Correlation Analysis between Mineral Elements Content and Quality Ingredients of Flat Green Tea

In order to explore the correlation between mineral elements content and quality ingredients of flat green tea, ten representative flat green tea samples from five production areas (Dawu County, Hubei Province, Pan'an County, Zhejiang Province, She County, Anhui Province, Meitan County, Guizhou Province and Emeishan City, Sichuan Province) were collected. The content of nine mineral elements (Mg, K, Ca, P, Al, Mn, Fe, Zn, B) and five quality ingredients (water extracts, tea polyphenols, free amino acids, total soluble sugars, caffeine) were determined. Results showed that the mineral elements influenced each other and existed with synergistic or antagonistic effects. The water extracts content was significantly negatively correlated with the B content (P<0.05), the tea polyphenol content was extremely negatively correlated with Fe content (P<0.01), the total soluble sugar content was significantly positive to the B content (P<0.05), but negatively correlated with Mg and Ca content (P<0.05), Fe and Mn had a negative effect on caffeine content. The principal component analysised exhibited that the first three principal components explained 89.00% of the cumulative variance contribution, Mg, Ca, Zn, Al and P were considered as characteristic elements of flat green tea, water extracts content and free amino acids content were considered as important physicochemical indicators to evaluate the quality of flat green tea. Cluster analysis showed that samples from the same producing area were grouped together, and samples from different producing areas were clearly separated, indicated that the quality of flat green tea showed distinct regional distribution characteristics.