Study On The Pesticide Residue Transferring From Jasmine To Tea-base And Factors Interrelated During Scenting Processes

The pesticide residues transferring from jasmine to green tea-base during scenting process were studied in this thesis for the first time, and the interrelated factors such as pesticide concentration, pesticide kinds, scenting times, isolated scenting , baking and tea-base moisture were also discussed. The dynamic experiment of fenvalerate , cypermethrin and methamidophos residue on jasmine was conducted .The mechanism and pesticide residue in jasmine tea were discussed. And a suggestion on the banning of use of pesticides such as fenvalerate and dicofol on jasmine plant was proposed. The main results are as follows.The pesticide residues transferring from jasmine to green tea-base occurred during scenting process. And the pesticide residues in jasmine tea increased with pesticide concentration ,and the increasing of scenting times. It's a good way to prevent pesticide residue transferring by isolated scenting if the jasmine tea's aroma is good too. We also found that different pesticides had different effect on pesticide residue transferring. For example ,there is a significant amounts of fenvalerate transferred from jasmine ,however methamidophos is not so much and the amounts in jasmine tea is not detected. The baking step showed different effects on various pesticides, under the simulated condition ,the baking step can reduce 95% quantities of methamidophos in tea ,however, for fenvalerate only 5%. The results showed that tea moisture had obvious effect on residue transferring, the amounts of pesticide residue transferring increased with the increasing moisture absorbing in tea-base .That is to say tea-base with low moisture may content a high quantities of pesticide residue due to the higher absorption of moisture. The dried jasmine34flower amounts in jasmine tea showed obvious effect on pesticide residue in jasmine tea, and it depended on the amounts of dried jasmine flower and its pesticide residue. A suggestion that banned to use these pesticides such as fenvalerate and dicofol on jasmine plant was proposed. Results indicated that pesticide residues is transferred mainly not by the pesticide volatilization, but by the capillarity phenomenon of water transferring from jasmine flower to tea-base. However ,the mechanism of pesticide translation need to be further studied.