摘要
[目的]了解饮用茶水中硝酸盐与亚硝酸盐含量动态变化特征。[方法]测定不同茶叶品种、冲泡放置时间、沸腾时间以及冲泡方式下茶叶的硝酸盐和亚硝酸盐含量变化情况。[结果]3种茶叶中,硝酸盐质量浓度大小顺序为红茶>绿茶>龙井茶,亚硝酸盐质量浓度大小顺序为绿茶>红茶>龙井茶。不同放置时间下,绿茶硝酸盐质量浓度先缓慢上升,再直线上升,最后又缓慢下降,1 min时最低,为0.187 mg/L,720 min时最高,为1.230 mg/L;亚硝酸盐质量浓度变化趋势不明显,180 min时最低,为0.060 mg/L,1 440 min时最高,为0.130 mg/L。不同沸腾时间对绿茶硝酸盐和亚硝酸盐质量浓度的影响不大,硝酸盐质量浓度范围为0.180～0.220 mg/L,亚硝酸盐质量浓度范围为0.102～0.130 mg/L。密闭条件下冲泡的茶水中硝酸盐和亚硝酸盐含量均高于敞开方式下冲泡的。[结论]冲泡茶叶后应在30～180 min内饮用;冲泡茶叶时最好选择敞开方式。
[ Objective ] The change character of nitrate and nitrite content in tea water was researched. [ Method ] The change of nitrate and nitrite in tea water of different tea varieties, different soaking times, the different boiling times and the different brewing methods was analyzed. [ Result] The order of concentration of nitrate in tea water from high to low was black tea 〉 green tea 〉 Longjing tea, and order of concentra- tion of nitrite in tea water, green tea 〉 black tea 〉 Longjing tea. In the different soaking times,the concentration of nitrate was slowly increased, then, fast raised, and finally slowly decreased, and the minimum value （0. 187 mg/L） appeared at 1 minute and in the highest value （ 1. 230 mg/L） at 720 minutes ; and there was no obvious variation in the concentration of nitrite with the lowest value of 0.060 mg/L at 180 minutes and the highest value of 0.130 mg/L at 1 440 minutes. Further more, The boiling water time did not significantly affect the concentration of nitrate and nitrite, with the concentration of nitrate： 0.18 -0.22 mg/L and nitrite： 0. 102 -0. 130 mg/L. The concentration of nitrate and nitrite was higher in the closed mode of tea-soaking than the opening mode of tea-soaking. [ Conclusion ] The tea water should be drunk within 30 minutes after its making and the best tea-soaking was the opening mode of tea-soaking.
出处
《安徽农业科学》
CAS
北大核心
2009年第35期17315-17317,共3页
Journal of Anhui Agricultural Sciences
基金
重庆工商大学创新基金项目(083021)
重庆工商大学青年基金项目(0852005)
