CN-121974963-A - Method for extracting and purifying tannin from camellia oleifera shells

Abstract

The invention belongs to the technical field of purification methods of natural products, and particularly relates to a method for extracting and purifying tannins from camellia oleifera shells. The invention uses shell waste after oil tea oil extraction as raw material and ethanol solution as leaching agent to extract tannin. Compared with the traditional tannin extraction method using acetone, the tannin extraction method has the advantages of lower toxicity, lower cost, easy recovery, simple process, effective tannin extraction and contribution to popularization and application in industrial production practice.

Inventors

• LI GUOHUA
• YANG ZIJIE

Assignees

• 浙江工业大学

Dates

Publication Date

20260505

Application Date

20251224

Claims (9)

1. 1. A method for extracting and purifying tannins from camellia oleifera shells, which is characterized by comprising the following steps: (S.1) extracting, namely adding an ethanol aqueous solution into oil tea shells serving as a raw material for leaching to obtain a crude extract; (S.2) purifying, namely adsorbing the crude extract obtained in the step (S.1) through a macroporous adsorption resin column, eluting by adopting distilled water and ethanol water solution in sequence, and collecting eluent; And (S.3) drying, namely drying the eluent obtained in the step (S.2) to obtain the pure oil tea tannin product.
2. 2. The method for extracting and purifying tannin from camellia oleifera shells of claim 1, wherein the concentration of ethanol water solution in the step (s.1) is 20-80% by volume.
3. 3. The method for extracting and purifying tannins from camellia oleifera shells according to claim 1, wherein the extraction temperature of the leaching in the step (s.1) is 50-70 ℃ and the extraction time is 1.5-3 h.
4. 4. The method for extracting and purifying tannin from camellia oleifera shells of claim 1, wherein in the step (s.1), the solid-to-liquid ratio of the raw material to the ethanol aqueous solution is 1:12-20.
5. 5. The method for extracting and purifying tannins from camellia oleifera shells of claim 1, wherein the macroporous adsorption resin is ADS-17 macroporous resin.
6. 6. The method for extracting and purifying tannin from camellia oleifera shells of claim 1, wherein in the step (s.2), the flow rate of the crude extract to the macroporous adsorption resin is 1-3 BV/h, and the sample loading amount is 4-5 BV.
7. 7. The method for extracting and purifying tannin from camellia oleifera shells according to claim 1, wherein in the step (s.2), the volume concentration of the aqueous ethanol solution used for elution is 60-80%.
8. 8. The method for extracting and purifying tannins from camellia oleifera shells according to claim 1, wherein in the step (s.2), the eluting flow rate of eluting with distilled water is 2-4 BV/h, and the eluting flow rate of eluting with ethanol aqueous solution is 2-3 BV/h.
9. 9. The method of extracting and purifying tannins from camellia oleifera shells of claim 1, wherein in step (s.3), the drying is vacuum drying or spray drying.

Description

Method for extracting and purifying tannin from camellia oleifera shells Technical Field The invention belongs to the technical field of purification methods of natural products, and particularly relates to a method for extracting and purifying tannins from camellia oleifera shells. Background The oil tea is a perennial woody plant and is widely distributed in Yangtze river basin and south area of China. The tree species has drought resistance and barren resistance, and has wide applicable range and remarkable ecological and economic benefits. The method can develop the camellia oleifera planting greatly, not only can open up high-quality edible oil sources and increase income of forest farmers, but also plays an important role in greening barren mountains, maintaining water and soil, regulating climate and improving ecological environment in mountain areas. Before the tea fruit is squeezed, shells are required to be peeled off, and the shells are called camellia oleifera shells. Other non-lipid substances such as tea saponin, tannins, caffeine, etc. exist in the shell of oil tea fruit. Tea saponin and tannins have good biological activity, and still have good prospects in the field of biological research, but in the actual production process, oil tea shells are generally wasted. In addition to tea saponin, the camellia oleifera shell contains about 8% (on a dry basis) tannins. Tannins, also known as tannins, are a relatively complex class of structurally phenolic compounds that are widely found in plants and which can combine with proteins to form water-insoluble precipitates that combine with proteins in raw hides to form dense, flexible, corrosion-resistant and waterproof leather. In the oil tea industry nowadays, after oil tea presses oil, produced oil tea shells are generally abandoned, and resource waste is caused. Meanwhile, the oil tea resource industry is single, new products except tea oil are required to be produced to optimize industrial chains such as tannins, tea saponin, caffeine and the like, so that tea oil byproducts are increased, resource waste is reduced, and green and environment-friendly benefits are increased. Disclosure of Invention The invention aims to provide a method for extracting and purifying tannin from camellia oleifera shells, so that tea oil byproducts are increased, resource waste is avoided, and green and environment-friendly benefits are increased. In order to achieve the aim of the invention, the invention is realized by the following technical scheme: a method for extracting and purifying tannin from camellia oleifera shells comprises the following steps: (S.1) extracting, namely adding an ethanol aqueous solution into oil tea shells serving as a raw material for leaching to obtain a crude extract; (S.2) purifying, namely adsorbing the crude extract obtained in the step (S.1) through a macroporous adsorption resin column, eluting by adopting distilled water and ethanol water solution in sequence, and collecting eluent; And (S.3) drying, namely drying the eluent obtained in the step (S.2) to obtain the pure oil tea tannin product. The invention uses ethanol water solution as leaching agent, which fundamentally avoids the toxicity problem of traditional solvents such as acetone. Further through systematic research, the feasibility of using the ethanol water solution as the leaching agent is determined, and the concentration range is optimized, so that the tannin can be effectively dissolved out of the complex matrix of the camellia oleifera shell, and simultaneously, the co-extraction of other impurities is reduced, thereby laying a good foundation for subsequent purification. Besides tannin, crude oil tea shell extract also contains various impurities such as saccharides, pigments, tea saponin and the like, and the traditional purification method such as a precipitation method and the like often has complicated operation, low yield or easy introduction of new impurities. The invention innovatively designs a multi-stage elution flow, namely, distilled water is used for elution, and then ethanol water solution is used for elution. The distilled water is used for eluting, so that the polarity is utilized, the impurities with strong polarity (such as partial saccharides, inorganic salts and the like) adsorbed on the resin are washed off preferentially, and the tannins are reserved due to stronger affinity with the resin. Through preliminary separation, a large amount of water-soluble impurities are effectively removed, and the burden of the subsequent ethanol elution stage is lightened. Then eluting with ethanol water solution with proper concentration, and destroying interaction between tannin and resin by utilizing the characteristic of ethanol of reducing the polarity of the solution, thereby selectively desorbing target product tannin. The stepwise elution strategy sequentially using the eluents with different polarities enables tannins and impurities to be separated