Dissipation Dynamics Of Tebuconazole In Pear During Storage Process

Studying the residual behavior of pesticide residues in the storage of pear products is an important basis for scientific evaluation of its food safety.In this paper,the characteristic fruit of Dangshan Pear in Dangshan County,Anhui Province is taken as the pear fruit,and the residue analysis method of the common fungicide tebuconazole in the whole fruit,pear peel and pear flesh of Dangshan Pear is established.The residual dissipation dynamics of crisp pears at room temperature storage and cold preservation,and their risk levels and metabolic rules were clarified.The results will provide a technical basis for risk warning and control of pear storage and market segment fungicides.1.Method for analysis of tebuconazole in Dangshan pearPear whole fruit,pear peel and pear flesh samples were extracted,purified and determined by HPLC using QuEChERS method.The recovery experiment showed that the addition recovery of tebuconazole in pear whole fruit was 76.5-107.4%and the relative standard deviation was 1.29-2.33%;at the addition levels of 0.2 mg/L,0.5 mg/L and 5.0 mg/L the recovery in the pear peel was 93.2-104.9%,the relative standard deviation was 0.77-1.53%;the recovery in the pear flesh was 84.7-111.7%,and the relative standard deviation was 1.06-1.95%.The linear relationship of the method was good,the correlation coefficient was 0.9999,and the LOQ of tebuconazole was 0.05 mg/L,indicating that the residue analysis method met the requirements of the Pesticide Residue Test Guidelines.2.Residual dissipation dynamics of tebuconazole on Dangshan pear during storage at room temperatureThe residual dissipation dynamics of tebuconazole in the storage of Dangshan Pear at room temperature showed that the dissipation dynamics of tebuconazole in pear whole fruit,pear peel and pear flesh accorded with the first-order dynamic equation;after the recommended dose of fruit,pear whole fruit.The original deposition amounts of tebuconazole in pear peel and pear flesh were 0.58 mg/kg,10.39 mg/kg,and 0.12 mg/kg,respectively,and the half-lives were 8.8 d,9.4 d,and 9.4 d,respectively;The original deposition amounts of tebuconazole in pear fruit,pear peel and pear flesh were 0.71 mg/kg,12.42 mg/kg and 0.22 mg/kg,respectively,and the half-lives were 9.5 d,8.2 d and 9.4d,respectively.It can be seen that tebuconazole degraded rapidly during storage at the temperature of Dangshan Pear.At the initial stage of storage at room temperature,the residual amount of tebuconazole in pear flesh increased,mainly due to the migration of tebuconazole in pear peel to pear flesh.3.Residual dissipation dynamics of tebuconazole on Dangshan pear during cold storageThe residual dissipation dynamics of tebuconazole in the storage of Dangshan Pear during low temperature storage showed that the low temperature significantly affected the dissipation rate of tebuconazole on Dangshan Pear,and its half-life was greater than 90 d.After storage for 180 days,the residual amounts of tebuconazole in pear whole fruit,pear peel and pear flesh were 0.31-0.61 mg/kg,2.92-8.18 mg/kg and 0.14-0.24 mg/kg,respectively,and the dissipation rate reached 17.24-77.31%.It can be seen that the residual amount of tebuconazole is mainly concentrated on the pear peel,and the waxy layer of the pear fruit epidermis is the main reason for the relatively high residual amount of pear peel.Compared with storage at room temperature,the half-life of tebuconazole in pear fruit is longer when refrigerated and preserved,and the pear fruit can be kept longer.However,because it has a slower residual dissipation during the cold storage process,it is recommended to use a low-temperature storage method to preserve pear fruit.After 100d,peeled and eaten.