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Comprehensive Investigation of the Effects of Brewing Conditions in Sample Preparation of Green Tea Infusions

Chemical and biological investigation of green tea has been generally performed while using different infusions that are prepared without consideration of the effects of sample preparation conditions. In this study, for the first time, the effects of green tea brewing conditions on the antioxidant a...

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Autores principales: Jin, Yan, Zhao, Jing, Kim, Eun Mi, Kim, Ki Hyun, Kang, Seulgi, Lee, Heesoo, Lee, Jeongmi
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6539062/
https://www.ncbi.nlm.nih.gov/pubmed/31060206
http://dx.doi.org/10.3390/molecules24091735
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author Jin, Yan
Zhao, Jing
Kim, Eun Mi
Kim, Ki Hyun
Kang, Seulgi
Lee, Heesoo
Lee, Jeongmi
author_facet Jin, Yan
Zhao, Jing
Kim, Eun Mi
Kim, Ki Hyun
Kang, Seulgi
Lee, Heesoo
Lee, Jeongmi
author_sort Jin, Yan
collection PubMed
description Chemical and biological investigation of green tea has been generally performed while using different infusions that are prepared without consideration of the effects of sample preparation conditions. In this study, for the first time, the effects of green tea brewing conditions on the antioxidant activity and chemical profiles of metabolome and catechin compounds were examined at 60 °C and 95 °C for a period of 5–300 min. The antioxidant capacities of the tea infusions, which were assessed as per 2,2-diphenyl-1-picryl-hydrazyl hydrate (DPPH) radical scavenging activity, depended more on temperature than time. Metabolomics study that was based on ultra-high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UHPLC-QTOF/MS) revealed that the metabolic profiles, including 33 differential metabolites, were significantly changed by temperature and time, with the effects of time being more evident at 95 °C starting after 30 min. Infusions that were brewed at 95 °C for greater than 30 min yielded distinct profiles in the hierarchical clustering analysis. The quantification of eight catechins by UHPLC-QqQ/MS showed that the total catechin level peaked at 95 °C brewing at 10 min, after which the levels of four epi-forms of catechins decreased and those of four non-epi-forms increased, implying the epimerization of catechins over time. These results suggest that the brewing conditions for sample preparation of green tea should be put into careful consideration in studies where green tea extracts are applied as aqueous infusions.
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spelling pubmed-65390622019-05-31 Comprehensive Investigation of the Effects of Brewing Conditions in Sample Preparation of Green Tea Infusions Jin, Yan Zhao, Jing Kim, Eun Mi Kim, Ki Hyun Kang, Seulgi Lee, Heesoo Lee, Jeongmi Molecules Article Chemical and biological investigation of green tea has been generally performed while using different infusions that are prepared without consideration of the effects of sample preparation conditions. In this study, for the first time, the effects of green tea brewing conditions on the antioxidant activity and chemical profiles of metabolome and catechin compounds were examined at 60 °C and 95 °C for a period of 5–300 min. The antioxidant capacities of the tea infusions, which were assessed as per 2,2-diphenyl-1-picryl-hydrazyl hydrate (DPPH) radical scavenging activity, depended more on temperature than time. Metabolomics study that was based on ultra-high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UHPLC-QTOF/MS) revealed that the metabolic profiles, including 33 differential metabolites, were significantly changed by temperature and time, with the effects of time being more evident at 95 °C starting after 30 min. Infusions that were brewed at 95 °C for greater than 30 min yielded distinct profiles in the hierarchical clustering analysis. The quantification of eight catechins by UHPLC-QqQ/MS showed that the total catechin level peaked at 95 °C brewing at 10 min, after which the levels of four epi-forms of catechins decreased and those of four non-epi-forms increased, implying the epimerization of catechins over time. These results suggest that the brewing conditions for sample preparation of green tea should be put into careful consideration in studies where green tea extracts are applied as aqueous infusions. MDPI 2019-05-04 /pmc/articles/PMC6539062/ /pubmed/31060206 http://dx.doi.org/10.3390/molecules24091735 Text en © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Jin, Yan
Zhao, Jing
Kim, Eun Mi
Kim, Ki Hyun
Kang, Seulgi
Lee, Heesoo
Lee, Jeongmi
Comprehensive Investigation of the Effects of Brewing Conditions in Sample Preparation of Green Tea Infusions
title Comprehensive Investigation of the Effects of Brewing Conditions in Sample Preparation of Green Tea Infusions
title_full Comprehensive Investigation of the Effects of Brewing Conditions in Sample Preparation of Green Tea Infusions
title_fullStr Comprehensive Investigation of the Effects of Brewing Conditions in Sample Preparation of Green Tea Infusions
title_full_unstemmed Comprehensive Investigation of the Effects of Brewing Conditions in Sample Preparation of Green Tea Infusions
title_short Comprehensive Investigation of the Effects of Brewing Conditions in Sample Preparation of Green Tea Infusions
title_sort comprehensive investigation of the effects of brewing conditions in sample preparation of green tea infusions
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6539062/
https://www.ncbi.nlm.nih.gov/pubmed/31060206
http://dx.doi.org/10.3390/molecules24091735
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