凤凰茶中硝酸盐与亚硝酸盐的含量测定

Determination of Nitrite and Nitrate Contents in Fenghuang Tea

[目的]研究凤凰茶中硝酸盐和亚硝酸盐的含量,为凤凰茶的安全饮用提供科学依据。[方法]利用分光光度法对广东省潮州市凤凰山区生产的3批21个茶叶样品的硝酸盐和亚硝酸盐含量进行测定。[结果]结果表明,3批茶叶21个样品中,硝酸盐的含量在1445.01～4623.99mg/kg,含量最低的是第1批茶发酵4h后的样品,含量最高的是第3批茶叶中的成品茶;亚硝酸盐含量在3.56～6.87mg/kg,含量最低的是第1批茶样发酵6h后的样品,含量最高的是第2批茶叶中的成品茶。[结论]不同茶园的茶叶,硝酸盐和亚硝酸盐含量有较大差别,海拔1200m茶园茶叶硝酸盐和亚硝酸盐含量较低,海拔10m左右茶园茶叶硝酸盐和亚硝酸盐含量较高;同一茶园不同采收时间茶叶随时间延长硝酸盐含量增加,亚硝酸盐含量差别不大;硝酸盐含量随发酵时间不同变化不大,亚硝酸盐含量随发酵时间而变化。

[ Objective]The aim was to study nitrate and nitrite contents in Fenghuang tea and provide science basis for people＇s safety drink- ing. [ Method] Nitrate and nitrite contents in 21 Fenghuang tea samples from Chaozhou were determined by spectrophotometry. [ Result] The nitrate contents in 3 batches 21 samples of Fenghuang tea ranged from 1 445.01 to 4 623.99 mg/kg, the fermented tea-like 4 hours of batch 1 had the lowest content of nitrate and the finished product of batch 3 had the highest content of nitrate. The contents of nitrite of that ranged from 3.56 -6.87 mg/kg, the fermented tea - like 6 hours of batch 1 had the lowest content of nitrite and the finished product of batch 2 had the highest content. [ Conclusion]The contents of nitrate and nitrite in Fengbuang tea from different tea plantation had significant differences. Nitrate and nitrite contents were lower from height above sea level 1200 m and higher from height above sea level 10 m. Nitrate content of Fenghuang tea from same tea plantation increased as harvesting time goes on, and content of nitrite had no significant difference. Nitrite content changed as fermented time goes on, and nitrate content had not quite different.