CN-121974962-A - Jin Xiutian tea glycoside syrup extraction and purification method based on membrane separation technology

Abstract

The invention relates to a Jin Xiutian tea glycoside syrup extraction and purification method based on a membrane separation technology, and belongs to the technical field of natural product extraction and purification. The method takes Jin Xiutian tea leaves as raw materials, sequentially carries out drying and crushing, continuous countercurrent extraction and centrifugal pretreatment, adopts a multistage membrane system consisting of a ceramic ultrafiltration membrane and a nanofiltration membrane for separation and purification, and then carries out three-stage gradient concentration and sterile filling to prepare the rubusoside syrup. The ceramic membrane is used for debitterizing and decoloring, entrapping colloid and macromolecular impurities, and the nanofiltration membrane is used for realizing the accurate separation of rubusoside and micromolecular impurities based on molecular sieving. The method does not need to use chemical flocculating agent and resin regenerant, the process is continuous and stable, the rubusoside yield is not less than 86%, the purity is not less than 89%, the recycling rate of concentrated water is not less than 92%, the energy consumption is reduced by more than 50% compared with the traditional process, the COD emission is reduced by more than 60%, and the method is suitable for large-scale green production.

Inventors

• HUANG YUYUAN
• WEI YULIN

Assignees

• 黑马当先(金秀)绿色农业科技有限公司

Dates

Publication Date

20260505

Application Date

20260127

Claims (10)

1. 1. A Jin Xiutian tea glycoside syrup extraction and purification method based on a membrane separation technology is characterized by comprising the following steps: S1, raw material pretreatment, namely selecting Jin Xiutian sweet tea leaves of tea as raw materials, drying and crushing to obtain sweet tea powder; S2, continuous countercurrent extraction, namely feeding the sweet tea powder obtained in the step 1 into a continuous countercurrent extraction unit through a quantitative conveying feeder, and adding raw water for extraction to obtain sweet tea extract; s3, centrifugal pretreatment, namely performing centrifugal separation on the sweet tea extract obtained in the step S2, and collecting the centrifugal liquid; S4, membrane separation and purification, namely treating the centrifugate obtained in the step 3 by a ceramic membrane separation unit, collecting clear liquid, sending the clear liquid into a nanofiltration membrane system for separation, and collecting purified clear liquid, wherein the molecular weight cut-off of the nanofiltration membrane system is 150-300Da; S5, concentrating, namely carrying out gradient concentration on the purified clear liquid obtained in the step S4 to obtain a rubusoside concentrated solution; s6, preparing a finished product, namely aseptically filling the rubusoside concentrated solution obtained in the step 5 to obtain a Jin Xiutian finished product of the rubusoside syrup.
2. 2. The method according to claim 1, wherein in step S1, the temperature of the drying is 60-80 ℃, and the particle size of the crushed sweet tea powder is 40-80 mesh.
3. 3. The method according to claim 1, wherein in step S2, the solid-to-liquid ratio of the extraction is 1:12 and the extraction time is 1.5 hours.
4. 4. The method according to claim 1, wherein in step S3, the centrifugal separation is performed by a disk centrifuge with a separation factor of 3000-4500r/min and a centrifugation time of 10-20 minutes.
5. 5. The method according to claim 1, wherein in step S4, the membrane pore diameter of the ceramic membrane separation unit is 50-200nm, and the ceramic membrane is made of alumina or zirconia.
6. 6. The method according to claim 1 or 5, wherein in step S4, the nanofiltration membrane system is operated at a pressure of 1.0-3.0MPa and at a temperature of 25-40 ℃, and the nanofiltration membrane is made of polyamide.
7. 7. The method according to claim 1, wherein in the step S5, the gradient concentration comprises the steps of carrying out preliminary concentration through a membrane concentration unit with a molecular weight cut-off of 300-500Da, and then carrying out further concentration through a double-effect concentrator and a spherical scraped wall concentrator in sequence, wherein the operation temperature of the double-effect concentrator is 70-85 ℃, the vacuum degree is-0.06-0.08 MPa, and the stirring rotating speed of the spherical scraped wall concentrator is 30-50r/min.
8. 8. The method of claim 7, wherein in step S5, the concentration endpoint control syrup solids content is 60-70%.
9. 9. The method according to claim 1, wherein in step S5, the concentrated recovered water produced in the concentration process is reused as the extraction make-up water at a reuse rate of not less than 92%.
10. 10. A sweet tea glycoside syrup, characterized in that it is prepared by the method of any one of claims 1-9, wherein the purity of sweet tea glycoside is not less than 89% and the yield is not less than 86%.

