Effect of brewing conditions on caffeine content in tea infusions simulating home-made cup of tea

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11310%2F18%3A10383784" target="_blank" >RIV/00216208:11310/18:10383784 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1007/s00706-018-2204-0" target="_blank" >https://doi.org/10.1007/s00706-018-2204-0</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1007/s00706-018-2204-0" target="_blank" >10.1007/s00706-018-2204-0</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Effect of brewing conditions on caffeine content in tea infusions simulating home-made cup of tea

Popis výsledku v původním jazyce

To answer the question &quot;How much caffeine do I have in my cup of tea?&quot; we have developed a simple isocratic HPLC method with UV detection for determination of caffeine. The optimized method exhibits high repeatability; the retention time RSD was lower than 0.4% and RSD of the peak area was lower than 3.5%. The method was applied to five types of tea in loose leaf form differing in level of fermentation (black, pu-erh, oolong, green, and white). The brewing conditions were chosen to be as close as possible to domestic preparation of tea. In this study, we have focused on two important culinary factors: infusion time and brewing temperature. The results show that both investigated factors significantly influence the final content of caffeine in a cup of tea. Increase in caffeine content was up to 29% when the tea infusion was overextracted by 1 min. Increase was even higher (up to 66%) when boiling water was used instead of water of recommended temperature. It indicates that careful attitude to preparation of each type of tea is essential for caffeine content. [GRAPHICS] .

Název v anglickém jazyce

Effect of brewing conditions on caffeine content in tea infusions simulating home-made cup of tea

Popis výsledku anglicky

To answer the question &quot;How much caffeine do I have in my cup of tea?&quot; we have developed a simple isocratic HPLC method with UV detection for determination of caffeine. The optimized method exhibits high repeatability; the retention time RSD was lower than 0.4% and RSD of the peak area was lower than 3.5%. The method was applied to five types of tea in loose leaf form differing in level of fermentation (black, pu-erh, oolong, green, and white). The brewing conditions were chosen to be as close as possible to domestic preparation of tea. In this study, we have focused on two important culinary factors: infusion time and brewing temperature. The results show that both investigated factors significantly influence the final content of caffeine in a cup of tea. Increase in caffeine content was up to 29% when the tea infusion was overextracted by 1 min. Increase was even higher (up to 66%) when boiling water was used instead of water of recommended temperature. It indicates that careful attitude to preparation of each type of tea is essential for caffeine content. [GRAPHICS] .

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10406 - Analytical chemistry

Projekt

—

Návaznosti

S - Specificky vyzkum na vysokych skolach<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2018

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Monatshefte für Chemie - Chemical Monthly

ISSN

0026-9247

e-ISSN

—

Svazek periodika

149

Číslo periodika v rámci svazku

9

Stát vydavatele periodika

AT - Rakouská republika

Počet stran výsledku

6

Strana od-do

1561-1566

Kód UT WoS článku

000442501400010

EID výsledku v databázi Scopus

2-s2.0-85051291848