered to obtain the crude extract.

[0063] S4. Enrichment of flavonoids: The crude extract was filtered sequentially through a 0.3 μm microfiltration membrane and a 9 kDa ultrafiltration membrane to remove impurities. The filtrate was loaded onto an AB-8 macroporous adsorption resin column (column diameter 1.5 cm, column height 20 cm), and gradient elution was performed using ethanol-water solution. The elution was carried out sequentially with 4 column volumes of distilled water, 3 column volumes of 28% ethanol-water solution, and 4 column volumes of 70% ethanol-water solution. The 70% ethanol-water solution eluent was collected. The collected fraction was concentrated under reduced pressure at 56 °C until no ethanol odor was detected, and then vacuum dried at 52 °C to constant weight to obtain 2.8 g of chicken blood vine flavonoid extract.

[0064] Example 4:

[0065] An integrated processing technology for efficient drying and flavonoid enrichment of *Spatholobus suberectus* includes the following sequential steps:

[0066] S1. Raw material pretreatment: Take 100g of fresh chicken blood vine stem segments, wash them, and cut them into oblique slices with a thickness of 6mm. Perform vacuum low temperature pulse explosion pretreatment. The process parameters are as follows: Place the slices in a vacuum chamber and evacuate to an absolute pressure of 0.10MPa. Then, introduce saturated water vapor to raise the gauge pressure in the chamber to 0.15MPa within 10s and maintain it for 10s. Finally, release the pressure instantaneously and restore the vacuum. This cycle is repeated once.

[0067] S2. Segmented Coupled Drying: The pretreated chicken blood vine slices are rapidly dehydrated by microwave at a power density of 10W / g until the moisture content of the material is 30%. Then, they are slowly dried by low-temperature hot air at a temperature of 55℃ and a wind speed of 1.5m / s until the moisture content of the material is 6%, thus obtaining dried chicken blood vine. After that, an infrared radiation shaping step is performed: the material is placed in an infrared radiation field with a wavelength of 4.0μm, and the material temperature is controlled within the range of 55℃ for 3 minutes.

[0068] S3. Extraction of flavonoids: The dried chicken blood vine was pulverized and passed through a 40-mesh sieve. 20g of powder was taken and an aqueous eutectic solvent was used as the extractant. The aqueous eutectic solvent was prepared by mixing lactic acid and choline chloride in a molar ratio of 2.8:1 and adding deionized water. The water mass fraction was 28%, and the pH was adjusted to 6.0. The extraction conditions were: material-to-liquid ratio 1:25 (g / mL), ultrasonic power 400W, extraction temperature 60℃, and extraction time 20min. After extraction, the mixture was filtered to obtain the crude extract.

[0069] S4. Enrichment of flavonoids: The crude extract was filtered sequentially through a 0.45 μm microfiltration membrane and a 10 kDa ultrafiltration membrane to remove impurities. The filtrate was loaded onto a D-101 macroporous adsorption resin column (column diameter 1.5 cm, column height 20 cm), and gradient elution was performed using ethanol-water solution. The elution was carried out sequentially with 5 column volumes of distilled water, 4 column volumes of 30% ethanol-water solution, and 5 column volumes of 80% ethanol-water solution. The 80% ethanol-water solution eluent was collected. The collected fraction was concentrated under reduced pressure at 60 °C until no ethanol odor was detected, and then dried under vacuum at 55 °C to constant weight to obtain 2.5 g of chicken blood vine flavonoid extract.

[0070] Example 5:

[0071] An integrated processing technology for efficient drying and flavonoid enrichment of *Spatholobus suberectus* includes the following sequential steps:

[0072] S1. Raw material pretreatment: Take 100g of fresh chicken blood vine stem segments, wash them, and cut them into oblique slices with a thickness of 4mm. Perform vacuum low temperature pulse explosion pretreatment. The process parameters are as follows: Place the slices in a vacuum chamber and evacuate to an absolute pressure of 0.085MPa. Then, introduce saturated water vapor to raise the gauge pressure in the chamber to 0.08MPa within 25s and maintain it for 25s. Finally, depressurize instantaneously and restore vacuum. This cycle is repeated twice.

