Studies On Authenticity Identification Of Tea Using Multi-platform Omics Strategy

Tea is a high value-added agricultural product.There are many difficulties in identifying the true attributes of teas.Based on multi-analysis platform and chemometric analysis strategy(PCA,PLS-DA,OPLS-DA,LDA,HCA etc.),this dissertation carried out studies on the identification method of different kinds of teas and Tieguanyin teas of different seasons(spring and autumn tea in 2013),different years(autumn tea in 2012 and 2013),and different origins(Anxi in Fujian,Shaoguan in Guangdong,Xianfeng in Hubei,and Zhuzhou in Hunan Province).This dissertation aims to study the relationship between the real attributes of tea and its inherent quality,and to establish a preliminary traceability identification method of tea.The results are as follows:1.A non-targeted metabolomics analysis method for soluble substances in tea based on the UPLC-Q-TOF/MS platform was established and characterized.107 metabolites were identified.The platform was used to discriminate and analyze different kinds of tea based on the chemometric analysis.The results show that the discrimination accuracy of green tea,white tea,oolong tea,black tea and dark tea is 95%,and that of Fu brick tea,Pu'er tea,southern Fujian oolong tea,northern Fujian oolong tea,Dahongpao,and northern Fujian narcissus is 100%.In traceability identification of Tieguanyin,the discrimination accuracy of Tieguanyin produced in different seasons,different years and different geographical origins is100%.2.An analytical method for the determination of 21 free amino acids in tea based on the pre-column derivatization UPLC-MS/MS platform was established and characterized.The results show that the discriminant accuracy of green tea,white tea,oolong tea,black tea and dark tea is 100%;the discriminant accuracy of Anxi Tieguanyin produced in different seasons and Tieguanyin produced in different geographical origins is 100%.3.A method for the determination of five free sugars in tea based on the HILIC-MS platform was established and characterized.Combining with the chemometric analysis,the traceability identification of tea was studied.The results show that the discriminant accuracy of green tea,white tea,oolong tea,black tea and dark tea is 79.7% and the discriminant accuracy of Anxi Tieguanyin produced in different seasons and Tieguanyin produced in different geographical origins is 100%.4.A method for the determination of 36 elements in tea based on the ICP-MS platform was established and characterized.The traceability identification of Tieguanyin was studied by combining chemometric analysis.The results show that the discriminant accuracy of Anxi Tieguanyin in different seasons is 100%,and that of Tieguanyin produced in different seasons and different geographical origins are 87% and 98%,respectively.5.The stable isotope ratios of carbon,nitrogen,hydrogen and oxygen in tea were determined by the EA-IRMS platform.Combined with chemometrics,the identification of Tieguanyin tea was studied.The results show that the discriminant accuracy of Anxi Tieguanyin produced in different seasons and Tieguanyin produced in different geographical origins is 100%.