Description

Jin Xiutian tea glycoside syrup extraction and purification method based on membrane separation technology Technical Field The invention belongs to the technical field of natural product extraction and purification, and particularly relates to a Jin Xiutian tea glycoside syrup extraction and purification method based on a membrane separation technology. Background Jin Xiutian tea (Lithocarpus litseifolius) is a special medicinal and edible plant resource in China, rubusoside (rubusoside) rich in leaves is a natural diterpenoid glycoside compound, has the characteristics of high sweetness (about 200-300 times of sucrose), low calorie, no participation in human metabolism and the like, has the physiological activities of clearing heat, moistening lung, assisting in regulating blood sugar and the like, and has wide application prospects in the fields of functional foods, health-care beverages, medical preparations, daily chemicals and the like. Currently, the mainstream technology of industrially extracting and purifying rubusoside from Jin Xiutian tea leaves still generally depends on ion exchange resin or macroporous adsorption resin chromatography technology. The traditional process generally comprises the steps of water or alcohol solution extraction, filtration, resin column adsorption, alcohol-water solution gradient elution, eluent collection, concentration and drying and the like. Although this technology is mature, several bottleneck problems are gradually exposed in practical scale production: The separation efficiency and the yield are low, the adsorption selectivity of the resin to the rubusoside is limited, the target component is easy to co-adsorb or competitively adsorb impurities with similar structures in the adsorption-desorption process, the desorption is incomplete, the rubusoside yield is generally low (often lower than 80%), and the product purity improvement space is limited. The production process is discontinuous, the operation cost is high, the resin column needs to be periodically subjected to adsorption saturation, washing, desorption and regeneration, the resin column belongs to an intermittent production mode, seamless continuous connection with the front and back working procedures is difficult to realize, and the overall production efficiency is limited. The frequent resin regeneration consumes a large amount of acid and alkali solution, which not only increases the cost of raw materials, but also increases the operation burden of acid-base storage and neutralization treatment. The environmental pollution pressure is high, a large amount of high-salt wastewater containing acid, alkali and organic matters is generated in the resin regeneration process, the Chemical Oxygen Demand (COD) and the salt content are high, the treatment difficulty is high, the cost is high, the environment is not friendly, and the requirements of increasingly strict clean production and environmental protection regulations are not met. There is a risk of product safety, namely, the resin itself may be degraded or a regenerant which remains incompletely eluted, and there is a risk of introducing chemical residues into the final product, which affects the edible safety of the product, and particularly restricts the application of the regenerant in the fields of high-end foods and medicines. The membrane separation technology is a molecular-grade separation technology based on physical mechanisms such as screening, diffusion, charge action and the like, and has the remarkable advantages of no phase change in the process, no need of adding chemical reagents, mild operation conditions, easiness in modularized design and amplification, capability of realizing continuous automatic operation and the like. In recent years, membrane integration processes with Ultrafiltration (UF) and Nanofiltration (NF) as cores are successfully applied in the fields of natural product extraction, fruit juice clarifying bacteria, polysaccharide purification and the like, and the potential of replacing or optimizing the traditional separation and purification process is shown. Therefore, a novel process for extracting and purifying rubusoside, which can overcome the defects of the traditional resin process and has the characteristics of high yield, high purity, continuity, low energy consumption and low pollution, is developed. Disclosure of Invention The invention provides a Jin Xiutian tea glycoside syrup extraction and purification method based on a membrane separation technology in order to solve the problems in the prior art. In order to solve the technical problems, the invention is realized by the following technical scheme that in the first aspect, the Jin Xiutian tea glycoside syrup extraction and purification method based on the membrane separation technology comprises the following steps: S1, raw material pretreatment, namely selecting Jin Xiutian sweet tea leaves of tea as raw materials, drying and crushing to obtain sw