[0073] S2. Segmented Coupled Drying: The pretreated chicken blood vine slices are rapidly dehydrated by microwave at a power density of 6W / g until the moisture content of the material is 38%. Then, they are slowly dried by low-temperature hot air at a temperature of 45℃ and a wind speed of 0.8m / s until the moisture content of the material is 9%, thus obtaining dried chicken blood vine. After that, an infrared radiation shaping step is performed: the material is placed in an infrared radiation field with a wavelength of 2.5μm, and the material temperature is controlled within the range of 45℃ for 8 minutes.

[0074] S3. Extraction of flavonoids: The dried chicken blood vine was pulverized and passed through a 40-mesh sieve. 20g of powder was taken and an aqueous eutectic solvent was used as the extractant. The aqueous eutectic solvent was prepared by mixing lactic acid and choline chloride in a molar ratio of 2.2:1 and adding deionized water. The water mass fraction was 23%, and the pH was adjusted to 5.2. The extraction conditions were: material-to-liquid ratio 1:18 (g / mL), ultrasonic power 250W, extraction temperature 52℃, and extraction time 35min. After extraction, the mixture was filtered to obtain the crude extract.

[0075] S4. Enrichment of flavonoids: The crude extract was filtered sequentially through a 0.15 μm microfiltration membrane and a 6 kDa ultrafiltration membrane to remove impurities. The filtrate was loaded onto an HPD-100 macroporous adsorption resin column (column diameter 1.5 cm, column height 20 cm), and gradient elution was performed using ethanol-water solution. The elution was carried out sequentially with 3.5 column volumes of distilled water, 2.5 column volumes of 22% ethanol-water solution, and 3.5 column volumes of 55% ethanol-water solution. The 55% ethanol-water solution eluent was collected. The collected fraction was concentrated under reduced pressure at 52 °C until no ethanol odor was detected, and then vacuum dried at 48 °C to constant weight to obtain 2.2 g of chicken blood vine flavonoid extract.

[0076] Comparative Example 1 (lacking S1 vacuum cryogenic pulse explosion pretreatment):

[0077] S1. Raw material pretreatment: Take 100g of fresh chicken blood vine stem segments, wash them and cut them into 5mm thick oblique slices for direct use (without vacuum low temperature pulse explosion pretreatment).

[0078] S2. Segmented coupling drying: Same as in Example 3, microwave power density 9W / g, dehydrate to 32% moisture content; hot air drying temperature 52℃, wind speed 1.2m / s, dry to 7% moisture content, and then shape by infrared radiation.

[0079] S3. Extraction of flavonoids: Same as in Example 3, with the same ratio of aqueous eutectic solvent, pH value and extraction conditions, to obtain crude extract.

[0080] S4. Flavonoid enrichment: Same as in Example 3, with membrane filtration, gradient elution and post-treatment conditions, to obtain 1.5g of chicken blood vine flavonoid extract.

[0081] Comparative Example 2 (S2 is a single drying method, not a segmented coupled drying):

[0082] S1. Raw material pretreatment: Same as in Example 3, with the same vacuum low-temperature pulse explosion pretreatment conditions.

[0083] S2. Single drying: The pretreated chicken blood vine slices are dried slowly with low temperature hot air at 52℃ and 1.2m / s until the moisture content is 7% (without microwave rapid dehydration step), and then shaped by infrared radiation.

[0084] S3. Extraction of flavonoids: Same as in Example 3, with the same extraction conditions, to obtain crude extract.

[0085] S4. Enrichment of flavonoids: Same as in Example 3, with the same enrichment conditions, 1.8g of chicken blood vine flavonoid extract was obtained.

[0086] Comparative Example 3 (S3 was extracted using conventional ethanol, a non-aqueous eutectic solvent):

[0087] S1. Raw material pretreatment: Same as in Example 3, with the same vacuum low-temperature pulse explosion pretreatment conditions.

[0088] S2. Segmented coupled drying: Same as in Example 3, with consistent drying and shaping conditions.

