Division of Hill Area Tea Sciences, Institute of Himalayan Bioresource Technology, Palampur (HP), India.
Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2009 Feb;26(2):157-63. doi: 10.1080/02652030802363782.
The objective of this paper is to investigate the loss/stability of neonicotinoids (imidacloprid and acetamiprid) residues during the manufacture of black tea and to study the transfer of these pesticides from made tea to its infusion. For orthodox black tea, the manufacturing process involves leaf harvesting (plucking two leaves and a bud), withering, rolling, fermentation (oxidation), and drying. Initial withering and final drying resulted in the loss of pesticide residues, but no significant reduction in residue levels resulted from the rolling and fermentation steps. The drying process resulted in a residue transfer of 64-70% and 69-74% of the initial level, whereas the brewing process resulted in a residue transfer of 37-39% and 45-49% of imidacloprid and acetamiprid, respectively, from dried tea into the infusion. The decrease in acetamiprid levels during drying was also significant (8-13%), whereas the total loss during the manufacturing process ranged from 26 to 31%. Further, brewing for longer periods (an extended brewing time) resulted in higher transfer (up to 44% for imidacloprid and 53% for acetamiprid) of pesticides to tea infusion. Further, the extent of pesticide leaching depends on its water solubility, partition coefficient, and the brewing time.
本文旨在研究在红茶制作过程中，新烟碱类杀虫剂（吡虫啉和噻虫胺）残留的损失/稳定性，并研究这些农药从制成的茶叶向其浸出液中的转移情况。对于传统红茶，其制作过程包括叶片采摘（两片叶和一个芽）、萎凋、揉捻、发酵（氧化）和干燥。初始萎凋和最终干燥导致农药残留损失，但揉捻和发酵步骤并未导致残留水平显著降低。干燥过程导致残留转移了初始水平的 64-70%和 69-74%，而冲泡过程导致残留从干茶中转移到浸出液中的吡虫啉和噻虫胺分别为 37-39%和 45-49%。在干燥过程中，噻虫胺水平的下降也很显著（8-13%），而在整个制造过程中的总损失范围为 26%至 31%。此外，冲泡时间延长（冲泡时间延长）会导致更多的农药（吡虫啉高达 44%，噻虫胺高达 53%）转移到茶浸出液中。此外，农药浸出的程度取决于其水溶性、分配系数和冲泡时间。
