GC–MS and LC-MS/MS metabolomics revealed dynamic changes of volatile and non-volatile compounds during withering process of black tea. (1st June 2023)

• Record Type: Journal Article
• Authors: Fang, Xin; Liu, Yanan; Xiao, Jingyi; Ma, Cunqiang; Huang, Youyi
• Is Part Of: Food chemistry. Volume 410(2023)
• Publication Date: 2023-06-01
• Subjects: Camellia sinensis -- Volatile organic compounds (VOCs) -- Aroma formation -- Characteristic metabolites -- Kaempferol, quercetin and their glycosides; HPLC High-performance liquid chromatography -- HS-SPME-GC–MS Headspace solid-phase microextraction-gas chromatography-mass spectrometry -- VOCs Volatile organic compounds -- LC-MS/MS Liquid chromatography-mass spectrometry/mass spectrometry -- OPLS-DA Orthonormal partial least squares-discriminant analysis -- FTL, or XY Fresh tea-leaves -- WTL Withered tea-leaves; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2023.135396
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: HS-SPME/GC–MS, UHPLC-Q-Exactive HF/MS determine volatiles, non-volatiles in black tea. 118 VOCs and 648 metabolites were detected in withered and processing tea-leaves. Several key aroma-active volatiles (OAV > 1.0) for aroma formation significantly increased. Hydrolyzation, O -methylation of kaempferol-, quercetin glycosides form methoxyl flavonoids. N -acylation catalyzed by N -acyltransferase promote accumulation of N -acylated amino acids. Abstract: High-performance liquid chromatography (HPLC), headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC–MS) and ultra-high performance liquid chromatography–Q-Exactive HF-X mass spectrometer (UHPLC–Q-Exactive HF/MS) were carried out to reveal dynamic changes of volatile and non-volatile compounds during the withering process of black tea. A total of 118 volatile organic compounds (VOCs) and 648 metabolites were identified in fresh and withered tea-leaves, respectively. Among them, 47 VOCs (OAV > 1.0) for the aroma formation, and 46 characteristic metabolites (VIP > 1.50, p < 0.01) selected through orthonormal partial least squares-discriminant analysis, indicated the withering contribution during black tea processing. Overall, the withering promoted alcohols, aldehydes, phenols, heterocyclic oxygen, hydrocarbons and halogenated hydrocarbons through relevant hydrolyzation, decomposition, terpene synthesis, and O -methylation. The hydrolyzation, O -methylation, condensation and N -acylation of kaempferol glycosides, quercetin glycosides, ester catechins, and gallic acid generated the accumulation of methoxyl flavonoids and flavonoid glucosides, dihydrokaempferol, syringic acid, theaflavins, and N -acylated amino acids, respectively.