[0089] S3. Extraction of flavonoids: Take 20g of dried chicken blood vine powder, use 70% ethanol as the extractant, the material-to-liquid ratio is 1:22 (g / mL), the ultrasonic power is 350W, the extraction temperature is 58℃, the extraction time is 25min, and the crude extract is obtained by filtration.

[0090] S4. Enrichment of flavonoids: Same as in Example 3, with the same enrichment conditions, 1.6g of chicken blood vine flavonoid extract was obtained.

[0091] Comparative Example 4 (S4 membrane-free filtration step):

[0092] S1. Raw material pretreatment: Same as in Example 3, with the same vacuum low-temperature pulse explosion pretreatment conditions.

[0093] S2. Segmented coupled drying: Same as in Example 3, with consistent drying and shaping conditions.

[0094] S3. Extraction of flavonoids: Same as in Example 3, with the same extraction conditions, to obtain crude extract.

[0095] S4. Enrichment of flavonoids: The crude extract was directly loaded onto an AB-8 macroporous adsorption resin column, followed by gradient elution and post-treatment as in Example 3, to obtain 2.0 g of chicken blood vine flavonoid extract.

[0096] Comparative Example 5 (S4 non-gradient elution, elution with only a single concentration of ethanol):

[0097] S1. Raw material pretreatment: Same as in Example 3, with the same vacuum low-temperature pulse explosion pretreatment conditions.

[0098] S2. Segmented coupled drying: Same as in Example 3, with consistent drying and shaping conditions.

[0099] S3. Extraction of flavonoids: Same as in Example 3, with the same extraction conditions, to obtain crude extract.

[0100] S4. Enrichment of flavonoids: The crude extract was filtered through a membrane and loaded onto an AB-8 macroporous adsorption resin column. It was eluted with only 4 column volumes of 70% ethanol-water solution. The eluted fraction was collected and post-processed as in Example 3 to obtain 1.7g of chicken blood vine flavonoid extract.

[0101] Extraction index detection test:

[0102] 1. Detection Indicators and Methods

[0103] Three core extraction indicators were selected, and the specific detection methods are as follows:

[0104] Total flavonoid mass fraction: The absorbance was measured at a wavelength of 510 nm using ultraviolet-visible spectrophotometry with rutin as a reference standard, and the total flavonoid mass fraction was calculated.

[0105] Total mass fraction of catechins + epicatechins: High performance liquid chromatography (HPLC reference: General Chapter 0512, Part IV, 2025 Edition of the Pharmacopoeia of the People's Republic of China) was used. The chromatographic column was a C18 column (4.6 mm × 250 mm, 5 μm), the mobile phase was methanol-0.1% phosphoric acid aqueous solution (25:75, v / v), the detection wavelength was 280 nm, the flow rate was 1.0 mL / min, and the column temperature was 30 ℃. The total mass fraction of the two was determined.

[0106] Extraction rate: Extraction rate = (total flavonoid mass in extract / total flavonoid mass in raw material) × 100%, and the total flavonoid mass in raw material is determined by the same detection method.

[0107] 2. Test Results

[0108] The extraction index measurement results for each embodiment and comparative example are shown in the table below:

[0109]

[0110] 3. Data Comparison and Theoretical Analysis:

[0111] (1) Data comparison and analysis:

[0112] Comparison between examples: Example 3 had the highest total flavonoid mass fraction (56.5%) and extraction rate (14.0%) among the examples, and the ratio of catechin + epicatechin to total flavonoids (44.6%) was also higher than other examples; its vacuum low-temperature pulse burst absolute pressure was 0.09 MPa; Example 4 had a slightly lower total flavonoid mass fraction (53.6%) than Example 3 due to the higher drying and extraction temperatures, which caused thermal degradation of some flavonoid components; Example 1 had the lowest extraction rate (10.5%) among the examples due to the lower extraction temperature.

