Analysis Of Mineral Elements Content Of Black Tea From Different Origins And Their Origin Characteristics

Mineral element is an important part of the quality of black tea,and the study of mineral elements is helpful to the identification and quality identification of tea origin.25 mineral elements in 52 congou black tea and broken black tea samples produced from 5 countries were analyzed by inductively coupled plasma optical emission spectrometry(ICP-OES)and inductively coupled plasma mass spectrometry(ICP-MS),respectively.The principal component analysis(PCA)and cluster analysis were used to discriminate the origins of black tea samples,that showed the origin characteristics and variation tendency in the contents of 25 mineral elements.The sensory evaluation was also used to investigate the relationship between the mineral elements and the quality of black tea.Mineral elements in black tea samples from different countries displayed that the contents of K,Ca and P elements in black tea were apparently higher than other elements,the content was 1.511×104-1.856×104mg/kg,3877-6773mg/kg,and 3262-4699mg/kg,respectively.The rest elements from high to low was Mg,Al,Mn,Fe,Si,and Na.Five principal components was obtained for the statistical analysis of five different countries,the elements Al,Fe,V,K,Ni,Cu,Ba and Na were the major influence factors.The results showed that the effect of principal component analysis was superior to the cluster analysis,mineral elements in black tea could be used as the reference for the origin identification of black tea.Combined with the sensory evaluation of black tea quality,the contents of mineral elements in the domestic and foreign tea samples were analyzed.The results showed that there was a significant difference in content of element Al,Fe,Zn between Yunnan black tea and black tea from other regions,the content of K element of Keemun black tea has significant differences to other regions,and the content of Mn element of Sri Lankan black tea was extremely significant differences with other regions.The content of Ca,Al,Pb elements were reducing as the level of black tea was raised,K,Na,Zn,Cu,Ni elements were on the contrary.Elements K,P,Na,Zn,Cu and Ni were positively correlated with the quality of black tea,while Ca,Al,Mn,Ba,Pb were negatively correlated with the tea quality.However,any two elements in the 8 elements Al,Fe,V,Co,Li,Cr,Pb,As showed significantly positive correlation.