Ginseng can have a wide range of pesticides used on it, with various types in circulation. How to process Pesticide-Free Ginseng Extract Ginseng Polysaccharides & Saponins?
In the early stages, pesticide residues in ginseng primarily included traditional pesticides such as organochlorines, organophosphates, and pyrethroids. However, with the emergence of pesticide resistance and the imposition of pesticide use policies, the types of pesticides used have gradually changed. New pesticides such as amides, dicarboximides, and triazoles have been introduced for the control of ginseng diseases. The use of these new pesticides improves the ability to manage pests and diseases; for example, prochloraz, mepanipyrim, and carbendazim can effectively control ginseng black spot disease, but this has led to a problem of excessive pesticide residue types in ginseng.
| Pesticide Registration for Major Ginseng Diseases | |
| Black Spot Disease: | There are 30 registered pesticide products for the control of black spot disease, including 29 single agents and 1 mixed agent. These products involve 14 active pesticide ingredients, including 3 triazoles, 2 methoxyacrylate esters, 2 inorganic copper compounds, 1 each of dicarboximide, phenylpyrimidine, inorganic sulfur, carboxamide, and antibiotics, as well as 1 biological pesticide-related active ingredient. Among these, the pesticide with the most registrations is wuxazolol (a triazole), with 10 products registered. This is followed by polyoxin with 4 registered products, and pyraclostrobin with 3 registered products. |
| Downy Mildew: | There are 14 registered pesticide products for downy mildew, including 5 single agents and 9 mixed agents. These products involve 18 active ingredients, including 3 phenylamide and urea compounds, 3 carboxamide compounds, 2 methoxyacrylate esters, and 1 each of phenylamide, carbamate, carboxamide, phenylpyrimidine, fluorobenzamide, carboxylic acid-benzamide, neonicotinoids, pyrazole, inorganic sulfur, and oxazole compounds, as well as 1 biological pesticide-related active ingredient. Among these, the most commonly used active ingredient is metalaxyl (a phenylamide), with 3 registered products. Other notable active ingredients include mefenoxam hydrochloride, mancozeb, and pyraclostrobin, each with 2 registered products. |
| Damping-Off Disease: | There are 9 registered pesticide products for damping-off disease, including 6 single agents and 3 mixed agents. These products involve 9 active ingredients. There are 4 biological pesticide-related products. The active ingredients with the most registered products are fludioxonil and metalaxyl, each with 3 products registered. Other ingredients include sodium dichloroisocyanurate, fluopicolide, carbendazim, and thiamethoxam, each with 1 registered product. |
| Gray Mold, Root Rot, Damping-Off, Rust, and Anthracnose Diseases: | The number of pesticide products registered for gray mold, root rot, damping-off, rust, and anthracnose diseases is relatively small, with the following numbers of registered products:
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Processing
The history of ginseng processing dates back to the Han Dynasty, and many processing methods have been developed. In modern times, the main ginseng processing methods include sun-dried ginseng, red ginseng, and highly concentrated ginseng.
However, studies have found that there is no significant change in pesticide residue levels before and after processing. The different processing methods have little effect on the pesticide residue in ginseng and cannot effectively reduce pesticide residues.
As a result, pesticide-free ginseng products are difficult to produce with traditional processing methods.
Pesticide-Free Ginseng Products
Pesticide-Free Ginseng Powder Washing fresh ginseng only removes surface pesticide residues and those carried by the soil. Mechanical washing is also inefficient in removing pesticide residues that have strongly adhered to the fibers of the ginseng. Therefore, processing pesticide-free ginseng powder is very difficult, and it’s challenging to obtain an ideal product.
Ginseng Polysaccharides Ginseng polysaccharides are relatively easier to obtain without pesticide residues. The extraction process of polysaccharides includes a procedure where solvents are used to first separate saponins. Since saponins themselves act as surfactants, they enhance the extraction ability of the solvent. By completely extracting saponins, the pesticide residues are entirely transferred into the solvent, resulting in pesticide-free ginseng polysaccharides.
Moreover, the refining process for ginseng polysaccharides involves solvent washing and crystallization, which further separates the polysaccharides from pesticide residues.
Ginseng Saponins Ginseng saponins are a type of surfactant that exhibits solubilizing and emulsifying properties. As a result, it is very difficult to treat any impurities in ginseng saponins, and this process requires a significant amount of effort.
When extracting ginseng, a frustrating issue arises: pesticides that originally didn’t interact with the saponins may dissolve and fully mix with the saponins. What’s even more troubling is that because of the properties of the saponins, pesticides and lipids with similar polarity are transferred from the ginseng into the solvent-saponin mixture, creating a very stable system both thermodynamically and kinetically.
This means that any method to completely remove pesticide residues needs to address the complete transformation of this system in both kinetic and thermodynamic terms. In other words, the process involves significant input and changes, resulting in two entirely different systems before and after the treatment, and whether we can still consider them as slightly different forms of the same substance is a matter for serious discussion.
Methods to separate saponins from pesticide residues generally involve solid-liquid separation using adsorbents or liquid-liquid separation with two immiscible liquids. The significant difference in solubility of pesticides and saponins in the two solvents creates the chemical potential for separation. However, due to the unique properties of saponins, it is nearly impossible to find an adsorbent or solvent that achieves ideal separation.
Therefore, accepting the significant loss of saponins, for example, 60%, is a wise choice. In fact, this is often the smart approach because such a loss level suggests the adsorbent or solvent selection is reasonable.
The advantage of a rationally low yield in industrial settings is clear. Having a clear and effective endpoint judgment method is often more suitable for quality management than investing millions in equipment and employing experienced testing personnel. A reproducible low yield with acceptable precision is much more industrially viable than high-cost, high-difficulty testing with poor reproducibility and lower timeliness, making it much more appealing to experienced workshop managers.
Saponins tend to increase the viscosity of solution systems, which is an undesirable property for production. High viscosity complicates adsorption and the complete phase separation required for extraction, making it a significant challenge.
Therefore, the formulation of methods to treat pesticide residues in ginseng is not fundamentally about choosing resins or solvents, but about selecting the right saponins. Understanding saponins and surfactants is perhaps the key issue.