[0113] Comparison of Examples and Comparative Examples: The total flavonoid mass fraction of all examples was ≥50.2%, while the total flavonoid mass fraction of comparative examples 1-5 was ≤46.8%; the extraction rate of examples was 10.5%-14.0%, while the extraction rate of comparative examples was 7.5%-10.0%, and the average extraction rate of examples was 3.2% higher than that of comparative examples; the ratio of catechin + epicatechin to total flavonoids in examples was ≥40.4%, while that in comparative examples was ≤39.3%, indicating that examples were superior in enrichment of the target components.

[0114] (2) Theoretical Analysis

[0115] The role of vacuum low-temperature pulse blasting pretreatment: Comparative Example 1, lacking this step, had an extraction rate of only 7.5%, a decrease of 6.5% compared to Example 3, and a decrease of 14.0% in total flavonoid mass fraction. Theoretically, vacuum low-temperature pulse blasting can loosen the cell structure and rupture the cell walls of the *Spatholobus suberectus* stem tissue at low temperatures, effectively reducing the mass transfer resistance of flavonoid components during subsequent extraction and significantly improving dissolution efficiency. If this treatment step is omitted, the *Spatholobus suberectus* stem cell structure remains intact and dense, making it difficult for flavonoid components to be fully released from the cells, thus leading to a significant decrease in extraction efficiency.

[0116] Advantages of segmented coupled drying: Comparative Example 2 used single hot air drying, with an extraction rate of 9.0%, which was 5.0% lower than that of Example 3. Segmented coupled drying first uses microwave rapid dehydration to shorten the drying time in the high moisture content stage and reduce the early loss of flavonoids; then it uses low-temperature hot air slow drying to avoid thermal degradation of flavonoids caused by high temperature. In contrast, single hot air drying is time-consuming and easily causes coking of materials and loss of flavonoids, affecting the subsequent extraction effect.

[0117] Advantages of extraction using aqueous eutectic solvents: Comparative Example 3, using conventional 70% ethanol extraction, yielded a total flavonoid mass fraction of 40.2%, which is 16.3% lower than that of Example 3. The aqueous eutectic solvent, composed of lactic acid and choline chloride, can form stable complexes with flavonoids through hydrogen bonding, increasing the solubility of flavonoids. Furthermore, its polarity is adjustable, resulting in higher selectivity for target components compared to traditional ethanol solvents, thus leading to superior extraction efficiency and enrichment effects.

[0118] Enrichment effect of membrane filtration and gradient elution: Comparative Example 4, which omitted the membrane filtration step, had a total flavonoid mass fraction of 46.8%, which was 9.7% lower than that of Example 3; Comparative Example 5, which used a single concentration of ethanol for elution, had an extraction rate of 8.5%, which was 5.5% lower than that of Example 3. Membrane filtration can remove impurities such as solid particles and large molecular proteins from the crude extract, reducing the occupation of the adsorption capacity of the macroporous adsorption resin by impurities; gradient elution can first elute weakly polar impurities, and then specifically elute flavonoid components, improving the purity of the target components, while single concentration elution is difficult to achieve effective separation of impurities and target components, resulting in a decrease in purity and extraction rate.

[0119] The above description, in conjunction with specific embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the inventive concept, and all such substitutions or modifications should be considered within the scope of protection of the present invention.

[0120] Although the invention and its advantages have been described in detail, it should be understood that various changes, substitutions, and modifications can be made without departing from the spirit and scope of the invention. Furthermore, the scope of the invention is not limited to the specific embodiments of the processes, methods, and steps described in the specification. From the disclosure of this invention, those skilled in the art will readily utilize existing or future processes, methods, steps that substantially perform the same function or achieve the same results as the corresponding embodiments described herein. Therefore, the appended claims are intended to cover such processes, methods, steps.

