摘要
在所采集的133个茶样中,其含硒量范围处于0.021～0.774 ppm(最高值4.320ppm,最低值0.017 ppm);茶叶含硒量数据的分布特征,属于对数正态型,它的几何平均值为0.129 ppm,影响茶硒素浸出率的因子有:冲泡水温和冲泡次数,而冲泡方式(保温及平衡时间等)对茶叶硒素浸出率影响不大。茶叶硒素含量高低主要受茶园土壤母岩或地层的影响,本研究结果表明,我国富硒岩层出现在古生代二叠纪和寒武—奥陶纪的硅质页岩等岩层(如湖北省恩施、鹤峰、宣思、咸丰和陕西省紫阳县),我国南方茶园绝大部分母岩的含硒量较低;高硒茶均产于富硒岩层发育的茶园。
On the basis of field investigation,133 samples of tea were collected from South China and other coutries.Se content in tea,as well as soils and parent or bed rocks of the tea gardens were determinated.The correlation of Se content in tea to that of soil and parent rock,and the effect of tea making conditions on Se extraction rate were studied.The major conclusions are as follows:(1)Most of the Se content in tea samples ranged from 0.021 fppm to 0.774 ppm(the highest was up to 4.320 ppm,the lowest was as low as 0.017 ppm),the data of which were in logarithmic normal distribution type,and the geometric average value of them was 0.129 ppm.In most tea samples under study the Se content was lower than 0.150 ppm.(2)conditions of tea making proccess afecting Se extraction rate were a)the temperature of tea making water,the most effective regime was around 92℃,b)Se extraction rate decceases gradually in the ucceeding tea make proccess;c)the duration of extraction in tea making had little effect on Se extraction rate.?It was found that Se content in parent rock would be the essential factor affecting Se content in tea.The high Se content in tea was always originated from Se-rich parent rock,such as siliceaus shale and carbonaceous shale of Permian period.
关键词
茶叶
硒
浸出率
土壤母质
含量
tea
selenium
extraction rate
soil parent material
