Elements characterization of Chinese tea with different fermentation degrees and its use for geographical origins by liner discriminant analysis

摘要

Elements profiling of teas are very important not only for quality control of tea, but also providing comprehensive database for risk assessment of human health. 33 elements in 313 tea samples collecting from representative provinces of China were analyzed. The levels of elements varied with different tea types. Puerh tea had the highest mean concentrations of Al (862 +/- 405 mg kg(-1)), Cr (2.51 +/- 1.6 mg kg(-1)), As (0.14 +/- 0.10 mg kg(-1)), Mg (2313 +/- 830 mg kg(-1)), Cs (0.56 +/- 0.63 mg kg(-1)) and REEs (1.33 +/- 1.0 mg kg(-1)) and lowest mean levels of Co (0.22 +/- 0.11 mg kg(-1)), Ni (6.27 +/- 3.4 mg kg(-1)), Zn (33.8 +/- 11 mg kg(-1)) and Pb (0.81 +/- 0.74 mg kg(-1)) compared to green teas and black teas. However, the highest mean levels of Ni (14.5 +/- 13 mg kg(-1)), Cu (24.6 +/- 12 mg kg(-1)), Zn (52.7 +/- 18 mg kg(-1)), Mo (0.28 +/- 0.14 mg kg(-1)) and Pb (1.16 +/- 0.86 mg kg(-1)) were found in black teas. Green teas were measured with lowest contents of elements among three types of teas. High recognition (98.4%) and satisfactory predictive ability (97.8%) were achieved for three types of tea with different fermentation degrees by liner discriminant analysis. Moreover, black teas from five different regions could be easily distinguished with each other based on the elements with significant differences.