Study On Transfer And Removal Of Pesticide Residues In Ginseng Processing

Traditional Chinese medicine(TCM)plays an important role in China’s medical treatment and health care.However,in recent years,the problem of excessive pesticide residues is becoming more and more serious.Chinese medicinal materials are usually extracted and processed into decoction or preparations before people take them.Some pesticide residues may be concentrated and accumulated during the extraction and processing process,thus bringing greater risks to the safety of Chinese medicinal materials and their products.Therefore,it is of great significance to clarify the transfer rule of pesticide residues in the process of TCM extraction and processing for the quality control of TCM.This study chose ginseng as root-stock representative of traditional Chinese medicine,selected commonly detected pesticide residues as the research object,monitored the change of pesticide residues and calculated the processing factors in ginseng commonly used process,clarified the transfer rule of pesticide residues in the process,and tried to take advantage of the supercritical carbon dioxide extraction method for removing pesticide residues in ginseng slices.The following are the main research results.1.Establishment of pesticide residue detection methods:Through literature investigation,30 pesticides commonly detected in root medicinal materials such as ginseng were selected.GC-MS/MS and HPLC-MS/MS qualitative and quantitative analysis methods for 30 pesticides commonly detected in complex substrates,such as raw ginseng,water extract,alcohol extract and dry extract powder,were established.The recoveries of pesticides in solid samples(raw ginseng,extraction residues,etc.)and liquid samples(water extract,alcohol extract,etc.)were in the range of 63.4%-110.4%and 62.0%-119.8%,respectively,with relative standard deviations(RSD)less than 20%.The limits of quantification of solid samples and liquid samples were 5-10 ng/g and 0.5-2 ng/mL,respectively.The two sample pretreatment methods were simple,rapid and economical,and met the requirements of multi-residue analysis of pesticides.2.Pesticide transfer regularity study:Ginseng samples with pesticide residues were used to simulate the commonly used Chinese herbal medicine processing(water extraction,alcohol extraction,water-extraction and alcohol-precipitation method,vacuum drying,freeze drying and spray drying).The pesticide residues in each stage of ginseng products were determined to calculate the pesticide transfer rates and processing factors.It was found that in the process of water extraction,most of the pesticide residues were transfer to the extraction residue,the transfer rates of 4 pesticides in the water extraction were in the range of 40%一 80%.In the process of alcohol extraction,almost all pesticides were transferred into alcohol extraction solution,and the transfer rates of 27 pesticides in alcohol extraction solution were in the range of 80%一 100%.The total amount of pesticides did not change much during the concentration process,but the residue level of most pesticides in ethanol extract increased.In the process of water extraction and alcohol precipitation,most of the pesticides were transferred to the supernatant,and there was almost no pesticide transfer in the precipitation.The level of pesticide residues in water extract dried powder was reduced,while that in alcohol extract dried powder was increased.The risk of pesticide residues in spray drying powder was significantly lower than that in vacuum drying powder and freeze drying powder.In general,the water extraction-concentration-spray drying processing method,with all pesticide transfer rates less than 10%and processing factor less than 1,is the ginseng processing method with low pesticide residue risk.3.Pesticide removal research:By designing orthogonal test,the optimal parameters of supercritical carbon dioxide extraction method were optimized as temperature 60℃,pressure 300Bar,time 30min,10%ethanol as modifier agent,and the average pesticide removal rate was 73.0%.At the same time,the results of TLC showed that the types of saponins did not change substantially before and after extraction,and the results of HPLC showed that the retention rate of total saponins after extraction was 96.0%.Moreover,in the extraction process,carbon dioxide is used as the extraction agent and 10%ethanol is used as the modifier agent.After extraction,the solvent is easy to volatilize and will not cause the problem of harmful solvent residue.Therefore,it is an ideal pesticide residue removal process.In addition,the pesticide content of raw ginseng pieces after extracted,extraction liquid and carbon dioxide tail gas was determined,and it was found that 53.2%of the pesticides were transferred to the extraction liquid on average.It is suggested that the pesticide residues should be paid attention to when using supercritical carbon dioxide extraction method to extract the volatile oil from ginseng,and further pesticide removal should be carried out if necessary.