title: Determination and quality evaluation of green tea extracts through qualitative and quantitative analysis of multi-components by single marker (QAMS).
abstract: The quality of tea is mainly attributed to tea polyphenols and caffeine. In this paper, a new strategy for quality evaluation of green tea extracts was explored and verified through qualitative and quantitative analysis of multi-components by single marker (QAMS). Taguchi Design was introduced to evaluate the fluctuations of the relative conversion factors (fx) of tea catechins, gallic acid and caffeine to epigallocatechin gallate. The regression model (Sig.=0.000) and the deviations (R(2)>0.999) between QAMS and normal external standard method proved the consistency of the two methods. Hierarchical cluster analysis and canonical discriminant analysis were employed to classify 26 batches of commercial Longjing green tea extracts (LJGTEs) collected from different producers. The results showed a significant difference in component profile between the samples from different origins. The QAMS method was verified to be an alternative and promising method to comprehensively and effectively control the quality of LJGTEs from different origins.
authors.affiliation: Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
authors.forename: Da-Wei
authors.initials: DW
authors.lastname: Li
authors.affiliation: Zhejiang Institute for Food and Drug Control, Hangzhou 310051, China. Electronic address: zhumingd@hotmail.com.
authors.forename: Ming
authors.initials: M
authors.lastname: Zhu
authors.affiliation: Skyherb Ingredients, Anji 313300, China.
authors.forename: Yun-Dong
authors.initials: YD
authors.lastname: Shao
authors.affiliation: Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Shen
authors.affiliation: Skyherb Ingredients, Anji 313300, China.
authors.forename: Chen-Chen
authors.initials: CC
authors.lastname: Weng
authors.affiliation: Department of Chemistry, Zhejiang University, Hangzhou 310027, China. Electronic address: yanweidong@zju.edu.cn.
authors.forename: Wei-Dong
authors.initials: WD
authors.lastname: Yan
mesh_terms: D002110:Caffeine / Q000032:analysis*; D002392:Catechin / Q000031:analogs & derivatives* / Q000032:analysis; D063427:Food Quality; D005707:Gallic Acid / Q000032:analysis*; D013662:Tea / Q000737:chemistry*
chemical_list: D013662:Tea; D002110:Caffeine; D005707:Gallic Acid; D002392:Catechin; C045651:epigallocatechin gallate
keywords: Caffeine (PubChem CID: 2519); Catechin (PubChem CID: 73160); Catechin gallate (PubChem CID: 6419835); Determination; Epicatechin (PubChem CID: 72276); Epicatechingallate (PubChem CID: 367141); Epigallocatechin (PubChem CID: 72277); Epigallocatechin gallate (PubChem CID: 65064); Gallic acid (PubChem CID: 370); Gallocatechin (PubChem CID: 65084); Gallocatechin gallate (PubChem CID: 199472); Green tea extracts; HPLC; Qualitative and quantitative analysis of multi-components by single marker (QAMS); Quality evaluation; Taguchi Design