Digestion Dynamics Of Pyridaben On Kiwifruit, Risk Assessment And Processing Residues In Kiwifruit

This experiment establishes a fast,simple and effective method for the analysis of pyridaben residues in kiwifruit.Kiwifruit samples were extracted with acetonitrile,purified by octadecylsilane,and detected by LC-MS/MS.The daily recovery rate was78.53?98.00% with the coefficient of variation(RSD)of 0.86?6.11%;the daily recovery rate is 74.93?96.74% with RSD of 0.54?10.82%.The detection limit(LOD)and the limit of quantification(LOQ)was 0.012 mg/kg and 0.004 mg/kg,respectively.The linearity,the accuracy and the precision of established method reached the standard for the analysis of pesticide residues.In 2018,field trials of 15% pyridaben EC in kiwifruit were conducted in Guizhou,Sichuan,Anhui,Zhejiang,Guangxi and Jiangsu.The field trials results showed that the degradation half-life of pyridaben on kiwifruit was 7.07-7.37 d.All terminal residues of pyridaben in kiwifruit were below the maximum residue limit set by the European Union(0.5mg/kg).However,the residues of most samples treated with the high dose exceeded the maximum residue limit(0.1mg/kg)set by Japan.Furthermore,the dietary risk of pyridaben on kiwifruit was evaluated based on the final residues of pyridaben and the data of body weight and fruit intake of different age groups in the “Residential and Health Status Survey of Chinese Residents”.The results showed that both the acute intake risk(RQa)and chronic intake risk(RQc)were far below 100%,indicating that the chronic and acute toxicity caused by pyridaben residue in kiwifruit were relatively acceptable to Chinese.In addition,the variations of the content of pyridaben in conventional fruit and vegetable processing methods were explored.The removal effects of three processing methods;such as;peeling,juice extraction and drying,on the residue of pyridaben on kiwifruit were investigated.The results showed that the processing factors of the peeling,juicing,and drying processes were 0.15,0.51,and 1.05,respectively,indicating that peeling and juicing could reduce the residue of pyridaben.However,dry heat treatment process increased the residue of pyridaben because of heating and concentration.In this thesis,we monitored the residues of pyridaben in kiwifruit from administration to consumption.The results may help to understand the impact of pyridaben EC on the ecological environment and the risk to human health.The data may help the Chinese government to formulate the maximum residue limit of pyridaben in kiwifruit.The elimination effect of pyridaben on kiwifruit during processing may provide experimental data support for the reasonable processing of kiwifruit products in households and businesses.