Study On Transfer Behavior And Risk Assessment Of Pesticide Residues During The Preparation And Processing Of Lycii Fructus Extract

Lycii Fructus is a famous medicinal and edible homologous material.With the increase of its planting area,its diseases and insect pests are gradually aggravated.So,the pesticides are widely used,resulting in the serious pesticide residues in wolfberry fruits.A lot of reports on detection methods and limit standards on pesticide residues of Lycii Fructus have been reported.However,the detection of pesticide residues in Fructus Lycii extract and the samples during processing have not been reported.Therefore,it is of great significance to explore the transfer behavior of pesticide residues in different processes of wolfberry,and to evaluate the risk of dietary exposure of products prepared by different processes.Firstly,the UFLC-MS/MS method was established for the detection of 43 pesticide residues in fruits and various extracts of Lycium barbarum.The samples were purified by acetonitrile extraction and dispersive solid phase extraction,the mobile phase of chromatographic system was eluted by acetonitrile-water gradient,and the mass detected system was set by Schedule MRM mode.The results of method validation showed that there was a good linear relationship in the range of 0.0005-0.2 mg/kg,the correlation coefficient r>0.99.The RSDs of precision were less than 6%(parathion 15%),and the RSDs of repeatability were less than 10%.The recovery ranged was from 75%to 115%(carbendazim 63%--80%).The method met the requirements of pesticide residue detection and is suitable for the detection in wolfberry fruits and its extracts.Using the established UFLC-MS/MS analysis method,the pesticide residues were detected in the wolfberry intensified with 43 pesticides and its various extracts.The results showed the pesticide residues decreased 98.17%,66.38%and 41.82%,respectively,in the sample using water extraction with alcohol precipitation,and the sample with water extraction,and the sample with ethanol extraction,as compared with the pesticide intensified fruits,which showed that the preparation has obvious removal effects on pesticide residues.Both processing factors of water extract and ethanol extract are 0.49 and 0.80,suggesting that water extraction is better for the removal of pesticide residues.After the water extraction with alcohol precipitation,the residual pesticides almost completely transferred to the alcohol supernatant,of which in the precipitation was very low.The concentration and drying had little effect on the processing factors.The transfer behavior of pesticide residues is not only related to their physical and chemical properties,but also related to the processing technology,which,will reduce the level of pesticide residues significantly with good processing method.Based on our previous results and literature review,four pesticides(acetamiprid,imidacloprid,carbofuran and 3-hydroxycarbofuran)were chosen to prepare pesticide intensified wolfberry,which were used to research transfer behavior of pesticide residue in different processing.The study on tea brewing experiment showed that the dissolution of residual pesticides displayed Weibull distribution,the amount of each brewing was about 1/3 of the residual in the residue.The leaching amount of residual pesticides in tea soup with cover was higher than that without cover.Therefore,the intake of pesticide residue in wolfberry can be reduced by using reasonable brewing method.As compared with the previous experimental results,the transfer behavior of the same pesticide under the same preparation showed the same transfer trend,indicating that the interaction among the pesticides during processing was very small.The point assessment model was used to assess the dietary exposure risks of various Lycii Fructus and their extracts.The assessment values of the long-term and acute dietary risks in the fruits of different grades(organic,green,pollution-free,common)of market wolfberry and their extracts were with the scopes of 0.4-4.9%and 0.1-21.5%,respectively,which can conclude that different grades of Lycii Fructus,whether dried fruit or extracts,are safe to eat.The assessments values of the long-term and acute dietary risks in 43 pesticides intensified wolfberry,as well as its extracts with water,ethanol,and water extraction with ethanol precipitate,were 403.8%,156.0%,274.7%,6.0%and 548.6%,121.9%,397.6%,3.3%,respectively.Meanwhile,the assessment results in 4 pesticides(acetamiprid,imidacloprid,carbofuran and 3-hydroxycarbofuran)intensified wolfberry,as well as its extracts were 103.7%,59.5%,90.5%,8.1%and 504.8%,287.5%,439.8%,38.8%,respectively.It can be seen that the processing can significantly reduce the dietary risk of pesticide residues.If good technology was used to process the wolfberry which intensified with 43 pesticides and exceeded 10 times the pesticide limit,the acute and longterm dietary risks can be reduced by 67 times and 166 times,respectively,and can reach the acceptable risk level of dietary.This study not only provides a scientific basis for the normal use of Lycii Fructus,but also provides a reference for the application of other medicinal and edible homologous substances.