TY - JOUR
T1 - Free, soluble conjugated and insoluble bonded phenolic acids in Keemun black tea
T2 - From UPLC-QQQ-MS/MS method development to chemical shifts monitoring during processing
AU - Lai, Guoping
AU - Cui, Yuqing
AU - Granato, Daniel
AU - Wen, Mingchun
AU - Han, Zisheng
AU - Zhang, Liang
N1 - Publisher Copyright:
© 2022 Elsevier Ltd
PY - 2022/5
Y1 - 2022/5
N2 - Phenolic acids, including benzoic acid and hydroxycinnamic acid derivatives, are the main compounds of black tea. An efficient and accurate analytical method to quantify ten phenolic acids was established and validated by ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UPLC-QQQ-MS/MS). The chemical shifts during the processing of Keemun black tea were analyzed and the phenolic acids were quantified. Compared with fresh tea leaves, after processing, the contents of free phenolic acids, including gallic acid, salicylic acid, p-coumaric acid, and ferulic acid, increased markedly. Still, the contents of soluble conjugated phenolic acids, including p-coumaroylquinic acid isomers and chlorogenic acid isomers, decreased. Furthermore, the total contents of lignin, and insoluble bonded phenolic acids decreased. The adduct of (-)-epigallocatechin gallate and 3-caffeoylquinic acid was detected in tea samples, and its content increased highly after fermentation. The developed and validated analytical method can be used to monitor the manufacturing process of black tea.
AB - Phenolic acids, including benzoic acid and hydroxycinnamic acid derivatives, are the main compounds of black tea. An efficient and accurate analytical method to quantify ten phenolic acids was established and validated by ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UPLC-QQQ-MS/MS). The chemical shifts during the processing of Keemun black tea were analyzed and the phenolic acids were quantified. Compared with fresh tea leaves, after processing, the contents of free phenolic acids, including gallic acid, salicylic acid, p-coumaric acid, and ferulic acid, increased markedly. Still, the contents of soluble conjugated phenolic acids, including p-coumaroylquinic acid isomers and chlorogenic acid isomers, decreased. Furthermore, the total contents of lignin, and insoluble bonded phenolic acids decreased. The adduct of (-)-epigallocatechin gallate and 3-caffeoylquinic acid was detected in tea samples, and its content increased highly after fermentation. The developed and validated analytical method can be used to monitor the manufacturing process of black tea.
KW - Camellia sinensis
KW - Chlorogenic acid isomers
KW - Method validation
KW - Tea processing
KW - UPLC-QQQ-MS/MS
UR - http://www.scopus.com/inward/record.url?scp=85125483326&partnerID=8YFLogxK
U2 - 10.1016/j.foodres.2022.111041
DO - 10.1016/j.foodres.2022.111041
M3 - Article
C2 - 35400430
AN - SCOPUS:85125483326
SN - 0963-9969
VL - 155
SP - 111041
JO - Food Research International
JF - Food Research International
M1 - 111041
ER -