摘要
对江西省5个茶区的88个茶鲜叶(新叶、老叶)样,以国标方法测定重金属Cu、Pb、Cd、As、Hg、Cr含量。结果显示,老叶、新叶和鲜叶聚类分析结果不完全相同,但均分为5组,无明显自然地域界限,6种重金属聚类组间差异显著(P<0.05);经交叉验证的判别分析,区分老叶与新叶的正确率为87.5%,说明老叶与新叶差异明显,判别新叶是否高山组的正确率为77.3%。以改进的Nemerow综合污染指数(NIPI)评价重金属状况并进行简单对应分析显示,老叶主要为轻度污染,新叶总体未污染,处于警戒水平:赣中赣南茶区新叶安全,其余新叶为警戒水平。结论表明:江西茶鲜叶重金属茶区间有一定差异但自然地域界限不明显;种植环境平均良好,路边组与高山组无明显差异。
Totally 88 fresh tea leaves samples(including new leaves and old leaves) from 5 producing districts in Jiangxi province were analyzed for the contents of Cu,Pb,Cd,As,Hg and Cr according to relevant national standards.The results reveal that cluster groups are not quite the same for new leaves,old leaves and fresh leaves although 5 groups were obtained each,which indicates that there are no clear natural separatrix,but there are significant differences within cluster groups for each heavy metal(P<0.05).By discriminant analysis with leave-one-out cross-validation,87.5% of fresh leaves were correctly discriminated into new or old one for their significant differences,while just 77.3% were correctly discriminated into mountain group or not.By simple correspondence analysis for data of improved Nemerow integrated pollution index(NIPI) of the six metals,old leaves reach to slightly polluted level while just precautious for new leaves with safe for middle and south district in Jiangxi and precautious for others.In conclusion,there is a slight difference among heavy metals in fresh leaves from various producing districts in Jiangxi but without clear natural separatrix.It's good and uniform or similar in natural producing condition in Jiangxi and there are no great differences between mountain group and road one.
出处
《食品与生物技术学报》
CAS
CSCD
北大核心
2012年第1期55-60,共6页
Journal of Food Science and Biotechnology
基金
国家自然科学基金项目(20462005)
关键词
茶鲜叶
重金属
多变量分析
fresh tea leaves,heavy metals,multivariate analysis
