Impact of prolonged withering on phenolic compounds and antioxidant capability in white tea using LC-MS-based metabolomics and HPLC analysis: Comparison with green tea

Abstract

Contents of 20 bioactive compounds in 12 teas produced in Xinyang Region were determined by high performance liquid chromatography. Ultra-high performance liquid chromatography-quadrupole time of flight-mass spectrometry was developed for untargeted metabolomics analysis. Antioxidant activities were measured by 4 various assays. Those teas could be completely divided into green and white tea through principal component analysis, hierarchical cluster analysis and orthonormal partial least squares-discriminant analysis (R²Y = 0.996 and Q² = 0.982, respectively). The prolonged withering generated 472 differentiated metabolites between white and green tea, prompted significant decreases (variable importance in the projection > 1.0, p-value < 0.05 and fold change > 1.50) of most catechins and 8 phenolic acids to form 4 theaflavins, and benefited for the accumulation of 17 flavonoids and flavonoid glycosides, 8 flavanone and their derivatives, 20 free amino acids, 12 sugars and 1 purine alkaloid. Additionally, kaempferol and taxifolin contributed to 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability of white tea.

Keywords: (−)-Epigallocatechin gallate (PubChem Compound CID: 65064); 1,3,7-Trimethyluric acid (PubChem Compound CID: 79437); Antioxidant activities; Caffeine (PubChem Compound CID: 2519); Flavonoids; Isotheaflavin 3'-gallate (PubChem Compound CID: 135704008); Kaempferol (PubChem Compound CID: 5280863); LC-MS metabonomics; Luteolin (PubChem Compound CID: 5280445); Quercetin (PubChem Compound CID: 5280343); Taxifolin (PubChem Compound CID: 24887336); Theaflavin (PubChem Compound CID: 4263901); Theaflavin 3,3'-digallate (PubChem Compound CID: 136277567); Theaflavins; White tea.