沏茶方式对其微量元素的影响

Effect of way of infusing tea on elements in tea

采用原子吸收光谱法,以龙井、碧螺春、安徽祁红和云南滇红4种茶叶为研究对象,研究不同冲泡温度、次数对其茶汤中钾、钠、锰、铁、锌、铜、钙、镁8种元素含量及溶出率的影响。结果表明,不同种类的茶叶中所含的微量元素有一定的差异,且不同处理对茶叶中微量元素溶出率有显著差异,其溶出率以第一道茶汤最高(41.3%～92.9%),且元素溶出率随冲泡次数的增加而降低,第三道茶汤溶出率只有0～34.9%。此外水温对K的溶出率影响不大,Na在100℃时溶出率最大;Mn在90℃时溶出率最大。绿茶中Fe、Cu在70℃时的溶出率最大,Zn、Ca、Mg在80℃时溶出率最大。而红茶中Fe、Zn、Cu、Ca、Mg在90℃时溶出率达到最大值。

The effect on contents and dissolution rates of potassium （ K）, sodium （ Na）, manganese （ Mn）, iron （ Fe）, zinc （Zn）, copper （ Cu）, calcium （Ca） and magnesium （ Mg ） in Longjing, Biluochun Anhui qihong and Yunnan dianhong were investigated under the different temperature and preparation times by atomic absorption spectrometry.The results showed that the contents of trace elements in different kinds of tea were different,and dissolution rates of elements in teas were significantly different. At the first time, the level of dissolution rate was highest（41.3%-92.9%） ,then it was decreased with the soaking times increased.The dissolution rate of the tea was only from zero to 34.9% at the third time.For the effects of water temperature on the dissolution rates of elements, there was little impact on K under different temperature,and it was the largest for Na at 100℃,and Mn was at 90℃. In green tea,the dissolution rates of Fe and Cu were the largest at 70℃,and Zn,Oa and Mg were at 80℃.On the other hand ,the dissolution rates of Fe,Zn,Cu,Ca and Mg were the largest at 90℃ in red tea.