Claims

1. An integrated processing technology for efficient drying and flavonoid enrichment of *Spatholobus suberectus*, characterized in that, Includes the following sequential steps: S1. Raw material pretreatment: Cut fresh chicken blood vine stems into oblique slices with a thickness of 4-6mm and perform vacuum low temperature pulse explosion pretreatment; S2. Segmented Coupled Drying: The pretreated chicken blood vine slices are first rapidly dehydrated by microwave, and then slowly dried by low temperature hot air to obtain dried chicken blood vine. S3. Extraction of flavonoids: The dried chicken blood vine was crushed and extracted with an aqueous eutectic solvent and ultrasound-assisted extraction to obtain a crude extract. S4. Enrichment of flavonoids: After membrane separation and filtration, the crude extract is loaded onto a macroporous adsorption resin chromatography column and eluted with an ethanol-water gradient. The target eluted fraction is collected, concentrated under reduced pressure, and dried under vacuum to obtain the chicken blood vine flavonoid extract.

2. The integrated processing technology for efficient drying and flavonoid enrichment of *Spatholobus suberectus* according to claim 1, characterized in that, In step S1, the process parameters for vacuum cryogenic pulse explosion pretreatment are as follows: First, the material is placed in a vacuum chamber and evacuated to an absolute pressure of 0.08-0.10 MPa; then, saturated water vapor is introduced to raise the gauge pressure inside the chamber to 0.05-0.15 MPa within 10-30 seconds and maintain it for 10-30 seconds; finally, the pressure is released instantaneously and the vacuum is restored. The above operation is repeated 1-3 times.

3. The integrated processing technology for efficient drying and flavonoid enrichment of *Spatholobus suberectus* according to claim 1, characterized in that, In step S2, during the rapid microwave dehydration stage, the microwave power density is 5-10 W / g, and the moisture content of the material at the end of dehydration is controlled to be 30-40%. In the low-temperature hot air slow drying stage, the temperature is set to 40-55℃, the wind speed is 0.5-1.5 m / s, and the moisture content of the material at the end of drying is reduced to below 10%.

4. The integrated processing technology for efficient drying and flavonoid enrichment of *Spatholobus suberectus* according to claim 3, characterized in that, After step S2, an infrared radiation shaping process is added: the material is placed in an infrared radiation field with a wavelength of 2.5-4.0μm, the material temperature is controlled to be maintained in the range of 45-55℃, and the process is continued for 3-8 minutes.

5. The integrated processing technology for efficient drying and flavonoid enrichment of *Spatholobus suberectus* according to claim 1, characterized in that, The aqueous eutectic solvent used in step S3 is prepared by mixing the hydrogen bond donor lactic acid and the hydrogen bond acceptor choline chloride in a molar ratio of 2:1-3:1, and then adding deionized water, wherein the mass fraction of water is 20-30%.

6. The integrated processing technology for efficient drying and flavonoid enrichment of *Spatholobus suberectus* according to claim 5, characterized in that, The pH value of the aqueous eutectic solvent is 5.0-6.

0.

7. The integrated processing technology for efficient drying and flavonoid enrichment of *Spatholobus suberectus* according to claim 1, 5, or 6, characterized in that, The extraction process parameters in step S3 are as follows: the material-to-liquid ratio is 1:15-1:25, the ultrasonic power is 200-400W, the extraction temperature is controlled at 50-60℃, and the extraction time is 20-40min.

8. The integrated processing technology for efficient drying and flavonoid enrichment of *Spatholobus suberectus* according to claim 1, characterized in that, The membrane filtration separation operation used in step S4 involves two stages of treatment: microfiltration and ultrafiltration. The microfiltration membrane has a pore size of 0.1-0.45 μm, and the ultrafiltration membrane has a molecular weight cutoff of 5-10 kDa.

9. The integrated processing technology for efficient drying and flavonoid enrichment of *Spatholobus suberectus* according to claim 1, characterized in that, The macroporous adsorption resin used in step S4 is AB-8, HPD-100, or D-101; the gradient elution operation sequentially uses distilled water, 20-30% ethanol-water solution, and 50-80% ethanol-water solution for stepwise elution.

10. A flavonoid extract of *Spatholobus suberectus*, prepared by the process described in any one of claims 1-9, characterized in that, The total flavonoids in the extract, calculated as rutin, shall not be less than 50%, and the total mass of catechins and epicatechins shall account for more than 40% of the total flavonoids.

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